Tree community reassembly after selective and clear-cut logging in an Afro-tropical rainforest

Abstract

Understanding the process of community reassembly is crucial for the conservation of biodiversity and rehabilitation of ecosystems. This study tested whether tree communities in logged forests follow an equilibrium (deterministic) or non-equilibrium (stochastic) model of succession. We assessed reassembly of tree communities in different size classes along a successional gradient consisting of nine differently aged successional forests, namely, four regenerating former clear-cuts (9–19 years), three selectively logged (42–43 years) and two primary forests (PFs) in Kibale National Park, Uganda. The results show that the forests are converging and undergoing reassembly towards PFs. The species composition of seedlings, saplings and poles declined in similarity to the PF with age but that of mature trees in the different successional stages increased towards the PFs. These differences in tree species composition among the different size classes might be due to dominance of some particular species. Recovery of tree species density, diversity and dominance in all the size classes showed directional patterns as predicted by the deterministic model of succession. Compared to other variables, tree species density and diversity in selectively logged forests recovered relatively faster and was equivalent to or higher than that of PFs at 43 years. The results of the present study indicate that community reassembly in smaller sized trees followed a stochastic model of succession. However, as trees matured, they conform to the deterministic model of succession.