Rank & Status Definitions
The Mississippi Natural Heritage Program uses the Heritage ranking system developed by The Nature Conservancy and maintained by NatureServe. Each species is assigned two ranks; one representing its range wide or global status (GRANK), and one representing its status in the state (SRANK). In addition, certain species may possess a legal protection status.
State ranks denote a species’ conservation status in Mississippi on a five-point scale from critically imperiled (1) to secure (5). They are assigned by Heritage Program Staff and are denoted by an “S” followed by a number or character. These ranks should not be interpreted as legal designations.
SX – Presumed Extirpated – Species or ecosystem is believed to be extirpated from Mississippi. Not located despite intensive searches of historical sites and other appropriate habitat, and virtually no likelihood that it will be rediscovered.
SH – Possibly Extirpated – Known from only historical records in Mississippi, but still some home of rediscovery. There is evidence that the species or ecosystem may no longer be present in the jurisdiction, but not enough to state this with certainty.
S1 – Critically Imperiled in Mississippi because of extreme rarity (5 or fewer occurrences or very few remaining individuals or acres) or because of some factor(s) such as very steep declines making it especially vulnerable to extirpation.
S2 – Imperiled in Mississippi because of rarity (6 to 20 occurrences or few remaining individuals or acres) or because of some factor(s) making it vulnerable to extirpation.
S3 – Vulnerable in Mississippi due to a restricted range (on the order of 21 to 100 occurrences), relatively few populations or occurrences, recent and widespread declines, or other factors making it vulnerable to extirpation.
S4 – Apparently Secure – Uncommon but not rare in Mississippi; some cause for long-term concern due to declines or other factors (more than 101 occurrences).
S5 – Secure – Common, widespread, and abundant in Mississippi.
SU – Unrankable – Currently unrankable due to lack of information or due to substantially conflicting information about status or trends.
SNR – Unranked – Conservation status not yet assessed.
SNA – Not Applicable – A conservation status rank is not applicable because the species or ecosystem is not a suitable target for conservation activities (e.g., long distance aerial and aquatic migrants, hybrids without conservation value, and non-native species or ecosystems.
S#S# – Range Rank - A numeric range rank (e.g., S2S3) is used to indicate any range of uncertainty about the status of the species or community.
S#? – Inexact Numeric Rank – Denotes inexact numeric rank.
S#B – Breeding – Conservation status refers to the breeding population of the species in Mississippi.
S#N – Non-breeding – Conservation status refers to the non-breeding population of the species in Mississippi.
S#M – Migrant species occurring regularly on migration at particular staging areas or concentration spots where the species might warrant conservation attention. Conservation status refers to the aggregating transient population of the species in Mississippi.
SP – Potential that species occurs in Mississippi but no extant or historic occurrences are accepted.
Global ranks follow the same principle as state ranks, but refer to a species’ rarity throughout its total range. They are assigned by the NatureServe Network and are denoted with a “G” followed by a number or character as described above. However, there are two additional definitions:
G#Q – Questionable taxonomy that may reduce conservation priority – Distinctiveness of this entity as a species, subspecies, or ecosystem is questionable. Resolution of this uncertainty may result in the change from a species to a subspecies or vice versa.
G#T# – Infraspecific Taxon (trinomial) – The status of infraspecific taxa (subspecies or varieties) are indicated by a “T-rank” which is appended to the species’ global rank. It denotes the rarity of the subspecies. For example, a critically imperiled subspecies of an otherwise widespread and common species would be a G5T1.
Federal and State Statuses
Federal and State statuses are legal protection designations for certain species. A federal listing status is determined by U.S. Fish & Wildlife as part of the 1974 Endangered Species Act while a state listing status is determined by the Mississippi Commission on Wildlife, Fisheries, & Parks. Note that plants receive no formal legal protection by state law in Mississippi other than that provided for in the trespass laws. Abbreviations used are defined below.
LE – Listed Endangered - A species which is in danger of extinction throughout all or a significant portion of its range.
LT – Listed Threatened - A species which is likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range.
SAE – Endangered due to similarity of appearance - A species that is endangered due to similarity of appearance with another listed species and is listed for its protection.
SAT – Threatened due to similarity of appearance - A species that is threatened due to similarity of appearance with another listed species and is listed for its protection.
PS – Partial Status - A species is listed in parts of its range and not in others; or, one or more subspecies or varieties are listed, while the others are not listed.
PE – Proposed Endangered – Species proposed for official listing as endangered.
PT – Proposed Threatened – Species proposed for official listing as threatened.
C – Candidate Species - A species under consideration for official listing for which there is sufficient information to support proposing to list as endangered or threatened.
SC – Species of Concern – A species that has not been petitioned or been given LE, LT, or C status but has been identified as important to monitor and in need of conservation actions.