Diversidade e distribuição potencial de assembleias de serpentes na Amazônia

Abstract

To understand the patterns of species diversity has always been one of the great questions in Ecology, especially on environments with high heterogeneity and rich biodiversity such as the Amazonia. One of the groups with high diversity in this biome is the snakes, currently comprising about 225 species. Many studies (e.g., ecological, natural history, genetics) have been performed with snakes over the last decade but there is still a large gap of information about taxonomic and phylogenetic diversity, as well as species distribution. The reason resides on the fact that snakes are cryptic animals and very difficult to spot, especially in regions with dense forests like Amazonia. Therefore, studies about taxonomy, richness, spatial and biogeographical distribution of snake’s biota are urgent, particularly considering the elevate degree of threat Amazonia region is suffering mostly related to human activities. This study is organized in three chapters with distinct goals but all converging to provide scientific basis towards biodiversity conservation. In the Chapter I we reported the composition of snake assemblages in six poorly explored regions in Brazilian Amazonia, based on four years of field sampling using standardized methods. It was possible to verify that the diversity of snakes is greater than expected, which was supported by the sampling of at least three groups of individuals that could not be identified at species level and for the high rate of species replacement among assemblages. We also demonstrated that standardized faunal inventories in poorly sampled areas in the Amazon biome are of paramount importance. In the Chapter II we used Species Distribution Modeling (SDMs) to test if snake species are widely distributed in the biome and which variables modulate this potential distribution. Most of species do not show a broad habitat suitability being the East and West of Amazonia the most suitable regions. Finally, we observed that vegetation and precipitation modulate the species distribution in Amazonia. In Chapter III we investigated the cryptic diversity of snakes in the biome by using extended phylogenies and a biogeographic model. We verified that the diversity of snakes is underestimated at up to 19,6% and emphasized the importance of taking species crypticity and their evolutionary histories into consideration, particularly in large scale studies and heterogeneous environments such as Amazonia.