The Natural Heritage Conservation Ranks
The Global (G) Rank reflects the conservation status of a species from a global (i.e., range-wide) perspective, characterizing the relative rarity or imperilment of the species. Global conservation status ranks are based primarily on three factors: number of occurrences; total overall abundance of the element; and overall size of the geographic range. Additional considerations include quality of the occurrences, ecological fragility, threats from human activity, and difficulty in providing appropriate management.
The State or "Subnational" (S) Rank reflects the conservation status of a species from a local perspective, characterizing the relative rarity or imperilment of the species within the state of New Mexico. The status of an element is indicated on a scale of one to five; the score is based on the estimated number of extant occurrences of the element and other factors such as trends, threats, and abundance.
Heritage Ranks and Status Designations
Heritage ranks are independent of Federal and State status designations and, as such, they carry no formal role in protecting species. They are, however, useful in determining what species might warrant special consideration whether or not they currently have formal protection. Species with high heritage ranks (G1-3 and/or S1-3) are often species of concern for one or more management authorities. Heritage ranks are more dynamic than status designations and may better reflect the current biological condition of species irrespective of political concerns. Species may also be of high rank when the current state of knowledge suggests they might be vulnerable to extinction or extirpation, but more information is needed.