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Florida State University
Florida Resources and
Environmental Analysis Center
at the Institute of Science
and Public Affairs

NatureServe
A Network Connecting Science with Conservation




Explanations and Definitions of Rank and Status

Elements and Element Occurrences

An element is any exemplary or rare component of the natural environment, such as a species, natural community, bird rookery, spring, sinkhole, cave, or other ecological feature.

An element occurrence (EO) is an area of land and/or water in which a species or natural community is, or was, present. An EO should have practical conservation value for the Element as evidenced by potential continued (or historical) presence and/or regular recurrence at a given location.

 

Element Ranking and Legal Status

Using a ranking system developed by NatureServe and the Natural Heritage Program Network, the Florida Natural Areas Inventory assigns two ranks for each element.  The global rank is based on an element's worldwide status; the state rank is based on the status of the element in Florida. Element ranks are based on many factors, the most important ones being estimated number of Element Occurrences (EOs), estimated abundance (number of individuals for species; area for natural communities), geographic range, estimated number of adequately protected EOs, relative threat of destruction, and ecological fragility.

FNAI GLOBAL ELEMENT RANK

G1  =   Critically imperiled globally because of extreme rarity (5 or fewer occurrences or less than 1000 individuals) or because of extreme vulnerability to extinction due to some natural or man-made factor.

G2  =   Imperiled globally because of rarity (6 to 20 occurrences or less than 3000 individuals) or because of vulnerability to extinction due to some natural or man-made factor.

G3  =   Either very rare and local throughout its range (21-100 occurrences or less than 10,000 individuals) or found locally in a restricted range or vulnerable to extinction from other factors.

G4  =   Apparently secure globally (may be rare in parts of range).

G5  =   Demonstrably secure globally.

GH  =   Of historical occurrence throughout its range, may be rediscovered (e.g., ivory-billed woodpecker).

GX  =   Believed to be extinct throughout range.

GXC  =   Extirpated from the wild but still known from captivity or cultivation.

G#?  =   Tentative rank (e.g., G2?).

G#G#  =   Range of rank; insufficient data to assign specific global rank (e.g., G2G3).

G#T#  =   Rank of a taxonomic subgroup such as a subspecies or variety; the G portion of the rank refers to the entire species and the T portion refers to the specific subgroup; numbers have same definition as above (e.g., G3T1).

G#Q  =   Rank of questionable species - ranked as species but questionable whether it is species or subspecies; numbers have same definition as above (e.g., G2Q).

G#T#Q  =   Same as above, but validity as subspecies or variety is questioned.

GU  =   Unrankable; due to a lack of information no rank or range can be assigned (e.g., GUT2).

GNA  =   Ranking is not applicable because the element is not a suitable target for conservation (e.g. a hybrid species).

GNR  =   Element not yet ranked (temporary).

GNRTNR  =   Neither the element nor the taxonomic subgroup has yet been ranked.

 

FNAI STATE ELEMENT RANK

S1  =   Critically imperiled in Florida because of extreme rarity (5 or fewer occurrences or less than 1000 individuals) or because of extreme vulnerability to extinction due to some natural or man-made factor.

S2  =   Imperiled in Florida because of rarity (6 to 20 occurrences or less than 3000 individuals) or because of vulnerability to extinction due to some natural or man-made factor.

S3  =   Either very rare and local in Florida (21-100 occurrences or less than 10,000 individuals) or found locally in a restricted range or vulnerable to extinction from other factors.

S4  =   Apparently secure in Florida (may be rare in parts of range).

S5  =   Demonstrably secure in Florida.

SH  =   Of historical occurrence in Florida, possibly extirpated, but may be rediscovered (e.g., ivory-billed woodpecker).

SX  =   Believed to be extirpated throughout Florida.

SU  =   Unrankable; due to a lack of information no rank or range can be assigned.

SNA  =   State ranking is not applicable because the element is not a suitable target for conservation (e.g. a hybrid species).

SNR  =   Element not yet ranked (temporary).  

 

FEDERAL LEGAL STATUS

Legal status information provided by FNAI for information only.  For official definitions and lists of protected species, consult the relevant federal agency.

Definitions derived from U.S. Endangered Species Act of 1973, Sec. 3. Note that the federal status given by FNAI refers only to Florida populations and that federal status may differ elsewhere.

C  =   Candidate species for which federal listing agencies have sufficient information on biological vulnerability and threats to support proposing to list the species as Endangered or Threatened.

E  =   Endangered: species in danger of extinction throughout all or a significant portion of its range.

E, T  =   Species currently listed endangered in a portion of its range but only listed as threatened in other areas

E, PDL  =   Species currently listed endangered but has been proposed for delisting.

E, PT  =   Species currently listed endangered but has been proposed for listing as threatened.

E, XN  =   Species currently listed endangered but tracked population is a non-essential experimental population.

T  =   Threatened: species likely to become Endangered within the foreseeable future throughout all or a significant portion of its range.

PE = Species proposed for listing as endangered

PS = Partial status: some but not all of the species’ infraspecific taxa have federal status

PT = Species proposed for listing as threatened

SAT  =   Treated as threatened due to similarity of appearance to a species which is federally listed such that enforcement personnel have difficulty in attempting to differentiate between the listed and unlisted species.

SC  =   Not currently listed, but considered a “species of concern” to USFWS.

STATE LEGAL STATUS

Provided by FNAI for information only.  For official definitions and lists of protected species, consult the relevant state agency.

Animals:  Definitions derived from “Florida’s Endangered Species and Species of Special Concern, Official Lists” published by Florida Fish and Wildlife Conservation Commission, 1 August 1997, and subsequent updates.

C = Candidate for listing at the Federal level by the U. S. Fish and Wildlife Service

FE  =   Listed as Endangered Species at the Federal level by the U. S. Fish and Wildlife Service

FT  =   Listed as Threatened Species at the Federal level by the U. S. Fish and Wildlife Service

FXN  =   Federal listed as an experimental population in Florida

FT(S/A)  =   Federal Threatened due to similarity of appearance

ST  =   State population listed as Threatened by the FFWCC.  Defined as a species, subspecies, or isolated population which is acutely vulnerable to environmental alteration, declining in number at a rapid rate, or whose range or habitat is decreasing in area at a rapid rate and as a consequence is destined or very likely to become an endangered species within the foreseeable future.

SSC  =   Listed as Species of Special Concern by the FFWCC.  Defined as a population which warrants special protection, recognition, or consideration because it has an inherent significant vulnerability to habitat modification, environmental alteration, human disturbance, or substantial human exploitation which, in the foreseeable future, may result in its becoming a threatened species.  (SSC* for Pandion haliaetus (Osprey) indicates that this status applies in Monroe county only.)

N  =   Not currently listed, nor currently being considered for listing.

Plants:  Definitions derived from Sections 581.011 and 581.185(2), Florida Statutes, and the Preservation of Native Flora of Florida Act, 5B-40.001. FNAI does not track all state-regulated plant species; for a complete list of state-regulated plant species, call Florida Division of Plant Industry, 352-372-3505 or see: http://www.doacs.state.fl.us/pi/.

E  =   Endangered: species of plants native to Florida that are in imminent danger of extinction within the state, the survival of which is unlikely if the causes of a decline in the number of plants continue; includes all species determined to be endangered or threatened pursuant to the U.S. Endangered Species Act.

T  =   Threatened: species native to the state that are in rapid decline in the number of plants within the state, but which have not so decreased in number as to cause them to be Endangered.

N  =   Not currently listed, nor currently being considered for listing.

 

Element Occurrence Ranking

FNAI ranks of quality of the element occurrence in terms of its viability (EORANK).  Viability is estimated using a combination of factors that contribute to continued survival of the element at the location. Among these are the size of the EO, general condition of the EO at the site, and the conditions of the landscape surrounding the EO (e.g. an immediate threat to an EO by local development pressure could lower an EO rank).

A  =  Excellent estimated viability

A?  =  Possibly excellent estimated viability

AB  =  Excellent or good estimated viability

AC  =  Excellent, good, or fair estimated viability

B  =   Good estimated viability

B?  =   Possibly good estimated viability

BC  =   Good or fair estimated viability

BD  =   Good, fair, or poor estimated viability

C  =   Fair estimated viability

C?  =   Possibly fair estimated viability

CD  =   Fair or poor estimated viability

D  =   Poor estimated viability

D?  =   Possibly poor estimated viability

E  =   Verified extant (viability not assessed)

F  =   Failed to find

H  =   Historical

NR  =  Not ranked, a placeholder when an EO is not (yet) ranked.

U  =   Unrankable

X  =   Extirpated

 

*For additional detail on the above ranks see: http://www.natureserve.org/explorer/eorankguide.htm

 

FNAI also uses the following EO ranks:

H?  =   Possibly historical

F?  =   Possibly failed to find

X?  =   Possibly extirpated

 

The following offers further explanation of the H and X ranks as they are used by FNAI:

The rank of H is used when there is a lack of recent field information verifying the continued existence of an EO, such as (a) when an EO is based only on historical collections data; or (b) when an EO was ranked A, B, C, D, or E at one time and is later, without field survey work, considered to be possibly extirpated due to general habitat loss or degradation of the environment in the area.  This definition of the H rank is dependent on an interpretation of what constitutes "recent" field information. Generally, if there is no known survey of an EO within the last 20 to 40 years, it should be assigned an H rank.  While these time frames represent suggested maximum limits, the actual time period for historical EOs may vary according to the biology of the element and the specific landscape context of each occurrence (including anthropogenic alteration of the environment).  Thus, an H rank may be assigned to an EO before the maximum time frames have lapsed. Occurrences that have not been surveyed for periods exceeding these time frames should not be ranked A, B, C, or D.  The higher maximum limit for plants and communities (i.e., ranging from 20 to 40 years) is based upon the assumption that occurrences of these elements generally have the potential to persist at a given location for longer periods of time. This greater potential is a reflection of plant biology and community dynamics. However, landscape factors must also be considered. Thus, areas with more anthropogenic impacts on the environment (e.g., development) will be at the lower end of the range, and less-impacted areas will be at the higher end. 

The rank of X is assigned to EOs for which there is documented destruction of habitat or environment, or persuasive evidence of eradication based on adequate survey (i.e., thorough or repeated survey efforts by one or more experienced observers at times and under conditions appropriate for the Element at that location).