Dinâmica da vegetação de um fragmento de mata atlântica nordestina.

Abstract

Data are presented for 2004, 2007 and 2010 on physiognomy, dynamics, diversity, species composition and density of the wood plant canopy (CA with CBH> 15 cm) and understory (UN, with a circumference at ground level between > 3cm and CAP <15cm) in a gradient edge-interior formed at 35 years in an Atlantic Forest fragment, Igarassu, PE. In 2004, three environments were evaluated: edge (0-50m), intermediate (50-100m) and interior (more than 150m from the tree line), and analyzed by environment of 1000 m², divided into plots of 10 × 10m, to measure the CA individuals. In each plot was plotted a subplot of 5 × 5m for the UN sample. In 2010 branches were collected from three adult individuals of the species for the collection of sample disks. The number of individuals (NI), basal area (BA) and demographic rates in the three environments the CA showed no edge effect or if there was, since the edge is sealed. In UN the edge had lower values of NI and BA demographic rates and higher than the inside. Differences between strata occur, regardless of sealing the border, as the young plants that are still in UN are more sensitive than the trees of the CA, the changes caused by the creation of the border. Rates of loss and gain of BA and BA rotation in NI and UN showed higher values than in the CA, which points to a stratum with major changes. In CA there were no differences in species richness between environments, distinct from that observed in UN. The composition in CA environments closer to the tree line were very similar and distinct from the interior, indicating that there has been no recovery in all environments while the composition of the UN had low similarity. The edges of CA and UN showed higher concentration of individuals at intervals of class values lower density wood. It can be concluded that the CA has regained biomass, although the edge and have not recovered to intermediate composition. The UN also suffer from edge effect. If we consider that the environment had more edge classes of individuals in wood density of less value and that there is an inverse relationship between wood density and mortality rates / annual periodic increment in diameter can be assumed that the different composition of the edge would be result of the increased mortality of species of lower density wood.