APPENDIX E: 2007 ECOLOGY REPORT Contents 1 Introduction 2 Methodology 3 Results 4 Recommendations 5 References
APPENDIX E: 2007 ECOLOGY REPORT
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Surveys for Bat, Otter and Water Vole
Contents
1 Introduction
2 Methodology
2.0 Water vole
2.1 Otter
2.2 Bats
3 Results
3.0 Water vole
3.1 Otter
3.2 Bats
4 Recommendations
4.0 Otter
4.1 Water voles and bats
5 References
A82, Ba Bridge
September 2007
Produced for
Scotland TranServ
Prepared by
Toby Fisher
Senior Ecologist
93 Water Lane
Leeds
West Yorkshire
LS11 5QN
UK
T 0113 203 5600
F 0113 203 5601
Document Control Sheet
Project Title |
A82, Ba Bridge |
Report Title |
Surveys for Bat, Otter and Water Vole |
Revision |
0 |
Status |
FINAL |
Control Date |
September 2007 |
Record of Issue
Issue |
Status |
Author |
Date |
Check |
Date |
Authorised |
Date |
1 |
ISSUED |
T Fisher |
Sep 07 |
C Parkinson |
Sep 07 |
T Fisher |
Sep 07 |
|
1 Introduction
Mouchel Parkman Services Limited was commissioned by Scotland TranServ in July 2007 to undertake surveys for bats, otters and water voles at Ba Bridge on the A82. This report presents the results of these surveys and it is anticipated that this report will form an appendix to the Environmental Statement (ES) relating to improvements to this bridge.
Ba Bridge is located at National Grid Reference NN 309494 spanning River Ba as part of the A82 running broadly South-East to North-West between Tyndrum and Ballachulish.
Ba Bridge lies within Rannoch Moor Site of Special Scientific Interest (SSSI) and immediately adjacent to both Rannoch Moor Special Area of Conservation (SAC) and Rannoch Lochs Special Protection Area (SPA).
2 Methodology
Specialist surveys for water vole Arvicola terrestris covered all potentially suitable habitat within ~100m of the bridge on 11th August 2007. The survey was based on the methodology described in Strachan and Moorhouse (2006) and involved detailed searches for field signs such as droppings, latrines, feeding stations, burrows, footprints and runs.
In conjunction with the surveys for water vole, the banks of the River Ba within 100m of the bridge were subject to detailed searches for signs of otter such as spraint, feeding remains and footprints, based on the methodology described in Chanin (2003), paying particular attention to likely sprainting sites such as around the bridge.
The bridge was subject to a daytime assessment in terms of its potential to support bats on 11th August 2007. The bridge was also searched for signs of bats such as droppings, staining and bat corpses using close focussing binoculars where appropriate.
A dusk emergence survey was undertaken on 11th August (see Table 1 below) which involved two bat surveyors positioned either side of the bridge, in accordance with the methodology outlined in The Bat Mitigation Guidelines (Mitchell-Jones 2004). The surveys were undertaken during suitable weather conditions using hand-held heterodyne / frequency-division bat detectors (model: Duet Bat-Box).
Table 1: Survey conditions during bat dusk emergence survey
Date |
11th August 2007 |
Sunset time |
20:59 |
Survey time |
20:40 – 22:10 |
Weather conditions |
Dry; cloud 7/8; still; start temp ~15°C; end temp ~13°C |
3 Results
Despite a specific search, no signs of water voles were recorded. The river banks along this stretch appear to be largely unsuitable for water vole due to the rocky and stony substrate although some opportunities for burrowing appear to exist in some areas.
A fresh wet otter spraint was found on the grassy bank immediately south-west of Ba Bridge. Its location on a path which leads over the A82 suggests that otters may cross the live carriageway here. No potential holt sites were identified within 100m of the bridge.
The daytime inspection of the bridge revealed that superficially it is in generally good condition with very few cracks or crevices suitable for bat roosts.
The survey did not reveal any bat roosts within the bridge. The only bat recorded was a single common pipistrelle Pipistrellus pipistrellus recorded at 21:32 foraging briefly around the bridge. The time of this record approximately 30 minutes after sunset suggests that it was roosting fairly nearby.
4 Recommendations
If practicable, an otter ledge should be installed on the underside of the bridge to encourage safe crossing of the A82 by otters. Further guidance and design options are available in the Design Manual for Roads and Bridges Volume 10, Section 4, Part 41.
No further surveys or mitigation is considered necessary for water voles and bats.
5 References
Chanin, P. 2003. Monitoring the Otter Lutra lutra. Conserving Natura 2000 Rivers Monitoring Series No. 10. English Nature: Peterborough.
Mitchell-Jones A, J. 2004. Bat Mitigation Guidelines. English Nature, Peterborough.
Strachan, R. and Moorhouse, T. 2006. Water Vole Conservation Handbook – Second Edition. Wildlife Conservation Research Unit, Oxford University.