Date of Award:

5-2017

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Wildland Resources

Committee Chair(s)

Terry A. Messmer

Committee

Terry A. Messmer

Committee

Thomas C. Edwards

Committee

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 of CSTG breeding season ecology, I captured and radio-marked 135 female CSTG drugin 2014-2015 at leks located between 0.1-13.8 km from wind turbines in restored grassland habitats. Using radio-telemetry, I monitored 147 nests and 68 broods and developed models to assess the influence of wind turbines, roads, habitat features temporal factors, and precipitation on CSTG nest site selection, nest survival, brood success, and chick survival. Female CSTG in my study selected nest sites in grassland habitats where >30% of the canopy cover in the nesting core use area was composed of forbs (i.e., broadleaf plants). The strength of selection for this habitat type increased as its availability increased on the landscape. Nest survival increased with higher visual obstruction readings (i.e., concealment) at the nest bowl and in grassland habitats where forb cover exceeded 30% in the nesting core use area. I did not detect an influence of wind turbines or roads on nest site selection or nest survival. Early brood success (i.e., ≥1 chick alive at 14 days post-hatch) was higher when precipitation readings were higher in the first 7 days after hatch. Late brood success (i.e., ≥1 chick alive at 42 days post-hatch) was higher for nests that hatched earlier in the season. Survival of individual chicks to 42 days post-hatch was positively influenced by post-hatch precipitation (days 0-7) and early hatch dates, but was negatively influenced by increasing turbine densities 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 (e.g., farm bill program fields and state wildlife management areas), 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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