Amphibian and reptile communities in eleven Sites of Community Importance (SCI): relations between SCI area, heterogeneity and richness Luca Canova1, Manuela Marchesi2 1Dipartimento di Biologia Animale, Università di Pavia, Piazza Botta 9, I-27100 Pavia, Italy. Corre- sponding author. E-mail: canova@unipv.it 2Assessorato Ambiente, Provincia di Lodi, Via Grandi 6, I-26800 Lodi, Italy Abstract. Seven species of amphibians and reptiles were observed in eleven Sites of Community Importance (SCI) of the Lodi Province (NW Italy). Distribution and rela- tive abundance of amphibians appeared more variable than reptiles. Some species of conservation concern as R. latastei were influenced by habitat physiognomy, i.e. the surface of wooded areas are important in predict presence and relative abundance of this species. SCI with wider surfaces and higher habitat heterogeneity included higher number of species. Species richness, here considered as a raw index of biodiversity value and community quality, was significantly related to SCI area and habitat hetero- geneity; since this significant positive relation is confirmed both for amphibians and reptiles we suggest that, in planning of natural areas, priority must be retained for biotopes able to host the higher number of species. Keywords. Amphibians, reptiles, SCI, richness, habitat heterogeneity, Italy. INTRODUCTION Animal communities are the results of two main differing forces; the ecological forces determine the stability of an assemblage, while the evolutive forces determine the pattern of coexistence between different populations (Stenseth, 1989). Communities parameters such as richness and species diversity are moreover influenced by several factors such as habitat surface and heterogeneity, and by a number of limiting factors, as management at ecosystem level, or vulnerability to allogenic invasions (Krebs, 2001). The indipendent analysis of these factors is often very difficult as well as their influence on animal commu- nity; scaling problem, for example, is one of the most difficult to resolve in several verte- brate community (Webb, 1989). Amphibian and, to a lesser extent, reptile communities are known to be vulnerable to several external enviromental factors such as managed altera- Acta Herpetologica 2(2): 87-96, 2007 ISSN 1827-9643 (online) © 2007 Firenze University Press 88 L. Canova and M. Marchesi tion of primaeval habitats (Ryan et al., 2002; Ernst et al., 2006), fragmentation (Russell et al., 2002), pollution (Lebboroni et al., 2006), infections (Bosch and Martinez-Solano, 2006; Rachowicz et al., 2006), and to wide-scale global change (Pounds et al., 2006). Due to this vulnerability, amphibians are considered as a good primer in evaluating habitat quality (Rondinini and Boitani, 2006). All these factors should be taken into account when amphibian/reptilian commu- nity parameters are investigated in protected areas, and when a correct planning should include patches size and habitat heterogeneity, aimed at improving conservation effort and its output (Freemark et al., 2006; Garcia, 2006). The aim of this study is to: (1) check for presence and abundance of amphibian and reptilian communities in the eleven Sites of Community Importance of the Lodi Province, (2) describe relationships between community richness, patches size and habitat hetero- geneity, and (3) check the suitability of the current asset of SCI of the Lodi Province for amphibian and reptilian conservation. MATERIALS AND METHODS The study was carried out from April 6, to July 29, 2003 in the eleven Sites of Community Importance of the Lodi Province (NW Italy, Fig. 1, Table 1). A Systematic Sampling System (SSS; Scott, 1994) was adopted during this study; in each biotope we conducted sistematic research aimed at identifying species, location and their relative abundance. A period of 60 min was adopted as standard effort time and at least a research session was carried out weekly in each biotope from late March to late July. Species were identified by means of capture, direct Fig 1. The eleven SCI surveyed: (1) Boschi e lanca di Comazzo, (2) Garzaia del Mortone, (3) Bosco del Mortone, (4) Garzaia della Cascina del Pioppo, (5) Spiagge fluviali di Boffalora , (6) Lanca di Soltarico, (7) La Zerbaglia, (8) Morta di Bertonico, (9) Adda Morta, (10) Bosco Valentino, (11) Monticchie. 89Amphibian and reptile communities in eleven SCI observation, collection of dead individuals, shed skins pellets or scats analysys. The total sampling effort was 170 h; sampling effort was equally distributed among biotopes in relation to their area. Relative abundance calculated by SSS was used in comparative analysis among species abun- dance. We calculated as richness (R) the number of species recorded during the study period in each biotope and as habitat eterogeneity a Shannon-Wiener index (H=-Σ pi log pi ) where pi is is the proportion of the partial area of the habitat i on the total area of the biotope (Ahabitat/Abiotope ) and A is the area covered by each habitat and biotope. Data analysis were carried out by SPSS 10.1 pack- age and Microsoft Excel. Relative surface of habitat, coordinates and EU codes for each SCI were obtained from the Regione Lombardia archive data. RESULTS Communities and local distribution A total of seven species of amphibians (Pelophylax synkl. esculenta, Pseudoepidalea viridis, Rana latastei, Bufo bufo, Hyla intermedia, Triturus carnifex, Lissotriton vulgaris) and seven species of reptiles (Podarcis muralis, Anguis fragilis, Lacerta bilineata, Hierophis viridiflavus, Natrix natrix, Natrix tessellata, Zamenis longissimus) were recorded in our study areas; taxonomical attribution are from Frost et al. (2006). Among amphibians P. synkl. esculenta is the most euritopic species and, together with R. latastei, P. viridis and H. intermedia are widely distributed in nearly all the study areas (Table 2); this data appeared of good conservation value, since R. latastei is an endemic species of the Po plain. The other amphibian species are irregularly distributed and newts were found only in few sites with permanent ponds (Table 2). Among reptiles P. muralis and N. natrix are the most euritopic species and, together with L. bilineata and H. viridiflavus, are widely distributed, as showed by evennes index Table 1. Locations, EU code and IGM coordinates and surface (in ha) of the 11 SCI under study. SCI name EU code IGM coordinates Area (ha) 1 Boschi e lanca di Comazzo IT2090002 45°25’44.36’’N; 9°27’48.69’’E 267 2 Garzaia della Cascina del Pioppo IT2090005 45°22’21.05’’N; 9°26’49.85’’E 6 3 Bosco del Mortone IT2090003 45°23’17.17’’N; 9°27’07.99’’E 63 4 Garzaia del Mortone IT2090004 45°23’21.43’’N; 9°26’09.86’’E 35 5 Spiagge fluviali di Boffalora IT2090006 45°21’04.84’’N; 9°28’34.60’’E 172 6 Lanca di Soltarico IT2090007 45°17’17.80’’N; 9°35’04.21’’E 170 7 La Zerbaglia IT2090008 45°16’41.10’’N; 9°38’25.85’’E 552 8 Morta di Bertonico IT2090009 45°15’17.92’’N; 9°39’45.17’’E 80 9 Adda Morta IT2090011 45°13’17.80’’N; 9°42’09.18’’E 191 10 Bosco Valentino IT2090011 45°12’34.20’’N; 9°45’48.99’’E 48 11 Monticchie IT2090001 45°08’41.16’’N; 9°39’27.91’’E 238 90 L. Canova and M. Marchesi ranging form 1 to 0.82 in nearly all the study areas; the other species are irregularly dis- tributed or strongly localized in a single biotope as Z. longissimus (Table 2). Species detectability and abundance differences The frequency of observation/recording was higher from April to June than in July, both for amphibians and reptiles. All amphibians were monthly detected from March to June while detectability of reptiles was slightly lower and not all species were found in the same period; observation rate slightly decreased in the last month of surveys for both taxa. Data analysis showed remarkably differences in relative amphibians abundance (Fig. 2); the most widespread P. synkl. esculenta is the most abundant specie (mean = 25.5 ind/ h), while abundance of R. latastei, despite its wide local distribution, is constantly less Table 2. Local distribution of species. Evennes index showed how wide species distribution is (index range from 1 for euritopic species to 0 for stenotopic species). 1 B os ch i e la nc a di C om az zo 2 G ar za ia d el M or to ne 3 B os co d el M or to ne 4 G ar za ia d el la C as ci na d el Pi op po 5 Sp ia gg e flu vi al i d i B off al or a 6 La nc a di S ol ta ri co 7 La Z er ba gl ia 8 M or ta d i B er to ni co 9 A dd a M or ta 10 B os co V al en tin o 11 M on tic ch ie Ev en ne s Pelophylax synkl. esculenta + + + + + + + + + + + 1 Rana latastei + + + + + + + + + + 0.91 Pseudoepidalea viridis + + + + + + + + + 0.82 Bufo bufo + + + + + 0.45 Hyla intermedia + + + + + + + 0.64 Triturus carnifex + + + 0.27 Lissotriton vulgaris + + 0.18 Podarcis muralis + + + + + + + + + + + 1 Lacerta bilineata + + + + + + + + + + 0.91 Anguis fragilis + + + 0.27 Natrix natrix + + + + + + + + + + + 1 Hierophis viridiflavus + + + + + + + + + 0.82 Natrix tassellata + + + + + 0.45 Zamenis longissimus + 0.09 91Amphibian and reptile communities in eleven SCI abundant (mean = 3.18 ind/h). The abundance of the former species is apparently unrelat- ed to habitat physiognomy, while R. latastei abundance increased to increasing of wooded areas (rs = 0.82, n = 10, P = 0.03). Abundance pattern showed by H. intermedia and P. viridis, the only other amphibian species for which enough data were collected, is somewhat erratic; P. viridis appeared a localised species with very scarce populations, while H. intermedia is more widely distrib- uted, indipendently of the amount of wooded habitat (rs = 0.44, n = 10, P = 0.20, Fig. 2). Reptiles abundance appeared less variable; Podarcis muralis is the most abundant species in all the habitats and, together with L. bilineata, is widespread in the study area. Snakes are widely distributed, showing a very low relative population abundance (Fig. 3). Relation between richness and habitat area and heterogeneity Data showed that pooled species richness and biotope area were significantly and pos- itively related (richness = 0.45 × Ln(area) + 0.63, R2 = 0.73, P = 0.004; Fig. 4a), and fur- thermore that a significant relation existed considering richness of each individual group, Fig. 2. Relative abundance of Rana latastei, Pelophylax synkl. esculenta, Hyla intermedia and Pseudoepi- dalea viridis. 92 L. Canova and M. Marchesi (i) amphibians (richness = 0.59 × Ln(area) + 0.23, R2 = 0.69, P = 0.004), and (ii) reptiles (richness = 0.38 × Ln(area) + 0.39, R2 = 0.72, P = 0.003). Moreover, we observed a significant relation between pooled species richness and habitat diversity (richness = 0.45 × Ln(habitat diversity) + 1.11, R2 = 0.58, P = 0.02), and that such relation was significant, thought with a lower predictive value, when considering separately amphibians (richness = 0.51 × Ln(habitat diversity) + 0.38, R2 = 0.52, P = 0.027) and reptiles (richness = 0.34 × Ln(habitat diversity) + 0.78, R2 = 0.47, P = 0.032, Fig. 4b). DISCUSSION Following previous research and surveys, the presence of nine amphibians and eleven reptile species had been verified in the southern Po plain (Lodi Province, Bernini et al., 2004a). During the current study Pelobates fuscus and Rana dalmatina were not recorded among amphibians, and Emys orbicularis, Podarcis sicula, Coronella austriaca and Vipera aspis among reptiles. In summary, current results showed that nearly 78% of known Fig. 3. Relative abundance of Podarcis muralis, Lacerta bilineata, Natrix natrix and Hierophis viridiflavus. 93Amphibian and reptile communities in eleven SCI amphibians and 63% of known reptiles are present in the SCI. This data can be interpreted in two alternative ways: first, SSS method might fails to detect the most elusive species or secondly, SSS method might reflect the actual relative abundances of species. The preva- lence of unrecorded species among reptiles probably reflected both their local rarity (such as for E. orbicularis; Chelazzi et al., 2000; Ferri and Zuffi, 2004), low detectability (e.g. C. austriaca) as well as patterns of local distribution (P. sicula and V. aspis are known to be present in areas out of the current SCI network). Species detectability is high during the spring season and showed a slight decrease in July, the warmer month; at our latitude the SSS method appeared to be more profitable in early spring than in summer (probably from late winter, i.e. February, for some species as R. latastei and R. dalmatina that are early breeders and this suggestion can be assumed as a methodological improvement at least for the Italian northern distributive area of the species under study. Detailed analysis on population abundance are clearly precluded by speditive methods adopted during the presents study; only a few species as P. synkl. esculenta and P. muralis Fig. 4. Relation between richness (R) versus SCI area (above) and versus structural diversity (H) of biotopes (below) (data are log transformed). 94 L. Canova and M. Marchesi are relatively common. Relative abundance of other species as P. viridis, appeared lower than expected; in some sectors of the Po plain P. viridis is considered a declining species, as previously reported for some European populations (Honegger, 1981); the most com- mon threaths to its conservation are identified in the reduction of temporary pond (Boni- ni and Bressi, 2004), and this can partially explain the reduction of the species’ population over large areas. We suggest that a general reduction of ponds along the main course of a number of large rivers, and the late egg-laying period (May-June), can heavily influence the reproductive performances of P. viridis in the dry flood plain of the Adda river, an habitat dynamics not shared by other amphibian species which reproduced earlier. Similar conditions are shared by B. bufo, apparently a species very scarce in our study areas, whose reduction could it be possibly influenced by the delayed effects of agricolture intensive practices (Pavignano and Giacoma, 1990). The pattern of local distribution of some species, as R. latastei, appeared influenced by habitat physiognomy; the relative abundance of this species is significantly related to the area of wooded patches, a data confirming current informations on its ecology (Barbieri and Bernini, 2004a); in our study areas R. latastei is abundant in patches of ancient oak woodland (Bernini et al., 2004), characterized by high pond availability in early spring; if temporary ponds are available at the start/beginning of breeding season, the species can colonize poplar groves and seminatural wooded habitats. Analysis of relation between community parameters and habitat size and physiognomy showed that SCI with wider/larger surfaces and higher habitat heterogeneity included an higher number of species. It is well known that biodiversity cannot be expressed only by richness index, since quantitative parameters as abundance and density, and genetic char- acteristics of populations should be taken into account as well; however richness index can be considered as a raw, sinthetic index of community quality. Since the significant positive relation between richness and habitat area, and heterogeneity is confirmed separately both for amphibians and reptiles, we suggest that, in planning of protected areas, priority must be retained for large and heterogeneous biotopes. In this framework, however, a passive protection scheme can be unsuitable to guarantee a safety level of protection for some spe- cies; more resources must be devoted in paying attention to both conservation measures and obtained results (Watzold and Schwerdtner, 2005). Despite of the possible failure of SSS methodology in elusive species detection, we must take into account the actual function of Natura 2000 in protecting local biodiversity. Our data did not exclude that the establishment of a continental network of protected are- as did not ensure a good level of conservation on local scale, at least for some species of reptiles. In this framework an higher effort in looking for additional spatial and biological indicators is then auspicable (Bock et al., 2005; Papageorgiou and Vogiatzakis, 2006). ACKNOWLEDGEMENTS Thanks are due to owners of SCI for access permission and facilities and to several students who helped us in data collecting. A. 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