Roadside verges, Wiltshire

Overview

The floral biodiversity of roadside verges along UK highways is typically an unknown quantity. Verges frequently consist of bare ground, scrub and tall ruderal habitats, and are often covered with litter. Occasional road kill (including pole cats) can be found, and there is generally a lack of beneficial conservation management in place.

Project brief

Ecosulis was asked by Skanska/Highways England to assess plant biodiversity along two stretches of highway in Wiltshire. Using the Biodiversity Quality Calculator (BQC), road verges were assessed as species poor grassland, dominated by grasses and scrub. To boost biosversity, Ecosulis recommended the use of appropriate grass seed mixes, better management of scrub areas, and rubbish removal.

YEAR

2016

Impact

manage Biodiversity

An increase in plant biodiversity and species rarity.

Protect Habitats

A conversion of species-poor open grassland and scrub to species-rich grassland.

empower-us-to-act People

Informed management decisions and occasional rubbish removal.

How we added value.

Biodiversity Survey & Design: sites of biodiversity assessment

The Plant Biodiversity Survey was conducted along two stretches of highway: a 5-mile stretch of the A330 near Salisbury (46ha) and  a 3.5-mile stretch of the A36 near Brickworth (36ha). At both sites, 1m x 1m quadrats were surveyed at intervals as close to 0.5 miles.

Biodiversity Valuation: the Biodiversity Quality Calculator

Biodiversity is complicated and cannot be measured by using species richness data alone. Therefore, Ecosulis developed the Biodiversity Quality Calculator (BQC). By using the plant quadrat data to calculate a wide range of biodiversity measurements, the BQC could assess the biodiversity baseline along the two highway stretches.

Result: plant biodiversity

Roadside verges were patchy with tall ruderal and scrub species being recoded within over half of the quadrats. The habitat was assessed as species-poor neutral grassland, due to the limited species diversity and the domination of perennial rye grass, fescue and bramble scrub. Two positive indicator species (devils bit scabious and meadow vetchling) were rare.

Result: effects of seed mixes

Ecosulis provided a forecast in the change in biodiversity as a result of using different seed mixes. Based on the plant assessment, Ecosulis recommended seeding road verges with basic and special general meadow mixture. While this does not provide an increase in the species, it would result in an increase in species rarity.

Want to learn more about rewilding and nature recovery?

Read more insights or explore our previous work.