Made in the shade : Leaf responses of native wildflowers to single‐axis photovoltaic solar energy

Li, Yudi and Magney, Troy and Armstrong, Alona and Hernandez, Rebecca R. (2025) Made in the shade : Leaf responses of native wildflowers to single‐axis photovoltaic solar energy. Plants, People, Planet. ISSN 2572-2611

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Abstract

Societal Impact Statement: As solar energy expands globally, balancing renewable power generation with biodiversity and ecosystem health has become an urgent challenge. This study investigated how native wildflowers respond at the leaf level to the unique microclimates created by rotating solar panels in California's Central Valley. We found that panels reduced light and water stress while prompting leaf area expansion, particularly in shade‐tolerant species. These insights reveal the potential benefits of partial shade in semi‐arid regions, highlight the plasticity of native wildflowers to altered microenvironments, and underscore the importance of strategic species selection to advance ecological restoration efforts at large solar farms. Summary: Ground‐mounted photovoltaic solar energy facilities (GPVs), especially those equipped with tracking systems, are rapidly expanding worldwide, raising growing concerns about land‐use conflict and environmental degradation. Co‐locating GPVs with ecological restoration is gaining popularity, representing a promising pathway towards sustainable renewable energy development. Yet, the physiological and morphological responses of incorporated plants to GPVs remain understudied, hindering strategic planning and the effectiveness of revegetation. A combination of rapid, minimally invasive methods was employed in both field and laboratory settings to investigate leaf acclimations over a 12‐month period in two native perennial wildflowers—differing in lifeform and shade tolerance—that were sown and successfully established after a full growing season at a single‐axis tracking GPV site in the semi‐arid Central Valley of California. Shadow cast by PV infrastructure alleviated excess light and water stresses, promoted leaf area expansion, and suppressed polyphenol accumulation in both species. Some responses fluctuated diurnally with panel rotation, while seasonal variations were primarily governed by ontogenetic development. Both perennials thrived within the array footprint, though Phacelia californica exhibited greater light‐use efficiency, transpiration rate, and chlorophyll content compared with the sun‐loving competitor Grindelia camporum , which showed notable plasticity but reduced stomatal conductance, indicative of a more conservative water‐use scheme. By revealing species‐specific, spatiotemporal patterns of leaf acclimation in two native wildflowers, this study highlights how fine‐scale microclimatic variability—driven by single‐axis tracking GPVs—modulates leaf physiological and morphological responses, thereby informing strategies to align renewable energy production with biodiversity net gain and ecosystem service delivery.