Local vs. landscape-level effects on recovery of biodiversity in abandoned agricultural land

The number of long-term studies of tropical forest recovery on post-agricultural lands is increasing.  Synthesizing the results of these studies can help design tropical forest restoration strategies that maximize limited restoration resources.  Past studies show a surprising degree of resilience of tropical forests from human disturbance, although the variation in rate of recovery and direction of successional trajectory is high.  Much variation can be explained by differences in abiotic conditions, surrounding landscape, and past land use type and intensity. Unfortunately, few past studies of regeneration and restoration have compared the relative importance of factors at different scales on forest regeneration, as most have been conducted on small plots and at single sites.  We summarize results from two restoration case studies to illustrate how understanding spatial and temporal patterns of tropical forest recovery can inform restoration efforts.  First, we discuss an ongoing study measuring recovery of plant communities and patterns of bird use at 16 sites surrounded by a forest cover of <5-50% spread across >100 km² in southern Costa Rica.  Thus far, results suggest that local scale restoration efforts more strongly affect forest recovery than location in the landscape in this system, although this may change as sites continue to recover.  Second, we present results of a tropical dry forest study in Brazil demonstrating the importance of understanding the effect of both past land use and restoration strategies on ecosystem recovery.  Results show that the commonly-used practice of planting tree seedlings actually slows natural forest recovery.