We developed a geographic information system including ArcView 3.1 shapefiles for each species (5, 9). The files contain the known geographic range depicted by a boundary map (extent of occurrence) (9). Species richness was defined as the total number of mammal species in a single cell. Restricted-range species referred to the total number of species in each cell having a geographic range less than or equal to 250,000 km2. Threatened species in each cell were all species considered threatened, endangered, or critically endangered by the International Union for the Conservation of Nature and Natural Resources (IUCN) (31). Finally, we carried out an optimization analysis using a complementarity algorithm (MARXAN) to assess the efficiency of hotspots in representing the three different aspects of mammal diversity. The analysis selects the minimum number of grid cells required to represent all species in each category in the three kinds of hotspots (2, 15).
Acknowledgments
We thank I. Salazar for helping with the data analysis. Mark Lomolino, Rob Channel, Rodrigo Medellin, Pablo Ortega, Rob Pringle, and Jai Ranganathan read and commented on the manuscript. This study was supported by the National University of Mexico, the John Simon Guggenheim Memorial Foundation, the Comisión Nacional para el Conocimiento y Uso de la Biodiversidad (CONABIO) (Mexico), the Center for Conservation Biology–Stanford University, EcoCiencia (Mexico), and the LuEsther T. Mertz-Gilmore Charitable Trust.
Footnotes
The authors declare no conflict of interest.
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