DinÃmica estrutural da comunidade arbÃrea de um fragmento de floresta semisecÃdua Ãs margens do Rio Capivari, Lavras/MG / Structural dynamics of arboreal community in a tropical semideciduous forest fragment at Capivari river border in Lavras, Minas Gerais.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

The aim of this study was to describe the arboreal community dynamics of a semideciduous seasonal forest fragment Capivari river border in Lavras, Minas Gerais. The forest fragment is known as Capivari forest. The study was divided in three parts: the first is a general description of the approached issues, (chapter 1); the second is about the changes in forest composition and community structure (chapter 2) and the third describes an arboreal community dynamics according to the demographic data of the individuals number, mortality rate, recruitment, change and turnover, and also, in relation to basal area, loss rates, gain, change and turnover, besides the distribution in diametric classes, it was also described, the dynamic of more abundant populations (chapter 3). In a period of six years, two surveys were done (1997 and 2003) of the arboreal compartment where all the individuals were measured with chest high diameter (DAP) ≥ 5 cm, in 28 parts of 20x20 m, placed in five transects. The analyses were done to the community as a whole and for each type of soil separately (Argissolo A, Argissolo B e Cambissolo) when necessary. Capivari forest presented an arboreal extract with similar diversity to other fragments of the region, with about 31% of the species were sampled with only one individual. It was confirmed the lost of five and the gain of three species. The diversity measured by Shannon index, and the distribution of the individuals in diameter classes showed unstable during the period. About the general dynamic, the recruitment and mortalily annual average rates for the whole community were 2,40%.year-1 e 2,20.year-1, what resulted in a turnover rate of 2,30%.year-1. Considering the basal area, the addition rate (1,90%.year-1) was less than the reducing rate (2,10%.year-1); the turnover rate was 2,00%.year-1 and the turnover time was 30,19 years. There is a relative stability in individuals number (3,32 years) and in basal area (4,17 years). The duplication time for basal area to whole community (36,83) was higher than the predicted in individuals number (31,85 years). The intensities of changes were very low, when we analyze Capivari arboreal community as a whole and also the three types of different soil separately. The mortality rate, recruitment and turnover were different only to Argissolo B in relation to the other soils and the community as a whole. The greater changes happened in the diametric class of 10 to 20 cm of DAP. For the analyzed populations, it was confirmed different demographic behavior. In relation to the individuals number and basal area, the Capivari forest is the most stable among the studied, until the moment, at Upper Rio Grande region.

ASSUNTO(S)

recursos florestais e engenharia florestal forest dynamics, forest fragmentation, tropical semideciduous dinÃmica florestal. fragmentaÃÃo florestal. floresta estacional

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