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The NatureServe conservation status system was developed by NatureServe, The Nature Conservancy (TNC) and the Natural Heritage Network as a ranking of the relative imperilment of species on global, national and/or regional levels. It is also called TNC ranks or the NatureServe status.

In the system, G codes refer to rankings made at the global level (G-rank), N codes refer to rankings made at a national level (N-rank) and S codes refer to rankings made at the sub-regional level (S-rank), such as states within the US:

• X - presumed extinct (not located despite extensive searches)
• H - possibly extinct [or h historical occurrence (still some hope of discovery)]
• 1 - critically imperilled (typically five or fewer occurrences or 1,000 or fewer individuals)
• 2 - imperilled (typically six to twenty occurrences or 1,000 to 3,000 individuals)
• 3 - vulnerable (rare; typically 21 to 100 occurrences or 3,000 to 10 000 individuals)
• R or ? - Recorded within nation or state, but local status not available; when combined with global rank of G1 to G3, local status is 'Indeterminate'
• 4 - Apparently secure (uncommon but not rare; some cause for long-term concern, usually more than 100 occurrences and 10,000 individuals)
• 5 - Secure (common, widespread and abundant)

Thus, for example, a G3 species is "globally vulnerable", and an N2 species is "nationally imperilled" for whatever country the rank is assigned. Species with G, N, or S rankings of 4 or 5 are generally not the basis for major conservation actions.

Infraspecific taxa (subspecies, varieties and other designations below the level of the species) can also be assigned T-ranks, which is appended to the G-rank.

See also

• Conservation status

External link and references

• http://www.unep-wcmc.org/species/plants/status_tnc.htm