Disruption of Plant-Herbivore Interactions in Light of the Current Defaunation Crisis

Abstract

In this chapter we examine how the current patterns of anthropogenic impact on biodiversity are engendering a pulse of animal life loss - defaunation - with emphasis on the decline and massive extinction of populations of mammals. Given that many species of this group operate as herbivores and, due to their local abundance in some regions and ecosystems of the world, have the potential to affect plant performance and survival, their decline or outright local extinction significantly disrupt the patterns of mammalian herbivory, in some cases causing the local extinction of this critical interaction affecting the structure and composition of communities and ecosystems. Our chapter, addressing a different group of herbivores than that examined in the other chapters of the volume, as well as addressing species interactions in defaunated systems, includes an analysis of mammalian herbivores in the context of insect herbivores, a historical account of the development and evolution of defaunation science, and a discussion of the methods available to document defaunation. (We hope that the inclusion of such contextual analysis and historical and methodological accounts will be of some use for the readers who are not familiar with this field.) This is followed by a brief exposé of the disruption of mammalian herbivory and its consequences at the community and ecosystem levels.