Print PageThe effect of habitat destruction on species richness has been predicted using a variety of theoretical approaches. However, a shortcoming of many of these approaches is that they consider how species richness scales across infinite area. With habitat destruction, there is a reduction in a total finite area of habitat, which can influence the scaling of species richness in ways not predicted by an infinite-area model. Here, we used metacommunity theory to examine the influence of habitat destruction (i.e., changing metacommunity size) on species richness across spatial scales. Specifically, we incorporated metacommunity size into the standard Equilibrium Theory of Island Biogeography in two different ways: by increasing patch immigration rates, and by decreasing patch extinction rates, with increasing metacommunity size. By summing the accumulation of species across patches, we theoretically examined how changes in metacommunity size (through habitat destruction), can change the scaling of species richness with area.
Results/Conclusions
When we assumed that metacommunity size increased patch immigration rates, we found a reduced magnitude of the slope of the species-area relationship in larger metacommunities. Conversely, when we assumed that metacommunity size decreased patch extinction rates (i.e., through the rescue effect), we found an increased slope of the species-area relationship in larger metacommunities. This model presents two opposing scenarios for the effects of habitat destruction on species accumulation patterns, which can be validated through future empirical and observational work. The likelihood of each scenario will depend upon the influence of metacommunity size on immigration and extinction rates in a particular system.
