Densidade do banco de sementes em ambientes de interior e borda de floresta estacional semidecidual na Reserva Biológica Municipal Santa Cândida em Juiz de Fora, Minas Gerais

Abstract

The density of seed bank on the interior and edge parts in the forest of Municipal Santa Cândida Biological Reserve was evaluated through to germination method. The study area is an urban forestry fragment (113 ha) with troubled parts and other ones on succession advanced state. The collections were made during the months of July (40 portions) and December (60 portions), in 2005, and in October, 2006 (70 portions). These portions were used to phytosociological study. In each portion was made a sample composed by 3 points, it was made a gabarito of 11 x 11 x 3 cm. The result was 0,0363m2 for each portion. Ground and litter samples were analyzed separately. The ground volume corresponded to 3 cm of the surface and the litter volume corresponded to what was available on the marked out surface. The samples were smoothed, divided into the same parts and submitted to three different treatments: constant temperature of 30ºC and photoperiod of 12 hours (TCG), variable temperature (30º/ 20ºC) and photoperiod of 16 hours (TVL), nursery with light shade (SCC), nursery with moderate shade (SCS) and green house with moderate shade (SCES). Throughout these three collections was observed the density of 362,3 (+267,8), 431,58 (+-303,03) and 570,24 (+-333,7) seeds/m2. In general, there was not difference between ground samples of seed density from the interior and edge parts. Most of ground samples presented hardier density than the litter ones. Among the treatments there were more seedlings under nursery with moderate shade (SCS) than under nursery with light shade (SCC) and under laboratory conditions the temperature variation was more effective than constant. Melastomataceae, Poaceae, Cecropia spp and an undetermined climber were the more abundant rate. Except for a part of the edge much effected, the others present seed banks which give to the forests the capacity of regeneration. They can be used as a source of seeds in order to regenerated degraded areas, mainly of the own reserve.