Tracking population extirpations via melding ecological niche modeling with land-cover information

We explored a new approach to tracking population losses in poorly known species across broad spatial scales, based on integration of tools from ecological niche modeling with data resources derived from remotely sensed land-cover information. Ecological niches were modeled based on known occurrences of species (natural history museum specimen data) and environmental dimensions including topography, climate and original vegetation; these niche models were then projected onto land use/land-cover maps (with classes equivalent to those in the original vegetation dataset) based on air photography and LandSat imagery from 1976, 1993 and 2000, to track loss of potential distributional area over two decades. As an illustration, we analyzed 11 endemic Corvidae (jays) in Mexico; the method is applicable to any species for which distributional information exists and any region for which multitemporal land-cover information has been developed. We envisage this approach evolving into a population loss meter, permitting monitoring of losses of species-specific combinations of environmental and landscape features.