The effects of electric power lines on the breeding ecology of greater sage-grouse

Abstract

Anthropogenic infrastructure can negatively affect wildlife through direct mortality and/or displacement behaviors. Some tetranoids (grouse spp.) species are particularly vulnerable to tall anthropogenic structures because they evolved in ecosystems void of vertical structures. In western North America, electric power transmission and distribution lines (power lines) occur in sagebrush (Artemisia spp.) landscapes within the range of the greater sage-grouse (Centrocercus urophasianus; sage-grouse). The U.S. Fish and Wildlife Service recommended using buffer zones near leks to mitigate the potential impacts of power lines on sage-grouse. However, recommended buffer distances are inconsistent across state and federal agencies because data are lacking. To address this, we evaluated the effects of power lines on sage-grouse breeding ecology within Utah, portions of southeastern Idaho, and southwestern Wyoming from 1998–2013. Overall, power lines negatively affected lek trends up to a distance of 2.7 and 2.8 km, respectively. Power lines died not affect lek persistence. Female sage-grouse avoided transmission lines during the nesting and brooding seasons at distances up to 1.1 and 0.8 km, respectively. Nest and brood success were negatively affected by transmission lines up to distances of 2.6 and 1.1 km, respectively. Distribution lines did not appear to affect sage-grouse habitat selection or reproductive fitness. Our analyses demonstrated the value of sagebrush cover in mitigating potential power line impacts. Managers can minimize the effects of new transmission power lines by placing them in existing anthropogenic corridors and/or incorporating buffers at least 2.8 km from active leks. Given the uncertainty we observed in our analyses regarding sage-grouse response to distribution lines coupled with their role in providing electric power service directly to individual consumers, we recommend that buffers for these power lines be considered on a case-by-case basis. Micrositing to avoid important habitats and habitat reclamation may reduce the potential impacts of new power line construction.

Greater sage‐grouse habitat function relative to 230‐kV transmission lines

“…In Utah, USA, female sage‐grouse with broods selected areas closer to transmission lines, but the authors acknowledged some potential confounding factors associated with this analysis (Westover et al ). At the landscape scale, transmission lines did not affect lek persistence in a multi‐state study (Kohl et al ). There are several unique characteristics associated with each of these studies, including location, duration, seasonal timing, size of power line, and habitat characteristics, all of which have the ability to influence the interpretation of the generalized effects of transmission lines on sage‐grouse populations.…”

“…In addition, a lack of newly established power lines limits our ability to implement well‐designed studies to address potential indirect effects with pre‐development data. Based on the few studies that exist, however, the extent and magnitude of effects appear to vary based on power line characteristics, amount of available habitat, and the affected population parameter (Armentrout and Hall , Schroeder , Westover et al , Gibson et al , Kohl et al ).…”

“…The variability among studies and power lines (e.g., voltage, size, configuration) makes it difficult to understand the potential effects of power lines on sage‐grouse populations. This variability could be due to study design, study location, and other factors, such as landscape configuration and habitat characteristics that potentially confound inference (Walters et al , Westover et al , Kohl et al ). For example, power lines are a linear feature often co‐located with other linear anthropogenic features, such as roads, making it difficult to disentangle which feature is potentially affecting a sage‐grouse population.…”

“…For example, power lines are a linear feature often co‐located with other linear anthropogenic features, such as roads, making it difficult to disentangle which feature is potentially affecting a sage‐grouse population. In addition, interactive relationships between biotic, abiotic, and anthropogenic factors suggests that pulses in sage‐grouse population growth, such as high recruitment in response to increased precipitation, may be mediated by habitats available to a population (Blomberg et al , Kohl et al ). The extent and magnitude of these interactive effects may be difficult to assess because of potential confounding issues and inherent characteristics of the affected sage‐grouse population.…”

“…In Nevada, USA, sage‐grouse resource selection and demography were negatively associated with habitats ≤12.5 km from a 345‐kV transmission line (Gibson et al ). In addition, lek trends, nesting and brooding habitat selection, and nest and brood success were negatively correlated with power lines ≤2.8 km from power lines (Kohl et al ). Whereas some researchers have documented negative relationships, others have not observed a relationship between power lines and different sage‐grouse population parameters.…”