Site fidelity and habitat characteristics of woodland caribou (Rangifer tarandus) nursery areas in Wabakimi and Woodland Caribou provincial parks, Northern Ontario / by Natasha Lynn Carr.

Abstract

To prevent further range recession, habitat features essential to the life history requisites of woodland caribou (Rangifer tarandus caribou) such as calving and nursery areas need to be protected for the persistence of the species. Forest-dwelling woodland caribou may minimize predation risk during calving by either spacing out or spacing away from predators in the forest to calve on islands, wetlands, or shorelines. The first objective of this thesis was to determine if in fact the same female caribou was using the same area for calving and nursery activity year after year. Caribou faecal samples for DNA extraction were collected from nursery areas in 2 provincial parks in northern Ontario: Wabakimi and Woodland Caribou Provincial Parks. Extraction yield was poor in summer-collected faecal samples and site fidelity on a specific lake could not be demonstrated. However, differentiation of caribou DNA samples between parks suggests that caribou may be exhibiting female philopatry during the nursery period: female caribou typically return to a particular area year after year for calving and nursery activities (Brown and Theberge 1985, Gunn and Miller 1986, Fancy and Whitten 1991). Another objective was to determine the fine-scale characteristics of shoreline habitats used as calving and nursery areas by female woodland caribou in the 2 parks. Detailed vegetation and other site characteristics were measured at shoreline nursery sites used by cow-calf pairs and compared to shoreline sites that were not used by caribou within each park. Important characteristics were used to develop and evaluate Resource Selection Functions (RSFs) for calving woodland caribou in northern Ontario. Habitat characteristics determined at nursery sites were postulated to reflect predator avoidance strategies. Observed differences in habitat variables selected by female caribou in the 2 study areas primarily reflected broad ecoregional differences in vegetation and topography rather than differences in female choice. In Wabakimi Provincial Park, higher understorey tree density and lower ground detection distance played key roles in distinguishing nursery sites from sites that were not used. In Woodland Caribou Provincial Park, groundcover vegetation and shrub density were important in the selection of nursery sites by female caribou. Generally, female caribou in both parks selected nursery sites with greater slope, lower shrub density, but thicker groundcover vegetation, and higher overstorey cover than shoreline sites that were not used. The last objective was to determine what physical characteristics caribou might be using at a larger scale (i.e., distance to nearest land feature from nursery sites, distance to closest fly-in outpost from nursery sites). In Woodland Caribou Provincial Park more nursery sites occurred in the coniferous forest landcover type when compared to unused or random sites. In Wabakimi Provincial Park, there was no difference between nursery activity and landcover types randomly available in the study area. Generally, female caribou in both parks selected nursery sites with shorter escape distances than provided by unused or random sites, and islands were the feature type most frequently used for nursery activity. Female caribou also used clusters of land features within shorter distance of one another as compared to random points along the shoreline. Caribou cowcalf pairs typically used areas for nursery activity that were 9.0km (± 6.5km, range 2.3-20.6km) in Wabakimi Provincial Park and 10.0km (± 6.9km, range 0.7 - 32.6km) in Woodland Caribou Provincial Park from any human recreational disturbance. The identification of these important characteristics of caribou nursery areas at 2 different spatial scales provides baseline information that may be used to predict the locations of potential caribou nursery sites both within protected area boundaries and across the broader range of this valued species in northern Ontario. It is suggested that a first iteration spatial model be developed from the outcomes of this study to enable validation and refinement and to enhance the management and understanding of this critical life history requisite.