Dinâmica das comunidades arbóreas de mata de galeria da Estação Ecológica do Panga, Uberlândia - MG (1989 - 2002)

Abstract

A study of the dynamics of two gallery forest tree communities was carried out. The study area is located in the margin of the Ribeirão Panga in the Panga Ecological Station, Uberlândia, Minas Gerais - Brazil. The objective of this work was to analyze the mortality processes, growth and recruitment of the arboreal stratum, in a 13 year-old period (1989 -2002). In two areas of approximately one hectare each, 30 portions of 10 x 10 m were allocated, distributed, according to the environmental variations present in the area (“Dique", “Meio” and “Borda sites”). A survey in each study area (area 01 and 02), involved measures of circumference at breast height (CBH), of all alive individuais with CBH > 15 cm. The species were reorganized in groups with the objective of facilitate the visualization of the species distribution in bach environment microsites and comparison with similar groups organized during the first study (1989). For area 01, the 1989 survey (T1) registered a total of 47 species and 501 individuais. The second survey in 2002 (T2), presented 50 species, including 10 new ones and 444 individuais. The area presented mortality and recruitment rates of 1,81% and 2,63% respectively. The loss in basal area (2,596 m2) was superior to the survivors' growth (2,381 m2) and to the increment promoted by the recruitment (0,566 m2). The area 02, had a total of 73 species and 488 individuais in T1 and 73 species and 451 individuais in the T2. Mortality and recruitment rates of 0,71% and 2,23% respectively. The loss in basal area (1,44 m2) was superior to the survivors' growth (1,04 m2) and to the increment promoted by recruitment (0,064 m2). The area 01 presented greater instability due to environmental changes, mainly in soil moisture conditions, which promoted some species substitutions. The area 02, characterized in the T1 as a more mature environment, shoned no important changes, which indicates greater stability.