Species at Risk
Source: The Nature Conservancy and Nature Serve-Association for Biodiversity Information
Map Description:
This map depicts the percentage of species at risk per state in the U.S. The map and text are from the excellent publication entitled "Precious Heritage: The Status of Biodiversity in the United States", by The Nature Conservancy and Association for Biodiversity Information.(fig. 5.1c, pg. 124). Rarity patterns largely correspond to overall diversity, and California again leads the nation, with more than 1,800 rare species, or almost one-third (32%) of its total. The most significant differences between the patterns of rarity and diversity, however, relate to two of the states with the fewest species. Hawaii's more than 800 rare species translate into fully 66% of its total, by far the largest proportion of any state. Alaska, too, shifts considerably in significance: With 8% of its species at risk, Alaska ranks high among states based on proportion of rare species, compared with its near-last ranking for total species diversity. In general, however, states with the highest diversity are also those with the highest levels of rarity. Among the most diverse states- those with 3,000 species or more- levels of rarity typically exceed 10%.

Cautions for this Product:
Combining native species of vascular plants, vertebrates, and two invertebrate groups, mussels and crayfish, creates an aggregate data set representing 19,101 species. This map depicts overall patterns which refer only to regularly occurring native species in these plant and animal groups. A great many other species of invertebrates, nonvascular plants, algae, fungi, and microorganisms also are found in these states. However, currently, comprehensive information on these groups, which would enable their inclusion in an analysis of overall state-level diversity patterns, is unavailable.
Map used with permission from The Nature Conservancy and Oxford Press.

For Further Information:
"Precious Heritage: The Status of Biodiversity in the United States", B. Stein, L. Kutner and D. Adams, editors. Oxford Press. 2000.