Stenhouse, G.B.( fRI Research, Grizzly Bear Program), Boulanger, J. (Integrated Ecological Research), Efford, M. (Dept. of Mathematics and Statistics, University of Otago), Rovang, S., McKay, T. Sorensen, A., and Graham, K. ( fRI Research, Grizzly Bear Program)
October 2015
Abstract
The first provincial grizzly bear DNA population inventory assessment was conducted in Bear Management Area 3 (BMA 3) within the Yellowhead population unit in 2004. Ten years after this first inventory, funding and support were provided by provincial and federal government agencies along with two forest management tenure holders to repeat and expand the second grizzly bear population inventory in 2014.
The area studied in 2014 included BMA 3, along with an expansion into the White Goat Wilderness Area to the south. In addition, for the first time, the southern portion of JNP (JNP) was inventoried. The study design for this project incorporated our current knowledge of the study areas, applied spatially explicit capture recapture (SECR) methods, and used DNA hair samples collected using non-invasive approaches.
The goals of this study were to:
Overall, 108 unique bears were detected within the 2014 sampling area, including 63 bears in BMA 3, 16 bears in the White Goat Wilderness Area, and 29 bears in south JNP. The SECR population estimate indicates that the population estimate for BMA 3 is 74.2 grizzly bears (CI = 56.2-98.0) while the south JNP population estimate is 54.0 grizzly bears (CI = 39.8-73.2). An additional 10.4 (Cl=7.6-14.2) bears are estimated in the White Goat and surrounding area. When viewed as a single ecosystem, the population estimate would be 138.6 grizzly bears, with a confidence interval of 114.6 to 167.7 animals.
These new population estimates indicate the population of bears in BMA 3 has increased since the previous population inventory work was completed in 2004. Estimates for the 2004 DNA sampling grid based on SECR analysis was 36 bears (CI 28.6-45.3) in 2004 compared to 71.3 bears (CI 53.9-94.2) in 2014. Our findings represent an annual population rate of increase of approximately 7%, which is higher than commonly seen in most interior grizzly bear populations in North America. The reasons for this observed rate of population increase are unclear and require additional investigation and analysis to determine whether current and past management actions are contributing to this rate of increase.
In 2008, a DNA-based population estimate was completed in the northern half of JNP. Combining the north JNP population estimate with current data results in an estimated total of 113 grizzly bears residing within the boundaries of JNP. However, this estimate is based on the assumption that grizzly bear densities in north Jasper have remained constant since 2008.
Results from this inventory indicate that spatially explicit methods obtain robust estimates with less sampling effort through the use of sampling stratification. These techniques can be employed in future population inventory work in other provincial BMAs to reduce overall project costs.