Causes and processes determining the structure of anuran assemblage in an Atlantic Forest fragmented area

Abstract

Understanding causes and processes behind differences in species composition between areas can be useful in understanding how the degradation of natural environments affects the structure of communities. Beta diversity can explain changes between communities by partitioning two components: nestedness and turnover. In addition, it is to being a tool to infer about the role of deterministic and stochastic processes in determining community structure along ecological gradients. In this thesis, we evaluated in the Chapter 1 the importance of the two beta diversity components (nestedness and turnover) between continuous forest patches, forest fragments and pasture matrix; in the Chapter 2, we assessed whether the differences in communities obey deterministic or stochastic patterns in this local fragmented landscape in the state of RJ. We found that habitat amount region mediates the strength of nestedness and turnover, but their relative importance relevance depends on which type of environments are being considered in the comparison. We also observed the prevalence of stochastic processes driving the difference in species composition between forest fragments and matrix pastures. These results highlight the importance of evaluating which mechanisms are generating beta diversity patterns and the need of considering a gradient of land cover (including matrix areas) in biodiversity analysis to have a better understanding on biodiversity patterns in fragmented landscapes.