In their recent study, Ben Phillips and colleagues reveal the importance of road verges as habitats for pollinators, as well as the negative impacts of current management actions. But how can we improve the situation?
Most of us spend a good part of our days travelling on roads. The remains of the animals that stare back at us from the asphalt – the victims of collisions with traffic – suggest that roads are inherently bad for wildlife. But the landscapes beyond our roads have also facilitated the decline of many species, not least pollinators (e.g. bees, but also flies, beetles and more). Specifically the loss of flower-rich habitats and the use of pesticides have made agricultural landscapes increasingly difficult places for pollinators to live. For example, 97% of wildflower meadows have been lost in the UK since the 1930s. Surprisingly then, the network of habitats that border our roads (‘road verges’) may provide an incredible opportunity to feed and home our dwindling pollinator populations.
Road verges as pollinator habitats
Road verges variably consist of grass, scrub, trees, and hedges. In rural areas, they provide refuges from cultivation and agrochemical application that can be hotspots for flowers and pollinators. But traffic might negatively affect pollinators in road verges, e.g. due to pollution and collisions. And current road verge management does not generally consider pollinator (or nature) conservation, but is dictated by safety, aesthetics and costs (primarily cutting in spring and summer to maintain visibility for road users). Our study set out to understand the role of road verges as habitats for pollinators, and the impacts of traffic and management.
We surveyed flowers and pollinators along transects in road verges, hedges and adjacent fields at 19 study sites in Cornwall, UK. These covered a wide range of verge sizes (5-23 m wide), road types (unclassified roads to major roads), traffic densities (10-1,400 veh/h), and field types (various arable crops, pasture and agricultural meadows). Our results showed that road verges support considerably more flowers and pollinators than field interiors, which were consistently very poor for pollinators. This emphasises that vast areas of our agricultural landscapes provide very little for pollinators, making it vital to protect and enhance our road verges, hedges and other flower-rich habitats.
Managing our verges
But not all road verges are equal. Flower-rich verges had more pollinators, so clearly we should aim to increase the amount and diversity of flowers in road verges. However, we also found that verges along the busiest roads had (on average) half as many pollinators as verges along the quietest roads, and that there were fewer pollinators within 2 m of roads compared to deeper into verges. This is probably due to pollution and disturbance from traffic.
We also found that cutting road verges in summer massively reduces the numbers of flowers and pollinators, even weeks later. Routine management in our study area is typical for the UK and involves cutting verges in summer, i.e. when pollinators are most active. Although this is primarily carried out to meet safety requirements, the extent of cutting often far exceeds this. Primarily, the inner strip of verges alongside the road often needs to be cut to maintain visibility for road users. Given that fewer pollinators are found within 2 m of roads, we can cut this inner strip regularly without compromising the rest of the verge, which is more important for pollinators.
Based on our findings, we propose two main recommendations for management:
- Do not cut road verges during peak flowering times (i.e. delay cutting until autumn), except where required for safety (i.e. visibility splays).
- Prioritise beneficial management for pollinators on wider road verges (at least 2 m wide), roads with less traffic and areas away from the immediate vicinity of the road.
The wider context
The findings of our study strongly support Plantlife’s public campaign to manage road verges for nature conservation. Plantlife have done a fantastic job of championing the issue, gathering over 70,000 signatures and working with organisations across the UK to implement their simple and effective management guidelines. Their guidelines are based around the message: “cut less, cut later”, i.e. delay cutting verges to allow plants to flower and set seed, except where required for safety. There are some additional management actions that will benefit pollinators, which we recently summarised in a report for Buglife, e.g. (iii) leave areas uncut at the back of verges to provide habitats in which pollinators can nest and overwinter, and (iv) cut sections of road verge at different times so that there are always some undisturbed areas for pollinators.
In reality, managing our road verges for pollinators will require a fine balancing act between nature conservation, safety guidelines, management costs, existing contractual obligations, and public demand for tidiness. Yet it remains a major opportunity, especially because the transport networks along which we live and move are ubiquitous: enhancing them for wildlife, even slightly, would provide significant collective benefits. Given concerns about declines in pollinators, insects and biodiversity in general, it is an opportunity that we surely must take.
Read the full open access Research Article, Road verges support pollinators in agricultural landscapes, but are diminished by heavy traffic and summer cutting, in Journal of Applied Ecology.