Recovery of Disturbed Ecosystems as Monitored by Ant and Vegetation Diversity in Forests and Surrounding Savannas of Venezuela

Abstract

The recovery of tropical ecosystems after disturbance is of interest for future programs of sustainable development. The dynamics of such processes was evaluated at 26 sites in Venezuela. Ant and plant diversity were compared between disturbed forests and surrounding savannas, different stages of recovery and nearby plots with primary vegetation. We estimated the species composition for ants, the number of species and equitability for ants and plants, and the plant coverage at each site. Of these indices, percentage of plant cover showed the most rapid return to pre-disturbance values. In a few cases, full return occurred after around 25 years in both savanna and forest. A multiple factorial analysis of ant composition showed that species structure in old recovered sites converged sometimes, but not always, to that in surrounding natural habitats. Therefore, ant diversity may be used to monitor ecosystem recovery. However, even small scale human intervention may have irreversible effects on tropical habitats. The estimated time constant for forest recovery could serve to calculate human carrying capacity of forest sites for eventual sustainable use of these ecosystems in the Neotropics.