Date of Award
Master of Science (MS) in Biology
"In the Pacific Northwest, quaking aspen (Populus tremuloides) support large amounts of biodiversity and are considered second only to riparian zones. Due to aspen's ecological importance and recent decline on Turnbull National Wildlife Refuge (TNWR), increasing aspen regeneration is of high priority. The elk (Cervus elaphus) population on TNWR has greatly increased over the last decade and over browsing is attributed as a factor affecting aspen regeneration. In response to the decline of aspen regeneration, TNWR initiated an elk hunt in 2010 to cull and disperse elk. However, hunting is not a viable solution in public use areas of the refuge, and previous data have shown that elk may be moving into those areas. To determine if elk are found more frequently in non- hunt areas ofTNWR, radio-collared cow elk were tracked bi-weekly from July 2011 to March 2012. I found that the frequency of elk locations in non-hunt areas of the refuge was greater when compared to their frequencies in hunt areas and off refuge, before and during early-hunt. During the late-hunt, elk frequencies in the non-hunt and off refuge sites were significantly greater than hunt areas, and following the hunt elk frequencies on off refuge sites were significantly greater than hunt areas. Elk seem to be using non-hunt areas of the refuge more than other areas during the hunt, which may increase browsing pressure on aspen in those areas. I examined if cougar and/or wolf urine were effective at deterring elk browsing in non-hunt areas of the refuge where there may be higher browsing pressure. I established 24 6x6m aspen plots throughout non-hunt areas with 8 plots per treatment (control, wolf, and cougar), and with half of each plot area fenced to provide an internal control. Aspen were measured and placed into size and browse classes prior to the addition of deterrents in November 2011 and following treatments in July 2012. There were no measureable differences in size or browse class between fenced areas across treatments. Non-fenced areas were more browsed than associated fenced areas, however there were no measureable changes in size or browse class for non-fenced areas across treatments. While alternative measures need to be taken to help decrease aspen browse, it is not clear if wolf or cougar urine effectively deter browsing"--Document.
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Walker, Savanah, "Effects of predator urine on deterring ungulate browsing of aspen on the Turnbull National Wildlife Refuge" (2012). EWU Masters Thesis Collection. 65.