Santos, F.A.M., Tamashiro, J.Y., Rodrigues, R.R. & Shepherd, G.J. 1996. The dynamics of tree populations in a semideciduous forest at Santa Genebra Reserve, Campinas, SE Brazil. Supplement to Bulletin of the Ecological Society of America (1996 Annual Combined Meeting “Ecologists/Biologists as Problem Solvers”, Abstracts, Providence, Rhode Island), 77 (3): 389. Abstract: In this study we examined changes after a 12-year period in the structure and composition of a semideciduous forest based on an 1-ha sample in a Reserve (of 250 ha), in SE Brazil, by comparing recruitment, mortality and growth of trees greater than 5cm dbh. Species richness increased during the period (103 to 117), including 3 lost and 17 recruited species in the sampled area. Tree density declined about 12% (1463 to 1283/ha) and basal area increased about 12% (24.9 to 28.0 m²/ha). Mortality rates were independent of size class. Among the 99 species present over the whole period, only 4 showed a significant decrease in population density and 4 others showed a significant increase in population density. Mortality was greater than average (3.5%/yr) for pionee species (7.5%/yr). Recruitment and mortality differed significantly from overall rates for some species. This was marked for 11 of the 24 more common species, but only 5 of these showed an imbalance between rates. Mean annual growth in diameter varied from 1.4 mm/yr for smaller trees (5 to 10 cm dbh) to 9.1 mm/yr for bigger trees (greater tham 40 cm dbh) and was greater for pioneer species (6.5 mm/yr). Mortality was clustered and recruitment was random, resulting in a change of the spatial pattern of trees in the area. |