2016-12-23T18:52:10

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Abstract:Neotropical snake assemblages present high species richness and complex structures. The Cerrado is the second largest biome in Brazil, and was included among the 25 World's biodiversity hotspots. In southeastern Brazil, the remnant Cerrado areas have suffered intense destruction, and presently less than 2% of Cerrado natural vegetation remain in São Paulo state. Virtually no detailed study on Cerrado snakes was carried out in this region. The Itirapina region has one of the last well preserved remnants of open cerrado in São Paulo state. Our purpose in this work was the study of natural history and composition of the Cerrado snakes of Itirapina region. We performed an extensive field sampling combining six sampling methods in Estação Ecológica de Itirapina and disturbed Cerrado areas in its surroundings (municipalities of Itirapina and Brotas), during 101 trips throughout 43 months, between September 1998 and March 2002, corresponding to 446 days of field sampling. We also collected additional data from museum specimens housed in scientific collections. We present data on size, general abundance, habitat and macrohabitat use, daily and seasonal activity, feeding, reproduction, and defense. We also compared the Itirapina snake assemblage with nine snake assemblages of Brazil, from Amazonia, Atlantic Forest, Cerrado, and other open habitats. We recorded a total of 36 snake species among 755 individuals found in the field and six records from scientific collections and literature, belonging to 25 genera and five families. The snake assemblage comparisons indicate that the Cerrado has its own identity regarding the snake composition. Although small (about 2,300 ha), the Estação Ecológica de Itirapina encompasses well preserved and representative Cerrado physiognomic forms, which harbors a rich and typical Cerrado snake fauna. The occurrence of some species only inside the reserve also indicates that the Estação Ecológica de Itirapina is of fundamental importance to the maintenance of Cerrado biodiversity.

The present study is a synthesis on snake diversity and distribution in the Caatinga region of northeastern Brazil, providing an updated species list and data on natural history and geographic distribution. Our study is based on the careful revision of 7,102 voucher specimens, housed in 17 herpetological collections, complemented by data on taxonomic literature. We recorded a total of 112 snake species in the Caatinga, belonging to nine families: Anomalepididae, Leptotyphlopidae, Typhlopidae, Aniliidae, Boidae, Viperidae, Elapidae, Colubridae, and Dipsadidae. Our list includes at least 13 never recorded species for this region, as well as distribution records for all species known from the Caatinga (including expansion and new records of distribution). The snake assemblage of the Caatinga is complex, sharing species with other continental open areas (38.4%), forested areas (27.7%), and both open and forested areas (32.1%). The richest areas were isolated plateaus, followed by contact areas, semi-arid caatinga, and sandy dunes of the São Franscisco River. We identified 22 Caatinga endemic species with the sandy dunes of São Franscico River showing the highest endemism level (12 species, with six endemic species restricted to the area) followed by semi-arid caatinga, and isolated plateaus (eight endemic species each, and six and three endemic species with restricted distribution to each area, respectively). Most species show relatively restricted ranges in parts of the Caatinga. The snake assemblage in Caatinga includes mainly terrestrial species (38.4%), followed by fossorial/cryptozoic (26.8%), arboreal/semi-arboreal (26.8%), and aquatic/semi-aquatic (7.1%) species. Vertebrates are the most important dietary item (80.4%), with 56.6% of species being generalist consumers of this kind of prey; 24.4% are frog-eaters, 7.8% prey on caecilians/amphisbaenians, 6.7% lizard-eaters, 3.3% mammal-eaters, and 1.1% are fish-eaters. Only 18.7% of the snakes eat invertebrate prey, as arthropods, annelids, and mollusks. In relation to time of activity, 35.7% of snakes are both diurnal and nocturnal, 33.0% are strictly nocturnal, and 30.4% are diurnal. The data provided herein increase the list of Caatinga snake species from 50 to 112, and includes detailed maps and information on geographic distribution. The Caatinga snake assemblage shows high richness and endemism levels, and our results highlight the usefulness of basic natural history data and revision of voucher specimens as baseline information for biogeographic studies and conservation strategies.

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O Município de São Paulo é uma área bem amostrada em relação à fauna de répteis devido à coleta intensiva feita pela população local nos últimos 100 anos. Neste trabalho consultamos registros e examinamos exemplares de coleções científicas para elaborar uma lista das espécies da região. A fauna de répteis também foi caracterizada em relação a três parâmetros ecológicos: uso do ambiente, uso de substrato e hábitos alimentares. Registramos um total de 97 espécies de répteis (dois quelônios, um crocodiliano, 19 lagartos, sete anfisbenídeos e 68 serpentes). Aproximadamente 70% da fauna de lagartos e 40% das serpentes é composta por espécies típicas de ambientes florestais e ocorrem na Serra do Mar. Outros squamata são característicos de formações abertas e são encontrados, sobretudo nas formações abertas de Cerrado do interior paulista. Todas tartarugas e o crodiliano estão associados a corpos da água. Aproximadamente 63% dos lagartos são predominantemente terrícolas e os demais são arborícolas. A maior parte das espécies de serpentes é terrícola (38%) ou subterrânea/criptozóica (25%), menor parte é arborícola (18%) ou aquática (9%). Artrópodes são o item predominante na dieta de lagartos. Quase 50% das espécies de serpentes alimentam-se exclusivamente ou predominantemente de anfíbios anuros. Outros itens alimentares importantes são mamíferos (24%), lagartos (18%), vertebrados subterrâneos (10%) e invertebrados (minhocas, moluscos e artrópodes; 15%). Um total de 51 espécies não tem sido registrado ao longo dos últimos seis anos no município. Provavelmente muitas dessas espécies já estão extintas na região em função da intensa urbanização e perda de hábitats. O levantamento de espécies coletadas no Município de São Paulo e recebidas pelo Instituto Butantan em anos recentes permitiu identificar pelo menos 42 espécies de serpentes e 10 lagartos que ainda ocorrem na região. A elevada riqueza desta fauna pretérita parece ser decorrente da localização geográfica do município, que, no passado, apresentava um mosaico de áreas florestais de Mata Atlântica e formações naturais abertas (cerrados, campos de altitude). Desse modo, a região deveria permitir originalmente a ocorrência concomitante de muitas espécies de áreas florestais e abertas. A fauna de serpentes atual registrada ao longo dos últimos três anos indica que houve uma perda maior da biodiversidade de espécies de formações abertas em relação àquelas de formações florestais.

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