Trade-offs between utility-scale solar development and ungulates on western rangelands

ABSTRACT

Utility-scale solar energy (USSE) has become an efficient and cost-effective form of renewable energy, with an expanding footprint into rangelands that provide important habitat for many wild ungulate populations. Using global positioning system data collected before and after construction, we documented the potential impacts of USSE on pronghorn (Antilocapra americana), including direct habitat loss, indirect habitat loss, and barrier effects to both resident and migratory population segments. Our case study highlights the challenges that USSE poses to ungulate conservation, including (1) impermeable security fencing that blocks access to and reduces connectivity between formerly available habitats, and (2) the lack of guidelines for minimizing USSE impacts on ungulates. Improved siting and ungulate-specific best management practices would help to minimize habitat loss and retain landscape connectivity. Ungulate biodiversity and ecosystem services (for example, services provided by long-distance migratory species) in arid rangelands are important considerations when balancing the global benefits of renewable energy with local wildlife impacts.

Excerpt of Introduction

Yet the impacts associated with utility-scale solar energy (USSE; ≥1 megawatt [MW]) are evident in the amount of land these installations require, and can be exacerbated in arid landscapes where plant and wildlife communities are especially sensitive to disturbance (Grodsky and Hernandez 2020). With the exception of several avian (Kosciuch et al. 2020) and sensitive (Agha et al. 2020) species, the potential impacts of solar  development on wildlife, and specifically ungulates, are largely undocumented (Lovich and Ennen 2013). As USSE installations expand in size and distribution, understanding the potential effects on ungulates is needed to inform siting and layout design, and to weigh the broader trade-offs of mitigating climate change against impacts on local wildlife and ecosystem services. 

Pronghorn (Antilocapra americana) occupy the open plains and arid rangelands of the Intermountain West, an area heavily impacted by fossil-fuel extraction in recent decades (Jones et al. 2015). Such habitats are now also hotspots for USSE because of their excellent solar energy potential (Lovich and Ennen 2011) and proximity to states with renewable energy portfolio standards (Barbose 2019). Pronghorn appear especially vulnerable to USSE impacts because they prefer flat, open habitats ideal for solar development. Furthermore, as a wide-ranging species, pronghorn are more susceptible to linear barriers (such as roads and fences) and fragmentation effects than other ungulates (Jones et al. 2019; Xu et al. 2021).

Unlike other forms of energy development (eg wind or natural gas) that remain permeable to ungulates (Sawyer et al. 2013), safety regulations require USSE perimeters be surrounded by 2-m-tall, chain-link fencing (NFPA 2017), making habitat within solar projects inaccessible to pronghorn and other ungulates. In addition to habitat loss, USSE may also alter or block ungulate movements or migrations, depending on site location, size, and layout design. Given the rapid expansion of USSE, it is critical to understand the consequences of habitat loss and identify ways to make USSE more permeable to wide-ranging ungulates to inform stakeholder decisions regarding project siting and design.