Vegetation structure and dynamics in a remnant of Atlantic Rainforest, Northeastern Brazil

Abstract

Edge effect produces a series of modifications on vegetation structure, microclimate, dynamics and species composition, making this environment very distinct from forest interior. In this study, the influence of distance from the forest border on the structure and dynamics (2006 and 2009) of canopy and understory assemblages was analyzed in a 14 ha fragment of Atlantic Rainforest in Igarassu, PE, Brazil. The edge, formed about 35 years ago, was defined
as area between the forest margins up to 50 m inwards; the intermediate environment was considered from 50 m to 100 m; and the interior environment beyond 150 m from the edge line. In order to sample the canopy (individuals with stem diameter ? 4.77 cm at 1.30 m from the ground) ten 10 × 10 m plots were allocated in each environment; for sampling the understory (individuals with stem diameter at ground level > 0.96 cm up to stem diameter at 1.30 m ? 4.77 cm) sub-plots of 5 × 5 m were located at the apex and the left side of the canopy plots. Density and basal area of canopy were similar along the  edge – interior gradient, whereas the understory had greater values in the interior. For the canopy, the edge showed the highest average increment in diameter and was the only environment to provide recruitment (absolute) higher than mortality. For the understory, in all environments, recruitment was greater than mortality. Distance from forest margins did not influence forest structure and dynamics.