28 May 2012
A hillside covered in wildflowers could become a key site for the country’s rarest butterfly with help from a grant from Natural England.
Rough Bank, which overlooks the Slad Valley in Gloucestershire, has been bought by Butterfly Conservation with the hope of developing the grassland into a key breeding site for the rare large blue butterfly.
The large blue became extinct in the UK in 1979 and is globally threatened. But hillside which is already home to four other blue butterfly species.after the discovery of its reliance on a species of red ant, it has been successfully reintroduced at a number of sites across southern England.
The rare large blue butterfly is set to be reintroduced in the Cotswolds on the 44-acre hillside which is already home to four other blue butterfly species.
Head of reserves at the charity John Davis said: "It was naturally a site for the large blue, so it is inherently suitable and is already an important site for the small blue, chalkhill and Adonis".
Natural England paid for half of the cost of the land with a £100,000 grant. The money will be used to clear some scrubland, graze the site with cattle and ensure the right species of the red ant is present. Public access and flood drainage systems will also be installed.
Natural England’s Biodiversity and Landscape Principal Adviser Ben McCarthy said:
“The acquisition means the site will be managed to the highest level, maintaining suitable and secure conditions for re-introduction of the large blue butterfly and contribute to the suite of NNR limestone grasslands under co-ordinated NNR management in this area.
“It will also maintain an important resource within the Cotswold Grazing Animals Project and the site will benefit from improvements to visitor access which mean more people can enjoy this wonderful area” he added.
The Cotswolds Natural Area overlies a band of limestone stretching from Somerset to Warwickshire. An extensive semi-natural habitat in the Cotswolds is unimproved grassland and the Natural Area supports over 50% of the national resource of limestone grassland characterised by upright brome and tor grass. The limestone grasslands are rich in plants and invertebrates, particularly butterflies, and are the national stronghold for Duke of Burgundy butterfly.
The butterfly lays its eggs on wild thyme.
Once hatched, the caterpillars feed on the plant before dropping to the ground where red ants mistake them for ant larvae and take them into their colonies.
There the butterfly larvae feed on ant larvae until they emerge as butterflies.