Specialist Moths in the Brecklands

Forester

Thanks to project work in the Brecklands landscape early successional habitat has been created which benefits a suite of threatened moths. 

Breckland is a unique area of open heathland, forestry and agricultural land straddling the western borders of Suffolk and Norfolk.  A ‘Breck’ is a temporary field which is cultivated for a few years then abandoned to enable fertility to recover. 

The presence of bare ground and early successional habitats is an important feature of Breck heathlands and dry grassland and can provides habitat for many scarce insects and plants including specialist moths. Grey Carpet and the micro-moth Basil Thyme Case-bearer are both confined in Britain to breeding in Breckland. The Brecks are also an important landscape for several other moths including; Lunar Yellow Underwing, Forester, Tawny Wave and Marbled Clover.

For all these species disturbed ground is known to be an important factor in their occurrence and in recent years management by sheep grazing combined with wet summers has contributed to a decline of bare and disturbed ground on Breckland grass-heath sites and on forest rides.

Project Aim

The aim was to use a range of ground disturbance techniques to create early successional habitat, suitable for a suite of threatened moths across the landscape.

Methods

  • In 2008-09 Butterfly Conservation created 59 bare ground plots using five different treatments across 15 sites in Suffolk and Norfolk, where there was no recent evidence of ground disturbance. 
  • The five treatment types used were; rotovation, forest ploughing, agricultural ploughing, disc harrowing and turf stripping
  • Plots were visited in 2009 and 2010 and half visited again in 2011 to survey for four of the target moths and two larval foodplants.

Read The Full Report

For more detailed information about this project and others across the UK please read the full report: Landscape-scale Conservation For Butterflies And Moths: Lessons From The UK

Results

  • The Grey Carpet foodplant, Flixweed, appeared on 34% of treatment plots with Grey Carpet was found on 13% of plots.
  • The Basil Thyme Case-bearer foodplant appeared on one plot.
  • Lunar Yellow Underwing larvae were found on eight of the 12 plots surveyed.
  • The Forester moth was attracted to the abundant nectar sources on plots and was found on 20% of plots.
  • The various treatments all showed varying success, with 51% of plots having records of target moth or larvae.
  • It was difficult to predict the plant species composition as this depended on a range of factors including soil type, vegetation and land management.
  • Volunteer involvement was vital to the work and nearly 70 volunteer days were contributed.

Success!

Almost all the different treatment plots created an abundance of nectar from a variety of plants through spring-autumn; this is a major factor in attracting moths, butterflies and other nectaring insects. Mechanical soil disturbance created highly suitable conditions for a range of moths on some plots.  The target moths occur in low densities across the landscape so bare ground creation work is only required at a low level to maintain and increase species, therefore to ensure the presence of some suitable conditions plots should be managed each year on rotation using a range of treatments.

Funders

SITA Trust, WREN, HDH Wills Charitable Trust, J Patson Charitable Trust, Norfolk Biodiversity Trust and Butterfly Conservation Members and Donors. 

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