New Minsmere heathland attracts rare Silver-studded blue butterfly
19/03/2007 00:00:00
Minsmere heathland
- The arable reversion fields at Minsmere cover 203 hectares, of which 122 hectares are being reverted to acid-type grassland and 25 hectares to heathland. A further 56 hectares are still to go through the reversion process. The UK Biodiversity Action Plan includes targets for the re-creation of both heathland and acid grassland.
- The Suffolk Sandlings heaths formerly stretched from Lowestoft to the Orwell Estuary. Pockets of heathland remain, with one of the largest being around RSPB Minsmere, Westleton Heath and Dunwich Heath National Trust.
- Surveys of the silver-studded blues, Plebejus argus, at Minsmere were carried out by RSPB staff with the assistance of volunteers from Butterfly Conservation.
- The silver-studded blue butterfly is listed as a UK Biodiversity Priority species by the UK government. Conservation organisations, like the RSPB and Butterfly Conservation, are working to maintain existing populations and manage heathland to allow natural re-colonisation.
- The silver-studded blue butterfly is distinguished by silvery-blue scales within the black spots on the rear of the underwing. This is what gives them their name, but the spots can be difficult to see in the field.
- The unusual beetles discovered on the arable reversion fields at Minsmere are: Polystichus connexus , Harpalus smaragdinus , Amara equestris , Amara consularis , Calathus ambiguus , Harpalus attenuatus , Amara fulva , Syntonus truncatellus , Harpalus anxius , Laemostenus terricola and Harpalus rufipalpis . None of which have English names.
- Lowland heathland and chalk grassland have suffered major loss and degradation since the 1800s. More than 70% of lowland heathland has been lost from Britain since the 1800s, and the areas that are left are often small, isolated and becoming degraded without traditional management. Chalk grassland has been similarly affected with 80% lost to farming since the 1940s.
One of the UK’s rarest butterflies has been found thriving at RSPB
Minsmere. A colony of silver-studded blue butterflies was discovered on former farmland that had been transformed into traditional Sandlings-type heath. Specially created to attract unusual breeding birds such as woodlark and stone-curlew, the RSPB thought the heath would allow other species to move in from other surviving pockets of heath.
The discovery of the silver-studded blue butterfly has proved them right and illustrates how efforts to preserve habitats help a wide range of wildlife. The RSPB has also contributed to the Biodiversity Action Plan, which aims to stop the decline of the country’s species and habitats by 2010.
Minsmere is a world famous bird site but the reserve has an increasingly important insect population. In addition to the butterflies, several unusual beetles have been discovered and the reserve now boasts around 1,000 different species of moths and butterflies.
In the UK silver-studded blue butterflies are limited to areas of heath and grassland in southern and eastern England and around the coast of Wales. They require a mix of short, sparse vegetation, usually maintained by grazing, burning or mechanical cutting, in addition to mature vegetation on which to sun themselves. This mix is unusual, but on the Suffolk coast there are relatively big colonies on several heaths, including RSPB reserves at
Minsmere and Westleton heaths.
The RSPB bought several arable fields at
Minsmere in the 1980s which have slowly been converted to a mix of heathland and acid-type grassland, typical of the heaths of the Suffolk Sandlings. The 200 hectares at
Minsmere is just a small fraction of the old Sandlings heathland, which used to stretch along the Suffolk coast from Lowestoft to Ipswich. Silver-studded blues have an unusual lifecycle; the caterpillars are collected up by black ants and taken to their colonies. The caterpillars are then `milked’ for sugary secretions, which they exude from special glands. The ants, in their turn, protect the caterpillars inside their nests, where they pupate and finally emerge as mature butterflies.
Mel Kemp, heath land warden at Minsmere, said: ‘This is a fine reward for many years of hard work to re-create heathland. The heather is fantastic in late summer, and it’s great to see these lovely butterflies spreading into new areas after decades of habitat loss.’
RSPB researchers also found several uncommon beetles that depend on open areas with short vegetation and bare ground.
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