Butterfly Conservation’s Conservation Officer, Rachel Jones, has revealed how working alongside the Dorset Wildlife Trust on the beautiful Isle of Portland has helped to protect the Silver-studded Blue butterfly.

In Dorset this butterfly is generally associated with the Dorset Heaths, but a rare ‘Cretaceous’ form of the Silver-studded Blues can still be found on the disused limestone quarries on the Isle of Portland. Silver-studded Blues are associated with bare ground which can be found in the quarries, this ground warms up quickly in spring, at a crucial time for the larvae to feed and develop.

Isle of Portland landscape. Photo: Steve Maskell

Over the last 40 years, however, the number of colonies and population sizes have dwindled from 26 colonies in 1994 to just nine in 2015!

In 2002 we became very concerned by the dramatically decreasing populations at Broadcroft Quarries (populations of 664 in 1997 to 39 in 2002), so were successful in obtaining a grant to create new breeding habitat for this stunning butterfly. In January 2003 a digger was used to scrape back the fertile topsoil that had built up over the years to expose the limestone, in total 26 ‘scrapes’ were created over 4.5 hectares.

Within two years the ants and larval foodplants had colonised scrapes and butterfly populations appeared to be responding well. These scrapes have helped to sustain populations at Broadcroft Quarries but in recent years some of the scrapes were becoming over-grown despite annual management by volunteers. It was clear further action was needed to boost populations.

Read Butterfly Conservation’s full article here