Securing the Large Blue Landscape in the Polden Hills

This funded project aims to help secure the Large Blue in the Polden Hills Landscape in the longer term. 

The Large Blue Maculinea arion is the UKs rarest butterfly and is globally endangered.

The Polden Hills supports nearly 80% of the Large Blue populations in Britain. The aim of this landscape-scale project is to help secure the Large Blue butterfly in the Polden Hills network by increasing its population and distribution following a programme of habitat management.

Large Blue Ecology and History

The Large Blue breeds in well drained unimproved grassland, predominately in Limestone or coastal grassland. The adult lays its eggs on Wild Thyme Thymus polytrichus flower heads which are the larval foodplant. Breeding success is best in grasslands with a short turf where the host ant Myrmica sabuleti is abundant. Please see the Large Blue Factsheet for more information on the species ecology, habitat and life-cycle.

The Limestone grassland sites in the Poldens Hill are its current stronghold in the UK. Historically this species became extinct in the UK through a combination of factors that led to the loss of unimproved grassland through habitat destruction and abandonment and changes in management.

Since the Large Blue became extinct in the UK in 1979, the combination of research and conservation has resulted in the most successful insect conservation programme in the world. Since its re-introduction to sites in the UK in 1984 the number of successful colonies in the South west has increased to a total of 30 in 2008.

The project started in September 2014 and will run until February 2016.

Project Aims:

The project aims to secure the Large Blue butterfly by increasing its populations and distribution across a network of 14 previously occupied and currently occupied sites.

We are specifically aiming to:

• Restore three hectares of suitable breeding habitat to strengthen the Large Blue numbers at nine sites and help the Large Blue recolonise five former, but currently unoccupied sites.   

• Help mitigate against the impacts of climate change. Wild Thyme can be subject to drought in particularly long, dry spells of weather, which has a detrimental impact on larvae. We will be trialling the seeding of Marjoram, an alternative Large Blue foodplant, used usually on locally hotter sites, it is more drought resistant and available later in the season.

• Support the expansion of the rare Liquorice Piercer moth by planting its foodplant Wild Liquorice in areas where it has been lost.

 Project Methods:

• Habitat assessments to guide the site management (scrub management and grazing regimes) and to determine locations of Marjoram seeding.

• Restoration and maintenance of limestone grassland through scrub management and follow up control of ruderals.

• Installation of fencing to allow conservation grazing so that suitable habitat can be sustained in the future following the end of the project.

• Marjoram seeding on eight project sites.

• Planting Wild Liquorice plants on sites where the plant has been lost to support the expansion of the Liquorice Piercer moth.

• Monitoring of Large Blue populations to assess the response of management.

• Community workshops aiming to recruit local volunteers to help to assist with conservation management and monitoring. Volunteers are crucial in helping to secure the butterfly in the landscape in the longer term.

Project Delivery:

The project is managed by Butterfly Conservation’s Species Team based at our Head Office, overseen by Dr Caroline Bulman. Conservation Officer, Rachel Jones manages the delivery of the site restoration work, which includes scrub management, ruderal weed control and community engagement. Local contractors, project partners and volunteers carry out this vital work.

Highly experienced Large Blue contractor David Simcox is leading the research that underpins the project. Using site knowledge from ant surveys, Large Blue monitoring and habitat assessments he will provide carefully targeted management advice on the scrub clearance and grazing regimes.  He will also be leading the collection and seeding of the Marjoram together with Sarah Meredith.

Project Funders and Supporters:

Biffa Award, Natural England, Butterfly Conservation Somerset and Bristol Branch, University of Oxford and all those who generously contributed to Butterfly Conservation Match Pot Appeals. 

The project would not be possible without the support of the partners in the East Poldens Large Blue Landscape Partnership and the private landowners. 

The East Poldens Large Blue Landscape Partnership work together to restore the East Poldens landscape, including re-establishing a viable Large Blue butterfly population that formally went extinct in the UK in 1979. The Partnership consists of Butterfly Conservation, J&F Clark Trust, Millfield School, National Trust, University of Oxford, Somerset Wildlife Trust and South Somerset District Council, with support from Natural England.

Where to visit:

The best site to see the Large Blue in flight is at the National Trust site, Collard Hill http://www.nationaltrust.org.uk/article-1356396112443/. Please use the link to find out more and how to get there. Other project sites are either closed to the public during the flight season or on private land. 

For more information or if you would like to help volunteer on the project by helping with practical conservation work or monitoring please contact Rachel Jones by email; @email or telephone; 01929 406018.

To find out more about Large Blue Action Group events please visit the events page here.