Trade‐offs, temporal variation, and species coexistence in communities with intraguild predation
2007
Amarasekare, Priyanga
Intraguild predation/parasitism (IGP: competing species preying on or parasitizing each other) is widespread in nature, but the mechanisms by which intraguild prey and predators coexist remain elusive. Theory predicts that a trade‐off between resource competition and IGP should allow local niche partitioning, but such trade‐offs are expressed only at intermediate resource productivity and cannot explain observations of stable coexistence at high productivity. Coexistence must therefore involve additional mechanisms beside the trade‐off, but very little is known about the operation of such mechanisms in nature. Here I present the first experimental test of multiple coexistence mechanisms in a natural community exhibiting IGP. The results suggest that, when resource productivity constrains the competition–IGP trade‐off, a temporal refuge for the intraguild prey can not only promote coexistence, but also change species abundances to a pattern qualitatively different from that expected based on the trade‐off or a refuge alone. This is the first empirical study to demonstrate a mechanism for why communities with IGP do not lose species diversity in highly productive environments. These results have implications for diversity maintenance in multi‐trophic communities, and the use of multiple natural enemies in biological control.
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