THE GLOBAL 200 A Representation Approach to Conserving the Earth’s Distinctive Ecoregions World Wildlife Fund, (Olson and Dinerstein, 1997)
To better incorporate representation of the Earth's distinctive ecosystems in conservation strategies, WWF's scientists conducted an analysis of ecoregions representing the Earth's 19 terrestrial, freshwater, and marine major habitat types. Based on a comparative global analysis and synthesis of five extensive regional studies, these scientists identified 233 ecoregions (the Global 200) that are outstanding examples of the world's diverse ecosystems and priority targets for conservation action. These include 136 terrestrial, 36 freshwater, and 61 marine ecoregions. Selection of ecoregions was based on analyses of species richness, species endemism, unique higher taxa, unusual ecological or evolutionary phenomena, and global rarity of major habitat types. Outstanding ecoregions were selected within each major habitat type from each of the world's biogeographic realms and ocean basins to better capture the variation in species assemblages around the world.
The current extinction crisis requires dramatic action to save the variety of life on Earth. Because funding for conservation action is limited, governments, donors, and conservation groups must be strategic and earmark the greatest amount of resources for protecting the areas richest in biodiversity. Most conservation biologists recognize that although we cannot save everything, we should at least ensure that all ecosystem and habitat types are represented within regional conservation strategies.
(n) = Number in WWF Global 200 Manuscript CE = Critical or endangered
[n] = Number in modified ecoregions RS = Relatively stable or intact
5 out of 136 Global 200 terrestrial ecoregions = 3.6%
TROPICAL & SUBTROPICAL DRY & MONSOON BROADLEAF FORESTS
(56) Southern Mexican Dry Forests, Mexico [75,76,77,78,79,80,83]CE The tropical dry forests of southern and southwestern Mexico are noted for high levels of regional and local endemism in a wide range of taxa. The richest tropical dry forests in the world with high levels of regional and local endemism.
TROPICAL AND SUBTROPICAL CONIFER FORESTS
(64) Mexican Pine-Oak Forests - Mexico, United States [114,115,116,117,118]CE This ecoregion contains some of the world’s most extensive subtropical coniferous forests. Many plants and animal species are restricted to single ranges or individual peaks or watersheds throughout the region, notably birds, conifers, reptiles and amphibians. These are the richest subtropical conifer forests in the world.
DESERTS & XERIC SHRUBLANDS
(121) Sonoran & Baja Deserts - Mexico, United States [161.162,163,76] V The cactus scrub communities of the northern Sonora desert have some of the most diverse and unusual desert plants and animals in the world. Forests of giant cacti are notable here and are associated with a rich variety of plants and animal species. Neotropical deserts with high endemism at species and higher taxonomic levels and globally distinctive communities dominated by massive columnar cacti.