Ecological Impacts of Single-Axis Photovoltaic Solar Energy with
Periodic Mowing on Microclimate and Vegetation
Abstract
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.