Yudi Li

and 4 more

Large, ground-mounted photovoltaic solar farms (GPVs) are expanding worldwide to support climate change mitigation and the transition towards a low-carbon economy. Few studies have explored the ecological impacts of tracking GPVs and maintenance activities for utility-scale operations on microclimate and vegetation patterns. Here, we explored the ecological impacts of a single-axis, tracking GPV and regular mowing in the Great Central Valley of California, United States. First, we developed an experimental framework of five unique “micro-patches” that characterize the heterogeneity of the dynamic microclimate and vegetation zones created by a single-axis, tracking GPV. Across these five micro-patch types, we evaluated nine above- and below-ground microclimate variables and 16 vegetation properties. We found that the micro-patches under PV panels reduced photosynthetic active radiation and wind speed by 90% and 46%, respectively, compared to open spaces along the facility perimeter. In contrast, soil surfaces in the open spaces were warmer and experienced faster soil moisture loss than micro-patches near or within array footprints during drought seasons. We found no significant difference in air temperature, relative humidity, and vapor pressure deficit across all micro-patches daily. We identified 37 plant species, of which 86% were exotic. Fully exposed to higher incoming solar radiation, plant communities in the open spaces experienced senescence the earliest compared to other micro-patches. We discuss the implications of our results for managing single-axis, tracking GPVs, particularly activities seeking to achieve enhanced control of the noxious weeds and other ecologically beneficial outcomes.