Banco de sementes do solo pós-fogo em um mosaico vegetacional no Domínio Atlântico

Abstract

Some disturbances, such as fire, can interfere in the dynamics of tree communities, compromising the biodiversity and maintenance of ecological processes. In other cases, fires can stimulate seed bank by favoring some species that evolved with fire as a selection factor. In September of 2011, there was a fire that reached a large portion of the area of a vegetation mosaic in the municipality of Lavras, Minas Gerais, Brazil. In this context, the objective of this thesis was to understand the post-fire ecological response of different environments, by means of the temporal monitoring of species richness, density, frequency and abundance of seedlings in the soil seed bank. The study location was the private area of the Parque Ecológico Quedas do Rio Bonito, with vegetation characteristic of the Atlantic Domain. We collected soil samples in October of 2011, April and October of 2012 and April and October of 2013, in 66 points distributed in eight environments with different traits. A total of 11.458 seedlings emerged. Species richness in most environments was higher in the samplings performed in October and lower in April, indicating that the seasonality affected the seed bank. The rarefaction curve showed that the species richness of the seed bank did not stabilize and that the number of species per area is increasing at each sampling. The highest values of density and frequency of the seed bank were characterized by species adapted to fire or species able to break dormancy with the influence of fire. In general, the number species increased during the observation period, demonstrating that the studied environments are in initial stages of ecological succession after the fire.