Niche shifts among woody formations in eastern South America

Abstract

Niche conservatism, that is the retention of ecological traits over time, is both a pattern and process with wide ecological relevance. This conservatism may influence several descriptors of vegetation like its diversity, the ability of species to modify their range and, therefore, the resilience of the vegetation. Our aims are to identify the extent of niche conservatism among woody formations in eastern South America, by means of the evaluation of their phylogenetic structure, the rate of niche changes and the diversification of different taxonomic levels, and by the identification of main drivers of the rates of diversification. These aims can be achieved by the availability of huge databases for species distribution and by phylogenetic analyses currently developed. Firstly, we will quantify the number of woody formations occupied by each taxon, the phylogenetic signal for this quantity and the fit of the observed values to different evolutionary models as indicators of niche shifts. In addition, we will test if formations which are similar in climate show taxonomic convergence and if the phylogenetic clustering estimates are related to climatic variables. After that, we will evaluate the direction of species' niche shifts among formations to decide whether it occurs mainly to similar climatic formations or elsewhere. Finally, we will quantify the rates of diversification along all taxonomic levels, which will be then tested for correlations with environmental conditions from each formation. With these results, we intend to better understand the ecological structure of woody formations and help to develop strategies for their conservation.