Fatores que influenciam a diversidade Beta de anfíbios da Mata Atlântica

Abstract

The distribution and abundance of species vary across regions and can be shaped by environmental gradients. Thus, understanding how environmental changes affect assemblage composition is essential in predicting biodiversity responses under climate change. This challenge becomes particularly relevant in the Atlantic Forest, one of the most biodiverse regions on the planet and home to one of the most threatened amphibian faunas in the world. In this context, this study investigated how amphibian species composition varies along environmental gradients within this biome, identifying the most influential contemporary factors. To achieve this, we compiled amphibian inventories available in the literature and combined them with bioclimatic, edaphic, and topographic variables, using generalized dissimilarity modeling (GDM). This approach allowed us to evaluate how environmental factors influence the taxonomic, functional, and phylogenetic beta diversity of Atlantic Forest amphibians and to identify regions most susceptible to changes in species composition, functional traits, and phylogenetic lineages. Despite the heterogeneity in taxonomic composition among assemblages, we observed that they occupy similar regions in functional space, indicating ecological redundancy among species. This impression was further reinforced by the strong correlation between functional and phylogenetic diversity, suggesting that the evolutionary history of amphibians may have shaped their ecological roles. Predictably, most observed changes in composition occur among closely related species. Environmental factors such as geographic distance, isothermality, and clay content in soil emerged as major determinants across all three dimensions of beta diversity, while other predictors, including silt content in soil and precipitation of wettest month, showed additional effects. Our results also revealed a latitudinal differentiation gradient, indicating that regions in the south, as well as the northeastern coast and interior of the Atlantic Forest, will be more susceptible to substantial shifts under future climate scenarios. These patterns highlight the role of historical climate stability and edaphic characteristics in shaping species composition, evolutionary lineages, and functional traits. The ecological redundancy observed among Atlantic Forest amphibians may represent a mechanism of resilience in the face of climate change, although its effectiveness likely depends on how these patterns are distributed regionally and how individual species respond to environmental alterations. Finally, our findings highlight the importance of macroecological approaches in guiding conservation strategies. Our study contributes to clarifying the ecological processes that have shaped, and continue to shape, the amphibians beta diversity in the Atlantic Forest, a high conservation priority biome.