Date of Award:
Master of Science (MS)
S. Nicki Frey
S. Nicki Frey
Pinyon juniper woodland expansion into Greater sage-grouse (Centrocercus urophasianus, hereafter ‘sage-grouse’) habitat in southern Utah continues to threaten sage-grouse survival. Habitat restoration after pinyo-juniper removal treatment is key to the continued persistence and survival of sage-grouse along the southern edge of their range. Few long-term studies are available that examine sage-grouse use of areas treated to remove pinyon-juniper forests (i.e., ‘restored habitat’). The purpose of this research was to determine if sage-grouse used ‘restored’ areas in the long-term, as a measure of the actual effectiveness of pinyon-juniper woodland control treatments. I compared vegetation composition, shrub height and shrub cover at known sage-grouse locations to randomly selected sites within a pinyon-juniper removal treatment that was conducted in 2005 Sage-grouse use of pinyon juniper treatments was determined using locations recorded from GPS transmitters between September 2020 - December 2021. Additionally, to determine the change within the treatment area over the course of 15 years, I compared vegetation composition, shrub height, and shrub cover from data collected 2006-2009 to similar data collected in 2020-2021. I used this information to determine if habitat restoration was comparable to Utah sage-grouse state guidelines implemented in 2020. Using ANOVA to analyze these comparisons I found that the largest difference in variance between sage-grouse locations and the treated area was the percentage of forb cover, with sage-grouse locations containing more forb cover. I modeled seasonal home ranges during the breeding, summer, and fall/winter periods for all females. I calculated the percent of these home ranges found within the seasonal habitats of the Panguitch Sage-grouse Management Area. When analyzing sage-grouse home ranges within pinyon juniper removal treatments I found the highest percentage within pinyon juniper treatments 5 years old or less. Monitoring the southern edge of the sage-grouse range is particularly important as climate change is a major concern impacting sage-grouse habitat selection. Managers should conduct pinyon juniper removal treatment while maintaining and increasing forb cover to support sage-grouse. Information from this study will inform land managers in restoring sage-grouse habitat and help determine how to augment current management guidelines to better support sage-grouse habitat in southern Utah.
Donnelly, Benjamen, "Greater Sage-Grouse Response to Tree Canopy Removal: Habitat Vegetation Composition and Sage-Grouse Use 10–15 Years Post Treatment in the Southern Periphery of the Species Range" (2023). All Graduate Theses and Dissertations, Spring 1920 to Summer 2023. 8869.
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