Colonização de ambientes abertos do cerrado por espécies arbóreas florestais: a ação facilitadora de Bowdichia virgilioides Kunth

Abstract

This thesis deals about the study of a colonizing forest tree species community in Bowdichia virgilioides nuclei in a cerrado sentido restrito area (savannic formation) at Estação Ecológica do Panga (Panga Ecological Station). The study was contextualized, in general introduction, outlining the main theoretical concepts discussed and Estação Ecológica do Panga situation, which made this place suitable for such study. Then we presented general descriptions, location, and environmental and vegetation characteristics of study site, in material and general methods section. After this description, thesis was divided into two chapters. First chapter aimed to characterize colonizing tree forest community below B. virgilioides crown in cerrado sentido restrito. For this aim we used floristic composition, nuclei structure (number of species and individuals and size characteristics of each nucleus), colonizing species grouping of different colonization stages, and nuclei classification in colonization stage by proportion of individuals of each group in the nucleus. In the second chapter the aim was to describe morphological leaves characteristics of the main species colonizing the nuclei, testing differences between mean specific leaf area and internodes between individuals of the same species in nuclei and in forest environment. In addition, we sought a relationship between main colonizing species nuclei coverage value index and specific leaf area in forest. The results showed that species that highlighted in nuclei colonization were: Tapirira guianensis, Symplocos pubescens, Styrax camporum, Ocotea corymbosa, Cardiopetalum calophyllum, Ocotea minarum, Rudgea viburnoides, and Myrcia splendens. Colonization is influenced by the presence of adults and their dispersal agents in adjacent forest formation, nuclei distance from this formation edge, nucleator individual area of influence, and ecological colonization characteristics of each species. Species highlighted in colonization also showed to have acclimation capacity to survive in an enlightened environment. This capacity was detected by differences between mean specific leaf area and internode distance of individuals in nuclei and in forest formation.