Print PageLocal-regional species richness relationships have been used to infer relative contributions of local and regional forces to determining the richness of local communities. Although most previous research assumed competition as major local species interactions, growing empirical evidence suggests that facilitation is also an important driver of local community dynamics. Here I explore how facilitation affects the shape of local-regional richness relationships, by incorporating local facilitation into a patch occupancy model of metacommunity dynamics.
Results/Conclusions
I find that facilitation can generate either local-regional richness relationships with accelerating slopes, or those with the alternative stable states. Harshness of the environment affects which pattern arises. There appear to be a number of published local-regional richness relationships that resemble the predicted pattern with accelerating slopes. This result suggests that taking local facilitation into account is important when interpreting the shapes of local-regional richness relationships. Moreover, the possibility of alternative stable states suggests that gradual decline of regional species diversity might cause a sudden collapse of metacommunities with local facilitation.
