Functional Diversity and Assembly Rules of Two Deciduous Seasonal Forests in Southeastern Brazil

Abstract

Deciduous seasonal forests (DSFs) have a peculiar floristic composition, with species capable of surviving periods of high water deficit in a year. Our goal was to demonstrate that abiotic filters lead to the assembly of two DSF communities that have high floristic dissimilarity. For this, we characterized the environment of the areas and used the community-weighted mean (CWM), functional richness (FRic) and functional dispersion (FDis) indices for regional recognition of functional patterns. The local assessment of assembly rules was carried out using null models. We found differences in the FRic and FDis between the areas, which was attributed to the different floristic influences exercised on the communities. However, in both, the typical attributes of dry formations were dominant (CWM), indicating that, on the regional scale of study, the dry season acts as a filter in the composition of species in the communities. On a local scale, stochastic dispersion was identified as the most influential mechanism in the assembly of communities. We conclude that deterministic and stochastic processes act in the assembly of the studied communities, and the proportion of each of these depends on the scale, with abiotic filtration predominating on a regional scale and stochastic dispersion events on a local scale.

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