Illinois Natural History Survey bulletin XS l^^i'^ ILLINOIS NOV 201991 or,.^ NATURAL HISTORY SURVEY LIBRARY Our Living Heritage: ^ The Biological Resources of Illinois Edited by Lawrence M. Page Michael R. Jeffords Illinois Natural History Survey Volume 34 Article 4 April 1991 Illinois Natural History Survey Bulletin ILLINOIS NATURAL HISTORY SURVEY Our Living Heritage: The Biological Resources of Illinois Edited by Lawrence M. Page Michael R. Jeffords Illinois Natural History Survey Proceedings of a symposium in celebration of Earth Day 1990 Illinois Department of Energy and Natural Resources Illinois Natural History Survey April 23 and 24. 1990 Illinois Natural History Survey. Lorin I. Nevling. Chief A Division of the Illinois Department of Energy and Natural Resources Printed by Authority of the State of Illinois XI2275-2M-4-91 US ISSN 0073-4918 Graphic Design: Gail Glende Rost Computer Graphics: Molly Hardin Scott Editor: Audrey S. Hodgins A catalog of the publications of the Illinois Natural History Survey is available without charge from the address below. A price list and order blank are included with the catalog. Illinois Natural History Survey Distribution Center 607 East Peabody Drive Champaign, Illinois 61820 Manuscripts of high quality dealing w ith any aspect of natural history will be considered for publication in one of the Illinois Natural History Suney series: Biillvtin. Bio/ofiical Norcs. Circiilar. and Special Publication. Authors w ho are not employees of the Survey are required to pay printing costs. Manuscripts should follow the recommendations of the third edition of the Council of Biological Editors Style Manual except that journal names in literature cited are to be spelled in full. The Survey expects to publish only one or two manuscripts by non-Survey authors yearly. Send three copies of manuscripts to be consid- ered for publication to Office of the Chief. Illinois Natural History Survey. 607 East Peabody Drive. Champaign. Illinois 61820. Before a manuscnpt is accepted for publication in the Bulletin or Biological Notes, it must be recom- mended by two or more outside referees. Citation: Page. L.M., and M.R. Jeffords, eds. 1991. Our living heritage: the biological resources of Illinois. Illinois Natural History Sur\'ev Bulletin 34(4): 357-477. Foreword We live in a world of near continuous monitor- ing. In our automobiles we monitor the status of fuel, oil pressure, temperature, and seat belts through gauges, lights, and electronic voices. The consumption of electricity and fuel in our homes is monitored as is the chlorine in our drinking water and the alcohol in our beer. Manufacturers retain quality assurance inspec- tors and issue warrantees and guarantees to convince us that all is well. We monitor our schools and measure our own progress through grades and proficiency scores. It seemed appropriate, therefore, that the Illinois Natural History Survey should take a measure of the living natural resources of Illinois by bringing together a knowledgeable group of persons to summarize the state of the State. In order to share this information and to provide an opportunity for discussion, a symposium, "Our Living Heritage: The Biological Resources of Illinois," was sponsored by the Illinois Depart- ment of Energy and Natural Resources and organized by the Survey. The event, timed to coincide with Earth Day 1990 celebrations, was held on April 2.^ and 24 on the campus of the University of Illinois at Urbana-Champaign. It was attended by nearly 250 professional scientists from some 50 agencies and institu- tions along with a number of interested and dedicated citizens. To share the results of that symposium with an even larger audience, we have issued this publication of its proceedings. To address the salient features of the living resources of Illinois in an ordered fashion, the symposium was presented in five sessions: forests, prairies and barrens, wetlands, streams and caves, and agro-urban ecology. When we consider that only (.).59t of Illinois remains in undisturbed natural areas, that Illinois ranks 46th among states in publicly owned open space per person, that forest acreage has decreased by 73% in the past century and tallgrass prairie by over 99%, that 85% of our wetlands have been lost, that soil erosion proceeds at the rate of 200 million tons per year, and that approximately 30,000 tons of herbicide and 3,500 tons of insecticides are used annually on agricultural crops in Illinois, we can scarcely imagine the tone of the symposium to have been anything but pessi- mistic. In part, there was discouragement, but it was tempered by positive developments, including the designation of the Middle Fork of the Vermilion River as a National Wild and Scenic River, the acquisition of the Cache River Basin, the initiation of a study to identify high-quality Illinois streams based on biodiver- sity, and the ever quickening actions of the Nature Preserves Commission. Preservation/conservation has been in conflict with consumption/development since the days of Theodore Roosevelt. At times one side seems to prevail over the other, but the balance has been clearly on the side of con- sumption. Special interest groups have to a considerable extent managed to give the word enviroiwu'iualist a pejorative cast and the word development a positive ring. During the past decade, the executive branch of the federal government has determinedly downplayed environmental concerns, and that stance has been translated into inertia in a number of federal agencies with responsibility for natural resources. The focus of the United States Environmental Protection Agency, for example, has until very recently ignored the living components of the environment. At the same time, public sensitivity to environmental concerns has dramatically increased, primarily through public service television and other iTiedia-generated presentations on tropical deforestation, extinction of species, depletion of the ozone layer, agro-chemical contamina- tion of groundwater, and the effects of acid rain. Some of this concern is now being transformed into political action. Polls suggest III that the public understanding of environmental matters is quite high, and some beheve that it exceeds the perceptions of elected officials. A Green Party has emerged in this country only very recently, but Greens are a part of both major political parties and the trend in federal legislation may soon begin to sway in favor of conservation/preservation and away from consumption/development. The National Institutes for the Environment may well become a reality within the next several years. Within this tentatively encouraging national picture, the symposium was timely indeed. One symposium event of special interest cannot be documented in these proceedings — the "citizens respond" program of Monday evening, April 23—and I would like to note it here. Michael Jeffords and Susan Post of the Survey opened that session with a mulitmedia presentation on the biodiversity of Illinois. Their slides of representative plants and animals and habitats of the natural divisions of Illinois brought home to us the beauty and fragility that can yet be discovered in the landscape of our state. A panel presentation by five environmental activists followed: Clark Bullard, Office of Energy Research at the University of Illinois at Urbana-Champaign; Max Hutchison, Natural Land Institute of The Nature Conservancy; Lawrence Page of the Illinois Natural History Survey; Donna Prevedell, farmwife and contributing editor to the Progressive Farmer, and Michael Reuter. Volunteer Stewardship Network of The Nature Conservancy. They spoke briefly but openly on preservation activities in which they had been closely involved. The discussion was then turned over to the audience, who asked ques- tions and shared their experiences—successes and failures—with preservation efforts. I urge you to read on in order to under- stand the status of the biological resources of Illinois and to appreciate how much remains to be accomplished to secure their future—and ours. I would be remiss, however, if I did not conclude by acknowledging the committee of Survey staff who planned and conducted the symposium: Lawrence Page, Michael Jeffords, Joyce Hofmann, Susan Post, Louis Iverson, and Audrey Hodgins. Their efforts included developing the program, arranging for speakers and facilities, producing and mailing promo- tional materials, and welcomine the audience. Without their enthusiasm and hard work, the symposium v^ould not have materialized and our understanding of the biological resources of Illinois would be much diminished. Lorin I. Nevling. Chief Illinois Natural History Suney IV Contents FOREWORD iii INTRODUCTION 357 SESSION ONE: FORESTS 359 Forest Resources of Illinois: What Do We Have and What Are They Doing for Us? Louis R. Iverson 361 Forest Succession in the Prairie Peninsula of Illinois John E. Ebinger and William E. McClain 375 Effects of Forest Fragmentation on Illinois Birds Scott K. Robinson 382 SESSION TWO: PRAIRIES AND BARRENS 383 Illinois Prairies: A Historical Perspective Roger C. Anderson 384 Prairie and Savanna-restricted Insects of the Chicago Region Ron Panzer 392 Prairie Birds of Illinois: Population Response to Two Centuries of Habitat Change James R. Herkert 393 SESSION THREE: WETLANDS 400 Aquatic and Wetland Plants of Illinois John E. Schwegman 401 Breeding Biology and Larval Life History of Four Species of Amhystoma (Amphibia: Caudata) in East-central Illinois Michael A. Morris 402 Ecological Integrity of Two Southern Illinois Wetlands M. Ann Phillippi 403 Status and Distribution of Wetland Mammals in Illinois Joyce E. Hofmann 409 SESSION FOUR: STREAMS AND CAVES 4 1 6 The Fishes of Illinois: An Overview of a Dynamic Fauna Brooks M. Burr 417 The Aquatic Mollusca of Illinois Kevin S. Cummings 428 Streams of Illinois Lawrence M. Page 439 Illinois Caves: A Unique Resource James E. Gardner 447 SESSION FIVE: AGRO-LRBAN ECOLOGY 453 The Land Use Controversy: Maintaining and Increasing Biotic Diversity in the Agricultural Landscape of Illinois Michael E. Irwin 454 Farm Programs. Agricultural Technologies, and Upland Wildlife Habitat Richard E. Warner 457 Evaluating Alternatives for Urban Deer Management James H. Witham 458 Illinois Railbanking Study Richard Pietruszka 459 Closing Remarks Brian D. Anderson 460 APPENDICES Appendix One: Native Illinois Species and Related Bibliography Susan L. Post 463 Appendix Two: County Reference Map 476 Introduction The term biodiversity has not yet made its way into most dictionaries, but the word is generally accepted to mean the organisms that inhabit the Earth and the ecosystems in which they hve. Lying at the junction of the eastern forest, western great plain, southern coastal plain, Ozark uplift, and northern forest biomes, Illinois provides habitat for an extremely varied native flora and fauna. Scientists at the Illinois Natural History Survey recently compiled data on the biodiversity of Illinois and conservatively estimated that more than 53,000 species are native to the state (Appendix I). The largest groups are insects with about 17,000 species and fungi with about 20,000 species. In addition, Illinois is home to 2,068 species of vascular plants and 649 species of vertebrates (mammals, birds, reptiles, amphibians, and fishes). The biodiversity of Illinois is more readily appreciated when it is compared to that of other regions. Consider, for example, that the Pine Hills-LaRue Swamp region of southwestern Illinois contains about 1,000 native species of plants. The Great Smoky Mountains National Park, an area of wilderness about 260 times larger, contains only 1,200 native plant species. That same region of southwestern Illinois also has more amphibian and reptile species (61 ) than are found in any region of comparable size in the United States. Perhaps equally surprising, one-fourth of all the freshwater fishes and mussels of North America north of Mexico are found in Illinois. The destruction of tropical rainforests, which are thought to contain over half the total species of organisms, has been widely publi- cized, but all ecosystems are threatened as human populations and their support systems expand. Illinois, one of the most altered regions on Earth, is experiencing an ongoing and accelerating loss in variety as well as absolute numbers of organisms. At least 1 15 species are known to have been extirpated in recent decades (Appendix I), and another 497 are officially listed in Illinois as threatened or endangered. Unless circumstances change dramatically. Illinois will soon have lost 1 in 5 of its native species of fishes, 1 in 5 of its native flowering plants, 1 in 5 of its native birds, 1 in 4 of its native mammals, and a startling one-half of its native freshwater mussels! Historical accounts of Illinois noted huge trees, vast grasslands, and extensive wetlands. Illinois was chiefly a combination of flat, mesic, "marshy" prairies and forested hilly country. Interspersed in these habitats were sand dunes, bogs, fens, .sedge meadows, savannas, and swamps. Unfortunately, little of that original landscape remains. In fact. Illinois ranks an unenviable 49th among states in the percentage of natural areas surviving. Of the original 22 million acres of prairie, only 2.300 acres (0.01%) remain. Of the 14 million acres of forest present in Illinois in 1820, only 13.500 acres of primary (undisturbed) forest survive (0. 10%). Many of our wetlands have been, and continue to be, drained before they can be biologically inventoried and their value determined. Our streams are polluted and increasingly degraded by the influx of soil from surrounding farmland. A significant portion of the biodiversity of Illinois will soon disappear unless the remaining species-rich areas are protected. Several factors contribute to the global loss of biodiversity: the explosive growth of the human population, widespread and extreme poverty and malnutrition, and a notable lack of sustainable, productive agricul- tural and forest systems in many regions of the world. This loss is of paramount importance because human existence depends on the biological resources of the planet. Our prosperity and well-being are based largely on our ability to take advantage of the properties of plants, animals, and microorganisms for 357 358 Illinois Natural Histor)' Survey Bulletin Vol. 34 Art. 4 food, clothing, medicine, and shelter. As species are lost, we reduce our options for future development of vital commodities. As habitats and ecosystems are lost, we lose the recreational potential of wild places, and we disturb the balance of atmospheric gases, including oxygen, carbon dioxide, and ozone. Although the link between biodiversity and human survival is clear, we must also learn to value the biodiversity of our planet and state for its own sake, quite apart from direct benefits to us. The loss of biodiversity is a global problem, but the loss of Illinois biodiversity is of special concern to Illinoisans. In our state, the major cause of the loss of species is the destruction and degradation of habitat. The anthropogenic changes associated with agricul- ture and urbanization cause environmental degradation and lead to the extincfion of species. If the loss of its native biodiversity is not halted. Illinois could become a biological desert unable to respond to the need for new products and incapable of developing resource- based solutions to human problems. At issue is how we will protect the natural habitats that remain, restore some of the natural areas that have been lost, and balance the protection of biodiversity against conflicting social and economic interests. If we are to make informed decisions, we must first complete the following tasks. Inventory the biological resources of Illinois. Our know ledge about the biodiversity of Illinois is incomplete. This lack of infomia- tion hampers our ability to estimate the size and nature of the problem and to recommend remedial measures. We are unable to identify all the biological resources at risk because no inventory of all life forms exists. Although our knowledge of some taxa is extensive, other groups are largely unknown. Species are lost before they are discovered and studied. Even in groups that are well studied (e.g.. birds and fishes), changes are occurring so rapidly that additional data are needed if wise decisions relative to development and management are to be made. Devel(»p the scientific base on which the emerging fields of conservation biology, restoration ecology, and environmental management can be built. Recent global and reszional environmental chanues and the inevitability of future modifications underscore the need for prudent decisions regarding the protection and use of natural resources. Indices are needed that will enable us to compare habitats and select outstanding natural areas for management and protection. Educate Illinoisans regarding the im- portance of biological diversity. Biodiversity is of particular interest to biologists and ecologisis, but all citizens must be informed about the global biodi\ersit\ crisis if protective legislation is to be enacted and funding ensured. Encourage socio-economic research related to the wise use of biodi\ ersity. We need theoretical and empirical studies on the economic and social causes of the biodiversity crisis, its consequences, and its remedies. Sponsored by the Department of Energy and Natural Resources and the Illinois Natural History Surve>. the symposium ""Our Living Heritage: The Biological Resources of Illinois" was held in celebration of Earth Day 1990 on the Urbana-Champaign Campus of the Univer- sity of Illinois. Two days. April 23 and 24, were spent reviewing present information about the biodiversity of Illinois and identifying actions necessary to understand and conserve the remaining resources of our state. Sessions were arranged by ecosystem (forests, prairies and barrens, wetlands, streams, caves, and agro-urban habitat), and contributors discussed what is know n about how these ecosy stems function, how they have been modified, and how various decisions are likely to affect their survival. The proceedings that follow summa- rize infonnation on the biodi\ersit\ of Illinois and suggest where additional research is needed. Nineteen of the twenty-two presenta- tions delivered at the symposium are included here, either as abstracts or papers. Mthough the audience agreed that more information on certain subjects and groups of organisms is needed, they also acknowledged that we knov\ enough to conclude that we have already drasticall\ altered most of our native landscape and that we are rapidl\ losing native species. Without greater protection and more extensive management of natural areas, the loss of habitats and species can only accelerate. Session One: Forests Like ihe first farmsteads, towns of the fiontier were hiiilt in stiinipUiiid meadows. The trees were none. The civic landscapes sweltered in tlie sun. Never so quick an aftertlioiii;lit: fast-f-rowlni; l^lack lixiist trees were imported anil planted everywhere, from C()llef>e cainpnses to coiirtliouse squares, to provide a promise of shade. What irony—the sons of the world's most incredible a.xemen plaiitinii seedlings in the shadow of stumps five feel acro.'is.—Robert O. Petty I In 1820. approximately 13.8 million acres of Illinois were forested. The midcontinental location of the state and its north to south distance of nearly 400 miles allowed an unusual variety of forest types to exist. The pre- settlement forests of Jo Daviess County covered nearly 80% of the land surface and were noted for their rugged topography and the presence of Pleistocene relic species. In 1830, a U.S. Government geologist surveying the Grand Prairie Division in central Illinois observed. "Sometimes the woodland extends along this river for miles continuously, again it stretches in a wide belt off into the country, marking the course of some tributary streams, and sometimes in vast groves of several miles in extent, standing alone, like islands in the wilderness of grass and flowers. "' Robert Ridgway. a Smithsonian naturalist, noted the immense size and diversity of the trees along the lower Wabash Valley in the 1870s. With photographs and measurements, he documented the extraordinary nature of the bottomlands. In the Shawnee Hills the relatively broad, flat- bottomed ravines, originally cut by the melt- waters of the Illinoian glacier, were verdant, damp jungles filled with trees—beech, sugar maple, and tulip— that reached and overtopped the sandstone bluffs. South of the Shawnee Hills the terrain flattened and a distinctly .southern forest grew in the past and present Ohio River valleys. Great expanses of bald cypress-water tupelo swamps filled the lowlands along the Cache and Ohio rivers. Rare species like willow oak. silverbcll. water hickory, and American chestnut occupied river terraces, flatwoods, and ravines. We know of these magnificent forests for several reasons. Early settlers to Illinois, while greatly impressed with the vast expanse of prairie, chose to live in the woodlands, a landscape with which Europeans felt more familiar. Thus the nature of these forests came to be better documented than that of other landscape types. In addition, early biologists like Ridgway and the St. Louis physician George Engelmann described the presettlement condition of Illinois forests in considerable detail. To begin to understand the current condition of Illinois forests we must reflect upon their past and on what has been lost. Robert Ridgway. writing in the American Naturalist in the 1 870s. described the forests along the Wabash River. "If the forest is viewed from a high bluff, it presents the ap- pearance of a compact, level sea of green, apparently endless ... the tree-tops swaying with the passing breeze, and the general level broken by occasional giant trees which rear their massive heads so as to overlook the surrounding miles of forest . . . while the occasional, and by no means infrequent, 'monarchs" which often tower apparently for one-third their height above the tree-top line, attain an altitude of more than one hundred and eighty feet, or approach two hundred feet." In the visitor center of Beall Woods, an Illinois Nature Preserve in Wabash County, an im- mense yellow outline painted on the floor represents one of these last great trees. The circle is seventeen feet in diameter. Today nearly 4.3 million acres of trees can be found in Illinois, not too startling a decline in acreage from 1 820 if we consider the agricultural and urban development that now blankets the state. Lest we are loo complacent, however, wc should recall that much of the forest acreage of today is second- or third- growth timber or pine plantations; only 13.500 acres of relatively undisturbed forests remain— a shockingly small percentage of our rich, forested heritage. I-ortunately. fragments remain of nearly all forest types found in 359 360 Illinois Natural History Survey Bulletin Vol. 34 Art. 4 presettlement times and these, in conjunction with land survey records, early written ac- counts, and good biological detective work, allow us to mentally reconstruct, and some- times physically restore, the various forest habitats. These efforts, to some extent, provide a glimpse of what was once Illinois. The three papers given at this session help us to conceptualize the forests that were once so integral to the Illinois landscape and to understand how the forests that exist today came to be. In addition, they enable us to appreciate the role that forests play in the economy of the state, in preserving biodiversity and habitat for wildlife, in controlling erosion and improving the quality of surface water, and in conserving energy and slowing global warming. Forest Resources of Illinois: What Do We Have and What Are They Doing for Us? Louis R. Iverson, Illinois Natural History Survey Forests occupy only a relatively small propor- tion (12%) of the land area of Illinois (Figure 1), yet they provide tremendous benefits to the citizens of the state. We need only walk through the woods to be aware of some of these benefits: aesthetic beauty, habitat for special- ized plants and for birds and other wildlife, recreational opportunities, and high-quality hardwood. The more subtle but equally impor- tant benetlts that forest ecosystems provide, however, are not so readily perceived. Forested acres, for example, dramatically inhibit soil erosion, thereby reducing the sediment load that eventually finds its way into our water courses; no forest benefit is more important when we consider that 3.3 pounds of soil are lost for each pound of grain produced in Illinois (Iverson et al. 1989). Global wanning, due largely to the excessive buildup of carbon dioxide in the atmosphere, is also counteracted to some degree by our forests because plants convert tremendous quantities of carbon dioxide into plant tissue and oxygen each day. Then too, our forests contribute greatly to the maintenance of biological diversity, a benefit of crucial importance in Illinois where the land- scape is dominated by a row-crop monoculture. The purpose of this paper is to review the historic trends that shaped the Illinois forest, to document its present status, and to summarize Cropland 24.7 Forestland 4..'^ Urban 2.6 Pasture 2.4 Other 1.2 Nonforest with trees 0.9 Figure 1 . Major land use in Illinois in niiliions of acres, 1985. Total acres in Illinois = 36.06 1 ,()(X). Source: Hahn 1987. the benefits it currently provides. The material is largely condensed from a more detailed and complete document. Forest Resources of Illinois: An Atlas and Analysis ofSpatial and Temporal Trends (Iverson et al. 1989). Readers are encouraged to consult that book and the map (Iverson and Joselyn 1990) that accompa- nies it for a great deal more information regarding the forests of Illinois, including data specific to the counties in which they may be particularly interested. Both the book and map are available as Special Publication 1 1 from the Illinois Natural History Survey. Much of the story of the Illinois forests can be understood by comparing the earliest systematic vegetation data available for the state, data recovered from the original land surveys made during the first half of the nineteenth century, with recent land-use infor- mation taken via remote sensing from airplanes and satellites. FORESTS OF 1820 Illinois was surveyed by the United States General Land Office between 1 807 and 1 844. Starting from southern Illinois and working northward, surveyors divided the land into townships and sections, prepared plat maps, and made notes on the vegetation they encoun- tered. These records provide a fairly complete picture of the landscape prior to the massive disturbance caused by European settlement. Anderson ( 1970) published a map showing the statewide distribution of forest and prairie as deduced from these data (Figure 2). Large expanses of forest existed, primarily in the south and west. Approximately 38.27f of the state (13.8 million acres) was forested at the time of the European settlement, 61.2% was prairie, and 0.6% was water. Fifteen counties were at least 80% forested, and only 21 counties had less than 20% forest cover. 361 362 Illinois Natural History Surxey Bulletin Vol. 34 An. 4 FOREST TRENDS 1820-1980 Illinois forests have undergone drastic changes in the decades since European settlement. Only 3 1 % of the forest area present in 1 820 exists today (Figure 3). The lowest percentage of forest occurred about 192(1 when only 22'/( of the land forested in 1820 remained in forest (Telford 1926; U.S. Fore.st Service 1949; Essex and Gansner 1965; Hahn 1987). Although forest area has increased in recent decades, most of today's forest is secondary forest, and only about 1 1.600 acres exist in a relatively undisturbed condition (Illinois Natural Areas Inventory as reported in Iverson et al. 1989). Illinois ranks 49th, next to Iowa, in percent of the state converted from its "potential"" vegeta- tion type (Kiichler 1964); only 1 1 percent of the state remains in its "potential" vegetation type and essentially all of that is forest (Klopateketal. 1979). The pattern of deforestation of the primary (i.e.. "virgin"") forests of Illinois can be deduced to some degree by relying on estimates of forestland in 1820 and 1924 and on other written accounts (especially Telford 1926). From initial settlement in the early 1800s to 1860, agriculture was the only important industry associated with wooded lands. Until 1 830. forests were the sole source of potential agricultural land; hov^ever. when settlers realized that the prairies made good cropland and after the invention of the moldboard plow, the prairies were converted to cropland at an astonishing rate of approximately 3.3'7r per year (Table 1 ). Over 300.000 people settled the prairies during the decade of the 1 830s. and this burgeoning population created an enormous demand for housing material, fuel, and fence posts. Railways were not yet in place to import lumber, and most of the timber in the prairie counties rapidly disappeared. ^m^m Figure 2. Forests in Atidcrsoti 1970. Figure .<. Forests in Illinois about 1980. Source: U.S. Geological Surve\ land-use data. 1973-1981. April 1991 SympoMum Proceedings: Our Living Heritage 363 By 1860. a timber industn had begun to flourish in lihnois. Ninety-two of the 102 counties had industries based on wood products by 1870, and forestland had dwindled to 6.02 million acres (Telford 1926). During the 1880s. annual lumber production exceeded 350 million board feet, 2.2 times the present production, and continued to increase until 1900, when it began to decrease as the resource itself de- clined. By 1923, only 22,000 acres of the original 13.8 million acres of primary forest remained. A useful comparison can be made between deforestation in Illinois in the nine- teenth century and the deforestation presently under way in the tropics. The primary forests of Illinois went from 13.8 million acres in about 1820 to 6 million acres in about 1870, to 22,000 acres in about 1920 (Figure 4). an overall deforestation rate of 1% per year (1.13% of the original primary forest lost during the first half of the century, 0.87% during the .second half). Deforestation rates, however, were not a constant during the period and probably followed a curve such as that shown in Figure 5, with ma.ximum deforesta- tion in the late 1800s. Rates of deforestation have also been compiled for Rondonia in Brazil (Malingreau and Tucker 1988). for Costa Rica (Sader and Joyce 1988). and for Malaysia (Iverson et al. 1990) and are shown in Table 1. The fastest rate. 2.47% annually, was found from 1972 to 1982 in peninsular Malaysia, even though more forestland was being removed in Rondonia. This rate was probably equaled in Illinois in the late 1800s (Figure 5). A similar curve is currently found in the other countries, with Malaysia at the apex of the curve. Rondonia on the upward slope w ith increasing rates, and Costa Rica on the down- ward slope with a declining resource and a dropping rate. History does indeed repeat itself, and we Americans should acknow ledge our own history of deforestation as we now attempt to curb the destruction of tropical forests. FOREST TREND.S 1962-1985 Forest area increased by 10% from 1962 through 1985, from 3.87 to 4.26 million acres. This increase is partially explained by the reduced number of cattle raised in Illinois and the conversion of pastures and hay land to secondary forest. Total net volume of growing stock has also increased 40% since 1962 (Table 2). Pine plantations have shown the highest percentage of increase in volume (up to 375% ), but the largest absolute increase in \ olume was shown by oaks (an increase of 0.64 million cubic feet). Acres 10,000.000 1 ,000,000 100,000 lO.OOd 1820 1870 1924 1948 1962 1985 Figure 4. Extent of Illinois primary forests, 1820- 1983. Interpreted from Telford 1926; U.S. Forest Service 1949: and Anderson 1970. Table 1. Recent rates of land clearing in three tropical countries compared with rates of land clearing in Illinois from 1820 to 1923. Location Land use \CM Sq km of land Percent cleared per year Rondonia. Brazil 364 llinois Natural History Survey Bulletin Vol. 34 Art. 4 Compositional changes during 1962-1985 were especially profound, with vast percentage increases in commercial acreage of white, red, and jack pines, oak-gum-cypress, and especially maple-beech forest types (Figure 6). Maples increased 41-fold in the past 25 years—from 0.025 million acres to 1 .046 million acres! Concomitantly, oak-hickory decreased by 337,000 acres (14%), and over half of the state's elm-ash-soft maple dis- appeared. The loss of oak-hickory is largely from maple "take-over" as shade-tolerant maples replace oak-hickory stands following mortality or harvest. A documented case of the maple take-over of a forest in east-central Illinois is presented later in these proceedings (Ebinger and McClain. page 375) and else- where (Ebinger 1986). The reduction of elm-ash-soft maple is due to mortality from Dutch elm disease and the conversion to cropland of bottomland forests that once supported this forest type. These data make clear that although forest acreage and volume have increased since 1962, the quality and value of the timber resource has diminished, at least by today's standards. Maple-dominated forests also support a somewhat different array of wildlife than that supported by oak-domi- nated forests, and such "hard mast" (acorns and hickory nuts) feeders as squirrels and wood- peckers are less abundant in maple-dominated forests. ILLINOIS FORESTS TODAY A closer look at the current status of the Illinois forests reveals some interesting and on occa- sion surprising information. Area Estimates of current forestland compiled from the 1985 U.S. Forest Service inventory indicate that about 12% (4.27 million acres) of the land area of Illinois is forested (Hahn 1987). The extent of this forestland can be seen in Figure 3 (as well as in several forms on the 1:500,000 scale map of Iverson and Joselyn 1990). The importance of the southern and western counties is clear. At one extreme is Ford County with only 3,000 acres of forestland; at the other is Pope County with 149,200 acres, Jackson with 134,500, and Pike with 122,500. Included in this 4.27 million acres are 4,029,900 acres of commercial (capable of and potentially available to produce commercially valuable trees) forestland and 235,600 acres of reserved or protected timberland. Wooded strips less than 1 20 feet wide and land on which at least one tree (5 inches in diameter at breast height) occurs per acre make up a category that has been designated "non- forestland with trees. " Included in this category- are wooded strips ( 178.5(X) acres), wooded pastures ( 162,400), urban and other built-up land ( 1 39,500). windbreaks (1 33. 1 00), im- proved pastureland with trees (103.600). urban forest (102,800), and several miscellaneous classes. Taken together. 9(X),800 acres of nonforestland with trees are found in Illinois. Composition The composition of many Illinois forests has changed over the past several decades. Today, about one-half of the commercial forest acreage Percent cleared per year 2.5 1920 Figure 5. Rate of forest clearing in Illinois. 1840- 1920. Interpreted from Telford 1926: U.S. Forest Service 1949: and Anderson 1970. Acres (X 1000) 2,500 2,000 1962 D 1985 April 1991 Symposium Proceedings: Our Living Heritage 365 Table 2. Net volume of growing stock on commercial forestland in Illinois by species group for 1962 and 1985, percent change between those dates, and net annual growth estimated from 1985 data. 366 Illinois Natural History Survey Bulletin Vol. 34 An. 4 high diversity of woody plant species consider- ing the extensive agricultural acreage. Trees account for 261 taxa, shrubs 284, and lianas 47 (some taxa include more than one type). These woody plants account for a diversity of cover types and occupy a variety of habitats. On average, 70 tree taxa and 54 shrub taxa have been recorded from each county (Iverson et al. 1989). Southern counties have the largest number of tree taxa (Jackson has 145 taxa. Pope 129, and Union 128), and northeastern counties have the most shrub taxa (Cook has 153 and Lake 136). Volume, Annual Growth, and Number Net volume estimates for 1985 showed the prominence of oak and hickory in commercial forests, with considerable amounts of ash. black walnut, cottonwood, elm, maple, and sycamore as well (Figure 7). The data shown in Figure 7 may have greater immediacy if we consider that 1 million board feet provide enough lumber to build an estimated 73 wood houses. The total net volume of Illinois timber in 1985— 17.5 billion board feet—would theoretically build 1.3 million wood houses! Total net volume estimates of growing stock were 4.8 billion cubic feet, an average of 47.4 million cubic feet per county or 1 ,200 cubic feet per acre of commercial forestland in the state. Hard hardwoods (predominately oak, hickory, and ash) accounted for 68% of total volume; soft hardwoods (e.g., elm and soft maple) accounted for 30% and softwoods (e.g., pine) made up 2%. According to annual growth estimates for 1985 (Hahn 1987). growing .stock showed 96 million cubic feet of growth, or 437 million board feet of sawtimber growth. Over 42% of net annual sawtimber growth was accounted for by oaks, with another 10% from soft maple. 6.3% from ashes. 3.7% from black cherry. 3.3% from hard maple, and 3.2% from black walnut. Only elm and black ash showed negative growth rates between 1962 and 1985, and these are attributed to Dutch elm disease and the clearing of bottomlands. The estimated number of trees in Illinois commercial forests revealed a somewhat surprising statistic: the elms, with 344 million trees, were the most common group. Most of these, however, are small slippery (or red) elms with little commercial value (Figure 8). Overall, white oaks (99 million), red oaks ( 136 million), hickories ( 185 million), hard maples (117 million), and soft maples (91 million) were very abundant. Age Illinois forests are reasonably well distributed among age classes, with 61 -year to 80-\ear classes most prevalent: however, certain trends appear when the ages of major forest types are considered (Figure 9). Oak-hickory forests show a very uneven age distribution, w ith the majority older than 60 years. A predominance of maple-beech is found in younger age classes (<30 years) relative to oak-hickory and elm-ash-soft maple. This pattern again illustrates, as it did in the data on acreage trends (Figure 6). two important aspects of Illinois forests today: maples are rapidly increasing in younger age classes and forest types dominated by oaks and elms are declining and have relative!) fewer trees in younger age classes. Among the other forest t> pes. w hite Oak 8,833 Other Hardwoods l.Sl.'i Maple 1.766 Hickory \.559 Ash 783 'Cottonwood 710 Sycamore 603 Elm 483 Walnut 368 Softwoods 338 Figure 7. Total volume of Illinois commercial forestland in \'-K5 in million board feci. Total net volume of sawtimber was 17..S billion board tccl. Source: Hahn 1^)87. Elm 344 Other HardwoodsJ j-^^^*^ vv;,ir.,.t Oak 236 Noncommercial 217 Maple 208 Hickor\ 185 114 Walnut 66 508 Softwoods 49 Figure 8. Number ot live trees in 1985 in Illinois commercial forestland in millions of trees. Total number ot trees was 1.93 billion. Source: Hahn 1987. April IWl Symposium Proceedings: Our Living Heritage 367 and shortleaf-loblolly pine peak in the 21- to 30-year class with very little stand acreage under 10 years of age. Pine plantations are no longer being planted to the extent they were from 1930 to 1960. primarily because of changes in the management of the Shawnee National Forest (U.S. Forest Service 1986). Site Forest stands can also be classified according to an index that measures the quality of a site based on the height its trees attain after 50 years of growth. The soils of Illinois are superior for forest growth compared to the relatively shallow or infertile soils of neighbor- ing states like Missouri or Kentucky. According to this index, fully 84*^ of the trees in the commercial forestlands of Illinois are capable of supporting growth of 61 to more than 100 feet during a 50-year interval. Mortality In 1985. the forests of Illinois experienced an annual mortality of over 200 million board feet of sawtimber (67 million cubic feet of growing stock) (Hahn 1987). In contrast. 161 million board feet of timber were cut in 1983 (Blyth et al. 1987); at that time, therefore, more timber Acres (x 1000) 600 500 was dying than was being cut. These mortality data represent an annual death rate of 1 .369^ of the total inventory and 69% of the annual growth of growing stock. These rates are quite high in comparison to the mortality rate (0.97c) in Illinois in 1962 and to rates in neighboring states—central Wisconsin, for example, had an average mortality rate of only 0.8% of its total inventory in 1983 (Raile and Leatherberry 1988). The Illinois secondary forests are aging, with concomitant increasing mortality. Disease accounted for 38% of the mortality, but weather, suppression, and unknown causes were also important (Hahn 1987). Elms suffered the greatest mortality and accounted for 26% of total mortality; 56%- of the elm mortality was due to disease. Ownership Over 90% (3.64 million acres) of the commer- cial forests in Illinois are privately owned, mostly by farmers (45.3% ) and other individu- als (38.1%) (Figure 10). The remaining 10% is publicly owned, primarily by the federal government (7.2%) in the form of the Shawnee National Forest. The Cooperative Extension Service of the U.S. Department of Agriculture estimated that Illinois had 169,073 private 400 300 5 15 25 35 45 55 65 75 K5 95 110 \M) 1.50 Figure 9. Acreage by age classes (in years) of the three major forest types in Illinois in I ')S5. .Source Hahn 1987. 368 Illinois Natural History Survey Bulletin Vol. 34 An. 4 forestland owners, each of whom owned an average of 2 1 .5 acres of forest. The primary reasons for forest ownership given by the holders of small parcels were wildlife habitat and aesthetic value (Young et a). 1984): income was of greater importance for those who owned large forest parcels (McCurdy and Mercker 1986). BENEFITS OF ILLINOIS FORESTS Although Illinoisans would undoubtedly respond in different ways if queried on the benefits of the forests of our state, probably none of them would be in error. The forests of Illinois truly offer multiple benefits and perhaps one of the most encouraging aspects of management is that plans can be designed to accommodate and enhance these varied benefits. Natural Communities In the late 1970s, a search for natural communi- ties relatively undisturbed by human activity was undertaken throughout the state (White 1978). Of the 1,089 natural areas selected for inclusion in the Natural Areas Inventory, 392 (36%) contained forestland; however, only 149 natural areas, a mere 1 1 ,593 acres of forestland. were classified as Grade A (relatively undis- turbed) or Grade B (some disturbance). Of that total, about a third was classified as Grade A. Since that inventory, a few additional high- quality sites have been added, for a total of 157 areas from 62 counties. Lake and St. Clair counties contain the largest number of forested natural areas ( 12 and 1 1, respectively); Peoria has 7. Washington and Mason 6 each, and Massac 5. Adams County has the most exten- sive acreage of high-quality forestland, 1 ,950 acres, followed bv St. Clair (963 acres). Lake Government 9.6% (federal 7.2%, state 1.4%, local 1.0%) Corporate ownership 6.8% hulividiuil: 8.^.4% (farmers 4.'i.3%, nonfamiers 38.1%) Figure 10. Ownershipof Illinois commercial forests. 198.S. Source: Hahn 1987. (635 acres), Johnson (622 acres), McLean (450 acres). Saline (447 acres). Cook (444 acres), and Pike (43 1 acres). Many high-quality forests in Illinois are undergoing degradation because of the invasion of exotic plants. Over much of the state, forests are threatened by garlic mustard (Alliaria peiiolata). Amur honeysuckle (Lonicera maackii). tatarian honeysuckle {L. tatarica). Japanese honeysuckle iL.japoniciis). multiflora rose {Rosa multiflora). autumn olive (Elaeag- nus umhellata). and other introduced species. These exotics reduce the diversity of forest communities by eliminating native understory species. Management strategies must be adopted within the few remaining high-quality forests if they are to be protected from aggres- sive species. Control measures include recruit- ing volunteers for hand weeding, the cautious application of pesticides, and the implementa- tion of biological controls. Perhaps most important is an educational program to teach the public hov\ to identify and control these dangerous invaders. Botanical Diversity Illinois forests provide habitat for an excep- tional diversity of plant species and are the natural home for most trees and other woody species. The 508 taxa of trees, shrubs, and lianas found in Illinois represent 15.9% of the state's reported flora, and 346 (69% ) of them are associated with forest habitats (ILPIN data; Iverson and Ketzner 1988) (Figure 11), Most of the remaining taxa are cultural (escaped from cultivation). Of the 508 taxa. 370 (73% ) are nati\ e to Illinois; the remaining are introduced. A relatively high proportion of the state's woody taxa are listed as rare in Illinois (40%); 15% occur commonh . 33% occur occasionally (common in localised patches), and 12% are Forest, nonwoody taxa 1.235(38%) Nonforcst. nonwoody laxa 1,461(46%) Forest, uoody taxa .^46(11%) Nonforest. w oody taxa 162(5%) Figure 1 1 . Number ol plant laxa by habitat and habit (\\ood\ and noiiuoodv l. Total taxa in Illinois = 3.204. Source: hcrson and Ketzner 1988. April 1991 Syniposiuni Proceedings: Our Living Herilage 369 uncommon (localized distribution or sparse throughout). Illinois forests also provide habitat for an amazing number of nonwoody taxa. Including the woody taxa, fully 1,414 native taxa (61'/f of the native Illinois flora) are associated with forest habitats (Figure 1 1 ). Thus Illinois forests, which occupy only 1 29r of the area of the state, provide habitat for over half of its native flora. If we are to protect this irreplaceable biological diversity, we must maintain and restore forest communities. Beyond the importance of forestland as habitat for total plant diversity, rare plant species are frequently found in forest habitat, for example, 166 taxa (47%) of the 356 plants listed as threatened or endangered in Illinois are forest inhabitants. The importance of high-quality forests as refuges for these taxa cannot be overemphasized, especially in the face of extreme pressures from urban and agricultural growth. Wildlife Habitat Illinois forests provide the major habitat for numerous wildlife species, and losses in the quality and quantity of that habitat severely affect wildlife populations (Illinois Wildlife Habitat Commission 1985). Game species — gray squirrel, eastern wild turkey, quail, and white-tailed deer—depend on woodlands as do many more nongame animals—thrushes, warblers, woodpeckers, nuthatches, kinglets, and whippoorwills— to mention only a few bird species. But some relationships between wildlife and forests are more subtle. Most of us recognize the dependence of wood ducks on natural cavities in the trees of bottomland forests, but bottomland forests also provide food and habitat for fish, mitigate the effects of floods, restrain the movement of harmful chemicals into lakes and streams, and provide shade, thereby lowering water temperatures during stressful summer months. One method of summarizing the value of Illinois wildlife habitat is based on land use. Complete details are presented in Graber and Graber ( 1976), and revised calculations based on current data are given in iverson et al. ( 1989). The habitat evaluation index devised by Graber and Graber is based on the relative amount of a particular habitat type within a given area, the availability of that habitat type within the state or region, the changing availability of that habitat (Is it increasing or decreasing over time?), and the "cost"" of a given habitat measured in years required to replace the ecosystem. A summary ot habitat factors for Illinois as a whole is presented in Table 3. By this calculation, over three-quarters of the wildlife habitat (88 of 1 15.7 habitat factor points) is derived from forests. Elm- ash-cottonwood rates highest because this forest type has been disappearing so quickly over the past two decades (Figure 6). Oak- hickory values would be higher except that numbers in older age classes are increasing as secondary forests mature, even though numbers in younger age classes are decreasing (Figure 9). A very minor rating was earned by maple-beech because this forest type has increased so dramatically in recent years (Figure 6). This method can be used to evaluate wildlife habitat on parcels of various size (see examples in Iverson et al. 1989). In the final calculation, the habitat factor for a given site or region is divided by a regional or statewide habitat factor (1 15.7 for the state). An index of 1 .0. therefore, means that the value of the habitat under consideration is about average for the state or region as a whole. Thus, a habitat evaluation index of 1.5. the value calculated for the 16 southern counties, indicates a much higher wildlife value than the value of the state overall. Similarly, the value of 0.66 for the 60 northern counties indicates a relatively poor Table 3. Habitat factors for Illinois. 19S5. calculated according lo Graber and Graber ( 1976). 370 llinois Natural History Survey Bulletin Vol. 34 An. 4 habitat for wildlife, and the value of 1.09 for the 26 south-central counties indicates wildlife habitat somewhat above that of the state as a whole. Fragmentation of forest habitat has negative implications for wildlife, especially for neotropical migrant birds that need large blocks of uninterrupted forest for successful nesting (Harris 1984; Blake and Karr 1987; Robinson 1988). As large tracts of forest are broken into small, isolated woodlots, more forest edge is created and more opportunities exist for edge-adapted species, most impor- tantly the cowbird. to invade the area and parasitize the nests of many forest songbirds. The extent of fragmentation in Illinois forests was made clear in a recent examination of forest parcels by size. Relying on the Illinois Geographic Information System and data from the U.S. Geological Survey, researchers determined that 10.121 forested parcels exist in the state and that the average size per parcel is 358 acres (Iverson et al. 1989). About 44% of the parcels are less than 100 acres in size and about 10% are larger than 600 acres (Figure 12). Perhaps the density of forest parcels can be pictured more clearly if we envision an area the size of a township—36 square miles. On average, 6.1 parcels exist per township-sized area, with 69% of them roughly 40 (limit of resolution of the data) to 200 acres in size. This perspective makes clear that Illinois forests are extremely fragmented and that a concentrated effort must be made to protect larger forest patches and to aggregate smaller ones. llH)-2()() acres: 2.476(1.3) 201-600 acres: ^^^^^ 2.099 i\ 3) < 100 acres 4.479(2.7) '^^^^kV' , (,01-1.100 acres: \ .325(0.3) >l.l()Oacres:542(().3) Figure 12. Number of forested parcels in Illinois h\ size and average number of parcels per low nship equivalent (36 square miles). Total number ot parcels in Illinois of a given size is the number immediately following the size (e.g.. 76 Miscellaneous 199 Fumiture 161 ontainers Saumills 89 Buildiiifis 31 101 Figure 1.*^. Forcst-relaicd industries in Illinois. 1984. These I ,.'^33 sites etnpkn ed .'>34,342 workers. Source; Dun & Bradstreet data base 1984. April 1491 Symposium Proceedings: Our Living Heritage 373 CONCLUSIONS A great deal of infomiation has been presented to establish the initial contention ot this paper: the Illinois forests provide numerous important benefits to the citizens of the state. Neverthe- less, considerable improvement in the quantity and quality of these benefits could be achieved if forestlands were better managed. Over most of the state, little forest management is under- way, and the potential of our forests to provide vs ildlife habitat, preserve biodiversity, and extend wood production has not been tapped. Even in "wilderness"" areas, management is often necessary to maintain the status quo (e.g., remove exotic invaders). Ecosystems are not static entities: change is inevitable, but only with management can change benefit the resource as well at its human guardians. We need to manage the forest resources we currently possess, but we also need to plant more forests if we are to assure continuing benefits from our forests. Recent political developments have and may continue to support tree planting programs: however, caution is in order. Planting trees requires more than seedlings and a spade. Species most appropriate to a given site must be selected, follow-up care must be available, and long- term management must be provided if the success of these programs is to be ensured. The environmental problems facing Illinois, the nation, and the planet are grave indeed. Yet we are learning the important role that forests can play in mitigating some of these problems. We have, however, only begun to realize the enormity of the task. We have only begun to take the actions needed to create a sustainable world. LITERATURE CITED American Forestry Association. 19XS. Plant a tree—cool the globe. Urban Forest Forum 8:1. II. Anderson. R.C. 1970. Prairies in the prairie state. Transactions of the Illinois Stale Academy of Science 63(2):2 14-221. Blake. J.G.. and J.R. Karr. 1987. Breeding birds of isolated woodlols: area and habitat relationships. Ecology 68:1724-1734. Bi.YTH. J.E.. D.R. MrCuRDY. J.H. Birde. and W.B. Smith. 198.'i. Fuel wood production and sources from roundwood in Illinois. 1983. U.S. Department of Agriculture. Forest Service, Resource Bulletin NC-92. St. Paul, MN. 73 p. Blyth, J.E.. J. A. Sester. and G.K. Raile. 1987. Illinois limber industry—an assessment of timber product output and use. U.S. Forest Service, Resource Bulletin NC- 1 00. St. Paul. MN. 44 p. Cook. E.A.. and L.R. Iver.son. 1991. Inventory and change detection of urban land cover in Illinois using Landsal thematic mapper data. Proceedings of the Annual Meeting of the American Society of Photogrammeiry and Remote Sensing. Bethesda. MD. (in press) Ebinger. J.E. 1986. Sugar maple, a management problem in Illinois forests? Transactions of the Illinois Slate Academy of Science 79( 1 & 2):25-.30. Essex, B.L., and D.A. Gansner. 1965. Illinois" limber resources. U.S. Department of Agriculture, Forest Service. Resource Bulletin LS-3. St. Paul, MN. 56 p. Graber, J.W., and R.R. Graber. 1976. Environ- mental evaluations using birds and their habitats. Illinois Natural History Survey Biological Notes 97. 39 p. Hahn. J.T. 1987. Illinois forest statistics, 1985. U.S. Department of Agriculture. Forest Service. Resource Bulletin NC-103. St. Paul, MN. 101 p. Harris, L.D. 1984. The fragmented forest. Univer- sity of Chicago Press, Chicago. IL. 21 1 p. Iij.iN(3is Council on Forestry Development. 1988. Urban forestry practices in Illinois: analysis of a survey. Urban Needs Task Group Report to the Illinois Council on Forestry Development. Spring- field. 32 p. Illinois Department of Conservation. 1989. Illinois outdoor recreation plan 1988-1993. Illinois Department of Conservation, Springfield. Illinois Wildliee Habitat Commission. 1985. The crisis of wildlife habitat in Illinois today. Illinois Wildlile Habitat Commission Report 1984-1985. Springfield. 26 p. IvERSON, L.R., S. Brown, S. Baum, and A. Lugo. 1990. Forest fragmentation and biomass degradation in West Malaysia during 1972-1982. Bulletin of the Ecological Society of America 71:198. 374 linois Natural Histor> Survey Bulletin Vol. 34 An. 4 IvERSON. L.R., AND M. JosELYN. 1990. Fofest resources of Illinois. 1820-1980, with accompanying maps on forest volume, diversity, and composition. Map. Illinois Natural History Survey, Champaign. IvERSON, L.R., AND D.M. Ketzner. 1988. The Illinois Plant Information Network user's guide. Illinois Natural History Survey Internal Document. Champaign. 92 p. Iverson, L.R., R.L. Oliver, D.P. Tucker, P.G. RissER, CD. Burnett, and R.G. Rayburn. 1989. Forest resources of Illinois: an atlas and analysis of spatial and temporal trends. Illinois Natural History Survey Special Publication 11. 181 p. Klopatek, J.M., R.J. Olson, C.J. Emerson, and J.L. Jones. 1979. Land-use conflicts with natural vegetation in the United States. Environmental Conservation 6:191-199. KucHLER, A.W. 1964. Potential natural vegetation of the conterminous United States. American Geo- graphical Society Special Publication 36. American Geographical Society, New York. 1 16 p. + map. Malingreau, J. p., and C.T Tucker. 1988. Large- scale deforestation in the southeastern Amazon basin of Brazil. Ambio 17:49-35. McCuRDY, D.R., AND D.C. Mercker. 1986. A study of owners of large, private, forested tracts in southern Illinois, 1977-1985. Department of Forestry, Southern Illinois University at Carbondale. 18 p. Northeastern Illinois Planning Commission. 1987. Revised population and household forecasts to 2005. Northeastern Illinois Planning Commission Data Bulletin 87-2. Chicago. 12 p. Raile. G.K., AND E.C. Leatherberry. 1988. Illinois' forest resources. U.S. Department of Agri- culture, Forest Service, Resource Bulletin NC-105. St. Paul, MN. 113 p. Robinson, S.K. 1988. Reappraisal of the costs and benefits of habitat heterogeneity for nongame wildlife. Transactions of the North American Wildlife and Natural Resources Conference 53:145-155. U.S. Department of Commerce. 1982-1985. 1982 census of manufacturers. U.S. Department of Commerce Geographic Area Series. Washington, DC. U.S. Forest Service. 1949. Forest resources of Illinois. U.S. Department of Agriculture, Forest Service, Central States Forest Experiment Station Forest Survey Release 7. Columbus, OH. 53 p. U.S. Forest Service. 1986. Land and resource management plan, Shawnee .National Forest. U.S. Department of Agriculture, Forest Service, Eastern Region, Washington. DC. White. J. 1978. Illinois natural areas inventory technical report. Vol. I. Survey methods and results. Illinois Department of Conservation. Department of Landscape Architecture at the University of Illinois at Urbana-Chainpaign, and Natural Land Institute, Springfield, IL. 426 p. Young, R., M. Reichenbach, and F. Perklhn. 1984. A survey of private non-industrial forest owners in Illinois: a preliminary report. University of Illinois Forestry Research Report 84-2. 5 p. Sader, S.A., and A.T. Joyce. rates and trends in Costa Rica. Biotropica 20:1 1-19. 1988. Deforestation 1940 to 1983. Telford, C.J. 1926. Third report on a forest survey of Illinois. Illinois Natural History Survey Bulletin 16(l):l-102. U.S. Department of Agriciiltlire. 1982. An inventory of Illinois windbreak needs. Soil Conser- vation Service, Champaign, IL. n.p. Forest Succession in the Prairie Peninsula of Illinois John E. Ebinger, Botany Department, Eastern Illinois University, and William E. McClain, Division of Natural Heritage. Illinois Department of Conservation Presently most of central Illinois is in the Grand Prairie Natural Division (Schwegman 1973), classified as a part of the prairie peninsula of the oak-hickory forest region by Braun ( 1950). as a mosaic of bluestem prairie and oak-hickory forest by Kuchler ( 1964). and as a part of the prairie-deciduous forest ecotone by Davis (1977). At the time of settlement by Europeans, prairie dominated most of Illinois. Forests were common, however, occurring on rough terrain such as moraines and dissected valleys of streams and rivers and as isolated groves on the flat to gently rolling prairie. During postglacial times, the vegetation of Illinois changed extensively (King 1981). Pollen diagrams from the prairie peninsula in Illinois record the climatically related vegeta- tion shifts that have occurred since the late Pleistocene. The pollen record for Chatsworth Bog. Livingston County, in the center of the prairie peninsula, suggests that a mosaic of open spruce woodlands and tundra existed there from 14700 to 13800 BP This cover type in turn was replaced by an ash/tundra as.sem- blage that reflected the slowly increasing temperatures of the late-glacial from 13800 to 1 1600 BP After 1 1600 BP pollen from deciduous trees and shrubs increased dramati- cally, starting with cool-climate species (birch, hazel, black ash) and followed by such warm- tolerant taxa as elms, oaks, and hickories. By 8300 BP, prairie dominated the area as indi- cated by a dramatic decrease in tree pollen and a corresponding increase in the amount of pollen from herbaceous plants. Oak pollen was still present, however, suggesting that prairie vegetation was probably common on the drier flat uplands while the lowlands and river valleys retained their forest cover. These open expanses of prairie with savanna and forest communities restricted to the more dissected lands were what the early European settlers found when they entered the prairie peninsula of Illinois in the early 1800s. The presettlement distribution of the major vegetation types in Illinois (prairie, savanna, and forest) was determined largely by firebreaks such as lakes and rivers and by topographic relief that controlled the frequency and intensity of fire (Gleason 1913; Wells 1970; Grimm 1984). Glea.son (1913) found that forests were more extensive on the east side of firebreaks, while prairie tended to be more extensive on the west side. This distribution pattern was the result of prevailing westerly winds that carried fires to the western sides of firebreaks, thus encouraging the development of prairies. In contrast, the eastern sides were protected from fires, and forest developed at these locations. PRESETTLEMENT FORESTS In presettlement times, according to survey records of the General Land Office, prairie occupied 61.2% of Illinois and forest and savanna accounted for 38.2% (Iverson et al. 1989). In general, prairie vegetation was most common on flat to gently sloping ground; savanna and forest were most common in dissected areas. The segregation of forest, savanna, and prairie on the basis of topography apparently occurred because dissected land- scapes do not readily carry fire. For the most part, these dissected landscapes have well- developed drainage systems that support permanent or temporary streams, which serve as firebreaks. In addition, fires in hilly areas tend to move up slope relatively rapidly due to rising convection air currents, but convection currents work against fires when they move down hill, not uncommonly causing them to burn themselves out. A great deal of vegetation information can be obtained from survey records of the General Land Office (Bourdo 1956). The job of the surveyors was to establish a grid system of township, range, and section lines by the 37.5 376 llinois Natural Hisior> Survey Bulletin Vol. 34 An. 4 placement of section and quarter section comer posts. In prairie and marsh areas, only posts were used. In timbered areas, however, two (or four) witness trees were blazed, and the distance and direction of these trees from the comer posts were recorded along with their species and estimated diameter at breast height (dbh). Because the placement of the corner posts and the selection of witness trees were essentially random, the principles of the distance method (Cottam and Curtis 1956) can be applied to the witness tree data and the composition and tree density of the presettle- ment savannas and forests determined. In Illinois, several researchers have used survey records of the General Land Office to determine the extent, composition and densities of tree species for various counties. Some of their studies are summarized here and indicate the extent and composition of the presettlement vegetation of the prairie peninsula. Kilbum (1959) found that the original forest in Kane County consisted largely of oak openings composed of pure bur oak or bur/ white oak stands. Lowlands and swamp forests were found along rivers and streams, but a more mesic forest occurred on the heavier soils of the Big Woods area. Overall, three-fifths of the county was prairie. Topography accounted for most of the vegetation pattern: level areas were in prairie vegetation; protected ravines, valleys, steep bluffs, and hills were largely forested. Overall. 87% of the witness trees recorded by the surveyors were oaks and hickories. In Lake County, the situation was similar. Oak and hickory species accounted for 95% of the trees recorded (Moran 1976). In this county, however, savanna was the dominant vegetation type, occupying 51% of the area. It was found mostly on rolling uplands that were frequently broken by small wetlands or streams; bur oak was by far the most common species with black and white oaks in lesser numbers. Prairie, wet prairie, and marsh occupied ?y/c of the county while forests occurred in the remaining 16%. For the most part, prairies were situated on flat terrain and forests were restricted to areas of rough topography or where natural firebreaks afforded some protection. In McLean County, located in west- central Illinois, the presettlement vegetation was 89.5% prairie. 5.4% savanna. 1.8% open forest, and 3.3% closed forest (Rodgers and Anderson 1979). The forested areas occurred on the more rugged topography associated with rivers, streams, and glacial moraines. White and black oaks were the most numerous sF>ecies recorded, but in the closed forests (273 trees/ ha) the more mesic species (i.e., sugar maple, elm. red oak. buckeye) accounted for about one-third of the trees present. These more shade-tolerant, mesic species, which for the most part are fire-sensitive, occupied sheltered ravines and areas adjacent to streams where fires occurred infrequently. In contrast, the relatively shade-intolerant oaks, which depend on periodic fires to maintain their dominance, were more common on less dissected uplands. In adjacent Mason County, similar results were obtained (Rodgers and Anderson 1979). Located in the Illinois Ri\er Sand Area Section (Schwegman 1973). on soils developed from deep sand deposits laid dow n by glacial meltwater during the Pleistocene ( Willman and Frye 1970). prairie was the dominant vegeta- tion type, occupying 67.7% of the county. Savanna (14.4%) and forest (13.3%) occurred on most of the remaining land and 4.6% was covered by lakes and swamps. The dominant tree species in the presettlement forests and savannas were shade-intolerant, fire-tolerant black and blackjack oaks. In the closed forests (263 trees/ha), the oaks and hickories were still the most numerous species. The more mesic. shade-tolerant. fire-sensiti\e tree species (i.e.. sugar maple, elm. walnut) v\ere also found in the closed forests, particularly in areas of rough topography. In Douglas County, near the southern edge of the Grand Prairie Natural Division (Schwegman 1973). prairie was the most widespread plant community (85%). Closed forest, which was generally restricted to the major river systems, accounted for the remain- ing 15%. These forests v\ere dominated b\ white and black oaks and hickories, species that accounted for 70% of the w itness trees re- corded by the surve>ors. Mesic. shade-tolerant, fire-sensitive species were present but restricted to areas of rough topographx and ri\ er \ alleys (Ebinger 1986a). Prairie was the most widespread vegeta- tion type (60%) in Coles Count\. the southern half of which is located on the Shelbyxille Moraine, the terminal moraine of Wisconsin glaciation. Prairie was most common on the flat to gently rolling uplands in the northem and April 1991 Symposium Proceedings; Our Living Heritage 377 central parts of the county. Forests, which accounted for most of the remaining 40% , were restricted to the rough topography of the terminal moraine and to the valleys of the Kaskaskia and Embarras rivers. More than 80% of the witness trees recorded were oaks and hickories, with white, black, and red oaks most numerous. Again, more mesic species were restricted to rough topography (Ebinger 1987). Information extrapolated from the records of early surveyors indicates that prairie vegetation dominated most of Illinois in presettlement times and was found on the flat to gently rolling uplands throughout most of the state. Savannas and forests, in contrast, were more common in rough topography, especially in the driftless areas, along major waterways, and where morainal systems provided topo- graphic relief. For the most part, savannas developed on sites where the frequency of fire was reduced, thereby permitting the establish- ment of fire-tolerant tree species (Anderson 1970; Anderson and Anderson 1975: Grimm 1984; Anderson and Brown 1986). Forests, particularly closed forests, developed in places of rough relief, in river valleys, and in other protected areas where fires were less likely to occur. Oaks and occasionally hickories dominated the open savannas. In the forests, oaks and hickories were also the dominant species, but more mesic. shade-tolerant, fire- sensitive tree species were common forest components. Furthermore, the transition from forest to prairie varied from being rather abrupt in some locations in the prairie peninsula to others where savannas formed a broad transi- tion between forest and prairie (Nuzzo 1986). This transition was probably determined by topographic relief, firebreaks, fuel loads, and other edaphic and climatic factors that con- trolled the frequency and intensity of fires. PRESENT SUCCESSION TRENDS During the past century and a half of agricul- tural development, periodic fires have ceased in the prairie peninsula, and the oak savannas and open oak forests on the uplands have become closed-canopy forests. As a result, these woodlots have been changing to forests domi- nated by such mesic, shade-tolerant, fire- sensitive species as sugar maple, American and red elms, white and green ashes, and ironwood (Anderson and Adams 1978; Adams and Anderson 1980; Ebinger 1986b). In particular, sugar maple has increased in importance in most Illinois forests (Iverson et al. 1989). If this trend continues, many of the oak-hickory forests, their understories, and the wildlife that depends upon them will be in serious trouble in the near future. Even the best quality oak-hickory communities are appar- ently undergoing an irreversible change as sugar maple and other mesic, shade-tolerant species replace many of the original forest components. Almost no work has been done concerning methods to reverse this trend, and the problem now concerns many ecologists and managers of natural areas. Many of the better quality forests that presently exist in the prairie peninsula have been surveyed during the past thirty years. In a few of them, sugar maple is not an important component, though other mesic species are sometimes common. At Walnut Point State Park in Douglas County (Ebinger et al. 1977), sugar maple is rarely encountered, and oaks and hickories are by far the most numerous species. In the forests and savannas of the Kankakee Sand Area Section (McDowell et al. 1983) and the Illinois River Sand Area Section (Rodgers and Anderson 1979) oaks dominate and mesic species are rarely encountered. In most of the stands studied, however, mesic species, particularly sugar maple, are relatively important components. These mesic species are also well represented in the seedling and sapling categories and in the smaller diameter classes. Oaks and hickories, in contrast, are poorly represented in these categories. Mesic, shade-tolerant, fire-sensitive species are common components of many recently surveyed forests in the prairie penin- sula. Two "prairie grove forests'" in Champaign County have been surveyed at various times in the past, and sugar maple is an important component in both. In Trelease Woods (Boggess 1964; Pelz and Rolfe 1977), sugar maple dominates the seedling and sapling categories as well as most of the diameter classes. Similar results were obtained for Brownfield Woods by Boggess and Bailey (1964) and Micelietal.( 1977). An inventory of the woody vegetation of Funks Forest Natural Area in McLean County was conducted by Boggess and Geis (1966). This forest is an example of a mesophytic forest that is transitional between the upland oak-hickory cover type and the "prairie grove 378 llinois Natural Historj' Survey Bulletin Vol. 34 An. 4 forest." Sugar maple, the dominant species in Funks Forest, is followed closely by white oak and elm. Sugar maple and white oak. however, represent two distinct age classes. White oak, which predominates in the 30-inch-diameter class, is a "pioneer" species: and sugar maple, which predominates in the 16-inch-diameter class, has perhaps been increasing steadily in importance during the past century. One recently documented example of the increase in importance of sugar maple is at Baber Woods Nature Preserve in Edgar County. This 16-ha forest is located on the flat to gently rolling ground just north of the Shelbyville Moraine, the terminal moraine of Wisconsin glaciation. Two decades ago, McClain and Ebinger (1968) reported that sugar maple ranked second in importance in the woods and dominated the seedling, sapling, and smaller diameter classes. In a more recent survey of the same area, Newman and Ebinger (1985) found that this trend had continued. Sugar maple was now first in importance, and the number per acre had almost doubled. Further, sugar maple continued to dominate the seedling and sapling categories and accounted for nearly half of the individuals in smaller diameter classes. Sugar maple and oaks represent two distinct age classes in Baber Woods, as shown in Figure 1. These curves show that oaks predominate the larger diameter classes and suggest that these species have been an important forest compo- nent for an extended period of tune. Sugar maple, in contrast, predominates the smaller diameter classes and has probably been increasing steadily during the past century. The large number of sugar maple .seedlings, saplings, and smaller diameter trees suggests a continuation of this trend. Table 1 indicates when sugar maples began to increase in importance in Baber Woods. In nearly every quadrat, sugar maple increased in number, size, and importance from 1965 to 1983. In addition, the number, size, and importance of sugar maple decreased from the northwestern comer of the woods, becoming smaller and less common toward the southeast- em comer. This pattem suggests that sugar maple probably occurred in the ravines that exist just to the north and west of the u oods, where in pre.settlement times it was probably protected from fire due to the rough topogra- phy. With the cessation of fire, this fire- sensitive species has been able to invade the upland forests that still exist in the area. Another indication of the increase of sugar maple in Baber Woods is the distribution of this species and the oak species by diameter classes for the 1965 and 1983 sur\eys (Table 2). Sugar maple increased in all diameter classes between 1965 and 1983. particularly in two diameter classes. 10-19 and 20-29 cm. Sugar maple showed an overall increase of nearly 30 trees per hectare between the two surveys. In contrast, oak species decrea.sed in numbers, dramatically so in the lower diameter classes, with increases occurring only in classes 60-69 cm in diameter and above (Table 2). Overall, species density increased in the woodlot. from 258.6 stems/ha in 1965 to 277.3 stems/ha in 1983. Most of this increase is due to sugar maple and other mesic species that are tolerant of shade and sensitive to fire. Presently the oaks are common in the larger diameter classes because of recruitment from the smaller diameter classes. Oak reproduction is sparse (McClain and Ebinger 1968: Newman and Ebinger 1985). and as the veteran trees die. fewer oaks are available to fill the canopy gaps. In contrast, sugar maple, w ith its high gap- Total basal area (square feet) 250- All species 15 20 25 30 Diameter class (inches) Figure 1. Smooth cur\es of basal area b\ diameter class for sugar maple, all oak species combined, and all species combined at Baber Woods, Edgar Countv. Illinois. Source: Ebinaer 1986b. 40 April IWI Symposium Proceedings: Our Living Heritage 379 phase replacement potential, is able to take advantage of these canopy openings (Ebinger 1986). " Within Baber Woods are a number of large open-grown white oaks. In a walk- through survey conducted during the early spring of 1990, twenty-six large, open-grown white oaks were observed. All have open, round crowns and large lower branches, some v\ ithin 4 m of the ground. They are probably remnants from a time when this forest was an open, upland savanna. The average diameter of these open-grown white oaks is 101.6 cm dbh, and two that had died recently were cut and aged at .313 years. Both had fire scars at 65 and 77 years, indicating that in the past fires were probably common in the area. Five other oaks that had died recently were also cut and aged. Table 1. Distribution of sugar maple in Baber Woods Nature Preserve, Edgar County. Illinois, for the surveys of 1965 (McClain and Ebinger 1968) and 1983 (Newman and Ebinger 1985). The following int'omiation is given for each quadrat ( 1 ha): the number of stems present (above 10 cm dbh), the number of stems exceeding 40 cm dbh, the average diameter (cm), and the importance value (relative density and relative dominance) for sugar maple. Highest possible importance value is 200. The northern edge of the woods is represented in quadrats 1 through 4. 380 Illinois Natural History Survey Bulletin Vol. 34 An. 4 These were forest-grown trees with straight trunks, no low branches, and an average diameter of 68.2 cm. They varied in age from 140 to 158 years, with an average age of 148 years. In contrast were the increment cores obtained from 30 sugar maples in various parts of the woodlot. Those from the northwestern part of the woods, where the largest individuals occurred, averaged 44.7 cm dbh and had an average age of 107.6 years. Sugar maples from the northeastern and southeastern comers of the woodlot were smaller and younger (Table 3). The data suggest that before European settlement, the area now known as Baber Woods was an open, white oak savanna maintained by periodic fires. This community was probably parklike with an understory of prairie grasses and forbs. With the cessation of fire, the number of seedlings increased and began to fill the gaps in the canopy between the large open-grown oaks. As shade increased, moisture levels within the forest probably increased, creating a habitat for more mesic, shade-tolerant, fire-sensitive species such as sugar maple. LITERATURE CITED Adams, D., and R.C. Anderson. 1980. Species response to a moisture gradient in central Illinois forests. American Journal of Botany 67:381-392. Anderson, R.C. 1970. Prairies in the prairie state. Transactions of the Illinois State Academy of Science 63(2):2 14-221. Anderson, R.C. and D.E. Adams. 1978. Species replacement patterns in central Illinois white oak forests. Pages 284-301 //; P. Pope, ed. Proceedings of the Central Hardwood Forest Conference II. Purdue University, IN. Anderson, R.C, and M.R. Anderson. 197,^. The presettlement vegetation of Williamson County, Illinois. Castanea 40:345-363. Anderson, R.C, and L.E. Brown. 1986. Stability and instability in plant communities following fire. American Journal of Botany 73:364-368. Boggess. W.R. 1964. Trelease Woods. Champaign County. Illinois: woody vegetation and stand composition. Transactions of the Illinois State Academy of Science 57(4):26l-271. Bogcess. W.R., AND L.W. Bailey. 1964. Brownfield Woods. Illinois: woody vegetation and changes since 1925. American Midland Naturalist 71:392-401. Boggess, W.R.. and J.W. Geis. 1966. The Funk Forest Natural Area, McLean County, Illinois: woody vegetation and ecological trends. Trans- actions of the Illinois State Academv of Science 59(2): 1 23-1 33. Bolrdo, E.A. 1956. A review of the General Land Office Survey and of its use in quantitative studies of former forests. Ecology 37:754-768. Brain. EL. 1950. Deciduous forests of eastern North America. Blakiston, Philadelphia. PA. 5% p. CoTTAM, G., and J.T. Cl'RTIS. 1956. The use of distance methods in phytosociological sampling. Ecology 37:271-287. Davis, A. 1977. The prairie-deciduous forest ecotone in the upper Middle West. Annals of the Association of American Geographers 67:204-213. Ebinger, J.E. 1986a. Presettlement vegetation of Douglas County, Illinois. Erigenia 7:15-22. Ebinger. J.E. 1986b. Sugar maple, a management problem in Illinois forests? Transactions of the Illinois State Academy of Science 79( 1 & 2):25-30. Ebinger, J.E. 1987. Presettlement vegetation of Coles County. Illinois. Transactions of the Illinois State Academy of Science 80( 1 & 2): 15-24. Ebinger, J.E., P.E. Phillippe, and L.R. Phillippe. 1977. Woody vegetation of an upland forest in Douglas Countv, Illinois. Castanea 42:285-293. Table 3. Tree rings and diameters (dbh) of sugar maples at selected sites in Baber Woods Nature Preserve, Edgar County, Illinois. April 1991 Symposium Proceedings: Our Living Heritage 381 Gleason. H.A. 1913. The relation of forest distribution and prairie fires in tine Middle West. Torreya 13:173-181. Grimm. E.C. 1984. Fire and other factors controlling the big woods vegetation of Minnesota in the mid- nineteenth century. Ecological Monographs 54:291-311. IvERSON. L.R., R.L. Oliver. D.P. Tlcker. P.G. RissER. CD. Burnett, and R.G. Ravburn. 1989. Forest resources of Illinois: an atlas and analysis of spatial and temporal trends. Illinois Natural History Sun'ey Special Publication II. 181 p. KiLBLRN. P.D. 1959. The forest-prairie ecotone in northeastern Illinois. American Midland Naturalist 62:206-217. King. J.E. 1981. Late Quaternary vegetational histoid of Illinois. Ecological Monographs 51:43-62. KucHLER. A.W. 1964. Manual to accompany the map. potential natural vegetation of the contermi- nous United States. American Geographical Society Special Publication 36. American Geographical Society. New York. 39-1-1 16 p. McClain. W.E.. AND J.E. Ebinger. 1968. Woody vegetation of Baber Woods. Edgar County. Illinois. American Midland Naturalist 79:419-428. McDowell. B.. J. Newman, and J.E. Ebinger. 1983. Survey of the woody vegetation of the Kankakee Sand .Area Section of Indiana and Illinois. Proceedings of the Indiana Academy of Science 93:187-193. MiCELi. J.C, G.L. RoLf E, D.R. Pelz. and J.M. Edgington. 1977. Brownfield Woods. Illinois: woody vegetation and change since 1960. American Midland Naturalist 98:469-476. Moran, R.C. 1976. Presettlement vegetation of Lake County. Illinois. Pages 12-18 //; D.C. Glenn- Lewin and R.Q. Landers, Jr.. eds. Proceedings of the Fifth Midwest Prairie Conference. Iowa State University. Ames. Newman. J.A., and J.E. Ebinger. 1985. Woody vegetation of Baber Woods: composition and change since 1965. Pages 178-180 (/; J.O. Dawson and K.A. Majerus. eds. Fifth Central Hardwood Forest Conference. Society of American Foresters Publica- tion 85-05. Department of Forestry. University of Illinois at Llrbana-Champaign. Nuz/o. V.A. 1986. Extent and status of midwest oak savanna: presettlement and 1985. Natural Areas Journal 6:6-36. Pel/. D.R.. and G.L. Rolfe. 1977. Stand structure and composition of a natural mixed hardwood forest. Transactions of the Illinois State Academy of Science 69(4 ):446-454. Rodgers. C.S.. AND R.C. Anderson. 1979. Presettlement vegetation of two prairie peninsula counties. Botanical Gazette 140:232-240. Schwegman. J. 1973. Comprehensive plan for the Illinois Nature Preserves System. Part 2. The natural divisions of Illinois. Illinois Nature Preserves Commission. Rockford. IL. Wells, P.V. 1970. Historical factors controlling vegetation patterns and floristic distribution in the Central Great Plains region of North America. Pages 21 1-234 ill W. Don. Jr.. and J.K. Jones. Jr.. eds. Pleistocene and recent environments of the Central Great Plains. University Press of Kansas. Lawrence. WiLLMAN. H.B.. AND J.C. Frye. 1970. Pleistocene stratigraphy of Illinois. Illinois State Geological Sun.'ey Bulletin 94. 204 p. Effects of Forest Fragmentation on Illinois Birds Scott K. Robinson, Illinois Natural History Survey Abstract. The forests in Illinois are among tiie most fragmented in North America. Most re- maining tracts are small, isolated, and domi- nated by "edge" habitats. Populations of many forest species, especially those that breed in the forest interior, have been declining, and many characteristic forest species do not occur in woodlots below a certain minimum size. Data from small woodlots (<63 ha; 170 acres) in the Lake Shelbyville area of central Illinois suggest that reproductive failure may be at least partly responsible for these trends, especially among the neotropical migrants that breed in Illinois but winter in the tropics. Most nests fail becau.se of brood parasitism by brown-headed cowbirds (Molothrits ater) {16% of all nests of neotropical migrants) or because of nest predation (80% of all nests). Brown-headed cowbirds, which are abundant throughout Illinois, pose a particu- larly severe threat because they lay their eggs in the nests of host species, which go on to raise cowbirds instead of their own young. Parasitized nests in the Lake Shelbyville area averaged 3.3 cowbird eggs per parasitized nest. All 19 wood thrush (Hylocichla miistelimi) nests were parasitized with an average of 4.6 cowbird eggs per nest. Only about 10% of the birds of all species caught in midsummer were juveniles. These data strongly suggest that the reproduction of neotropical migrants in very small woodlots is insufficient to compensate for adult mortality, a result consistent with the population declines observed in the Shelbyville area. Birds nesting in much larger tracts (up to 2.024 ha: 5,000 acres) in the Shawnee National Forest appear to face similar problems. A crew of 14 workers located over 400 nests in 1989 and discovered that cowbird parasitism and nest predation rates were high, even deep in the forest interior. In contrast to studies elsewhere, cowbirds were found throughout each study area, regardless of the proximil> of edges. 0\er 55% of all nests were parasitized and an average of 60% of all nests were destroyed by predators. As in Shelbyville, wood thrushes suffered most from co\a birds: 90% of all nests parasitized and an average of 3.2 cowbird eggs per nest. Other species that suffered high (>70%) parasitism rates were the red-eyed vireo (Vireo oUvaceus) and the scarlet (Pira/ii^a oUvcicea) and summer tanagers {P. riihra). A few species reproduced successfully in spite of the abundance of nest predators and cowbirds. Worm-eating (Helmhheros \ernmorus) and Kentucky warblers {Opnrornis formosus) hide their nests effectively, and for these species young outnumbered adults in midsummer samples of birds caught in mist nests. These results suggest that management decisions will have to take into account differences among species in susceptibility to forest fragmentation. The cowbird situation is more serious than has been anticipated and apparently cannot be solved simply b\ mini- mizing edges as has been proposed elsew here in the Midwest. At least a few species, for example, the wood thrush, may be in serious trouble throughout the Midwest and should receive special management attention. 382 Session Two: Prairies and Barrens The chance to find a pasque-flower is a rif^hl as inalienable as free speech.—Aldo Leopold The first Europeans to see the Illinois country had crossed a vast ocean, snaked their way through a nearly impenetrable mountain range, and forged a path through a thousand miles of dense, primeval forest. They did it \\\\\\ indomi- table spirit and by sheer force of will. Yet when they reached the edge of the eastern deciduous forest, approximated today by the Indiana- Illinois border, they stopped in wonder. Here uas a landscape so different from those w ith which they were familiar that they had no word for it. In time this landscape came to be known as "prairie," a word derived from the French word for meadow. At first, early settlers avoided living on the prairie because the treeless grasslands were thought to be infertile. They did not provide much needed building materials, fuel, and water. Instead, they offered the prospect of menacing prairie fires and how ling winter storms. Soon, however, the settlers realized that prairie made excellent cropland, especially after John Deere invented the moldboard plow that allowed virgin prairie soil to be broken. The wild prairies became cropland at an astonishing rate—approximately 3.3% per year. Over 300.000 people settled on the prairie during the decade of the 1830s. and by 1860 nearly all the prairies had disappeared. At least 23 different kinds of prairies are found in Illinois—add barrens, savannas, and glades and the list increases to over 30. These various prairies once occupied nearly 22 million acres of the state. Today they are confined to about 3,000 acres, less than O.OWc of their original extent. Unfortunately, it is easier to find examples of the prairie's influence in the "prairie" state—Prairie Street. Prairie State Games. Prairie Farms Dairy. Prairieview Estates. Prairie Technology—than it is to find an actual prairie. Prairie remnants persist, however, along railroad lines, in pioneer cemeteries, even on the grounds of industrial complexes, growing in a forgotten comer of some storage yard yet to be developed. Over 200 species of plants characteristi- cally inhabit Illinois prairies. Although this number is relatively low compared with a typical undisturbed woodland, a small prairie remnant—as little as five acres—can be surprisingly diverse with more than 120 species of plants. All present-day Illinois prairies, however, are incomplete, fragmented ecosystems and lack the large herbivores that were so important in their development. What if Illinoisans had had the foresight to preserve only 100 square miles of virgin prairie in central Illinois? What a tremendous natural resource and botanical laboratory that would be today! Inevitable though the destruc- tion of the prairie may have been, it is truly unfortunate that prairies will be visualized by future generations as isolated pockets of native vegetation, persisting in a world that passed them by. Ironically, the French word for meadow, so incongruous when applied to this once vast grassland, now seems totally appropriate. The session opened with a broad historical perspective of the tallgrass prairie. The papers that followed focused tightly on two aspects of that prairie—the remnant- restricted prairie and savanna insects of the Chicago region and the response of prairie birds to habitat fragmentation. .^8.1 Illinois Prairies: A Historical Perspective Roger C. Anderson, Department of Biology, Illinois State University The grasslands of central North America originated in the Miocene-Pliocene transition, about 7-5 million years before present (YRBP) and were associated with the beginning of a drying trend. The Miocene uplift of the Rocky Mountains created a partial barrier between moist Pacific air masses and the interior portion of the continent. The spread of the Antarctic ice sheet, by tying up atmospheric moisture, also contributed to increased aridity. Woody plants are generally less well adapted to drought than most grass species, and the spread of grasslands con.sequently occurred at the expense of forests. As the grassland expanded, numbers of grazing and browsing animals increased, an indication that the association of grasses and grazers occurred over a long period of time (Stebbins 1981: Axelrod 1985). The prairies of Illinois are part of the central grassland, a large triangular-shaped area that has its base along the foothills of the Rocky Mountains from the Canadian provinces of Saskatchewan and Manitoba southward through New Mexico into Texas. The apex of the triangle, the prairie peninsula (Transeau 1935), extends eastward into the Midwest and includes the prairies of Illinois. Iowa. Indiana. Minnesota, Missouri, and Wisconsin with scattered outliers in southern Michigan. Ohio, and Kentucky. Because the Rocky Mountains intercept moist air masses moving westward from the Pacific Coast, the grassland lies in the partial rain shadow to the east. From west to east within the central grasslands, annual precipitation increases from 23-38 cm to 75-100 cm and becomes more reliable: potential evapotranspiration decreases, the number of days with rainfall increases, and periods of low humidity and periodic droughts in July and August decrease (Risser et al. 1981 ). Associated within this climatic gradient is a shift in the grassland species dominating the vegetation. Ecologists traditionally have separated the central grassland into three major west-east divisions. The arid western shortgrass prairie is dominated by such species as buffalo grass {Buchloc dactyloides). blue grama {Boiiteloua i;racilis). and hairy grama (6. hirsiiia) that reach heights of only 30-45 cm. The mixed- grass prairie occupies the middle sector of the central grassland and is dominated by grasses that are 60-120 cm tall, including little bluestem {Schizachyrium scaparium). needle- grasses (Stipa spartea and 5. cnmara). and wheatgrasses (Agropyron smithii and .4. dasysrachyum). The prairies of Illinois are in the eastern portion of the remaining division of the central grassland, the tallgrass prairie (Figure 1 ). In this area of relatively high rainfall, the dominant grasses on mesic sites include big bluestem {Andropogon gerardi). Indian grass {Sorghustruni nutans), and switchgrass (Panicum virgatiim)—grasses that reach heights of 1.8-3.6 m. On poorly drained sites supporting wet prairies, prairie cordgrass {Spartina pi'ctinahi) and blue joint grass (Calcimagrosris icinadensis) are dominant species: little bluestem and sideoats grama (Bouteloiia ciirtipcndiilu) are important grasses on dry sites (Weaver 1954: Risser et al. 1981: Bazzaz and Parrish 1982). Figure 2 indicates how these major grass species follow a soil moisture gradient. Illinois prairies, which dominated about 609r of the state prior to the e\tensi\ e settle- ment and alteration of the landscape b> Europeans, developed since the last glacial advance. According to King ( 1981), as the last of the Wisconsinan age ice sheet retreated from the northeastern portions of the state, mesic deciduous forests dominated most of the landscape. A drv ing and w amiing trend began about 8.700-7,900 ^RBP. and prairie began to replace deciduous forests ui southern Illinois. Prairie inllux into central Illinois occurred 384 April lyyi Symposium Proceedings: Our Living Heritage 385 about 8,300 YRBP and concomitantly oak-hickory forest began to replace niesic forest in the northern portion of the state. Prairies occupied much of the state during the Hypsitherma! Period (8,000-6,000 YRBP), which was the hottest and driest part of the Holocene. The chniate became cooler and more moist following the Hypsithermal, but prairie stabilized throughout much of Illinois (King 1981). Because of increased rainfall and reduced evapotranspiration, the climate is increasingly favorable for the growth of trees from west to east in the central grassland. Consequently, in Illinois and the rest of the prairie peninsula, the average climate for approximately the past 5,000 years appears to have been more favor- able for forest than for grassland. However, this region has had periodic droughts during which the forest retreated and the grasslands advanced or were maintained. To understand factors influencing the persistence of grasslands in this region, we must consider the extremes of climate and not the average. Britton and Messenger (1970) suggested that the droughts that are most detrimental to woody species are those that do not permit deep recharge of soil moisture during the winter months. On soils without drainage restrictions, trees generally root at greater depths than grasses and rely on moisture stored deep in the soil during droughty periods in midsummer. Interestingly, Britton and Messenger ( 1970) presented data showing that areas of the Midwest that did not experience deep soil moisture recharge during the drought of 1933-1934 approximately corresponded to the prairie peninsula (Figure 3). Relalive AbuiulaiKe Mesic Moisture Gradient Figure 2. Generalized distribution of major grass species across a soil moisture gradient: ( 1 ) sideoats grama, Boiiieloua cunipciuhtUi: (2) little bluestem, Schizachyiiiim scopciriiim: (3) Indian grass, Sori;has- trum nutans: (4) big bluestem, Anclropof;i>n geradi; (5) switchgrass, Panicum virgatum: (6) bluejoint grass, Calamagrostis canculensis: (7) prairie cordgrass. Spunina pecunaui. Adapted from Parrish and Bazzaz 1982. Figure 1 . Presettlement distribution of the tallgrass prairie. Adapted from National Geographic (1980) 157(1 ):43. Figure 3. Area in which complete recharge of soil moisture did not occur between the summer of 1933 and the summer of 1934 is shown in dark grey; light grey indicates the area of complete recharge. From Britton and Messenger 1970. 386 llnois Natural Hist()r>' Survey Bulletin Vol. 34 An. 4 Ecologists generally recognize that climate is the most important factor influencing the distribution of vegetation. However, most ecologists believe that prairie vegetation in the eastern United States would have largely disappeared during the past 3,000 years had it not been for the nearly annual burning of the prairies by the North American Indians and the prairie fires set by lightning (Komarek 1968). The role of Indians in maintaining the prairies and the reasons they burned these grasslands have been discussed and documented by various authors (e.g., Stewart 1951, 1956: Curtis 1959; Pyne 1986). Although many woody species, for example, oaks (Qiiercus spp.), readily resprout after being top-killed by fire, prairie species are generally better adapted to burning than are most woody plants. The adaptation that protects grasses and forbs from fire is their annual growth habit: the plant dies back to its under- ground organs each year, exposing only dead material above ground (Gleason 1922). Prairie fires become very hot above ground and on the surface of the soil (83 to 680 C) (Wright 1974: Rice and Parenti 1978) but because they move quickly and soil is a good insulator, little heat penetrates the soil. The same adaptation that protects prairie plants from fire also protects them from drought and grazing. Growing points beneath the surface of the soil permit regrowth after intense grazing and protect perennating organs from desiccation during periods of drought or from fire at any time of the year (Gleason 1922: Tainton and Mentis 1984: Anderson 1982,1990). Grasses generally produce more biomass annually than can be decomposed in a year. This production of excess herbage probably evolved in response to grazing: however, the productivity of grasslands declines w hen excess pkint litter is not removed by fire or grazing (GoUey and Golley 1972). Thus, grasslands evolved under conditions of periodic drought, fire, and grazing and are adapted to all three (Owen aiid Wiegert 1981: McNaughton 1979, 1984: Anderson^ 990). In presettlement Illinois, the vegetation was primarily a shifting mosaic of prairie, forest, and savanna that was largch controlled by the frequency of fire luider climatic condi- tions that were capable of supporting any of these vegetation types. The frequency of fire was largely determined by topography and the occurrence of such natural firebreaks as waterways and dissected landscapes. Fires carry readily across landscapes that are level to gently rolling, but in hilly and dissected landscapes the spread of fire is more limited (Wells 1970: Grimm 1984). Fire tends to carry well uphill because rising convection currents encourage its spread. But as fire moves down slopes, the convection currents tend to retard it by rising upward and working against the downward direction of the moving fire. The importance of waterw ays in deter- mining the distribution of forest and prairie in presettlement Illinois was demonstrated by Gleason (1913) through the use of the Govern- ment Land Office Records for selected Illinois counties. He found that prairies were more associated w ith the west sides of streams and bodies of water than w ith the east sides, and forests were generally found bordering the east sides. Gleason attributed this pattern to prevailing westerly winds that carried fires from west to east: the west sides of w aterways. therefore, burned more frequenth than the east sides. Forests were most abundant in presettle- ment Illinois in the northeast Morainal Section (Schwegman 1973) and in the three unglaciated areas of Illinois (driftless area of Jo Daxiess and Carroll counties in northwest Illinois, Calhoun County and portions of Pike Count) in west-central Illinois, and the far southern portion of the state) (Figure 4). In these areas, the dissected nature of the topography and/or the presence of waterways decreased the frequency of fire and encouraged the grow th of forests and savannas. Similarly, the lUinoian till plain, which is older and more dissected than the Wisconsinan till plain, supported more forest than the Wisconsinan till plain, espe- cially in the southern portion (Figure 4). The relationship between topographic relief and vegetational patterns in Illinois has been recently reexamined. Using a map showing the distribution of prairies and timber (forest and sasanna) for Illinois, based on the Government Land Ot'fice Records (.Anderson 1970). and a map of the axerage slope range for the state (Fehrenbacher et al. 1968). Anderson ( 1991 ) determined the simultaneous occurrence of slope categories and vegetation. Most of the prairie \egetation (82.3'^f ) occurred on land- scapes with slopes of 2-4*^; only 23.0^ of the timbered land, usually on fioodplains. was associated w ith this slope category. In contrast. April IWl Symp()^ium Proceedings: Our Living Heritage 387 ll'^/c of the timbered land occurred on sites that had slopes greater than 4% (4-7% slope = 35.2% timber and >7% slope = 41.8% timber) (Figure .5). Iverson ( 1988) also showed that presettlement forests were positively correlated with sloping landscapes. The relationship between vegetational patterns and topography is illustrated by the presettlement vegetation of McLean County, which is located in the Grand Prairie Division (Schwegman 1973). That relationship is shown in Figure 6 (Rogers and Anderson 1979). Prior to settlement by Europeans, the county was 90% tallgrass prairie, which occupied relatively level landscapes. Savannas and open forests that were dominated by relatively shade- intolerant but moderately fire-resistant oaks (burr. Qiicrciis macrocaipci: white, Q. alha: and black. Q. velutina) occurred on slopes and Driftless Kansan Unglaciated Unglaciatcd Figure 4. Areal distribution of the domin;mt till formations and unglaLiated portions ol Illinois. Adapted from Willman and Frye 1970. ridges of glacial moraines. These areas were subject to periodic fires but less frequently than the prairies. Sheltered areas, such as ravines and stream valleys, contained oaks and hickories but also a high component of meso- phytic, shade-tolerant, and fire-susceptible tree species—elms (Ulmiis spp.), ashes {Fni.xiniis spp.), and maples (Acer spp.). The presettlement prairies of Illinois were drastically altered by the influx of European settlers who converted essentially all of the prairie lands to agriculture. The earliest settlers entered the unglaciated southern portion of the state. This was a familiar landscape for these people who were mostly hunters and trappers from forested regions of Tennessee, Kentucky, and West Virginia. As they migrated north- ward, they followed the fingerlike traces of forest along the major waterways and initially avoided the larger tracts of prairie. For a variety of reasons, the larger tracts of prairie were avoided in favor of smaller tracts of prairie adjacent to waterways and timber. The settlers needed water for their livestock and to turn waterw heels, and timber was needed for fuel and building materials. In addition, the large tracts of prairie exposed the settlers to the force of winter storms. Timber was considered such an important commodity on the prairie that counties were not allowed to form as govern- mental units until residents could demonstrate that they had access to timber to support development (Prince and Burnham 1908). Ironically, some of the earliest settlers believed that prairie soils were infertile. They had been farniliar with life in the forest and thought that soil incapable of supporting trees would not be productive for crops. Further- more, turning over the thick prairie sod was an almost insurmountable obstacle to early prairie fanners until John Deere invented the self- scouring steel plow in 1836. Even after settlers had learned of the fertility of the prairie soil and could rai.se large crops, many of the larger tracts of prairie remained unsettled because the lack of transportation to get crops to distant markets inhibited expansion onto the prairie. With the coming of the railroads in the 1 8.50-1 8A{)s, however, prairies were rapidly converted to cropland (Anderson 1970). As the prairies were converted to an agricultural landscape, fires, which had swept nearly annually across the prairie in presettle- ment times, were actively stopped by settlers 388 Illinois Natural Hisior) Survey Bulletin Vol. 34 Art. 4 who viewed them as a threat to economic security. According to Gerhard (1857: 278), "The first efforts to convert prairies into forest land were usually made on the part of the prairie adjoining to the timber. . . . three furrows were ploughed all round the settle- ments in order to stop the burning of the prairies . . . ; whereupon the timber quickly grows up." The settlers also indirectly stopped the fires by creating plowed fields and roads that acted as firebreaks. Cessation of these nearly annual prairie conflagrations furthered the demise of the prairies, and many of them were converted to forests or savanna by invading tree species, the distribution of which was no longer restricted by periodic fires. Prairies continued to persist along railroad rights-of-way. Railroads had been in place before the landscape was exten- sively disturbed and the rights-of-way. which usually extended for 100 feet on either side of the track, were fenced to keep off livestock. In addition, the rights-of-way were managed with fire. Those fires along with many accidental fires prevented the invasion of woody species and exotic weeds. In the last 10 to 20 years, however, many of the remnant prairies along railroads have disappeared because herbicides are used to manage rights-of-way rather than fire. Then too, abandoned rights-of-way. which often contained the only example of native prairie vegetation in areas as large as a county, have frequently been purchased by an adjacent landowner and converted to cropland. Within Illinois, tallgrass prairie was the dominant grassland community. Variation in topography, drainage patterns, and soil texture resulted in a variety of prairie community Figure 5. The distribution ol native forest-savanna vegetalioti and prairie (lell) compared to average slope categories (right) in Illinois. Native prairie vegetation is shown as black; nati\e foresl-savannah vegetation is shown as white. A slope of 2—4% is shown as white, 4-7% as stripes, and >7 1 9 trees per acre but < 40 trees per acre Closed forest (3.3%) > 40 trees per acre Figure 6. Presettlement vegetation of McClean County, Illinois, in relaiion to topography about 1820. Adapted t'rom Anderson 1990. 390 linois Natural Histor> Survey Bulletin Vol. 34 Art. 4 with cool-season domestic grasses. The cool season domestic grasses, such as orchard grass {Dactylis glonmieratiis) and smooth brome (Byiimiis iiwrmis), provide forage during the early and late (cool) portions of the growing season. The warm-season prairie grasses, which maximize growth in July and August, produce a high-quality forage in the middle of the summer when the productivity of the cool- season species is low. As a result, cattle are provided with abundant, good-quality forage throughout the growing season. It is interesting to note that such cool- season grasses as the exotic Kentucky blue- grass (Poa pratensis) were favored over native grass species by the European settlers as forage for livestock. Bluegrass provided forage a month earlier in the spring and a month later in the fall than the native species and was favored for this reason (Prince and Bumham 1908). Because the native grasses had evolved under a system of intermittent grazing pressure, they were eliminated when exposed to continuous grazing. After a couple of years of continuous grazing, native species declined, and the Kentucky bluegrass invaded and dominated. In Illinois, the tallgrass prairie ecosystem is gone. Yet, the interest in preserving the remaining remnant prairies is strong, including the efforts of such private groups as the Grand Prairie Friends and The Nature Conservancy and such governmental agencies as the Illinois Department of Conservation and the Depart- ment of Transportation. Plantings of prairie grasses now diversify the vegetation along many interstate highway rights-of-way. An increasing number of native prairie forbs. the nongrass plants cnowers") of the prairie, and prairie grasses are being sold by commercial nurseries and seed growers. These forbs include blazing star (Liatris spp.). purple cone flowers (Echinacea pallichi and E. piirpiirea), yellow cone flower (Ralihicki piniuita), and others. These efforts ensure that future generations of Illinoisans, like the earliest visitors to the state, will have the opportunity to observe prairie life and be inspired by the pleasant colors of tall pi;.airie grasses in the fall and shooting stars (Doclccatlicoii media) and lavender phlox [Plilox pilnsa) in the spring. LITERATURE CITED Anderson. R.C. 1970. Prairies in the prairie state. Transactions of the Illinois State Academy of Science 63(2):214-221. Anderson. R.C. 1972. Prairie history, management, and restoration in southern Illinois. Pages 15-21 in S. Zimmerman, ed. Proceedings of the Second Midwest Prairie Conference. Madison, WI. Anderson, R.C. 1982. An evolutionary model sum- marizing the roles of fire, climate, and grazing animals in the origin and maintenance of grasslands: an end paper. Pages 297-308 in J. Estes and J. Brunken. eds. Grasses and grasslands: systematics and ecology. University of Oklahoma Press. Nonnan. Anderson R.C. 1990. The historic role of fire in the North American grassland. Pages 8-18 in S. Collin and L. Wallace, eds. Fire in North American tallgrass prairies. University of Oklahoma Press. Norman. Anderson. R.C. 1991. The presettlement forests of Illinois. In J. Ebinger. ed. Proceedings of an Oak Woodland Workshop (in press). Axelrod. D. 1985. Rise of the grassland biome. central North America. Botanical Review 51: 164-196. Britton. W.A.. and A.S. Messenger. 1970. Com- puted soil moisture patterns in and around the prairie peninsula during the great drought of 1933-1934. Transactions of the Illinois State Academy of Science 62(2):181-187. Curtis. J.T. 1959. The vegetation of Wisconsin. University of Wisconsin Press. Madison. 657 p. Ebinger. J.E. 1981. Vegetation of glacial drift hill prairies in east-central Illinois. Castanea 46: 115-121. Eisenbero. E. 1989. Back to Eden. The Atlantic Monthly. Noveniher. pp. 57-89. E\iRs, R.A. 1955. Hill prairies of Illinois. Illinois Natural History Survey Bulletin 26:368-446. Fehrenbacher. J.. B. Ra'i. and J. Alexander. 1968. Illinois soils and factors in their development. Pages 165-175 in RE. Bergslrom. ed. The Quater- nary of Illinois. Special Publication 14. College of Agriculture. University of Illinois. Urbana. Gerhard. F. 1857. Illinois as it is. Keen and Lee. Chicago; Charles Desilver. Philadelphia. 451 p. Gleason. H.A. 1907. .N botanical survey of the Illinois River valley and region. Pan 2. Pages 149-11)4 ,„ c.A. Hart and HA. Gleason. eds. On the biologv of sand areas of Illinois. Illinois State Laboratory of Natural Histois Bulletin 7. April IWl Symposium Proceedings: Our Living Heritage 391 Gi EASON. H.A. 1913. The relation of forest distribu- tion and prairie fires in the middlewest. Torreya 13: 173-lSl. Gleasos. H.A. 1922. Vegetational histon,' of the middlewest. Annals of the American Association of Geographers 12:39-86. GoLLEV. P.M.. AM) F.B. GoLEEY. EDS. 1972. Papers from a symposium on tropical ecology with an emphasis on organic production. Institute of Ecology. University of Georgia, Athens. 418 p. Grimm. E. 1984. Fire and other factors controlling the Big Woods Vegetation of Minnesota in the mid- nineteenth century. Ecological Monographs .'i4: 291-311. IvERSON. L.R. 198S. Land-use changes in Illinois. USA: the influence of land.scape attributes on current and historic land use. Landscape Ecology 2:45-61. KiLBiRN. RD.. AM) D.K. Warren. 1963. Vegetation-soil relationships in hill prairies. Transactions of the Illinois State Academy of Science 56(3); 142-145. King. J. 1981. Late Quaternary vegetational history of Illinois. Ecological Monographs 5 1 :43-62. KoMAREK. E.V. 1968. Lightning and lightning fires as ecological forces. Pages 169-197 //; Proceedings of the Annual Tall Timber Fire Ecology Conference No. 8. Tall Timbers Research Station. Tallahassee, FL. McClain, W.E. 1983. Photodocumentation of the loss of Hill Prairie within Pere Marquette State Park, Jersey County, Illinois. Transactions of the Illinois State Academy of Science 76(3 & 4):343-346. McNaughton, S.J. 1979. Grazing as an optimum process: grass-ungulate relationships in the Serengeti. Ecological Monographs 55:259-294. McNalghtos, S.J. 1984. Grazing lawns: animals in herds, plant form, and coevolution. American Naturalist 124:863-886. Owen. D., and R. Wiegert. 1981. Mutualism between grasses and grazers: an evolutionary hypothesis. Oikos .36:376-378. Parrish, J., AND F. Bazzaz. 1982. Organization of grassland communities. Pages 233-254 in J. Estes, R. Tyrl, and J. Brunken, eds. Grasses and grasslands: systcmatics and ecology. University of Oklahoma Press, Norman. > Prince, E., and J. Burnham. 1908. History of McLean County.Vol. 1. Munsell Publishing Com- pany, Chicago. IL. 744 p. Pyne, S.J. 1986. Fire and prairie ecosystems. Pages 131-137 in G. Clambcy and R. Pemble, eds. The prairie: past, present and future. Proceedings of the Ninth North American Prairie Conference. Tri- college University Center for Environmental Studies, North Dakota State University, Fargo. Rice, E., and R. Parenti. 1978. Causes of decrease of productivity in undisturbed tallgrass prairie. American Journal of Botany 65:1091-1097. Risser. p., O. Birney, H. Blocker, W. Parton, and J. Weins. 1981. The true prairie ecosystem. Hutchinson Ross Publishing Co., Stroudsburg, PA. 557 p. Rodgers,C., AND R.C.Anderson. 1979. Presettle- ment vegetation of two prairie peninsula counties. Botanical Gazette 140:232-240. Schwegman, J. 1973. Comprehensive plan for the Illinois Nature Preserves System. Part 2. The Natural Divisions of Illinois. Illinois Nature Preserves Commission, Rockford, IL. 32 p -I- map. Stebbins, G. 1981. Coevolution of grasses and herbivores. Annals of the Missouri Botanical Garden 68:75-86. Stewart, O.C. 1951. Burning and natural vegeta- tion in the United States. Geographical Review 41 : 317-320. Stewart, O.C. 1956. Fire as the first great force employed by man. Pages 1 15-133 in W. Thomas, ed. Man's role in changing the face of the earth. University of Chicago Press, Chicago. Tainton, N., AND M. Mentis. 1984. Fire in grasslands. Pages 1 17-147 /;; P. de V. Booysen and N. Tainton. eds. Ecological effects of fire in South Africa ecosystems. Springer-Verlag, Boston, MA. Transeau. E. 1935. The prairie peninsula. Ecology 16:423-427. Vestal, A.G. 1913. An associational study of Illinois sand prairie. Illinois State Laboratory of Natural History Bulletin 10:1-94. Weaver, J. 1954. North American prairie. Johnson Publishing Co.. Lincoln, NB. .348 p. Wells, P. 1970. Postglacial vegetational history of the great plains. Science 167:1574-1582. White, J. 1978. Illinois natural areas inventory technical report. Vol. I: Survey methods and results. Illinois Natural Areas Inventory, Urbana. 426 p. Willman, H., and J. Frye. 1970. The Pleistocene stratigraphy of Illinois. Illinois State Geological Survey Bulletin 94. 204 p. Wright, H. 1974. Range burning. Journal of Range Management 27:5-1 1. Prairie and Savanna-restricted Insects of the Chicago Region Ron Panzer, Northeastern Illinois University Abstract. Numerous remnants of the presettle- ment prairies and savannas of the Chicago region have survived. Unfortunately, most are very small and degraded. Nearly all are isolated within vast expanses of human-dominated landscape. For the past nine years, 1 have surveyed grasshopper, katydid, froghopper, leafhopper, treehopper, butterfly, and macro moth (in part) communities on a variety of these remnants in an attempt to gauge the status and site size requirements of the remnant- restricted members of these groups. Few of the species considered in this study (probably less than 5% ) have been extirpated. Most, perhaps as many as 80-90%, have adapted to our degraded modern land- scape and can be found in a variety of human- dominated settings. Among the 10 to 20% that are restricted to native grassland remnants, roughly half are seemingly secure, surviving on at least a dozen protected sites. Approximately one-fifth of the remnant-restricted species are known from fewer than six sites and may be endangered within this area. Most of the remnant-restricted insects considered in this study have survived on relatively small sites. One-third have been found on sites smaller than ."i hectares. Two- thirds have been found on sites of less than 40 hectares. More than four-fifths have been recorded on two or more sites of less than 300 hectares. (Even sites as small as 1 hectare can support a few restricted species.) Site size is clearly an important detenninant of butterfly diversity on smaller remnants ( 1-60 ha) in this region. .192 Prairie Birds of Illinois: Population Response to Two Centuries of Habitat Change James R. Herkert, Department of Ecology, Ethology, and Evolution, University of Illinois at Urbana-Champaign The landscape of Illinois has changed consid- erably over the last two hundred years. The once extensive, unbroken stretches of prairie have given way to agricultural crops, and this shift has had a substantial impact on the state's bird fauna. The purpose of this paper is twofold: to examine how the prairie bird fauna of Illinois has responded to changes in the state's landscape and to discuss how a highly fragmented landscape may be affecting prairie bird populations. POPULATION STUDIES 1800-1900 Prior to European settlement, prairie occupied approximately 8.5 million hectares in Illinois, nearly two-thirds of the state (Anderson 1970). The area of prairie was over 1.5 times that of forests, which at approximately 5.5 million hectares was the next most abundant habitat type (Graber and Graber 1963). The composi- tion of the presettlement bird fauna in Illinois is not well known. Current data, however, show that prairies support relatively low densities of breeding birds. Bird densities in tallgrass prairie habitat average roughly 1.8 pairs per hectare (Cody 1985). Comparable densities for eastem deciduous forests are 8.7 pairs per hectare (obtained from 87 breeding bird studies published in American Birds, volumes 37 and 38). Because of the low density of birds in prairie habitat. Graber and Graber ( 1963) estimated that only 35-40% of the presettle- ment bird fauna of Illinois was composed of prairie birds; forest birds, however, may have accounted for as much as 55-60%. Unfortunately, by the time much of the early ornithological work was conducted within Illinois ( 1 850- 1 900), considerable losses of prairie habitat had already occurred. By 1850 prairie habitat had been reduced to 2.1 million hectares (Graber and Graber 1963), a reduction of almost 75% or roughly }i.y/( per year since 1810. We can, therefore, reasonably assume that some changes in the prairie bird fauna had occurred prior to any detailed study. Neverthe- less, the works of Ridgway (1873, 1889, 1895) for central and southern Illinois and Nelson ( 1876) for northern Illinois can be used to estimate prairie bird abundances in the state prior to 1900 (Table 1). A number of prairie bird species initially benefited from the conversion of prairie to farmland. Those that benefited most include the homed lark, vesper sparrow, and greater prairie-chicken. The increase in homed larks and vesper sparrows was largely due to their ability to colonize and breed in cultivated habitats, which by 1900 had become the most abundant habitat type in the state (Graber and Graber 1963). The initial opening of the prairies and forests to agriculture produced an intermixed pattern of food and cover that was beneficial to many species of upland game, including the greater prairie-chicken (Weste- meier and Edwards 1987). This shift in habitat coupled perhaps with a reduction in the abundance of predatory animals (due to fur trapping and hunting) allowed the prairie- chicken to reach a peak abundance within Illinois of approxiinately 10 million birds by I860 (Westemeier 1986; Westemeier and Edwards 1987). Prairie-chickens started to decline soon after reaching their peak abun- dance. Nelson (1876) listed them as once excessively abundant but now rather scarce in the Chicago region and as less numerous in all the more settled areas of the state due to egg collection by humans, unrestricted hunting, and loss of habitat. POPULATION STUDIES 1900-1950 During 1906-1909. a systematic survey of the state's birds was conducted by Alfred Gross and Howard Ray of the Illinois .Stale Labora- tory of Natural History (I-orbes 1913; Forbes and Gross 1922). These surveys provided the 393 394 linois Natural Hisiorv Survey Bulletin Vol. 34 An. 4 first quantitative estimates of breeding bird populations within Illinois. A summary of the relative abundances of the most common grassland species encountered by Gross and Ray in ungrazed grass, mixed-hay. and pasture from the north and central regions of Illinois are shown in Table I . Gross and Ray found bobolinks and meadowlarks (eastern and western) to be the most common bird species, accounting for more than 50% of all birds en- countered in these habitats. Of the birds listed as abundant or very common by Ridgway (1889. 1895) and Nelson (1876). the greater prairie-chicken, upland sandpiper, and Henslow's sparrow apparently experienced the greatest declines between the mid- 1 800s and the censuses of Gross and Ray. All three of these species were uncommon or rare by 1906 (Table 1 ). In the first paper addressing changes in the bird fauna of Illinois, Ridgway (1915) discussed changes that had taken place in the half century preceding 1915. He cites three prairie birds—the greater prairie-chicken. upland sandpiper, and dickcissel—as exjjeri- encing serious declines during this period. The greater prairie-chicken and upland sandpiper were considered on the verge of elimination within Illinois because of shooting and destruc- tion of nests by dogs and cats. The dickcissel had also dramatically declined during this period for "unknown reasons" (Ridgway I9I5). Ridgway first noted the dickcissel's decrease around 1885 and stated that by 1915 this species never reached more than one-fourth and usually less than one-tenth its former numbers. Coincidentally. Fretwell (1986) documented a sevenfold increase in grazing pressure between 1870 and 1884 on the dickcissel's primary w intering grounds in Venezuela, a factor that he believed could significantly affect w inter resources and. in turn, dickcissel numbers. POPULATION STUDIES 1950-1989 In I956-I958. the census routes of Gross and Ray were repeated by Graber and Graber (1963) of the Illinois Natural History Surrey Table 1. April IWI Symposium Proceedings: Our Living Heritage 395 (Table 1 ). The Grabers believed that the red- winged blackbird, homed lark, and dickcissel had shown large statewide population increases between 1909'and 1956. Red-winged blackbird numbers had almost doubled since the earlier censuses of Gross and Ray due to the ability of this species to invade nearly all terrestrial habitats within the state (Graber and Graber 1963). Ridgway (1889) noted that although very common, the nests of red-winged blackbirds were always in or in very close proximity to a swamp or marsh. Gross and Ray, however, found red- winged blackbirds in all the grassland habitats they^censused in 1906-1909. although 60'7f of the state's population of these birds still nested in marshes (Graber and Graber 1963). From 1909 to 1956, red-winged blackbird densities within grassland habitats in Illinois increased nearly tenfold. The species had become far more common in grasslands than in marshes, with individuals inhabiting marshes accounting for less than 3% of the state's population (Graber and Graber 1963). The statewide increase in homed larks between 1909 and 1956 corresponded to their shift from primarily grassland to cultivated habitats, especially row-cropped fields. This switch from a rapidly declining to a rapidly increasing habitat greatly benefited the homed lark, which Graber and Graber (1963) recog- nized as the species that had increased most dramatically between 1909 and 1956. The Grabers attributed the dickcissel's statewide increase to an expansion in acreage of agricul- turally disturbed grasslands, a type of habitat that this species may prefer over true prairie (Kendeigh 1941: Graber and Graber 1963: Zimmerman 1971 ). Most species of prairie birds, however, had shown either little or no statewide population change between 1909 and 1956 (Graber and Graber 1963). The bobolink, song sparrow, and savannah sparrow showed slight increases, the upland sandpiper and field sparrow slight decreases, and the vesper sparrow, grasshopper sparrow, and American goldfinch no change. Between 1987 and 1990. 1 conducted research on the breeding birds of Illinois grasslands; however, my field methods differed from those used by Gross and Ray and the Grabers and direct comparisons are therefore not possible (see Herkert 1991 and Graber and Graber 1963 for descriptions of methods). Nevertheless, a comparison of relative abun- dances of these species indicates that the current composition of grassland bird fauna is probably very similar to that of the late 1950s (Table 1 ). Red-winged blackbirds remain the most common species, outnumbering the next most abundant species, the eastem meadow- lark, by more than two to one. In fact, four of the five most abundant species are the same in my censuses and in those of Graber and Graber (Table I ). An estimate of how prairie bird numbers have changed since the Grabers' census can be obtained from data collected by the United States Fish and Wildlife Service's cooperative breeding bird survey (unpublished data). These data from Illinois for 1967-1989 show that nearly all prairie bird species have experienced population declines during this 23-year interval (Table 1 ). Some of the fomierly most abundant prairie bird species, for example, the bobolink, have shown declines as high as 90% during this period. The causes of these recent population declines are not well understood but probably are a consequence of continued loss of grass- land habitat within Illinois. Although the initial loss of prairie habitat within Illinois was rapid and extensive, the reduction of prairie habitat has continued in recent decades. By 1978, less than 1,000 hectares of high-quality prairie remained in the state (Schwegman 1983). The loss of prairie habitat was originally offset by the creation of secondary grasslands such as hayfields and pastures, habitats which the majority of prairie birds found suitable for breeding (Graber and Graber 1963). In fact, none of the characteristic birds of the eastern tallgrass prairie region are considered endemic to prairie habitat (Risser et al. 1981). Acreage of these secondary grassland habitats, however, has also recently declined. For example, the amount of hay within Illinois was reduced by more than half, from 850.000 to 400.000 hectares, between 1960 and 1989 (Illinois Agricultural Statistics Service 1988, 1989). The amount of pasture within Illinois has also been greatly reduced, with pasture occupying only 607.000 hectares in 1987 (U.S. Department of Commerce Bureau of the Census 1989) compared with 2.5 million hectares in 1906. The continued loss of both native and agricultural grassland habitats in Illinois has contributed to an increasingly fragmented landscape. 396 Illinois Natural History Survey Bulletin Vol. 34 An. 4 HABITAT FRAGMENTATION The process of habitat fragmentation sets off a series of events that can ultimately have a major effect on breeding bird communities. Changes associated with increased fragmenta- tion include a decrease in the total amount of habitat, a decrease in the average size of habitat patches, increased patch isolation, and an increase in the ratio of edge to interior habitat, all of which may have important consequences for breeding birds (Wiens 1989). The most important consequence of habitat fragmentation is the loss of large amounts of habitat and the resulting losses of individuals, local populations, and possibly even species. Surprisingly, only three species of prairie birds have been extirpated from Illinois despite the extensive loss of prairie habitat (Table 2). Bowles et al. (1980) origi- nally listed four species as extirpated from Illinois, but the sandhill crane has returned to the state as a breeding species (Kleen 1988). The remaining three species (sharp-tailed grouse, swallow-tailed kite, and whooping crane) were extirpated prior to or very shortly after 1900 (Bowles et al. 1980). Another 13 prairie bird species are now considered to be threatened or endangered within Illinois (Table 2), primarily as a direct result of extensive habitat loss, A number of these endangered and threatened species may be on the verge of extirpation within Illinois. The greater prairie- chicken, for example, once one of our most abundant prairie birds, now has a statewide population of less than 100 individuals (R. Westemeier, pers. comm.). The reduction of the average patch size that accompanies habitat fragmentation also has serious consequences for breeding birds. Small patches may be too small to meet the minimum territory requirements for a species or may lack essential resources necessary for the establish- ment of populations (Diamond 1975). The responses of individual species to reductions in patch size are variable, but nearly all bird species exhibit a minimum area threshold below which they never occur (e.g.. Lynch and Whigham 1984; Haydcn et al. 198.5; Robbins et al. 1989). Six prairie bird species were never encountered during my research within Illinois on areas of less than 10 hectares (Table 3), despite the fact that the average territory for four of these species (bobolink, savannah sparrow, grasshopper sparrow, and Henslow's sparrow) is typically less than 2.5 hectares (Wiens 1969). Many prairie bird species avoid small areas, and small grasslands have been shown to support impoverished breeding bird faunas (Samson 1980: Howe et al. 1985; Herkert 1991 ). The number of breeding bird species in grassland fragments is strongly related to fragment size, with large fragments supporting significantly more species than small fragments (Samson 1980: Herkert 1991). In addition, small habitat patches generally support small numbers of individuals, thus greatly increasing the influence of stochastic events on population demography. As a result, small isolated bird populations have been shown to exhibit relatively high turnover rates (e.g.. Diamond 1969; Diamond and May 1977; Morse 1977) and therefore a higher probability of local population extinction. In Illinois, the natural areas inventory ( 1975-1978) identified only 253 remnants, totaling 950 hectares, of high-quality prairie Table 2. Extirpated, endangered, and threatened birds of Illinois prairies (from Bowles et al. 1980). Endangered American bittern Yellow rail Black rail Bachman's sparrow Greater prairie-chicken Swainson's hawk Short-eared owl Northern harrier Upland sandpiper Sandhill crane Threatened Loggerhead shrike Henslow's sparrow Brewer's blackbird Extirpated Sharp-tailed grouse Whooping crane Swallow-tailed kite Table 3. Minimum areas of encounter tor 17 grass- land bird species from 24 grassland fragments located in northeaslem and east-central Illinois (1987-1989). Grasslands ranged from 5 to 650 hectares. <10 hectares Field sparrow .American goldfinch Song sparrow Dickcissel Ring-necked pheasant Sedge wren Cotiimon > ellow throat Rcd-w Migcd blackbird Northern bohwhile Eastern meadow lark Vesper sparrow lO-.^O hectares Bobolink Sa\annah sparrow Grasshopper spaaow Henslow "s sparrow >30 hectares Upland sandpiper Northern harrier April 1991 Symposium Proceedings: Our Living Heritage 397 within the state (Schwegman 1983). The majority of these remnants were small, most less than 20 hectares, and would therefore be expected to support very few. if any. prairie bird species. Grasslands of 100 hectares or more may be necessary to support just five prairie interior species (Herkert 1991 ). Increases in patch isolation can also increase the probability of local population extinctions due to decreased immigration rates. Island biogeography theory predicts that immigration rates will be affected by both patch isolation and size, with the lowest immigration rates occurring on patches that are small and well isolated from a colonizing source (MacArthur and Wilson 1967), Whether mainland fragments act as true islands with respect to immigration, however, is open to question because mainland fragments are not surrounded by totally inhospitable habitat as are true islands and therefore might not show immigration rates that are strongly dependent on patch isolation. A number of studies conducted in the eastern deciduous forests of North America have demonstrated that isola- tion does have a significant effect on species richness within forest fragments (Robbins 1980: Howe 1984; Lynch and Whigham 1984; Askins et al. 1987). Researchers working in forests on other continents, however, have found no evidence supporting isolation as a significant factor affecting species richness within fragments (Kitchener et al. 1982; Howe 1984; Opdam et al. 1985). The effects of isolation on immigration rates in midwestem grasslands have not been studied to date. Harris (1984) points out that island biogeography theory assumes that islands always have a mainland source pool for immigration; for terrestrial fragments, however, the "mainland" source may be lost as a result of the fragmentation process. In this case, the recolonization of mainland fragments must occur between habitat patches. The integrity of the whole system would then depend on the existence of areas large enough to produce enough surplus individuals to provide dispers- ers as well as maintain stable populations within a particular preserve. Another consequence of habitat fragmen- tation is an increase in the ratio of edge to interior habitat as patch si/e decreases (Butcher et al. 1981; Temple 1986). This increase may result in the loss of species that require interior habitats and an increase in the abundance of edge species (Whilcomb et al. 1981; Ambuel and Temple 198.^; Temple 1986). Small grasslands are usually dominated by such nonprairie species as red-winged blackbirds and common yellowthroats and support few prairie interior bird species (Herkert 1991 ). Moreover, the increase in the ratio of edge to interior habitat may lead to lower reproductive success for nesting grassland birds. Levels of both nest predation and parasitism have been shown to be higher in edge habitats than in grassland interiors, especially if the edge is a field-woodland or field-shrubland border (Best 1978; Gates and Gysel 1978; Johnson and Temple 1986, 1990; Burger 1988). Finally, we must remember that loss of prairie and grassland habitat in Illinois, and throughout the Midwest, affects birds primarily during the breeding .season. The majority of prairie bird species are migratory and spend only a fraction of any given year on the breeding grounds. Similar alterations of wintering and possibly migratory habitat may also significantly affect these bird species. The degree to which events off of the breeding grounds affect prairie birds are not well known. For such species as the dickcissel, however, events on the wintering grounds and migratory routes may be the most important factors affecting distribution and abundance patterns on the breeding grounds in the Midwest (Fretwell 1986). The fact that processes operating outside the boundaries of Illinois affect bird populations within the state does not excuse us from being concerned about events occurring within Illinois, but rather should alert us to the year-round needs of these species. If conservation efforts to preserve prairie birds are to succeed, management efforts must address not only processes operating on the breeding grounds within Illinois but the migratory and wintering needs of these species as well. ACKNOWLEDGMENTS This research was funded in part by the S. Charles Kendeigh Memorial Fund. Illinois Nongame Wildlife Fund, Sigma Xi, and the University of Illinois at Urbana-Champaign. G.C. Sanderson, S.K. Robinson, R.E. Warner, and two anonymous reviewers provided helpful comments and editorial assistance on previous drafts of the manuscript. 398 linols Nalural History Survey Bulletin Vol. 34 An. 4 LITERATURE CITED Anderson, R.C. 1970. Prairies in the prairie state. Transactions of the Illinois State Academy of Science 63(2):2 14-221. Ambuel. B., and S.A. Temple. 1983. Area- dependent changes in the bird communities and vegetation structure of southern Wisconsin forests. Ecology 64:1057-1068. AsKiNS, R.A.. M.J. Philbrick. and D.S. Sigeno. 1987. Relationship between the regional abundance of forest and the composition of forest bird commu- nities. Biological Conservation 39:129-152. Best. L.B. 1978. Field sparrow reproductive success and nesting ecology. Auk 95:9-22. Bowles, M.L., K. Kerr. R.H. Thom, and D.E. Birkenholz. 1980. Threatened, endangered, and extirpated birds of Illinois prairies. Illinois Audubon Bulletin 193:2-11. Burger, L.D. 1988. Relations between forest and prairie fragmentation and depredation of artificial nests in Missouri. M.A. thesis. University of Missouri, Columbia. 62 p. Butcher. G.S., W.A. Niering. W.J. Barry, and R.H. Goodwin. 1981. Equilibrium biogeography and the size of nature preserves: an avian case study. Oecologia 49:29-37. Cody, M.L. 1985. Habitat selection in grassland and open-country birds. Pages 191-226 in M.L. Cody, ed. Habitat selection in birds. Academic Press, Orlando., FL. Diamond, J.M. 1969. Avifaunal equilibrium and species turnover rates on the Channel Islands of California. Proceedings of the National Academy of Sciences 64:57-63. Diamond, J.M. 1975. Assembly of species commu- nities. Pages 342-444 in M.L. Cody and J.M. Diamond, eds. Ecology and evolution of communi- ties. Harvard University Press, Cambridge, MA. Diamond, J.M., and R.M. May. 1977. Species turnover rates on islands: dependence on census interval. Science 197:266-270. Forbes, S.A. 1913. The midsummer bird life of Illinois: a statistical study. Illinois Laboratory of Natural History Bulletin 9:373-385. Forbes, S.A., and A.O. Gross. 1922. The numbers and local distribution in summer of Illinois land birds of the open country. Illinois Natural History Survey Bulletin 14:187-218. Fretwell. S. 1986. Distribution and abundance of the dickcissel. Current Ornithology 4:21 1-242. Gates, J.E., and L.W. Gysel. 1978. Avian nest dispersion and fledging success in field-forest ecotones. Ecology 59:871-883. Graber, R.R., and J.W. Graber. 1963. A compara- tive study of bird populations in Illinois. 1906-1909 and 1956-1958. Illinois Natural History Survey Bulletin 28:383-528. Harris. L.D. 1984. The fragmented forest: island biogeography theory and the preservation of biotic diversity. University of Chicago Press, Chicago. 211 p. Hayden, T.J.. J. Faaborg. and R.L. Clawson. 1985. Estimates of minimum area requirements of Missouri forest birds. Transactions of the Missouri Academy of Sciences 19:11-22. Herkert. J.R. 1991. An ecological study of the breeding birds of grassland habitats within Illinois. Ph.D. thesis. University of Illinois at Urbana- Champaign. 105 p. Howe. R.W. 1984. Local dynamics of bird assem- blages in small forest habitat islands in Australia and North America. Ecology 56:1585-1601. Howe, R.W., D.M. Roosa, J. P. Schalfenblel. and W.R. SiLCOCK. 1985. Distribution and abundance of birds in the loess hills of western low a. Proceedings of the Iowa Academy of Sciences 92:164-175. Illinois Agricultural Statistics Service. 1988. Illinois agricultural statistics: annual summary. 1988. Bulletin 88-1. U.S. Department of Agriculture, Illinois Agricultural Statistics Service. Springfield. 123 p. Illinois Agricultural Statistics Service. 1989. Illinois farm report. Vol. 10, No. 17. Illinois Depart- ment of Agriculture. Springfield. [4 p.| Johnson. R.G.. and S.A. Temple. 1986. .Assessing habitat quality for birds nesting in fragmented tallgrass prairies. Pages 245-250 in J. A. Vemer. M.L. Mortison. and C.J. Ralph, eds. Wildlife 2000. University of Wisconsin Press, Madison. Johnson, R.G.. and S.A. Temple. 1990. Nest predation and brood parasitism of tallgrass prairie birds. Journal of Wildlife Management 54:106-1 II. Kendeich. S.C. 1941. Birds of a prairie community. The Condor 43: 1 65-1 74. Kitchener. D.J.. J. Dell, and B.C. Mi ir. 1982. Birds in western Australia wheatbelt reserves: implications for conservation. Biological Conserva- tion 22:127-163. April IWl SympoNium Proceedings: Our Lning Heritage 399 Kleen, V.M. I98S. Field notes: the breeding season. Illinois birds and birding. 4:1 1-lS. LvNCH, J.F., AND D.F. Whicham. 1984. Effects of forest fragmentation on breeding bird communities in Maryland. LISA. Biological Conservation 28:287-324. MacArthlr. R.H.. AND E.O. Wii son. 1967. The theory of island biogeography. Princeton University Press, Princeton, NJ. 203 p. Morse. D.H. 1977. The occupation of small islands by passerine birds. The Condor 79:399-412. Nelson, E.W. 1876. Birds of northeastern Illinois, Bulletin of the Essex Institute 8:89-155. Opdam, p., G. Rusdijk, and F. Hustings. 1985. Bird communities in small woods in an agricultural landscape: effects of area and isolation. Biological Conservation 34:333-352. RiDGWAY. R. 1873. The prairie birds of southern Illinois. American Naturalist 7:197-203. RiDGWAY. R. 1889. The ornithology of Illinois. Vol. 1. Illinois State Laboratory of Natural History. 520 p. RiDGWAY. R. 1895. The ornithology of Illinois. Vol. II. Illinois State Laboratory of Natural History. 202 p. RiDGWAY. R. 1915. Bird-life in southern Illinois. IV. Changes which have taken place in half a century. Bird-Lore 17:191-198. RissER, P.G.. E.C. BiRNEY, H.D. Blocker, S.W. May. W.J. Parton. and J.A. Wiens. I98I. The true prairie ecosystem. US/IBP Synthesis Series. Vol. 16. Hutchinson Ross, Stroudsburg, PA. 557 p. RoBBiNS, C.S. 1980. Effect of forest fragmentation on breeding bird populations in the Piedmont of the mid-Atlantic region. Atlantic Naturalist 33:31-36. RoBBiNS, C.S., D.K. Dawson, and B.A. Dowell. 1989. Habitat area requirements of breeding forest birds of the middle Atlantic states. Wildlife Monographs 103. 34 p. Sam.son, F.B. 1980. Island biogeography and the conservation of prairie birds. Proceedings of the North American Prairie Conference 7:293-305. ScHWEGMAN, J. 1983. Illinois prairie: then and now. Illinois Audubori Bulletin 205:2-14. Temple, S.A. 1986. Predicting impacts of habitat fragmentation on forest birds: a comparison of two models. Pages 301-304 //; J. Vcrner. M.L. Morrison, and C.J. Ralph, eds. Modeling habitat relationships of terrestrial vertebrates. University of Wisconsin Press, Madison. U.S. Department of Commerce Bureai of the Census. 1989 1987 Census of Agriculture. Vol. 1, Geographic Area Series; Part 13. Illinois state and county data. 478 p. Westemeier, R.L. 1986. Problems in prairie grass management on prairie-chicken sanctuaries in Illinois. Page 1 in R.D. Applegate, ed. Proceedings of the First Central Illinois Prairie Conference. Westemeier. R.L.. and W.R. Edwards. 1987. Prairie-chickens: survival in the Midwest. Pages 1 19-131 ill H. Kallman. ed. Restoring America's wildlife 1937-1987: the first .50 years of the Federal Aid in Wildlife Restoration (Piltman-Robertson) Act. U.S. Department of the Interior. Fish and Wildlife Service. U.S. Government Printing Office, Washington, DC. Whitcomb, R.F., C.S. Robbins. J.F. Lynch, B.L. Whitcomb, M.K. Klimkiewilz, and D. Bystrak. 1981 . Effects of forest fragmentation on avifauna of the eastern deciduous forests. Pages 125-205 //( R.L. Burgess and D.M. Sharpe, eds. Forest island dynamics in man-dominated landscapes. Springer- Verlag. New York. Wiens. J.A. 1969. An approach to the study of ecological relationships among grassland birds. Ornithological Monographs 8:1-93. Wiens, J.A. 1989. The ecology of bird communities. Vol. 2. Cambridge University Press, Cambridge and New York. 316 p. Zimmerman, J.L. 1971. The territory and its density- dependent effect in Spi:a americaiui. Auk 88; 591-612. Session Three: Wetlands Wluil would the world he. once hereft Ofwel and wildness? Let them he left. O let them he left, wildness and wet: Long live the weeds and the wilderness yet. —Gerard Manley Hopkins While most Illinois residents may not consider their state to be particularly wet. early settlers had a very different impression. Writing in 1 833, the year Chicago was incorporated as a village. Colbee Benton observed that Chicago "stands on the highest part of the prairie, and in the wet part of the season the water is so deep that it is necessary to wade from the town for some miles to gain the dry prairie. Notwith- standing the water standing on the prairie and the low. marshy places, and the dead-looking river, it is considered a healthy place." The retreat of the glaciers left numerous large and small streams w ith many associated wet areas. Much of northeastern Illinois had abundant diverse wetlands, and central Illinois was a montage of wet prairies and marshes. Extensive tracts of tupelo-cypress swamps could be found in the far southern part of the state. Wetlands are diverse and complex places. The most common wetlands in Illinois are marshes and sedge meadows, although ponds, fens, seeps, wet prairies, swamps, and bogs are also present. Marshes form where water is above the soil surface for all or nearly all of the year—along the margins of ponds, lakes, or rivers, in places sheltered from strong currents and waves. Sedge meadows are usually associ- ated with fens. Here the water level is near or just below the surface most of the year, and this habitat often merges into marshes as the water depth increases. The surface of the vegetation hides countless tussocks or humps fonned b\ the tussock sedge, and these vary in height from a few inches to over a foot. The terms hog and /('// are often used inconsistently. e\'en inter- changeably, and considerable confusion has been the result. In general, bogs are acidic and poor in minerals, with most of the water coming from rainfall and surface runoff and most of the new peat dcscloping from sphagnum moss. Fens range from acidic hi alkaline and arc rich in minerals; much o\' the w ater comes from groundwater that has percolated through calcareous bedrock or gravel. Peat is produced primarily by sedges and grasses. Seeps are characterized by groundw ater that has reached the surface in a diffuse rather than a concen- trated flow. Seeps form w hen groundwater that has percolated down through porous sand or gravel reaches a layer of impermeable material and flows outward, usually at the base of a bluff or ravine. Swamps are areas where the soil is saturated or covered w ith surface water for most of the growing season: woody vegetation dominates. What was formerly looked upon as sources of disease and pestilence, "sacred to the ague and fever." are currently \ iewed in a new light. The importance of wetlands is only now being realized: they store runoff after major rains and slow ly release it: the\ filter silt and pollutants from water; and the\ are tre- mendously productive, providing habitat for a diversity of plants and animals. Illinois originally had an estimated 8 million acres of wetlands. Since Illinois became a state in 1 S 1 8. more than 95'"( of these have been drained w ith a concomitant loss in the natural processes that wetlands provide. High-quality wetlands that reflect preseltlement conditions are exceedingly rare today; only about 6.000 acres remain. The papers presented at this session re- viewed the state of our wetlands, documenting what has been lost as well as what must be restored or preserved. Particular attention was given to the plants and animals that depend on the unique habitats of wetlands. 400 Aquatic and Wetland Plants of Illinois John E. Schwegman, Natural Heritage Division, Illinois Department of Conservation Abstract. Over 100 of the 172 families of vascular plants growing without cultivation in Illinois have species adapted to aquatic or moist soil habitats. These wetland plants range from ferns and their allies to conifers to flowering plants. Growth forms include herbs, shrubs, and trees, any of which may function as the domi- nant species of a plant community or as minor components. Some important wetland plant families in Illinois are the sedge family (Cyperaceae), grass family (Poaceae). pond- weed family (Potamogetonaceae), duckweed family (Lemnaceae), smartweed family (Polygonaceae). and sunflower family (Aster- aceae). In providing for their own growth and reproduction, these plants make up the vegeta- tion component of wetlands and provide much of the food, nesting cover, and escape cover for wetland animals. Common aquatic and emergent species of wetland communities in Illinois include coontail (Ceratophylliini demersiim) beneath the surface of calm waters, duckweeds {Lemna sp.) floating on the surface, bulrushes {Scirpus sp.) and cattail (Typhu latifolla) in marshes, buttonbush (Cephalantluts occideiitalis) in shrub swamps, and bald cypress (Taxodium distichiim) and water tupelo (Nyssa aquatica) in wooded swamps. A wider variety of species occupy moist soil communities as opposed to aquatic communities. 401 Breeding Biology and Larval Life History of Four Species of Ambystoma (Amphibia: Caudata) in East-central Illinois Michael A. Morris, Cuivre Island Field Station, Western Illinois University Abstract. Temporary aquatic habitats, whether roadside ditches, tlooded fields, or woodland ponds are essential in maintaining the biodiver- sity of Illinois. Nineteen species of Illinois amphibians (50% of the state's species) depend on such habitats for breeding. Two species of reptiles breed in those habitats, and 8 to 10 more use them as foraging areas. In addition, these temporary aquatic habitats are important for many invertebrate species. Kickapoo State Park, located in Vermil- ion County. Illinois, provides just such tempo- rary aquatic habitats, and this paper records my observations of the breeding biology and larval history of four species of salamanders, genus Amhystoma (Amphibia: Caudata) in that setting from' 1973-1984. Amhystoma opacum migrated to the dry beds of two vernal hilltop ponds at Kickapoo State Park in late September or October. The females oviposited under the mat of leaf litter that covered the pond beds and abandoned the eggs in late fall. Amhystoma platinciim. A. te.xamim. A. maculatum. and A. platincum X A. texamim hybrids migrated to the ponds under stimulus of rains in February and March, provided groundwater was sufficient to fill the ponds to a depth of at least 25 cm. Amhystoma maculatum migrated 3-7 days later than the other spring-breeding species. In years when no standing water was present in the ponds, spring migration was prolonged or involved few animals. Amhystonui tcxamim and A. maculatum males deposited beds of spermato- phores in different locations on the pond bottoms. The gynogenetic A. platincum used sperm from the A. tcxaiium spermatophores to initiate cleavage of their eggs, and fertilization occasionally occurred. Amhystoma platincum and A. tcxanum laid eggs in water less than 30 centimeters deep; A. nuiciilatum laid eggs in water at least as deep as 30 centimeters. Amhystoma opacum larvae hatched within 24 hours after the ponds filled in the spring. Eggs of the other species hatched in 3-6 weeks. Larvae grew little for 2 weeks and then grew rapidly for about 1 .5 months. Little further growth occurred before transformation. Larvae usually transformed in late May (A. opacum) or late June (the other species). Amhystoma opacum larvae were always able to transform, but in most years the ponds dried before most, if not all, of the larvae of the other species could transform. Larvae are opportunis- tic feeders, and their food included volvocids. ostracods. branchiopods, annelids, insects, and in the case of A. opacum. the larvae of other salamanders. 402 Ecological Integrity of Two Southern Illinois Wetlands M. Ann Phillippi, Department of Zoology. Southern Illinois University at Carbondaie Palustrine and riverine wetlands in Illinois are increasinely rare ec'i)s\ stems. L'nti)rtunaiely. the declining wetland habital in Illinois is not an isolated phenomenon (Mitsch and Gosselink 1986: Illinois Department of Conservation 1988). Wetlands across this country are in jeopardy due to drainage lor a variety of human endeavors, primarily agriculture, or to the a.ssociated and chronic but less dramatic threat, soil erosion. The presettiemeni area of wetlands in this country is diftlcult to ascertain, and estimates vary from 51 to 87 million hectares (Greeson et al. 1979). The rapidity with which our wetlands disappeared is diltlcult to comprehend. B> the early 1950s. 35. Shrub swamp community of Lovets Pond in mid-June I9S6. The almost impenetrable growth of buttonbush {Cephulaiilhii.s (mUlcnhilis) in the background is surrounded primarily by lizard's tail (SawwKs ccinuus). Photo by author. Figure 4. True swamp community of Lovets Pond in mid-June 1986. New growth of arrow arum {Pehandra virf^inica). foreground, covers the lowest points in this community. A variety of tree species are seen in the background, including pumpkin ash {Fraxhms projumlii). water locust (GlcJilsia aqiialica). and red maple {Acer nihnim). Photo by author. Figure .5. Marsh community of Lovets Pond in mid- May I9S6. .Such graminoid plants as bur reed {Spariniimim I'Kiyiaipiini). giant bulrush iScirpii.s hihcniacnunilanii). and common cattail [Typlui hilijiiliii) surround the marsh edge. Duckweeds (SpinHlc/a spp. and Lcmnu spp.). water meal (Wolffia sp.), and sponge plant {Liiiinohiiim spoiiaici) cover [he surface by summer. Photo by author. 406 llinois Natural Hislory Survey Bulletin Vol. 34 Art. 4 six-week intervals, January through June 1986. Samples were preserved and later sorted and identified to the lowest practical taxon. Cache River and Wetlands. During the summer of 1986 a team of biologists (Phillippi et al. 1986) surveyed the aquatic fauna at 23 sites within the Cache River drainage (Figure 6). Two dipnet samples were taken from a representative portion of each of the sites and the organisms sorted and identified to the lowest practical taxon. Figure 6. Large bald cypress (TiimhUuih clisiicluini) along the Cache River and its wetlands provide a major attraction tor canoeists. Pholo by Marti Crothers. RESULTS AND DISCUSSION Lovets Pond. The true swamp and marsh com- munities of Lovets Pond contained the highest number of macroinvertebrate taxa: the lowest number was found in the open pond (Table 1 ). Samples taken from the true s\v amp and shrub swamp communities yielded the largest number of individuals: once again, the open pond yielded the lowest number (Table 1 ). The number of taxa and individuals in each community fluctuated in a roughly similar fashion across the seasons: however, no pattern within or across the four communities in regard to the diversity (H") of macroin\ ertebrates was discernible (Figure 7). No single plant commu- nity always harbored the highest or lowest species diversity. Even so. the four plant communities contained distinct macroinverte- brate assemblages, at least qualitatively, and this distinction was demonstrated using Jaccard"s similarity coefficients and group average clustering (Figure 8). Cluster I is predominated by the shrub swamp macro- invertebrate cominunity. cluster 2 by the true swamp, and cluster 4 by the open pond community. The macroinvertebrate community inhabiting the marsh is indistinct from those of the other three communities e\ en though the marsh is the most isolated of the four commu- nities. These data suggest that this small wetland harbors distinct and diverse macro- invertebrate communities— communities that are known to be dramatically affected by human-caused changes in substrate and \\ ater quality (Greeson et al. 1979). From the practical viewpoint of conservation biologv. the ecological integrity of Lovets Pond can be considered good and thus \\ orth\ of protection. Cache River and Wetlands. .Approxi- mately 2.30 aquatic and semiaquatic macro- invertebrate taxa were collected from the 23 sites. The number of taxa and individuals at Table 1. Total number of taxa and individuals for the tour major planl communities of Lo\ et> Pond. Ranges are given in parentheses. April 1491 SympoMtim Proceedings: Our Liviiii; Heritage 407 each site ranged from 21-66 and 212-2.735. respectively. Only 7% (17 taxa) were found at i or more sites. Of those 1 7 taxa, 6 were crustaceans (aquatic sowbugs, sideswimmers. shrimps, and crayfishes) and 6 were surface or water-column dwelling beetles (Coleoptera) or bugs (Heteroptera). 0\er 20.500 individuals were examined, excluding those taken from qualitative samples. The clubtail dragonfly {Ariof^ompliiis iiiaxuclli) was observed and/or collected at 4 of 23 sites. This species was known from only a few Gulf Coast states until June of 1985 when a single adult male was collected at Mermet Lake in Massac County. Illinois. Thus, the Cache population may be the only viable one in the state. Sampling also yielded such rare to uncommon bugs as the water scorpion (Nepa apicukita) and such common but hard to collect bugs as the marsh treader or water measurer (Hyclromeira martini). In the sites most disturbed with a heavy silt load, at least a few surface-dwelling insects (for example. Gcrris mart^iiuiiiis and TrepohaU's spp.) were found. Gcrris »uir,i;i- natiis is perhaps the most common strider in the Cache system. To assess the ecological integrity of the various Cache sites, species diversity measure- ments (H") were calculated and can be com- pared with those found at Lovets Pond. Four sites have a relatively high species diversity (0.898-1 . 131): the Cache River at Highway 37. Snake Hole. Eagle Pond, and Long Reach. The Cache River at Highway 37 is a highly dis- turbed site. The north bank has been cleared and a levee built. The channel has been dredged and carries a very heavy silt load. Long Reach is also a heavily silted portion of the main channel. Snake Hole is a well-shaded pond located at the base of a rocky-boulder cliff in an area known as Little Black Slough. This state- owned site is generally the least silted of any of the Cache wetlands. Eagle Pond, also heavily silted, is a popular canoeing destination because of its picturesque cypress knees and buttonbush thickets. Sites with moderate macroinvertebrate species diversity (0.651-0.834) are heavily silted, including Wildcat BluffAValson Pond and Short Reach, both owned by the Illinois Department of Conservation. The other 5 sites with moderate diversity are privately owned. The remaining 12 sites have low species diversities Pond I Shrub swamp I I True swamp Marsh Mar Apr Sampling dale Figure 7. Shannon diversity (H') values (N = 2) for the macroinvertebrate communities inhabiting the four major plant communities of Lovets Pond. open pond{ shrub swamp { marsh - true swamp" shrub swamp 1 c,- c, c,- c,- c true swamp marsh ^ shrub swamp- marsh - open pond true swamp- marsh - 1 408 Illinois Natural History Survey Bulletin Vol. 34 An. 4 (0.170-0.612), including Limekiln Spring and Slough which is owned by The Nature Conser- vancy and is generally considered "protected." That site exemplifies the major threat to all the remaining Cache wetlands—excessive habitat destruction due to siltation from agricultural endeavors. Even the integrity of the areas "protected" by the state, by The Conservancy, or by other private groups is being threatened by siltation, which is obliterating most of the available aquatic habitat. The quality of the adjacent terrestrial habitat is variable: some sites are cleared of all vegetation and others have mature, high-quality forests or swamps. Sites with the most disturbed terrestrial component generally have the least diverse aquatic component. Even though the data reveal that macroinvertebrate species diversity is generally low. enough islands of diversity seem to exist to reclaim the area if it were protected from further siltation and other degrading influences. The ecological integrity of the Cache and its wetlands cannot, however, be considered good, especially in light of the excessively silted substrate of the areas 1 visited. LITERATURE CITED CowARUis, L.M.. V. Cakter. F.C. Golet. avd E.T. LaRoe. 1979, Classification of wetlands and deepwater habitats of the United States. U.S. Fish and Wildlife Service, Washington, iXT. 103 p. Greeson. P.E.. J.R. Clark, and J.E. Clark, eds. 1979. Wetland functions and values: the state of our understanding. Proceedings of the .National Sympo- sium on Wetlands. American Water Resources Association, Minneapolis, MN. 674 p. Illinois Department of Conservation. 1988. A field guide to the wetlands of Illinois. Illinois Department of Conservation. Springfield. 244 p. MiTSCH, W.J., AND J.G. GossELiNK. 1986. Wetlands. Van Nostrand Reinhold Co., Inc., New York. 539 p. Phillippi. M.A., B.M. Birr, and R.A. Brandon. 1986. A preliminary survey of the aquatic fauna of the Cache River in Johnson and Pulaski counties. Illinois. Illinois Department of Consenation, Springfield. 414 p. Phillippi, M.A., and M. Peterson. 1986. A pre- liminary investigation of the aquatic macro- invertebrate community of Lovels Pond in Jackson County. Illinois. Illinois Department of Conserva- tion. Springfield. 33 p. CONCLUSIONS I have examined the ecological integrity of two southern Illinois wetlands: one small, Lovets Pond, and a much larger one, the Cache. I have concluded that if drastic measures are not immediately initiated (such as the proposed Cypress Creek National Wildlife Refuge), the future of the Cache River system is bleak, primarily due to excessive siltation. On the other hand, Lovets Pond appears adequately protected from siltation by a forest buffer. We should act now to preserve both systems and all other Illinois wetlands, regard- less of size. Large, disturbed systems such as the Cache may recover, thereby preserving a large portion of the biodiversity of Illinois. Small systems such as Lovets Pond also serve to preserve their share of biodiversity. ACKNOWLEDGMENTS Portions of this research were funded by the Department of Zoology, College of Science. Southern Illinois University at Carbondale, and by the Illinois Nongamc Wildlife Conservation Fund. Melvin L. Warren, Jr., graciously reviewed an early draft of the manuscript. Status and Distribution of Wetland Mammals in Illinois Joyce E. Hofmann. Illinois Natural History Survey Wetlands are highly productive and diverse habitats that supply important resources for many mammalian species (Fritzell 1988). The objectives of this paper are to list the mainmals that are found in the wetlands of Illinois, to identify species that are threatened or endan- gered, and to discuss the distribution of wetland mammals within the state, especially those restricted to wetland habitats. Only palustrine wetlands, rather than riverine or lacustrine systems, are considered. The.se shallow water habitats are categorized as palustrine emergent (sedge meadow, marsh, bog. and fen), palus- trine scrub-shrub, and palustrine forested (swamp and seasonally or temporarily flooded forested wetland) wetlands (Cowardin et al. 1979). Illinois mammals that inhabit these types of wetlands are listed in Table 1. Most of the mammals in Table 1 are terrestrial or semiaquatic. Bats are not typically considered wetland mammals, although any Illinois species might well forage above marshes or bogs or along the edges of swamps. Research conducted by the Illinois Natural History Survey and the Illinois Department of Conservation revealed that forested wetlands in southern Illinois provide roosting sites for three species of bats. In May 1988. a radio-tagged pregnant Indiana bat was found roosting behind loo.se bark on a dead American elm (Ulnius ameriianu) in a wetland created by subsidence in Saline County. A lactating southeastern bat was radio-tracked to the hollow base of a living tupelo gum (Nyssa aquatica) in Little Black Slough in Johnson County during the summer of 1989; she shared this roost with at least 100 other individuals. Four Rafinesque's big-eared bats were also found roosting in a tupelo gum in the slough during that summer. To stress the importance of palustrine forested wetlands to these three endangered species. I have listed them in Table 1 . Other species of bats also roost in trees during the summer, although little is known about their specific habitat prefer- ences (Barbour and Davis 1969; Hoffmeisler 1989). Species likely to roost in forested wetlands include the silver-haired bat (Lasionyctcris noctivuiians), northern long- eared bat (Myotis scptentrionalis). and evening bat (Nycticeiiis hiimcralis). Table 1 includes one federally endan- gered species, the Indiana bat (Endangered Species Act, 16th U.S. Congress, docket \5}>\): three state endangered species, the southeastern bat, Rafinesque's big-eared bat, and river otter; and three state threatened species, the marsh rice rat, golden mouse, and bobcat (Illinois Administrative Code, Title 17, Chapter I, subchapter c, part 1010.30, as amended March 17, 1989). These seven species and the swamp rabbit (Kjolhaug et al. 1987) are uncommon in Illinois; all other species in Table 1 range from relatively common to abundant (Hoffmeister 1989). The beaver and white-tailed deer are now common even though both species had been nearly extirpated from the state by the end of the 19th century (Pietsch 1954; Pietsch 1956; Hoffmeister 1989). Some of the species in Table 1 have restricted ranges within Illinois. The southern short-tailed shrew, big-eared bat, southeastern bat, swamp rabbit, marsh rice rat, and golden mouse occur only in the southern portion of the state (Ellis et al. 1978; Feldhamer and Paine 1987; Kjolhaug et al. 1987; Hoffmeisler 1989; Illinois Natural Heritage Database). The main breeding population of river otters is along the Mississippi River north of Rock Island (Jo Daviess. Carroll. Whiteside, and Rock Island counties); a smaller population may occur in the Heron Pond-Little Black Slough area of the Cache River drainage (Johnson County) in southern Illinois (Anderson 1982). Most bobcats probably occur in the northwestern and southernmost portions of Illinois where relatively large expanses of suitable habitat remain (Illinois Natural Heritage Database). The Virginia opossum, southern flying squirrel. 409 410 llinois Natural Hisiory Survey Bulletin Vol. 34 An. 4 beaver, white-footed mouse, woodland vole, muskrat, house mouse, meadow jumping mouse, gray fox, raccoon, mink, and white- tailed deer, on the other hand, occur throughout the state (Hoffmeister 1989). The remaining species in Table 1 have ranges that cover much of Illinois. The meadow vole and least weasel occur in the northern half of the state, and the northern short-tailed shrew is found primarily in the northern two-thirds (Hoffmeister 1989). The southeastern shrew and southern bog lemming occur in the southem two-thirds of Illinois, although bog lemmings have been caught in Carroll County (Hoffmeister 1989). The Indiana bat. though rare, has been found in 20 counties in central and southem Illinois during the summer (Illinois Natural Heritage Database). The masked shrew may have a discontinuous distribution in Illinois, occurring primarily in the northern third of the state but also in at least two southem counties (Hoff- meister 1989). Many species of mammals are habitat generalists. The home ranges of larger mam- mals, such as the bobcat and \shite-tailed deer, typically consist of a mosaic of forested areas interspersed with open areas that could include wetlands (Schwartz and Schuartz 1981 ). Many smaller mammals may be found in a variety of habitats. The masked shrew, for example, is Table 1. Wetland mammals of activities (e.g., foraging, nestin; are included if thev are known Illinois. Terrestrial and semiaquatic species are included if their 5) are conducted entirely or partly within palustrine wetlands; bats to roost in wetlands. Common name Scientific name Habitat Virginia opossum Masked shrew Southeastern shrew Northern short-tailed shrew Southern short-tailed shrew Indiana bat Southeastern bat Rafinesque's big-eared bat Swamp rabbit Southern flying squirrel Beaver Marsh rice rat White-footed mouse Golden mouse Meadow vole Woodland vole Muskrat Southern bog lemming House mouse Meadow jumping mouse Gray fox Raccoon Least weasel Mink River otter Bobcat White-tailed deer Diddphh virghiiaua Sorex cinereus Sorex longirostris BInriiui brcvicnnda Blnn)in cnroliiwnsis Mx/otis sodnlis Myoiis nuftroripnrius PIccotus mfiih'squii Si/lvilngiis nqunticiis Glauavm/s volnns Castor cnundeusis On/zomys palustris Pcroinysciis leucopus Odirokvmfs uuttnlli Micivtus pcnitsylranicus Micivtus pinctorum Ondatra zibethicus Syuaptomi/s coopcri Miis niusculus Zapus hudsojiius Urocyon cincreonrgeiiteus Procx/ou lotor Miistcia nivalin Muftiia rifon Ultra caiiadcmis Fclif rufus Odocoileus virgiiiiauiif B FVV FW B BV M S.M M 5VV M SM M SW BV SW SW SS SV\' BV BV M SW BV M SS SW M SM SS BV SS SW BV M SM M BV M SW M M BV M SM BV M SS SW BV M M BV SW BV SS SW BV M SS SW BV ' Palustrine wetland habitats used bv these species are coded as follows: M = marsh SM = sedge meadow B = bog SS = scruh-shrub wetland SW = swamp FW = seasonally or temporarily Hooded forested wetland Sources on habitat use: Barlxnir and Davis 1974; Schwartz and Schwartz I'^SI : Mumlord and Whitaker 1982; lones and Birnoy N8S; and Hottmeister 1989. April 1991 Symposium Proceedings: Our Living Heriiage 411 abundant in sedge meadows and marshes in northern Illinois but also inhabits sand prairies. flatwoods. fencerows, pastures, and succes- sional fields (Mumford and Whitaker 1982; Mahan and Heidorn 1984; Szafoni 1989). The white-footed mouse has been trapped in sedge meadows and marshes (Mahan and Heidorn 1984; Szafoni 1989) but is more typically an inhabitant of upland forests and shrublands. In fact, few species of mammals are specifically adapted for living in wetland environments (Fritzell 1988). Most of the species listed in Table I are not restricted to wetlands and. therefore, their distribution and abundance are not indicative of or significantly limited by the status of wetlands in Illinois. The swamp rabbit and marsh rice rat are the Illinois mammals that are most limited to palustrine wetlands. The beaver, muskrat. and river otter are also closely associated with wetlands but are more aquatic in their habits and could be considered species of rivers, streams, lakes, or ponds. The swamp rabbit and rice rat are uncommon and have limited distributions within the state: the remainder of this paper will discuss their distribution and status in more detail. The swamp rabbit is a representative of the Eastern-Austral faunal element, the group of mammalian species whose distributions are centered in the southeastern United States (Jones and Bimey 1988). Its northern limit is in Illinois and Indiana and coincides with that of the southern swamp forest community at approximately the 24"C temperature isoline (Chapman and Feldhamer 1981 ). Swamp rabbits rarely occur far from water and inhabit floodplain forests, cypress swamps, and canebrakes (Cory 1912; Layne 1958; Barbour and Davis 1974; Sealander 1979; Chapman and Feldhamer 1981; Hoffmeister 1989). In Indiana, swamp rabbits were found in areas where low ridges were interspersed with small wooded sloughs and grassy marshes (Terrel 1972). In the early 1900s. the swamp rabbit was known to occur in swamps along the Missis- sippi and Ohio rivers in Illinois; its northern limits were thought to be a few miles south of Grand Tower in Jackson County and 5 miles below Golconda in Pope County (Howell 1910). The earliest specimens were collected in Alexander and Johnson counties (Cory 1912) and Williamson Countv (Necker and Hatfield 1941 ). Cockrum ( 1949) believed that the swamp rabbit had extended its range during the early twentieth century as far north as Jefferson County. He reported that hunters had killed swamp rabbits in Franklin County during 1935-19.^6 and in Jefferson County during 19.^6. More recently, specimens and possible sightings have been recorded in several other counties: Marion. Massac. Perry. Randolph, and Union (Layne 1958); Bond. Calhoun. Gallatin. Lawrence. Wabash. Washington, and Wayne (Klimstra and Roseberry 1969); and Edwards and White (Terrel 1969). These findings indicate a range extending northward to Calhoun. Bond, and Lawrence counties (Figure 1 ). Whether these new records repre- sent a range expansion or improved reporting is. however, uncertain. Kjolhaug et al. ( 1987) of the Cooperative Wildlife Research Laboratory conducted intensive searches for swamp rabbits or their sign (pellets on logs, vegetation clippings, tracks) in 1 1 southern Illinois counties and limited searches in three others during 1984-1985. Sign was recorded at 22 sites along the Bay Creek and Big Muddy. Cache, Mississippi, and Ohio River drainages in Alexander. Franklin. Jackson. Johnson. Massac. Pope. Pulaski, and Union counties (Figure I ). No sign was found in Gallatin. Lawrence, Saline, Wabash. Wayne, and Williamson counties, although all but Saline had earlier records. Other counties for which previous records exist were not searched during the study by Kjolhaug et al. (1987). Kjolhaug etal. 1987 D Earlier records Figure 1. .Southern Illinois counlics in which swamp rabbit sign was found by Kjolhaug cl al. ( 19S7) and earlier records for ihis species (Houcll I '>!(); Cory 1^12; Ncckcrand Hatfield I Wl; Cockrum l'M9: Layne I'J.'SS; Klimstra and Roseberry 1969; Terrel 1969). 412 linois Nalural History Survey Bulletin Vol. 34 An. 4 The results of the study by Kjolhaug and his colleagues suggest that Alexander. Johnson, Massac. Pulaski, and Union counties support several secure populations of swamp rabbits, whereas this species is present at low densities and with limited distributions in Franklin. Jackson, and Pope counties. Only 12,585 ha in southern Illinois were found to support swamp rabbits, although approximately 2,000 addi- tional hectares of suitable habitat were identi- fied. The state of Illinois was the most impor- tant owner of swamp rabbit habitat. The potential habitat for this species in Illinois and neighboring states has been drastically reduced by the construction of levees and drainage ditches and the conversion of bottomlands to agricultural use (Terrel 1972: Barbour and Davis 1974: Korte and Fredrickson 1977; Whitaker and Arbell 1986: Kjolhaug et al. 1987; Hoffmeister 1989). In Indiana, for example, swamp rabbits are now restricted to a single county (Whitaker and Arbell 1986). Fragmentation of bottomland forest and swamp has created islands surrounded by unsuitable habitat, a condition limiting successful disper- sal and reestablishment of extirpated local populations. Kjolhaug et al. ( 1987) concluded that swamp rabbits were unlikely to colonize vacant areas of habitat and that existing populations will continue to be extirpated. The marsh rice rat (Figure 2) is the only member of this predominantly Neotropical genus with an extensive range in the United States (Honacki et al. 1982). The southern portion of Illinois is at the northern limit of its range, although rice rats once occurred as far north in the state as Peoria County, where their remains have been found at an archeological site (Baker 1936). Rice rats are common throughout much of their range, where they inhabit coastal and freshwater marshes and swamps and areas along lakes, rivers, and streams (Wolfe 1982). The first modem specimens from Illinois were collected at Olive Branch and Cache in Alexander County (Cory 1912: Necker and Hatfield 1941 ). McLaughlin and Robertson (1951 ) collected two specimens in Johnson County and concluded that rice rats were limited to swampy areas v\ ithin the Coastal Plain Division of the state (Schwegman 1973). More recently, rice rats have also been reported from Franklin, Jackson. Massac. Pulaski. Union, and Williamson counties (Klimstra and Scott 1956: Klimstra 1969; Klimstra and Roseberry 1969; Rose and Seegert 1982; Urbanek and Klimstra 1986: Illinois Natural Heritage Database). In addition, the remains of a rice rat were found in the stomach of a mink collected from an unspecified location in Washington County (Casson 1984). The recent range of the rice rat. inferred from these limited records, extends through the Ozark. Mississippi River Bottomlands, and Shaunee Hills divi- sions into the Mt. Vernon Hill Country Section of the Southern Till Plain Division. During 1986-1987 staff members of the Illinois Natural History Suney live-trapped in 17 southern Illinois counties to assess the current distribution of the rice rat (Figure 3; Hofmann et al. 1991 ). A total trapping effon of 3.5 1 7 trap-nights resulted in 1 . 1 1 1 captures of small mammals representing 13 species. Rice rats were captured at 13 sites in 10 counties (Figure 3). They were found for the First time in Hamilton. Pope. Saline, and White counties and were also trapped at new localities in Alexan- der. Franklin. Jackson. Johnson. Massac, and Williamson counties. Rice rats were not caught in Pulaski. Union, and Washington counties, although earlier records existed. Despite recent trapping efforts, no rice rats have been captured in Gallatin. Hardin. Perry . and Randolph counties. These results suggest that rice rats occur farther to the northeast in the state than indicated by pre\ ious records (into the Wabash Border Division). Rice rats may have expanded their range within the state, perhaps using waterways and wet areas along highway and railroad rights-of-way as dispersal corridors; more likely, they were present in Hamilton. Figure 2. A rice ral live-trapped in Franklin County dunny llie disiribulion stuilv of l''S{>-l')S7. Photo by Manlvii MotTis. April IWl Syiiiposmiii Proceedings: Our Living Heritage 413 Pope, Saline, and White counties but un- reported due to limited sampling. Although some potentially suitable habitat for rice rats occurs in Perry, Randolph, and Washington counties, their primary range appears to extend only as far north as Franklin and Jackson counties in southwestern Illinois. In addition to the 10 counties in which rice rats were captured during the Survey's study, they may also occur in Pulaski and Union counties. Existing records, however, do not suggest that they would be common in either county. The only specimen known from Pulaski County was found dead in a field in January 1987 (Illinois Natural Heritage Database), and no rice rats have been reported from Union County since 1958 (Klimstra and Roseberry 1969; Illinois Natural Heritage Database). During the Survey's study, 132 rice rats were captured, a number that includes at least 99 individuals. Nearly half (45-49 individuals) were trapped at the Saline County site and more than 70% (72-76 individuals) were caught at just four sites in Alexander, Jackson, Pope, and Saline counties. At the nine remain- ing sites, the number of individuals trapped was Figure 3. Trapping sites in southem Illinois, 1986-1987 are shown as circles; sites at which captures of rice rats occurred contain dots ( Hofrnann et al. 1990). The range of this species based on earlier records is indicated in gray (Cory l'>12; Necker and Hallield l')4l; McLaughlin and Robertson [')5\: Klinislra and .Scott IV.^fi: Klimstra 1969; Klimstra and Roseberry 1969; Rose and Secgert 1982; Casson 1984; Urbanek and Klimstra 1986; Illinois Natural Heritage Database). 5 or fewer. Despite the fact that their range within the state is more extensive than had been thought, rice rats do not appear to be common in Illinois and their continued status as a threatened species appears to be warranted. Areas where rice rats were captured were characterized by standing water and a dense cover of emergent herbaceous vegetation, specifically sedges {Carcx spp.), rushes Uuncus spp.), bulrushes (Scirpus spp.), spike rushes {Ek'ocluiris spp.), or cattails (Typha spp.). Trapping was most successful in roadside ditches along county or state highways and along the shores of ponds and lakes. Since many extensive wetlands in southern Illinois no longer exist, rice rats occupy islands of original or manmade wetland habitat that are often small and widely scattered. Such areas cannot support large populations, and small popula- tions are especially vulnerable to extirpation due to environmental changes, disease, or predation. As with the swamp rabbit, recoloni- zation of a site could be hainpered by the large expanses of unsuitable habitat separating it from other populations. The remaining wetland habitat of the swamp rabbit and marsh rice rat needs to be protected. Such protection should be the highest priority, but habitat enhancement and recreation may also warrant consideration. State and federally owned forested bottomlands could be managed to increase their quality as swamp rabbit habitat (Kjolhaug et al. 1987). Modern surface-mining reclamation techniques have the potential to create habitat suitable for rice rats (Ohisson et al. 1982: Klimstra and Nawrot 1985). There is no guarantee, however, that such areas would be colonized because existing populations are widely dispersed. Relocation of animals to newly created or existing wetlands may be a useful management procedure. Whitaker and Arbell ( 1986) recom- mended reintroduction of swamp rabbits into areas with suitable habitat in Indiana, and the feasibility of relocating rice rats is cuiTcntly being studied by the Illinois Natural History Survey in southern Illinois. Finally, the fact that most other mammals that use wetlands are tlexible in their habitat choices does not mean that there is reason for complacency about the loss of remaining Illinois wetlands. 414 Illinois Natural Histor> Sur\ey Bulletin Vol. 34 An. 4 ACKNOWLEDGMENTS The study on rice rat distribution was supported by the Ilhnois Endangered Species Protection Board and the Illinois Department of Transpor- tation. The following individuals assisted with that study: Doug Carney. Monica Cox, Barbara Frase, Jean Karnes, Dennis Keene, Patti Malmborg, Ray Smith, Mary Kay Solecki, John Taft, Karen Tyrell, Eric Ulaszek, and Mark Wetzel. Bat data were collected by James E. Gardner, Illinois Natural History Survey; James D. Garner, Illinois Department of Conserva- tion: and the author with assistance from Randall Collins, Rebecca Porter, and Kelley Neelley, and with support from the Illinois De- partment of Transportation. Donald F. Hoff- meister and John O. Whitaker, Jr., provided valuable reviews of the manuscript. LITERATURE CITED Anderson, E.A. 1982. Status and distribution of the river otter {Ultra canadensis) in Illinois. Unpub- lished paper. Southern Illinois University, Carbon- dale. 79 p. Baker, F.C. 1936. Remains of animal life from the Kingston Kitchen tnidden site near Peoria, Illinois. Transactions of the Illinois State Acadetny of Science 29:243-246. Barbour, R.W.. and W.H. Davis. 1969. Bats of America. University Press of Kentucky, Lexington. 286 p. Barbour, R.W., and W.H. Davis. 1974. Mammals of Kentucky. University Press of Kentucky, Lexington. 322 p. Casson, J.E. 1984. A new distribution suggested for the rice rat {Oryzoniys palKslris) in southern Illinois. Transactions of the Illinois Stale Academy of Science 77(3 &4):28.S. Chapman, J.A., and G.A. Ffldhamer. 1981. Sylvilai^us aqnaliciis. Mammalian Species 151:1-4. CocKRi'M, EL. 1949. Range-extension of the swamp rabbit in Illinois. Journal of Mammalogy 30:427-429. 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Kjolhaug, M.S., A. WooLF. and W.D. Klimstra. 1987. Current status and distribution of the swamp rabbit in Illinois. Transactions of the Illinois State Academy of Science 80(3 & 4):299-307. Klimstra. W.D. 1969. Mammals of the Pine Hills-Wolf Lake-LaRue Swamp complex. Chicago Academy of Sciences Natural History Miscellanea I88:l-I(). Ki imstra. W.D.. \ND JR. Nawrot. 1985. Wetlands as a bvproduct of surface mining: Midwest perspec- tive. Pages 107-1 19 ,„ R.P. Bio'oks. D.E. Samuel, and J.B. Hill. eds. Proceedmgs of Wetlands and Water Managemeiu on Mmed Lands Conference. Penns\l\anKi State l'ni\ersit\. Lni\ersit\ Park. April IWl SynipoMuni Proceedings: Our Living Heritage 415 Klimstra, W.D.. AND J.L. RosEBKRR'i. 1969. Addi- tional observalions on some southern Illinois mamtiials. Transactions of the Illinois State Academy of Science 62(4):4I3-417. Klimstra. W.D., and T.G. Scott. 1936. Distribu- tion of the rice rat in southern Illinois. Chicago Academy of Sciences Natural History Miscellanea 154:1-3. KoKTF. P. A.. AND L.H. Fredrickson. 1977. Swamp rabbit distribution in Missouri. Transactions of the Missouri Academy of Science 10 and 1 1 -.12-11. La-inf. J.N. 1958. Notes on mammals of southern Illinois. American Midland Naturalist 60:219-254. Mah.an. C.J.. AND R.R. Hkidorn. 1984. The mammals of Iroquois County Conservation Area. Transactions of the Illinois State Academy of Science 77( 1 & 2):23-28. McLalghlin, C.A.. and W.B. Robertson. 1951. A new record of the rice rat. Oiyzomys palustris pahislris. from southern Illinois. Chicago Academy of Sciences Natural History Miscellanea 80:1-2. MtMFORD, R.E.. and J.O. Whitaker. Jr. 1982. Mammals of Indiana. Indiana University Press, Bloomington. 537 p. Necker, W.L.. and D.M. Hatfield. 1941. Mam- mals of Illinois. Bulletin of the Chicago Academy of Sciences 6:17-60. Ohlsson. K.E.. A.E. Robb. Jr.. C.E. Glindon. Jr.. D.E. Savhjel. and R.L. Smith. 1982. Best current practices for fish and wildlife on surface-mined land in the northern Appalachian coal region. FWS/OBS- 81/45. Eastern Energy and Land Use Team. U.S. Fish and Wildlife Service. Keameysville. WV. 305 p. Pietsch, L.R. 1954. White-tailed deer populations in Illinois. Illinois Natural Histor>' Survey Biological Notes .34. 22 p. Pietsch. L.R. 1956. The beaver in Illinois. Transac- tions of the Illinois State Academy of Science 49:193-201. Rose, R.K., and G.L. Seegert. 1982. Small mammals of the Ohio River floodplain in western Kentucky and adjacent Illinois. Transactions of the Kentucky Academy of Science 43:150-155. Sealander, J. a. 1979. A guide to Arkansas mammals. River Road Press. Conway. AR. 313 p. Schwartz, C.W., and E.R. Schwartz. 1981. The wild mammals of Missouri. 3rd cd. University of Missouri Press and Missouri Department of Conservation. Columbia. 356 p. S( Mwi gman. J.E. 1973. Comprehensive plan for the Illinois Nature Preserves System. Part 2: The natural divisions of Illinois. Illinois Nature Preserves Commission. Rockford. 32 p. S/AFOM. R.E. 1989. The small mammals of Rockton Nature Preserve. Winnebago County. Illinois. Trans- actions of the Illinois State Academy of Science 82 (3&4):177-18l. Ti:rrfl. T.L. 1969. The swamp rabbit [Sylvilaiius cH/iuilicii.s) In Indiana. M.S. thesis. Purdue Univer- sity. West Lafayette. IN. 126 p. Tirrfl. T.L. 1972. The swamp rabbit i.S\l\ilai;iis Miiutliciis) In Indiana. American Midland Naturalist 87:28.3-295. Urbanek. R.P.. AND W.D. Klimstra. 1986. Verte- brates and vegetation on a surface-mined area in southern Illinois. Transactions of the Illinois State Academy of Science 79(3 & 4): 1 75-1 87. Whitaker. J.O.. Jr.. and B. Arbell. 1986. The swamp rabbit. SylviUivii.s aqiuiliciis. in Indiana. Proceedings of the Indiana Academy of Science 95:563-570. Wolfe. J.L. 1982. Oiyzomys palusiris. Mammalian Species 176:1-5. Session Four: Streams and Caves wild liciii.s ihc fislics when llicy i ry'.'—Henry David Thoreau More than half of the 13,200 miles of streams in Illinois have been dredged, channelized, dammed, or altered in other ways. Our rivers and streams suffer from pollution, siltation. and the introduction of exotic organisms. The Illinois River, described by Thomas Jefferson as "a fine river, clear, gentle, and without rapids," has served as Chicago's sewer, a waterway for untold numbers of barges made navigable only by numerous dams, and a repository for much of the eroded topsoil from central Illinois farm- land. The "typical" stream in east-central Illinois is a narrow ditch lined with mowed grass, weeds, or row crops, stretching across the landscape and disappearing into the distance. The Cache River in southern Illinois was diverted in 1916 via the Post Creek Cutoff Designed to alleviate flooding, it cut the river in two. allowing a portion to drain directly into the Ohio River. As a result, the Lower Cache has become a sluggish trickle that even flows backwards upon occasion. Suiprisingly, a few high-quality streams remain in Illinois. The Biological Stream Characterization, an index of stream quality completed in 1989, identified 24 stream seg- ments of excellent quality throughout the state. These total somewhat less than 300 miles, about 4% of the stream mileage in Illinois. Included in this group are segments of the Kishwaukee in northern Illinois, the Vermilion in east-central Illinois, and Lusk and Big creeks in the Shawnee National Forest. Caves in Illinois have fared somewhat better. Four areas where caves are typically found correspond to major outcroppings of calcareous rocks. More than 4S0 caves were identified during the I9S8 inventory conducted by the Illinois State Museum. The remarkabls' stable, insulated environ- ments of caves support a unique biota. For the most part, these organisms are adapted to little or no light and limited food resources. Caves are regarded as natural zoological laboratories where, because of the relative simplicity of the ecosystem, important biological and evolution- ary questions can be studied. One presentation at this session surveyed the nature of Illinois streams—what we have, what we have lost, and \\ hat can yet be done by way of restoration and preservation. Two speakers focused on inhabitants of that stream system, the surprisingly di\ erse and dynamic Illinois fish fauna and the varied mussel populations. The fourth paper described the cave environment and ecosystem, noting the often overlooked values of this unique natural resource. 416 The Fishes of IlHnois: An Overview of a Dynamic Fauna Brooks M. Burr, Department of Zoology, Southern Illinois University at Carbondale Just over ten years ago. Smith ( 1979) published the most recent comprehensive summary of the Illinois fish fauna. His review revealed 199 fish species. 1 86 of which were considered native to the state. A major finding was that the Illinois fish fauna is dynamic and that the distributions of many species have changed considerably since the first comprehensive survey of Illinois fishes by Forbes and Richardson ([1908]. 1920). Becau.se of introductions of alien species, dis- coveries of species new to Illinois, and redis- coveries of species formerly thought to be extirpated, the composition of the Illinois fish fauna is in need of clarification. In the past decade, the greater redhorse. Miixnsronia nilciuieunesi (Seegert 1986). and the cypress minnow, Hyhogiiatliiis liarl {Bun and Mayden 1982: Warren and Burr 1989). which were thought to have been extirpated from Illinois, were rediscovered. Examination of collections made prior to Smith's survey and recent collecting have documented previouslv unreponed records for the bluehead shiner. Plcniiiolropis luihhsi (Burr and Warren 1986). and the pallid shiner. Hyhopsls ainiiis (Warren and Burr 1988). Three fishes were recently added to the state fauna: in addition, new localities for ten other uncommon species were reported by Burret al. ( 19X8) and by Dimmick ( 1988). The introduced rainbow smelt. Osmcius inorclax. has recently and rapidly extended its range in Illinois (Burr and Mayden 1980). The w hite perch. Mnronc amcricanu. previously un- recorded from Illinois, has dispersed into the Illinois portion of Lake Michigan (Savitz et al. 1989a). The bighead carp. Hypophthalmiclilhys nohilis. silver carp. //ypi>pliiliah)ilchiliy.\ inoliiri.x. and rudtl. Scardiniii.s eryilirophihal- miis— three Eurasian exotics unknown in Illinois streams during Smith's ( 1979) survey — are being captured at a number of localities, particularly big rivers and reservoirs. My purpose here is to review briefly the Illinois fish launa and record some of the changes that have occurred in the composition of Illinois fishes since Smith's (1979) compre- hensive .study. I have used the term 'alien' to encompass any fish species "of foreign origin" that is either an exotic, a transplant, or a recenll\ invading species from more southern latitudes. HISTORICAL PERSPECTIVE The history of ichthyological investigations in Illinois is a rich one. At the time the Illinois Natural History Society was established in 1858. approximately three-fourths of the Illinois fish fauna had been named and described by such distinguished ichthyologists as Samuel L. Mitchill ( 1 764-1 83 1 ), Charles A. Lesueur (1778-1846), Constantine S. Rafinesque ( 1783-1840), Jared R Kirtland (1793-1877), Louis Agassiz (1807-1873). and Charles F. Girard (1822-1895). Fourteen of the species described were first discovered in Illinois. The first regional list of Illinois fishes was prepared by Robert Kennicott (1855). who treated the fishes of the Chicago area. Compre- hensive catalogs of fishes of the entire state later appeared by Edward W. Nelson ( 1 876). David Starr Jordan ( 1878). Stephen A. Forbes (1884). and Thomas Large ( 1903). Intensive Illinois ichthyology, however, began with Stephen Forbes (1844-19.30: Figure I ). the first Director of the State Laboratory of Natural History then in Normal. Illinois, and later moved to Urbana-Champaign in 1885. Sometime in the 1870s. Forbes developed the idea of producing a well-illustrated and detailed account of Illinois fishes. Year after year horse- drawn wagon parties were sent to explore and collect in different streams of the state until finally records were available for virtually every river in Illinois. The monumental effort that v\ent into the project represented the patience and toil of 30 years. The final report, ///( l-'islics (if llliiinis. appeared in 1908 417 418 Illinois Natural Histor> Survey Bulletin Vol. 34 Art. 4 Figure 1. Stephen Alfred Forbes (1844-1930). Photo courtesy of Illinois Natural History Survey. Figure 2. Location of collections of fishes made from 1876 to \W?i. From Forbes and Richardson (1908). (although no publication date is given in the volume) and was authored by Forbes and his colleague Robert Earl Richardson (1877-1935). A separate atlas of 103 range maps accompa- nied the volume. At that time. The Fishes of Illinois was considered by many to t>e the h)est regional ichthyology ever published on fishes in North America. Exceptionally skillful water colors of many species (52 in the 1908 edition, 68 in the 1 920 edition ). some never before published in color, were included and helf)ed to make the book an immediate classic. Most of the copies of the initial edition were burned in a warehouse fire, and a second edition was produced in 1920. The Forbes and Richardson data base (Figure 2) included over 200.000 fish sf>eci- mens and 1.345 collections made from about 475 localities representing all major drainages and 93 of the 1 02 counties of Illinois. A total of 142 presently valid species (Table 1 ) was recorded from Illinois waters by Forbes and Richardson [1908]. and only one (common carp. Cypriniis carpio) of those was an alien species. About 20.000 specimens used in the original Fishes ofIllinois are vouchered in the collection of the Illinois Natural History Survey. Clearly, the superb historical data base for Illinois fishes is unique and unsurpassed by that of any other state or province in North America. Subsequent to the masterful Forbes and Richardson treatise appeared works by Meek and Hildebrand (1910) on fishes of the Chicago region and another list of Illinois fishes by 0"Donnell ( 1935). which added a few species to the known fauna of the state. .A large number of collections made during the 1940s by .Aden C. Bauman. a student of Carl L. Hubbs. contributed many significant records of Illinois fishes, particularly from the southern half of the state. Bauman's collections are at the University of Michigan Museum of Zoology and have only recently been used (Lee et al. 1980: Burr and Mayde'n 1982: Warren and Burr 1989). In about 1950. Philip \V. Smith (1921- 19S6: Figure 3). fomier head of one of the Illinois Natural History Survey's scientific sections and author of The Amphibians and Reptiles of Illinois ( 1961 ). undertook to resur\e\ the fishes of the state. This task pro\ ided a unique opportunity for comparing modem-day distributional data w ith the classic w ork of Forbes and Richardson. The bulk of April IWI Symposium Proceedings: Our Living Heritage 4iy Smith's fieldwork began in the summer of 1962 and continued until the mid-1970s. During this period Smith published an account of the fishes of Champaign County (Larimore and Smith 1963), an annotated preliminary list of Illinois fishes (Smith 1965), an assessment of Illinois -Streams based on fish distribution data (Smith 1971 ), a key to Illinois fishes (Smith 1973), and finally, a new Fl.slics of llliiuiis (Smith 1979) that summarized the identification, biology, and distribution of the Illinois fish fauna. Smith and his colleagues found 199 species in Illinois (Table 1 ), made over 3,000 collections from over 2,000 localities in all of the drainages of the state and in all of the 102 counties (Figure 4). and preserved as vouchers approximately 400,000 specimens deposited at the Illinois Natural History Survey. When he compared his data with those of Forbes and Richardson, Smith ( 1971:8) found that about 70 Illinois fishes clearly showed patterns of range decimation or extirpation from the state and that 13 alien species occupied Illinois waters. Since the publication of Smith's (1979) treatise, state fish biologists have continued to collect data on the Illinois ichthyofauna. Particularly active have been ichthyologists and fish biologists from the state's universities, the Illinois Natural History Survey, the Illinois Department of Conservation, and several consulting tlmis. Additional discoveries of exotic species, native species previously unreported, and the invasion of more southerly species into Illinois waters emphasize the dynamic nature of the Illinois fauna and the need for continued collections of fishes even in presumably well-surveyed areas. DYNAMIC NATURE OF THK ILLINOIS FAUNA Illinois has many drainage systems and is bounded on the v\est b\ the Mississippi River, on the south by the Ohio River, on the east by the Wabash River, and on the northeast by Lake Michigan. The numerous interior streams, glacial lakes in Lake County, and cypress- tupelo swamps in southern Illinois account for the richness of the fauna. Illinois has the lowest average elevation of the north-central states. More than 90% of the state lies within the Central Lowlands Province, all of which was glaciated except the Driftless Area in extreme northwestern Illinois. Although well-watered. Illinois has lost many aquatic habitats to agriculture, stream impoundments, industrial and domestic pollution, and other modifications of watersheds. Disappearance of Native Species As noted previously. Smith ( 1971 :X) docu- mented range decimation or rarity for approxi- mately 70 Illinois fishes; later. Smith ( 1 979: xviii-xix) revised this number to include 52 species, some of which probably were rare even prior to European settlement. For about 1 20 species, no range change was detected. According to Smith (1971). several factors are primarily responsible for the disappearance of native Illinois fishes: 1 ) excessive siltation has cau.sed the extinction or decimation of at least 1 6 species through loss of water clarity, disappearance of aquatic vegetation, and deposition of silt over rocky or sandy sub- strates; 2) drainage of wetlands has shrunk the ranges of at least 13 .species; 3) desiccation Table L Composition of Illinois fishes over the past century. Total no. of species No. of aliens Forbes and Richardson 1 19081 Smith (1979) Present Intomialion (1990) 142' (141 native) 199 ( I S6 native) :09' (IS7 native) 1 13 No. extirpated Not applicable 9 12-' ' Forbes and Richardson |I9()S| recognized \^[) species. 142 of whicti arc considered valid today. - Additions since .Smith ( 1979) include Atlantic salmon, bighead carp, silver carp. rudd. taillighl shiner, inland silverside, threespine stickleback, striped mullet, white perch, and Rio Grande cichlid. 'The number of alien species also includes three relatively recent invaders from the south (threadfin shad, inland silverside, and striped mullet); the first two of these are also stocked as forage in Illinois reservoirs. * Extirpations since .Smith ( 1979) include bluehead shiner, bigeye chub, harlequin dancr. northern madtom. and alligator gar. The cypress minnow and greater redhorse. both included as extirpated by Smith (1979), have been rediscovered recently in Illinois, as noted in the text. 420 Illinois Natural History Survey Bulletin Vol. 34 An. 4 during drought, which has dried up once permanently flowing streams, stopped the flow in seeps and springs, and temporarily reduced the size of formerly larger rivers, has shrunk the ranges of at least 12 species; 4) interactions between species, including the effects of introduced species on native ones, competitive supplantation, and aggressive dispersal by ecologically labile species, has caused the extinction or decimation of at least 9 species; 5) industrial. dome.stic, and agricultural pollution has caused the decimation of at least 5 species; 6) dams and impoundments are responsible for the decimation of at least 4 species through the loss of a large variety of habitats and the blocking of natural migration; 7) higher water temperatures now than formerly, chiefly the result of stream channelization and the removal of marginal vegetation, have caused the decimation of at least 1 species. No single factor has as yet been identified for the extirpa- tion of the muskellunge. Eso.x nHisc/iiiiuiiitiy. from northern Illinois or the saddleback darter. Percina oiiachitae. from the Wabash River. Since the publication of Smith's book (1979). the continued decline of several species has been documented. Examples include the pallid shiner, Hyhopsis amnis. a species now known to have been much more widespread in Illinois than indicated on Smith's (1979) distribution map. It has disappeared from seven major Illinois drainages where it was known to occur from the late 1800s through the 1940s (Warren and Burr 1988). It remains in the Kankakee River drainage (Skelly and Sule 198.^) and in the upper Mississippi River (Warren and Burr 1988). The Mississippi silvery minnow, H\hoi;iiuthiis nucluilis. was not taken in the recent (late 1980s) survey of the fishes of Champaign County and was rarely taken in several recent surveys in southern Illinois where suitable habitat was present. The bigeye shiner. Notropis hoops, continues to disappear from sites of former occurrence but survives in the Little Vermilion River and the Clear Creek drainage of southern Illinois. Major impoundments (Carlyle and Shelbyville reservoirs) on the Kaskaskia River have severely limited the habitat of the western sand darter. Etlwosronui vidniiii. which is now very rare (if not extinct) in the drainage. The species has, however, been taken recently in the Mississippi River below the mouth of the Missouri River (Dimmick 198S). Figure 3. Philip Wayne Smith (1921-1986). Photo courtesv of Illinois Natural Hislors Sunev. Figure 4. Lixaiion of collections of llshes made from 19.S0IO l')78. From Smith 1979. April lyyi Symposium Proceedings: Our Living Hericage Another striking discovery emanating from Smith's (1979) survey and subsequent work was the relatively large number of Illinois fishes that have been extirpated since the original Forbes and Richardson (1908) survey As of this writing, these include eight species: Ohio lamprey, Ichthyomyzon hdclliiim: blacktm Cisco, Coregoniis niiiiipinnis: muskellunge. Eso.x masqidiioiii;}-. rosefin shiner. Lythrurus ardeiis: gilt darter, Pcirina eviJcs; saddleback darter, Peicina oiiachitae; crystal darter, Crystcillarici asprella: and spoonhead sculpin. Cotlits ricei. Even more alarming is the number of species that have disappeared since Smith (1979) began his survey in the 1960s. Examples include the bluehead shiner, Picrouotropis hiihhsi. last collected in Illinois waters in 1974 ( Burr and Warren 1986) and the bigeye chub. Hvbopsis amhlops. last collected in 1961 (Smith 1979: Warren and Burr 1988). In addition, the harlequin darter. Ethcostoma histrio. known previously from the Embarrass River, Cumberland and Jasper counties, is almost certainly extinct in Illinois, probably because of drainage alterations below Lake Charleston dam. My recent attempts ( 1987, 1988) to collect the northern madtom, Noninis sligmosus. in the Wabash drainage of Illinois have been unsuccessful. The alligator gar. Atiactosteus spatula, has not been taken in Illinois since 1965. although sufficient effort has not been expended recently to clarify its status. On a positive note, at least two species thought to have been extirpated at the time of Smith's (1979) survey have been rediscovered in Illinois. The cypress minnow. Hyhngnathus luni, is now known with certainty to be reproducing in the middle Cache River drainage (and possibly in Horseshoe Lake) in southern Illinois but is still considered extirpated from former sites of occurrence in the Big Muddy River drainage (Warren and Burr 1989). The drainage of wetlands that are used as nursery areas by the species is thought to be the main factor responsible for extirpation from the Big Muddy River. The greater redhorse, Maxasioma valciK icnnesi. thought to have been extinct in Illinois since 1901, was collected in 1985 from the Illinois River, rivermile 249(Seegert 1986) and again in 1989 from the Illinois River, rivennile 270.5. These two individuals must be part of a population residing somewhere in the upper basin. Native Species Previously Unrecorded One native fish has been added lo the state ichthyofauna since Smith's ( 1979) report. The taillighl shiner. Noimpis nunnlatiis. was discovered for the first time in Illinois in a wetland in Massac County in 1987 (Burret al. 1988). This species was captured at only 1 of 22 wetlands sampled on the lower Wabash and Ohio rivers (Burr and Warren 1987) and should be recognized as endangered in Illinois and given highest priority for protection. Species Expanding Their Ranges Because the Illinois fish data base is extensive, covers two broad historical periods, and is well vouchered. it allows us to be reasonably confident of the ranges of most native, nongame fishes within the confines of Illinois. While many species have experienced range reduc- tions in the last 90 years, a few others have expanded their ranges in response to wide- spread modification of habitats. An outstanding example is the red shiner, Cyprinclla lutrensis. a species tolerant of wide fluctuations in pH, dissolved oxygen, and thermal shock (Matthews and Hill 1977). Additionally, its adaptable feeding habits and reproductive capability (Matthews and Hill 1977) in combination with its tolerance for the above-mentioned parame- ters undoubtedly account for its success in Illinois. This species has expanded its range north into Wisconsin, up the Ohio River drainage of southern Illinois into Kentucky and the lower Wabash River, and beginning in the 1960s crossed over from Mississippi River drainages into the upper Vermilion River drainage (Page and Smith 1970), where it has continued to move downstream to Champaign County. Another example is the silverjaw minnow. Ericymha hiwcatu. which has ex- panded its range chiefiy in the Illinois River drainage. This pioneering species quickly disperses into newly dredged ditches with sandy substrates. Because Illinois streams tend to be wider and shallower than fomierly (Larimore and Smith 196.^). suitable habitat for species tolerant of these conditions has increased. Nearly all game/sport fishes and some forage species (e.g.. golden shiner. Notcmignnus crysoleucas, and fathead rninnow. Pimcphalcs pronwlas) have had their ranges expanded by numerous introductions which continue unabated in Illinois. The mosquitofish, (Jamhusia ajfinii, has been 422 llinois Natural History Sui^ey Bulletin Vol. 34 An. 4 widely transplanted in efforts to control mosquito outbreaks. The inland silverside, Menidia heryllina. was collected in 1978 from the Mississippi River at Grand Tower (a record included in a footnote by Smith [1979:21 1 ]). Beginning in 1980. this fish has been stocked as a forage species in several southern Illinois ponds and impoundments (Stoeckel and Heidinger 1989). Examples of game/sport fishes recently captured in the Illinois waters of Lake Michigan and not reported in Smith ( 1979) include the channel catfish, Ictaluriis punctaliis, and the black crappie, Pomoxis nigromaculatiis (Savitz et al. 1990). Smith ( 197 1 :8) lists another five native species whose ranges have expanded in recent times. New Records of Rare or Geographically Limited Species Collections of Illinos fishes made during the 1940s by A.C. Bauman and those made during the 1980s have revealed new records for rare or geographically limited Illinois species that expand the information in Smith ( 1979). For example, the lake sturgeon, Acipenserfulves- cens. not reported from the Mississippi River since 1966. is known from three recent records in the Mississippi (Burret al. 1988) and Ohio rivers (Burr et al. 1990). New localities for eight other uncommon Illinois fishes were included inBurretal. (1988). Dimmick ( 1988) reported the first Illinois records of the western sand darter. Etheostoma clanmu from the Missis- sippi River south of the mouth of the Missouri River; Savitz et al. (1989b) recorded the first record of the quillback. Ccirpiocles cypriniis. in the Illinois waters of Lake Michigan. Examina- tion of voucher specimens from several U.S. mu.seums has resulted in a reassessment of the ranges of the bigeye chub and pallid shiner (Warren and Burr 1988) as originally presented in Smith (1979). The Alien Component and Recent Southern Invasions Since Smith's (1979) survey, three exotics, the bighead carp, silver carp, and rudd, in addition to the four Smith reported, have been found at several localities in Illinois and, if not already established, almost certainly will be within a few years. The potential ecological effects of introduced and exotic fishes on native aquatic communities include habitat alterations (e.g.. removal of vegetation, degradation of water quality); introduction of parasites and diseases; trophic alterations (e.g., predation. competition for food): hybridization; and spatial alterations (e.g., overcrowding) (Taylor et al. 1984). Twenty-two (10.5 % ) of the total of 209 fish species in Illinois are not native to the state (Table 2). Of these, at least 13 were probably intentionally introduced, 5 spread through manmade canals in the Great Lakes drainage to the Illinois portion of Lake Michigan. 1 was an unintentional introduction, and 3 euryhaline species recently invaded from more southern latitudes. The presence of new species raises questions as to their source, their ecological role in Illinois, and their importance to human welfare. Among the 22 species, 7 are introduc- tions from Europe or Asia; 3 are from western North America; 8 are from eastern fresh waters of the Atlantic Coast, of which 3 are introduced and 5 used canals; 3 are native to the lower Mississippi basin or Gulf Coast and have entered the state naturally or by human transfer; and 1 (the cichlid) was presumably introduced accidentally with other sport fishes. Several, probably many, additional species have in the past been introduced into Illinois waters but are not known to persist. Thousands of Atlantic salmon, Salmo salar. were introduced into the Mississippi River in the late 1800s (Carlander 1954). Apparently the stockings were not successful, although several individuals collected in 1986 from the Mississippi River near Chester (Burret al. 1988) indicate that illegal stockings have apparently occurred in the river in recent decades. Grass, silver, and bighead carps have been encountered at many localities in Illinois, and the grass and bighead carps are known to be reproducing in the upper Mississippi River basin (Pflieger and Grace 1987: Pflieger 1989: Jennings^l989). A plethora of tropical and subtropical aquarium fishes have surely been released into Illinois waters (see Smith 1 1965] for examples) only to perish in the ensuing winter. One exception is the Rio Grande cichlid. ClchUisoruu cyanoi;iitiatiim. released accidentally in the mid-1980s into Powerton Lake near Pekin; individuals have been observed setting up territories in that thcmially treated lake during summer months (Rich Monzingo, piers, comm.). The ihreespine stickleback. Gasterosicits ticiilciiiits. captured twice in 1988 from the Illinois portion of Lake Michigan (at Trident Harbor and Cicero), is apparently spreading rapidU through the upper Great Lakes. It was tlrst taken in Lake Huron in April IWl Symposium Proceedings: Our Living Heriiage 423 1982 (C. L, Smith 1985:276), but whether the species is self-sustaining in Illinois waters is not known. Some of the alien species are localized geographically, rare, or small and apparently unimportant ecologically. In contrast, the salmonids, striped bass, and recently introduced carps are much valued as recreational species or for weed control, and some are common and becoming widespread. Another group of species includes the locally abundant alewife and goldfish, the widespread common carp, and the rapidly spreading rainbow smelt and white perch. These species are more or less controver- sial, being variously valued as sources of food or recreation but with negative ecological attributes (e.g., periodic alewife die-offs. predation, unfavorable ecological interactions with native species). The rainbow smelt, the most numerous small species in some winter seine samples from the Mississippi River for over 10 years, has not been collected from June through October and is probably not self- sustaining in the Illinois portion of the Missis- sippi River. The sea lamprey, an alien in Lake Michigan, has played a major role in the history and fisheries of the Great Lakes Basin. One of the most surprising invasions in Illinois was the appearance during the fall of 1989 of the striped mullet. Miifiil cephahis. in the Mississippi and Ohio rivers. This princi- pally marine species had not been reported previously from Illinois waters and was known only in the published literature as far north in Table 2. General dislribution in Illinois of alien fish species and recent invaders from southem latitudes. Numbers in parentheses indicate ( 1 ) exotics introduced directly into Illinois, (2) transplants from elsewhere in North America, (3) species colonized after introduction elsewhere or through manmade access, and (4) species that have recently invaded. Fish species by family General distribution in Illinois Petromyzontidae Peiromyzon marinus. sea lamprey (3) Clupeidae Alosa pscudohareni'iis. alewife (3) Dorosoma peienense, threadfin shad (2, 4) Salmonidae Oncorhynchus kisulch, coho salmon (2) Oncorhynchiis mykiss. rainbow trout (2) Oiunrhynchus Ishawylscha, chinook salmon (2) Salmo scikir. Atlantic salmon (2) Salmi) inula, brown trout ( 1 ) Osmeridae Osmenis morda.x. rainbow smelt (3) Cyprinidae Carassius auratus. goldfish ( I ) Clenopharyiiiiodon iik'lla. grass carp ( I ) Cypriinis caipio, common carp ( 1 ) Hypophlhalmichlhys mo/olri.x, silver carp ( 1 ) Hypiiphllhilmlchlhys nohilis. bighead carp ( I ) Scardiiiiiis erylhiophlhalmus. rudd (I) Ictaluridae Anu'iuriis cams, while catfish (2) Moronidae Morone americana. white perch (3) Morone sa.xalilis, striped bass (2) Atherinidae Menidia heiylliiui. inland silversidc (2, 4) Gastcrosleidae Gaswroslciis uciilcaliis, Ihreespine stickleback (3) Mugilidae Miit;il cephahis, striped mullet (4) Cichlidae Cichlasoma cyanoKiilialum. Rio Grande cichlid (2) L. Michigan L. Michigan Ohio R., Mississippi R., Wabash R., southem Illinois reservoirs L. Michigan northem half of Illinois L. Michigan Mississippi R. northem Illinois, L. Michigan L. Michigan, Illinois R.. Mississippi R., Ohio R. Illinois and Rock R. drainage big rivers, reservoirs, ponds statewide big rivers, reservoirs, ponds big rivers, reservoirs, ponds northem Illinois; sporadic Illinois R., Mississippi R., Kaskaskia R. L. Michigan Illinois reservoirs southem Illinois reservoirs, Mississippi R. L. Michigan Ohio R., Mississippi R. Powerton L.. Pckin 424 Illinois Natural History Survey Bulletin Vol. 34 An. 4 the Mississippi Riveras southern Arkansas (Robison and Buchanan 1988). According to William L. Pflieger (pers. comm.). striped mullets were obtained from the Mississippi River at New Madrid in 1 983 and at Cape Girardeau in 1988. The lower water levels in the Mississippi River in 1989 may have created water quality conditions (e.g., high dissolved solids) favorable for striped mullet and allowed them to reach the upper Mississippi River basin (Burretal. 1990). ENDANGERED, THREATENED, AND WATCH LIST SPECIES In the approximately 130 years since Europeans actively colonized the state of Illinois, changes in the fish fauna have been profound. Of the 187 native species (Table 1 ), a few have expanded their ranges and are now more abundant and more generally distributed than formerly, but many more have been decimated to some degree by the widespread modification of habitats and deterioration of water quality. Prior to the passage of the federal Endangered Species Act in 1973. attempts had been made (e.g., Lopinot and Smith 1973) to list species as rare or endangered on the basis of their natural rarity, restricted distribution, and paucity of habitat as well as on the basis of immediate or potential threats to their existence within Illinois (Smith 1979). After implementation of the act, terminology was revised to include the categories endangered and threatened. Since the longjaw ciscoe, Coregonus alpciiac, is no longer considered a valid species and was never officially reported from the Illinois waters of Lake Michigan, none of the Illinois species qualifies as endangered (actively threatened with extinction) in the sense of the federal definition. The Illinois Endangered Species Act of 1972 (amended in 1977) provides for some protection of rare fishes. Lists (Smith and Page 1981; Illinois Endangered Species Protection Board 1990) of endangered and threatened fishes have continued to be revised and up- dated: however, potential threats to rare fishes are always present and the status of each is constantly subject to change. A change in status can occur quickly, particularly in a peripheral or relict population. Thirteen of the 1 87 native species are endangered and 15 are threatened (Table 3). Eleven species have been placed on a watch list (Table 4), an action that suggests they may be recategorized as endangered or threatened depending on changes that take place in Illinois, A significant concern to consen ation biologists and others is the status and protection of those species that are restricted to big, free-flow ing rivers (i.e., the Mississippi River). Some of the species on the watch list are big river fishes: however, because these species do not occur generally w ithin the "inland" waters of state boundaries, they are not receiving the protec- tion they warrant. Examples of big ri\er fish needing more formal protection in Illinois include the pallid sturgeon, Scaphirhynchus albus. the tlathead chub, Platygobio oracilis. Table 3. Fishes categorized as endangered or threatened i Species Protection Board ( 1990). Nomenclature has been Burr (1991) and Warren (1989). n Illinois according to the Illinois Endangered modified where appropriate to follow Page and EndancLMed Threatened Northern brook lamprey, Ichlhyomyzon fossor Bigeye chub. Hyhopsis cimhlops Pallid shiner. Hyhopsis umiiis Pugnose shiner, Ni'IropIs ciiioiiciiKS Weed shiner. Nolropis re.xcmiis Bluehead shiner, Ptvronotiopis liiihhsi Cypress minnow. Hyh(>f;inilluis Iniyi Greater redhorse. Mo\(>sl(nnii vcilcmiciincsi Northern madtom, Noliinis sligniosiis Western sand darter, Ethcostoma cluiiim Eastern sand darter, Elhcostoma peUiicidum Bluebreast darter, Etheostoina caiminim Harlequin darter, Elhcostoma hislrio Least brook lamprey, Lampcira aepyplcra Lake sturgeon, Aripenser fiihescens Alligator gar, Alraclostciis spatula Cisco, Coregonus artedii (or arledi) Lake whitefish. Coregonus clupeaformis Bige\e shiner, \otropis hoops Ironcolor sinner. Nolropis chalrhaeus Blackchin shiner, Nolropis hctcrodon Blacknose shiner, Nolropis heierolepis Ri\er redhorse, Mo.xostoma carinalum Longnose sucker, Catoslomus calostomus Banded killifish. Funduhis diaphanus Rcds|-iolled suntlsh, Lcpoinis minialus Bantam sunfish. Lepomis symmciricus Iowa darter. Ethrosloma exile April IWI Symposium Proceedings; Our Living Heritage 425 the sturgeon chub. Macrhyhopsis ^elida. and the sickletin chub. Macrhyhopsis ntecki. These tour species are restricted in Ilhnois to the main channel of the Mississippi River below the mouth of the Missouri Ri\er. Intermittent sampling in the Mississippi River below the mouth of the Missouri River over a 12-year [jeriod indicates that the three chub species are naturally rare and sporadic in occurrence. Small numbers of the sicklefin chub are still being captured, but the flathead and sturgeon chubs have been taken once each since 1985. The pallid sturgeon is so rare throughout its range that it is being considered for listing as a federally endangered species. If species that are considered extirpated from Illinois and those on the endangered, threatened, or watch lists are included. 46 species or 249f of the native fauna are experi- encing trouble maintaining viable populations in Illinois. The addition of the taillight shiner, flathead chub, and sicklefin chub, which are presently not on any formal list, brings the total to 49 species or 26%. RECOMMENDATIONS Illinois is a model state in view of its excellent data base on fish distributions over time. Although we have learned a great deal about the effects of human activities on the aquatic environment in Illinois, we must continue to conduct basic survey work on Illinois fishes and document long-term changes in the fauna. Because fishes are sensitive indicators of environmental quality, continued collection of data will aid in monitoring a variety of stream- quality parameters and assist state agencies in Table 4. Fishes placed on the watch list by the Illinois Endangered Species Technical Advisory Committee on Fishes. These species do not receive protection under federal or state laws. Pallid sturgeon. ScapliirlniH hiis allnis Round whitefish. Prcsopiiim tylindnHciiin Lake chub. Couesius pliimhcus River chub. Nocomis micropogon Gravel chub. Erimystax x-piinctatiis Sturgeon chub. Macrhyhopsis gelicia Blacktail shiner. Cyprincllii veniisia Northern starhead topminnow. Funduhis clispcir Fourhom sculpin. Myoxaccphaliis (jiiudri( nniis Spoonhead sculpin. Culliis ricei Cypress darter. EllieosUmui procliarc identifying high-quality aquatic habitats in need of protection. Because of the number of species extirpated or endangered in Illinois, we need to establish a monitoring program and status surveys of species on the watch list. Several of the species on the Illinois endangered list are probably already extirpated (e.g.. bigeye chub, bluehead shiner) and the most effective course of action might be to allocate funds and efforts on species that may be realistically recoverable. Over the last several years, we have come to recognize that we know comparatively little about the fundamental life histories of nongame fishes in contrast to the voluminous literature on the biology of game or sport fishes. If we are ever going to manage nongame species effec- tively, more funding is needed for studies on basic fish biology, especially those emphasizing reproductive biology, trophic ecology, predator- prey interactions, and parasites and diseases. The purchase of critical habitat by The Nature Conservancy, the Illinois Department of Conservation, and other agencies has provided islands of habitat where some rare fish species can survive. For the taillight shiner, the pur- chase of critical habitat may be the best measure for protecting this rare and highly localized species. Several rare Illinois fishes that occur in relatively undisturbed and protected areas (e.g., LaRue-Pine Hills Swamp) continue to maintain viable populations. Efforts to purchase critical stream and wetland habitats in Illinois need to increase. Game and sport fishes have been stocked in Illinois waters for many years. Within reason, state agencies should now consider stocking certain nongame fishes in an attempt to restore viable populations. Pond culture of endangered and threatened species should be continued in Illinois because it has provided a useful environment for studying aspects of the fundamental life histories of rare species: this information in turn leads to more effective management. Because siltation is still considered to be the number one factor in decimation of native fish populations, we must continue to work creatively w ith tamiers and others in protecting the valuable prairie topsoil of Illinois. The removal of gravel from headwater streams should be discouraged because the process increases erosion and destroys breeding sites of headwater creek fishes. Reservoir construction 426 Illinois Natural History Survey Bulletin Vol. 34 An. 4 and stream channelization should also be discontinued in Illinois because of the detrimen- tal effects these practices have on large ex- panses of aquatic habitat. Finally, basic survey work on the big rivers of Illinois is badly needed. While we know comparatively little about the biology of small stream species, we know next to nothing regarding nongame, big river fishes. Unusual Illinois species (e.g., the pallid sturgeon) may disappear before we learn anything substantial about them or can protect them. ACKNOWLEDGMENTS I am grateful to Larry A. Jahn, William L. Ptlieger, and Lawrence M. Page for construc- tive comments on an earlier draft of this report. Kevin S. Cummings and Christine A. Mayer helped compile information on Illinois fish collections at the Illinois Natural History Survey. LITERATURE CITED Burr, B.M., and R.L. Mayden. 1980. Dispersal of rainbow smelt, Osmcriis morda.x. into the upper Mississippi River (Pisces: Osmeridae). American Midland Naturalist 104(1): 198-201. Burr, B.M., and R.L, Mayden. 1982. Status of the cypress minnow, Hyhoiiiiatlnis hayi Jordan, in Illinois. Chicago Academy of Sciences Natural History Miscellanea 215:1-10. Burr, B.M., and M.L. Warren, Jr. 1986. Status of the bluehead shiner {Nolropis huhhsi) in Illinois. Transactions of the Illinois State Academy of Science 79(1 & 2): 129-1 36. Burr. B.M., and M.L. Warren, Jr. 1987. Wetland resources of the Ohio and lower Wabash rivers—an inventory of fishes, mussels, and crayfishes. Final Report to the Illinois Department of Conservation, Division of Natural Heritage, Springfield. 85 p. Burr, B.M., M.L. Warrrn, Jr., and K.S. Cummings. 1988. New distributional records of Illinois fishes with additions to the known fauna. Transactions of the Illinois Stale Academy of Science 81(1 &2):I6.V170. Burr, B.M., M.L. Warren, Jr., O.K. Weddle, and R.R. CiCERlil.i o. 1990. Records of nine endangered, threatened, or rare Kentucky fishes. Transactions of the Kentucky Academy of Science 51 (3 & 4): 188-189, Cari.ander. H.B. 1954. History offish and fishing in the upper Mississippi River. Upper Mississippi River Conservation Committee. 96 p. DiMMicK. WW. 1988. Discovery of the western sand darter, Anunocrypia clara. in the Mississippi River below the confluence of the Missouri River. Transactions of the Illinois State Academy of Science 81(1 &2):2! 1-212. Forbes, S.A. 1 884. A catalogue of the native fishes of Illinois. Repon of the Illinois State Fish Commis- sioner for 1884. pp. 60-89. Forbes. S.A.. and R.E. Richardson. [1908]. The fishes of Illinois. Illinois State Laboratory of Natural History, cxxxi -i- 357 p. plus separate atlas containing 103 maps. Forbes. S.A., and R.E. Richardson. 1920. The fishes of Illinois. 2nd ed. Illinois Natural History Survey, cxxxvi + 357 p. Illinois Endangered Species Protection Board. 1990. Checklist of endangered and threatened animals and plants of Illinois. Illinois Department of Conservation, Springfield. 26 p. Jennings, D. 1989. Exotic species update. National Fisheries Research Center. Gainesville, FL. 3 p. Jordan, D.S. 1878. A catalogue of the fishes of Illinois. Illinois State Laboratory of Natural History Bulletin l(2):37-70. Kennicott, R. 1855. Catalogue of animals observed in Cook County, Illinois. Transactions of the Illinois State Agricultural Society 1:577-595. Large, T. | 1903]. A list of the native fishes of Illinois, with keys. Appendix to Report of the State Board of Fish Commissioners for Sept. 30, 1900 to Oct. 1, 1902. 30 p. Larimore, R.W.. AND P.W. Smith. 1963. The fishes of Champaign County. Illinois, as affected by 60 years of stream changes. Illinois Natural History Survey Bulletin 28(2''):299-382. Lee, D.S., C.R. Gilbert. C.H. Hoci tt, R.E. Jenkins, D.E. McAllister, and J.R. Stai ffer, Jr. 1980 et seq. Atlas of North American freshwater fishes. North Carolina State Museum of Natural History, Raleigh, x -i- 867 p. Lopinot, A.C. and P.W. Smith. 1973. Rare and endangered fish of Illinois. Illinois Department of Conservation, Division of Fisheries. 53 p. Matthews. W.J., and L.G. Hill. 1977. Tolerance of the red shiner, Nolropis liitrensis (Cyprinidae) to en- vironmental parameters. The Southwestern Naturalist 22(l):89-98. April :WI Symposium Proceedings: Our Living Heritage 427 Meek, S.E.. and S.F. Hildebrand. 1910. A synoptic list of the fishes known to occur within 30 miles of Chicago. Field Museum of Natural Histoid Zoologi- cal Series Publications 7(9):223~338. Nelson. E.W. 1 876. A partial catalogue of the fishes of Illinois. Illinois Museum of Natural History Bulletin 1 ( I ):33-52: also Illinois State Laboratory of Natural History Bulletin 1 ( 1 ):33-32. 0"DoNNELL. D.J. 1935. Annotated list of the fishes of Illinois. Illinois Natural History Survey Bulletin 20(5):473-500. Page. L.M.. and B.M. Burr. 1991. A field guide to freshwater fishes. North America north of Mexico. Houghton Mifflin Co., Boston, (in press) Page, L.M.. and R.L. Smith. 1970. Recent range ad- justments and hybridization of Nnnopis liiirensis and Notropis spilopienis in Illinois. Transactions of the Illinois State Academy of Science 63(3): 264-272. Pflieger, W.L. 1989. Natural reproduction of bighead carp (Hypophtluilmichthys nohilis) in Missouri. American Fisheries Society, Newsletter of the Introduced Fish Section 9(4):9-10. Pflieger, W.L., andT.B. Grace. 1987. Changes in the fish fauna of the lower Missouri River, 1940-1983. Pages 166-177 in W.J. Matthews and D.C. Heins, ed. Community and evolutionary ecology of North American stream fishes. University of Oklahoma Press, Norman, viii + 310 p. Robison, H.W., andT.M. Buchanan. 1988. Fishes of Arkansas. University of Arkansas Press, Fayette- ville. 536 p. Savitz, J., C. Aiello, and L.G. Bardygula. 1989a. The first record of the white perch {Moroiie ameri- cana) in Illinois waters of Lake Michigan. Transac- tions of the Illinois State Academy of Science 82 (1 &2):57-5X. Savitz, J.. S. Arango, L.G. Bardygula. and L. ScoMA. 1990. The first records of three fish species in Illinois waters of Lake Michigan: longear sunfish (Lepomis me^alotis pella.sles). black crappie (Pomoxis nigromaculatus), and the channel catfish (ktalunis punctatiis). Transactions of the Illinois State Academy of .Science 83( 1 & 2): 1 14-1 15. Savitz, J., L G. Bardygula, and L. Scoma. 1 989b. The first record of the quillback carpsucker iCarpioclcs cypriniis) in Illinois waters of Lake Michigan. Transactions of the Illinois State Academy ofScience82{3&4):191. Seegert. G. 1986. Rediscovery of the greater redhorsc (Moxosliinui vdlciH icnncsi Jordan) (Cyprinifomies: Catostomidae) in Illinois. Transac- tions of the Illinois State Academy of Science 79 (3 & 4):29.V294. Skelly. T.M.. and M.J. Site. 1983. The pallid shiner. Notropis cimnis Hubbs and Greene, a rare Illinois fish. Transactions of the Illinois State Academy of Science 76( 1 & 2): 1 3 1- 140. Smith. C.L. 1985. The inland fishes of New York state. New York State Department of Environmental Education, Albany. 522 p. Smith, P.W. I96I . The amphibians and reptiles of Illinois. Illinois Natural History Survey Bulletin 28 (I): 1-298. Smith, P.W. 1965. A preliminary annotated list of the lampreys and fishes of Illinois. Illinois Natural History Survey Biological Notes 54. 12 p. Smith, P.W. 1971. Illinois streams: a classification based on their fishes and an analysis of factors responsible for disappearance of native species. Illinois Natural History Survey Biological Notes 76. 14 p. Smith, P.W. | 1 973 1. A key to the fishes of Illinois. Illinois Department of Conservation, Division of Fisheries, Fishery Bulletin 6. 43 p. Smith, P.W. 1979. The fi.shes of Illinois. University of Illinois Press, Urbana. 314 p. Smith, P.W., and L.M. Page. 1 98 1 . Endangered and threatened fishes. Pages 5-20 //; M. Bowles, ed. Endangered and threatened vertebrate animals and vascular plants of Illinois. Illinois Department of Conservation. 189 p. -i- vi appendices. Stoeckel, J.N., and R.C. Heidinger. 1989. Repro- ductive biology of the inland silverside. Menidia heryliiiui in southern Illinois. Transactions of the Illinois State Academy of Science 82(1 & 2):59-69. Taylor, J.N., W.R. Courtenay, Jr., and J. A. McCann. 1984. Known impacts of exotic fishes in the continental United Slates. Pages 322-373 //; W.R. Courtenay, Jr., and J.R. Stauffer, Jr., eds. Distribu- tion, biology, and management of exotic fishes. Johns Hopkins University Press, Baltimore. Warren, M.L., Jr. 1989. Geographic variation of the spotted sunfish, Lepomis pumlatus complex (Cen- trarchidae), with recognition of phylogenetic species. Ph.D. thesis. Southern Illinois University at Carbon- dale. 283 p. Warren, M.L., Jr.. and B.M. Burr. 1988. Re- assessment of the Illinois ranges of the bigeye chub. Hyhopsis amhiops. and the pallid shiner, Notropis amnis. Ohio Journal of Science 88(5):I8I-I83. Warren. M.L.. Jr.. and B.M. Burr. 1989. Distribution, abundance, and status of the cypress minnow. Hyhoi^mithus luiyi. an endangered Illinois species. Natural Areas Journal 9(3): 163-168. The Aquatic Mollusca of Illinois Kevin S. Cummings, Illinois Natural History Survey Illinois has historically supported a diverse aquatic molluscan fauna, numbering over 175 species and occupying almost every type of aquatic habitat from the Great Lakes to wet- lands, temporary woodland ponds, seeps, springs, and streams. Two classes of mollusks are represented in the waters of Illinois: Bivalvia. which includes the clams and mussels, and Gastropoda, represented by the snails and limpets. The native bivalves of Illinois are members of three families: the Mar- garitiferidae and Unionidae (the freshwater mussels) and the Sphaeriidae (the fingernail clams and peaclams). The gastropods are divided into two subclasses. Prosobranchia and Pulmonata. The Prosobranchs or the opercu- lated. gill-breathing snails are represented in Illinois by 37 species in six families. The Pulmonates or the nonoperculated, lung- breathing snails contain 37 species in four families. A list of the species for each of the families reported from the state is given on pages 433-438. For the unionids. aspects of their biology, commercial use. and status are discussed. Infonnation on identification, distribution, and biology of the aquatic mollus- can fauna of Illinois will appear in forthcoming publications. An excellent monograph on the freshwater snails of North America has been published (Burch 1989) and should be con- sulted for keys and figures of most of the species found in Illinois. The list of the freshwater mussels of Illinois (pages 435-436) is based on the exami- nation of specimens in collections housed in the following museums: Academy of Natural Sciences. Philadelphia: Chicago Academy of Sciences: Field Museum of Natural History: Illinois Natural History Survey: Illinois State Museum; Museum of Comparative Zoology. Harvard; Ohio State Llniversity Museum of Zoology; Llniversity of Illinois Museum of Natural History; University of Michigan Museum of Zoology: and the United States National Museum. The list for Sphaeriidae and Gastropoda (pages 436—i38) were compiled from the literature on Illinois Mollusca. primarilv the publications of Baker ( 19(X). 1901. 1902. 1906. 1922): Basch ( 1963); Burch (1989); Dexter (1956); Ulffers (1855); and Zetek (1918). Additional work is planned to verify the sphaeriid and gastropod lists by examining specimens in museum collections. Nomenclature in this paper, w ith three exceptions, follows a list of common and scientific names of mollusks prepared by the Committee on Scientific and Vernacular Names of Mollusks of the Council of Systematic Malacologists, American Malacological Union (Turgeon et al. 1988). Subspecies are not recognized, nomenclature for members of the Pli'wohema cordatitm species complex follows Stansbery ( 1983). and nomenclature for the family Hydrobiidae follov\ s Hershler and Thompson (1987) and Hershler et al. (1990). The aquatic mollusks of Illinois have been studied for over 150 years. Thomas Say, the first scientist to work on mollusks in Illinois, was one of .America's earliest natural- ists. Say traveled to the Midwest as early as 1817 and in 1826 mo\ed from Philadelphia to the Utopian communit\ of New Hamtony. Indiana (Van Clea\e 1951 ). While there, he collected and described many of the mollusks found in the Wabash River and its tributaries, some of which are are still recognized toda\. Few attempts ha\e been made to compile a list of the mollusk species found in Illinois. In 1906, Frank C. Baker published an annotated checklist of the Mollusca of Illinois in w hich he summarized the a\ ailable data on the distribu- tion of the species within the state. .A prolific wTiter. Baker published over 400 papers, including man\ important works on the molluscan fauna o'( Illinois (Baker 1897, 1898. 1899. 1900. 1901. 1902. 1906. 1922, 1926). Baker's papers remain the best source of published inlonnalion on the biology and 428 April 1991 Symposium Proceedings: Our Living Heritage 429 distribution of aquatic niollusks in the state. Other early wori<.ers on the freshwater mollusks of Ilhnois included Kennicott (1855); Differs (1855); Calkins (1874a, 1874b. 1874c); Strode (1891. 1892); Wilson and Clark (1912): Danglade ( 1912, 1914); Zetek (1918); and Hinkley (1919). Few papers were published on the aquatic Mollusca of Illinois in the 1930s and 1940s. During the late 1940s and 1950s, Dr. Max R. Matteson of the University of Illinois collected mussels at over 200 sites in Illinois and amassed one of the largest and best docu- mented collections that exists for any state in the nation. Matteson's surveys provided both distribution and abundance data on mussels from Illinois streams, many of which had not been previously sampled. His collections, now at the Illinois Natural History Survey, provide an invaluable data set and serve as the bench- mark for mussel surveys conducted today. In 1967. Paul W. Parmalee of the Illinois State Museum published The Fresh-water Mussels o) Illinois, which included many original observations on the distribution and habitat of unionids. This monograph, one of the most frequently cited regional works on freshwater mussels, is still the best guide available on the mussels of the state. Other papers on aquatic mollusks of Illinois in the 1950s and 60s include van der Schalie and van der Schalie (1950); Dexter ( 1953. 1956); Parmalee (1955, 1956); Matteson (1961); Matteson and Dexter ( 1966); and Fechtner (1963). In the 1970s and 1980s, stream surveys were conducted on the Illinois (Starrett 1971), Kankakee (Lewis and Brice 1980; Suloway 198 1 ), Kaskaskia (Suloway et al. 1981 ). and Wabash rivers (Meyer 1974; Clark 1976). These and current studies document the rapid decline of the freshwater mussels of Illinois and provide data on the status of rare species. BIVALVIA: MUSSFXS AND CLAMS Freshwater mussels in the families Margariti- feridae and Unionidae are found throughout the holarctic region but reach their greatest diversity in eastern North America, where they number about 285 species (Turgeon et al. 1988). A total of 78 species in two families and four subfamilies has been recorded from Illinois and boundary waters (pages 435-436). Biology. Mussels filter-feed on plankton, which they remove froin the water as it circulates through the animal via incurrent and excurrent aperatures. In most freshwater mussel species, the sexes are separate. Sperm are released into the water and taken into the female via the incurrent aperature. The eggs are fertilized and develop into an intermediate stage, the glochidium. Glochidia are stored in the female's gills, which function as brood chambers. Nearly all unionids must pass through a parasitic phase in order to complete their life cycle. In the spring or summer, glochidia are expelled into the water and must come in contact with the appropriate host, usually a fish, to which they attach and metamorphose into a juvenile mussel. Glochidia are either internal parasites on the gills or external parasites on the fins. Some species are host specific, but others are general- ists and use a wide variety of fishes as hosts. Mussels are long lived. Many species live as long as 25 years, and some are reported to live more than 50 years. Commercial Use. In 1891 a Gemian immigrant, J.F. Boepple of Petersburg, Illinois, realized that the mussels of the United States could be used, as they had been in Europe, to manufacture buttons. In the early part of the twentieth century, enormous quantities of mussels were harvested for the button industry, with some beds in Illinois producing over 700 tons in a single year (Coker 1919). Mussel shells were collected, cooked out, and shipped to factories where they were cut into blanks, sorted, polished, and finished into buttons. Today freshwater mussel shells are exported to Japan where they are converted into beads and inserted into oysters where they serve as nuclei for cultured pearls. The oysters are maintained in cages under water, and over a period of about a year, a layer of mother-of-pearl is secreted around the bead to form the pearl. From 1912 to 1914, roughly 15,000 tons of shells were taken in Illinois and boundary waters and sold at a price that varied from .S4 to $10 a ton. The increase in price over the last 75 years has been astronomical. In the 1940s, the price of shells was about $25 a ton and re- mained at that level until the button industry collapsed in the late 195()s due to the advent of plastics. As the demand for shells to manufac- ture cultured pearls increased, so did the price, from $45 a ton in the 60s, $800 in the 7()s, and 430 Illinois Natural History Survey Bulletin Vol. 34 An. 4 $1,800 in the 80s. to $2,400 a ton this year (N. Cohen, pars. comm.). At current prices, the estimated harvest of 1912 to 1914 would be worth about $36 million. Status. Surveys across North America have documented significant declines in freshwater mussel populations. Recent surveys for mussels in Illinois using the same methods as those of previous studies have documented a reduction in the fauna for all streams sampled (Table 1). In 1966. William C. Starrett of the Illinois Natural History Survey conducted an in-depth study of the Illinois River. He col- lected only 23 of the 47 species previously reported from the Illinois (Starrett 1971). Two of the 24 extirpated species were the butterfly. Ellipsaria lineolata (Rafinesque 1820), a species that has declined statewide in recent years; and the Higgins eye, LampsiUs hii^ginsi (Lea 1857), now on the federally endangered species list. Similar results were obtained in the Kankakee River where Suloway ( 1 98 1 ) reported only 24 of the 32 species historically known to inhabit the river. The Kankakee River drainage continues to support some of the richest mussel populations of the state, includ- ing the state threatened bullhead, Plethohasiis cyphyus (Rafinesque 1820), and the ellipse, Vemistacouclui ellipsiformi.s (Conrad 1836). In the Kaskaskia River, the decline in diversity has been pronounced. Only 32 of the 39 species recorded from the drainage were found in 1956. and that number was reduced to 24 by 1978 (Suloway et al. 1981 ). In addition, the number of individuals dropped from 2.595 to 498. an 80% reduction in just over 20 years. A survey of the Sangamon River in 1988-1989 recov- Table 1. Selected streams in Illinois where recent surveys have documented declines in the freshwater mussel fauna. Data from Starrett 1971; Suloway et al. 1981; Suloway 1981; and Cummings et al. un- published. April iw: Symposium Proceedings: Our Living Heritage 431 ered to be globally extinct, including four once found in Illinois (Turgeon el al. 1988; see listing on pages 435-436, this publication). On the federal level, 37 mussels are listed as en- dangered and another 56 are proposed or candi- dates for listing (U.S. Department of the Interior, Fish and Wildlife Service 1989a, 1989b). The Illinois Threatened and Endan- gered Species List now contains 33 mussels (29 endangered and 4 threatened), slightly over 40% of the species ever recorded from Illinois (Illinois Endangered Species Protection Board 1990). Another 1 1 species are candidates or species of special concern that may be listed in the future. These bring the total number of rare, endangered, or extirpated species in Illinois to 44 species—56% of the state's known mussel fauna. Other states have similar problems. North Carolina, for example, recently reported that half of its mussel species are disappearing and in need of protection (Venters 1990). This national decline has received some much needed attention and funding has been provided in recent years to begin to document and address the problem. The fingernail clams and peaclams of the family Sphaeriidae are holarctic in distribution and occupy a wide variety of habitats. Thirty- eight species in four genera are found in North America, and 26 species in three genera are reported from Illinois (pages 436-437). Al- though little has been published on the distribu- tion and status of these animals in Illinois since Baker's list of 1906, unpublished reports make clear that many species have disappeared from the streams in which they fonnerly occurred and are declining throughout their range. Sphaeriids are hermaphroditic and, unlike freshwater mussels, have direct development, with about 2 to 20 young produced per female. Although sphaeriids have no direct economic value, they are an important food source for many animals, including fishes and diving ducks. The family Corbiculidae is represented in Illinois by the exotic Asian Clam, Cdihiciilu fluminea (Miiller 1774). Introduced in North American in the I92()s (Counts 1981 ), this species was first reported in Illinois froin the Ohio River in southern Illinois in the early 196()s (Eechtner 1962). Since then it has spread at least as far north as Rock Island and is present in inost if not all drainages in the state. As is the case with most established exotics, Corhlciila has had serious negative effects on the environment. This extremely prolific clam has caused major problems associated with the fouling of cooling water intakes of power plants (Isom 1986) and may outcompete native species (Clarke 1988). The family Dreissenidae is represented in North American freshwaters by the zebra mussel Drcisscna polyniorplia (Pallas 1 77 1 ). Although the zebra mussel is not currently established in Illinois waters, it was recently discovered in the Indiana portion of Lake Michigan and its arrival here is imminent. This exotic is causing tremendous economic problems in Lake Erie and Lake St. Clair and will negatively affect our native mus.sels by smothering and suffocating them as it has in the Great Lakes. GASTROPODA: FRESHWATER SNAILS Freshwater snails are basically herbivores and detritivores and use their radulae to scrape algae and diatoms from plants and rocks. About 500 species of freshwater snails are found in North America, 350 Prosobranchs and 150 Pulmonates (Burch 1989). Of those, 85 or about one-fifth of the species are candidates for federal protection (U.S. Department of Interior, Fish and Wildlife Service 1989b). A review of the literature suggests that there are or were about 74 species of freshwater snails in Illinois, two of which were introduced and three that are under consideration for federal listing (pages 437-438). The subclass Prosobranchia is repre- sented in Illinois by 37 species in six families: Valvatidae, Viviparide, Bithyniidae, Hydro- biidae, Pomatiopsidae, and Pleuroceridae. The shells of North Ainerican Valvatidae are relatively small (up to 5 mm) and flattened in shape. Valvatids are egg layers and, unlike most Prosobranchs, hemiaphroditic. Five species, all in the genus Wihaki. have been reported from Illinois. The family Viviparidae is found on all continents except Antarctica and South America and occurs throughout eastern North America. The sexes are separate, and as their name implies, they are "live bearers" as opposed to egg layers. Six species in three genera are found in Illinois. 432 Illinois Natural HiMor)' Survey Bulletin Vol. 34 An. 4 The family Bithyniidae is represented in Illinois by the Mud Bithynia. Blihyiiia lentacu- lata (Linnaeus 1758). This specie.s also occurs in Europe, and populations have been intro- duced into North America where the species has spread widely (Burch 1989). Bithynia teii- laciiUita has been reported from Pleistocene deposits in Chicago, and it may, therefore, have been present in North America before Europe- ans arrived. The family Hydrobiidae is one of the most common and widely distributed snail families in the world. These small- to medium- sized snails are a major component of the North American fauna and number about 35 genera and 170 species (Hershler and Thompson 1987; Turgeon et al. 1988). Most live in fresh water, although a few have been found in brackish water. Twelve species in seven genera have been repotted from Illinois. The family Pomatiopsidae is represented in North America by six species, two of which are found in Illinois. These snails are usually regarded as amphibious, inhabiting river banks or moist areas near streams. The Pleuroceridae are widely distributed, occurring in North, Central, and South Atnerica and in Africa and Asia. They reach their greatest diversity, however, in the southeastern United States. Pleurocerids are extremely sensitive to the effects of pollution and silta- tion. At least 23 species are presumed extinct, and many others are candidates for threatened or endangered status (Turgeon et al. 1988: U.S. Department of the Interior, Fish and Wildlife Service 1989b). Eleven species in four genera have been found in Illinois, three of which are candidates for federal listing (page 437). Their current status in Illinois is unknown and needs investigation. The subclass Pulmonata is represented in Illinois by four families. Like the pleurocerids, members of the family Lytnnaeidae are found worldwide but reach their greatest diversity in North America. Fourteen species ( 1 introduced) in six genera have been reported from Illinois. The fatnily Physidae is mainly a New World fatnily with a few species found in Eurasia and Africa. Physids are found in a w ide variety of habitats and are the most widespread and abundant snails in North America. They appear to be the most pollution tolerant of all freshwater niollusks and may be the otiK species foiuul in highly degraded waters. The family Planorbidae is restricted to fresh water and is worldw ide in distribution. Planorbids vary widely in size from about 1 to 30 mm. A few species are known to serve as intermediate hosts for human parasites and have been studied extensively: most others are relatively unknow n ecologically. Twelve species ( 1 introduced) in six genera have been found in Illinois. The Ancylidae. or freshwater limpets, are worldwide in distribution and are found in many freshwater habitats. The family, revised in 1963, is currently thought to contain about 13 species in four genera (Basch 1963: Turgeon et al. 1988). Ancylids can usually be found attached to aquatic vegetation or living on stones or other debris. Little is know n about the biology of freshwater limpets, but they are reported to be fairly intolerant of chemical pollution (Basch 1963). Six species in three genera have been found in Illinois. The current distribution and status of gastropods in Illinois are poorly understood, and as a result we are unable to compile a list of threatened or endangered freshwater snail species for the state. Given the documented decline in freshwater mussels and other aquatic organisms, however, there can be little doubt that Illinois has lost and is likeh in danger of losing many species of snails as well. Conservation efforts in Illinois and other states have thus far concentrated on preser\ ing or protecting terrestrial ecos\ stems and their inhabitants. While the protection of prairies, bogs, fens, glades, and forests is an extremely important and worthwhile endeavor, we need to protect aquatic habitats as well or we will most certainl) lose man\ of the fascinating and unique species that are found in the fresh waters of North America. ACKNOWLED(,MENTS I would like to thank the follow ing curators and collection managers for allowing me access to collections under their care: Arthur E. Bogan and George M. Da\ is. The .Acadenn of Natural Sciences of Philadelphia: Ron N'asile, The Chicago Academv of Science: Margaret Baker and the late .Alan Solem, Field Museum of Natural History: Tim Cashatt, Illinois State Museum: Kenneth Boss, Sih ard P. Kool, and Richard 1. .lohnson. Museutn of Comparative Zoolocv. llarxaid Uni\ersit\: John B. Burch. April IWl Symposium Proceedings: Our Living Heritage 433 Douglas J. Eemisse, and Walter R. Hoeh, University of Michigan Museum of Zoology; David H. Stansbery and Kathy G. Borror. Ohio State University Museum of Zoology; Robert Hershler. U.S. National Museum: and Lowell Getz and Thomas Uzzell, University of Illinois Museum of Natural History. Robert W. Schanzle, Illinois Department of Conservation, and Carol Stein. Ohio State University Museum of Zoology, provided helpful comments on the manuscript. LITERATURE CITED Baker, F.C. 1897. On a collection of mollusks from Grand Tower, Illinois. Nautilus 1 1(3):28-30. B.AKER. F.C. 1898. The Mollusca of the Chicago area. Pan 1: The Pelecypoda. Chicago Academy of Sciences Bulletin 3( I ):1-I3(). Baker. F.C. 1899. Notes on the mollusks of Lilycash Creek. Nautilus 12(3):30-31. Baker, F.C. 1900. A revision of the Physae of northeastem Illinois. Nautilus 14(2):16-24. Baker. F.C. 1901. A revision of the Limnaeas of northern Illinois. Transactions of the Academy of Science of St. Louis 1 1(1): 1-24 + 1 plate. Baker, F.C. 1902. The Mollusca of the Chicago area. Part 2: The Gastropoda. Chicago Academy of Sciences Bulletin 3(2): 131-418 + 9 plates. Baker. F.C. 1906. A catalogue of the Mollusca of Illinois. Bulletin of the Illinois State Laboratory of Natural History 7(6):53-136 + I map. Baker. F.C. 1922. The molluscan fauna of the Big Vermilion River. Illinois. Illinois Biological Monographs 7(2): 1 05-224 + 15 plates." Baker. F.C. 1926. The naiad fauna of the Rock River system: a study of the law of stream distribu- tion. Transactions of the Illinois Stale Academy of Science 19:103-112. Basch. P.F. 1963. A review of the recent freshwater limpet snails of North America {Mollusca: Puhnon- ata). Bulletin of the Museum of Comparative Zoology. Harvard University 129(8):399-461. Blrch. J.B. 1989. North American freshwater snails. Malacological Publications. Hamburg. Ml. viii + 365 p. Calkins. W.W. 1874a. The land and fresh water shells of LaSalle County. Ills. Proceedings of the Ottawa Academy of Science. 48 p. + 1 plate. Calkins. W.W. 1874b. Notes on freshwater Mollusca. found in the vicinity of Chicago. Illinois. Cincinnati Quarterly Journal of Science 1:242-244. Calkins. W.W. 1874c. Notes on the molluscan fauna of northern Illinois. Cincinnati Quarterly Journal of Science 1:321-325. Clark. C.F. 1976. The freshwater naiads of the lower end of the Wabash River, Mt. Camiel. Illinois, to the south. Sterkiana 61:1-14. Clarke. A.H. 1988. Aspects of Corbiculid-unionid sympatry in the United Slates. Malacology Data Net 2(3&4):57-99. Coker, R.E. 1919. Fresh-water mussels and mussel industries of the United States. Bulletin of the U.S. Bureau of Fisheries 32: 1 3-89. Counts, C.L. III. 1981. Corhinila fliwiiiwa (Bi- valvia: Corbiculidae in British Columbia. Nautilis 95(1):12-13. Danglade, E. 1912. Condition of the mussel fishery of the Illinois River. U.S. Bureau of Fisheries Economic Circular 2:1-4. Danglade. E. 1914. The mussel resources of the Illinois River. U.S. Bureau of Fisheries. Appendix 6 to the report of the U.S. Commissioner of Fisheries for 1913. 48 p. -f 5 plates + 1 map. Dexter, R.W. 1953. The mollusks inhabiting some temporary pools and ponds in Illinois and Ohio. Nautilus 67(l):26-33. Dexter. R.W. 1956. Comparison of the gastropod fauna in the drainage systems of Champaign County, Illinois. American Midland Naturalist 55(2); 363-368. Fechtner, F.R. 1962. Corhicida fliiminea (Miiller) from the Ohio River. Nautilus 75(3): 1 26. Fechtner, F.R. 1963. Checklist of east central Illinois Unionidae. Nautilus 76:99-101. Hershler, R.. and F.G. Thompson. 1987. North American Hydrobiidae (Gastropoda: Rissoacea): redescription and systematic relationships of Trxonia Stimpson. 1865. and Pxrgidopsis Call and Pilsbry. 1886. Nautilus 101(l):'25-32. Hershler. R.. J.R. Holsinger, and L. Hubricht. 1990. A revision of the North American freshwater snail genus fw)//.i,'f/).v (Prosobranchia: Hydrobiidae). Smithsonian Contributions to Zoology 509. 49 p. Hinkley, a.a. 1919. Mollusca found in the vicinity of DuBois, Illinois. Nautilus 33( 1 ): 1 4- 1 7. Illinois Endangered Species Protection Board. 1990. Checklist of endangered and threatened animals and plants of Illinois. April 1990. ii + 26 p. 434 Illinois Natural History Survey Bulletin Vol. 34 .An. 4 IsoM. B.G. 1986. Historical review of Asiatic clam (CorhiciiUi) invasion and biotouling of waters and industries in the Americas. Proceedings of the Second International Cnrhicida Symposium. Special Edition 2 of the American Malacological Bulletin. 1986:1-5. Kennicott. R. 1855. Catalogue of animals observed in Cook County, Illinois. Transactions of the Illinois State Agricultural Society 1( 1853-1 854):577-595. Lewis, R.B., and J.R. Brice. 1980. A comparison of the past and present freshwater mussel fauna of the Kankakee River in Illinois. Natural History Miscel- lanea 21 1:1-7. Matteson, M.R. 1961. A comparative study of two unionid populations of the lower Rock River. Transactions of the Illinois State Academy of Science 54(1 & 2):54-60. Matteson. M.R.. and R.W. Dexter. 1966. Changes in pelecypod populations in the Salt Fork of the Big Vermilion River. Illinois, 1918-1962. Nautilus 79(3):96-101. Meyer, E.R. 1974. Unionid mussels of the Wabash. White, and East Fork White rivers. Indiana. Virginia Journal of Science 25( 1 ): 20-25. Parmalee, P.W. 1955. Some ecological aspects of the naiad fauna of Lake Springfield. Illinois. Nautilus 69(l):28-34. Parmalee, P.W. 1956. A comparison of past and present populations of fresh-water mussels in southern Illinois. Transactions of the Illinois State Academy of Science 49:184-192. Parmalee. P.W. 1967. The fresh-water mussels of Illinois. Illinois State Museum Popular Science Series. Vol. 8. 108 p. SCHANZLE, R.W., AND K.S. CuMMINGS. 1991. A survey of the freshwater mussels (Bivalvia: LInionidae) of the Sangamon River basin. Illinois. Illinois Natural History Sur\'ey Biological Notes 137. (in press) Stansbery, D.H. 1983. Some sources of nomencla- torial and systematic problems in unionid mollusks. Pages 46-62 in A.C. Miller, compiler. Report of Freshwater Mussels Workshop. 26-27 October 1982. U.S. Arms Engineer Waterways Experinienl Station. Vicksburg, MS. Starrett. W.C. 1971. A sur\cy ol the mussels (Unionacea) of the llhnois Ri\er: a polluted stream. Illinois Natural History Survey Bullctm 30(5): 267-403. Strode, W.S. 1891. Mollusks of Thompson's Lake, Illinois. Nautilus 4( 1 2): 1 33-1 .^4. Strode. W.S. 1892. The Unionidae of Spoon River. Fulton County. Illinois. American Naturalist 26:495-501. Slloway, L. 1981. The unionid (Mollusca: Bivalvia) fauna of the Kankakee River in Illinois. American Midland Naturalist 105(2):233-239. Slloway. L.. J.J. Slloway. and E.E. Herricks. 198 1 . Changes in the freshwater mussel (Mollusca: Pelecypoda: Unionidae) fauna of the Kaska.skia River. Illinois, with emphasis on the effects of impoundment. Transactions of the Illinois State Academy of Science 74( 1 & 2):79-90. TuRGEON, D.D.. A.E. Bogan. E.V. Coan. W.K. Emerson, W.G. Lyons. W.L. Pr.att. C.F.E. Roper. A. Scheltema, F.G. Thompson, and J.D. Williams. 1988. A list of common and scientific names of aquatic invertebrates from the United States and Canada: mollusks. American Fisheries Society Special Publication 16. viii -i- 277 p. -t- 12 plates. Ulfftrs. H.A. 1855. Mollusca of southern Illinois. Transactions of the Illinois State Agricultural Society 1( 1853- 1854 ):6 10-6 12. U.S. Department of Interior, Fish and Wildlife Sermce. 1989a. Endangered and threatened wildlife and plants. 50 CFR Part 17.1 1 and 17.12. January 1. 1989. 34 p. U.S. Department of Interior, Fish and Wildlife Sermce. 1989b. Endangered and threatened wildlife and plants; annual notice of review. 50 CFR Part 17. Federal Register 54(4):554-579. Van Cleave. H.J. 1951. The New Harmony venture and its relation to Natural Science. Bios 22(4); 263-275. VAN der Schalie. H.. and a. van der Sch.alie. 1950. The mussels of the Mississippi Ri\er. American Midland Naturalist 44(2):448-466. Venters. V. 1 990. Freshw ater mussels disappearing from state's waters. Wildlife in North Carolina 54(4);28. Wilson. C.B.. and H.W. Cl.^rk. 1912. The mussel fauna of the Kankakee basin. U.S. Bureau of Fisheries Document 758. 52 p -( 1 map. Zetek. J. 1918. The Mollusca of Piatt. Champaign. and Vennilion counties of Illinois. Transactions of the Illinois Stale .Acadenn of Science 1 1:151-182. April lyyi Symposium Proceedings: Our Living Heritage 435 The Aquatic Mollusca of Illinois. Species are arranged aiphabeiicalh \\ iiliiii each laiiills or in the case of Unionidae within each subfamily. Abbreviations for status are as follows: (ii = extinct, X = extirpated from Illinois. FE = federally endangered. FC = federal candidate. SE = state endangered. ST = state threatened. SC = stale candidate (watch list). 1 = introduced. Scientific Name Common Name Status CLASS BIVALVIA Order Unionoida Family Margaritiferidae ( I species) Subfamily Cumberlandinae Cwnhi'i'hiitdia moiwdonta (Say 1829) Family Unionidae (77 species) Subfamily Ambleminae Amhlenui plicata ( Say 1817) CycloiKiias liiheniilahi (Rafinesque 1820) EUiplio irassidcns (Lamarck 1819) Elliplio dilcilciki (Rafinesque 1820) Fusionaia cheiiii (Lea 1831 ) Fusioiuiia fliiva (Rafinesque 1820) Fusconaia siihroriindii (Lea 1 83 1 ) Hcmistena lata (Rafinesque 1820) Me!;alonaias nervosa (Rafinesque 1820) PU'lluihasiis cicaliicosiis (Say 1829) Pk'lhohasus cooperianiis (Lea 1834) Plclluihasiis cyphyiis (Rafinesque 1820) PIciirobenui clava (Lamarck 1819) Plciiroheiua cordauim (Rafinesque 1820) Pk'wohenui plenum (Lea 1840) Pleurohema nihnini (Rafinesque 1820) Pleurohema sinloxia (Rafmesque 1820) Quadrula eyiindrica (Say 1817) Quadnda fiai>osa (Conrad 1835) Quadrula nielanevra (Rafinesque 1820) Quadrula nodulala (Rafinesque 1820) Quadrula puslulosa ( Lea 1831) Quadrula c/uadrula (Rafinesque 1820) Tritogonia verrucosa (Rafinesque 1820) Uniomerus lelrahismus (Say 1 83 1 ) Subfamily Anodontinae Alasmidonta nuirfiinala Say 1818 Alasmidonla viridis (Rafinesque 1820) Anodonia firandis Say 1829 Anodonia imhecillis Say 1 829 Anodonta suhorhiculala Say 1 83 1 Anodonloidcs ferussucianus (Lea 1834) Arcidens confrafiosus (Say 1829) Lasmigona complanata (Barnes 1823) Lasmigona lompressa (Lea 1829) Lasmigona loslala (Rafinesque 1820) SInipsonaias anihigua (Say 1825) Slrophilus undulatus (Say 1817) Subfamily Lampsilinae Adinonaias llgamenllini (Lamarck 1819) Cyprogenia slegaria ( Rafinesque 1 820) FJIipsaria lineolala (Rafinesque 1820) Epiohlasnui flexuosa (Rafinesque 1820) Epiohlasma ohliquata (Rafinesque 1820) Epiohlasnia persona/a (Say 1829) Spectaclecase 436 Illinois Natural History Survey Bulletin Vol. 34 An. 4 Scientific Name Common Name Status' Epidhlasma pnipiinnia (Lea 1857) . Epinhlcisma rani;iiiiui (Led 1S39) Epiohlasma sumpsonii (Lea 1861 ) Epiohlasma lonilosa (Rafincsque 1820) Epiohlasma inquetni (Rafinesque 1820) Lampsilis ahrnpla (Say 1831) Lumpsilis tanliiim Rafinesque 1 820 Lampsilis fascioUi Rafinesque 1820 Lampsilis liii;i>insi (Lea 18.57) Lampsilis ovala ( Say 1817) Lampsilis sili(/ii(iick'a (Barnes 1823) Lampsilis teres (Rafinesque 1820) Leputdfa fiaplis (Rafinesque 1820) Leptndea leplodon (Rafinesque 1820) Ligumia recta (Lamarck 1819) Ligimiia suhrostrata (Say 1 83 1 ) Ohiicpiaria reflcxa Rafinesque 1 820 Ohovaria olivaria (Rafinesque 1820) Ohmaria retusa (Lamarck 1819) Ohovaria siihroluiula (Rafinesque 1820) Potamiliis alatiis (Say 1817) Potamihis capa.x (Green 1832) Potamiliis ohiensis (Rafinesque 1820) Polamilus piirpitraliis (Lamarck 1819) Ptxchohramhiis fasciolaris (Rafinesque 1 820) Toxolasma liriiliis (Rafinesque 1831 ) Toxolasma parvus (Barnes 1823) To.\olasma lexasciL\is (Lea 1857) Triiiuilla domwiformis (Lea 1828) Triiiicilla tniiicata Rafinesque 1820 Veniislacoiuha ellipsiformis (Conrad 1836) Vlllosa fahalis {Lea 1831) Villosa iris (Lea 1829) Villosa liem>sa (Conrad 1834) Order Venfroida Family Sphaeriidae (26 species) Miisculium laciistre (Miiller 1774) Muscidiiim partumeium (Say 1822) Miisculium secwis (Prime 1852) Miisculium traiisvcrsum (Say 1829) Pisidiiim adamsi Prime 1 85 1 Pisidium cascrtainim (Poli 1791) Pisidium comprcssum Prime 1852 Pisidium convcntus Clessin 1877 Pisulium crucialum Sterki 1895 Pisidium duhiiim (Say 1817) Pisidium ccpdiaterale Prime 1852 Pisidium falla.ySlerk\ 1896 Pisidium fcrrugiiicum Prime 1852 Pisidium idahociisc Roper 1 890 Pisidium lilljchorgi (Clessin 1886) Pisidium nitidum Jenyns 1832 Pisidium puiiclatum Slerki 1895 Pisidium puiiclifcrum (Guppy 1867) Pisidium rolundatuin Prime 1852 Pisidium variahilc Prime 1852 Pisidium walkeri Slerki 1895 Splhicrium faholc (Prime 1852) Tennessee riffleshell April 1991 Symposium Proceedings: Our Living Heritage 437 Scientific Name Cointnon Name Status Sphuerium occidenialc (Lewis 1856) Sphaerium rlwinhoidciim (Say 1822) Sphaerium simile (Say 1817) Splhierinni sliiiitiinini (Lamarck 1818) Family Corbiculidae ( 1 species) Corbicula fiiiininca (Miillcr 1774) Family Dreissenidae ( 1 species) Dreissena polxinorplhi (Pallas 1771) CLASS GASTROPODA (74 species) SUBCLASS PROSOBRANCHIA Order Mesogastropoda Family Valvatidae (5 species) Wihata hicaiiiMla Lea 1841 \alriila /cira/ Currier 1868 \ alvata penleprcssa Wallser 1906 \ alvata sincera Say 1 824 Valvala Iricarinala (Say 1817) Family Viviparidae (6 species) Canipclonui crassiiliim Rafiiiesque 1819 Campcloma dciisum ( Say 1817) Liopla.x suliulosa (Menke 1827) Viviparus i>eorgianiis (Lea 1834) Viyiparus iiuerlc.xtus (Say 1829) \ ivipanis siil^piiipiireiis (Say 1829) Family Bithyniidae (1 species) Billiyiua tcnhuiilala (Linnaeus 1758) Family Hydrobiidae (12 species) Amiiicolci limosa (Say 1S17) Aninivola pilsliryi Walker 1906 Amniiola ualkcri Pilsbry 1898 Birpellet sul'>glsiis (Say 1825) F(mlif>ens aldrichi (Call & Beecher 1886) Foiuifiens aiUrnecetes (Hubricht 1940) Fontifiens nickliniana (Lea 1838) H,:yici slu'ldoniiPWshry 1890) PiDlniluncUa lacuslris (Baker 1928) PyiKiiliipsis hislricu (Pilsbry 1890) Pyrgidopsis scularijonms (Wolf 1870) Somatogyriis depressus (Tryon 1862) Family Pomatiopsidae (2 species) Ponuiliopsis ciiuiiiiuitieiisis (Lea 1840) Pomatiopsis lapidaria (Say 1817) Family Pleuroceridae ( 1 1 species) Elimia coslifcra (Reeve 1861) Elimia livescens (Menke 1830) Elimia semicarinaia (Say 1829) Lcploxis pnierosa (Say 1 82 1 ) l.cpliixis triliiwiila (Say 1829) l.illhi.sia arniii;cia (Say 1821 ) Litluisia ohovala (Say 1829) Lilliasia verrucosa (Rafinesque 1820) PIviirocera acuta Rafinesque 1831 PIcurocera alvcure (Conrad 1834) PU'iiroccici <(iiicili( iiliiui (Say 1821 ) Herri ngton fingemailclam Rhomboid tlngernailclam Grooved fingemailclam Striated fingemailclam Asian clam Zebra mussel Two-ridge valvata Fringed valvata Purplecap valvata Mossy valvata Threeridge valvata Ponderous campeloma Pointed campeloma Furrowed lioplax Banded mysterysnail Rotund mysterysnail Olive mysterysnail Mud bithynia Mud amnicola Lake duskysnail Canadian duskysnail Globe siltsnail Hoosier amnicola Watercress snail Storm hydrobe Delta hydrobe Boreal marstonia Moss pyrg Sandbar pebblesnail Brown walker Slender walker Corded elimia Liver elimia Fine-ridged elimia Onyx rocksnail Broad mudalia Amiored rocksnail Shawnee rocksnail Verrucose rocksnail Sharp homsnail Rugged homsnail Siltv homsnail FC.SC PC. SO FC.SC 438 Illinois Natural History Survey Bulletin Vol. 34 An. 4 Scientific Name Common Name Status SUBCL.A.S.S PULMONATA Order BASf)MMATOPHORA Family Lymnaeidae ( 14 species) Acelhi luilJcmuni (Binney 1S67) Fossaiui chilli {Baker 1907) Fossaria Iniiiiili.s (Say 1S22) Fossarki ohnissa (Say 1823) Fossaria pan a ( Lea 1 84 1 ) Fossaria tazcwelliana (Wolf 1870) Lymnaea sia^nalis Linnaeus 1 758 Pseiiclosiiccinea columella (Say 1817) Radi.\ uiiricularia (Linnaeus 1738) Stagnicola caperaliis (Say 1829) Slaifiiicola calascopimn (Say 1817) Stagiiicola clock's (Say 1821) Slagnicoki c.xilis (Lea 1834) Stagnicoki woodriijfi (Baker 1901 ) Fattiily Physidae (3 species) AplcMi climgala ( Say 1821) Physclki gyrimHSay 1821) Physclla hclcroslriiplui ( Say 1817) Physella iitlegra (Haldeman 1841 ) Physclla virgata (Gould 1855) Family Planorbidae (12 species) Bioinphcilaria gkihrata (Say 1818) Cyraiiliis cicflccnis (Say 1824) Gyraiilus parvus (Say 1817) Helisoma ameps (Menke 1830) Micromeneiiis dilaiaius (Gould 1 84 1 ) Micromenetus sampsoni (Ancey 1885) Pkmorhclla annigcra (Say 1 82 1 ) Planorhclla cainpauiilala (Say 1821 ) Plaiiorhclla pseiictolrivolris (Baker 1920) Planorhclla trivolvis (Say 1817) Planorhclla inincaia (MWes 1861 ) Proniciictus cxacuoiis (Say 1821 ) Family Ancylidae (6 species) Fcrrissia fragilis (Tryon 1863) Ferrissia parallcki (Haldeman 1841) Fcrrissia riviilaris (Say 1 8 1 7 1 Lacvapc.x diaphaniis (Haldeman 1841 ) Laevapcx fuscus (Adams 1840) Rhodacmea hinklcvi (Walker 1908) Spindle lymnaea Dusky fossaria Marsh fossaria Golden fossaria Pygmy fossaria Tazewell fossaria Swamp lymnaea Mimic lymnaea Big-ear radix Wrinkled marshsnail Woodland pondsnail Marsh pondsnail Flat-whorled pondsnail Coldwater pondsnail Lance aplexa Tadpole physa Pewter physa Ashy physa Protean physa Bloodfluke planorb Flexed gyro Ash gyro Two-ridge rams-horn Bugle sprite Thicklip ranis-hom Bellmouth rams-hom Marsh rams-hom Druid rams-hom Sharp sprite Fragile ancylid Oblong ancylid Creeping ancylid Cymbal ancylid Dusky ancylid Knobby ancylid ' Readers may he puzzled by such dual designalions for a species as endangered and e\tirpaled or endangered and exlincl. The current Illinois list of threatened and endangered mussels was compiled in l')87. Since that time, suneys ha\e dclermlned ihal some ol the species on thai list are probably no longer extant. Future lists w ill reflect such changes and species thought to be extirpated or exiincl will be removed. At the present time, however, a species may continue lo be listed as endangered but considered by researchers to be extirpated or extinct. Streams of Illinois Lawrence M. Page, Illinois Natural History Survey The recent increased interest in protecting streams (Phillippi and Anderson 1989) is an extremely welcome development. Until now, little effort has been directed toward protecting flowing bodies of water in Illinois, largely because of the difficulties of the task. In contrast, completion of a natural areas inven- tory in Illinois and excellent efforts by the Illinois Nature Preserves Commission and The Nature Conservancy have resulted in safe- guarding a number of prairies and other terrestrial ecosystems. To protect our streams, we need to gather data and develop appropriate methodologies. To organize this process, we need to address the following questions in relation to streams: What does Illinois have? What should we protect? What are the major causes of stream degradation? How do we protect streams? WHAT DOES ILLINOIS HAVE? Because Illinois has a large and complex drainage pattern (Figure 1 ). it is considered a well-watered state, particularly in relation to most western states. It is bounded on the west by the Mississippi River, on the south by the Ohio, on the northeast by Lake Michigan, and on the southeast by the Wabash. An excellent discussion of the drainages of Illinois and their characteristics at the turn of the century was undertaken by C.W. Rolfe in Forbes and Richardson's The Fishes of Illinois 1 1908J. The biogeography of the fishes of Illinois and other states of the lower Ohio and upper Mississippi River basins is discussed by Burr and Page (19K6). The geological characteristics of Illinois strongly influence the diversity and distribu- tions of its aquatic biota, and the streams of Illinois can be classified physiographically according to Fenneman"s physiographic provinces (Fenneman 1938): I. Great Lakes: Lake Michigan Section II. Mississippi River A. Wisconsin Driftless Section B. Till Plains Section 1. Wisconsin Glacial Till 2. Illinoian Glacial Till C. Shawnee Hills-Ozark Plateaus Section D. Coastal Plain Section The streams over most of Illinois are relatively recent products of glaciation. Those flowing into Lake Michigan and those on the Till Plains Section developed after Pleistocene glaciers had receded and are less than 100,000 years old; those north of the Shelbyville moraine, the southern terminus of the Wiscon- sin glaciation, are less than 10,000 years old. In contrast, streams in the unglaciated areas of Illinois—the Wisconsin Driftless, Shawnee Hills, and Coastal Plain sections—traverse much older areas. Unglaciated areas exhibit more topographic relief and have more bed- rock; their streams are characterized by higher gradients, and they often sustain unique aquatic communities. The Illinois portion of the Wisconsin Driftless Section is found mostly in Jo Daviess County. It escaped glaciation, and the streams there are the product of millions of years of geological evolution. Relict populations of species otherwise eliminated from Illinois by the glaciers (e.g., the Ozark minnow. Notropis nuhihis) remain there. The major stream of the area is the Apple River. The Till Plains Section is the vast area of the state covered during the Pleistocene by one or more glacial advances. During glaciation, old river channels were filled with glacial drift. As the glaciers receded, drift was laid down in ridges that acted as dams holding back melt- water and creating large lakes. Later, over long periods of time, the lakes filled with deposi- tional materials, drainage outlets formed in the moraines, and the lakes transfonneil into marshes and prairies. Water flowing through 439 440 Illinois Nalurul Hislorv Sur\es Bulletin Vol. 34 An. 4 the marshes and prairies eventually cut the drainage patterns that exist today. Nearly the entire region covered by glacial till (Til! Plains Section) is drained by tributaries flowing southwest into the Mississippi River (mainly, the Rock. Illinois, Kaskaskia. and Big Muddy rivers) and by tributaries flowing southeast into the Wabash and Ohio rivers (the Vermilion. Embarras, Little Wabash, and Saline rivers). The Shawnee Hills are composed almost entirely of Mississippian limestone and sandstone and stand an average of about 400 feet above the surrounding land. Several of the most interesting streams and aquatic organisms, including species endemic to Illinois, such as the Illinois crayfish (Orconectes illinoiensis), occur in this region. The streams of the Shawnee Hills—including Big, Lusk (Figure 2), Big Grand Pierre, and Clear creeks—are small, clear rocky streams that are among the most scenic in the state. The Coastal Plain lies south of the Shawnee Hills. Flat, sandy, and covered by residual soils, it is drained almost entirely by the Cache River and small tributaries of the Ohio. Aquatic organisms found on the Illinois Coastal Plain tend to be restricted to this region in Illinois, although they are also characteristic of the Coastal Plain to the south of Illinois. Be- cause the Illinois portion of the Coastal Plain is small, many species found there are rare and restricted and therefore protected in Illinois. The present character of the streams of Illinois is as much a function of human activities as it is of the evolution of drainage patterns. What we have done to the streams in the last 200 years has had a major impact on the distributional patterns and community structure established during the millions of years of geological history that preceded our arrival. The questions now are. what does Illinois have left and what should be protected and from what? Figure 1. Major strc;iiiis of Illinois. Figure 2. Lusk Creek Canyon. Pope County, Illinois. Photo bv Michael Jclfords. April 1991 Symposium Proceedings: Our Living Heritage 441 WHAT SHOULD WE PROTECT? An element of scenic beauty apart from living organisms is certainly worth preserving, but generally we are interested in protecting life. In deciding what to protect, we can concentrate on biodiversit). The species that remain are of interest and of value to us for a number of reasons, and it seems clear that we as a society, through the establishment of environmental protection agencies and endangered species lists, have stated emphatically that we want to protect them. The reasons for protecting species include vital as well as aesthetic and economic considerations. Living organisms provide the oxygen we breathe and the food we eat and are the source of many of our medicines. We enjoy the beauty and diversity of life and acknowl- edge that our lives without wild places and wild plants and animals would be much less interesting and enjoyable. By maintaining a diversity of plants and animals, we are also maintaining a variety of choices for the biological control of noxious species: surely that option is more likely to result in a healthy environment than is resorting to potentially dangerous pesticides. Because of the enormous modifications of the Illinois landscape, we are faced with protecting large numbers of species. Our present list of endangered and threatened animals and plants includes nearly 500 species. In addition to these, which are considered to be in risk of extirpation from the state, thousands of others have disappeared or declined signifi- cantly in abundance in the past 200 years. In a sense, because Illinois is so highly modified. we are faced with protecting almost all native species. Unfortunately, it is too late to protect complete watersheds and other large areas (the exception being Heron Pond-Little Black Slough Preserve in southern Illinois), and thus we need to concentrate on identifying and protecting streams with high species diversity and those with rare species. Other parameters that might be used to select streams to protect, for example, water quality, land use. unusual habitats, naturalness of the ecosystem, and natural divisions, are reflected in the biodiver- sity. If many species or rare species are present. it is because the water quality has remained good for a long time, because unusual habitats are present, and so on. How do we recognize streams with high diversity and rare diversity? The best way is to obtain data from large geographic, in this instance statewide, data bases and compare \ arious localities with one another. Fortunately, Illinois has more complete statewide data bases on the diversity of aquatic organisms than any other state. Burr (pages 417-427. this volume) has discussed the surveys of fishes (Forbes and Richardson (1908]: Smith 1979). and Cum- mings (pages 428-438. this volume) has dis- cus.sed past (Parmalee 1967: Starrett 1971 ) and ongoing surveys of the mussels of Illinois. A third important data base is that on crustaceans, part of which was published (crayfishes and shrimps) by Page (1985). Combined, these data bases can be used to identify outstanding streams by locating those that have the highest diversity (most species) of fishes, crayfishes, and mussels, and tho.se that have the rarest diversity (i.e., those that support populations of threatened and endangered species). Outstanding streams can also be identi- fied by using the Biological Stream Characteri- zation (BSC). a stream-quality classification developed by the Illinois Department of Conservation and the Illinois Environmental Protection Agency (Hite and Bertrand 1989). The classification is based on fish community characteristics and the potential of a stream to function as a fishery resource. Stream segments are categorized from "A" (highest quality) to "E"" (lowest). Currently, 24 stream segments are considered to belong in the "A" category and about 1 84 in the "B" category. This year, the Center for Biodiversity at the Illinois Natural History Survey initiated a study to enlarge and enhance the BSC with statewide data on biodiversity. Fieldwork will update existing statewide data bases, specifi- cally those on endangered and threatened species and on the diversity of mussel species. These data, in turn, will be used to identify outstanding streams in addition to those already recognized by the BSC. The end product will be a list of streams to be protected and man- aged for their outstanding biological character- istics. Although data continue to be gathered, 20 aquatic ecosystems, including 1.^ streams, were identified as outstanding by Page, Burr, and Cummings (1989) (Table I ), and they seem certain to appear on subsequent lists of streams in Illinois most deserving of protection. 442 Illinois Nalural Histor\ Survey Bulletin Vol. 34 An. 4 WHAT ARE THE MAJOR CAUSES OF STREAM DEGRADATION? The recognition of streams worthy of protec- tion is a major accomplishment, but ultimately it becomes a meaningless exercise unless we identify the sources of degradation and initiate actions to eliminate them. Smith (1971 ) identified factors primarily responsible for the disappearance of some and the decline of other species of fishes in Illinois (Table 2). These factors negatively affect other aquatic species as well and are probably the principal threats to stream biodiversity. Because of the pervasive nature of agriculture in Illinois, siltation is undoubtedly the major cause of stream degradation and has affected at one time or another nearly every stream in the state. Silt negatively affects stream organisms in several ways and benefits only a few species that are able to tolerate the silt-laden habitats left behind when other species die out. Silt inhibits the ability of organisms to breathe by covering their gills and preventing effective oxygen exchange. High turbidity (silt suspended in water) for pro- longed periods results in the suffocation of many aquatic organisms—plants as well as animals. When the primary producers (plants) and primary consumers (e.g.. many insect larvae) are eliminated, fishes and other organ- isms dependent on them for food die or perhaps produce fewer offspring, and eventually species disappear. Silt is unsuitable as a spawning substrate for most fishes because eggs laid in silt are unable to obtain an adequate oxygen supply. Instead, fishes commonly lay their eggs on gravel or among plants, where they are hidden from predators and at the same time remain in actively flowing water and thus in a continuous supply of oxygen. In heavily silted streams where gravel and plants are covered with silt, reproductive success is reduced for many species, and they disappear after a few seasons. Mussels are especially vulnerable because of their sessile habits and. as noted by Cummings (pages 428-438. this volume), the loss of mussel diversity in Illinois has been ex- traordinarily large (2l'7f of the species have been extirpated and another 359c are in danger of extirpation.) "Drainage" as a factor contributing to the loss of fishes (Smith 197 1 ) refers to the drainage of bottomland lakes that serve many fishes as nurseries and some stream-dwelling fishes as overwintering refuges and spawning areas. In their natural condition, these lakes are extraordinarily productive (Dodge 1989) and favored areas for the grow th and development of small fishes. In Illinois, most of these lakes were found along large rivers such as the Mississippi and Illinois. Their loss resulted from drainage to produce more farmland and from filling with silt as sediment-laden rivers overtlowed during periods of flooding. It we are to protect stream organisms, the remaining bottomland lakes must be protected and. w here possible, others should be restored. .•\s more uater is consumed in Illinois, primarily for agricultural purposes, water tables Table 1. Outstanding streams of aquatic biodiversity. linois based on 1. Middle Fork Vemnilion River. Vermilion County 2. Kankakee River. Kankakee and Will counties ?. Big Creek, Hardin County 4. EiTibarras River. Jasper. CiimhorUiiiii. and Coles counties .S, North Fork Vemiilion River. Vemiilion Count) 6. Little Vemiilion River. Vennilion County 7. Crane Creek. Mason County 8. Lusk Crock. Pope County 9. Kishwaukee River, Winnebago. Boone, and MeHenry counties 10. Little Wabash River. Clay. Effingham, and Shelby counties 1 1. Mississippi River. Rock Island County 12. Wabash River. White Countv Table 2. Factors primarily responsible for the extir- pation of 8 and decimation of 60 nati\e species ot Illinois fishes. April IWl Symposium Proceedings: Our Living Heritage 443 are lowered in many places and stream desicca- tion has become a major problem. Springs that were formerly perennial are now ephemeral, and species restricted to them die during periods of drought. The disappearance of the southern redbelly dace, Pluuiiuis crylhrDgasicr, from southern Illinois is thought to be a result of the lower water table and the increased frequency with which springs dry. Detrimental interactions between exotic and native species include competition, predation, disease, and parasitism. Although some species introduced into Illinois have produced results perceived as beneficial (e.g., certain crops adopted from Europe), the vast majority have proved detrimental to native species. Familiar aquatic examples include the common carp {Cypriiuis carpio), which is notorious for its ability to stir up stream substrates and destroy otherwise suitable feeding or spawning grounds for other fishes, and the rusty crayfish {Orcimcvtes nisticns). which displaces native crayfishes in amazingly short periods of time by means that are not entirely understood. The most recent invader, the zebra mussel (Dreisscna polymorpba), is now in the Great Lakes and likely to negatively affect native mussels. It is already causing major problems in water treatment and power plants (Cummings 1990). Much has been written about stream pollution (e.g., Hynes 1960). and it is unneces- sary to detail that discussion here. Briefly, pollutants poison aquatic organisms. Major progress has been made recently in reducing point sources of pollution (Illinois Environ- mental Protection Agency 1990), but such nonpoint sources as the agricultural runoff of pesticides remain a major problem. Dams and impoundments convert large segments of flowing water into standing water. A few species are favored by the conversion, but many more are eliminated. The pre- impoundment list of species present in a medium to large river in Illinois commonly includes 30-40 species of fishes and 10-20 species of mussels. In contrast, an impound- ment typically supports only 8-12 species of fishes and 4-6 species of mussels. The nega- tive impact of an impoundment on biodiversity is compounded by the fact that species in the impoundment are always common, for ex- ample, largemouth bass (Microplcnis salmoi- dcs). gizzard shad (Dorosoma cepcdiaiuim], and common carp (Cypriiuis carpio): the species lost, however, can include threatened and endangered species. The battle in Illinois over a proposed reservoir on the Middle Fork of the Vemiilion River (Figure 3) was in part related to protection of the state-endangered bluebreast darter (Etheostama caimiriim). and the battle in Tennessee over the proposed Tellico Dam was in part related to the per- ceived threat to the federally endangered snail darter (Perciiui k/iuisi). Exacerbating the negative impact of impoundments on biodiver- sity is their tendency to fill with sediments carried by the streams flowing into them. Because they fill in, they are short-lived relative to the potential life of a stream. Figure .3. Middle Fork of the Vermilion River. Vemiilion County. Illinois. Photo hy Lawrence Page. 444 Illinois Natural History Survey Bulletin Vol. 34 An. 4 Dams negatively affect stream communi- ties in addition to the direct effects of inunda- tion. Many species of fishes migrate upstream to spawn: when a dam blocks their passage, they cannot reach suitable spawning areas. In a relatively short time, populations decline and sometimes disappear. A dam impedes and often stops the flow of water downstream and causes major alterations in the stream ecosystem. In many streams, temperature elevation results in the removal of riparian vegetation that once shaded flowing water. With direct sunlight for prolonged periods, the water is warmed and becomes unsuitable for many species. Another cau.se of wanning is the continuous lowering of the water table, with the result that less groundwater reaches surface streams. Fishes that generally prefer cool water and species adversely affected by this warming trend include trouts, nearly absent from Illinois, and sculpins, which are becoming less common and more restricted in distribution. Channelization (or canalization) of streams converts them from a series of riffles and pools of varying characteristics into a ditch of nearly uniform width, depth, velocity, and substrate. Instead of providing the variety of habitats available in an unchannelized stream. a channelized stream offers only one habitat and only those species capable of living in that habitat persist. In addition, bankside vegetation is usually removed to enable the large equip- ment needed for channelization to gain access to the stream. Loss of vegetation further reduces biodiversity. The diversity of species in a ditch is usually much lower than that in a meandering stream, HOW DO WE PROTECT STREAMS? Given the major causes of degradation (Table 2) and the multiple uses of streams in Illinois, a multifaceted approach to their protection is imperative. Our goal is to keep the native biota intact, and all approaches aimed at stream protection must have as their objective to keep the stream ecosystem as natural as possible. Broadly considered, protection means that we must prevent the hamiful de\ elopment of the stream and the watershed and the deterioration of the water quality- A third alternative, restoration (e.g., eliminating the source of a pollutant or allov\ - inu a channelized stream to return to a mean- dering stream) is a reasonable and highly desirable objective and is usually relatively inexpensive. Such massive projects as the restoration of wetlands, although desirable, can be extremely expensive and inevitably fall short of the goal of ecosystem restoration because of the intervening loss of many species previously present. Although a great deal of interest and enthusiasm is being devoted to restoration, if we must choose between protecting the remaining "'natural"" ecosystems (i.e., those least disturbed by man) and restor- ing areas, the wiser course is to protect what we have left rather than to devote limited resources to restoring abused ecosystems. Preventing development. Following the enhancement of the Biological Stream Charac- terization and the more complete listing of outstanding Illinois streams. I anticipate that the Illinois Nature Preserves Commission. The Nature Consenancy, and other conservation organizations will purchase easements, dedicate preserves, or otherwise move to protect these outstanding aquatic ecosystems. Designation of streams and key portions of watersheds (particularly headwaters) as nature preserves by the Illinois Nature Preserves Commission, the procurement of land by The Nature Conser- vancy, and similar protective measures would be major steps in keeping stream ecosystems intact because the kinds of development that negatively affect these systems would be prevented. In addition, when outstanding streams appear on an official list (in this instance, the list generated by the BSC), regulatory agencies can require that development that might negativel\ affect a stream or its watershed be undertaken in ways that minimize these effects. The identification of health) and degraded streams will result in a data base that can be extremely useful in other studies on the patterns and causes of stream degradation (e.g.. land-use studies). Protecting water quality. Water quality is protected by prexenting the introduction of contaminants such as pesticides and sewage. One extrcnicK important w ay to reduce the most detrimental nonpoint pollutant, silt, is to keep riparian \egetation intact. In central Illinois, the recent practice of plowing to the stream hank has resulted in stream bank failure and permitted large amounts of silt to enter streams. In addition to its value as a filter of April IWl Symposium Proceedings: Our Living Heritage 445 silt, riparian vegetation shades the stream from direct sunlight during the hottest part of the year, thereby benetiting the many cool-water species characteristic of Illinois streams. Legislation is needed in Illinois to reduce nonpoint pollution. Other approaches to protecting streams include the development of methods and legislation to restrict introductions of exotic species and to control the amount of water diverted from streams for municipal, industrial. and agricultural uses. SUMMARY The present characteristics and biota of the streams of Illinois are the results of geological and evolutionary history and the recent modifications of streams and watersheds by human activities. To protect Illinois streams, we need to determine what aquatic biodiversity remains, where it is located, and what compo- nents need to be protected and from what. Then we must develop the most effective means of protection. By supplementing stream quality ratings and statewide data bases on aquatic organisms with fieldwork. we can identify streams with outstanding (i.e.. high and rare) biodiversity. After outstanding streams appear on an official state list (the BSC), regulatory agencies can act to minimize environmental damage. Major threats to the integrity of Illinois streams can be identified and protective measures implemented even though streams, which are affected by activities throughout their watersheds, are clearly more difficult to protect than are many terrestrial ecosystems. Major threats to streams include siltation, drainage of bottomland lakes, desiccation, introductions of exotic species, pollution, artificial impoundments, elevated temperatures, and channelization. Protective measures include the purchase of easements and the dedication of preserves to prevent harmful development of the stream and the watershed. Water quality can be protected by preventing the introduction of detrimental substances such as silt, pesticides, and sewage. One extremely important way to reduce siltation. the most detrimental nonpoint pollutant of streams in Illinois, is to leave riparian vegetation intact. Legislation is needed in Illinois to reduce nonpoint pollution, to restrict introductions of exotic species, and to control the amount of water diverted from streams for municipal, industrial, and agricultural uses. LITERATURE CITED Burr. B.M., and L.M. Pace. 19K6. Zoogeography of fishes of the lower Ohio-upper Mississippi basin. Pages 287-324 in C.H. Hocull and E.O. Wiley, eds. The zoogeography of North American freshwater fishes. John Wiley & Sons, New York. CuMMiNGS, K.S. 1990. The zebra mussel: exotic invader. Illinois Natural History Survey Reports 298. n.p. Dodge. D.P.. ed. 19X9. Proceedings of the Interna- tional Large River Symposium (LARS). Canadian Special Publication of Fisheries and Aquatic Sciences 106. 629 p. Fenneman, N.M. 1938. Physiography of eastern United States. McGraw-Hill, New York. 714 p. Forbes. S.A.. and R.E. Richardson. [1908]. The fishes of Illinois. Illinois State Laboratory of Natural History. Danville, cxxxvi -I- 357 p. HiTE. R.L.. and B.A. Bertrand. 1989. Biological stream characterization (BSC): a biological assess- ment of the Illinois biological stream characteriza- tion work group. Special Report 13 of the Illinois State Water Plan Task Force. Illinois Environmental Protection Agency. Division of Water Pollution Control. IEPA/WPC/89-275. Springfield. IL. Hynes. H.B.N. I960. The biology of polluted waters. Liverpool University Press, England. 202 p. Illinois Environmental Protection Agency. 1990. Illinois Water Quality Report 1988-1989. Illinois Environmental Protection Agency. Division of Water Pollution Control Planning Section. lEPA/ WPC/9()-l60. Springfield. IL. Pace, L.M. 198.'^. The crayfishes and shrimps (Decapoda) of Illinois. Illinois Natural History Survey Bulletin 33(4):33.'i-448. Page, L.M.. B.M, Burr, and K.S. Cummings. 1989. Outstanding aquatic ecosystems within Illinois ba.sed on uniqueness of their fauna and envlronmenlal quality. Pages 18-20 in M.A. Phillippi and B.D. Anderson, eds. Preserving the aquatic biodiversity of Illinois: inventory, research, regulation, and protection. Proceedings of the Illinois Nature Preserves Commission 2.5th Anniversary Sympo- sium. Springfield. Parmalee. P.W. 1967. The fresh-water mussels of Illinois. Illinois State Museum Popular Science .Series VIII. Springfield. 108 p. 446 Illinois Natural History Survey Bulletin Vol. 34 An. 4 Piiiu.ippi. M.A.. AND B.D. Anderson, eds. 1989. Preserving the aquatic biodiversity of Illinois: inventory, research, regulation, and protection. Proceedings of the Illinois Nature Preserves Commission 2.5th Anniversary Symposium. Springfield. 32 p. Smith, P.W. 1971. Illinois streams: a classification based on their fishes and an analysis of factors responsible for disappearance of native species. Illinois Natural History Survey Biological Notes 76. 14 p. Smith, P.W. 1979. The fishes of Illinois. University of Illinois Press, Urbana. 3 14 p. Starrett, W.C. 1971. a survey of the mussels (Unionacea) of the Illinois River: a polluted stream. Illinois Natural Hi.story Survey Bulletin 30(.'i): 267-403. Illinois Caves: A Unique Resource James E. Gardner, Illinois Natural History Survey Unlike neighboring Missouri with over 5,000 caves, lUinois is not ivnown as a cave state. The many glacial advances that extended far south into the state buried the limestone bedrock that is so conducive to the fomiation of caves. Nevertheless, according to Oliver and Graham ( 1988), at least 480 caves are found in Illinois. They noted that the largest and most hydrologi- cally active caves occur in the Sinkhole Plain area of St. Clair and Monroe counties, one of the four major cave areas in Illinois (Figure I ). They also observed that biological activity appears greatest in caves in the Shawnee Hills Section. The study of caves (speleology) encom- passes a unique and intriguing world of darkness, one that often extends far below the earth's surface. Because caves are devoid of sunlight and green plants, they may appear foreboding to any form of life. This perception, combined with the difficult and oftentimes hazardous obstacles for intrepid scientists to overcome, would appear to make speleology an unattractive field of study. To the contrary, speleology is an exciting and rewarding pursuit. The study of cave life (biospeleology) has not been avoided simply because of potential hazards to investigators. Scientific studies of caves began as early as the 17th century in Europe, when theories on cave hydrology were introduced. Early biospeleology was limited primarily to very general faunal surveys and to descriptions of unpigmented animals (initially thought to be albino) with degenerative eye structures. In the United States, the first cave studies were spearheaded by Europeans. Constantine Rafinesque studied and named cave animals in Mammoth Cave and other caves near Lexington. Kentucky, during his visits around 1822. However, it wasn't until the late 1800s that interest in North American caves and cave life were made fully manifest. The history of biospeleology in Illinois reaches back over a century when the founder of the Illinois Natural History Survey, Stephen A. Forbes, wrote on blind cave fishes and their allies (Forbes 1881. 1882). The studies that followed much later (Layne and Thompson 1932; Gunning and Lewis 1955; Weise 1957; Smith and Welch 1978) were indirectly associated with caves and springs and focused on the spring cavefish {Clu)lo:iuster cif^assizi). By 1950, the mass of data that had been collected by nonprofessional biospeleologists, cave explorers, and surveyors encouraged more complete systematic descriptions of taxonomic groups of cave animals and their distribution. Encouraged by a rapidly growing interest in cave ecology and the physiology of cavemi- coles (animals found in caves), researchers grew more interested. Peck and Lewis ( 1977) provided the first and presently only compre- hensive information on the occurrence of more than 200 invertebrate species collected from caves in Illinois. The only other studies of invertebrate cave fauna in Illinois focused on taxonomic descriptions (Yeatman 1964; Liang 1970; Sleeves and Seidenberg 1 97 1; Lewis and Bowman 1981 ). Other Illinois studies involving caves (or abandoned mines) did not consider the larger subterranean ecosystem or its inhabitants, but focused on bats that used caves as roosts. We gained a better understanding of cave ecosystems through studies by Poulson and White (1969), Barr (1968). Caumartin ( 1963). and Poulson ( 1972). Perhaps the most compre- hensive publication concerning natural cave resources was The Life i>f the Cave by Mohr and Poulson ( 1966). Biospeleology has now become a recognized field of study. Universi- ties offer degrees with emphasis on aspects of biospeleology, and a number of nonprofit state and national cave research and conservation 447 448 lllnois Natural History Survey Bulletin Vol. 34 An. 4 organizations actively promote the study and conservation of cave resources. State and federal land tnanagement agencies have undertaken studies involving cave resources and the unique life forms associated with them(Gardner 1984. 1986: Oliver and Graham 1988; J.D. Gamer, pers. comm.). There is a great need for more informa- tion concerning Illinois caves and their associ- ated fauna. It is my intent to introduce the reader to the rich heritage of our unique cave resources in the hope of fostering appreciation and stimulating continued work. Lipman (1965) commented that "speleology has a definite place on the national conservation scene," and I share his hope that "as the need for more detailed information about under- ground conditions increases, the science of speleology will grow." Driftless Area Lincoln Hills Section Sinkhole Plain Shawnee Hills Section Figure 1. The four major cave areas of Illinois. Adapted from Oliver and Graham 1988. THE VALUE OF CAVE RESOURCES Our unique cave habitats and the diversity of life they support are subjected to environmental pressures that threaten their very existence. The delicate balance of many cave ecosystems has been needlessly destroyed by human activities. Caves, springs, and other subterranean features are a valuable part of our natural resources; yet pollution of our subterranean water systems is becoming increasingly evident, damaging the resource and in the process threatening our health and well-being. Cave explorers (sp)elun- kers) must learn to be even more conscientious in order to lessen the impact of their visits. There must be caves left in Illinois free from detrimental impacts, thereby conserving their natural state for future studies. Caves, like other more traditional natural resources, have four basic values: Intrinsic. In the most literal sense, caves are a viable and important link in the great environmental chain that binds our planet together. Caves and the resources they contain have an inherent value. Aesthetic and cultural. Caves pro\ ided dwellings for humankind long before recorded history. Often they were sacred places associ- ated with rites and ceremonies. Caves are important historically and aestheticalh . TTieir mystery exists even toda\ and the beauty of untouched cave formations (speleothems) cannot be denied. Caves are a valuable part of our heritage. Recreational. Spelunking is an increas- ingly popular recreational sport. As ca\e locations become known, explorers flock to see them. Anyone who has met the challenge of exploring passageua\ s rareK or ne\er seen will have a memorable and deeply moving experience. Caves have a recreational value but they are also an economic asset, as documented by the millions of tourists \\ ho buy tickets yearly for commercial ca\ e tours. Scientific. Perhaps the most precious value of our caves is found in the know ledge we gain from studying them. Ca\es. like pages in a history book. pro\ ide infomiation on past climate, paleontologx, and archaeolog\. Caves ha\e perhaps been studied longest by geologists, fascinated by the natural processes of caves (Bretz 1938; Harris and Allen 1952). Hydrologists and engineers have April 1991 Symposium Proceedings: Our Living Heritage 449 recognized the need to study caves and the secrets of their formation (speieogenesis). Caves provide a barometer whereby we can measure environmental quality. Dye tracing studies, with their subsequent determination of water courses, have averted serious pollution catastrophes and ensured water quality to many communities. Finally, cave environments and the animals associated with them provide living systems to study. Many cave animals have provided solutions to environmental and medical problems: others serve as examples for the study of basic ecological principles. BIOSPELEOLOGICAL OBJECTIVES Howarth (1981 ) argued that if cave inverte- brates were to be targeted for conservation, top priority should be given to conducting thorough biological inventories and ecological studies in threatened caves. He further emphasized that the long-term goal in the conservation of cave invertebrates must be the protection of suitable cave habitats. Poulson (1973) addressed cave management problems and their solutions, noting the importance of baseline biological data. Poulson and Kane (1976) provided an excellent outline for the biological inventory of caves, pointing out that most detrimental impacts could be understood only if a baseline inventory had been conducted before distur- bances occurred. The prime objectives of a biological resource inventory according to Poulson and Kane (1976) are summarized below. Identifying species. As many species of cave animals as possible should be identified and recorded from each cave under investiga- tion. This task is achieved by three methods. 1. A review of the literature. Investigators must be familiar with the work that has preceded their own if they are to conduct inventories efficiently. 2. Idenlifications in the field. Recorded observations provide a substantial amount of data with minimum impact to the cave envi- ronment. Cave invertebrates are among the most difficult hfe forms to discover, observe, and identify. Specific determinations of invertebrate cave fauna often require a taxonomic specialist. Identifications of vertebrates do not usually require detailed knowledge of microscopic taxonomic charac- teristics. Bats, salamanders, and certain fishes can be readily identified by trained observers. Collecting and preserving cave vertebrates for the sole purpose of identification is an unacceptable method of inventory. Several species of cave-dwelling vertebrates arc protected by state and federal legislation that prohibits their collection. 3. Identification through established collec- tions. Identifications of most cave inverte- brates are usually made through reference to existing collections. Specific determinations of fauna are often based on microscopic morphological characteristics (i.e., legs, antennae, mouth parts, reproductive organs). Such identifications are usually well beyond the capabilities of most investigators, and taxonomic specialists need to be consulted. Documenting cave fauna. Unfor- unately, budget constraints significantly limit the extent to which cave resources can be studied. As a result, threatened or endangered species usually receive priorities for study. This limitation should not, however, restrict the gathering of information to only those species. If an ecosystem or habitat approach is fol- lowed, all faunal elements in a cave protected for listed species can be studied. Noting species associations and ecologically related information. The identifi- cation of individual elements of a cave's fauna provides insight into the entire ecosystem. Often the occurrence of a particular species can be anticipated by the presence of another species. Identifying future study areas. Inven- tories of biological resources are important in identifying caves where more detailed studies are needed. Priorities can then be set since a detailed study of each cave is impossible in terms of time, labor, and money. Developing recommendations. Cave resources are an integral part of our natural re- sources, but responsible management or enhancement of any resource cannot be accomplished without first identifying its elements. Cave resources require very special management. THE CAVE ENVIRONMENT The cave environment affects the bcha\ior, development, and evolution of the organisms living there. The absence of light, near-constant temperatures, and the amount of humidity all 450 Hnols Natural History Survey Bulletin Vol. 34 An. 4 influence the animals found in cave.s and their positions within the cave relative to the entrance. Cave climates vary little compared to surface climates. The cave environment is cool and humidity is usually high; evaporation rates, therefore, are very low. Air currents in caves (cave breathing) are normal events in response to surface barometric pressure and can mark- edly affect temperature and humidity within a cave. Caves can be divided into zones based on the amount of light and the degree of changes in temperature and humidity. Twilight zone (cave entrance). The twilight zone extends into the cave as far as unaided human vision is possible. This zone is usually damp and cool, but temperature and humidity fluctuations are close to those found outside the cave. Some green plants may invade the entrance area, and this zone contains the largest and most diverse fauna in the cave. Animals found in the twilight zone include surface species of birds, mammals, snakes, frogs, and many different species of inverte- brates that are commonly associated with the surface. Middle zone. This zone lies just beyond the twilight zone and is characterized by total darkness. Temperature and humidity vary somewhat with seasonal changes at the surface. Animals found in this zone include bats, crickets, millipeds, and surface species of amphipods and isopods. Zone of total darkness and nearly constant temperature. This zone, like the middle zone, is devoid of light; however, temperatures fluctuate only slightly from the average annual mean temperature of the ground, approximately 13 to 15°C (54 to 58°F) in Illinois. The humidity remains nearly constant, usually near 100%. Animals inhabit- ing this zone are usually obligative cave- dwelling species such as blind, unpigmented amphipods, isopods, cave fishes, pseudo- scorpions, and springtails. THE CAVE ECOSYSTEM A cave ecosystem can be defined as all of the living organisms within a given cave bound together by interrelationships and interacting with the physical environment of the cave. Cave animals can be classified by their interaction with the cave environment or by the role they play in the cave ecosystem—their ecological classification (Barr 1963). Some organisms possess highly specialized adapta- tions that allow them to live in a world of total darkness, extremely low food availability, and relatively constant temperature. The organisms that inhabit caves are divided into two catego- ries: epigean or surface-dwelling organisms and hypogean or subsurface organisms. Epigean (surface) organisms. These animals usually must complete their entire life cycle on the surface. When found in a cave environment, they are classified as accidentals. Epigeans that wander, fall, or get washed into a cave will either escape or eventually perish there. Hypogean (subsurface) organisms. These animals normally live below the surface in caves, in subterranean water courses, or in interstitial environments (i.e.. between soil particles). The three commonly recognized classes of hypogeans are troglobites. troglo- philes. and trogloxenes. The ecological term endogean. or edaphobite. is used to classify species that nonnall\ li\e in soil (e.g.. earth- worms). Additionall). phreatobite is a term used to describe animals that inhabit the upper layers of groundwater (Holsinger 1969); it is considered synonymous with troglobite. Troglobitic species account for only 20 to 30% of the faunal assemblages of most North American caves. The largest percentages of cave fauna are troglophiles and trogloxenes. Troglobites. as the deri\ ation of their name suggests (from the Greek for hole and to live), live exclusively in caves, springs, or subterranean water systems: they cannot survive outside these environments. Troglobites are perhaps the most fascinating of all ca\e species because they possess marked morpho- logical adaptations to subterranean en\ iron- ments. Illinois contains a di\ersit\ of troglo- bitic in\ertebrates. Peck and Lewis ( 1977) reported 18 troglobitic inxertehrates from Illinois, 14 of which are considered endemic (found nowhere else on earth). However, no populations of troglobitic \ ertebrates (i.e.. true cavefishes and salamanders) are known from the state. Troglobites possess morphological, plnsiological. and behaxioral adaptations that make them unique. Compared to their surface April 1991 Symposium Proceedings: Our Living Heritage 451 relatives, troglobites have reduced metabolic rates. Tiieir sensory capabilities are modified, including reduced or absent vision, increased vibration (hearing) reception, increased olfaction (smell or chemo-reception). and increased tactile sensitivity. Their appendages are longer and more slender, and their move- ments are slov\er. more deliberate. Their bodies also tend to be more slender. Reproduction periods are acutely tuned to the seasonal availability of food, and fewer and larger eggs are generally laid. Troglophiles (cave loving) commonly inhabit caves and can complete their entire life cycle there: however, they are also found in cavelike microclimates on the surface (i.e.. deep down in surface leaf debris, in crawl spaces beneath buildings, or inside wet. rotting logs). Examples of troglophiles in Illinois are the cave salamander (Eiiryica liicifiii;a) and species of isopods and beetles. Trogloxenes (cave visitors) frequent caves for shelter and favorable microclimates but must return to the surface to complete some portion of their life cycle (i.e.. feeding and re- production). Bats are classified as trogloxenes as are raccoons, birds that nest in the entrance of caves, and certain species of snakes. THE NEED FOR CONSERVATION Bretz and Harris ( 1961 ) published descriptions and locations of more than 60 caves throughout Illinois. Their section on basic cave formation (speleogenesis) and cave types is complete and educational. Unfortunately, the publication of the exact locations of these caves opened the way for vandalizing the larger, more popular ones. Enticed by descriptions of passageways and the beautiful formations they contained, novice, adventure-seeking explorers trampled through the caves, defacing and destroying some of the finest cave resources of Illinois. Relatively few caves have been protected, and many are in dire need of protection. In response to this need, the Illinois legislature passed the Cave Protection Act in 1985. Drafted by the Illinois Department of Conservation (J. D. Garner, pers. comm.), the act established measures for the protection of the natural and cultural resources of Illinois caves. An inven- tory of the natural resources of over 80 Illinois caves was conducted by the Illinois State Museum (Oliver and Graham 1988). Addition- all), the Illinois Department of Conservation and the Illinois Natural History Survey conduct investigations of biological cave resources; emphasis is given to endangered bats. Recent protection measures for Illinois caves were perhaps precipitated by the recogni- tion (White 1973) and classification (White 1978) of these resources during the Illinois Natural Areas Inventory. As a result of that study and the ongoing efforts of the Illinois Department of Conservation, several caves have been identified as having significant natural resource features and are included in the Illinois Natural Areas Inventory. Other caves have been designated as Illinois Natural Heritage Landmarks in order to protect their valuable resources. One Illinois cave, with at least 12 miles of passageway, was purchased in 1987 and dedicated on August 31, 1989, as an Illinois Nature Preserve to protect a hibernating population of the federally endangered Indiana bat (Myotis sodalis). Another cave. Illinois Caverns, was purchased in 1986 and classified as an Illinois Natural Area. Six miles of passageway in Illinois Caverns are open to the public for exploration through a permit system designed to protect the cave. More studies are needed to identify and understand the unique biological resources of Illinois caves. The delicate and intricate natural communities of our caves cannot be protected unless we identify their elements. However, biological collections in caves should never be done without first consulting competent authorities. Over-collecting and improper collecting methods have been extremely harmful to some populations of cave species. The admonition, "Take only pictures and leave only footprints" should have special signifi- cance to every Illinoisan if we are to ensure that our unique cave resource is secured for future generations. LITERATURE CITED Barr, T.C, Jr. 196.3. Ecological classification of cavernicolcs. Cave Notes 5(2):9-12. Bakk. T.C. Jr. 1968. Cave ecology and the evolution of troglobites. Pages .3.5-102 ;/; T. Dobzhansky. M.K. Hecht, and W.C. Steere. eds. F.vohitionary Biology Vol. 2. Applclon-Ccntury Crofts. New York. 452 llinois Natural History Survey Bulletin Vol. 34 An. 4 Bretz, J.H. 1938. Caves in the Galena Formation. Journal of Geology 46:82.'S-S4 1 . Bretz, J.H., and S.E. Harris, Jr. 1961. Caves of Illinois. Illinois State Geological Survey Report of Investigations 215. 87 p. Caumartin, V. 1963. Review of the microbiology of underground environments. Bulletin of the National Speleological Society 25:1-14. Forbes, S.A. 1881. A rare fish in Illinois. American Naturalist 15(3):232-233. FORBE.S, S.A. 1882. The blind cave fishes and their allies. American Naturalist 16( 1 ):l-5. Gardner, J.E. 1984. Missouri Department of Conservation cooperative cave inventory project. Final report, Missouri Department of Conservation, Jefferson City. 125 p. Gardner, J.E. 1986. Invertebrate fauna from Missouri caves and springs. Natural History Series 3, Missouri Department of Conservation. Jefferson City. 72 p. Gunning, G.E., and W.M. Lewis. 1955. The fish population of a spring-fed swamp in the Mississippi bottoms of southern Illinois. Ecology 36(4): 552-558. Harris, S.K., Jr., and B.D. Allen. 1952. Caves of the Kincaid Limestone nearCobden, Illinois. Trans- actions of the Illinois State Academy of Science 45:196-207. HOLSINGER, J.R. 1969. Biogeography of the fresh- water amphipod crustaceans of the central and southern Appalachians. Pages 19-50 //; P. C. Holt, ed. The distributional history of the biota -of the southern Appalachians. Part 1. The invertebrates. Virginia Polytechnic Institute, Resource Division Monograph I. Howarth, E.g. 1981. The conservation of cave invertebrates. Pages 57-64 in J.E. Mylroie, ed. First International Cave Management Symposium, Pro- ceedings. Murray State University Press, Murray, KY. Layne, J.N., and D.H. Thompson. 1952. Recent collections of the amblyopsid fish Ch(>loi;cistcr papillifera in Illinois. Copeia 3:39-40. Lewis, J.J., and T.E. Bowman. 1981. The subterra- nean asellids (Caecidotea) of Illinois. (Crustacea: Isopoda: Asellidae). Smithsonian Contributions to Zoology 335. 66 p. Liang, C. 1970. The soil microfungi of Burton Cave, Adams County, Illinois. M.S. thesis. Western Illinois University, Macomb. 45 p. LiPMAN, R.P. 1965, Speleologists role in conserva- tion. Journal of Soil and Water Conservation 20:197-198. MoHR, C.E., and T.L. Pollson. 1966. The life of the cave. McGraw-Hill, New York. 232 p. Oliver, J.S., and R.W. Graham. 1988. Preliminary inventory of natural resources in select caves in Illinois. Final report. Illinois Department of Energy and Natural Resources. Illinois State Museum, Springfield. 155 p. Peck, S.B., and J.J, Lewis. 1977. Zoogeography and evolution of the subterranean invertebrate faunas of Illinois and southeastern Missouri. National Speleological Society Bulletin 40:39-63. Polilson, T.L. 1972. Bat guano ecosystems. National Speleological Society Bulletin 34:55-60. Polilson, T.L. 1975, Management of biological resources in caves. Pages 46-52 in National Cave Management Symposium Proceedings. Speleobooks, Albuquerque, NM. Poi LSON. T L., and T.C. Kane. 1976. Ecological diversity and stability: principles and management. Pages 18-21 in T. Aley and D. Rhcxies, eds. National Cave Management Symposium Proceed- ings, Speleobooks, Albuquerque, NM, Polilson, T,L., and W,B, White. 1969. The cave environment. Science 165:971-981. Smith, P.W,, and N,M, Welch. 1978. A summary of the life history and distribution of the spring cavefish. Chiilo^^asier af;as.sizi. Putnam, w ith population estimates for the species in southern Illinois. Illinois Natural History Survey Biological Notes 104, 8 p. Steeves, H.R., III, AND Seidenberg, A,J. 1971. A new species of troglobitic asellid from Illinois. American Midland Naturalist 85:231-234. Weise. J.G. 1957. The spring cave-fish. Clwlogasrer papiUiferus. in Illinois, Ecology 38:195-204. White, J. 1973. Preservation of caves in Illinois. Report for the Illinois Nature Preser\'es Commission, Rockford, IL. 1 1 p. White, J, 1978. Illinois natural areas inventory technical report. Vol. I. Survey methods and results. Illinois Natural Areas Inventor)', Urbana. IL. 426 p. Yeatman, H,C, 1964, New cavemicolous cyclopoid copepod from Tennessee and Illinois, Journal of the Tennessee .Acadenn Science 39:95-98. Session Five: Agro-Urban Ecology The lime has long since passed when a citizen can function responsibly wiihoul a broad underslandint; of the living landscape of which he is a pan.—Paul B. Sears Agricultural and urban development practices that take into account the conservation of the remarkable biodiversity of Illinois must be initiated and encouraged. A balance between economic development and the preservation of natural resources must soon be struck, for it seems that "economics" continues to win and very soon there will be little left to preserve. With the conversion of the landscape to inten- sive row cropping has come the realization that perhaps our system could operate at a somewhat less intense level. With 99.93% of the landscape of Illinois reflecting some degree of develop- ment, the point of no return seems imminent. Although the production of food is of course beneficial and necessary, the mainte- nance and restoration of our natural heritage — the landscapes that reflect presettlement conditions complete with the organisms they support—also represents a desirable and perhaps even essential course of action. Com- mon ground must be found between these two opposing courses if the requirements of both are to be met. Perhaps agro-ecology will provide that common ground. In retrospect, we seem to have been moving toward agro-ecology for some time. Consider, for example, the interest shown in organic gardening and low-input and sustainable agriculture. Agro-ecology, however, moves a step closer by requiring a balance between the requirements of agriculture and the obligation to preserve our natural heritage. While our agricultural system presently requires vast biological deserts populated by a single species, the same principles need not be applied to the surrounding landscape. Fields do not have to be cultivated to the very edges of rivers and streams; fencerows and windbreaks do not have to be removed to squeeze in a few more rows of com; railroad rights-of-way that support corridors of native vegetation do not have to be destroyed; streams do not have to be channel- ized; and species of organisms need not be driven to extinction in the name of short-lem: economic development. The next generation of agriculturalists must farm from an ecological perspective and the time has come when all lUinoisans, farmers and city-dwellers alike, must adopt a conserva- tion ethic. To quote Francis Moore Lappe, "Individual well-being is impossible outside of the well-being of others." Ultimately, we can maintain our well-being only if "others" include all species of organisms, not merely Homo sapiens. Papers read at this session introduced long-range perspectives (for example, the movement of biota between natural and managed ecosystems) as well as more immedi- ate ones (for example, the management of urban deer populations). The closing remarks, both disturbing and challenging, concluded this session and the symposium. 453 The Land Use Controversy: Maintaining and Increasing Biotic Diversity in the Agricukural Landscape of lUinois Michael E. Irwin. Illinois Natural History Survey Approximately one hundred years ago our state underwent a rapid and extensive agricultural transformation that converted the rich, fertile soils and relatively flat terrain underlying its prairies and forests into vast tracts of field crops, primarily com and soybean. With the exception of Iowa, a state with a history similar to that of Illinois, the Great Plains, with its vast expanses of wheat, and a few large tropical countries like Brazil and Indonesia, which have exploited their lands by putting in broad stretches of such perennial crops as rubber and African oil palm, there is perhaps no extensive area on earth that is so heavily cultivated in so few plant species as the state of Illinois. This agricultural transformation has taken, and continues to take, a heavy toll on native biota. With only 1 1 % of our land now left in natural vegetation and over 53% of our woody plant taxa found in cultivated areas, we have cause for concern. Can this trend be reversed? If so. at what price? Two viewpoints seem in genuine conflict. On the one hand, we have the argument that agricultural production must be sustained to meet our food needs and to offset the nation's balance of payment deficits through expanded exports. Those holding this short-term view make a powerful case that meeting these needs benefits humanity and our citizens in nutri- tional and economic ways. On the other hand, the persistent exploitation of our natural areas continues to deplete the biotic richness of our lands, diminishing the legacy for future generations and restricting our access to diverse genes for future manipulation. An equally powerful argument, this long-term perspective recognizes that what is extenninated can never be restored. I propose that these seeminglv opposing positions might be resolved in a manner that satisfies both factions. Aspects of natural systems may enhance agriculture: similarly, aspects of managed landscapes may safeguard natural systems and provide a formula for recovering biotic richness in pillaged habitats. COMPONENTS FOSTERING SYNERGISM The components that are responsible for fostering potential synergism must be deter- mined, and the interactions among those components examined. All systems could then be managed with a view towards optimizing selected synergistic interactions. Three ele- ments seem of particular importance: refugia, biological diversity, and genetic richness. Refugia. Parcels of land that for one reason or another retain unique biota during times when that biota uould othervv, ise not be present are referred to as refugia. How agricul- tural oases and other biotically favorable. artificial environments sustain species locally through times of natural emigration or diapause and how this abilit) to sustain biota affects both natural systems and managed landscapes are of considerable consequence. Irrigation in agricultural settings, particularly in semitropical areas that undergo a season of prolonged drought, can provide habitats favorable for the atypical overseason- ing of some biota. .As a result, these organisms need not emigrate or aestiv ate. Irrigation could alter the customary overseasoning habits of a variety of organisms, including insects and their natural enemies, especially in dry tropical forest habitats. Irrigation could also alter the time of \ ear during w hich certain biota in\ ade natural systems from agricultural settings, w ith a conceivably enormous impact on both s\ stems. Such in\ asions alreadv occur regu- larh in Illinois through the introduction of plants grow n in greenhouses for propagation in orchards and home gardens. 454 April 1V4I Symposium Proceedings: Our Living Herilage 455 Just as agricultural systems provide niches for noncrop-related organisms, so do natural areas harbor both pests and beneficial organisms that either plague or safeguard agricultural crops. The role of refugia in sustaining these complex interactions is relatively unknown; the repercussions, how- ever, are undeniably profound. Biological diversity. A portion of the diversity of life in one system will inevita- bly invade nearby systems; how this invasion affects a recipient system is of considerable interest to conservationists and agriculturalists alike. If agriculture is considered an invasive system that receives much of its noncrop biotic diversity in the form of colonists from sur- rounding systems, the long-term monitoring of colonization might help us to formulate models of invasion rates and types of colonists through time. Similarly, areas where agroforestry and agriculture are practiced could greatly influence the biological integrity of adjoining natural systems. Scott Robinson (page 382, this volume) provided an example at this sympo- sium when he talked about how habitat fragmentation increased nest parasitism among some of our song birds. Another example is the introduction of the honeybee, which has probably had a great, although unmeasured, impact on natural pollinators in some areas. Monitoring herbivorous insects and their natural enemies might help us develop models of biotic interchange—a third case in point. Genetic richness. Any biological species consists of a number of populations. Each population includes a number of individu- als, each with a slightly different genetic makeup or genotype. The genetic richness within a population purportedly equips that population to withstand environmental disrup- tion, although the process itself is not well understood. When a population from one system invades another, a very restricted portion of the invading population may manage to pass successfully from its resident system and colonize the other. Successful invasions of this nature are sometimes referred to as genetic bottlenecking. The result of colonization and the accompanying extinctions has enomious consequences on the sustainability of a given population, especially one in the area being invaded. The genetic richness of invading populations might well be influenced by the proximity and relative sizes and shapes of the systems in question. Such concepts as habitat fragmentation and patch dynamics are very much a part of this process. Natural systems harbor genetically adaptable populations of harmful and beneficial species that continually invade agricultural systems. Similarly, agricul- tural landscapes probably contain genetically adaptable populations that continually invade natural systems. Understanding the nature of genetic richness and how that richness affects invasion is important in designing sustainable agricultural and forestry systems. BIOTIC LINKS An inevitable exchange of biota occurs wherever two ecosystems come into contact. The zone of interchange, called an ecotone, is in a sense a battleground for genetic and biotic dominance and compatibility. When a natural system is ravaged by deforestation or by the introduction of agriculture, the system usually transforms in stages—for example, from pristine forests to high-input row-crop agricul- ture. An ecotone is established along the spatiotemporal border of this shift and could well govern the rates and types of biotic interchanges between natural and managed systems. The role of a shifting ecotone in the ecological and economic balance of biota in natural and managed systems remains a mystery and demands investigation. Refugia. biological diversity, and genetic richness are each affected by successful movement of biota across ecotones. The spatial and temporal links between natural systems and agricultural landscapes can influence the nature and. perhaps more importantly, the rate at which these interactions occur. The size and configuration of areas of land where agro- forestry and agriculture are practiced in relation to the size and configuration of the remaining natural area, for instance, could be decisive in determining how managed expanses interact with natural systems. The movement of biota between natural antl managed ecosystems can have dramatic effects on both types of systems. As stewards of this earth, we must manage the effects so 456 Illinois Nalural Hislor>' Survey Bulleiin Vol. 34 An. 4 that a balance is achieved betweeti short-term and longer-term goals. The sobering realization is that we know so little about these inter- changes and how they affect both types of systems. Our ability to sustain high-input agricul- ture has a limited horizon. Time is running out for earth's rich natural ecosystems. We must set a course that will uncover the biotic relationships between these systems so that they can be wisely managed in the future. I urge a strong, timely research and education agenda that critically addresses this issue. Farm Programs, Agricultural Technologies, and Upland Wildlife Habitat Richard E. Warner, Illinois Natural History Survey Since the late 1800s, the grassland habitat of upland wildlife in Illinois has been modified in one way or another by agriculture. Although the prairie was gone by the early 1900s. much of the farmland in Illinois through the 1950s contained various grasses, including small grains, forage crops (cool-season grasses and forage legumes), and uncultivated areas. These farmland mosaics sustained most small vertebrates that had once been common on the prairie, even though pasturing and haying caused significant mortality. After World War II. however, farm programs and agricultural technologies began to change, gradually leading to greater chemical and mechanical disturbances of farmland and the loss of grassland as row-crop farming expanded. By the late 1970s, even the most common upland wildlife—ring-necked pheasant, cottontail, bobwhite. and ground-nesting sparrows—had registered dramatic declines. During the 1980s, the intensive cultivation of com and soybeans moderated, and grassland was more widely planted, primarily as part of annual set-aside programs that diverted cropland from produc- tion. The response of upland wildlife to the reestablishment of grassland has been minimal, presumably because farm programs require or encourage management practices on set-aside fields that are not conducive to the reproduction and sunival of most small animals using grassland in Illinois. Moreover, grasslands on farm landscapes now tend to be small, linear patches unattractive to "interior" species. Such highly fragmented tracts also typically sustain high densities of opportunistic mammalian predators. Further, the intensive chemical and tillage disturbances on cropland have limited the availability of insects and plant seeds, the critical food resources of wildlife. 457 Evaluating Alternatives for Urban Deer Management James H. Witham, Illinois Natural History Survey Deer management in metropolitan areas is complicated by the conflicting values of publics with special interests. Those in charge of developing programs that address site- specific needs are well advised to consider various alternatives during the planning stage. Failure to review management options can result in uninformed or biased decisions, which in turn contribute to further controversy and reduce the credibility of those in charge of the program. Published reviews of deer manage- ment alternatives generally point out the limitations and advantages associated with various control methods and include an assessment of the usefulness of each method. Relying on such evaluations can be helpful, but making judgments too early, for example at the stage when potential options are being listed. can result in less efficient methods being censored or eliminated prematurely. Early elimination may be detrimental because less efficient methods often have desirable attrib- utes that can be combined with more efficient management techniques. Relying on a combi- nation of methods for the management of deer in urban areas is appealing because it creates a basis for compromise among diverse interest groups. In large metropolitan areas, such as Chicago, where deer are abundant and adverse interactions with people are widespread and frequent, the state wildlife agency can facilitate local decision making by maintaining a computerized data base of deer management alternatives. Three categories are useful: an unrestricted list of deer management options, potential strategies that rely on a combination of options or suggest how options can be combined, and field-tested management programs and research that document w hich methods have worked and v\hich ha\e failed and why. Such an information base is one product of the Urban Deer Study conducted by the Illinois Natural History Sur\ey. and we anticipate that it will be used by the Illinois Department of Conserv ation and the many airports, arboretums, forest preserves, and municipalities in the Chicago Metropolitan Area that manage local deer populations. 458 Illinois Railbanking Study Richard Pietruszka, Greenway Coordinator, Illinois Department of Conservation The Illinois Railbanking Study was initiated by the Illinois Depannient of Conservation in 1989 in response to the growing recognition within the state and nation that abandoned railroad corridors should be preserved for multiple public uses. Among the objectives of the study are the exploration and evaluation of the natural and outdoor recreational resources associated with the acquisition and develop- ment of greenways and their management. Detailed analyses of the following issues related to the conversion of abandoned railroad corridors into multipurpose public resources were conducted: The concerns of local governments and landowners adjacent to abandoned railroad corridors. The identification and evaluation of strategies that might allay local concerns and resolve conflict. The evaluation of the economic impact, including the impact on local taxes, of the conversion of abandoned railroad corridors to multipurpose public re- sources. The identification of the potential users of converted corridors. The principle purpose of the Illinois Railbanking Study, concluded in August of 1990. is to assist the Illinois Department of Conservation with the formulation of policies and planning strategies for a statewide trail system. 4.'i9 Closing Remarks Brian D. Anderson, Director, Illinois Nature Preserves Commission I was very pleased to be invited to offer the concluding remarks for this symposium. The Illinois Natural History Survey has developed through the years a world-renowned reputation as a center of scientific inquiry. I've found the presentations of the last two days extremely informative, but also disturbing. It is important. I believe, to look at the information provided on various species groups and community types within the context of the landscape on which they occur. Illinois has led the nation in developing institutions like the Natural History Survey, the Endangered Species Protection Board, the Nature Preserves Commission, and the Division of Natural Heritage of the Illinois Department of Conservation—all dedicated to the identification and preservation of the bio- diversity of the state. Unfortunately, the founding of these institutions w as not by coincidence. No place in the hemisphere has been more drastically altered by the hand of humankind. I might also mention that the statistics I'm about to present were also largely compiled by the Natural History Survey. Over 80% of Illinois is currently committed to agriculture, and another approximately 5*^ of its surface acreage is urbanized. That leaves approximately 15% of Illinois as undeveloped land. Of that, only 0.07 of 1 % retains to some degree its presettlement condition. The full complement of native plants and animals has been forced to survive on less than 100.000 acres of land. The impact to our biota has been devastating; of the approximately 2,500 species of vascular plants considered to be native to Illinois, 356 (about 14%) are considered to be threatened or endangered. Our vertebrate fauna has been even more severely affected; of 649 native vertebrates. 93 ( 14%) are listed as endangered or threatened, not to mention the 30 or so species that have already been extirpated from our state. And the carnage continues, but not through spectacular catastrophic events. We can't point to an Exxon Valdez or a Chernobyl. The greatest threat to the native biodiversity of Illinois isn't apocalyptic; it is simply diminu- tion, the slow but steady erosion of our biological heritage—a road here, a 404 permit there, individual by individual, population by population, species by species. I spent Earth Day in Springfield, and sprinkled among the rally speakers was the reading of a contest-w inning essay. The topic was "What Earth Day Means To Me." It caused me to reflect, and I realized I had only hopes for the meaning of Earth Day. .And foremost among these was one. I hoped that Earth Day 1990 was the last day I had to listen to the terms environmental trade-off and environ- mental compromise. We have to put a w ord back into our vocabulan,—a little uord. an important word, the word no. Where natural areas or habitats of endangered species are involved, we must "just say NO!" If it's a road. take another one. If it's a condo complex, put it somewhere else. If it's an ORV? Well, if it's an ORV. send it back to Japan. I also listened that da\ to many speeches heralding our achie\ ements since Earth Day 1970. always with special mention of passage of the Clean .Air .Act. the Clean Water Act. and the Endangered Species Act. All of these were worthy achievements. They were also all passed in \.\\e first decade after \\\c first Earth Da\. .And the reauthorization of each was challenged by the Federal Administration in the second decade after the first Earth Day Perhaps I am confused, but I thought it was prett\ ob\ ious that on Earth Da\ 1990 we were celebrating the end of a decade of en\ iron- mental backsliding. It is my hope that Earth Day 1990 was the day that 100 million citizens of the w orld let the leaders of the western world 460 April IWl Symposium Proceedings: Our Living Heritage 461 know that environmental compromise had no place on any political agenda, conservative or liberal. Planetary survival is, in and of itself, a conservative concept. A couple of years ago I sat with a conservative acquaintance listening to a presentation on the decline of the natural character of our national parks. He commented that the fellow hadn't learned that the gloom and doom message of radical environmentalism had lost its credibility. The world hadn't ended, and no one wanted to hear that message anymore. I guess he'd missed the news of Love Canal. Three-mile Island, Chernobyl, Bhopal, the donut hole in the ozone layer, and global drought perhaps due to global warming. Well, I just want to assure him that's not my message. I don't intend to sound morose: however, we have wasted a critical decade. Given our technological sophistication, we should be much farther along in solving our environmental problems, including the bio- diversity crisis. So don't worry. We no longer have time for hand wringing. I don't intend to depress you, I intend to press you; press you on every front where we possess the technology to improve the environment. So what is the job before us? First, where the preservation of significant extant resources is involved, we must be uncompromising. We can afford to lose no more. Natural areas, habitats of endangered species, and wetlands are just plain off limits from here on. The developers and planners must hear this message from scientists, conservationists, environmen- talists, and politicians. And if the latter are raising their voices in the wrong chorus, they should be sent to look for new jobs. As for specifics: We must pass legislation to extend the consultation provisions of the Illinois Endangered Species Protection Act to natural areas this session. That legislation was recently introduced as House Bill 3991. (Postscript: it never left committee.) Second, we must pass strong legislation to protect our remaining wetlands. You can help do that by supporting HB ?<1\2 and SB 1907. (Postscript: neither was brought to the lloor of the House of Representatives for a vote.) Third, we can no longer tolerate the narrow interpretation of the definition of public waters employed by the Division of Water Resources of the Illinois Department of Transportation. Governor Thompson should force the division to accept the Attorney General's opinion, which would extend the division's jurisdiction to most of our streams. If the Division of Water Resources hasn't assumed that responsibility by this lime next year, we should have those jurisdictions removed entirely from the Illinois Department of Transportation. (Postscript: a compromise measure was drafted but not introduced. ) Fourth, we should hold every one of our elected representatives responsible for seeing that the first of these three objectives is achieved. (Postscript: none was achieved.) Even if we were to lose nothing else, we probably could not ensure the long-term survival of the biodiversity of our state. We must also restore Illinois. The Illinois Nature Preserves System preserves remnants of high-quality natural communities. Most of these, however, are too small to protect wide-ranging or area-sensitive species. We must begin to establish biotic reserves, which are very large preserves having a high-quality core surrounded by degraded but restorable lands. Using the knowledge we will gain in establishing biotic reserves, we must then, through restoration management, begin to restore our open spaces to native natural communities. I had a dream a couple months ago. I dreamt I was in a village where everyone, small children to the elderly, were preparing for a wedding. Some were scouring the countryside for rocks and metals: more skilled hands were shaping gemstones and cutting jewels: still others were crafting chains of silver and gold. Finally, the bride appeared; she wasn't a young woman. She was tall—a little wide in the middle—and bore the scars of nurturing several generations of offspring. But when she was draped in that cloak of jewels and gems linked by golden and silver chains, she was trans- formed into an unparalleled beauty. I see some of those hands in our audience: I've seen them in our nature preserves: 1 have seen them building conservation areas, restoring railroad prairies, and protecting river corridors. We must do a lot more of all of these things, but we must also integrate our efforts. I would, therefore, call for the establish- ment of an Institute of Land Use Studies. The objective of this entity would be to apply the most current computer and satellite technology 462 llinois Natural History Survey Bulletin Vol. 34 An. 4 available to the identification, protection, preservation, and restoration of our native landscapes—and thereby our biodiversity. This institute would also allow Illinois to lead the nation as the center for land use planning technology. The federal government has abdicated its traditional role as a leader in this area. We should, therefore, help ourselves and at the same time develop the tools to preserve other important centers of biodiversity, for example, those in the tropics. Secondly, we should begin immediately using the Geographic Information System of the Natural History Survey to integrate state- wide natural resource planning efforts. State- wide rails-to-trails conversions, watershed planning, nature preserve and biotic reserve establishment, river corridor preservation, wetland protection, and prairie and savanna restoration should all be coordinated through a statewide protection planning committee hosted and chaired by the Department of Energy and Natural Resources. Thirdly, we should press immediately for sustained funding for natural history survey work. For far too long the Illinois Natural History Survey has been dependent on con- tracts from private, profit-motivated interests in order to monitor what is happening in Illinois landscapes. For example, although a great effort is underway to complete basic survey work on the state's streams, we are desperate for recent faunistic surveys of habitats of high endemism such as caves, seeps, and springs. We must also begin to look carefully at invertebrates, including Illinois arthropods. You will notice I didn't even mention the percentage of currently listed invertebrates. Only well-known groups of invertebrates, like mussels and crayfish, have been addressed, and we are not even sure of the total numbers of species in other groups of arthropods. A beetle found in only one cave in Illinois, one cave in the whole world, is a treasure; one that 1 am not prepared to write off. While we were all pleased that a portion of the real estate transfer tax was dedicated last legislative session to the acquisition of natural areas, there are important natural areas that will not survive the five years required for phasing in the program. We only get 20% of ,$4 million over the five-year period, 20%, 40%, 60%, 80%, and 100%, respectively. We desperately need a stopgap appropriation or bond issue of about Sl.'i million to acquire such areas before they are lost. Otherwise, as we look forward to achieving the ability to acquire outstanding natural areas, we may have to w atch some of our most important natural areas slip between our fingers. Finally, we must ensure that resources once acquired or protected are adequately managed. I propose that a dollar be added to the license fee for motor vehicles and that the proceeds be dedicated to maintenance and management of natural lands, thereby helping to compensate for the slaughter of wildlife on our highways. Now I've been told everybody and their brother has tried to get a piece of that action, but the very obvious cause-effect relationship between transportation develop- ment and loss of wildlife through habitat conversion and habitat fragmentation, not to mention direct wildlife mortality, is so obvious that I believe the public would embrace the surcharge if given the chance. Thank you for your attention. Thank you for coming, and I look forward to working with all of you in these efforts in the future. Remem- ber, we have an obligation to be objective, to treat all development interests fairly, that is. equally, but we must refrain from compromise. We've already lost too much. Appendix One: Native Illinois Species and Related Bibliography Susan L. Post. Illinois Natural History Survey The assenihlage of livingforms native to Illinois . . . are held together as a definitely organized, living whole. —Stephen A. Forbes, 1889 The Illinois State Agricultural Society was I'ormed in 1853 and brought zoologists and botanists together in an organized natural history society. In the first transactions of the Agricultural Society, three Illinois species lists were published: The Birds of Southern Illinois by H. Pratten (1853). The Mollnsca of Southern llliiuiis by H.A. Ulffers ( 1 855), and The Animals ofCook County by R. Kennicott ( 1 855). These were the first attempts to list the species of Illinois. By the turn of the century, biologists from the State Laboratory of Natural History, later to become the Illinois Natural History Survey, were systematically sampling the state. The.se early field investigations formed the basis for understanding our ecosystems and the natural histories of the organisms found in them. Because of these early records, comparisons can be made between conditions that exist today and those that existed a century ago. From its first publication in 1876, Stephen A. Forbes" List of Illinois Crustacea, to its most recent, the Survey has concerned itself not only with cataloging organisms and their distributions in the state but also with the relationships of these organisms to their environments. The Survey's long existence has allowed continuity. Field studies have been and continue to be repeated at intervals, and long-temi changes in populations and natural habitats have thereby been documented. E.O.Wilson (1988) notes in his recent discussion of biological diversity that we do not know the true number of species on Earth, possibly even to the nearest order of magnitude. The same is true for Illinois. We are fairly certain of the numbers of our more visible fauna in the Phylum Cordata—the reptiles, amphibi- ans, fishes, birds, and mammals. In other phyla, however, we are less certain. Research on many of these groups is at an early stage, and new species are frequently found. Even though we list approximately 17,000 insects, this number is only an approximation. The nematodes, which may outnumber even the insects, are an even more difficult group to estimate. The vast majority of the species in Illinois remain unmonitored. Like the dead in Gray's Elegy Written in a Country Churchyard, they may pass from the Earth unnoticed and unknown. The list of species native to Illinois that follows was not generated by a single biologi- cal survey but is the result of a search of the literature and a query of systematists fatniliar with the organisms of Illinois. Sources are listed in the bibliography and in the acknowl- edgments. The list is divided into five king- doms: Monera, Protista, Fungi, Plantae. and Animalia (Whittaker 1959). Classification of the invertebrates follows Brusca and Brusca ( 1990), and plant nomenclature follows Mohlenbrock (1986). The numbers of certain groups were impossible to estimate and are listed as unknown—the bacteria, nematodes, and protozoa. According to the Bacteriological Code ( 1958), bacteria cannot be described as simply as other organisms. Every individual is treated as belonging to a number of categories of consecutive rank. Only the individual is considered "real." Until the taxonomic prob- lems have been solved, no list of species for Illinois can be constructed. Although the protozoa are divided into seven phyla (Levine et al. 1980), we have left them as the generic "protozoa." Much of protozoan systematics is still in the alpha stage, with thousands of species yet to be discovered and classified (Lee et al. 1985). Few invertebrate groups illustrate the diversity in form, habitat, and behavior found in the nematodes. An examina- tion of virtually any organic substrate com- monly yields nematode specimens represent- ing undescribed species. The systematics of this group is in an embryonic stage. 46.^ 464 linois Natural History Survey Bulletin Vol. 34 An. 4 Although the class Insecta is very large and new species are continually being de- scribed, an estimate was made by consulting specialists for each group. The species number for Coleoptera (J. Bouseman. pers. comm.). Hymenoptera (W LaBerge. pers. comm.). and Diptera (D. Webb. pers. comm.) are only estimates. The number of Diptera was deter- mined by randomly choosing 1,000 species from A Caialoi; of the Diptera ofAmerica North of Mexico (Stone et al. 1965) and determining how many of those occur in Illinois. This process was replicated three times and a homogeneity chi square was used to de- temiine if the three samples could be lumped. A nonsignificant .v- indicated that the three samples could be combined and the mean determined. The percent of species found to occur in Illinois was multiplied by 17,000 (number of species of Diptera in North Amer- ica) to estimate the number in Illinois. Only a small fraction of the Illinois fungi are known, but estimates suggested that Illinois has at least 20.000 species (L. Crane, pers. comm.). The number of species of mites in the order Acari was estimated based on the number of mite species in Canada and the assumption that the total number of mites in Illinois would equal half the number of insect species in the state (J. Kethley, pers. comm.). In the class Aves, the number of species includes native breeding species and migrants. Determining the numbers of species that are extirpated from the state or extinct is difficult. With the exception of the showiest birds, mammals, and flowering plants, biolo- gists are reluctant to say with finality that a species has come to its end. The possibility always exists that a few individuals or a population will be discovered in some remote habitat. As with species numbers, we know with near certainty that some of the more con- spicuous fauna have been extirpated; v\e are less certain about other species. Species thought to no longer exist in Illinois are listed in Table 1 A along with the source from which the determination was made. The plant list was compiled using Sheviak ( 1978), Paulson and Schwegman (1976), Paulson et al. ( 1976), and Bowles et al. (1991), and was reviewed by M.L. Bowles, J. E. Ebinger. D.M. Ket/ner, G. Kruse. S. Lau/on, L.R. Phillippe. K.R. Robertson, J. Schwegman. M.K. Solecki, and J.B. Taft. The final list was reviewed hv K.R. Robertson. Included in Table 1 A are species listed in the 1990 Illinois Endangered Sfjecies Protec- tion Board's Checklist ofEndangered and Threatened Animals and Plants of Illinois but now considered extirpated. Not included are three species of birds, two species of mammals, and one plant species that disapp>eared from the state and were successfully reintroduced — peregrine falcon, ruffed grouse, wild turkey, white-tailed deer, beaver, and lakeside daisy. Species that no longer occur in the United States are indicated. The bibliography that concludes this appendix lists all publications that were used to create the list of native Illinois species and the table of extirpated species. ACKNOWLEDGMENTS I would like to thank the following people from the Illinois Natural History Suney: Lawrence Page and Michael Jeffords for their advice and comments. Kenneth Robertson for his help w ith the extirpated plant list. Monica Lusk for her library assistance, and Kathryn McGiffen and Kathleen Meth\ en for their help u ith the insect collection of the Sur\e\. The following p)eople gave invaluable species information: John Bouseman. J. Leland Crane. Ke\ in Cummings, George Godfrey. Jo\ce Hofmann. Wallace LaBerge. Da\ id Ketzner. Marcos Kogan. Joseph Maddox. Patti Malmborg, Philip Nixon, Loy R. Phillippe, John Taft, David Voegtiin, Donald Webb, and Mark Wetzel— all of the Illinois Natural Histor\ Sune\: Merrill Foster. Bradley Universit\ : John Ebinger. Eastern Illinois University; Helen Pigage, Elmhurst College; John Kethley. Field Museum of Natural History; Kenneth Christiansen. Grinnell College; Burt Shepard. Harza Engi- neering Company; Glen Kruse. Susan Lauzon. and John Schwegman. Illinois Department of Conservation; Mary Kay Solecki. Illinois Nature Preserx es Commission; Everett Cashatt. Illinois State Museum; Edward Mockford. Illinois State University; Bill McKnight. Indiana State Museum; Clyde Robbins. Lovola Liniversity; Martin Bowles. Morton .Arboretum: Max Hutchison. Natural Land Institute; Joseph Beait\ and George Garoian. Southern Illinois University at Carbondale; Robert .-Mien. Universit> of .Arkansas; Ellis Macleod and James Sieniburg. l'niversit\ of Illinois at Urbana-Champaign; and Michael Morris, Western Illinois Unixersitj. April I y9 1 Symposium Proceedings: Our Living Heritage 465 LIST OF NATIVE ILLINOIS TWA (AND Nl MBKRS OF SPFCIFS) Kingdom Monera (1 12' species) Division Schizophyta: bacteria (number of species unknown) Division Cyanophyta: blue-green algae ( 1 12 species) kingdum Protista ( 1.406* species) Division Proto/oa: (number of species unknown) Division Euglenophyta: euglenoids (30 species) Division Chrysophyta: diatoms and golden brown algae (440 species) Division Pyrrophyta: fire algae (20 species) Division Chlorophyta: green algae (507 species) Division Phaeophyta: brown algae (0 species) Division Rhodophyta: red algae (5 species) Division Myxomycola: plasmodial slime molds (400 species) Division Acrasiomycota: cellular slime molds (2 or 3 species) Division Plasmodiophoromycota: ( I species) Kingdom Fungi (~ 20,000 species) Division Chytridiomycota: chytrids (~ 300 species) Division Oomycota: water molds (~ 300 species) Division Zygomycota: bread molds (~ 400 species) Division Ascomycota: sac fungi (~ 9.000 species including 500 species of lichens) Division Basidiomycota: club fungi (~ 5.000 species) Division Deuteromycola; fungi imperfecti (~ 5.000 species) kingdom Plantae (2,574 species) Division Bryophyta Class Anthocerota: homworts (3 species) Class Hepaticae; liverworts (118 species) Class Musci: mosses (385 species including 2 extirpated species) Division Lycodiophyta: club mosses, quillworts, and spike mosses ( 12 species including 3 endangered species of clubmosses and 1 extirpated species of quillwort) Division Equisetophyta: horsetails ( 12 species including 3 endangered and 1 extirpated species) Division Filicophyta: ferns (75 species including 1 1 endangered. 3 threatened, and 2 extirpated species) Division Coniferophyta; conifers ( 14 species, including 4 endangered and 3 threatened species) Division Anthophyta: monocots and dicots (1.955 species including 275 endangered, 54 threatened. 53 extirpated. 1 extinct, and I extirpated but reintroduced species) Kingdom Animalia (29,662* species) Phylum Porifera: sponges ( 14 species) Phylum Cnidaria: polyps and jellyfish Class Hydrozoa: hydra and freshwater jellyfish (<10 species of hydra and I species of freshwater jellyfish) Phylum Plalyhelminthes: tlatworms (400 species) Phylum Nemertea: ribbon worms ( 1 species) Phylum Nematoda: nematodes (number of species unknown) Phylum Nematomorpha: horsehair worms (2 species) Phylum Acanihocephala: spiny-headed worms (27 species including I species found in the endangered greater prairie-chicken) Phylum Gastrotricha (60 species) Phylum Rotifera: rotifers ( 150-175 species) Phylum Entoprocta ( I species) Phylum Annelida: segmented worms Class Oligochaeta: "earthworms" (20 terrestrial and 83 aquatic species) Class Hirudinca: leeches (32 species) Class Aphanoneura (3 species) Class Branchiobdeilida: crayfish worms (9 species) 466 Illinois Nalural History Survey Bulletin Vol. 34 An. 4 Phylum Anhropoda Class Chelicerata (10,598* species) Subclass Arachnida Order Scorpiones; scorpions ( 1 species) Order Araneae: spiders (530 species) Order Pseudoscorpionida; pseudoscorpions (28 species) Order Opiliones: daddy long-legs ( 19 species) Order Acari: mites and ticks (20 species of ticks and -10.000 species of mites) Class Myriapoda (74 species) Subclass Diplopoda: millipedes (29 species) Subclass Pauropoda: pauropods (5 species) Subclass Chilopoda: centipedes (37 species) Subclass Symphyla: symphylans (3 species) Class Insecta (-17.000 species) Subclass Myrientomata Order Proturans: proturans (6 species) Subclass Oligoentomata Order Collembola: springtails (73 species) Subclass Diplurata Order Diplura: diplurans (6-10 species) Subclass Zygoentomata Order Thysanura: silverfish (6* species) Subclass Pterygota Order Ephemeroptera: mayflies { 126 species) Order Odonata: dragonflies (98 species) and damselflies (44 species) Order Blattodea: cockroaches (9 species) Order Mantodea: mantids (1 species) Order Isoptera: termites (5 species) Order Plecoptera: stonetlies (57 species) Order Orthoptera: grasshoppers, crickets, and katydids (157 species) Order Deniiaptera: earwigs (3 species) Order Phasmida: walking sticks (5 species) Order Zoraptera: zorapterans (1 species) Order Psocoptera: book and bark lice (91 species) Order Heiniptera: true bugs (910 species) Order Thysanoptera: thrips (200 species) Order Anoplura; sucking lice ( 18 native and 19 nonnative [from domestic animals and man) species) Order Mallophaga: biting lice (280 species including 1 extinct species that occurred on the passenger pigeon) Order Homoptera: plant bugs ( 1,485 species) Order Strepsiptera: twisted-wing insects ( 15-20 species) Order Coleoptera: beetles (5.000 species) Order Neuroptera: lacewings, antlions, aldertlies (45 species including 1 extirpated species) Order Hymcnoptera: bees, ants, wasps (2.000* species) Order Mecoptera: .scorpionflies (18 species) Order Siphonaptera: fleas (33 species including 1 species that occurs on the endangered Eastern wood rat) Order Diptera: true flies, mosquitoes, and gnats (4,100 species) Order Trichoptera: caddisflies ( 184 species) Order Lepidoptera: butterflies and moths (2,000 species including 1 endangered, 2 threatened, and 5 extirpated species) Subphylum Crustacea Class Branchiopoda (52 species) Order Anostraca: fairy shrimp (4 species) Order Cladocera: water fleas (-43 species) Order Conchostraca: clam shrimp (5 species) Class Maxillopoda (S4 species) Subclass Osiracoda: seed shrimp (53 species) Subclass Copcpod.i (21 species) Subclass Branchiura: fish lice (10 species) April 1991 Symposium Proceedings: Our Living Heritage 467 Class Malacoslraea (71 species) Order Decapoda: crayfish (23 species including 4 endangered and 2 extirpated species) Order Isopoda: pillbugs (28 species including 1 endangered species) Order Amphipoda: scuds ( 19 species including 5 endangered and I threatened species) Order Musida: opossum shrimp ( 1 species) Phylum Peniastomida: tongue worms (no species found in native fauna) Phylum Tardigrada: water bears ( 13 species) Phylum Mollusca Class Gastropoda: snails ( 170 species including 1 endangered species) Class Bivalvia: mussels and clams (104 species including 29 endangered. 4 threatened. 16 extirpated, and 4 extinct species) Phylum Ectoprocta (9 species) Phylum Chordata Subphylum Vertebrata Class Agnatha: lampreys and jawless fish (6 species including 1 endangered and 1 threatened species) Class Osteichthyes: boney fishes (181 species including 12 endangered. 14 threatened, and 12 extir- pated species) Class Amphibia: amphibians (39 species including 2 endangered, 1 threatened, and 1 presumed extirpated species) Class Reptilia: reptiles (59 species including 3 endangered. 4 threatened, and 1 presumed extirpated species) Class Aves: birds (297 native breeding and migrant species including 37 endangered. 6 threatened. 8 extirpated. 4 extinct, and 3 extirpated but reintroduced species) Class Mammalia: mammals (67 species including 7 endangered. 3 threatened. 9 extirpated, and 2 extirpated but reintroduced species) Total number of species: 53.754+ Total number of extirpated species : 1 1 5 Total number of threatened and endangered species: 497 Table 1 A. Native Illinois species presumed extirpated. Scientific name Common name Source Kingdom Plantae Division Bryophyta Briuhyk'ina siihiilatiiin (P. Beauvois) Schimper ex Cardot Neckc'ia peiuuila Hcdwig Division Lycodiophyta Isaacs ciiiiclmanuii A. Braun Division Equisetophyta Equisetum palustre L. Division Filicophyla Asplennim rnui-niuniriu L. Woodwardia \irgmica (L.) J.E. Smith Division Anthophyta Apiiis pikcana Robinson Arahis dnir>imii niscyi J.W, Robbins RamiiHulits amhii'ens S. Watson Rainmculus {•melinii DC. var. hiiokeh (D. Don) L. Benson Schcdimiianliis paidcidalus (Nuttall) Trelease Schemhzcriii pahisths L. var. americaiui Femald Scirpns miciocaipus Presl Scirpiis pedicc'llaliis Femald Scirpiis siihlvnuinalis Torrey Spaiaanium miiiinuim (Hartnian) Fries Thismia americaiui N.E. Pfeitfer' Traiitvetteria carollniensis (Walter) Vail Trifoliiim sloloniferiim Eaton Trillium ccrnuum L. Valerianella palcllaria (SullivantI Wood Prairie larkspur Waterwort Spike rush Horsetail spike rush Trailing arbutus Brown plume grass Umbrella grass Blanket tlower Purple avens Rattlesnake manna grass Westem cudweed Goldenpert Mare's tail St. John's wort Twinllower Adder's mouth orchid Adder's mouth orchid Mountain holly Rice grass Rice grass Bead grass Small plantain White orchis Hooker's orchid Round-leaved orchid Flowering wintergreen Pondweed Pondweed Spearwort Small yellow crowfoot Tumble grass Arrow grass Bulrush Bulrush Bulrush Least bur-reed Thismia False bugbane Running buffalo grass Nodding trillium Com salad Mohlenbrock 1981 Mohlenbrock 1978 Mohlenbrock 1976 Bowles etal. 1991 Swink & Wilhelm 1979 Mohlenbrock 1973 Bowles etal. 1991 Mohlenbrock 1986 Bowles etal. 199 Bowles etal. 1991 Bowles etal. 1991 Swink & Wilhelm 1979 Swink & Wilhelm 1979 Mohlenbrock 1978 Swink & Wilhelm 1979 Sheviak 1978 Sheviak 1978 Mohlenbrock 1978 Mohlenbrock 1972 Mohlenbrock 1972 Bowles etal. 1991 Bowles etal. 1991 Sheviak 1974 Bowles etal. 1991 Sheviak 1974 Swink & Wilhelm 1979 Mohlenbrock 1970a Bowles etal. 1991 Bowles etal. 1991 Swink & Wilhelm 1979 Mohlenbrock 1972 Bowles etal. 1991 Bowles etal. 1991 Bowles etal. 1991 Swink & Wilhelm 1979 Mohlenbrock 197()a Mohlenbrock 1983 Mohlenbrock 1981 Schwegman 1989 Bowles etal. 1991 Sheviak 1978 Kingdom Animal.ia Phylum Arthropoda Class Insecta Columhicola cMiiu Ins Malcomson Hespcna dacmac (Skinner) Notodonia simplaria Graef Pivris napi oleracca (Harris) Schinia Indiana (J.B. Smith) Speyeria diana (Cramer) Symplwrohiiis occidentalis Fitch ("lass Malacostraca Caniharus rohiisliis (iirard Macrohrachium iihionc (Smith) Chew ing louse on passenger pigeon Dakota skipper Simple promenant Mustard uhite Indiana schinia Diana fritillary Brown lacewing Lusty craytlsh 0\vo shrimp Malcomson 1937 Stemburg pers. comm. Godfrey pers. comm. lrwin& Downy 1973 Godfrey pers. comm. lrwin& Downy 1973 Macleod pers. comm. Page 198S Pase 1985 April IWI Symposium PrDccedings: Our Living Heritage 469 Scientific natiie Common name Source Phylum Mollusca Class Bivalvia Epiohlusmu flcMtiisa (Raflnesque)' EpiohUisnui ohiiqmilci (Raflnesque) Epii'hliisnui pcrsimaia ( Say ) ' Epiohlusmu propini/iiu (Lea)' Epiohlusmu rani;iunu (Lea) Epiohlusmu sampsonii (Lea)' Epiohlusmu tondosu (Raflnesque) Fiisconuiu siihroliiiulu (Lea) Hemisienu lulu (Raflnesque) Lumpsilis uhniptu ( Say ) Lc'piock'u Icpiodon (Raflnesque) Ohovuriu iTtiisu (Lamarck) Plelhohusus cicatricosus (Say) Pleiirohemu plenum (Lea) Qiiuihiilafragosa (Conrad) \ 'illosu fuhulis (Lea ) Phylum Cordata Class Osteichthyes Alraclosleiis sputiilu (Lacepede) Coret^oniis nigripinnis (Gill) Ciysialluiiu asprellu (Jordan) Esox musquinoniiy Mllchlll Elheoslomu hislrio Jordan & Gilbert Hyhopsis umhiops (Raflnesque) hhihyomxzon hdelliuni (Jordan) Lylhninis uicleiis (Cope) Noliirus stij>mosiis Taylor Percina evides (Jordan & Copeland) Percina uranidea (Jordan & Gilbert) Pleionotropis hiihhsi (Bailey & Robison) Class Atnphibla Crypiohiuiicliiis ulU\i;uiiiciisis (Daudln) Class Reptilia Nerodiafasciulu ( Linnaeus ) Class Aves Ajaiu ujaju (Linnaeus) Cumpcphihis prim ipulis (Linnaeus)' Comiropsis curoliiiciisis (Linnaeus)' Conns coni.x Linnaeus Cyf;mis hiiccinulor Richardson Eclopistes mifii'uloriiis (Linnaeus)' Numenius horealis (Forster)' TympaniK hiis phusiunelliis ( Linnaeus) Class Mammalia Bison hison (Linnaeus) Cunis lupus Linnaeus Ccrviis cluplnis Linnaeus Eielhizon dorsaliim (Linnaeus) Eelis concolor Linnaeus Murles americanu (Turton) Murlcs pcnnanii ( Erxleben ) Pennnysciis i;ossypimis (Le Conle) Ursiis amviicuniis Pal his Leafshell 470 illmiiis Nalural Historv' Survey Bulletin Vol. 34 An. 4 BIBLIOGRAPHY: NATIVP: ILLINOIS SPECIES Bacteriological Code. 1958. 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Alexander 476 Coffee break allowed time for speaker Joyce Hofniann to continue her advocacy on behalf of those troubled wetland tenants, the swamp rabbit and rice rat. Brooks Burr's concern over threatened fish and dw indling aquatic habitat answered Thoreau's query. ""Who hears the fishes when they cry?" We do. Louis Iverson's use of satellite data piqued interest in INHS Special Publication I I: Forest Resources of Illinois with its 67 computer-generated maps. James "'Gene" Gardner's research on caves mtro- duced us to the fragility and fa.scination of that dark and silent habitat. Survey support staff set up exhibits for the symposium and rolled posters for mailing. In an economy drive, staff collected the ^5^) paper towel tubes used to mail the posters! 477 Illinois Natural History Survey 607 East Peabody Drive, Champaign, Illinois 61820 A Division of the Illinois Department of Energy and Natural Resources