Efeito de borda sobre a fenologia, as sÃndromes de polinizaÃÃo e a dispersÃo de sementes de uma comunidade arbÃrea na Floresta AtlÃntica ao norte do Rio SÃo Francisco

AUTOR(ES)

Patricia Araujo de Abreu Cara

DATA DE PUBLICAÇÃO

2006

RESUMO

Background and aims The high plant species richness and the pollination mechanisms in the tropical forests are endangered by the loss of ecological groups, consequence of the forest fragmentation. The objective of this study was to evaluate the edge effect on the pollination and the reproductive systems of a tree community. Methods 600 tree individuals belonging to 95 species (77 genera and 41 families) were studied during two years in the largest northeast Brazilian Atlantic Rainforest fragment (3.375 ha, Alagoas State) in the edge and interior (top and valley) environment. By means of direct observations of floral attributes, literature and herbarium material the pollinator guild, reproductive systems and floral attributes like colour, size, flower type and offered resource were examined. The floral attributes, the reproductive systems and the pollinator guild were compared regarding the number of individuals and species, respectively, for the three sampled environments. Key results Entomophily predominated in the three habitats, emphasizing mellitophily, followed by pollination by diverse small insects. After entomophily, chiropterophily and ornithophily were the most frequent pollination syndromes. The hermaphroditic reproductive system dominated, with the majority of the species showing small inconspicuous flowers of light colours and offering nectar or pollen as resource. The percentage of individuals in each ecological attribute differed significantly between the environments. There was a significant difference between the habitats on the number of individuals in the flower attribute classes, pollinator guilds and reproductive systems, as also on some relations between reproductive systems, floral attributes and stratification vs. pollinator guilds. Conclusions The edge effect is influencing the pollination systems via changing the species composition favouring populations of more generalistic pollination systems and hermaphroditic sexual expression, which could be pollinated for many pollen vectors

ASSUNTO(S)

anatomia vegetal sistemas sexuais borda polinizaÃÃo zoofilia community zoophily fragmentaÃÃo floresta atlÃntica comunidade edge atlantic rainforest entomofilia entomophily pollination sexual systems fragmentation

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