The soil seed bank as an indicator of altitudinal gradient in a montane tropical forest

Abstract

The study was conducted in a portion of tropical montane forest in the Caparaó National Park, Brazil. The aim of this work was to assess the changes in seed bank composition, density and richness along an altitudinal gradient and across seasons, and to analyse the floristic links between the forest soil seed bank, seed rain, regeneration layer and adult tree layer. The seed bank data were collected in the dry and rainy seasons at seven different elevations, ranging from 1112 – 1550 m above sea level. The floristic relationships were analysed through the species lists derived from previous studies at these same locations. The results showed seed density and species richness varied among different elevations, but did not vary with gradient. Seed bank density and richness varied significantly across seasons, with the highest averages found in the rainy season. In the floristic composition, the higher elevations showed more similar composition than to the lower elevations. Seed bank composition was floristically different from the seed rain, the regeneration layer and the adult tree layer of the forest. Our results showed that the soil seed bank was influenced by both altitude and environmental seasonality. The findings highlighted the importance soil seed bank as a mechanism of post-disturbance forest regeneration.