Date of Award:
Master of Science (MS)
Eric M. Gese
Cougars (Puma concolor) are difficult to census due to their large home ranges, low densities, and cryptic nature. The conventional “gold-standard” method for estimating cougar abundance entails the capture and radio-tagging of individuals in a study area in an attempt to acquire a direct enumeration of animals in the population. While this method provides an accurate abundance estimate, it is logistically challenging and prohibitively expensive. Noninvasive survey techniques may offer the ability to both accurately and inexpensively monitor cougar populations. While noninvasive techniques have been used on cougar populations, there remain questions on their accuracy and comparative efficacy. We estimated the density of a cougar population in Northwest Wyoming using direct enumeration, and used this estimate as a reference with which to evaluate the accuracy and cost-effectiveness of three types of noninvasive surveys performed between 2010 and 2014. The noninvasive methods included two annual mark- recapture sessions of: 1) remote camera trapping, 2) winter hair-collection transects, and 3) scat detection dog surveys.
We GPS tracked 13 adult cougars (males = 5, females = 8) over 3 annual periods (Sep 2010 – Sep 2013). We used proportional home range overlap to determine density in a 1,570 km2 area. The average density was 0.82 cougars/100 km2 (± 0.10 SD; n = 3 years). The remote camera surveys produced a mean density of 0.60 cougars/100 km2 (n = 2 years; relative SD = 56.5%). The scat detection dog surveys produced an average density of 2.41 cougars/100 km2 (n = 2 years; relative SD = 12.6%). The winter transects failed to produce a sample size large enough for an abundance estimate. Due to the inclusion of non-adults in the scat sampling, and the fact that the reference estimate was essentially a minimum count of adults, we believe that the scat-based estimate was more accurate than the lower estimate produced by remote cameras. Additional analysis indicated that individual identification of cougars in photographs may not be reliable, challenging the validity of photo-based abundance estimates of cougars. On a cost-per-detection basis, scat detection dogs were the most cost effective method (scat detection dogs = $341; remote cameras = $3,241; winter transects = $7,627).
Alexander, Peter D., "Comparing Conventional and Noninvasive Monitoring Techniques for Assessing Cougar Population Size in the Southern Greater Yellowstone Ecosystem" (2016). All Graduate Theses and Dissertations. 4712.
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