Florestas montanas em gradientes altitudinais da Mata Atlântica: ecologia e conservação

Abstract

The Atlantic Forest domain is an important biodiversity conservation hotspot due to its high species diversity and the presence of threatened and endemic species. Despite its high importance, this phytogeographical domain is currently reduced to approximately 14% of its original extent. Inserted in the Atlantic Forest, there is one of the most important areas in the world for biodiversity conservation, the Mantiqueira Range. This mountain range, due to its large altitudinal variation and the extensive stretches covered by forest, constitutes a promising area for studies of forest ecology. With the development of tools that evaluate the phylogenetic structure of communities, and methods for the creation of supertrees, communities can be evaluated through an evolutionary perspective, enabling to evaluate the ecological processes that structure communities. The use of tools that evaluate the phylogenetic structure of communities along altitudinal gradients inserted in the Atlantic Forest domain and in the Mantiqueira Range can be useful for the evaluation of the factors that govern tree communities of these important areas for conservation and can thus assess the effects of changing environmental conditions on forests, including the effects of global climate change. In this context, the present work aimed to evaluate the influence of altitude on tree communities in Mantiqueira Range, southeastern Brazil, through tools that evaluate the tree structure and the phylogenetic structure of communities, aiming to evaluate the processes that govern the communities and the environmental changes effects on these communities. This thesis was divided into two parts. The Part 1 consists of a brief review on themes that comprise the following two chapters: the Atlantic Forest domain, Mantiqueira Range, influences of altitudinal gradients on forests, and phylogenetic structure of communities. The Part 2 is composed of two scientific articles. In the Article 1, the influences of altitude, temperature, and soil conditions on the phylogenetic structure of four tree communities of Upper Montane Atlantic Forest were evaluated along an altitudinal gradient (1500 m to 2100 m) in the Mantiqueira Range, southeastern Brazil. High phylogenetic lineage turnover was observed among the communities along the gradient, with this high turnover being correlated with the decrease in temperature and variations in soil conditions. It has been shown that phylogenetic lineages can be lost in the face of global climate change. In the Article 2, the influence of altitude on tree structure and phylogenetic structure of nine Tropical Montane Cloud Forest communities were evaluated along an altitudinal gradient (1210 m to 2320 m) in Mantiqueira Range, southeastern Brazil. Were observed correlations of altitude with species richness and phylogenetic structure of the communities, with a tendency of increasing phylogenetic clustering with altitude increase. This decrease in phylogenetic lineages with elevation indicates that the evaluated communities, especially those of higher altitude, have a low capacity to adapt to global climate change.