Document Type

Thesis

Date of Degree Completion

Fall 2023

Degree Name

Master of Science (MS)

Department

Biology

Committee Chair

Daniel Beck

Second Committee Member

Kristina Ernest

Third Committee Member

Jason Irwin

Abstract

Solar energy development in the Southwestern United States coincides with habitat for many sensitive and endemic species, including reptiles such as Mojave Fringe-toed Lizards and Mojave Desert Tortoises who are threatened by a warming and drying climate. While utility-scale solar energy reduces carbon emissions and should ultimately benefit climate-sensitive species, it locally destroys fragile desert habitat, displaces wildlife, and has been shown to incur local air and surface temperature changes. Mitigation-based translocation of wildlife species in the face of solar development yields mixed results, and the unprecedented pace of solar expansion in the desert highlights the need for alternative practices in managing sensitive species in affected areas. One such proposed alternative is the reintroduction of wildlife back into solar arrays post-construction. All wildlife but especially reptiles are dependent on the availability of suitable environmental temperatures alongside other habitat requirements to persist in their environment, but the effect of solar arrays on the thermal environment for wildlife is unclear.

This study addresses the potential for utility-scale solar arrays to affect the thermal ecology of desert reptiles and other wildlife living within and alongside their developments. From April-October 2022 I documented some effects of solar arrays on the local thermal environment in the Lower Colorado River Valley subregion of the Sonoran Desert where extensive solar energy development is taking place. Using temperature dataloggers and operative temperature models, the latter of which emulated body temperatures of non-thermoregulating lizards, I compared environmental and operative temperatures between two solar arrays and unaltered desert habitat. I also used visual survey and camera-trapping techniques to observe the vertebrate communities living within solar arrays and compared them to natural surrounding habitat. I found that vertebrate species richness was reduced and communities were less similar within and adjacent to utility-scale solar arrays when compared to natural habitat. Operative temperatures of lizards in the shade beneath solar panels were 2-3 °C warmer than the same models under a natural shade source, suggesting that the thermal ecology of reptiles may be changed within these facilities. These findings support previous research documenting the local warming effects of utility-scale solar arrays and underscore the need for further research on their habitat suitability for threatened species. This study provides preliminary information on the effects of solar arrays on operative temperatures of reptiles in order to guide future research and potentially inform management and mitigation strategies for sensitive species affected by solar energy development.

Download

Share

COinS