Conexões florísticas e funcionamento de comunidades arbóreas associadas à inselberg no domínio atlântico

Abstract

The present thesis is structured in two articles. The first aimed at unde4rstanding the phytogeographical relations of three tree communities associated to an inselberg in Minas Gerais, Brazil (Serra da Canoa), through the floristic analysis of 22 forest locations/units in different geographical scales of the same state, including three tree communities associated to another inselberg. We used two multivariate analysis techniques: distended correspondence analysis (DCA) and grouping analysis (dendrogram). The communities associated to the Serra da Canoa inselberg revealed a higher floristic affinity with the semideciduous stationary forests of the Campo das Vertentes and western Minas Gerais mesoregions. The inselbergs, both in the countryside, were located in ecotone regions between the Atlantic and Cerrado domains. However, this phytogeographical relation of ecological tension was more pronounced in the Serra da Canoa inselberg, evidenced by the forest islands, which presented floristic elements characteristic of open formations and of a larger climatic seasonality. In the second article, we evaluated the influence of environmental variations in the floristic and structural arrangement of three tree communities associated to the inselberg, and its correlations with the surrounding matrix, both sampled at the Serra da Canoa, Estação Ecológica Mata do Cedro, MG. The Serra da Canoa – Estação Ecológica Mata do Cedro is characterized by the high diversity of tree species, reflected by the environmental heterogeneity imposed by the inselberg. Soil depth and with water retention capacity were the main responsible, at a short distance, for the strong environmental gradient of species substitution and structural patterns between the investigated tree communities.