Multiple scales and the maintenance of biodiversity

The problem of multiple scales permeates the study of ecological process and pattern, uniting aspects of space, time, and organizational complexity. In particular, it supports the maintenance of biological diversity, allowing for the magnification of underlying patterns of variation in the physical environment to create many resources from few, through the evolutionary diversification of species' niches and life histories. Specialization to particular stages of a successional gradient facilitates coexistence of multiple types in the presence of uncorrelated local disturbances, such as gap formation, which reinitiate successional sequences. Superimposed upon such successional dynamics are the effects of multiple stable states and multiple successional pathways (Levin 1976), which increase diversity even more. Multiple stable states more generally raise the possibility of sudden flips of systems from one stable configuration to another, and with such changes may come huge changes in the biotic composition. On larger spatial scales and longer time scales, these flips may become correlated resulting in the transformation of the landscape, or may result in sustained spatiotemporal mosaics of states. Instability at the local level may lead to the maintenance of biodiversity on broader scales. Finally, the ultimate scale mismatch involves that between the dynamics of natural systems and the cultural dynamics of human societies. Our ability to live sustainably in a global commons is dependent upon adjusting normative behavior, and tightening feedback loops more generally, so that individual actions serve the common good.