Herpetofauna of Núcleo Experimental de Iguaba Grande , Rio de Janeiro state , Brazil

The Atlantic Rain forest, which is considered the second largest pluvial forest in the American continent, has had an estimated 93% of its original area destroyed. Although studies concerning the herpetofaunal diversity in this biome have been intensified in the past years, its diversity is still underestimated. The Nucleo Experimental de Iguaba Grande (NEIG) is included in an Environmental Protection Area (APA de Sapeatiba) in the Iguaba Grande municipality, Rio de Janeiro state, Brazil (22° 51’ S and 42° 10’ W). The goal of this study was to conduct an inventory of the reptile and amphibian species that occur in this area between July 2008 and December 2009. We recorded 19 species of amphibians (18 anurans and one caecilian) and 15 species of reptiles (three lizards, 11 snakes and one amphisbaenian). Leptodactylus latrans and L. mystacinus had the highest capture rates among amphibians captured, and among reptiles, Ameiva ameiva, Hemidactylus mabouia and Mabuya agilis had the highest capture rates. Rarefaction curves for both amphibians and reptiles did not reach the asymptote, indicating that the species richness in the NEIG is still underestimated.

The Atlantic Rainforest originally covered a total area equivalent to approximately 13% of Brazil, and it is estimated that more than 93% of this original area has been destroyed (IPEMA, 2005).Despite the enormous amount of anthropic disturbances, this biome still harbours a significant portion of the biological diversity in Brazil (IPEMA, 2005;MYERS et al., 2000).
In the state of Rio de Janeiro, in particular, the Atlantic Rainforest remnants currently represent around 20% of its original area (Fundação SOS Mata Atlântica;INPE, 2001).Although conservation initiatives have grown in number and scale over the past two decades, they are still insufficient to properly ensure the conservation of biodiversity in the Atlantic forest (Tabarelli et al., 2004).
In this work, we present results of a herpetofaunal survey, which was conducted on a predominantly restinga habitat within the Atlantic Rainforest biome in the state of Rio de Janeiro, in order to provide data about the local species composition.

Study site
This study was conducted in The Núcleo Experimental de Iguaba Grande (NEIG/UFF -22° 51' S and 42° 10' W), located within the municipality of Iguaba Grande, in the state of Rio de Janeiro, Brazil (Figure 1).This area is located within the Environmental Protection Area (APA) of Sapeatiba, with an area of 169.4 ha, of which 135.52 ha are composed of restinga and dry forest, and 33.88 ha by disturbed areas.The NEIG consists of a mosaic of habitats marked by the presence of some patches of typical restinga vegetation, tropical dry forest and disturbed areas (Vecchi and Alves, 2008), and is located approximately 11 km from the Atlantic Ocean, bounded northward by the RJ-106 highway and southward by the Araruama lagoon (CPRM, 2000).Moreover, the NEIG represents the most conserved remnant area in the northern portion of Araruama Lagoon Basin (Silveira-Primo and Bizerril, 2000).In the study area, the restinga habitats are restricted to the southern edge, which faces the Araruama lagoon and consists of typical restinga vegetation.The dry forest habitats are the predominant vegetation types in the area, extending from the northern edge of the area, through the central portions until facing the restinga areas in the southern edge.It consists of a shrubby area with evenly-spaced trees that are adapted for an arid climate and high intensity winds (Silveira-Primo and Bizerril, 2000).The disturbed areas consist of those that have been occupied by buildings or those that have been cleared for use as pasture (S.F.Bruno pers.comm.; Figure 1).Moreover, the boundaries of these different vegetation types are difficult to discern probably because this area has not been the object of specific studies of its vegetation (Lamego, 1974;Vecchi and Alves, 2008).

Data collection
Fieldwork was conducted between two and four consecutive days bimonthly from July 2008 to December 2009.Searches occurred during the day and at night, and totalled 36 field trips, 91 days and 54 nights of fieldwork.During data collection, the number of collectors ranged from one to four per day.The herpetofauna was sampled through the use of pitfall traps with drift fences (Cechin and Martins, 2000); active searches (not time-constrained) (Heyer, 1994) and occasional encounters.Pitfall systems were distributed along four lines.Each line was set in one vegetation type -Line 1: dry forest; Line 2: restinga; Line 3: transition between restinga and dry forest; and Line 4: disturbed area (Figure 2).Each line contained eight 60-litre buckets with small holes and a sheet of styrofoam at the bottom.The buckets were buried in the ground, set five metres apart from each other, and linked by plastic fences 60 cm high.The traps were opened during all days of the study (from July 2008 to December 2009), and checked every day, or every two days, totalling 405 hours of sampling effort per bucket.
The active searching method consisted in walking slowly along the pre-existing roads and trails of the NEIG and searching every type of microhabitat (e.g.leaf litter, twigs, trunks, under stones, in stumps, holes in the ground and in hollow trees).This method was performed during the morning, afternoon and evening, totalling 900 hours off effort.Occasional encounters with live animals and carcasses found in the NEIG were also considered for the diversity data results.
Representative specimens of each species were fixed in 10% formalin and housed as vouchers at the Museu Nacional, Universidade Federal do Rio de Janeiro (MNRJ).Other captured specimens not intended as representative specimens were released near their original capture location.The collection of specimens was permitted by IBAMA (license numbers: 16584-1 and 16584-2).

Data analysis
We used the Kruskall-Wallis H-test to check the significance of the difference between capture rates in all four pitfall lines.Tests were performed using the Statistica 7 program, and were based on the period in which all lines had the same bucket/hour sampling (i.e.February 2009 to August 2008; 1040bucket-hours).
In order to check sample efficiency, we used the program EstimateS (version 6.0b1) to obtain a rarefaction curve of the sampled amphibians and reptiles.The curve was obtained through 1000 randomizations and using a Jackknife estimator.
Rarefaction curves of both amphibians and reptiles did not reach the asymptote (Figure 2).
Among the amphibian species recorded at the NEIG, Leptodactylus latrans and L. mystacinus had the highest capture rates, which together represented 70% of individuals captured (Figure 3a).Furthermore, these two anuran species were found in all vegetation types, including temporary water bodies in both restinga and dry forest and in disturbed areas (Figure 4a).The species Phyllomedusa rohdei, Scinax fuscovarius, Scinax similis, Scinax aff.x-signatus, Denderopsophus elegans, Dendropsophus meridianus, Scinax littoreus and Sphaenorhynchus planicola had more than 10 captures each, whereas the other species not mentioned above had less than 10 captures each (Figure 3a).
Among reptile species recorded, A. ameiva, M. agilis and H. mabouia (all lizard species recorded in this study) had the higher capture rates, with more than 65 captures each (Figure 3b).Together, these three lizard species represented 80% of the total of individuals recorded.The snake species Tantilla sp. and O. aeneus had more than 10 captures each in this study, whereas other snake species had lower capture rates, (i.e., <6 captures each; Figure 4b).Differences between capture rates in each pitfall line was not significant for both amphibian (H = 3.8, df = 3, p = 0,29) and reptile species (H = 4.0, df = 3, p = 0,26).

Amphibian community
The amphibian species diversity in the NEIG resembles those reported in other studies conducted in restinga habitats along the Brazilian coast (e.g., Britto-Pereira et al., 1988;Carvalho-e-Silva et al., 2000;Rocha et al., 2008;Silva et al., 2008), with the family Hylidae also being the most representative family among recorded amphibians.
Most of the amphibian species registered for NEIG were recorded from restinga habitats (Figure 4), in which the animals were commonly associated with bromeliads or near temporary water bodies, with the highest capture rates occurring during the rainy seasons.
Except for Scinax littoreus, Trachycephalus nigromaculatus, Phyllomedusa rohdei, P. burmeisteri and Dendropsohus elegans, the other species were associated with permanent water bodies in restinga habitats in the NEIG.Scinax littoreus was recorded only inside bromeliads in bushy restinga habitats.Trachycepahlus nigromaculatus was found inside bromeliads in dry forest and in shrubby and bushy areas of restinga habitats.Dendropsophus elegans and P. rohdei were both found in the dry forest after rainy periods or associated with water bodies near the bushy areas and bromeliads.Phyllomedusa burmeisteri had a single record for dry forest vegetation near a water body distant from the coast.
Among amphibian species registered in the present study, with the exceptions of Sphaenorhyncus planicola, Scinax littoreus and Rhinella pygmaea, all other species recorded have a wide distribution in the Atlantic Forest (Haddad et al., 2008).Leptodactylus latrans and Trachycephalus nigromaculatus can also occur in the Cerrado and the Amazon (Haddad et al., 2008;Dias et al., 2010).Scinax fuscovarius and Leptodactylus mystacinus are also known to occur in the Cerrado and Caatinga biomes (Freitas and Silva, 2007).Sphaenorhyncus planicola has a restricted distribution in the Atlantic forest, only occurring in the states of Rio de Janeiro and Espirito Santo, while Scinax littoreus and Rhinella pygmaea are endemic to restinga environments (Carvalho-e-Silva et al., 2000;Rocha et al., 2008).
Although S. fuscovarius was found to be associated with the restinga habitats in the present study, this species was not listed by Rocha et al. (2008) for some restingas of Rio de Janeiro, Espirito Santo and Bahia states, nor by Carvalho-e- Silva et al. (2000) for restingas along the Brazilian coast.Trachycepahlus nigromaculatus, Dendropsophus elegans and P. rohdei had been listed for restinga habitats in southeastern Brazil by Carvalho-e- Silva et al. (2000), but were not present in the listings of Rocha et al. (2008) for restingas of Rio de Janeiro, Espirito Santo and Bahia states.Although the single record of Phyllomedusa burmeisteri occurred outside the typical restinga areas, this species Table 1.List of amphibian and reptile species registered on the NEIG, in Iguaba Grande, Rio de Janeiro state, Brazil, with sampling methods and sampled habitats.
had been listed by Carvalho-e- Silva et al. (2000) to occur in restinga habitats in southeastern Brazil.
Leptodactylus latrans and Leptodacytlus mystacinus had the highest capture rates, besides being captured in all vegetation types in the study area.These species have wide distribution in Brazil, and are favoured by their adaptability and resistance to disturbed areas (Izecksohn and Carvalho-e-Silva, 2001;Haddad et al., 2008).
None of the species recorded in the area was included on the national list of threatened amphibian species (IBAMA, 2003).The lone record for the caeciliid Chtonerpeton sp., from our study may represent a species that has not yet been formally described (see Rocha et al., 2004b).Flectonotus sp. could not be identified because the single collected specimen was an immature, making it difficult to identify the specimen.

Reptile community
Similar to the amphibian diversity, reptile diversity in the NEIG resembles the findings of other studies conducted in restinga habitats along the Brazilian coast (e.g.Rocha et al. 2004a;Dias and Rocha, 2005; Carvalho et al., ).None of the species recorded in the area is included on the national list of threatened reptile species (IBAMA, 2003).
Ameiva ameiva, Boa constrictor, Philodryas patagoniensis, Hemidactylus mabouia and Oxybelis aeneus were widely distributed in the area, covering all areas of the study site.Mabuya agilis was restricted to the border of dry forest areas and to shrubby restinga areas.The distribution of this species in the study area may be heavily influenced by the higher concentration of grasses in the recorded habitats, limiting its distribution to these habitats (Rocha and Bergallo, 1997).Leptophis ahaetulla, Philodryas.olfersii and Oxyrhopus petola were restricted to dry forest areas, while Micrurus ibiboboca and Chironius bicarinatus were recorded in both dry forest and bushy areas of restinga habitats after rainy days.Liophis miliaris has only been recorded near permanent water bodies, which can be explained by its semi-aquatic habit (Pontes and Rocha, 2008).Our record of Typhlops brongersmianus for Iguaba Grande expands to the south the species previous known range the state (Martins et al., 2010).The distribution of Amphisbaena scutigera within NEIG was not determined because only a single specimen was found dead on the highway that borders the study area.All records for the Tantilla sp.-which could not be identified at species level because it might represent a new species -were all restricted to better preserved areas (all areas of restinga and dry forest).
Except for Micrurus ibiboboca, which may also be found in the Caatinga region of northeast Brazil (Vanzolini et al., 1980;Campbell and Lamar, 2004), and Tantilla sp., other snake records included species with wide distribution in most Brazilian biomes (Pontes and Rocha, 2008), as well as in other countries.Boa constrictor can be found not only  and Rocha, 2008).O. aeneus, P. olfersii and L. ahaetulla may be found in areas of the Atlantic Rainforest and also in the Amazon (Pontes and Rocha, 2008).
Hemidactylus mabouia and Ameiva ameiva have wide distributions in Brazil, occurring also in the Amazonia, Cerrado and Caatinga biomes (Freitas and Silva, 2007), while Mabuya agilis occurs continuously along much of the southeastern Brazilian coast from Rio de Janeiro to southern Bahia (Rocha and Bergallo, 1997;Rocha, 2000).These species had the highest capture rates registered in the NEIG the most abundant lizards in Brazilian restingas (Rocha and Bergallo, 1997).
Tropidurus torquatus and Ameiva ameiva were the only species that occurred in all restingas studied along southeastern and northeastern Brazil .The species T. torquatus was the most abundant species in all restingas, which seems to result from the considerable generalization of several aspects of the species ecology, diet, activity and reproductive aspects (Araújo, 1984;Bergallo and Rocha, 1993;Rocha and Bergallo, 1994;Teixeira-Filho et al., 2003;Gandolfi and Rocha, 1998).These generalized characteristics (in relation to other species) probably allow T. torquatus to maintain a high population size in restingas (Rocha and Bergallo, 1997).However, our results show that T. torquatus was not registered in the study area, and it was not even seen in the surrounding areas.These data lead us to question the absence of the species in the study area; nevertheless, more focused studies are still necessary in order to answer such question.Ecological factors, along with the age and the state of restinga formations as well as the processes of colonization by species of reptiles are responsible for a considerable part of the composition, structure and organization of these communities in restinga habitats (Rocha, 2000).However, with the current limitations of knowledge about the communities of reptiles and the processes occurring in the past and present in such habitats, studies are still needed to achieve a greater understanding of historical factors and ecological determinants of the variation between areas in reptiles communities (Rocha and Bergallo, 1997).
Although the sampling period exceeded one year, the rarefaction curves for both amphibians and reptiles did not reach the asymptote.These results suggest that the species richness in the NEIG is still underestimated, and more long-term studies are necessary for understanding the composition of the amphibian and reptile fauna species in the studied area.

Conclusion
The herpetofaunal diversity in the NEIG is similar to other restinga diversity studies along the Brazilian coast, and these results contribute to the herpetofaunal knowledge of the Brazilian Atlantic Rainforest diversity.
Although the NEIG represents a small remnant of Atlantic Rainforest, the records obtained in this study reinforce the need and importance of studies and conservation on the herpetofaunal composition in small remnants of this biome, which can still harbour undescribed and/or threatened species.Moreover, further detailed studies of the herpetofaunal composition are crucial for taking conservation measures and forming management plans suitable not only for Environmental Protection Areas, but also for many remaining areas of Atlantic Rainforest.

Figure 1 .Figure 2 .
Figure 1.Location of the study area of Nucleo Experimental de Iguaba Grande, Iguaba Grande municipality, Rio de Janeiro state, southeastern Brazil, and characterization of the three vegetation types in the NEIG: restinga, dry forest and disturbed area.Dots indicate lines of pitfall traps used in the study, each one established in one vegetation type.Line 1: Dry forest, Line 2: Restinga, Line 3: Transition between dry forest and restinga, Line 4: Disturbed area.

Figure 3 .
Figure 3. Number of captures of amphibian (a) and reptile (b) species in Núcleo Experimental de Iguaba Grande, Rio de Janeiro state.

Figure 4 .
Figure 4. Capture rates (%) per species of amphibians (a) and reptiles (b) in pitfall traps and during active search in three habitats of Núcleo Experimental de Iguaba Grande, Rio de Janeiro state.White bars = dry forest; gray bars = disturbed area; Black bars = restinga.