Brejos de altitudes nordestinos face à mudanças climáticas: predições de distribuição como ferramenta para a gestão ambiental

Abstract

Global climate changes can drastically influence the distribution of global ecosystems, thereby affecting the flora and fauna composition by powering habitat loss, bioinvasion and extinction. Sensible ecosystems such as Montane and sub-Montane floras are priority for conservation. In this category are classified the brejos de altitude from Northeast Brazil. These ecosystems are characterized by a flora from Tropical humid Forest surrounded by a Semidecidual Tropical Dry Forest matrix, known as Caatinga. Tools such as the species distribution models turn out as a technological alternative to predict the climatic influences over the brejos de altitude flora. This work aimed to apply such methodology to verify the distribution predictions to the brejos de altitude for the years 2050 and 2070, by comparing it with an actual distribution model and conservation data available on specialized literature. To build each model, 24 distribution points from brejos areas were selected and evaluated by two analyses, the first considers the changes in temperature and precipitation, and a second consider only precipitation. For each analyses three models were built, one for the post industrial revolution time, one for the year 2050 and the last for 2070. Each model was evaluated with the AUC values (Area Under Curve). Our results suggest that the brejos de altitude flora tend to be more influenced by changes on the temperature and precipitation than only by precipitation. Forest fragments related to the Borborema Plateau present better conditions to have its flora maintained until the end of the century. Conservation unities located on brejos de altitude areas deserve special attention, especially the biological reserve of Serra Negra, due to its isolation and position westwards from the Borborema Plateau. Conservations strategies may be taken to avoid habitat loss and consequent local extinction in areas out of the Borborema Plateau, due to lower probabilities to maintain the brejos environment.