Daubenton’s Bat is protected by law - a combination of UK legislation (Wildlife and Countryside Act 1981) and European legislation (Habitats Directive). Although it has a relatively wide spread distribution across the country, few maternity roosts are known with 10 recorded in North East Scotland. The bat is found close to water courses, where it feeds on insects and roosts in nearby trees.

Daubenton’s Bat is listed as a species of conservation concern by the Biodiversity Steering Group. The bat is threatened largely through loss of roosts and changes in riparian vegetation and water quality.

The Bat Conservation Trust has published a Conservation Action Plan for bats. The action plan presented here is based on this and relates specifically to North East Scotland. A major monitoring and recording programme also has been established to aid understanding of bat distribution and numbers.

Bridge repairs and tree surgery may damage the roosts through lack of bat awareness by contractors. One of the main objectives therefore, is to increase general awareness of bats and provide appropriate professional guidance. Guidance for estate managers also will be provided, for the effective conservation of riparian habitats.

Roosts are protected by law but there may be scope to enhance the protection of appropriate habitats. Additional roosts should be provided by erection of bat boxes.

Further monitoring and surveying will provide greater understanding of bat requirements and their effective range. The success of the action plan also will be determined by monitoring of populations.

1. CURRENT STATUS

With the exception of the Western and Northern Isles of Scotland, Daubenton’s bat is widespread throughout the British Isles, but is largely restricted to riparian and lacustrine habitats. Increases have been reported in continental Europe, which may be the result of pollution causing eutrophication of water bodies and increasing availability of prey such as chironomids, (Kokurewicz, 1995). No such increases in Daubenton’s bats have been reported in the British Isles, although in North East Scotland a small eutrophic river (the Ythan) can support as many bats as the larger oligotrophic river Dee (Racey 1998; Racey et al in press).

Listed in Schedule 5b of the Wildlife and Countryside Act 1981, Daubenton’s bat, in common with all other UK bats, is protected against intentional killing, injuring or taking, and its roosts are protected against damage, destruction or obstruction. It is also an offence to intentionally disturb any bat species, whether or not the bat is in a roost.

Additional protection (notably of feeding habitat) is provided by the (Bern) convention on the Conservation of European Wildlife and Natural Habitats, 1982. All species of European bats (except the pipistrelle) are listed in Appendix II, the Agreement on the Conservation of Bats in Europe (Bonn Convention on the Conservation of Migratory Species of Wild Animals, 1992, Appendix II), and the European Community’s Directive on the Conservation of Natural and Semi-natural habitats and of Wild Fauna and Flora, 1992 (Annex IVa).

2. ECOLOGICAL DATA

Rarely found away from riparian habitats, Daubenton’s bat forages over open water, taking insects from the water surface, or in flight in the 1 m of airspace above the water (Rydell et al 1994). It preys primarily on Diptera and Trichoptera (Swift & Racey 1983; Vaughan 1997). On rivers it shows a strong preference for smooth-flowing water with tree cover on both banks (Warren et al 1997). It typically forages over a short stretch of river, but can be found up to 5 km from the roost, and can travel much further. It also forages over canals, lakes and even quite small ponds (Swift & Racey 1983).

Roosts are found in tree holes, the stonework of bridges, and in buildings close to open water. About 60 maternity roosts are known in Britain (AL Walsh pers comm) 10 of which are in Deeside and Donside. In summer there is evidence for sexual segregation in the foraging areas with males found further upstream than females (Warren et al 1997). Known hibernation sites are primarily in caves, mines, tunnels and the stonework of bridges and probably also in trees.

3. CURRENT FACTORS AFFECTING DAUBENTON’S BAT

Continuous riparian woodland is probably most important in the vicinity of roosts. Distribution and density, particularly of maternity roosts, may be limited by the area of suitable water over which to forage.

Loss of roost sites in trees, buildings and bridges close to suitable foraging sites is probably an important limiting factor. Inappropriate management of bank-side trees and trees in nearby woodland would reduce the number of potential roost sites, primarily by the removal or excessive surgery of old trees. Inappropriate bridge maintenance has the potential for catastrophic destruction of roost sites and resident bats.

Agricultural run-off (nutrients, herbicides and pesticides) into rivers, canals and lakes will lead to changes in prey availability and loss of bank side vegetation will degrade the habitat. Inappropriate water management, such as excessive water abstraction, will lead to loss of key foraging areas.

In the short to medium term, Daubenton’s bat may be limited by pollution incidents that reduce prey availability, and by fluctuations in water levels.

4. CURRENT ACTION

All UK bat species and their roosts are protected by the Wildlife and Countryside Act (1981). The Bat Conservation Trust (BCT) and local Bat Groups assist in the enforcement of the Act by answering public enquiries and visiting roosts under potential threat. The BCT also carries out a wide range of practical conservation measures, including survey and monitoring. Many Bat Groups keep detailed records, and the BCT is working to standardise these. The government agencies hold records of roost sites. The Farming and Wildlife Advisory Group (FWAG) routinely highlight bats and bat habitat management to farmers. The Scottish Environmental Protection Agency (SEPA) promotes appropriate riparian management for bat habitat. The Joint Nature Conservancy Council (JNCC) is currently producing a guide to ‘Habitat Management for Bats’ and the production of a UK leaflet is being discussed.

The BCT has published an ‘Action Plan for the Conservation of Bats in the UK’ (Hutson 1993), reviewing progress, and suggesting where future effort might be best directed. The recent National Bat Habitat Survey (Walsh and Harris 1996 a, b) is the first to look at the abundance of bats on a national and local scale and determine habitat preferences in a major survey. This is now being followed up by a DETR-funded project which the BCT are carrying out (The National Bat Monitoring Programme – NBMP) to establish methods for the monitoring of bats in roosts, foraging areas and hibernacula. There is a specific programme for monitoring Daubenton’s bat, now entering its second year.

5. BENEFITS

Fulfilling this action plan will increase greatly our knowledge of the distribution and ecological requirements of the bat. Its effective range will be monitored and roosts will be protected. Roost habitats include fresh water and riparian woodland. Protection of these habitats, through suitable management, as well as protecting the bat, will ensure protection of river corridors and associated vegetation and animals.

Daubenton’s Bat is a species of conservation concern listed in the UK Biodiversity Action Plan. No UK action plan has been published as yet.

To provide guidance on practical management techniques designed to maintain and enhance Daubenton’s bat populations. These may be utilised by SNH and SEPA in their operational activities, as well as by other agencies and land owners. Promote use of suitable habitat and roost site management techniques.

Demonstrate the enhancement of Daubenton’s bat populations by means of appropriate monitoring. Monitoring can be carried out using ultrasound detectors, counting bat passes/unit time in predetermined areas. As roost sites are difficult to locate, counts of bats as they emerge in the evening are unlikely to be as useful as standardised bat pass counts in predetermined aquatic habitats (Warren et al 1997).

REFERENCES

HMSO (1995). Biodiversity. The UK Steering Group Report vols 1 & 2. London, HMSO.

Vaughan N (1997). A review of the diets of British bats (Chiroptera). Mammal Review 27: 77-94

This plan is based on one prepared for the Environment Agency by Drs JD Altringham, DJ Bullock, RD Warren and DA Waters.

PROPOSED ACTION REQUIRED TO MEET OBJECTIVES

ABG-Aberdeen Bat Group, ACC-Aberdeen City Council, AC-Aberdeenshire Council, AU-Aberdeen University, BCT-Bat Conservation Trust, FWAG-Farming and Wildlife Advisory Group, GET-Gordon Enterprise Trust, LA-Local Authority, LO-Landowner, NBMP-National Bat Monitoring Programme, NTS-National Trust for Scotland, SERAD-Scottish Executive Rural Affairs Department, SNH-Scottish Natural Heritage, SWT-Scottish Wildlife Trust.