Macroecologia e conservação de múltiplas dimensões da biodiversidade

Abstract

Determining the mechanisms underlying spatial variation in biodiversity has long been the main challenge for ecologists and biogeographers. The past decade has seen a veritable explosion of studies documenting broad-scale spatial patterns in biodiversity. Nowadays, broad-scale patterns of species richness (SR) are well documented for several groups. However, biodiversity encompass variation in several aspects beyond SR, such as phylogenetic diversity (PD) and functional (or trait) diversity (FD). These dimensions have been argued to aid more powerful tests of biodiversity theories because they can capture the diversity of life better than simple measures of SR. Particularly important, the conservation of biodiversity and its multiple dimensions have been advocated as necessary to ensure the resilience of ecosystem services and maintain important evolutionary history. The present thesis is set on the interface between macroecology and biodiversity conservation, and uses integrated approaches that consider the connection between more than one dimension of biodiversity. In the first chapter, I we evaluate four prominent hypotheses which invoke either equilibrium (more individuals, niche diversity) or non-equilibrium dynamics (diversification rate, evolutionary time) to explain species richness and functional diversity of mammals worldwide. While equilibrium and non-equilibrium hypotheses have received considerable attention in the literature and some empirical support, it remains unknown whether they can explain the diversity of species and their traits alike. By integrating information on species richness and functional diversity, I address these issues and shed light on the mechanisms that generated the diversity of mammals and their life histories. The second chapter represents a database on natural history traits for amphibians worldwide: AmphiBIO. This database centralizes information on 19 traits related to ecology, morphology and reproduction features of amphibians. Data were assembled from more than 1,500 sources, and has potential to support a more comprehensive research in evolution, community ecology, biogeography and conservation of amphibians. The third chapter uses information from AmphiBIO to test the assumption that loss of PD is associated with loss of FD. We simulated species extinction scenarios based on IUCN criteria, calculated the loss of PD and FD, and verified the correlation. Analyzes were carried out across the complete amphibian tree and across worldwide amphibian assemblages. This study highlights for the possible negative consequences of local amphibians extinctions that may impact the continuous provision of ecosystem services. This thesis adds to better understand the mechanisms on the origination of global gradients of species diversity. Finally, I hope this thesis can be used to stimulate future studies on ecology and evolution, and support political decisions on minimizing the effects of projected species extinctions on biodiversity loss.