Diversity Storage: Implications for tropical conservation and restoration

The future of tropical biodiversity in human-dominated landscapes will be conservation and restoration of processes of seed dispersal by birds and mammals. Here the Diversity Storage Hypothesis posits that immense biological diversity resides within skewed species abundance distributions of tropical trees, and further predicts that many species will adjust to increases of 1.5–3.0 °C anticipated from climate change by 2100. Common and widespread tropical trees (>100,000,000 individuals) may shift ranges but are unlikely to face extinction. Many rare species (e.g. <1000 individuals) have a more precarious future. The latter may be declining species bound for extinction, incipient species adjusting to environmental changes, or relics of past warmer and more seasonal climates that will be resurrected if processes of seed dispersal allow them to persist and spread. In fragmented agricultural landscapes, preserved or planted corridors, buffers and stepping-stone habitat patches around and between forest remnants are more vital than efforts to preserve or create contemporary forest compositions, dominance relations, and species-abundance distributions. An implication of Diversity Storage is that it is more important to facilitate migration into and out of changing landscapes to allow inherent diversity to adjust and coexist with agricultural economies than to resist change.