Indirect commensalism promotes persistence of secondary consumer species.
Local species extinctions may lead to, often unexpected, secondary extinctions. To predict these, we need to understand how indirect effects, within a network of interacting species, affect the ability of species to persist. It has been hypothesized that the persistence of some predators depends on other predator species that suppress competitively dominant prey to low levels, allowing a greater diversity of prey species, and their predators, to coexist. We show that, in experimental insect communities, the absence of one parasitoid wasp species does indeed lead to the extinction of another that is separated by four trophic links. These results highlight the importance of a holistic systems perspective to biodiversity conservation and the necessity to include indirect population dynamic effects in models for predicting cascading extinctions in networks of interacting species.
Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Cornwall Campus, Penryn, Cornwall TR10 9EZ, UK.
Dirk
D
Sanders
F J Frank
FJ
van Veen
D000818:Animals; D001042:Aphids / Q000502:physiology*; D003247:Conservation of Natural Resources / Q000379:methods; D053476:Extinction, Biological; D020387:Food Chain; D016013:Likelihood Functions; D008954:Models, Biological; D011157:Population Dynamics; D013045:Species Specificity; D014863:Wasps / Q000502:physiology*