Chuva e banco de sementes em fragmento de floresta ombrófila densa, São Lourenço da Mata - PE, Brasil

Abstract

The rain and seed bank are fundamental natural regeneration mechanisms to restore the ecological functions of forest fragments and degraded areas. Thus, the aim of this study was to evaluate the rain and seed bank in the soil in a fragment of the Atlantic rain forest, located in São Lourenço da Mata – PE. The individual trees, identified by diaspores collected in rain seeds and the seedlings emerged in seed banks were recorded and classified according to dispersion and successional group syndrome. Sampling of banks and seed rain was performed in 60 existing plots within the fragment. For sampling of seed rain, were allocated 60 collectors (area of 0.196 m²) in the center of each plot, being equidistant about 50m. Samples were collected at intervals of 30 days for a period of 12 months. The seed bank in the soil was evaluated in the nursery and in the forest fragment. To evaluate the seed bank in forest nursery were taken from the center of each plot a soil sample, 50 cm x 50 cm x 5 cm. The samples were identified and taken to the forest nursery of the Rural Federal University of Pernambuco and put in wooden boxes, half of the samples were covered by 70% shade and half were exposed to the sun. To characterize the seed bank in the soil within the forest fragment were allocated subplots next to the site of the removal of soil samples, totaling 60 subplots of 0,25 m² each. In the rain, they were accounted for 124.878 seeds (10.619 seeds/m²) belonging to 60 morphospecies and 19 botanical families. Euphorbiaceae, Moraceae, Fabaceae and Melastomataceae showed greater wealth. Melastomataceae species presented larger seed density values. The predominant ecological group was early secondary species followed by late secondary. The seed bank emerged 3,965 seedlings of tree species (264,33 seeds/m²) belonging to 15 botanical families. In sombrite 70%, were accounted 3.441 seedlings, identified 14 families and 29 morphospecies. Already in full sun were accounted for 523 seedlings, 12 families and 19 morphospecies and families with the greatest richness were Fabaceae and Melastomataceae. The species that predominated were Cecropia pachystachya and Miconia prasina (full sun and 70% shading). The predominant ecological group was early secondary species followed the pioneers. For the seed bank evaluated within the fragment, were accounted 122 seedlings emerged, five families and 10 morphospecies, and Tapirira guianensis with more seedlings. There was a predominance of early secondary. The zoochorous dispersion syndrome predominated for rain and seed banks. Considering the regeneration mechanism evaluated, rain and seed banks, it can be concluded that the forest of Camurim fragment has a self-regeneration capacity by an environmental change.