An Evaluation of Potential Pronghorn (Antilocapra americana) Responses to Wind Energy Development in North-Central Arizona

Pronghorn (Antilocapra americana) are one of the most susceptible ungulate species to anthropogenic disturbances including various forms of energy extraction. Today pronghorn face a new, ever increasing presence on the... [ view full abstract ]

Pronghorn (Antilocapra americana) are one of the most susceptible ungulate species to anthropogenic disturbances including various forms of energy extraction. Today pronghorn face a new, ever increasing presence on the landscape – wind energy facilities. Approximately 36% of all U.S. wind energy production occurs within the core distribution of pronghorn yet there is little published or unpublished research as to how wind turbines may impact pronghorn. We designed a study that measured pronghorn movement patterns using Browning Bridge Movement Models to calculate utilization distributions of free-ranging pronghorn in and around a wind facility. This study addressed three primary objectives in order to identify whether or not pronghorn displayed any avoidance to the wind facility or its turbines. These objectives were to: 1) identify movement patterns within and near an operational wind facility in north-central Arizona; 2) evaluate any measurable impacts the wind facility may have on pronghorn movement patterns; and 3) collect pre-construction movement data for future planned wind energy development in the area. In 2010-2011, we captured 17 female and 7 male pronghorn and fitted them with GPS-collars. These collars collected location data from the 24 individuals for 18-months (between 2010 and 2013). We used the location data to calculate core (50%) and primary (95%) utilization distributions and travel distances for each pronghorn. Of those pronghorn crossing between turbines (~5% of all movements) there was no significant relationship between exterior and interior turbines (p = 0.275). Male pronghorn crossed further (more towards the center between turbines; 140 [SE ± 13.2] m vs. 80 [SE ± 2.5] m, respectively) and less frequently (23.8 vs. 64.6 crossings/individual, respectively) between turbines than did females in all cases of turbine operation (moving and non-moving turbine blades). Finally, pronghorn tended to utilize the areas within the wind facility more often in the winter months (November through February) than the summer months (April through October). Overall, we did not find any evidence that suggested pronghorn were avoiding the wind facility. However, we did identify that male pronghorn tended to cross more towards the center between turbines maximizing distance from the turbines. Additionally male crossed between turbines less frequently than did females although they both utilized habitat immediately adjacent to the turbines. These results suggest that pronghorn populations may not avoid otherwise suitable habitat in the presence of an operational wind facility, however, there may be management practices available that could improve connectivity and permeability for males with specific attention to turbine micro-siting (e.g., small increases in inter-turbine distances). Furthermore, by maintaining and enhancing pronghorn habitat in and around wind facilities during and post-construction, pronghorn should continue to utilize the landscape without experiencing negative impacts with the operation of the turbines.