Influência da topografia e da abertura do dossel na estrutura do componente herbáceo-arbustivo em dois fragmentos florestais na planície de inundação do alto rio Paraná

Abstract

Secondary forest area enlarged significantly in the recent years. Due to the importance that this kind of forest has taken regarding plans for restoration and conservation, a wider understanding of its organization and functioning, considering the different life forms is necessary. Aiming at comparing the composition and structure of the herb-shrub component between two forest areas at different stages of recovery (RFID-forest remnant and FLT- 57-year old forest), as well as the relative influence of the topography and canopy opening on the organization of the community, vegetation and environmental data were collected on 24 contiguous plots in each site. Moran’s I correlograms and partial Mantel tests were used to test for correlations between community data and environmental variables. To examine differences between sample areas, Student’s t-tests were applied. The lianas proved to be spatially structured in both environments, with a trend similar to that observed in the average elevation. In RFID, average elevation distances were positively correlated with the distances of tree density and total richness matrices and negatively correlated with the distance matrix density of herbaceous plants. In FLT, significant correlations were observed only between the distances of the tree density matrix and those of maximum elevation difference and between distances of elevation and those of total species richness. By comparing the two areas, only the shrub components and to canopy opening did not presented differences. The structure of the herbaceous shrub component was associated with topographic characteristics, suggesting a strong influence of the flooding regime.