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Brown Bear Density, Denali National Park, Alaska, and Sighting Efficiency Adjustment

Brown Bear Density, Denali National Park, Alaska, and Sighting Efficiency Adjustment

Aerial surveys conducted in 1983 over a stratified random sample from about 2,500 km2 in the northeastern part of Denali National Park were used to estimate the brown bear (Ursus arctos) population. Twenty-three flights, totaling 68 hours, were made in a low-flying, fixed-wing aircraft; the sample coverage totaled 4,590 km2. Aerial counts were calibrated against simultaneous, multi-observer ground coverage. A new technique combining digitized topographic and vegetation information was used to adjust for sighting efficiency. Calibration results and plot characteristics were combined to estimate sighting efficiency on all plots. The minimum density estimates for the study area, based on animals seen, were 1/44, 1/70, and 1/476 km2 for individual bears, bear units, and families, respectively. The same values expanded by estimated sighting efficiency were 1/31, 1/49, and 1/163.

  • Author(s) Frederick C. Dean
  • Volume 7
  • Issue
  • Pages 37-43
  • Publication Date 1 January 1987
  • DOI 10.2307/3872605
  • File Size 897.71 KB
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