Current status
Blera fallax is a fly of native pine woods, where the larvae feed in wet rot-holes associated with the secondary decay of pine wood. Existing populations breed in wet pockets of decay in large pine stumps (minimum surface diameter about 40 cm). Less than 10% of large stumps in these areas have suitable wet pockets of decay. As decay proceeds wet areas dry out, thus fresh inputs are needed to ensure new breeding sites are available. In the remaining breeding sites there are very few trees or stumps of sufficient size where new wet pockets of decay might occur. The lack of breeding sites inhibits the recovery of B. fallax.
Until recently Blera fallax was recorded from only seven sites within the UK. These are in Aberdeenshire, Moray and Inverness-shire. It was regularly seen until the 1940s, but it has been recorded less than six times in the past 25 years. Most historical records are from Strathspey, centred on the area between Kingussie in the south and Grantown in the north. Recent surveys have shown that the distribution has apparently declined, with the only remaining populations on Speyside. In Europe, B. fallax is generally restricted to mountainous areas, where it is declining and probably under threat.
In Great Britain Blera fallax is classified as Endangered.
Current factors causing loss or decline
Inappropriate woodland management.
Paucity of breeding sites.
There is a potential threat from over collecting.
Current action
The Malloch Society, with support from SNH, is undertaking surveys for this species.
Some of the sites with recent records are within SSSIs and on the RSPB reserve at Abernethy Forest.
Action plan objectives and targets
Maintain the population size at all known sites.
Enhance the population size at all known sites by 2010.
Extend the range of Blera fallax into native pine woods.
Proposed actions with lead agencies
Policy and legislation
Consider adding Blera fallax to Schedule 5 of the Wildlife and Countryside Act 1981 by 2010. (ACTION: DETR, JNCC)
Take account of the requirements of B. fallax when considering felling and forestry schemes in native pinewood areas. (ACTION: FC, SNH)
Site safeguard and management
Where possible, ensure that all occupied habitat is appropriately managed by 2008, for example through site management agreements. (ACTION: FC, LAs, SNH)
Where possible, increase the available habitat at known sites and in adjacent areas, and attempt to link up existing fragments of habitat. (ACTION: FC, SNH)
Ensure that this species is included in site management documents for all of the SSSIs where it occurs. (ACTION: SNH)
Species management and protection
None proposed.
Advisory
Advise landowners and managers of the presence of this fly and the importance of beneficial management for its conservation. This should include notifying land managers of the location of important tree-stump breeding sites. (ACTION: SNH)
Develop and disseminate guidelines to protect Blera fallax for use with landowners; FC, LA, RSPB and SNH area staff; Highland Birchwoods and the Cairngorms Partnership. (ACTION: LAs, FC, SNH)
Future Research and Monitoring
Monitor the distribution and abundance of Blera fallax within its core areas. (ACTION: SNH)
Monitor and assess the quality and quantity of suitable stumps within the core areas. (ACTION: SNH)
Undertake surveys for B. fallax breeding sites in native pine woods in Strathspey, Deeside, Rannoch, and in Easter and Wester Ross by 2005. (ACTION: SNH)
Pass information gathered during survey and monitoring of this species to a central database for incorporation in national and international databases. (ACTION: SNH)
Communications and Publicity
Promote opportunities for the appreciation of this fly and the conservation of dead wood in Scottish woodlands. This should be achieved through articles within appropriate journals, as well as by publicity leaflets. (ACTION: SNH)
Links with other action plans
None given.
Publication details
Originally published in: UK Biodiversity Group Tranche 2 Action Plans - Volume IV: Invertebrates (March 1999, Tranche 2, Vol IV, p145)