Western skink (Eumeces skiltonianus) COSEWIC assessment and status report: chapter 8

Limiting Factors

Factors limiting the occurrence and range expansion of E. skiltonianus in Canada are both natural and climate-related or related to human activities. The species reaches the northern extremity of its distribution in southern British Columbia. The dependence of E. skiltonianus on relatively warm, dry conditions probably restricts its distribution and range expansion in the province. Locally, critical habitat features that likely govern patterns of distribution and abundance include openings along south-facing slopes for nesting, herbaceous vegetation cover for foraging and predator avoidance, loose soil for burrow excavation, and the presence of rocks and downed logs for shelter.

Habitat fragmentation caused by human activities and developments is probably a major factor limiting the distribution and persistence of populations of E. skiltonianus within suitable areas. Habitat fragmentation is likely to curtail movements between habitat patches and may result in reduced rates of colonization of new areas and recolonization of areas where populations have been extirpated due to other causes and stochastic fluctuations. The importance of such metapopulation processes to E. skiltonianus have not been studied but may be significant in light of the presumably poor dispersal ability and wide population fluctuations of these small lizards.

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