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Emydoidea blandingii

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA REPTILIA TESTUDINES EMYDIDAE

Scientific Name: Emydoidea blandingii
Species Authority: (Holbrook, 1838)
Common Name(s):
English Blanding's Turtle
Synonym(s):
Cistuda blandingii Holbrook, 1838
Emys blandingii (Holbrook, 1838)
Taxonomic Notes: The species blandingii has generally been placed in Emydoidea in recent years, but has also been argued to belong in the genus Emys, based on molecular phylogeny results.

Assessment Information [top]

Red List Category & Criteria: Endangered A2cde+4ce ver 3.1
Year Published: 2013
Date Assessed: 2010-08-01
Assessor(s): van Dijk, P.P. & Rhodin, A.G.J.
Reviewer(s): Horne, B.D., Mittermeier, R.A., Philippen, H.-D., Quinn, H.R., Rhodin, A.G.J. & Vogt, R.C
Justification:
Emydoidea blandingii is evaluated as Endangered A2cde+A4ce, given extensive slow declines of most of its populations from habitat loss and direct removal, accidental mortality and increased predation, and its very long generation time of 36–47 years and slow rate of potential recovery. The species was previously listed as LR/nt.

Geographic Range [top]

Range Description: Emydoidea blandingii inhabits the Great Lakes region of Canada and the United States, the upper Mississippi basin, and the Niobrara and Platte Rover Systems of the Missouri; scattered populations occur in the lower Hudson Valley of New York, in the eastern Massachusetts (SE New Hampshire) southern Maine area, and in Nova Scotia (Iverson 1992, Congdon et al. 2008).
Countries:
Native:
Canada (Nova Scotia, Ontario, Québec); United States (Illinois, Indiana, Iowa, Maine, Massachusetts, Michigan, Minnesota, Missouri, Nebraska, New Hampshire, New York, Ohio, Pennsylvania, South Dakota)
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population:

Populations of Blanding's Turtle are often small and localized, with populations of a few dozen or hundred turtles, and densities ranging from 0.02 animals per hectare in Maine to 28/ha in Wisconsin, 55/ha in Missouri, and up to 57/ha in Nebraska. The largest known population, in Nebraska, is estimated at over 130,000 animals, excluding hatchlings and yearlings (Lang 2004). In contrast, Pennsylvania populations may total a few dozen individuals. Populations in Illinois and Ohio are perceived to be in ongoing decline, possibly associated with increased predation by raccoons (D. Mifsud, pers. comm. 2009).

Some populations appear stable over time, while others were documented as declining (Brodman et al. 2002, Smith et al. 2006). Summaries of these can be found in Congdon et al. (2008) and Ernst and Lovich 2009.

Participants at the MidWest USA Turtle RL WS estimated that 30–50% of suitable habitat and the populations they contained have been lost in recent decades, while many remaining populations have reduced in size.

Population Trend: Decreasing

Habitat and Ecology [top]

Habitat and Ecology: Blanding's Turtle uses a variety of permanent and temporary wetland habitats, with a preference for shallow clear standing water with abundant aquatic vegetation, but can be found in almost any waterbody in their area. The animals are highly mobile and move extensively between wetlands; nesting occurs in open grasslands, often well away from water. Animals leave strong scent trails, increasing their vulnerability to raccoon and fox predation. The species feeds mainly on crayfish and other small animal prey, but also scavenges and takes plant material and seeds.

Males reach 28 cm carapace length (CL), females 22 cm CL. Maturity is reached at about 12 years (20 cm CL) in males, and at 14–20 years (16–19 cm CL) in females. Longevity can be at least 77 years in the wild. Blanding's Turtle has been subject of arguably the most detailed population dynamics analysis of any turtle, documenting that animals mature at the age of 14 at the earliest, and generation times were calculated to vary between 36 and 47 years (Congdon et al. 2000, Ernst and Lovich 2009).

Females produce one or two clutches of 8–15 eggs (range 3–22, substantial geographic variation) in a reproductive year, but only half the females in a population may reproduce in a given year. Incubation takes about 82–96 (range 65–128) days, with substantial geographic variation. Hatchlings measure about 33 mm.

[Reviews available in Congdon et al. (2008), and Ernst and Lovich (2009)]
Systems: Terrestrial; Freshwater

Use and Trade [top]

Use and Trade: Blanding's Turtle is not consumed and occurs in the commercial pet trade at relatively low but persistent numbers in the high-end pet trade in recent years, including export to Japan. Offers include lots of multiple adult females suspected to be caught from the wild.

Threats [top]

Major Threat(s):

Blanding's Turtles have been reported as being impacted by road mortality and collection for trade. They also at least locally from habitat degradation, fragmentation and destruction, and increased predation of eggs, young and possibly adults from subsidized predators (i.e., unnaturally large populations of predators subsidized by easily available resources near human settlements), but little quantitative data on the severity of these factors appears available.

Road mortality risk increases with progressive expansion and increased density of rural road networks.

Blanding’s Turtle is the second commonest turtle species in bycatch of the commercial trapping of snapping turtles using baited traps, and a ready market exists (Harding, pers comm. Aug 2009).

Given its particular population dynamics, slightly increased rates of loss of juveniles and adults significantly affects a population.

Conservation Actions [top]

Conservation Actions: Blanding's Turtle is listed as Endangered (Nova Scotia) and Threatened (Great Lakes/St. Lawrence) under Canada's Species at Risk Act.
It is protected under State legislation and regulations in Massachusetts, New York, and presumably other States.

The species occurs in a number of protected areas across its range, including a very large population in Nebraska. In Michigan, management of wetlands over five acres has been transferred from State to Federal administration. Conservation action programs for the species have been developed in several US States and in Nova Scotia.

Immediate conservation needs include:
  1. Methods to reduce road mortality (e.g., fencing and road passages);
  2. Elimination of commercial collecting;
  3. Protection of large resident wetland areas and smaller ephemeral wetlands;
  4. Protection and management of adjacent terrestrial areas used for nesting and as corridors for movements among wetlands;
  5. Research on risks associated with the timing and duration of terrestrial movements of both sexes
  6. Where necessary, removal of nest predators
(Congdon et al. 2008)

Bibliography [top]

Congdon, J.D., Graham, T.E., Herman, T.B., Lang, J.W., Pappas, M.J., & Brecke, B.J. 2008. Emydopidea blandingii (Holbrook 1838) - Blanding's Turtle. Chelonian Research Monographs 5: 015.1-015.12.

Ernst, C.H. and Lovich, J.E. 2009. Turtles of the United States and Canada. Second edition. Johns Hopkins University Press, Baltimore.

IUCN. 2011. IUCN Red List of Threatened Species (ver. 2011.1). Available at: http://www.iucnredlist.org. (Accessed: 16 June 2011).

Iverson, J.B. 1992. A Revised Checklist with Distribution Maps of the Turtles of the World. Richmond, Indiana. (Privately published).


Citation: van Dijk, P.P. & Rhodin, A.G.J. 2013. Emydoidea blandingii. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 19 September 2014.
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