Gradientes ambientais como estruturadores da diversidade filogenética e funcional de assembleias de pequenos mamíferos na Bacia Amazônica

Abstract

The community of non-flying small mammals is composed of marsupials and small rodents and its structure may suffer from ecological and historical factors. We compiled inventories of small mammals in the Amazon Basin and functional traits of the species sampled to evaluate the phylogenetic and functional structure of the assemblies. We also evaluated whether functional dispersion and species substitution at assemblies respond to environmental variables. We calculated the phylogenetic and functional diversity to access the structuring patterns of assemblies; we measured the functional dispersion to evaluate the effect of the environment on the functional traits; and we calculated the species substitution, decomposed into the effect of the composition and phylogenetic relationships during substitution, and related it to the environment. The phylogenetic structure of the assemblies was more dispersed than expected at random. There was little variation in functional diversity, with most assemblies more dispersed than expected by chance. The functional dispersion responded to the mean temperature of the warmest quarter probably due to the temperature relation with the physiological performance of the animals; and precipitation of the wettest quarter, which is associated with food availability. The substitution of the species responded to the environmental variables sum of soil bases, mean temperature of the warmest quarter and productivity. The compositional component of species substitution responded to the sum of soil bases, precipitation and geographic distance, while the phylogenetic component responded to the sum of soil bases and productivity. In general, the results suggest a greater weight of the phylogenetic relationships between the species not shared between the assemblies, than between the taxonomic composition of the shared species for the substitution of the species. The community of non-flying small mammals in the Amazon Basin does not happen randomly and is a response to evolutionary history and diversification of the group, and the environment.