Note that the data published in the 2002 State of the Nation’s Ecosystems Report as well as the 2003 and 2005 Web-Only Updates have been superseded by the 2008 Report and thus should be used with caution. For the most recent data, purchase the 2008 Report from Island Press.

View Data for At-Risk Species, by Region

Interpreting these figures is complicated because some species are naturally rare. Thus, the rankings are influenced by differences among regions and species groups in the number of naturally rare species, as well as by different types and levels of human activities that can cause species declines. Interpretation of these data will be greatly enhanced when information on population trends for these at-risk species becomes available.

Why Can't This Entire Indicator Be Reported? Data are not available on at-risk species in U.S. coastal waters.

Discussion At least 200,000 native plant, animal, and microbial species are thought to live in the United States, but little is known about the status and distribution of most of these. This indicator summarizes the status of 16,000 plant species and 6,000 animal species, which include all 22 species groups for which comprehensive status assessments are available. These species represent all higher plants, all terrestrial and freshwater vertebrates (mammals, birds, reptiles, amphibians, and freshwater fishes), selected invertebrate groups, including freshwater mussels and snails, crayfishes, butterflies and skippers, and about 2,000 species of grasshoppers, moths, beetles, and other invertebrates. This sample of species is believed to provide a powerful, yet practically manageable snapshot of the condition of U.S. species.

See http://www.natureserve.org/explorer/ranking for a description of these conservation status ranks and details of the assessment criteria.

See also the indicators for at-risk coastal, forest, freshwater plants and animals, and grassland and shrubland species, as well as those for species in farmland and urban and suburban areas.