Approximately 415,552m² of species rich grassland has been created, spread over 3-phases, 20 sites and 145 individual landscape plots, along the A19 corridor.
The team are working closely with the Durham Wildlife Trust and independent monitoring by ecologists Principal Component Analysis (PCA) has recently identified the following:
- Many plots are already examples of the Magnesian Limestone Grassland priority habitat type, with an additional 21 plots now being examples of the Road Verge of Conservation Importance priority habitat type.
- The other sites show enhancement with a very significant increase in species diversity across the network and the widespread occurrence of key indicator species.
- Of the 35 characteristic indicator species used in the Durham Biodiversity Action Plan Magnesian Limestone Grassland definition, 27 are now present along the route corridor. This includes several rare and declining species.
- The A19 now includes significant population of certain species, including Fragrant Orchid and Pyramidal Orchid. In relation to the latter, the route wide population now exceeds 5,000 plants. Several indicator species have been recorded for the project area for the first time because of effective management techniques.
- Habitat connectivity has been significantly enhanced. There is a number of locations within the project area where the restoration of the grassland habitat serves an important long-term corridor function.
- A recent invertebrate survey identified 4 new species for the county, 3 species with conservation status, and a NERC 41 priority species (see below).
Following the success of the scheme, proposals have been prepared to deliver further biodiversity enhancements along the network. 543,460m² across 196 individual locations through the A19 (T) corridor have been identified as having the potential to be converted to species rich grassland.
Invertebrate survey finds rare butterfly
The invertebrate survey results exceeded expectations with a wide variety of species confirming that the grassland management and enhancement measures also deliver important habitats for invertebrates. This included several new records for County Durham, such as Straight-fingered Chthonid (a pseudoscorpion), Berytinus montivagus (a stilt bug) and Elphacinus mesomelas (a delphacid hopper).
Another important species of note was the Dingy Skipper butterfly. This rare and declining butterfly is a NERC Act S41 Species of Principal Importance for the Conservation of Biodiversity in England which has been subject to recent conservation initiatives both nationally and in the North-east.
Following its discovery at a grassland in the north of the network further surveys will be undertaken to try to establish any additional colonies. Running north-south through the Magnesian Limestone it is possible that the A19 may prove to be a very important corridor for this species.