Persistence of intraguild prey and predators in source-sink meta-communities

Dispersal of organisms in a heterogeneous landscape strongly influences the persistence of indirectly interacting populations. The source-sink dynamics is one of the major mechanisms to promote coexistence of locally exclusive competitors. Recently, it was found that two populations that compete exploitatively (Namba and Hashimoto, 2004; Abrams and Wilson, 2004) or apparently (Namba, in press) in source-sink metacommunities can coexist regionally even if one of them is locally inferior in both habitats. In this talk, I consider a Lotka-Volterra model of intraguild prey and predators in two different habitats connected by dispersal of organisms and study the conditions for coexistence and competitive exclusion, (1) when the intraguild prey is inferior in both patches, (2) when the intraguild predator is inferior in both patches, and (3) when the local interactions are bistable and either of the intraguild prey and predator can dominate each habitat if it is initially abundant. In particular, I will show that either the intraguild prey or predator can persist regionally in a source-sink metacommunity even if it is competitively excluded in isolated habitats in the absence of dispersal.