Prairie skink (Eumeces septentrionalis) COSEWIC assessment and status report: chapter 2

COSEWIC Executive Summary

Prairie Skink
Eumeces septentrionalis

Species information

The Prairie Skink (Scincidae: Eumeces septentrionalis) is a terrestrial lizard ranging from 25 mm (on hatching) to 85 mm snout-vent length (SVL) (maximum adult size). Prairie Skinks are brown with 4 pale longitudinal stripes. Juveniles are distinguished from adults by a bright blue tail. Adult males are distinguished from females by reddish orange on the head and throat during the breeding season.

Distribution

The Prairie Skink is limited to central Canada and the United States. Only the Northern Prairie Skink subspecies (E. s. septentrionalis) occurs in Canada, and it is limited to a small area (less than 1770 km²) of sandy soils in southwestern Manitoba. The nearest US population is more than 150 km to the south in northwestern Minnesota.

Habitat

The Prairie Skink is associated with mixed grass prairies. In Canada, it is limited to the Stockton Loamy Sand and Miniota Sands of the Carberry Hills of the Assiniboine Delta and a small disjunct population occurs on the Souris Sands of the Lauder Sandhills. The habitat in the Carberry Sandhills is naturally fragmented into three major units because of the Assiniboine River and the presence of other soil types not occupied by skinks. Sandy soils are required for nesting and overwintering habitat and summer burrows.

Biology

Females breed after their second or third winter and lay 4-18 eggs. Individuals breed annually but reproduction is significantly reduced in drought years. Eggs may be laid in communal nests with up to three nests under a single piece of cover. Eggs may also be laid underground away from cover objects. Females remain with the nest and reduce egg mortality by maintaining soil moisture. Prairie Skinks feed on insects and other small invertebrates. Movements are very limited and maximum length of a skink’s home range rarely exceeds 100 m. More than 7 months of the year are spent in hibernation.

Population sizes and trends

Although the number and size of populations are unknown, it is clear that suitable habitat is limiting and habitat loss is well-documented, extensive and ongoing. Thus it is very likely that populations have declined since the original report to COSEWIC in 1989. The remaining populations are severely fragmented by the patchy distribution of a suitable combination of sandy soils and mixed grass prairie. These suitable habitat patches are being destroyed by cultivation, invasion by a weedy exotic, Leafy Spurge (Euphorbia esula) and by succession to aspen forest so local populations are disappearing.

Limiting factors and threats

Prairie Skinks are limited to mixed grass prairie on sandy soils. This habitat is being lost to cultivation, urbanization, road construction and by fire suppression which leads to succession and invasion of Leafy Spurge and Aspen Parkland. Although much of the Prairie Skink’s habitat is publicly owned, this has not prevented succession or invasion by Leafy Spurge because most public lands are under fire suppression. The remaining mixed grass prairie habitat on the appropriate soil types is becoming increasingly fragmented as this habitat is being altered. In winters with little snow cover, frost may penetrate down to hibernacula and kill skinks.

Special significance of the species

The Prairie Skink is the only lizard species in Manitoba and one of only six native lizard species in Canada. It is disjunct from US populations and is likely to be genetically distinct from them.

Existing protection or other status designations

The Prairie Skink has the following natural heritage ranks: globally – G5; US – N5; Canada – N2; Manitoba – S2. It is not listed under the Manitoba Endangered Species Act, because it is not designated Threatened or Endangered. The skink and its habitat can be protected under the provincial Wildlife Act, which regulates human use of wildlife.

COSEWIC History

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) was created in 1977 as a result of a recommendation at the Federal-Provincial Wildlife Conference held in 1976. It arose from the need for a single, official, scientifically sound, national listing of wildlife species at risk. In 1978, COSEWIC designated its first species and produced its first list of Canadian species at risk. On June 5, 2003, the Species at Risk Act (SARA) was proclaimed. SARA establishes COSEWIC as an advisory body ensuring that species will continue to be assessed under a rigorous and independent scientific process.

COSEWIC Mandate

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) assesses the national status of wild species, subspecies, varieties, or other designatable units that are considered to be at risk in Canada. Designations are made on native species and include the following taxonomic groups: mammals, birds, reptiles, amphibians, fishes, arthropods, molluscs, vascular plants, mosses, and lichens.

COSEWIC Membership

COSEWIC comprises members from each provincial and territorial government wildlife agency, four federal organizations (Canadian Wildlife Service, Parks Canada Agency, Department of Fisheries and Oceans, and the Federal Biosystematic Partnership, chaired by the Canadian Museum of Nature), three nonjurisdictional members and the co-chairs of the species specialist and the Aboriginal Traditional Knowledge subcommittees. The committee meets to consider status reports on candidate species.

Definitions (after May 2004)

Species
Any indigenous species, subspecies, variety, or geographically defined population of wild fauna and flora.

Extinct (X)
A species that no longer exists.

Extirpated (XT)
A species no longer existing in the wild in Canada, but occurring elsewhere.

Endangered (E)
A species facing imminent extirpation or extinction.

Threatened (T)
A species likely to become endangered if limiting factors are not reversed.

Special Concern (SC)Footnote1
A species of special concern because of characteristics that make it particularly sensitive to human activities or natural events.

Not at Risk (NAR)Footnote2
A species that has been evaluated and found to be not at risk.

Data Deficient (DD)Footnote3
A species for which there is insufficient scientific information to support status designation.

Canadian Wildlife Service

The Canadian Wildlife Service, Environment Canada, provides full administrative and financial support to the COSEWIC Secretariat.

 

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