•  
  •  
 

Abstract

The construction and operation of electric power transmission lines (“power lines”) and their associated infrastructure has been identified as a conservation threat to the greater sage-grouse (Centrocercus urophasianus; sage-grouse). The conservation buff er zones recommended by state and federal agencies to avoid potential impacts on breeding populations diff er because information regarding the effects of power lines on sage-grouse is lacking. Little information is available regarding sage-grouse responses to power lines placed in winter habitat. Hence, we evaluated sage-grouse habitat use before and after construction of the Sigurd-Red Butte (SRB) 345-kilovolt (kV) transmission line in winter habitat. The SRB line was constructed in the fall of 2014, and was sited parallel to a pre-existing 500-kV transmission line through salt-desert habitat on the western edge of what is now the Bald Hills Sage-Grouse Management Area (SGMA) in southern Utah. We deployed Global Positioning System (GPS) transmitters on 2 female and 16 male sage-grouse from 2014–2016 and compared collected locations to data independently acquired in the winter of 2011–2012 to determine if the construction of the SRB transmission line altered sage-grouse winter habitat use. Using the 2014–2016 data, we developed a resource selection function (RSF) model to quantify the influence of transmission line presence on sage-grouse movements while accounting for low quality habitat (salt-desert) near the transmission line. Post-construction data were compared to the 2011–2012 data to evaluate whether RSF-predicted changes in relative probability of use were reflected in actual shifts in habitat use before and after construction. The top RSF model contained a significant negative interaction between distance to transmission line and average salt-desert coverage within a 1-km2 moving window. Although a comparison of pre and post-construction mapped RSFs predicted a decreased probability of winter habitat use in the vicinity of the transmission line corridor as a result of the new line, we did not detect increased avoidance by sage-grouse when comparing spatial distributions between winters using minimum convex polygons. This suggests that immediate negative effects of new transmission line construction can be eliminated by implementing best management practices such as co-locating the transmission line in a preexisting energy corridor where impacts on habitat selection have already occurred, and siting the line in poor-quality habitat that does not fragment existing habitat. However, we caution that there may be other long-term influences of transmission line installation that are outside the scope of our 2-year post-construction study design, and more research is required to assess the influence of transmission lines on sagegrouse winter habitat use over longer timescales.

Download

Share

COinS