Reducing effort while improving inference: Estimating Dall's sheep abundance and composition in small areas

A Bayesian analytical approach significantly reduces the sample size requirements for estimating Dall's sheep (Ovis dalli) abundance while improving precision, making it feasible to conduct distance sampling surveys in small or low-density areas. The study estimated populations of 2,252, 2,809, 1,669, and 12,428 sheep across Denali National Park and Preserve (DENA), Western Arctic National Parklands (WEAR), Itkillik preserve subarea, and Wrangell-St. Elias National Park and Preserve (WRST), respectively, using only 57 to 100 group detections—50–75% fewer than previously recommended. This was achieved by borrowing detection information across surveys and incorporating informed priors, demonstrating the method's efficiency in small-area conservation assessments.

Schmidt, J. H., & Rattenbury, K. L. (2013). Reducing effort while improving inference: Estimating Dall’s sheep abundance and composition in small areas. The Journal of Wildlife Management, 77(5), 1048–1058. Portico. https://doi.org/10.1002/jwmg.557