Direct and indirect effects of invasions of predators on a multiple-species community

A Lotka-Volterra system for a multiple species community with two trophic levels is analyzed to illustrate how community structure is reorganized upon invasions of predators. The lower trophic level is assumed to consist of interfering competing species, some of which are preferentially consumed by invading predators. Effects of invading predators on the lower trophic level are investigated in terms of predator-mediated coexistence and predator-induced instability. Competitive interactions between species in the lower trophic level result in indirect mutualism or indirect competition between predators depending on which competitors are preyed upon.