Date of Award:

Spring 2017

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Wildland Resources

Advisor/Chair:

Terry A. Messmer

Co-Advisor/Chair:

Thomas C. Edwards

Third Advisor:

Shane B. Roberts

Abstract

The Columbian sharp-tailed grouse (Tympanuchus phasianellus columbianus; CSTG) has experienced range-wide population declines, primarily as a result of habitat loss or degradation, and currently occupies <10% of its historic range. Expansion of wind energy developments across the remaining occupied CSTG range has been identified as a potential threat to the species. To assess the potential influence of wind energy development on CSTG breeding season ecology, I captured and radio-marked 135 female CSTG during 2014-2015 at leks located between 0.1-13.8 km from wind turbines in restored grassland habitats. I subsequently monitored 147 nests and 68 broods and used an information-theoretic model selection approach to assess the potential influence of wind energy distance and density variables, multi-scale habitat features, temporal factors, and precipitation on CSTG nest site selection, daily nest survival, brood success, and chick survival. The best nest site selection model suggested a positive functional response to the amount of restored grassland habitat with >30% forb cover at the nesting core use (60 ha) scale. Daily nest survival was positively associated with visual obstruction readings at the nest and the amount of restored grassland habitat containing >30% forb cover at the core use (60 ha) scale. Nest site selection and daily nest survival were not influenced by proximity to turbines or turbine density at the core use or breeding season home range (1385 ha) scales. Early (14-day) brood success was positively influenced by post-hatch precipitation and late (42-day) brood success was positively influenced by earlier hatch dates. Chick survival to 42 days post hatch was positively influenced by post-hatch precipitation and earlier hatch dates and negatively influenced by increasing densities of wind turbines at the breeding season home range scale. The probability of an individual chick surviving to 42 days decreased by 50% when there were ≥10 turbines within 2.1 km of the nest. In restored grassland habitats, such as Conservation Reserve Program fields, I recommend plantings and management practices that will result in diverse, bunchgrass-dominated nesting habitat with residual grass cover and >30% forb canopy cover during the nesting season. My results suggest that wind turbines occurring within 2.1 km of nesting habitats (i.e., 4.8 km of occupied leks) may negatively affect CSTG recruitment.

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Biology Commons

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