Volume 47, Issue 1, Spring 2019
The Philosophy of Ecology
Gregory J. Cooper, Lawrence E. Hurd
The House and the Household
Habitat, Demographic Independence, and Ecological Populations
The concept of population is central to ecology, yet it has received little attention from philosophers of ecology. Furthermore, the work that has been done often recycles ideas that have been developed for evolutionary biology. We argue that ecological populations and evolutionary populations, though intimately related, are distinct, and that the distinction matters to practicing ecologists. We offer a definition of ecological population in terms of demographic independence, where changes in abundance are a function of birth and death processes alone. However, demographic independence (DI) is insufficient on its own so we supplement it with the idea of shared habitat. An ecological population is a group of organisms of the same species in a habitat that manifests DI. Given the importance of metapopulation dynamics to modern ecology, an account of ecological population must apply to this domain as well. Thus, we extend our definition of ecological population to the metapopulation. To facilitate the extension, we introduce the metahabitat—a collection of spatially segregated habitat patches shared by a single DI population. This enables us to (1) diagnose some unhelpful trends in the metapopulation literature and (2) emphasize the importance of habitat dynamics in pursuit of the goals of theoretical ecology and conservation biology.