Percent Aridland Area by Terrestrial Ecoregion

Percent of ecoregion area covered with desert and aridland habitat.

We derived the aridlands map by first developing a raster-based mask of arid climates from the Köppen-Geiger climate classification (Kottek et al. 2006) using ArcInfo GIS software. We applied the mask to the GLC 2000 global land cover, and then extracted sparse vegetation classes. For example, pockets of forested land occurring within Köppen-Geiger arid climate regions were excluded. Areas of human habitation and infrastructure were also removed from the map, leaving only natural desert lands. Finally, we applied a zonal sum procedure to the raster map to calculate the percentage of arid land per ecoregion.

These data were derived by The Nature Conservancy, and were displayed in a map published in The Atlas of Global Conservation (Hoekstra et al., University of California Press, 2010). More information at http://nature.org/atlas.

Data derived from:
Center for International Earth Science Information Network (CIESIN), International Food Policy Research Institute (IFPRI), the World Bank, and Centro Internacional de Agricultura Tropical (CIAT). 2004. Global Rural-Urban Mapping Project (GRUMP): Urban Extents, Columbia University Palisades, New York. Available at http://sedac.ciesin.columbia.edu/gpw/.

Hijmans, R. J., S. E. Cameron, J. L. Parra, P. G. Jones, and A. Jarvis. 2005. Very high resolution interpolated climate surfaces for global land areas. International Journal of Climatology 25: 1965–1978. Available at www.worldclim.org.

Joint Research Centre of the European Commission (JRC). 2003. Global Land Cover 2000 database. Ispra, Italy: European Commission Joint Research Centre, Institute for Environment and Sustainability. Available at www.gvm.sai.jrc.it/glc2000/defaultGLC2000.htm.

Kottek, M., J. Grieser, C. Beck, B. Rudolf, and F. Rubel. 2006. World map of the Köppen-Geiger climate classification updated. Meteorologische Zeitschrift 15: 259–263.