Planting Wildflowers Around Solar Panels Could Boost Bumble Bee Numbers

New research shows that simple changes to how UK solar parks are managed could boost ground nesting bumble bee populations in the parks and surrounding areas, providing an additional benefit on top of renewable energy.

Researchers at Lancaster University, UK, investigated different scenarios to see if ground-nesting bumblebee populations could be better supported. The pollinators are in drastic decline across Europe – their numbers have fallen by 17 per cent since the early twentieth century.

PhD researcher Hollie Blaydes says, “Our findings provide the first quantitative evidence that solar parks could be used as a conservation tool to support and boost pollinator populations. If they are managed in a way that provides resources [such as wildflowers], solar parks could become valuable bumble bee habitat.”

Farmers would also reap the benefits of these parks upping their floral and nesting offerings.

“In the UK, pollinator habitat has been established on some solar parks, but there is currently little understanding of the effectiveness of these interventions. Our findings provide solar park owners and managers with evidence to suggest that providing floral and nesting resources for bumble bees could be effective,” Blaydes says.

Simulating different models of bumblebee foraging, the researchers found that large, elongated and resource-rich solar parks could boost bumble bee density up to 1km outside of the parks themselves.

This would bring pollinator services to crops in surrounding agricultural land – which locals could further take advantage of by planting pollinator-dependent plants like basil and courgettes.

Why do solar parks make promising habitats for bees?

In the UK, solar parks are often located within intensively managed agricultural landscapes, raising the potential of solar parks as refuges for bumble bees.

The area of land used for solar parks in the UK is also growing, increasing the potential to harness this land for additional benefits. Ground-mounted solar parks currently take up 14,000 hectares. For the UK to meet net zero targets, the Climate Change Committee projects that there will need to be an additional 54GW of solar photovoltaic, meaning a land use change of 90,300 hectares for solar parks.

There are barriers to solar parks being managed in ways that benefit bumble bees and other wildlife. For instance, there are costs associated with establishing and managing habitats for pollinators and there are currently no economic incentives for the solar industry to do this.

What’s next for protecting pollinators?

Post-Brexit agricultural bill payments could reward ecosystem services, incentivising solar park owners to let their fields grow into wildflower meadows.

Business structures could also prove to be a hinderance. Hollie Blaydes explains: “Management of solar parks is often outsourced to external companies where contracts are typically around two years long. This, along with frequent changes in ownership, means that management regimes could be changed as the solar park or management contract changes hands. This could be challenging when trying to establish and maintain habitats over longer time scales.”

In the study, in order to understand how solar park management could impact bumble bee density within solar parks and surrounding areas, the researchers used a geographic information system (GIS) to create solar parks of different sizes, shapes and management approaches based on real UK examples in real UK landscapes.

This GIS was combined with a state-of-the-art pollinator model called Poll4Pop which predicted bumble bee density and nest density inside the solar parks and surrounding buffer zones.

They then used statistical analyses to investigate differences in bumble bee density and nest density across the different solar parks in the model.

To test the findings from their model, the researchers call for data to be collected on real-world solar parks to better understand pollinator response to management schemes.

The researchers specifically looked at ground nesting bumble bees and did not consider other important pollinators such as solitary bees, hoverflies, butterflies and moths. The different resources and foraging behaviours of these groups would require alternative modelling approaches to understand how they might benefit from solar park management.

Presenting her research at the Ecology Across Borders conference on 13 December, Blaydes and her team made the case for collecting real-world data at solar parks to better understand the impact of different management styles.

Other important pollinators such as solitary bees, hoverflies, butterflies and moths deserve the same attention if we’re to bring our solar power into harmony with the natural world.