Effects of solar energy development on ants in the Mojave Desert

Authors: GRODSKY, STEVEN - Us Geological Survey (USGS); Roeder, Karl; Campbell, Joshua

Submitted to: Ecosphere
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/21/2023
Publication Date: 10/23/2023
Citation: Grodsky, S., Roeder, K.A., Campbell, J.W. 2023. Effects of solar energy development on ants in the Mojave Desert. Ecosphere. 14(10). Article e4668. https://doi.org/10.1002/ecs2.4668.
DOI: https://doi.org/10.1002/ecs2.4668

Interpretive Summary: Deserts are high priority environments for solar energy development, but knowledge on how land-use change affects desert ecosystems and the soils, plants, and animals that live there is lacking. Thus, our objective in this study was to disentangle the response of one group of beneficial insects—the ants—to various types of management decisions at the Ivanpah Solar Electric Generating System in the Mojave Desert, USA. We focus on ants as they are abundant, ecologically important, and often act as bioindicators of ecosystem health. We used pitfall traps to collect ants in treatments representing different solar energy development decisions, including variably intense site preparation practices that include blading, mowing, and the establishment of undeveloped patches. We determined that blading (e.g. bulldozing) significantly reduced the abundance and diversity of ants compared to all other treatments. However, less intensive practices like mowing and undeveloped patches were similar to control plots outside the solar facility. Our results further suggest that ants may serve as useful bioindicators of solar energy infrastructure as some species with high ecological value (e.g., harvester ants) decreased with management intensity. Negative effects of solar energy development on ants can have significant implications for desert ecosystem function and integrity, but conservation-minded solar facility design and construction may reduce undesirable results during the renewable energy transition.

Technical Abstract: Deserts are highly prioritized recipient environments for ground-mounted solar energy development globally. Land-use change from solar energy development may affect desert ecosystems and the soils, plants, and animals therein, yet our understanding of these interactions is nascent. With their ubiquity, criticality as ecosystem constituents, and sensitivity to environmental variation, ants may be useful study organisms for elucidating ecological effects of solar energy development in deserts. Our objectives were to disentangle the response of a desert ant community to solar energy development decisions and test the efficacy of ants as bioindicators at Ivanpah Solar Electric Generating System (ISEGS, 392 MW) in the Mojave Desert, USA. We used pitfall traps to collect ants in treatments representing different solar energy development decisions, including variably intense site preparation practices: blading (i.e., bulldozing) and mowing, and establishment of undeveloped patches in solar fields replicated across three power blocks comprising ISEGS and in undeveloped control sites surrounding ISEGS. We determined that ant abundance, species richness, Shannon Diversity Index, and functional richness was lower in bladed treatments than in all other treatments and controls. For most taxonomic and functional ant responses, we detected no difference between non-bladed treatments and controls; these results suggest that less intensive site preparation and increased spatial heterogeneity (i.e., undeveloped patches in solar fields) reduce negative effects of solar energy development on desert ants. However, our results suggest that ants may serve as useful bioindicators of the severity of anthropogenic disturbance from solar energy development in deserts, and indicator analysis signifies that solar energy infrastructure may negatively affect some species with high ecological value (e.g., harvester ants). Negative effects of solar energy development on ants can have significant implications for desert ecosystem function and integrity, but conservation-minded solar facility design and construction may lead to avoidance of “bottom-up” ecological ramifications of increased solar production during the renewable energy transition.