Conservation Status

NatureServe data track two primary types of conservation status information: NatureServe Conservation Status Ranks and Federal-Level Legal Status.

Federal-Level Legal Status

NatureServe Surveyor can return data about species with some level of designation under the processes and definitions of the U.S. Endangered Species Act, which is administered by the U.S. Fish and Wildlife Service and the National Marine Fisheries Service, and the Species at Risk Act, administered by the Canadian Wildlife Service.

NatureServe Conservation Status Ranks

Only a small proportion of species that NatureServe and other biodiversity experts considers to be globally imperiled have federal-level legal status in either the United States or Canada. NatureServe and its member programs have developed a scientific method for evaluating the relative imperilment of species. These “status assessments” are based on the best available information and consider a variety of factors such as abundance, distribution, population trends, and threats.

We strongly recommend consideration of NatureServe conservation status, in addition to legal status, when reviewing and using the information provided via NatureServe Surveyor.

The conservation status of a species is designated by a number from 1 to 5, preceded by a letter reflecting the appropriate geographic scale of the assessment (G=Global, N=National, and S=Subnational). The numbers indicate the degree to which the species is considered at risk, as follows:

1 = critically imperiled
2 = imperiled
3 = vulnerable to extirpation or extinction
4 = apparently secure
5 = demonstrably widespread, abundant, and secure

For example, G1 would indicate that a species is critically imperiled across its entire range (i.e., globally). In this sense the species as a whole is regarded as being at very high risk of extinction. A rank of S3 would indicate the species is vulnerable and at moderate risk within a particular jurisdiction, even though it may be more secure elsewhere. Infraspecific taxa—subspecies, varieties, and other designations below the level of the species—have range-wide assessments preceded by a T rather than a G.

Learn more about NatureServe conservation status.