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Drymarchon couperi

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA REPTILIA SQUAMATA COLUBRIDAE

Scientific Name: Drymarchon couperi
Species Authority: (Holbrook, 1842)
Common Name(s):
English Eastern Indigo Snake
Synonym(s):
Drymarchon corais subspecies couperi (Holbrook, 1842)
Taxonomic Notes: Drymarchon couperi was proposed as a distinct species by Collins (1991), based on previously published (but unspecified) morphological differences and application of the evolutionary species concept. Recent checklists (e.g., Crother et al. 2000, Collins and Taggart 2002) listed couperi as a species, although no new data supporting the split have been presented.

Wuster et al. (2001) described a new species of Drymarchon from northwestern Venezuela, bringing the species total for the genus to four (five if couperi is recognized as a species). Wuster et al. (2001) did not present data on D. couperi but nevertheless accepted it as a distinct species, based on apparently consistent differences in labial scalation (Smith, 1941). They noted, however, that further study is needed to confirm the taxonomic status of D. couperi.

This database accepts Drymarchon couperi as a species, based on similar treatment in most relevant recent literature.

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2007
Date Assessed: 2007-03-01
Assessor(s): Hammerson, G.A.
Reviewer(s): Cox, N., Chanson, J.S. & Stuart, S.N. (Global Reptile Assessment Coordinating Team)
Justification:
Listed as Least Concern in view of the fairly large range and area of occupancy and presumed large population size. Many subpopulations exist, but a large proportion may be of low viability. Area of occupancy and abundance likely are declining but probably not fast enough for listing in a more threatened category.
History:
1996 Not Evaluated
1994 Vulnerable (Groombridge 1994)
1990 Vulnerable (IUCN 1990)
1988 Vulnerable (IUCN Conservation Monitoring Centre 1988)
1986 Vulnerable (IUCN Conservation Monitoring Centre 1986)

Geographic Range [top]

Range Description: This species is endemic to the southeastern United States. Its historical range extended throughout the lower Coastal Plain of the southeastern United States, from southern South Carolina through Georgia and Florida to the Florida Keys, and west to southern Alabama and perhaps southeastern Mississippi. Its current range includes southern Georgia (most common in the southeast; see Diemer and Speake 1983) and Florida (widely distributed throughout the state, south to the Keys, though perhaps very localized in the panhandle; Moler 1985, 1992; see also Ballard 1992). The species is apparently very rare or extirpated in Alabama, Mississippi, and South Carolina. Recent reintroductions have been made in Florida, Alabama, Georgia, South Carolina, and Mississippi. One reintroduced population may be thriving in Covington County, Alabama.
Countries:
Native:
United States
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: This species is represented by many occurrences or subpopulations, but many of these may not represent populations with good viability. This species is extant in many sites in southeastern Georgia; Diemer and Speake (1983) mapped well over 100 locations in perhaps several dozen counties. In Florida, the snake is known from about 400 locations, though most records represent single specimens. The total adult population size is unknown but probably exceeds 10,000 (conservatively assuming a density of at least 1 adult per sq. kilometer in an area of occupancy of at least 20,000 sq. km). The number of occurrences and range have been reduced significantly in the past 40 years; the species underwent a population decline in the 1960s and 1970s. USFWS (1990) categorized the status as "declining." Based on current rates of habitat destruction and degradation, USFWS (1998) surmised that the range-wide population is declining, although the rate of decline is uncertain.
Population Trend: Decreasing

Habitat and Ecology [top]

Habitat and Ecology: Its habitat includes sandhill regions dominated by mature longleaf pines, turkey oaks, and wiregrass; flatwoods; most types of hammocks; coastal scrub; dry glades; palmetto flats; prairie; brushy riparian and canal corridors; and wet fields (Matthews and Moseley 1990, Tennant 1997, Ernst and Ernst 2003). Occupied sites are often near wetlands and frequently are in association with Gopher Tortoise burrows. Pineland habitat is maintained by periodic fires. Viable populations of this species require relatively large tracts of suitable habitat. Refuges include tortoise burrows, stump holes, land crab burrows, armadillo burrows, or similar sites. Eggs may be laid in gopher (Geomys) burrows (Ashton and Ashton 1981). See USFWS (1998) for further information.
Systems: Terrestrial

Threats [top]

Major Threat(s): Decline is attributed to loss of mature longleaf pine habitat (e.g., conversion to slash and sand pine plantation, urbanization, citrus, mining, etc.), commercial collecting for pet trade (now illegal and has declined), and former widespread gassing of tortoise burrows (to collect rattlesnakes) (USFWS 1998). In northern Florida and adjacent southern Alabama and Georgia, important refugia have been lost with the decline in the Gopher Tortoise population (fewer burrows available) and the removal of stumps by the resinous wood industry; elsewhere, habitat fragmentation is a problem (Moler 1992).

Conservation Actions [top]

Conservation Actions: Several occurrences are on managed areas (federal, state, and private), but these are still subject to some unauthorized collection. Many managed areas are too small to support a viable population by themselves.

Citation: Hammerson, G.A. 2007. Drymarchon couperi. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 29 August 2014.
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