Hoekstra et al. [1]

Hoekstra et al. [1] attempt to identify ``those terrestrial biomes and ecoregions in which biodiversity and ecosystem services are at greatest risk because of disparities in the extent of habitat loss and protection.'' Biomes are broad-scale biogeographic regions, e.g., tundra or temperate broadleaf forest. Olson et al. [4] recognize fourteen terrestrial biomes. Within each biome they recognize 867 ecoregions: ``relatively large units of land containing a distinct assemblage of natural communities and species, with boundaries that approximate the original extent of natural communities prior to major land-use change'' (Figure 2).

Figure 2: The 867 ecoregions of the world (from [4]).

• Using Global Land Cover 2000 dataset, calculate percent of each biome and ecoregion area classified as cultivated and managed or artificial surfaces and associated areas.

• Using 2004 World Database on Protected Areas, calculate percent of each biome and ecoregion area classified as covered by a designated protected area, including those areas designated as multiple use.

• ``Crisis ecoregions'' - those with high percentage of ecoregion area converted and low percentage of ecoregion protected (Figures 3 and 4).

  Figure 3: Quantitative criteria for recognizing ``crisis ecoregions'' (from [1]).

  

  Figure 4: Geographic distribution of ``crisis ecoregions'' (from [1]).