Tree population dynamics in alluvial forest fragments in south of Minas Gerais, Brazil

Abstract

The present study aimed to evaluate the tree population dynamics in forest fragments, in the municipality of São Sebastião da Bela Vista, MG. For this sake, all living trees with diameter at breast height (DBH) higher than 5 cm, present in the sampled units, were measured (DBH and height) and identified in 2005 and monitored in 2007 and 2009 (remeasured and mortality evaluation), when all individuals reaching the minimum diameter of inclusion, on the occasion of a possible recruitment, were recruited. The annual dynamics rates (mortality, recruitment, turnover and net change) were calculated for all populations. Dynamics instability was observed, indicated by the steady reduction of abundance and the higher number of species with negative balance in abundance (period 2005 a 2007 = 13 e 2007 a 2009 = 17) than positive balance (2005 a 2007 = 9 e 2007 a 2009 = 14). The richness changes were insignificant, with the gain of two species and loss of just one. The present study demonstrated that, despite the observation of no qualitative (floristic) changes, the evaluated area showed a dynamics with structural instability, with higher mortality than recruitment.