Evolução das tolerâncias climáticas em leguminosas arbóreas neotropicais

Abstract

The neotropical region has a high diversity of vascular plant that is correlated with many variables, such as with the climatic factors. Changes in the ecosystem can facilitate ecological opportunity and promote adaptive radiation. However, some clades do not radiate when in an apparent ecological opportunity, some lineages maintain their niches unchanged overtime or can converge to similar niches. This research evaluates the evolution of climatic tolerances of an line of arboreal plants in the Leguminosae family, specifically from the Bowdichia clade, part of the great clade Genistoide, from the Papilionoideae subfamily. In order to characterize the evolution of the climate niche in the Bowdichia clade, we gathered records of the species geographic distributions in national and international online databases, we performed phylogenetic analyzes and molecular dating, we built ecological niche models, we calculated niche overlap indexes, we produced Predicted Niche Occupancy (PNO) in a phylogenetic context, and estimated climate disparity over time. As results, high values of overlap between certain species of distinct subclades have been evidenced, higher values than expected by Brownian motion between others closely related, and low values of overlap between some species of the same subclade. Heterogeneity in the occupation of each bioclimatic variable between species was evidenced by the PNOs, and, taking into account the phylogenetic context, species radiation, over time, occurred over a wide range of spaces and bioclimatic conditions, showing events of niche convergence, divergence and conservatism. Furthermore, with regards to the disparity over time, it is suggested that the evolution of the clade occurred under gradual and late diversification events, instead of under a fast adaptive radiation through ecological opportunity in a moment prior to the clade irradiation. It is also suggested that divergent evolution has been favored in the Plio-Pleistocene with the rise of ecological opportunities after glacial and interglacial events beyond the Andes uplift of the consequences.