Spatial patterns of terrestrial vertebrate species richness in the brazilian cerrado

Abstract

In this paper, we used a“deconstruction”approach to evaluate the spatial patterns of species richness of terrestrial vertebrates in the Brazilian Cerrado. Six environmental variables as well as the human population size and number of inventories were used as predictors of species richness (the last 2 to account for variable sampling efforts). Moran,s I coefficients revealed strong spatial autocorrelations in ordinary least-squares multiple regression residuals, and thus spatial filtering by eigenfunction maps, based on a Gabriel network for the Cerrrado grid system, was used to evaluate the influence of richness predictors, thereby minimizing statistical problems caused by spatial autocorrelations. Models generated for the species richness of each group were compared and showed that spatial patterns of richness for all groups tended to be relatively well explained by climatic variations, in terms of the energy-water balance. Effects of productivity also appeared as a secondary effect for all groups but mammals. Richness patterns in amphibians and reptiles may have been biased by a lack of precise faunal knowledge, although they were not explained by the usual surrogates of the human population size and number of inventories.