Composição faunística, ecologia e história natural de serpentes em uma região no sudoeste da Amazônia, Rondônia, Brasil
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Data
2004-09-15
Autores
Bernarde, Paulo Sérgio [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Em Espigão do Oeste (Rondônia) foi registrada uma riqueza de 56 espécies de serpentes, apresentando uma maior similaridade faunística com a Usina Hidrelétrica de Samuel (RO), localizada relativamente próximo da área de estudo. As serpentes mais comuns foram Liophis reginae (18,6% do total), Oxyrhopus melanogenys (8,4%), Chironius exoletus (6%), Boa constrictor (5,8%), Dipsas catesbyi (5,6%) e Drymarchon corais (5,6%). A freqüência de Bothrops atrox, o viperídeo mais abundante na Amazônia, foi considerado baixo (2%). Um menor número de serpentes foi registrado durante os meses mais secos (junho - agosto), que também coincidiu com a menor ocorrência de anfíbios anuros. Observando a freqüência de potenciais presas (anuros, lagartos, marsupiais e roedores) sazonalmente registrada através das armadilhas de interceptação e queda (todos os grupos), procura limitada por tempo (lagartos dormindo sobre a vegetação à noite e anuros em atividade de vocalização), observa-se que houve disponibilidade de alimento ao longo do ano, embora cada grupo tenha ocorrido em diferentes níveis e picos de abundância. Os principais tipos de presas utilizados pelas serpentes nesta comunidade são lagartos (55,3% das espécies), seguido de anuros (48,2%), mamíferos (26,8%), aves (12,5%) e serpentes (12,5%). Uma análise de agrupamento utilizando dados de tamanho (comprimento rostro-cloacal) e de utilização de recursos (hábitos alimentares, período e substrato de forrageio) originou oito grupos (guildas) de serpentes. Nesta análise de agrupamento, foram reunidas tanto espécies próximas como distantes filogeneticamente, denotando a importância de fatores históricos e ecológicos na estruturação desta comunidade. Maior número de espécies de serpentes foi encontrado dentro de florestas, em relação aos ambientes de pastagens, demonstrando o decréscimo de espécies...
A snake richness of as much as 56 species was recorded at Espigão do Oeste (Rondônia). This makes the studied area faunistically similar to the Samuel Hydroelectric Plant (Rondônia), which is located close to it. The commonest snakes were Liophis reginae (18.6% of the total), Oxyrhopus melanogenys (8.4%), Chironius exoletus (6%), Boa constrictor (5.8%), Dipsas catesbyi (5.6%) and Drymarchon corais (5.6%). It is noticed a low frequency of Bothrops atrox (2%), the most abundant viperid in the Amazon. A lesser number of snakes was recorded during the driest months (from June to August), when there was a lesser occurrence of anuran amphibians as well. By seasonally observing the frequency of potential prey (anurans, lizards, marsupials and rodents), recorded by means of pitfall traps with drift fences (all groups) and time constrained search (lizards sleeping on the vegetation at night and calling anurans), it is noticed that there was availability of food supply throughout the year, although each group occurred at different abundance levels and peaks. Lizards (55.3% of the species), followed by anurans (48.2%), mammals (26.8%), birds (12.5%) and snakes (12.5%), are the main prey for the snakes in this community. A cluster analysis was carried out to produce a dendrogram with information on size (snout-vent length), feeding habits, period and forage substratum. Eight guilds of snakes were formed, according to the similarities in the use of resources. This cluster analysis grouped together species that, phylogenetically, were either close or distant, in order to mark the importance of historical and ecological factors to the structuring of this community. Most snake species were found throughout forested lands more than on pasture lands, showing that the weaker the vegetal structure, the lesser the number of species. Among the causes that may be enhancing or restraining the occurrence...(Complete abstract click electronic access below)
A snake richness of as much as 56 species was recorded at Espigão do Oeste (Rondônia). This makes the studied area faunistically similar to the Samuel Hydroelectric Plant (Rondônia), which is located close to it. The commonest snakes were Liophis reginae (18.6% of the total), Oxyrhopus melanogenys (8.4%), Chironius exoletus (6%), Boa constrictor (5.8%), Dipsas catesbyi (5.6%) and Drymarchon corais (5.6%). It is noticed a low frequency of Bothrops atrox (2%), the most abundant viperid in the Amazon. A lesser number of snakes was recorded during the driest months (from June to August), when there was a lesser occurrence of anuran amphibians as well. By seasonally observing the frequency of potential prey (anurans, lizards, marsupials and rodents), recorded by means of pitfall traps with drift fences (all groups) and time constrained search (lizards sleeping on the vegetation at night and calling anurans), it is noticed that there was availability of food supply throughout the year, although each group occurred at different abundance levels and peaks. Lizards (55.3% of the species), followed by anurans (48.2%), mammals (26.8%), birds (12.5%) and snakes (12.5%), are the main prey for the snakes in this community. A cluster analysis was carried out to produce a dendrogram with information on size (snout-vent length), feeding habits, period and forage substratum. Eight guilds of snakes were formed, according to the similarities in the use of resources. This cluster analysis grouped together species that, phylogenetically, were either close or distant, in order to mark the importance of historical and ecological factors to the structuring of this community. Most snake species were found throughout forested lands more than on pasture lands, showing that the weaker the vegetal structure, the lesser the number of species. Among the causes that may be enhancing or restraining the occurrence...(Complete abstract click electronic access below)
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Reptil, Reptile
Como citar
BERNARDE, Paulo Sérgio. Composição faunística, ecologia e história natural de serpentes em uma região no sudoeste da Amazônia, Rondônia, Brasil. 2004. ii, 134 f. Tese (doutorado) - Universidade Estadual Paulista, Instituto de Biociências de Rio Claro, 2004.