Publications (2)0 Total impact
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ABSTRACT: The Capetinga gallery forest is located at Agua Limpa Farm, in the Federal District, Brazil. The floristic compositionand 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 (comparingedges with interior) to 0.735 (seedlings and saplings at the edges). Czekanowski indices were low and reflected the high differentiationin structure from plot to plot in the same gallery forest. TWINSPAN classification suggested two distinct communities for saplings forboth conditions, formed by species accordingly to their requirements for light and water. No differentiation was detected for seedlingsbetween the environments indicating a low response of plants at an early stage to the environmental conditions within the forest. TheCapetinga gallery forest suffered disturbances by fire and the small variations in species composition and vegetation structurebetween environments suggests that most of the natural regeneration is tolerant to light.
Cerne. 01/2009;
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ABSTRACT: An analysis of the soil seedbank from the understory of Pinus and Eucalyptus in the Floresta Nacional de Brasília wasperformed, these plantations were established in the 1980s, and since 1987 have not had adequate management. Two stands of each genuswere chosen, with and without gaps. In each one of these stands 15 plots of 2 x 2 m were implanted, where a sample of 0,30 m x 0,30 mof soil and two sub-sample of 0,125 x 0,15 m of litter were collected for a quantative and qualitative analyzis of the seedbank. The mediumdensity of seedlings emergence in the Pinus stand was 3.098,19 seeds.m-2 while for the Eucalyptus it was of 2.077,19 seeds.m-2, whichmeans that the seedbank from the Pinus understory area has a higher regeneration potential than the Eucalyptus plantations. The Pinusplantations contained in the understorey: 12 families, 25 genus and 39 species, while in the Eucalyptus: 14 families, 31 genus and 48species, proving more richness in the Eucalyptus seedbank. In both genuses the most important families were Poaceae and Asteraceae.Both Pinus and Eucalyptus seedbanks populations, with or without openings, proved that the more interference in its population higheris the number of seeds from herbaceous species in comparison to tree species. The Sørensen similarity índex applied to analyze theseedbanks in the four areas, both for soil fractions and litter, was low, 0,5 and 0, 486, respectively.
Cerne. 01/2008;
