Global and State Element Ranks
The NJDEP's Natural Heritage
Program classifies and tracks rare species of odonates in New
Jersey to help prioritize conservation efforts and NJOS strongly
supports their efforts. They use standardized state and global rankings that were
developed by the Nature Conservancy and NatureServe. See below for the full definition of the ranks that
are used in this site.
The NJDEP Natural Heritage Program maintains
its own web site with information on their on-going programs and data on many other animals and plants. Click
explore their site but please, come back soon!
Following are the State element ranks used in tracking NJ odes
(and other organisms as well) Click
here for the Global ranks which
are also displayed in our database.
STATE ELEMENT RANKS
S1 Critically imperiled in New Jersey because of extreme rarity (5
or fewer occurrences or very few remaining individuals or acres).
Elements so ranked are often restricted to very specialized
conditions or habitats and/or restricted to an extremely small
geographical area of the state. Also included are elements which
were formerly more abundant, but because of habitat destruction or
some other critical factor of its biology, they have been
demonstrably reduced in abundance. In essence, these are elements
for which, even with intensive searching, sizable additional
occurrences are unlikely to be discovered.
S2 Imperiled in New Jersey because of rarity (6 to 20 occurrences).
Historically many of these elements may have been more frequent but
are now known from very few extant occurrences, primarily because of
habitat destruction. Diligent searching may yield additional
S3 Rare in state with 21 to 100 occurrences (plant species in this
category have only 21 to 50 occurrences). Includes elements which
are widely distributed in the state but with small
populations/acreage or elements with restricted distribution, but
locally abundant. Not yet imperiled in state but may soon be if
current trends continue. Searching often yields additional
S4 Apparently secure in state, with many occurrences.
S5 Demonstrably secure in state and essentially ineradicable under
SA Accidental in state, including species (usually birds or
butterflies) recorded once or twice or only at very great intervals,
hundreds or even thousands of miles outside their usual range; a few
of these species may even have bred on the one or two occasions they
were recorded; examples include European strays or western birds on
the East Coast and vice versa.
SE Elements that are clearly exotic in New Jersey including those
taxa not native to North America (introduced taxa) or taxa
deliberately or accidentally introduced into the State from other
parts of North America (adventive taxa). Taxa ranked SE are not a
conservation priority (viable introduced occurrences of G1 or G2
elements may be exceptions).
SH Elements of historical occurrence in New Jersey. Despite some
searching of historical occurrences and/or potential habitat, no
extant occurrences are known. Since not all of the historical
occurrences have been field surveyed, and unsearched potential
habitat remains, historically ranked taxa are considered possibly
extant, and remain a conservation priority for continued field work.
SP Element has potential to occur in New Jersey, but no occurrences
have been reported.
SR Elements reported from New Jersey, but without persuasive
documentation which would provide a basis for either accepting or
rejecting the report. In some instances documentation may exist, but
as of yet, its source or location has not been determined.
SRF Elements erroneously reported from New Jersey, but this error
persists in the literature.
SU Elements believed to be in peril but the degree of rarity
uncertain. Also included are rare taxa of uncertain taxonomical
standing. More information is needed to resolve rank.
SX Elements that have been determined or are presumed to be
extirpated from New Jersey. All historical occurrences have been
searched and a reasonable search of potential habitat has been
completed. Extirpated taxa are not a current conservation priority.
SXC Elements presumed extirpated from New Jersey, but native
populations collected from the wild exist in cultivation.
SZ Not of practical conservation concern in New Jersey, because
there are no definable occurrences, although the taxon is native and
appears regularly in the state. An SZ rank will generally be used
for long distance migrants whose occurrences during their migrations
are too irregular (in terms of repeated visitation to the same
locations), transitory, and dispersed to be reliably identified,
mapped and protected. In other words, the migrant regularly passes
through the state, but enduring, mapable element occurrences cannot
Typically, the SZ rank applies to a non-breeding population (N) in
the state - for example, birds on migration. An SZ rank may in a few
instances also apply to a breeding population (B), for example
certain lepidoptera which regularly die out every year with no
significant return migration.
Although the SZ rank typically applies to migrants, it should not be
used indiscriminately. Just because a species is on migration does
not mean it receives an SZ rank. SZ will only apply when the
migrants occur in an irregular, transitory and dispersed manner.
B Refers to the breeding population of the element in the state.
N Refers to the non-breeding population of the element in the state.
T Element ranks containing a "T" indicate that the infraspecific
taxon is being ranked differently than the full species. For example
Stachys palustris var. homotricha is ranked "G5T? SH" meaning the
full species is globally secure but the global rarity of the var.
homotricha has not been determined; in New Jersey the variety is
Q Elements containing a "Q" in the global portion of its rank
indicates that the taxon is of questionable, or uncertain
taxonomical standing, e.g., some authors regard it as a full
species, while others treat it at the subspecific level.
.1 Elements documented from a single location.
Note: To express uncertainty, the most likely rank is assigned and a
question mark added (e.g., G2?). A range is indicated by combining
two ranks (e.g., G1G2, S1S3).
NJOS note: Definitions for element ranks are after The Nature
Conservancy (1982: Chapter 4, 4.1-1 through 126.96.36.199-3).
GLOBAL ELEMENT RANKS
G1 Critically imperiled globally because of extreme rarity (5 or
fewer occurrences or very few remaining individuals or acres) or
because of some factor(s) making it especially vulnerable to
G2 Imperiled globally because of rarity (6 to 20 occurrences or few
remaining individuals or acres) or because of some factor(s) making
it very vulnerable to extinction throughout its range.
G3 Either very rare and local throughout its range or found locally
(even abundantly at some of its locations) in a restricted range
(e.g., a single western state, a physiographic region in the East)
or because of other factors making it vulnerable to extinction
throughout it's range; with the number of occurrences in the range
of 21 to 100.
G4 Apparently secure globally; although it may be quite rare in
parts of its range, especially at the periphery.
G5 Demonstrably secure globally; although it may be quite rare in
parts of its range, especially at the periphery.
GH Of historical occurrence throughout its range i.e., formerly part
of the established biota, with the expectation that it may be
GU Possibly in peril range wide but status uncertain; more
GX Believed to be extinct throughout range (e.g., passenger pigeon)
with virtually no likelihood that it will be rediscovered.
G? Species has not yet been ranked.