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.