Activity and Habitat Use of Prairie Skinks, Eumeces septentrionalis, in Manitob

The northern prairie skink, Eumeces septentrionalis septentrionalis , is an endangered species in Manitoba, the only province where they are known to occur in Canada. Southwestern Manitoba forms the northernmost limit of their global distribution, with the nearest populations of this species occurring over 200km further south in the United States. The highly isolated nature of Manitoba populations increases the risk of sudden and irreversible population declines with no chance of repopulation from areas outside the province. Long-term species viability is further threatened by the continued loss of native mixed grass prairie in the region, the habitat most heavily used by the northern prairie skink. Current land management activities such as fire suppression and the elimination of grazing may continue to encourage the spread of aspen parkland at the expense of native grasslands. This study was necessary to expand our knowledge about the ecology and habitat requirements of the northern prairie skink in Manitoba. A stratified sampling design with coverboards was used to determine which habitats are being used by northern prairie skinks in Spruce Woods Provincial Park. Skink activity was highest during the breeding season, with a short burst of activity by all cohorts at the end of July. Snout-vent lengths and masses of this population are similar to those found in Minnesota and other regions of Manitoba. Moderate levels of tail loss, 11-31% of captured males and females respectively, indicated predation pressure was low compared to other studies. Skinks were primarily found in open native mixed-grass prairie dominated by the species Bouteloua gracilis, Andropogon scoparius and Carex species. Sites occupied by skinks supported relatively high prey populations (e.g. crickets) and were warmer than forested sites, thus providing suitable thermoregulatory conditions. Within mixed-grass prairies, skinks used cover provided by native grasses to thermoregulate while hiding from predators. Using radiotelemetry, skink movements up to 16 m along stabilized, transverse dunes were observed. These movements are further than reported elsewhere and may be a result of the need to move farther to obtain enough food, find mates and/or shelter at the northern limit of prairie skink range. Aspen encroachment and the accumulation of grass litter affected the microclimates available to northern prairie skinks, therefore altering activity patterns and population viability. Management (e.g. fire) to control both aspen encroachment and grass litter accumulation is needed to maintain habitat critical to the survival of the northern prairie skink in Manitoba.