SEASONAL ABUNDANCE AND HABITAT USE OF SELECTED SNAKES TRAPPED IN XERIC AND MESIC COMMUNITIES OF NORTH-CENTRAL FLORIDA C. Kenneth Dodd, Jr.,1 and Richard Franz2 ABSTRACT We studied the upland snake community on the Katharine Ordway Preserve-Swisher Memorial Sanctuary during the years 1989 and 1990. A total of 220 wire-mesh funnel traps were deployed at seven xeric and three mesic habitats for a total of 39,162 trap nights. Habitats were sampled from March or April to September or November, depending on year and location. Fourteen species (276 individuals plus 53 recaptures) of snakes were captured, nearly all in traps, of which the five most abundant were Cemophora coccinea, Coluber constrictor, Masticophis flagellum, Micrurus fulvius, and Sistrums miliarius. The high-pine snake-community was slightly more diverse and evenly distributed than that of the other xeric or mesic habitats. Snakes were active throughout the sampling period but showed complex rather than strictly modal patterns of activity. In general, there appears to be little seasonal or macro-level habitat partitioning among the five most commonly trapped snakes. Neither monthly rainfall nor temperature appeared to influence capture. The black racer (Coluber constrictor) was the most commonly trapped species in all habitat types, with larger racers caught in more structurally diverse habitats. Sampling biases may account for the lack of capture of certain species or the underrepresentation of species known to be more common than capture data indicate. Funnel traps should be used in conjunction with other techniques to remove sampling biases when inventorying and monitoring snake communities. RESUMEN Estudiamos la comunidad de culebras, habitante de las tierras altas en la Katharine Ordway Preserve- Swisher Memorial Sanctuary, durante 1989 y 1990. Se insta16 un total de 220 trampas de alambre 1 The senior author is a Research Zoologist, National Biological Service. Biological Science Center, 7920 NW 71 st Street, Gainesville FL 32653, U.SA, and and Courtesy Cuiator of Herpetology, Florida Museum of Natuial History, Univeysity of Florida, P. O. Box 117800, Gainesville FL 32611-7800. U.SA 2 The junior author is an Associate in Ecology, FloTida Museum of Natural History. University of Florida, P. 0. Box 117800, Gainesvine FI 32611-7800, U.SA DODD, C. K., JR., and R. FRANZ. 1995. Seasonal abundance and habitat use of selected snakes trapped in xeric and mesic communities ofnorth-central Florida. Bull. Florida Mus. NaL Hist 38, Pt 1(2):43-67. 44 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 38 PT. I(2) tubulares en siete habitats x6ricos y tres habitats mdsicos, por un total de 39.162 trampas-noche. Bs habitats fueron muestrados de marzo o abril, a septiembre o noviembre, dependiendo del aao y la localidad Se capturaron 14 especies (276 individuos. ademas de 53 recapturas) casi todas et trampas, siendo las cinco especies m*s abundantes Cemophora coccinea, Coluber constrictor, Masticophis flagellum, Micrurus jidvius y Sistrums milian'uj. La comunidad de culebras de sitios altos con ping fue levemente mAs diversa y mds homogdieamente distribuida que las comunidades de otros habitats x6ricos o mdsicos. Las culebras cstuvieron activas a lo largo del periodo de muestreo, aunque mostraron patrones de actividad mds complejos que estrictamente modales. En general, parece haber poca partici6n de habitat estacional o a un nivel macro, entre las cinco culebras mas comunmente capturadas. Las capturas no parecieron estar influenciadas por pluviosidad mensual ni temperatura. La corredora negra (Coluber constrictor) fue la especie mas comunmente atrapada en todos los tipos de habitats siendo las corredoras nids grandes capturadas en habitats inds estructuralmente diversos. La ausencia de captura de algunas especies o la subrepresentaci6n de otras especies conocidas como mAs comunes que 11 que indican los datos de captura, puede deberse a sesgos de muestreo. Las trampas tubulares debieran ser usadas en conjunto con otras ttcnicas con el objeto de remover sesgos de muestreo cuando se inventorean y monitorean comunidades de culebras. INTRODUCTION Relatively few studies have focused on snake community ecology, especially because of sampling difficulties (Vitt 1987). In order to fully appreciate the importance of snakes in community organization, however, species richness, abundance, and annual and seasonal variation in activity patterns must be determined. Sampling a variety of habitats using standardized techniques helps record variation in habitat use that is then subject to investigation using experimental procedures. At one time, the longleaf pine (Pinus palustris)-turkey oak (Quercus laevis)- wiregrass (Aristida stricta) community stretched along the Atlantic and Gulf coastal plain from Virginia south to Florida including a major portion of the Florida peninsula (Myers 1990), and westward to Texas. The community comprised approximately 28.3 million hectares, of which less than 10 percent remains (Croker 1979; Means and Grow 1985; Noss 1989). Interspersed within the longleaf pine forests are other communities, such as hardwood and swamp forests and xeric and mesic hammocks (Myers and Ewel 1990), which developed in response to local soil, fire, and hydrological conditions or resulted from past anthropogenic causes. All these communities are collectively termed uplands. Many species of vertebrate and invertebrate animals occur in these botanically rich communities. Little is known, however, concerning the life history and habitat use of most of the snakes that reside within upland communities. The Katharine Ordway Preserve-Swisher Memorial Sanctuary includes a variety of upland habitats. From 1983 through 1988, RF conducted a general inventory of resident vertebrates, including snakes. From 1985 through 1990, CKD monitored the herpetofaunal community inhabiting a temporary pond located between a longleaf pine and xeric oak hammock (Dodd 1992). As a result of our efforts, 23 snake species now are known from the Ordway Preserve (Franz this vol.). The present study was undertaken to provide a more systematic inventory of the snakes inhabiting upland communities on the Ordway Preserve, and to examine DODD & FRANZ: UPLAND SNAKES 45 factors that might influence sampling results. Throughout this paper, we use the term community as defined by Begon et al. (1986), i.e. "an assemblage of species populations which occur together in space and time." ACKNOWLEDGMENTS We thank Bert CharesL Shelley Franz. and Lora Smith for checking traps, handling snakes, recording dala. and general dedication to the project Robert Reynolds Gordon Rodda, and Norm Scott provided helpful comments on the manuscript STUDY AREA The Katharine Ordway Preserve-Swisher Memorial Sanctuary (hereinafter referred to as the Ordway Preserve) is a 3750 ha tract located approximately 5 km SE of Melrose, Putnam County, Florida. This upland sandhill region lies within the Interlachen Karstic Highland at the southern flank of Trail Ridge. The area represents a portion of a dune complex that probably formed in association with active beach development during periods of higher sea levels. The dunes have been secondarily modified by solutioning activities in the underlying limestones to form sinkholes and karst basins. Many of these solution features hold water to form the ponds, lakes, and wetlands of the Ordway Preserve. Two types of aquatic systems occur on the Ordway Preserve, a series of isolated clear water ponds and lakes and Mill Creek. Mill Creek is an extensive creek system that drains the eastern parts of Trail Ridge and the Interlachen Karstic Highlands. It flows through Etonia and Rice creeks into the St. Johns River. On the Ordway Preserve, the basin includes an extensive swamp forest, eight tannin-stained lakes, and four freshwater marshes. Franz and Hall (1991) provided a detailed discussion of the physical setting of the Ordway Preserve. HABITATS General information and references on Florida communities are in Myers and Ewel (1990). Franz and Hall (1991) identified eight vegetative communities on the Ordway Preserve, five of which were sampled during this study. Approximately 66% of the property is composed of upland and ruderal vegetation types, while the rest consists of open water pond and lakes or wetlands. More than 70 water bodies existed on the property prior to a severe drought that began in 1985. This number was reduced to seven at the height of the drought in 1990. 46 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 38 PT. 1(2) Most communities have been influenced by human disturbance and past fire histories. Between 15% and 25% of the property is believed to have been cleared for agriculture and human habitation since 1850. Several of these areas have regrown through old field succession to xeric sand live oak and mesic hardwood hammocks. Regular prescribed burning of high pine forests was established in 1983 as a part of the Ordway Preserve's management protocol for the purpose of reestablishing the native longleaf pine ecosystem and reducing fuel loads. High Pine Forest.-- Also known as sandhill, this community type is dominated by longleaf pine (P. palustris), turkey oak (Q. laevis), and wiregrass 04. stricta). High pine requires frequent fires in order to maintain its open aspect, to sponsor pine and wiregrass regeneration, and to control invasive weed species. Located on Candler and Apopka soil types, the community occurs on deep sands associated with dune ridges. Sand Live Oak Hammock.- This community naturally occurs as fringes around certain wetland types. It also occurs on ruderal sites. Dominated by sand live oak (Q. geminato) and occasionally by laurel oak (Q. hemisphaerica), sand live oak hammocks can have dense understories composed of sapling oaks, blueberries (Faccinium spp.), myrtle oak (Q. myrtgolia), and other woody plants. Reindeer lichens (Cladonia spp. and Cladina spp.) and herbaceous species are more prevalent in open hammocks. Prescribed fires rarely idtrude into sand live oak hammocks because of sparse fuels and higher moisture conditions than adjacent high pine forest. For purposes of this paper, sand live oak hammocks are termed open (vel little understory) or closed (very dense understory with complex habitat structure) xeric hammocks. Mesic Hardwood Hammocks.-- Located on the lower slopes of the Mill Creek valley, most mesic hardwood hammocks are dominated by mesic species, particularly sweet gum (Liquidamber styracvlua), pignut hickory (Carya glabra), wild olive (Osmanthus americanus), water oaks (Q. nigra), and southern magnolia (Magnolia grandiflora), although more xeric-adapted pines and oaks commonly occur on some sites. The interior of most mesic hammocks tend to remain open, except where saw palmettos (Serenoa repens) form dense thickets. Fires rarely burn into this community, although they historically have invaded the upper Mill Creek valley as evidenced by fire-scarred slash pines (P. elhotti) in the vicinity of Mill Creek ford. Swamp Forest.-- Dominated by red maple (Acer rubrum), sweet bay (Magnolia virginiana), black gum (Xyssa sylvatica), and dahoon holly (Ilex cassine), this community type is restricted to the Mill Creek valley bottomland. In some areas, slash pines and pond cypress (Taxodium ascendens) form important DODD & FRANZ: UPLAND SNAKES 47 components. Ericaceous shrubs often are common understory species. Ferns and sphagnum moss can form an extensive ground cover on wetter sites. Freshwater Marshes.- Extensive wet prairies occur in four large solution depressions associated with the Mill Creek basin. Certain of these marshes are dominated by semi-woody species, such as swamp loosestrife (Decodon verticillatus), fetterbushes (Lyonia lucie/a), Virginia willow Utea virginica), and buttonwood (Cephalanthus occidentalis), while others are composed of maidencane (Panicum hemitomon) and various sedges. Both types of marshes frequently have small to large localized stands of sawgrass (Cladium jamaicense) associated with depressions in the peat. Fires probably have played important roles in these marsh systems in the past, which probably helped to control invasive woody species. Currently, Ordway Preserve managers are not burning these sites. METHODS Xeric Community Sampling In 1989, 100 individually numbered screen wire mesh double-opening funnel traps (90 cm long by 18-25 cm diameter; see Fitch 1987) were placed at six upland sites as follows: 31 traps in closed xeric (sand live oak) hammock (11 at the Fennell homestead [Ordway Preserve site location 121; 20 south of Enslow Lake [Ordway Preserve site location 21]); 59 traps in sandhill (high pine) habitat (9 at the Fennell homestead; 10 in the vicinity of Polecat Flats [Ordway Preserve site location 191; 10 in the vicinity of Dry Pond [Ordway Preserve site location 201; 30 in the vicinity of Single Shot Pond [Ordway Preserve site location 231); 10 traps in open xeric (sand live oak) hammock (all in the vicinity of the McCloud homestead [Ordway Preserve site location 22]). The locations of the sampling areas are shown in Figure 1. In most cases, the traps were set along fallen trees and branches that formed natural drift fences. At locations 19 and 20, traps were set along drift fences made of 10 m sections of galvanized metal set in 4-pronged arrays (Campbell and Christman 1982, fig. 1). The traps were covered with palmetto fronds to prevent captured animals from overheating in the direct sun and to provide cover. The traps were checked daily from April 4 through November 17 (23,800 trap nights) between 0700 and 1200 h. Trapped snakes were returned to the laboratory. Prior to measurement, they were cooled for 1-4 h depending on size. The following data were recorded: snout- vent and tail length (in mm using a ruler), wet mass body weight (in g using a Pesola spring scale), sex (using standard reptile sex probes to determine the 48 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL 38 PT. I(2) : 5#46 POTNAM PRAIRIE TWOMILE L.< ~ ~Y/f-kK~i~fil _LL«HARRY tIf.y: ·· \ 6 -0 PRAIRIE_'* .- "-I . V- 32 ~MANDARINE /ROSA J BLUE P. ..- 2... I 6'SHADY TWOMILE P. C / AS 0.05), average monthly temperature (r. = 0.248, p > 0.05), maximum monthly temperature (r. = 0.431, p > 0.05), or minimum monthly temperature (r, = 0.219, p > 0.05). DISCUSSION Species Richness and General Habitat Use.- The xeric and mesic habitats on the Ordway Preserve appear to have similar snake species richness, at least on a macrohabitat level. Sampling was conducted on a relatively coarse scale, i.e. no trapping was undertaken in specialized habitats such as fossorial or arboreal locations within the xeric and mesic habitats. No new records were obtained for the Preserve, and our subjective impressions of the relative abundance of some species were substantiated. The Ordway Preserve has similar species richness with DODD & FRANZ: UPLAND SNAKES 59 5 - 4 1989 N = 11 1990 N = 42 3 N U M BE R C AP TU R ED 2 :-11-- 1 301 320 340 486 557 611 801 823 941 TRAP NUMBER Figure 8. Total number ofsnakes captured by individual traps in mesic habitats, 1989-1990. The dark bars at the top ofthe graph show which traps were open in 1989 (top) and 1990 (bottom). N refers to the total number of snakes captured. 8 7 6 5 NU M BE R O F IN TE RV AL S 4 3 2- 1 0 50 100 150 200 250 MEAN NUMBER OF DAYS BETWEEN RECAPTURE Figure 9. The relationship between the number of intervals between snake captures at a trap and the mean number of days between capture. 60 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 38 PT. I(2) 20 S ~ 16 0 - Z . * b.*2 ** 35 ).. 2 1 O *S ]#%~~ ,%* 1 JU 1 -1 1 n - * * 8 . FE=10· 0 1 23458789 SNAKES PER FUNNEL 12 10 NU MB ER O F FU NN EL S NU M BE R OF F UN NE LS 8 6 4 *5 bli ,-9 dm#,1'mmm O ':'f I *':*j~ 1)):§}j='.1 1.%{Sl 0 1 23456789 SNAKES PER FUNNEL 4 3 CE~-·r 72 '.= IF*,m~~~~ , ~ »,{St* ]~R 1*:#0 #'~041 /,/ ''I:" SER> Pids{~] E -j E.r·:88:*81 01 23456789 SNAKES PER FUNNEL Figure 10. The relationship between the number oflraps and the,total number of snakes captured per trap in different xeric habitats in 1989. (A) Sandhills; (B) Closed xeric hammock; (C) Open xeric hammock DODD & FRANZ: UPI.AND SNAKES 61 40 A B30 N U M BE R O F FU N N EL S N U M BE R O F FU N N EL S 20 CD 10 all *fl n St _ m,/«.,-/, 012 0 1 0 1 01234 SNAKES PER FUNNEL Figure 11. The relationship between the number of traps and the total number of snakes captured per trap in different xeric habitats in 1990. (A) Sandhills; (B) Closed xeric hammock; (C) Open xeric hammock; (D). Sample site surrounding Breezeway Pond. 80 ~1989 ~ 1990 60 4OA B C 20 0 1 01 0 234 SNAKES PER FUNNEL Figure 12. The relationship between the number oftraps and the total number of snakes captured per trap in different mesic habitats in 1989 and 1990. (A) Prairie; (B) Swamp Forest; (C) Mesic hammock. 62 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 38 PT. I(2) Apr 89- May 89 - .:::::::6 Jun 89-~ Ju189-~ Aug 89-~ Sep 89 - ~ Oct 89 - ~ Nov 89 - I..../........MMM Mar 90 - ~ Apr 90- -./........ May 90 - Ii./.Il./.././IN Jun 90 - ~' Ju!90-~ Aug 90 -~ Sep 90- I~ i,1 :1 30 25 20 15 10 5 0 5 10 15 20 25 30 Temperature (C) Rainfall (cm) Figure 13. Average monthly temperature and total rainfall amounts on the Katharine Ordway Preserve- Swisher Memorial Sanctuary during the 1989 and 1990 sampling period. comparable sized habitats at the same latitude (Vitt 1987). However, sampling in other habitat types, particularly the wetlands, may increase the number of species known to occur on the Preserve. The black racer was trapped in substantial numbers in all habitat types. Relatively more black racers were found in mesic hammocks than in xeric habitats, especially considering differences in sampling effort, but whether this reflects habitat selection by different size classes or a response to different prey abundance (Toft 1985; Vitt 1987) is unknown. In xeric habitats, racers were nearly equally abundant in both high pine and in closed xeric hammock. In all habitats, capture frequency was proportional to sampling effort. The ubiquitous distribution and general abundance of Coluber suggests that it is an upland habitat generalist. The next four most commonly trapped species (Cemophora coccinea, Masticophis flagellum, Micrurus fulvius, Sistrurus miliarius) were found bolli in xeric and mesic habitats, but the numbers trapped seemed to indicate a preference for the dryer habitats. A narrowing in habitat preference from that shown by C constrictor is reflected by the lower niche breadth values for these species. With the exception of S miliarius, considerable niche overlap occurs. In upland habitats, the pygmy rattlesnake was the most xerophilic of the common snakes trapped DODD & FRANZ: UPLAND SNAKES 63 during this study although in other areas they are common in wetlands (e.g. Hudnall 1979). The rest of the snakes trapped during the study were caught infrequently. Based on other observations (see below), several of them (e.g. Crotalus adamanteus, Pituophis melanoleucus) are known to be common on the Ordway Preserve (Timmerman 1989; CKD and RF unpubl. data). Others are wetland- associated species. Only Heterodon platyrhinos appears to be rare on the Ordway Preserve and was trapped infrequently. Additional sampling, using a variety of techniques in more habitat types, will be necessary before the habitat associations of these species on the Ordway P.reserve can be discerned. We suggest that a possible explanation of the similarity of the upland snake faunas in different habitat types on the Ordway Preserve is that they share a similar derivation. Approximately 47 percent of the uplands presently are in high pine vegetation. Xeric hammocks are found surrounding the numerous lakes in formerly cultivated areas on the property and in the Mill Creek valley. Examination of aerial photographs taken more than 30 years ago and conversations with elderly residents familiar with the land confirm that most xeric hammocks were cleared for agriculture or homesteads at one time, usually 50 to 70 years ago. These hammocks probably were in high pine vegetation prior to cultivation. Thus, the xeric hammocks are of relatively recent origin and do not contain species, such as Storeria occipitomaculata, found in historically undisturbed hammocks. Seasonal Activity Patterns.- The five most commonly trapped species did not show similar seasonal activity patterns, and the activity patterns (Fig. 4) often were different from literature records. For example, Coluber constrictor is reported to have a bimodal seasonal activity period in Nebraska based on road kills (Oliver 1955), and a unimodal activity period centered on, the late spring to early summer in South Carolina (Gibbons and Semlitsch 1987) and southern Florida (Dalrymple et al. 199lb). Micrurus is active year-round in Florida with a bimodal activity season in spring and autumn (Jackson and Franz 1981; Dalrymple et al. 199lb). Our observations are similar to literature records for Sistrurus (Hudnall 1979; Dalrymple et al . 1991b), Masticophis (Ford et al . 1991 ), and Cemophora (Reynolds 1980; Gibbons and Semlitsch 1987; Dalrymple et al. 1991b). The four most trapped species were active throughout the sampling period, as reflected in niche breadth values. Micrurus overlapped seasonally least with the other species, whereas the warm weather xeric habitat species Cemophora, Masticophis, and Sistrurus had the greatest seasonal niche overlap. The spring activity peak in Coluber and the autumn increase in Sistrurus are reflected in their medial niche overlap values. In general, there does not appear to be much seasonal partitioning of activity, perhaps because of the generally long activity seasons of most species. Gibbons and Semlitsch (1987) suggested that Temperate Zone snakes showed two general activity patterns, a unimodal pattern centered on warm weather 64 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 38 PT. 1(2) activity and a bimodal pattern centered on spring and autumn activity peaks. On the Ordway Preserve, such patterns were observed, but the patterns were more complex with less adherence to a particular modality. Failure to conform to recognized patterns suggests that sampling may be biased, that 1989 may have been an unusual year in terms of snake activity, that concepts of modality in subtropical snake activity patterns need to be refined to incorporate the possibility of both variation and complex patterns, or that all of these factors may be true. In areas with year-round activity, snakes seem to keep the general patterns observed in more northern latitude relatives but retain the plasticity to modify activity in accordance with local environmental conditions (Dalrymple et al. 1991b). Sampling considerations.-Funnel traps have been used successfully to obtain data on both individual snake species and communities (Fitch 1960 1987; Ford et al. 1991). Clearly, the technique is effective at capturing certain upland species, such as Coluber, Micrurus, and Sistrurus. Six or more snakes were captured in only five traps throughout the study, providing little evidence of biased trapping. Although more traps had zero capture success in xeric habitats in 1990 than in 1989, the sampling effort was only 16% of that in 1989. Likewise, many mesic habitat traps had zero capture success during the two-year study, but mesic habitats were sampled for only 28% of the sampling total. Snakes did not shy away from any cluster of traps in any habitat type. On the other hand, why did most traps capture few snakes? Several hypotheses are possible, including insufficient sampling effort, generally poor trap placement, low snake density, or escape from traps before the observer checked them. Snakes also may avoid traps in which other snakes had been caught, perhaps due to chemoreceptive cues left by previous occupants (but see Weldon et al. 1990). None of these hypotheses can be ruled out, and all may affect capture success. The 14 species of snakes trapped during the study represent 61 percent of the snakes known from the Ordway Preserve (Franz this vol.). Other snake species (Diadophis punctatus, Drymarchon corals, and Tantilia relicta) are known from upland habitats on the Ordway Preserve but were not trapped. In addition, general collecting, radio-telemetry studies, and subjective impressions suggest that additional species, such as Crotalus adomanteus (Timmerman 1989), Elaphe guttata, E. obsoleta, and Pituophis melanoleucus, were underrepresented in funnel traps in relation to their probable abundance. Such discrepancies suggest that funnel trapping alone is inadequate to sample all species of an upland snake community. Snake size, habitat specificity, and foraging mode may play an important role in the effectiveness of funnel traps to sample communities. Those upland species either not trapped or underrepresented were generally small as adults (Diadophis, Tantilla) or very large and robust as adults (Crotalus, Drymarchon, Pituophis). On the other hand, small robust Sistrurus and large slender Masticophis were trapped. Habitat specificity, such as fossorial (Tantilla) or arboreal (E guttata, Opheodgs) DODD & FRANZ: UPLAND SNAKES 65 habitat preferences, may restrict the effectiveness of funnel trap sampling. Ford et al. (1991) also were unable to capture Tantilla in funnel traps. Several species that were trapped, such as Nerodia faciata and N tarispilota, are aquatic species and as such were unexpected in xeric upland habitats. However, Dodd (1992) found some non-resident aquatic or wetland- associated species that regularly visited a small isolated temporary pond located in upland habitat on the Ordway Preserve. Snakes normally associated with wetland habitats may travel across unfavorable habitat to find foraging areas or to disperse during unfavorable environmental conditions (Dodd 1993; Seigel et al. ms). On the Ordway Preserve, six additional wetland-associated species (Farancia abacura, Nerodia jloridana, Opheodrys aestivus, Regina alleni, Seminatrix pygaea, Thamnophis sauritus) are known to at least occasionally cross upland habitat (Dodd 1992; unpubl. observ.) but were not trapped during the study. The likelihood of trapping wetland-associated species as they move across upland habitat would seem to be small, unless the uplands were located adjacent to wetlands subject to periodic desiccation. In such locations, seasonal snake activity is influenced by fluctuations in the water table resulting in increased capture as wetlands dry (Bernardino and Dalrymple 1992). Finally, active foragers, such as Masticophis and Coluber, should be more likely to encounter funnel traps than sit-and-wait predators such as Crotalus. Active foragers, especially those that take a wide range ofprey, also are more likely than sit-and-wait predators to be drawn to traps through intra- or interspecific chemical cues or the activity of prey species (lizards, other snakes, or rodents) caught in the traps. Based on our results and those of other recent investigators (Fitch 1992; Grant et al. 1992; Rodda and Fritts 1992), we suggest that funnel traps should not be employed as the sole method for community sampling. All sampling techniques have biases and limitations, but certain questions, such as those involving the determination of activity patterns, often can be addressed using a non-trap biased approach (Reynolds 1982; Price and LaPointe 1990; Dalrymple et al. 199la; Dalrymple et al. 199lb; Bernardino and Dalrymple 1992). Inventory sampling should use a variety of techniques, such as pitfall traps with drift fences (Gibbons and Semlitsch 1982), road-cruising (Klauber 1939), coverboards (Grant et al. 1992), and time-constraint sampling (Campbell and Christman 1982), to supplement funnel trap data (Fitch 1992). LITERATURE CITED Anderson Bell. 1987. ABSTAT. Release 4. Parker, Colorado. Begon, M.,J. L Harper, and C. R. Townsend. 1986. Ecology: Individuals, populations and communities. Blackwell, Oxford Bernardino, F. S., Jr., and G. H. Dalrymple. 1992. Seasonal activity and road mortality of the snakes ofthe Pa-hay-okee wetlands ofEvergladcs National Park, USA Biol. Conserv. 62:71-75. 66 BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 38 PT. I(2) Campbell, H. W. and S. P. Christman. 1982. Field techniques for herpetofaunal community analysis. Pp. 193-200 in N. 1. Scott Jr., ed. Herpetological communities. U.S. Fish Wildl. Serv; Wildl. Res. Rept 13. Croker, T. C. 1979. The tongleafpine story. J. For. Hist. 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