Fonseca, M.G., Martini, A.M.Z. & Santos, F.A.M. 2002. Population dynamics and spatial variation in size structure of Aspidosperma polyneuron in SE Brazil. 45th Symposium of the International Association for Vegetation Science, p. 45.

Abstract: Population dynamics and the spatial variation in size structure of Aspidosperma polyneuron, were studied in two fragments of semideciduous forest, the Reserva Municipal de Santa Genebra (SG; 22°49’S 47°06’W) and the Mata do Ribeirão Cachoeira (RC; 22°50’S 46°55’W; distant 14 km from SG), in SE Brazil. The annual mortality and recruitment of adults (DBH >= 5cm) were analyzed in a 1-ha area in SG between t0 (1982/1985), t1 (1994/1995) and t2 (1999), and for saplings (DBH < 5cm), in half of the area, between t1 and t2. Data were also analyzed with a matrix model. The size structure was described in two other 0.5-ha areas, one in SG (distant 200m from the former) and another in RC. Size structure varied in space, and the differences were higher within than between fragments. The number of saplings (between t1 and t2) and adults (between t0 and t2) decreased at a rate of 2.7% year-¹ due to the low rate of recruitment in these classes (2.1% and 0.4%, respectively). The studied period may represent a phase of decline in a natural cycle of stochastic fluctuations, or density-dependent processes may be regulating the high density of the species (140 individuals ha-¹). We suggest that the high liana infestation is preventing the saplings from reaching the reproductive stage. In this case, the control of lianas as well as the planting of seedlings of the species would be necessary to reserve the process of decline.