Prairie skink (Eumeces septentrionalis) COSEWIC assessment and status report: chapter 4

Distribution

Global range

The Prairie Skink occurs in a narrow band running from southern Manitoba south to coastal Texas (Figure 2). The Northern Prairie Skink is found in southern Manitoba south to extreme northeastern Oklahoma. Isolated populations occur in Wisconsin and Illinois.

Figure 2. North American distribution of Prairie Skink.

Figure 2.  North American distribution of Prairie Skink

Canadian range

In Canada, the Prairie Skink is limited to a small area of southwestern Manitoba disjunct from the US range (Cook 1964, Figure 3). The nearest US population is in northwestern Minnesota (Conant and Collins 1998), over 150 km from the Canadian populations. Within Manitoba, Prairie Skinks occur in two discrete areas. The majority of reports are within the sandy soils of the Upper Assiniboine Delta region (Carberry Sandhills). Most reports in this area are within 25 km of the town of Carberry (Figure 4).

Figure 3. Canadian distribution of Prairie Skink.

Figure 3. Canadian distribution of Prairie Skink

The northern limit of the range is approximately 6 km SW of Neepawa. The southern limit of the main population is 3.5 km NE of Glenboro, south of the Assiniboine River. The entire north-south range spans less than 70 km.

The eastern limit is roughly 12 km north of Treherne. The western limit of the main population is 6 km south of the Canadian Forces Base Shilo, along the sandy banks of the Assiniboine River. The east-west span of the main population is less than 75 km.

Within this region, Prairie Skinks are limited to areas of Stockton Loamy Sands (1400 km²) and Minota Sands (370 km²) (see technical summary, Bredin 1993). The total area of the main population (including areas not inhabited by skinks) is less than 1770 km² (Figure 3, 4).

Figure 4. Prairie Skink range in Manitoba. Hatched area is the extent of the suitable habitat for skinks. Dots are where Prairie Skinks have been found.

Figure 4. Prairie Skink range in Manitoba. Hatched area is the extent of the suitable habitat for skinks

Within the Carberry Sandhills Prairie Skink populations are naturally fragmented because of the distribution of the appropriate soil types. There are 3 main units of appropriate soil types:

  1. an area south of the Assiniboine River.
  2. an east-west unit running south of Carberry and north of the Assiniboine River. The Douglas Marsh extends more than 15 km into the east-west unit, separating northern and southern populations of skinks in this area.
  3. a north-south section north of Carberry consisting of patches of various sizes. A number of these patches are separated by a 20 km long band of clay loam (Wellwood Association) running north of Carberry.

There are also a number of small units of conducive soil, particularly east of Carberry, that are isolated or nearly isolated from other patches of Stockton Loamy Sand and Miniota Sand.

There is also a small disjunct population, in the Lauder Sandhills, west of the village of Hartney and approximately 90 km southwest of the Carberry Sandhills. This population is at the western and southern limit of the species in Canada. Surveys in 2001 and 2002 suggest this population is limited to one small area (< 1 ha) (E. Bredin, unpubl. data).

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