Relationship between soil seed bank and canopy coverage in a mined area

Abstract

The objective of this study was to evaluate and correlate information about soil seed bank and canopy (%Canopy Openness and Leaf area index-LAI) in a mined area in restoration process through natural regeneration. The study area is located in Zona da Mata of Minas Gerais, which presents predominance of Semideciduous Seasonal Forest, and has an area of 0.5 ha in process of natural regeneration after six years of bauxite exploitation (without any intervention). Along the area, ten plots of 45x29cm were allocated and distributed in the best way to represent the whole area in restoration process. Seed bank diversity and canopy characteristics were evaluated in these plots, the last one using a NIKON D40X photographic camera, with fisheye lens of 8mm. As results, 8280 individuals (tree, shrub, herbs, and vines) were found, totaling 51 species and 24 botanical families. The Shannon diversity index (H’) was 2.770, and the equability (J) was 0.705, which demonstrate an average diversity in this area, with a density of 2114.94 germinated seeds m-2. Through the evaluation of the seed bank, the presence of exotic species (23.5%), the dominance of the pioneer species (68.6%), as well as high dispersal by wind (52.9%) were verified in the area. According to canopy characteristics, a significant variation between different points/regions within the study area was found, while patterns of existence of certain herbs as a function of canopy openness (lower vegetal cover/clearings) were also identified, as well as in response to spatial proximity between the allocated plots, confirming the high correlation between these two variables and their importance in the process of forest restoration.