Understanding the value of our roadside hedges and verges.
The Cornwall AONB Unit is working in partnership with the Environment & Sustainability Institute (University of Exeter) to study hedges and road verges. The four year project is exploring their role in conserving nature and providing benefits to people, and investigating how to manage them in the best way possible.
At last count, there were 4,616 miles (7,430 kilometres) of roads in Cornwall. Narrow lanes, tall hedges and stone-faced earth banks are deeply characteristic of the Cornish landscape. In many cases, they mark ancient routes or boundaries, with some hedges dating from as far back as 6,000 years ago. Whilst roads undoubtedly have some negative impacts for nature, they also provide important potential habitat because most roads are bordered by a thin strip of land in the form of a hedge or verge. These roadside habitats provide incredible untapped potential because (i) They cover a substantial area of land when summed across Cornwall and the UK, and (ii) There is little or no competition for their use. Beyond their clear purpose as boundary markers, roadside verges and hedgerows support a surprising diversity of life and are home to many rare and threatened species. For example, the charity Plantlife report that over 800 plant species can be found in UK roadside hedges and verges, including 100 ‘threatened’ or ‘near threatened’ species.
Roadside habitats are therefore important for providing:
Food and shelter for many species (from mosses and ferns to bats and bees).
A vast network along which species can move and disperse.
Benefits to humans, such as capturing vehicle pollutants, slowing rainwater run-off and, in theory, could provide natural beauty to road users.
Since September 2017, the Cornwall AONB has been working in partnership with the Environment & Sustainability Institute at the University of Exeter to study these roadside habitats. The project is funded by the Natural Environment Research Council (NERC) and is being carried out by Ben Phillips, a PhD student at the University of Exeter’s Environment & Sustainability Institute in Penryn.
The general questions that we are looking to answer are:
How do roadside hedges and verges support wildlife?
What benefits to humans are provided by roadside hedges and verges?
How can we improve management of roadside hedges and verges?
The project is now one year in and will continue until 2021. Over the past year, we have looked at the role that hedges and road verges play in supporting plants, flowers and pollinators in farmland. This is important because insect such as bees are crucial for the pollination of many crops and of wild plants, but have suffered declines in recent decades. The early findings show that hedges and road verges are essential in providing food (flowers) for pollinators in farmland, as there is often very little food for pollinators within fields. However, the way in which these are managed has a big impact on the amount of flowers provided, and other factors such as high traffic on roads can cause pollution and disturbance which probably affect the value of road verges to pollinators. We have also begun to consider the broader range of benefits that are provided to people. For example, rainwater may be slowed and absorbed by roadside vegetation, reducing flooding, soil erosion and contamination of water sources.
Over the next two years, we plan to develop a set of management guidelines for road verges in the County. We will also be further exploring some of the negative impacts of roads on wildlife in road verges, such as the impact of pollution, and how to make best use of road verges given this. Finally, we aim to learn about people’s attitudes to road verges and different management options, as well as barriers and opportunities for changing management. The aim is to find a practical way forward to making our roadside hedges and verges a positive space for nature that can benefit both people and wildlife in the region.
To find out more about the project, contact Ben at B.B.Phillips@exeter.ac.uk.