Regeneração natural em diferentes ambientes da mata de galeria do Capetinga, na fazenda Água Limpa-DF

Abstract

The Capetinga gallery forest is located at Agua Limpa Farm, in the Federal District, Brazil. The floristic composition and structure of the natural regeneration at the edges and in the interior of the gallery forest at the watershed of the Capetinga stream was studied to detect floristic and structural patterns related to the forest environments. Thirty (5x5m) plots were placed in each environment to sample saplings, individuals from 1,0m high with diameter at the steam base under 5,0cm. Within these plots, (2x2m) sub-plots were allocated to sample seedlings, individuals lower than 1,0m height. The sampled plots were distant to the stream bank to minimize the humidity effect. Shannon & Wiener diversity index varied from 2,86(seedlings at the edges) to 3,51 (saplings at the interior) and it was higher in the interior for both categories. Sørensen’s similarity index varied from 0.474 for seedlings (comparing edges with interior) to 0.735 (seedlings and saplings at the edges). Czekanowski indices were low and reflected the high differentiation in structure from plot to plot in the same gallery forest. TWINSPAN classification suggested two distinct communities for saplings for both conditions, formed by species accordingly to their requirements for light and water. No differentiation was detected for seedlings between the environments indicating a low response of plants at an early stage to the environmental conditions within the forest. The Capetinga gallery forest suffered disturbances by fire and the small variations in species composition and vegetation structure between environments suggests that most of the natural regeneration is tolerant to light.