Date of Award:
Master of Science (MS)
S. Nicole Frey
The greater sage-grouse (Centrocercus urophasianus; sage-grouse) is a species of conservation concern that occupies sagebrush-dominated (Artemisia spp.) landscapes across the western United States and southern Canada. The U. S. Fish and Wildlife Service (USFWS) reviewed the status of the sage-grouse in September 2015 and determined that it did not warrant protection under the Endangered Species Act due to collaborative efforts between numerous public and private stakeholders. However, this decision hinged on federal and state commitments to continue science-based management of sagebrush habitats. As human development increases across the west, there is an increasing need for understanding the impacts of disturbance on sage-grouse. Filling this knowledge gap is important because it will allow us to predict how sage-grouse populations may respond to changes in the future. I assessed how two types of disturbance (wildfire and transmission line construction) influenced habitat use of a population of sage-grouse in southern Utah. I deployed Global Positioning System (GPS) transmitters on 26 (21 male and 5 female) sage-grouse in the Bald Hills Sage-Grouse Management Area in 2014 and 2015 to record what habitat sage-grouse were using during the summer and winter seasons. I compared these used locations to habitat that was seasonally available to the birds using resource selection functions. My models showed that in the summer, birds showed preference for areas burned and reclaimed within the last 10 years. I suggest that this may be occurring because the birds are seeking out vegetation that was seeded by the Bureau of Land Management (BLM) during wildfire reclamation. In the winter, my models showed an overall 3% decrease in predicted probability of use for winter habitat in the vicinity of the transmission line corridor, but this change did not immediately result in increased avoidance by sage-grouse when comparing spatial distributions for sage-grouse locations within winter habitat near the transmission line. I suggest that this is because the new transmission line was paired with a preexisting line which was already avoided by sage-grouse. However, the construction of the new line could have long-term consequences outside the two year scope of my study. These impacts could be delayed because sage-grouse are strongly tied to historic habitats and may not change habitat use immediately in spite of landscape changes. Additionally, the presence of the new line could cause indirect landscape changes which may only manifest over longer time periods such as increasing human activity in the area or changing the distribution of avian predators of sage-grouse that use the transmission line for perching. I recommend continued monitoring of sage-grouse in the area to determine if any changes in habitat use manifest in future years.
Hansen, Erica P., "Influence of Disturbance on Greater Sage-Grouse Habitat Selection in Southern Utah" (2016). All Graduate Theses and Dissertations. 5231.
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