UC Santa Cruz

We summarize research on diversity and trophic interactions under a trophic cascades model that is reframed and expanded from the traditional biomass- or abundance- based indirect effects and discuss the response of such "diversity cascades" to climate change and other global change parameters. The studies we summarize encompass dynamic processes in which species richness or evenness in one trophic level indirectly affects or is affected by changes in a non-adjacent level. The diversity cascade concept explicitly links trophic cascades models to the debates about biodiversity loss, exotic species gain, ecosystem services and biological control. First, we summarize the idea that the trophic cascades model includes different currencies and alternative processes. Second, we question the paradigm that trophic cascades weaken as the complexity of the community increases. Third, we illustrate the mechanisms by which diversity cascades may follow indirect bottom-up and top-down pathways. Fourth, we show how this diversity cascades model has been applied successfully to frame questions in conservation, agriculture and infectious disease. Finally, we examine the implications of diversity cascades for our understanding of how climate change affects biodiversity and call for an increase in the scope of experiments and focused hypotheses on indirect trophic effects and how these processes may lead to very large changes in biodiversity. © 2013 by the authors; licensee MDPI, Basel, Switzerland.