The Two Moors Threatened Butterfly Project

Marsh Fritillary

The Two Moors Threatened Butterfly Project was one of Butterfly Conservation’s longest running landscape scale conservation projects, working to reverse the declines in three of our most threatened butterfly species, the Marsh Fritillary, High Brown Fritillary and Heath Fritillary across Dartmoor and Exmoor from 2005 to 2016.

In the south west, these species live on three main habitat types:

  • Wet grassland or ‘Rhos’ pasture found in valley bottoms
  • Steep bracken dominated slopes
  • Heathland / moorland edge in sheltered valleys

All three species have suffered significant declines in the last 40 years or so, primarily due to habitat loss caused by changes in land management practices, reduced grazing levels and often a lack of management or abandonment of the site. Loss of foodplants resulting from shading by invading scrub or dense (undergrazed) swards of purple moor grass can also be an issue.  These fritillaries have highly specialised habitat requirements, and management is required to create and maintain suitable conditions. Further details on management for these species can be found on the relevant butterfly factsheets below..

Marsh Fritillary Habitat

The Project has been working at a landscape scale, restoring and re-connecting areas of suitable habitat by working with farmers and landowners, providing help and advice in habitat management, sourcing funding for required management and organising practical works. The project finished in 2016, coinciding with the launch of a new Butterfly Conservation project called ‘All the Moor Butterflies’, which aims to continue and expand on the work of the Two Moors Threatened Butterfly Project.

Project Aim

The main aim of the Two Moors Threatened Butterfly Project was to reverse the declines in the three threatened target species by restoring and re-connecting areas of suitable habitat. The project worked with farmers and landowners, providing management advice and support by helping to source funding for required management, and by organising practical work.

Methods

Assistance was provided to landowners wishing to enter into agri-environment agreements with Natural England. These agreements support landowners in undertaking wildlife friendly management on their land, and can help to fund important management works. Agri-environment agreements have been a key mechanism for the delivery of targeted management across whole landscapes, but where this support was not available, the project worked to ensure that necessary management was still carried out, for example by working with volunteer groups to clear scrub from important breeding areas.

The Project was delivered through a combination of:

  • Site visits to assess habitat quality, provide advice and conduct monitoring
  • Provision of support and advice to landowners and help with accessing funding for management works
  • Provision of support to Natural England staff by assisting in agri-environmental applications and ensuring appropriate management prescriptions are included in agreement terms
  • Organisation of training events for conservation professionals, landowners, volunteers and contractors
  • Delivery of practical conservation work to restore and improve habitats
  • Provision of guided walks and other public events to create species awareness

 

Results

  • Site engagement and habitat management advice  In total the project has engaged with 292 sites across Dartmoor and Exmoor (178 on Dartmoor, 114 on Exmoor) and provided advice on the management of over 1800ha of habitat to improve habitat suitability for fritillary butterflies, increase connectivity between habitat patches and increase the extent of potential breeding patches.
  • Species monitoring has been carried out at more than 100 sites annually.
  • Support with entry to agri-environment agreements has been offered to landowners and Natural England Advisers to assist in the set-up of 112 Higher Level Stewardship agreements.
  • Management, including the (re)introduction of grazing, scrub removal, swaling, bracken management and fencing, has been carried out across more than 1500ha of habitat.
  • Engagement with volunteers  An average of 20 volunteer work tasks have been led annually over the past six years, amounting to a total of over 1100 volunteer days working to improve and restore fritillary breeding areas.
  • Training workshops  An average of 5 workshops have been led annually to teach volunteers to undertake monitoring of target butterfly and moth species.
  • Publications  The project has been involved in several key publications including Conserving Britain’s Fastest-Declining Butterfly (British Wildlife Dec 2015) and Landscape Scale Conservation for butterflies and moths (BC publication). A case study of the project’s work on Marsh Fritillary habitat on Dartmoor is included in this publication.

This landscape-scale approach to management has shown success in managing for the target species.

 

Response of the butterflies

The response of the butterflies has been positive overall, with all target species either increasing or remaining stable over the project period, against a backdrop of national decline.

 

Marsh Fritillary Population trend over the 11 year period: Dartmoor - 721% Increase

Marsh Fritillary web data 2005-2016

 

High Brown Fritillary Population trend over the 14 year period (since 2002): Dartmoor - Stable, Exmoor - 646% Increase

High Brown Fritillary 2002-2016

 

Heath Fritillary sites and colony numbers 2004-2016

Heath Fritillary sites and colony numbers 2004-2016

 

    Work Party- Two Moors

Managing habitat for the target species has helped maintain and restore habitat for other species such as Narrow-bordered Bee Hawkmoth, Pearl-bordered Fritillary and Small Pearl-bordered Fritillary, as well as a wide range of other flora and fauna.

Public engagement activities have helped to increase awareness and understanding about butterflies and their habitat requirements through the provision of guided walks and workshops.

 

Contact

Jenny Plackett, South West Senior Regional Officer

Funders

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