Late-winter Habitat Use by Boreal Woodland Caribou (Rangifer tarandus caribou) in Northwestern Saskatchewan

Author

Gilbert PROULX, Editor

Received 27 October 2012 – Accepted 11 December 2012

Abstract

In an effort to better assess the impact of future timber harvest on wildlife, and to develop pertinent recovery plans for endangered species in specific locations, habitat queries (searches to retrieve data from a vegetation database) may be used to identify polygons (homogenous areas for specific forest stand characteristics) used by a species. During the late winters of 2009, 2011 and 2012, I developed and tested queries to predict the distribution of Boreal Woodland Caribou (Rangifer tarandus caribou) habitat in Mistik Forest Management Agreement (FMA) area, in northwestern Saskatchewan. The objectives of this study were to 1) identify polygons with late-winter habitat potential according to forest stand composition and structural characteristics, 2) verify habitat use by Woodland Caribou, and 3) identify stands that should be protected in the future. In 2009, with a query based on generalities taken from Woodland Caribou habitat studies conducted in areas other than the Mistik FMA area, only 25% of track encounters (n = 8) occurred in polygons judged to be suitable for Woodland Caribou. After modifying the original query to include muskegs (treed bogs, treed fens, and treed swamps) that were ≤2 km apart, and upland stands that were ≤2 km from these muskegs, 76% and 93% of track encounters occurred in suitable polygons in 2011 (n = 46) and 2012 (n = 45), respectively. As predicted, the majority (61.5%) of 91 track encounters (≤2 Woodland Caribou/track encounter in most cases) occurred in muskegs, and nearly 25% were in late-successional, upland deciduous and mixed coniferous-deciduous stands located within 2 km from the edge of muskegs. Track encounters were significantly more frequent than expected in muskegs (P<0.02), and less frequent than expected in unsuitable polygons (P<0.01). They were significantly (P<0.05) more frequent in Tamarack (Larix laricinia) stands with 21-40% canopy closure and 0-20 m-high trees, and in Tamarack stands with >40% canopy closure with 0-10 m-high trees. There were no track encounters in Black Spruce (Picea mariana) stands with 0-40% canopy closure and 0-20 m-high trees, and in Jack Pine (Pinus banksiana) pure or mixed coniferous stands. Track encounters were significantly less frequent than expected (P<0.01) in deciduous stands. In muskeg habitats used by Woodland Caribou, there was 1 track encounter/246 m of transect in 2011, and 1 track encounter/264 m of transect in 2012. Woodland Caribou track encounters were recorded at the beginning of transects, beside active roads and on pipelines, or further away depending on the distance of transects from roads and suitable muskeg habitat. The findings of this study led to a more effective rating of forest stands to predict the late-winter distribution of Boreal Woodland Caribou in Mistik FMA area. The index of track encounters/km of suitable muskeg habitat may be useful to assess the persistence of the Woodland Caribou population over time.

Key Words: Black Spruce, Boreal Woodland Caribou, Rangifer tarandus caribou, late-winter habitat, Saskatchewan, snowtracking, Tamarack

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