Diversidade regional de serpentes na Amazônia: uma abordagem multidimensional com implicações para conservação de paisagens naturais

Abstract

The overexploitation of natural resources have threatened tropical forests at an alarming rate, and integrative studies are necessary for planning effective conservation actions. In this thesis we used snakes as a model-group in studies on community ecology and landscape genomics in three chapters with different goals, but all converging in scientific basis for biodiversity conservation. In the Chapter I we present a cost-benefit evaluation of sampling snakes for environmental impact assessments in the Amazon. We show that the high cost of sampling snakes ($ 120 per individual) associated with the low detection probabilities makes this group inappropriate for short-term studies. Alternatively we suggest that environmental impact assessments are focused on taxonomic groups that simultaneously reflect robust diversity measures and are relatively easy to obtain samples. The remaining chapters of this thesis result from sampling surveys along nine years of monitoring snakes in standardized sampling units. In the Chapter II we tested the effects of ecological gradients of tree density, altitude and soil clay content on measures of taxonomic, functional and phylogenetic β-diversity. We show that the three gradients tested act as filters on the taxonomic diversity, which creates regional patterns of co-occurring species. However, differences in functional traits and phylogenies among sampling units are randomly distributed throughout the landscape, regardless of variation in the gradients tested. In the Chapter III we used thousands of genetic loci (SNPs) to compare patterns of gene flow between two ambush predator snakes and two active foragers. We show that the lower dispersal capability in ambush predators generates genetic differentiation among individuals and reduces the gene flow through isolation by geographic distance and environmental resistance. The active foragers, in turn, have high levels of gene flow over about 880 km of an heterogeneous landscape, and no evidence of genetic structure was found, regardless of the geographic distance and environmental resistance. We expect that the chapters of this thesis are part of integrative studies on biodiversity in the Amazon, which have been conducted through standardized sampling of different groups of animals and plants.