Floristic Relationships of Seasonally Dry Forests of Eastern South America Based on Tree Species Distribution Patterns

Abstract

The tree flora of seasonally dry forests (SDTF) of eastern tropical and subtropical South America was investigated according to two main aspects: (a) the variations in floristic composition were analyzed in terms of geographical and climatic variables by performing multivariate analyses on 532 existing floristic checklists; and (b) the links among different seasonally dry forest formations, Amazonian forests and cerrados (woody savannas) were assessed. Analyses were performed at the species, genus and family levels. There was a strong spatial pattern in tree species distribution that only receded and allowed clearer climate-related patterns to arise when either the geographical range was restricted or data were treated at the genus and family levels. Consistent floristic differences occurred between rain and seasonal forests, although these were obscured by strong regional similarities which made the two foresttypes from the same region closer to each other floristically than they were to their equivalents in different regions. Atlantic rain and seasonal forests