Variação espaço-temporal do banco de sementes do solo de duas florestas de restinga do Nordeste do Brasil

Abstract

The soil seed bank reflects important information about the establishment of populations, maintaining the diversity and richness of restoration before anthropogenic or natural changes in plant communities of tropical rainforests from analyzes of spatial and temporal variations in the stock of seeds formed in system. Whereas climatic conditions associated with different landforms resulting from geologic formations, are factors that influence the formation of various ecosystems, and consequently, the formation vegetables that compose them with or without the influence of the chemical composition of the soil in the establishment of vegetation, geomorphologically areas with different climatic conditions, topography and floristic different influences, present different strategies for recruitment, establishment and maintenance of diversity. Thus, this study aimed to examine the dynamics of the soil seed bank of two Restinga forests of northeastern Brazil. Were selected for this study two forests Restinga, one located in Porto Seguro - BA in Wildlife Refuge Rio Friars (Friars Rio Revis) and one located in the municipality of Luiz Correia - PI, which includes the Environmental Protection Area Delta Parnaíba. The sandbanks are allocated to distinct geomorphological boundaries, in northeastern Brazil. In order to verify whether there are differences between areas in relation to density, richness and germination period individuals were collected 50 soil samples (20 x 20 x 5 cm) over five transects of 100 m, in the rainy and Dry each area. The samples were placed in trays for monitoring greenhouse and observed daily for six months in each seasonal period. Individuals from both areas showed more intense germination (60 to 70% of individuals germinated in the experiment) in the first 60 days of observation. In total 1106 individuals germinated in samples of Bahia, distributed in 19 families, 21 genera and 21 species. In samples of Piauí the germinating totaled 1,357, distributed in 24 families, 34 genera and 39 species. Piauí showed greater wealth specifies that Bahia, and greater species richness and seed density in the collections of the dry period (P <0.0001). The floristic composition of the areas was significantly different (p = 0.001) and 30% of the group formed in the analysis of similarity (ANOSIM), is explained by environmental characteristics of plant communities analyzed. The soil is of sandy shoals, completely randomized design, and the significant difference shown by chemical analysis (Ca, Mg, Na, K, Al, P, and interactions between them) showed the characteristics that differentiate the two areas for the levels of these components.