A vegetação das dunas costeiras do litoral nordestino: riqueza, composição, fatores ambientais e impactos antrópicos

Abstract

The vegetation that establishes itself in the coastal dunes is responsible for the static condition of the sediments and maintenance of biodiversity. However, human activities aimed at urbanization and tourism mischaracterize the ecosystem. In view of this, conservation strategies have been sought that unite the socioeconomic use and the maintenance of the ecological processes of this ecosystem. In Brazil, the dunes are mainly present on the northeastern coast. Geographical and oceanographic factors made it possible to divide the Northeast into two areas; the Northern Northeastern Coast (LNS), which covers the states of Maranhão to Ceará and part of Rio Grande do Norte and on the other side, the Eastern Northeastern Coast (LNO) which concentrates from the rest of Rio Grande Norte to Bahia. Although there is information about the region's vegetation, these data are few if we consider the entire territorial extension. Thus, our objective is to investigate the richness and composition of the vegetation of coastal dunes in the northeast region, to indicate the floristic relationships of the woody plants of the dunes with the neighboring phytogeographical domains and to correlate which bioclimatic and geographic variables act as environmental filters of the dune vegetation, in regional scale. Considering the aforementioned information, in this thesis, we tested the following hypotheses: The plant diversity of the Northeast coastal dunes presents different forms of life and indicator species. The dunes on the eastern coast have a different richness and plant composition than the dunes on the northern coast due to differences in floristic relationships. On a regional scale, the richness and composition of coastal dunes are directly related to bioclimatic factors due to geographic differences in the region. The thesis is divided into two chapters. In the first chapter we present an overview of plant richness and composition, with a list of species, life forms and origin, we carry out a similarity analysis and provide information on public policies for the conservation of coastal dunes. In the second chapter, we investigate the relationship between woody vegetation of coastal dunes and neighboring phytogeographic domains and correlate bioclimatic and geographic factors. We performed a Principal Component Analysis and found that the differences between the northern and eastern coasts are determined by rainfall patterns. Upon concluding this thesis, we were able to corroborate the proposed hypotheses, demonstrating that the distinction between the vegetation of the LNS and LNO. We concluded the thesis, demonstrating differences between the vegetation of the LNS and showing the vegetal diversity of the coastal dunes of the Northeast, Brazil.