Global and State Rank Codes for Natural Communities
The New Hampshire Natural Heritage Bureau assigns conservation status ranks to natural communities based on assessments of rarity, trends, and threats. These ranks provide estimates of the risk of elimination. Use of standard criteria and rank definitions as defined by NatureServe and its member programs make these ranks comparable across community types and political boundaries.
Ranks are assigned for global status (G), which includes the entire range of a natural community, and statewide status (S). When a precise rank is unclear or the status of a natural community appears to fall between two ranks, a range may be used. For example, the range G4G5 could indicate that a community’s global status rank is unclear but either 4 or 5, or that its rank is near the border between the two.
1 Critically Imperiled: At very high risk of elimination due to extreme rarity (generally one to five occurrences), very steep declines, or other factors.
2 Imperiled: At high risk of elimination due to a very restricted range, very few examples (generally six to twenty occurrences), steep declines, or other factors.
3 Vulnerable: At moderate risk of elimination due to restricted range, relatively few examples (generally twenty-one to one hundred occurrences), or vulnerable to elimination because of other factors.
4 Apparently Secure: Uncommon but not rare; some cause for long-term concern due to declines or other factors.
5 Secure: Demonstrably common, widespread, and abundant.
U Uncertain: There is evidence that a community may be eliminated throughout its range, but not enough evidence to state this with certainty. More information needed.
H Historical: Known only from historical records, but with reasonable possibility of rediscovery.
X Eliminated: Eliminated throughout its range, with no restoration potential due to extinction of dominant or characteristic taxa and/or elimination of the sites and disturbance factors on which the community type depends.