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Solar farms could become important refuges for bumblebees in Britain, a new study reveals—though their benefits only go so far.

In the first study to investigate the role of solar farms in future biodiversity conservation, a research team, from Lancaster University, the UK Center for Ecology & Hydrology and the University of Reading, set out to discover if the UK's existing solar farms could support bumblebees in the face of a changing countryside. The findings are in the journal Global Change Biology.

They found that solar farm management—wildflower margins versus turf—was the main factor influencing the number of bumblebees within solar farms themselves.

Their new modeling suggests bumblebee numbers within solar farms could more than double (increase by 120%) if solar farms are managed for biodiversity, with wildflower margins providing a rich source of food for the bees. This increase is when compared to solar farms just covered with turf grass.

"Our results indicate that well-managed solar farms could provide refuges to help protect localized bumblebee populations against landscape changes happening beyond the site boundaries," said Dr. Hollie Blaydes, Senior Research Associate at Lancaster University. "We expected to find that solar farms with more resources would support more bees, but we were also interested in how this management interacts with wider land use changes."

The researchers applied a novel high-resolution modeling technique to predict how Britain's existing 1,042 solar farms may play a role in supporting bumblebee numbers in the coming decades.

They used and investigated three previously established (based on the Representative Concentration Pathways and Shared Socioeconomic Pathways) of what landscapes in Britain could look like based on 'sustainable," "middle-of-the-road" and "fossil-fueled development" socio-economic scenarios, downscaled from 1km to a highly detailed 10m square resolution.

Across these scenarios, the number of different habitats in a landscape varies, as does management of these habitats, with consequences for bumblebee foraging and nesting opportunities. All futures see a decrease in agricultural land area surrounding solar farms compared to the present day, driven by factors ranging from changing diets to increased urbanization.

Dr. Blaydes said, "We took existing land use futures maps and downscaled them to a resolution that is more relevant to bumblebees. Then, we added features, such as hedgerows and wildflower patches, which are important landscape elements for bumblebees and combined the maps with a pollinator model. The model predicts how bees use these landscapes based on foraging and nesting resources. This aspect of the work was particularly novel—it is unusual for modeling like this to be done in such detail."

Their results suggest the bee-boosting effects of the management of solar farms are largely constrained to the solar farms themselves—and have a limited and localized impact across a large wider landscape.

Landscape composition around solar farms were found to have a greater influence on bumblebee densities in the foraging areas surrounding solar farms.

Modeling for a "sustainable" future scenario where more bumblebee food resources and habitat are put back into the landscape would have the most positive impact on bumblebee densities across a wider landscape, including foraging zones around existing solar farms.

Alona Armstrong, Professor in Energy and Environmental Sciences and co-author of the study, said, "While benefits from solar farms for bumblebee densities may be limited to the local scale, our findings help to show that site management plays a role in supporting bumblebee populations. Solar farms could be considered as an emerging tool in conservation to help protect populations of bumblebees into the future.

"If we are going to need additional solar farms to meet our national renewable energy commitments, then strategic siting of solar farms could be considered to connect bumblebee habitats or provide bumblebee resources where they are otherwise limited."

Dr. Blaydes said, "Solar farms can be refuges for bumblebees in the present day and in the future and could play a part in mitigating habitat loss—if managed well. But, solar farms alone will not be able to counteract the effects of all future land use changes on bumblebees and other biodiversity."