Linking Habitat Restoration to Meaningful Units of Animal Demography

To restore habitat is to restore the functional aspects of a place where one or more species are intended to live. However, habitat restored with the right structural elements can still fail to support the species due to insufficient space and spatial contiguity (e.g., movement corridors) with nearby habitat. The spatial extent of habitat determines its capacity to support various demographic units, such as a breeding pair of individuals, a true population, or a metapopulation. In scatter‐plots of published density estimates and their corresponding study area sizes, I found consistent patterns that appeared to represent spatial scale domains, in which subpopulations, populations, and multiple populations exist for each species. These spatial scale domains can help guide habitat restoration by indicating the minimum area needed to support a population. The effectiveness of restored habitat, considered alone or in combination with existing habitat, should be judged by the habitat's capacity to sustain a functioning population, which includes the population's membership in a metapopulation. Additionally, the evidence increasingly demonstrates that habitat must include sufficient space for the population(s) to periodically relocate as resources are depleted locally. The spatial extent of proposed habitat restoration can now be linked to the likely demographic unit of the species that can be supported there. I provide two examples of proposed habitat conservation and their likely effectiveness based on their spatial areas.