5. Discussion
5.1 Habitats
The habitats within the Site and wider study area include mature woodland, hedgerows and watercourses that provide bats with excellent sheltered foraging and commuting routes through the landscape as well as roosting opportunities within mature trees. The footprint of works largely lies within areas of arable and improved grassland fields which are lower value for bats. At the northern end of the proposed route it crosses a small area of mixed plantation woodland and a new cable bridge is to be installed across the Braid Burn at the southern end of the route. These works will require vegetation removal including tree felling but the width of the works corridor is such that it is unlikely to result in the severance of commuting or foraging routes during the construction or operational phase.
5.2 Trees
5.2.1 Trees 16 and 17
During activity surveys low numbers of pipistrelle bats were active foraging and commuting in the vicinity of the trees with one Myotis bat pass also recorded near Tree 16. No roosting behaviour was observed at either tree. Following a revision to the design both trees now lie outwith 30 m of the proposed works and require no further consideration.
5.3 Structures
5.3.1 Bridge TN24
The active season survey found no evidence that bats are roosting within the railway overbridge at TN24. Bat activity during the survey was low with one pipistrelle bat active foraging in the arable field to the south of the structure location. No further survey or consideration of this structure is required.
5.4 Potential roost features (Trees and Structures)
Table 5 below outlines the recommended minimum protection zone when considering the potential for works to result in the disturbance of roosting bats due to associated levels of noise, vibration, and dust (adapted from Shawyer, 2011[1]). The final design has been produced with consideration of potential roost features to avoid wherever possible. At present all potential roost features now lie outwith 30 m of the Proposed Works as shown on Figure 7.3.2 and no further survey of these trees or structures is required. However, if there is a change to the planned works and a suitable minimum protection area cannot be maintained then further survey will be necessary and a Suitably Qualified Ecologist (SQE) must be consulted.
Table 5. Recommended protection zones for different levels of disturbance (Shawyer, 2011)
Predicted Level of Disturbance | Example Site Activities | Minimum Protection Zone |
|---|---|---|
Low | Pedestrian movement Storage of materials Artificial lighting (not directed towards potential roost feature) | 10 m |
Moderate | General building and landscaping works – laying of concrete, bricks, roofing etc. Using mechanised plant | 15 m |
High | Heavy construction works – ground levelling, pile driving, use of compacting roller etc. using heavy plant | 30 m |
5.5 Birds
It is noted that habitats within the Site also provide numerous nesting opportunities for birds. If works are undertaken in the nesting season from March to August, inclusive, these activities could result in the loss of one or more active nests, which would constitute an offence under the Wildlife and Countryside Act (WCA) 1981 (as amended).
To ensure compliance with the WCA 1981 (as amended), works should be completed outside of the nesting season. If this is not possible, a SQE should search works areas for evidence of nesting birds within 48 hours of works commencing. Should a nest be recorded, a suitable protection zone must be put in place until the young have successfully fledged the nest.
5.6 Use of Appropriate Lighting
Artificial lighting can often impact the foraging and commuting behaviour of nocturnal mammals, notably bats. Consequently, it is advised that if task lighting is required during works, then it should be directed to where it is needed and light spillage (whether direct and/or in-direct) should be avoided, particularly within the vicinity of the confirmed roost locations and woodland edge habitat (BCT/ILP, 2018). Further guidance is available from the EUROBATS Secretariat (Voigt et al., 2018). The design of permanent lighting within the development should also take the above into account to avoid potential long-term impacts on roosting, foraging and commuting behaviour of bats within the Site.
5.7 Repeat Surveys
The survey data in the present report are considered valid for 12 months. As works will not commence before September 2022, it is recommended that an update survey is undertaken, as per the methods section of this report, to ensure there has been no significant change to the baseline outlined within this report.
- Compliance with Legislation
Compliance with Legislation
Fulfilment of the recommendations outlined above will ensure compliance with the relevant nature conservation legislation outlined in Section 2.1.
7. References
BCT/ILP (2018). Bats and artificial lighting in the UK. Guidance Note 08/18. Bats and the Built Environment series. Bat Conservation Trust and Institute of Lighting Professionals. Available online at: https://cdn.bats.org.uk/pdf/Resources/ilp-guidance-note-8-bats-and-artificial-lighting-compressed.pdf?mtime=20181113114229&focal=none
Bat Tree Habitat Key (2018). Bat Roosts in Trees: A Guide to the Identification and Assessment for Tree-Care and Ecology Professionals. Pelagic Publishing.
CIEEM (2013). Competencies for Species Survey: Bats. Available online at https://cieem.net/wp-content/uploads/2019/02/CSS-BATS-April-2013.pdf (accessed March 2022).
Collins J (ed.) (2016). Bat Surveys for Professional Ecologists: Good Practice Guidelines, Third Edition. The Bat Conservation Trust, London.
ITPEnergised (2022). Berwick Bank EIA, Ecology Chapter, Technical Appendix 7.1, Preliminary Ecological Appraisal.
Mitchell-Jones AJ (2004). Bat Mitigation Guidelines. English Nature, Peterborough
Mitchell-Jones AJ and McLeish AP (2004). Bat Workers’ Manual (3rd Edition). Joint Nature Conservation Committee, Peterborough
Shawyer CR (2011). Barn owl Tyto alba Survey Methodology and Techniques for use in Ecological Assessment. Developing Best Practice in Survey and Reporting. IEEM, Winchester.
TWIC (2021). Protected and Notable Species Records. Received January 2021.
Voigt CC, Azam C, Dekker J, Ferguson J, Fritze M, Gazaryan S, Hölker F, Jones G, Leader N, Lewanzik D, Limpens HJGA, Mathews F, Rydell J, Schofield H, Spoelstra K and Zagmajster M (2018). Guidelines for consideration of bats in lighting projects. EUROBATS Publication Series No. 8. ENEP/EUROBATS Secretariat, Bonn, Germany, 62 pp. Available online at: https://cdn.bats.org.uk/pdf/Resources/EUROBATSguidelines8_lightpollution.pdf?mtime=20181113114256
Figures
Figure 7.3.1 – Location Plan
Figure 7.3.2 - PRA Results
Annexes
Annex A – Target Notes
Table A1. Trees with Potential Roost Features
Target Note | Grid Reference (X/Y) | Summer Roost Potential | Winter Roost Potential | Description |
|---|---|---|---|---|
1 | NT 73770 73284 | High | Low |
Sessile oak with observable broken limbs and cracks along branches approximately 30 m above ground level. Features could provide roosting potential for multiple bats and surrounding habitat is considered to have High suitability for use by bats. If tree to be impacted recommend climb and inspect survey to fully assess features for evidence of and/or potential for, roosting bats. |
2 | NT 73884 73281 | Moderate | Negligible |
Ash tree with visible crack in trunk approximately 4m above ground level that could be utilised by multiple bats. Surrounding habitat is considered to have Moderate suitability for bats. If tree to be impacted recommend climb and inspect survey to fully assess features for evidence of and/or potential for, roosting bats. |
3 | NT 73807 73306 | Low | Negligible |
Ash with ivy cover and holes in trunk that may provide roosting opportunities for individual bats. Tree is approximately 10 m in height. If tree to be impacted recommend climb and inspect survey to fully assess features for evidence of and/or potential for, roosting bats. Surrounding habitat is considered to have Moderate suitability for use by bats. |
4 | NT 73724 73304 | Moderate | Negligible |
Ash with two large branch breaks and splintered wood with potential for use by multiple bats. Habitat in close proximity considered to be Moderate suitability for use by bats. Feature height from ground c.10m. If tree to be impacted recommend climb and inspect survey to fully assess features for evidence of and/or potential for, roosting bats. |
5 | NT 74368 72362 | Moderate | Low |
Ash with two holes in trunk that could be utilised by individual bats. If tree to be impacted recommend climb and inspect survey to fully assess features for evidence of and/or potential for, roosting bats. |
6 | NT 74135 72383 | High | Moderate |
Sessile oak with 2 m long crack in main stem that could be used by multiple bats over summer and winter. Habitat is also considered to be High suitability for use by bats. If tree to be impacted recommend climb and inspect survey to fully assess features for evidence of and/or potential for, roosting bats. |
7 | NT 72246 74719 | Low | Negligible |
Large sycamore with broken trunk that has small cracks running down main stem that could be utilised by individual bats. Area considered to be low potential for bats due to the poor connectivity of copse to wider landscape. If tree to be impacted recommend climb and inspect survey to fully assess features for evidence of and/or potential for, roosting bats. |
8 | NT 73925 72351 | Low | Negligible |
Sessile oak with broken limb showing cracks that could be accessed by individual bats. Feature located c.5 m above ground level. If tree to be impacted recommend climb and inspect survey to fully assess features for evidence of and/or potential for, roosting bats. |
9 | NT 73930 72773 | Low | Negligible |
Sycamore with large amount of raised bark that could be utilised by individual bats. Habitat considered Moderate suitability for use by bats. If tree to be impacted recommend climb and inspect survey to fully assess features for evidence of and/or potential for, roosting bats. |
10 | NT 74292 72750 | Mod | Low |
Pedunculate oak with broken limbs with cracks that could be utilised by individual bats. Surrounding habitat considered to have Moderate suitability for use by bats. If tree to be impacted recommend climb and inspect survey to fully assess features for evidence of and/or potential for, roosting bats. |
11 | NT 74725 73273 | Low | Negligible |
Ash with large tear-out exposing hole in main stem that could be utilised by multiple bats, approximately 5 m above ground level. Surrounding habitat considered to have Moderate suitability for bat use including a small burn. If tree to be impacted recommend climb and inspect survey to fully assess features for evidence of and/or potential for, roosting bats. |
12 | NT 74725 73273 | Moderate | Low |
Ash with large gaping cavities up trunk that could be accessed by multiple bats. Features observed to be c.8 m from ground. Further active season surveys recommended if tree to be impacted. |
13 | NT 72246 74719 | High | Low |
Kent bat boxes affixed to north side of semi-mature ash. Difficult to reach with ladder so would need climbed if they are to be inspected. |
14 | NT 73702 75426 | High | Low |
Kent bat boxes x2 attached to juvenile ash. Tree tag 0619. Can be reached by ladder to inspect. |
15 | NT 73674 75413 | High | Low |
Kent bat box and bird box. Easy to reach with ladder to inspect. |
16 | NT 73646 75399 | Moderate | Negligible |
Split down trunk from broken limb of ash measuring 50 cm in height, suitable for use by individual bats. Located in good bat habitat of broadleaved woodland. Active season surveys and/or inspect using ladder to access. |
17 | NT 73923 74072 | Moderate | Negligible |
Large ash located on south side of Thornton burn with features that could be used by individual bats including branch cracks and lifted bark in good bat habitat. Recommend active season surveys and/or climb and inspect. |
18 | NT 74228 72431 | Moderate | Negligible |
Large ash with woodpecker damage and lifted bark in good habitat for bats. Can be checked by tree climbers. |
19 | NT 73473 73178 | High | Low |
Sessile oak with large fracture 2m long down trunk and multiple broken branches in good bay foraging habitat. Can be checked by tree climbers |
Table A2. Structures with Potential Roost Features
Target Note | Grid Reference (X/Y) | Summer Roost Potential | Winter Roost Potential | Description |
|---|---|---|---|---|
20 | NT 74370 74152 | Moderate | Moderate |
Railway underbridge passing over Thornton Burn that has visible gaps in brickwork and cracks in barrel that can be accessed by multiple bats. Potential for use as both a summer and winter roost site. |
21 | NT 73855 75399 | High | High |
Old lime kilns with high bat roost potential due to gaps in brickwork on sides and roof of kiln with deep crevices providing access to multiple bats. |
22 | NT 73780 75398 | Low | Low |
Public toilets with slate roof tiles. The building is considered to have Moderate bat roost potential for use as a summer roost, with multiple gaps under tiles that could be utilised by low numbers of bats (1-2 bats). No internal survey completed of loft space but no evidence of bat roosting activity found on walls or from crevices under the fascia of roof. |
23 | NT 75287 73519 | Moderate | Low |
Railway bridge with high bat roosting potential due to gaps in concrete and brickwork |
24 | NT 76082 72909 | Low | Low |
Rail overbridge that could not be accessed because of the live train line. Stone wingwalls, abutments and parapets. Overall stonework was in good condition with no suitable roost features evident, however as lineside access was not possible to fully inspect, a precautionary approach was adopted and the bridge is assessed as having Low bat roost potential. |
25 | NT 75835 73114 | Moderate | Low |
Small rail bridge with features including gaps between concrete overhead and gaps in connecting brickwork. |
26 | NT 72637 75449 | Moderate | Low |
|
27 | NT 72664 75429 | Negligible | Negligible |
ECML railway bridge (ECM8/098) over farm track. Stone construction. Pointing in good condition with no potential roost features identified. |
Annex B – Survey Forms
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[1] Note this reference relates to barn owl (Tyto alba) mitigation; however, the reasoning behind the size of disturbance buffers is considered applicable to bats also, and similar bat disturbance buffers have been accepted by NatureScot on other schemes.