Functional convergence in the structure of fish assemblages in two watersheds streams in São Paulo

Abstract

Functional convergence between isolated ecosystems suggests the existence of common mechanisms underlying the organization and dynamics of ecological communities. Evidences of functional convergence revealed by similar responses functional traits assemblies to the same environmental factors, suggest large-scale effects that are transferable between different ecoregions. In this project, we will test the hypothesis that functional traits related to the use of habitat, trophic ecology and life history of fish assemblages are related to the structure of aquatic habitats, and that this relationship is convergent between the basins of the Itanhaém river basin (southeastern coast basin) and the High Paranapanema (Paraná basin). These basins arbor biogeographically isolated faunas but their streams have similar habitat structures. Fish samples will be done with electrofishing equipment, along the longitudinal gradient in each basin. The fishes will be identified, weighed and obtained morphological measures related to habitat use, life history and trophic ecology. The hypothesis of association between the functional traits and habitat structure will be tested by means of the RLQ analysis and the relationship between functional diversity and habitat structure by a redundancy analysis (RDA). Functional convergence will be tested by analyses of covariance models (ANCOVA), evaluating the effects of river basin and habitat structure on the functional traits and functional diversity indices. (AU)