XVI International Botanical Congess

Tropical forests are experiencing major disruptions by land use patterns leading to reduced size and fragmentation. These, together with contemporary hunting, are causing a significant pulse of defaunation, affecting particularly large mammals. I analize how defaunation affects the patterns of understory herbivory, floristic diversity and how this in turn affects the patterns of attack by natural enemies. The studies suggest that the loss of mammalian herbivores triggers a cascade of effects whereby levels of mammalian herbivory are reduced, and understory plant diversity is impoverished. Impoverished understories attract high numbers of caterpillars but compensating insect herbivory is prevented by the concurrent increase of natural enemies. Current massive defaunation seems to affect the most distinctive attribute of tropical forests: their biological diversity and functioning.