Disentangling the drivers of solar farm biodiversity

Alongside renewable electricity generation, solar farms can be designed and managed to incorporate biodiversity benefits. Understanding of site management impacts are emerging and the abundance or diversity of some taxonomic groups can be enhanced through biodiversity-focused practices. However, other factors are also likely to drive species abundance and diversity, but have been less well explored, primarily due to a lack of data. Recent efforts to standardise ecological monitoring approaches at solar farms in Great Britain have enabled the amalgamation of biodiversity data from sites across the nation, creating a unique database containing information about multiple biodiversity groups. Using field data collected at 86 solar farms across England and Wales, plus site and landscape characterisation using a geographic information system, we assess how a range of drivers affect vegetation, butterflies and birds recorded within solar farms. In total, 289 plant species were recorded, along with 25 butterfly species (2589 individuals) and 81 bird species (6527 individuals). The abundance and diversity of these groups varied between solar farms and was explained by a combination of solar farm characteristics, landscape characteristics, other biodiversity present on site and survey methods used. Drivers differed across groups, but site management was linked to most aspects of biodiversity and soil type explained much variation in invertebrate and bird biodiversity. While some of the key drivers of biodiversity are largely fixed, site management emerged as the most actionable lever to enhance ecological outcomes. Our findings suggest that focused management can deliver biodiversity benefits, but the effectiveness may depend on site-specific conditions. Embedding biodiversity into the siting, design and management of solar farms is therefore essential to promote ecological benefits alongside renewable energy development.