Wildlife Trust surveys Cambridgeshire’s protected roadside verges

Britain has 370,000km of roads, from motorways to minor rural lanes, and many are bordered by verges - these strips of land collectively make up an enormous linear nature reserve.

Many road verges are not sprayed with herbicides and other chemicals, so left to their own devices these strips of land can develop into wildflower-rich substitutes for the traditional wildflower meadows and cornfields that have been cumulatively lost since the 1950s. Around 700 species of wildflowers now grow on British verges, everything from swathes of buttercups, ox-eye daisies and poppies to rare orchids. Councils have a responsibility to maintain highways in good condition - visibility and safety comes first, but there's no doubt that over-intensive management can have an adverse impact.

Slowly but surely the sterile neat-and-tidy ideal of the verge as manicured lawn is being challenged, particularly on motorways, rural verges, and some urban highways. Species-rich verges enhance the local character and visual interest of roads for drivers while wildflower-rich verges support abundant populations of insects and mammals such as voles, in turn attracting predators such as kestrels and barn owls.

The Wildlife Trust in Cambridgeshire are co-ordinating a two-year survey of 80km of protected road verges (PRVs) in Cambridgeshire for Cambridgeshire County Council; now into the second year, during last year’s surveys the presence of county rarities crested cow-wheat and sulphur clover on some sites was confirmed.

Laura Osborne, the Trust's living landscapes manager in Cambridgeshire says: “We’ve surveyed some wonderfully species-rich verges and also identified some that require a change in management in order to maximise their benefit for biodiversity; we also found evidence of badger and hedgehog and heard many yellowhammers in the hedgerows. These protected verges are highlighted by posts at either end of the site so people should look out for their local PRVs and appreciate them! The results will help Cambs county council review their management of PRVs.”

In north Cambridgeshire in the area known as John Clare County, 39km of road verge connect county wildlife sites, sites of special scientific interest and national nature reserves, so are key in the landscape.

Managed by Peterborough County Council these are currently cut once a year in early autumn. In order to increase the species-richness of the verges, the trust has worked with the council and ecological consultant Sarah Lambert to write a new management plan - increasingly milder winters and longer growing seasons is leading to a greater biomass of grass in early spring which can swamp wildflowers which are starting to shoot, and hindering the growth of low-growing plants.

Last year some sections of verges were cut in spring as well as autumn, and volunteers trained to undertake monitoring of key species in the sections with the additional cut: the survey will be repeated next year to give the verges a chance to respond. If these sections are seen to improve then the spring cut will be applied to the whole length and maybe other verges also.

There are huge opportunities to create more space for nature - opportunities that are all too often missed. It's common for many verges to be mown too frequently and the cuttings left in place, which first creates a physical barrier to growth, then increases the soil fertility as the cuttings decompose, which gives an unnatural advantage to the most competitive plants. Spoil from ditch clearance is often spread across verges with similar effect. Conversely, too little mowing can also be a problem; many verges are left unmown and the strips of grassland are lost as they grow into scrub.

A road verge well managed for wildlife can be a set of parallel worlds each offering different niches for wildlife. Tall, wide, diverse, native hedgerows at the back of the verge, complete with trees, can grade through infrequently trimmed tall herbs and tussocks to grassland meadows mown once or twice a year, where the cuttings are collected and removed. Here mowing is best done in late summer, to allow seed to ripen and insect lifecycles to complete, or even later where soil is poorer. Removing cuttings simulates wild grazing and reduces fertility in the soil, maintaining more natural conditions that support a wider diversity of wildflowers and the invertebrates that rely on them.

There are roadside nature reserves across the UK that set the standard for roadside habitat, but it's important to call for better management for all verges to achieve a national Nature Recovery Network.

Find out more at www.wildlifebcn.org/john-clare-country.

Becoming a member of the the Wildlife Trust is a great way to protect local wildlife at www.wildlifebcn.org/become-member.