Author: Chad W. LeBeau

Publisher:

Published: 2012

Total Pages: 120

ISBN-13: 9781267621269

The demand for clean renewable energies and tax incentives has prompted a nationwide increase in wind energy development. Renewable energy development is occurring in a wide variety of habitats potentially impacting many species including greater sage-grouse (Centrocercus urophasianus). Greater sage-grouse require contiguous intact sagebrush (Artemisia spp.) habitats. The addition of wind energy infrastructure to these landscapes may negatively impact population viability. Greater sage-grouse are experiencing range-wide population declines and are currently listed as a candidate species under the Endangered Species Act of 1973. The purpose of my study was to investigate the response of greater sage-grouse to wind energy development. Mine is the first study to document the short-term effects of wind energy infrastructure on greater sage-grouse habitat selection, nest, brood, and female survival, and male lek attendance. I hypothesized that greater sage-grouse would select for habitats farther from wind energy infrastructure, particularly wind turbines, during the nesting, brood-rearing, and summer periods. In addition, I hypothesized that greater sage-grouse nest, brood, and female survival would decline in habitats with close proximity to wind turbines. Lastly, I hypothesized that greater sage-grouse male lek attendance would experience greater declines from pre wind energy development to 4 years post development at leks with close proximity to wind turbines compared to leks farther from turbines. My study area was located in south-central Wyoming between the towns of Medicine Bow and Hanna and consisted of one study area influenced by wind energy development (Seven Mile Hill) and a second study area that was not impacted by wind energy development (Simpson Ridge). I identified 14 leks within both study areas and conducted lek counts at each of these leks from 2008 to 2012. I captured 116 female greater sage-grouse from both study areas from 2009 to 2010. I equipped each female grouse with a VHF necklace-mounted transmitter and monitored them via telemetry during the nesting, brood-rearing, and summer periods within both study areas from 2009 to 2010. I documented greater sage-grouse habitat selection as well as nest and brood-rearing success and female survival. I used binary logistic regression in a use versus availability study design to estimate the odds of habitat selection within both study areas during the nesting, brood-rearing, and summer periods. I used Cox proportional hazards and Andersen-Gill survival models to estimate nest, brood, and female survival relative to wind energy infrastructure. Lastly, I used ratio of means tests and linear mixed effects models to estimate the degree of decline in male lek attendance at leks influenced by wind energy development versus leks with no influence 1 year prior to development to 4 years post development. Greater sage-grouse did not avoid wind turbines during the nesting and brood-rearing periods, but did select for habitats closer to turbines during the summer season. Greater sage-grouse nest and brood survival decreased in habitats in close proximity to wind turbines, whereas female survival appeared not to be affected by wind turbines. Peak male lek attendance within both study areas experienced significant declines from 1 year pre development to 4 years post development; however, this decline was not attributed to the presence of the wind energy facility. The results from my study are the first examining the short-term impacts to greater sage-grouse populations from wind energy development. Greater sage-grouse were not avoiding the wind energy development two years following construction and operation of the wind energy facility. This is likely related to high site fidelity inherent in sage-grouse. In addition, more suitable habitat may exist closer to turbines at Seven Mile Hill, which may also be driving selection. Fitness parameters including nest and brood survival were reduced in habitats of close proximity to wind turbines and may be the result of increased predation and edge effects associated with the wind energy facility. Lastly, wind energy infrastructure appears not to be affecting male lek attendance 4 years post development; however, time lags are characteristic in greater sage-grouse populations, which may result in impacts not being quantified until 2-10 years following development. Future wind energy developments should identify greater sage-grouse nest and brood-rearing habitats prior to project development to account for the decreased survival in habitats of close proximity to wind turbines. More than 2 years of occurrence data and more than 4 years of male lek attendance data may be necessary to account for the strong site fidelity and time lags present in greater sage-grouse populations.