Current status
Osmia xanthomelana is a large mason bee with a conspicuous covering of tawny hair. It builds its nest cells from mud pellets which it gathers at seepage areas on cliffs and banks. The nest is constructed either at the base of grass tussocks or in ready-made cavities. The cells are provisioned with pollen gathered from bird's-foot trefoil or horseshoe vetch. The flight period is from May to July. This species is typical of a number of insect species which are closely associated with the south-facing, soft-rock cliffs of southern England.
Osmia xanthomelana is probably our rarest solitary bee, there being post-1970 records from only 3 ten km squares. Two localities are on soft-rock coastal cliffs in the Isle of Wight and the third is on soft-rock coastal cliffs of the Lleyn Peninsula in North Wales. Even at its main location on the Isle of Wight it is difficult to find, with an estimated population of fewer than 50 individuals in any one year. It was formerly distributed widely in England and Wales, with a total of 21 ten km squares recorded, although most records are from the 19th and early 20th centuries. It has never been considered a common species. It is rare and sporadic in southern and central Europe.
In Great Britain this species is classified as Endangered.
Current factors causing loss or decline
Cliff stabilisation.
Intensification of agricultural systems at the top of soft-rock cliffs, leading to increased nutrient input to the cliff faces as fertilised agricultural land makes its way down the cliff. This increased input of nutrients results in a coarsening of the vegetation, and rapid shading out of both nesting areas and forage plants.
Scrub encroachment.
Current action
This species has been the subject of an NE Species Pre-Recovery Project which has led to limited habitat management at its major known site on the Isle of Wight.
CCW commissioned a survey of former localities and suitable habitat on the Lleyn Peninsula in 1995.
Action plan objectives and targets
Maintain populations at all known sites.
Enhance the population size at all known sites by 2010.
Restore populations to suitable sites to maintain five viable populations within the historic range by 2010.
Restore populations to suitable sites to maintain 20 viable populations in the long term.
Proposed actions with lead agencies
Policy and legislation
Incorporate the requirements of Osmia xanthomelana in relevant Shoreline Management Plans. (ACTION: LAs, MAFF)
Where appropriate, include the requirements of the species when preparing or revising prescriptions for relevant agri-environment schemes. (ACTION: CCW, NE, MAFF, WOAD)
Site safeguard and management
Where possible, ensure that all occupied and nearby potential habitat is appropriately managed by 2008, for example through agri-environment scheme management agreements. (ACTION: CCW, NE, MAFF, WOAD)
Ensure that the habitat requirements of Osmia xanthomelana are taken into account in relevant coastal protection and development policies, plans and proposals. (ACTION: CCW, NE, LAs)
Ensure that this species is included in site management documents for any relevant SSSIs. (ACTION: CCW, NE)
Consider notifying sites supporting viable populations of Osmia xanthomelana as SSSIs, where this is necessary to secure their long-term protection and appropriate management. (ACTION: CCW, NE)
Species management and protection
If necessary to maintain five viable populations, undertake habitat restoration and/or re-introductions at suitable former or potential sites. (ACTION: CCW, NE)
Advisory
Advise landowners and managers of the presence of the species and the importance of beneficial management for its conservation. (ACTION: CCW, NE)
Future Research and Monitoring
Undertake further surveys to determine the status of the bee by 2005. (ACTION: CCW, NE)
Promote ecological research to establish the habitat requirements of this species, the factors limiting breeding success at existing sites, its dispersal ability, and appropriate reintroduction methods. (ACTION: CCW, NE)
Establish a regular monitoring programme for the species. (ACTION: CCW, NE)
Pass information gathered during survey and monitoring of this species to a central database for incorporation into national and international databases. (ACTION: CCW, NE)
Communications and Publicity
Promote opportunities for the appreciation of this species and the conservation issues associated with its habitat. This should be achieved through articles within appropriate journals, as well as by a publicity leaflet. (ACTION: CCW, NE)
Links with other action plans
None given.
Local implementation
The following LBAPs are working on Osmia xanthomelana:
Publication details
Originally published in: UK Biodiversity Group Tranche 2 Action Plans - Volume IV: Invertebrates (March 1999, Tranche 2, Vol IV, p273)