Conservação da biodiversidade vegetal do cerrado marginal do nordeste brasileiro

Abstract

The demarcation of protected areas has historically been the main biodiversity conservation strategy in the world. One strategy to drive conservation towards ecological processes is to add evolutionary and functional information from the organisms that make up the local assemblage. We investigated what is effectively conserved in the Cerrado Marginal of Northeast Brazil (NC), a biogeographical district that is part of one of the world's biodiversity hotspots. For this, we performed comparisons between the flora of angiosperms from different areas of the NC and the flora from other areas of the NC from a phylogenetic approach. In Chapter 1, we compare local assemblages based on taxonomic (∆+) and phylogenetic (PD, MPD, MNTD, and VPD) diversity indices. In Chapter 2 we investigated how plant phylogenetic diversity (phylobetadiversity) is distributed in the NC and what environmental factors influence this distribution. We recorded 1107 species for the NC. PD and MNTD indices were positively and negatively correlated with species richness (SR), respectively. MPD and ∆+ showed low correlation with SR, while for VPD no correlation was observed. We observed that, although it has the highest SR analyzed, the flora of PARNA Sete Cidades is mainly composed of species that have recently diverged, not necessarily associated with greater conservation of evolutionary history. Our results showed that the NC has a floristic similarity gradient that starts from the areas closer to the center of the domain towards its edges, however, when we consider the evolutionary dimension, this pattern is not repeated. Environmental factors related to water availability and temperature demonstrate the influence of the semi-arid climate on the NC. Thus, the demarcation of protected areas using only the dimension of species richness leads to the conservation of similar evolutionary histories. Therefore, looking for areas with phylogenetically distinct assemblages would contribute to the strategic planning of biodiversity conservation in the NC. Still, in the context of environmental changes, they reinforce the need for urgency in this change of perspective, since the semi-arid environments, which directly influence the NC, tend to be the most affected.