Increasing resource specialization among competitors shifts control of diversity from local to spatial processes

We argue that an increase in the number of specialized consumers can shift the control of ecological dynamics from local to spatial processes. When there are only a few specialized types, local dynamics maintains most types within each patch. As the number of types increases, the probability of local extinction rises. Subsequent colonizations perturb local dynamics, setting off another round of extinctions and the potential for later recolonization. Global processes of colonization and extinction reduce local diversity and increase differentiation among patches. We draw an analogy between the specificity of host-parasite genetics and the specificity of consumer–resource pairs.