Large Scale Industry Collaboration to Evaluate the Status of Grizzly Bear Populations in the Slave Geological Province.Thursday, November 22, 2018 - 12:20 to 12:39 Theatre 3
The Ekati Diamond Mine and Diavik Diamond Mine are located in the Slave Geological Province (SGP) of the Northwest Territories, approximately 300 km northeast of Yellowknife. Potential impacts to grizzly bears in the SGP associated with mining activities were predicted to be minimal during the respective environmental assessments for these mines, but without detailed information about population status, testing this prediction is difficult. Regulators, monitoring agencies, and community members recommended that the mining industry collaborate on a large scale regional grizzly bear program to assess population status and monitor trends over time. In response, the Ekati and Diavik Diamond Mines agreed to work together on a large scale grizzly bear mark-recapture study surrounding their mine properties in the central barrens of the Northwest Territories. Technical and community workshops concluded that an important objective for grizzly bear monitoring was to determine the abundance and distribution of grizzly bears in a larger regional context and establish a baseline for long-term regional monitoring.
A DNA mark-recapture design was the best approach to meet this objective. The regional DNA study area is centred on the Ekati and Diavik Diamond Mines and contains 113 cells (12 km by 12 km) used for sampling grizzly bear hair in 2012, 2013, and 2017, for a total study area of approximately 16,000 km2. In 2012, 112 grizzly bear individuals were identified through DNA hair analysis, including 42 males and 70 females. During the 2013 field program, a total of 136 grizzly bears were identified (60 males and 76 females), including 39 that had no previous detections in the regional database (22 males and 17 females). In 2017, 136 grizzly bears were identified (55 males and 81 females), including 62 with no previous detections in the regional database (33 males and 29 females).
Based on Spatially Explicit Capture Recapture (SECR) analysis of the individuals detected, female density was estimated as 3.6/1,000 km2 (95% CI 2.9 to 4.6) in 2012 and 4/1,000 km2 (95% CI 3.2 to 5) in 2013. Male density was estimated as 2/1,000 km2 (95% CI 1.4 to 2.7) in 2012 and 2.9/1,000 km2 (95% CI 2.2 to 3.7) in 2013. The 2017 density of both males (3/1,000 km2) and females (4.7/1,000 km2) continued to show an increasing trend in comparison to the previous monitoring years. The results of this regional study indicate a stable to growing population in the central barrens of the Northwest Territories relative to estimates for the Slave Geological Province in the late 1990’s.