Prairie skink (Eumeces septentrionalis) COSEWIC assessment and status report: chapter 7

Population Sizes and Trends

An accurate survey of the present number and size of populations of Prairie Skinks in Canada is not available. For example, of the 21 “populations” described in the first COSEWIC report, over 60% of them have not been re-visited in over a decade (Table 1). Density estimates of 63-231 individuals per hectare have been made for old fields in Minnesota (Pitt 2001). Areas where Prairie Skinks are relatively easy to catch are habitat patches with abundant artificial cover. The number or density of skinks in such areas is likely artificially high. Skinks likely occur in areas without artificial cover, constructing burrows under clumps of vegetation or under woody debris, but they are almost impossible to census in such areas. Skink density also appears to be higher on south facing ridges and slopes.

Within the Lauder Sandhills, it was estimated that only approximately 2500 ha of the 60 000 ha area was potential skink habitat (Bredin 1989). The amount of suitable habitat is difficult to quantify because the habitat occurs in small patches not readily detected by remote sensing (J. Duncan pers. comm., May 2004). Skinks were only discovered on <1 ha in the Lauder Sandhills in 1985 and at that time it was presumed they were more widespread in the area. However, subsequent surveys by Errol Bredin and Ken De Smet of the Manitoba Conservation Data Centre in 2001 and 2002 confirmed that skinks were present only in the original area surveyed in 1985. The placement of cover objects in many other locations within the Lauder Sandhills failed to locate any additional sites with skinks. It is therefore highly probable that skinks are limited to the one site (<1 ha). It is uncertain if skinks were ever more widespread throughout the Lauder Sandhills. In any case, this population is at risk of extinction because of isolation.

Table 1. Historic records of Prairie Skinks
ID # Location Most Recent Observation Observer
1 N side of Assiniboine R, W of PR 242
1988
Bredin, E., pers. com.
2 NE of #19
1988
Bredin, E., pers. com.
3 Mouth of Cypress R
1988
Bredin, E., pers. com.
4 Approx 4 km E of Steel Ferry Overlook
2002
Fuerst, G., pers. com.
5 12 km SW of Carberry
1999
Bredin, E., pers. com.
6 10 km NW of Sydney
1988
Bredin, E., pers. com.
7 4 km W, 5 km N of Sydney
1988
Bredin, E., pers. com.
8 3.5 km W, 3.2 km N of Sydney
1988
Bredin, E., pers. com.
9 2.4 km S, 3.2 km W of Edrans on PR 352
1988
Bredin, E., pers. com.
10 Local Dump about 5 km E of Wellwood
2002
Fuerst, G., pers. com.
11 3.5 km NE of Glenboro
1988
Bredin, E., pers. com.
12 Bald Hills area
1995
Bredin, E., pers. com.
13 Spruce Woods Provincial Park E. of Hwy #5
2003
Scott, J., pers. com.
14 Spruce Woods Provincial Park E. of Hwy #5
2003
Scott, J., pers. com.
15 Spruce Woods Provincial Park E. of Hwy #5
2003
Scott, J., pers. com.
16 Spruce Woods Provincial Park E. of Hwy #5
2003
Scott, J., pers. com.
17 Spruce Woods Provincial Park E. of Hwy #5
2003
Scott, J., pers. com.
18 Spruce Woods Provincial Park E. of Hwy #5
2003
Scott, J., pers. com.
19 Approx. 6 km N of Epinette Creek on Hwy #5
2002
Fuerst, G., pers. com.
20 Approx. 6 km N of Epinette Creek on Hwy #5
2002
Fuerst, G., pers. com.
21 11 km SW of Carberry
1999
Bredin, E., pers. com.
22 10 km S, 7 km E of Neepawa
1988
Bredin, E., pers. com.
23 6 km SW of Neepawa
1988
Bredin, E., pers. com.
24 Shilo Military Base
2001
Fuerst, G., pers. com.
25 Approx. 7 km W of Carberry
2002
Fuerst, G., pers. com.
26 Approx. 7 km W of Carberry
2002
Fuerst, G., pers. com.
27 9 km W of Carberry
2003
Bredin, E., pers. com.
28 7.2 km W of Carberry
2000
Bredin, E., pers. com.
29 E of junction of Souris & Assiniboine R
1988
Bredin, E., pers. com.
30 Onah Station
2001
Bredin, E., pers. com.
31 CFB Shilo dump
1988
Bredin, E., pers. com.
32 Camp Hughes
1988
Bredin, E., pers. com.
33 6 km S of CFB Shilo
2001
Bredin, E., pers. com.
34 Lauder Sandhills
2002
Bredin, E., pers. com.

It is unclear how well connected populations are in the Carberry Sandhills. Long term monitoring of various sites suggests that either populations have continued to persist over the last 20 years or that re-colonizations occur quickly. The latter seems less likely given the species’ limited dispersal ability. Egg production appears to be dramatically reduced in very dry years (Bredin 1988), although it is unclear what effect this has on demography. Presumably a number of exceptionally dry years in a row would reduce population levels and it is possible that a lengthy drought could eliminate populations.

Prairie Skinks are not territorial and males are only aggressive to other males during the breeding season. Skinks are frequently caught repeatedly under the same cover object over time and typical home range is likely only a few square meters, although individuals may make some home range shifts over the course of the season. Given the general secretiveness of skinks they are usually not directly persecuted by humans.

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