Power pole density informs spatial prioritization for mitigating avian electrocution

Abstract

Raptor and corvid electrocutions cause continental conservation concerns for breeding, migrating, and wintering birds. Although concerns are widespread, mitigation is implemented primarily at local scales of individual electric utilities. By not considering landscape-scale patterns, conservation strategies may fail to focus mitigation where efforts are needed most. To enable resource managers to consider electrocution risk at larger scales, we developed a regional model of distribution power pole (pole) density in a grid of 1-km 2 cells throughout Colorado and Wyoming. To do so, we obtained data on pole locations from a sample of electric utilities covering 31% of Colorado and Wyoming, and developed a predictive model of poles throughout the remainder of the 2 states. Pole density was influenced by road lengths, number of oil and gas wells, slope, development, and land cover. Poles were densest in areas with high road lengths, high numbers of wells, and relatively flat terrain, and in areas developed for agriculture or human residences. When model predictions are viewed together with species-specific habitat maps, locations where high pole densities overlap habitat suggest areas where mitigating electrocution risk could be prioritized. Communication between resource managers and local utilities could then clarify the poles that caused the highest risk to raptors from electrocution. Thus, the model provides a framework for systematic spatial prioritization in support of regional conservation planning to minimize electrocution of raptors and corvids. Ó 2016 The Wildlife Society.

Using risk prediction models and species sensitivity maps for large-scale identification of infrastructure-related wildlife protection areas: The case of bird electrocution

“…Otherwise, bird electrocution ocurrence also increased near roads, consistent with previous studies (Guil et al, 2011;Dwyer et al, 2014). A high abundance of prey near roadsides, as well as the common co-occurrence of roads and power lines (Dwyer et al, 2016), could explain this relationship, although a search bias in the exploration of these areas cannot be ruled out.…”

“…Similar results have been found in studies at the pylon scale (Mañosa, 2001;Janss and Ferrer, 2001;Tintó et al, 2010;Guil et al, 2011) and the regional scale (Dwyer et al, 2016). The relationship between landscape composition and electrocution mortality is heavily influenced by the species involved.…”

“…Because power line distribution might significantly influence our risk model (Dwyer et al, 2014(Dwyer et al, , 2016, we conducted a deviance partioning analysis (Bocard et al, 1992) to disentangle the relative weight of power line distribution with respect to the other landscape variables and the spatial autocorrelation intrinsic to our data. We calculated the deviance explained using a multivariate model, including all variables together and then pairwise.…”

“…Moreover, electrocution risk is determined not only by hazards associated with individual pylons; the exposure to sensitive birds is also important. Thus, the likelihood of electrocution risk is higher when dangerous pylons are located in areas where electrocution-sensitive birds are present (Fernández-García, 1998;Mañosa, 2001;Tintó et al, 2010;Guil et al, 2011;Dwyer et al, 2014Dwyer et al, , 2016.…”

“…To address the challenges outlined above, Dwyer et al (2016) proposed the use of a regional prediction model using power pole density as a surrogate of bird electrocution, combined with a foraging map of a sensitive species, to locate priority areas for mitigating avian electrocution. Although this proposed procedure is promising for identifying priority areas, some limitations include the assumption of homogeneity in power pole design and the linear relationship between power pole density and avian electrocution mortality.…”