Date of Award:
Doctor of Philosophy (PhD)
Terry A. Messmer
Terry A. Messmer
Mark W. Brunson
Dave K. Dahlgren
Douglas R. Ramsey
Eric T. Thacker
Sagebrush (Artemisia spp.) ecosystems are diverse habitats found throughout western North America. Anthropogenic disturbances has resulted in the loss of over half of the sagebrush ecosystems impacting sagebrush obligate species such as sage-grouse (Centrocercus spp.). Federal, state, and private land managers have implemented landscape scale mechanical pinyon (Pinus spp.) and juniper (Juniperus spp.; conifer) removal projects in an effort to restore functioning sagebrush communities to benefit sage-grouse. However, few studies have investigated the potential for using large-scale conifer treatments to mitigate factors impeding sage-grouse seasonal movements and space-use in anthropogenic altered landscapes.
To address this management need, I analyzed pre- and post-treatment vegetation composition data and annual changes in percent cover for known conifer treatments completed from 2008-2014 in Box Elder County, Utah, USA. I developed a multivariate generalized linear regression model that predicts future landscape conditions for sage-grouse and projects tree canopy cover that approximated observed cover values for known treated plots at time of treatment and five years post-treatment.
Next, I analyzed five different management scenarios to predict resource selection by greater sage-grouse (Centrocercus urophasianus) in response to changes in habitat following conifer treatments. I used a Relative Selection Strength (RSS) framework to quantify the net habitat gain from 2017 to 2023. My top ranked treatment scenario showed net habitat gains across all categories.
Additionally, I investigated the efficacy of global position system (GPS) and very high frequency (VHF) transmitters used in range wide studies. I compared mortality rates for two separate Utah populations. Across summer and winter for sex, and spring, summer and winter for age, I documented higher mortality for sage-grouse marked with GPS transmitters.
Lastly, to assess stakeholders’ perceptions of contemporary community-based conservation efforts, I conducted a case study in fall 2019 of the West Box Elder Coordinated Resource Management (CRM). Respondents reported: participation by federal and state agencies was paramount for funding and program structure, trust has been enhance, and landowner involvement is necessary for long-term stability and persistence.
Small, Justin R., "Greater Sage-Grouse and Community Responses to Strategies to Mitigate Environmental Resistance in an Anthropogenic Altered Sagebrush Landscape" (2021). All Graduate Theses and Dissertations. 8042.
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