Clarke Webb Ecology Limited
ECOLOGICAL SURVEYORS & CONSULTANTS
Trevethin School Chapel
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Bat Survey and Mitigation Strategy
Survey dates: 3rd March 2007 – 16th November 2012
Report prepared by: Dr Peter Webb MIEEM
Clarke Webb Ecology Ltd Company No 4339567
111 Stackpool Road Bristol BS3 1NX
Tel: 0117 9662348 Email:
Trevethin School Chapel
1 Background
1.1 This report relates to the proposed redevelopment of a site previously occupied by Trevethin School
1.2 Detailed bat survey (including a thorough daytime inspection and a series of evening emergence and sunrise bat surveys) of the site was carries out in summer 2007 at which time evidence was found for the presence of various roosts within the main building complex or the chapel as summarised in the table below:
Building / Location / Species / EvidenceMain school building complex / Three roof voids / Brown long-eared / Isolated or light scatterings of what appeared to all be old droppings. No bats appeared to be in residence at the time of survey
Main school building complex / One roof void / ? / Substantial piles of old, disintegrating droppings. No bats appeared to be in residence at the time of survey
Main school building complex / Crevice in gable end / Pipistrellus sp / Several droppings noted stuck to the gable end wall. No bats appeared to be in residence at the time of survey
Chapel / Gap in soffit on western gable / Common pipistrelle / At least 6 individuals noted emerging and/or entering during evening emergence/sunrise surveys
Chapel / Roof void / Brown long-eared / Several small accumulations of droppings on floor. A single bat was noted apparently emerging from the building on a single occasion during an evening emergence survey
Chapel / Cellar / Lesser horseshoe / Single torpid bat present in March
1.3 Since 2007 all buildings present on the site have been demolished apart from the chapel which still remains, though is unoccupied and becoming derelict.
1.4 The buildings were demolished with the consent of the Local Planning Authority and under an EPS (European Protected Species) licence from the Welsh Assembly Government relating to the impact of the demolition on the bat roosts present.
1.5 In compensation for loss of the bat roosts within the main school building complex the chapel was to be retained and it suitability for use by bats improved, most notably by:
i. creating new flying access into the roof space;
ii. replacing the corrugated walls of the cellar with block walls to include a single, grilled flying access point for bats.
1.6 A new scheme for residential redevelopment of the site is now proposed. This new scheme will require removal of the chapel and hence the loss of the bat roosts within it and any compensatory measures previously incorporated into it.
1.7 This document details evidence for current and historic use of the chapel by bats and measures that will be taken to mitigate against any impact of the new scheme upon bats. Given that the proposals will impact upon bat roosts a further EPS license will be required from WAG prior to demolishing the chapel. To ensure consistency this document has therefore been produced in a format suitable for subsequent submission to the WAG in support of such a licence application.
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Trevethin School Chapel
Document 1 – Background and Supporting Information
A Executive Summary
i. An application is being submitted for planning consent for residential redevelopment of what was previously Trevethin Community School.
ii. Most building previously present on the site have already been demolished. There remains a large Chapel, unoccupied and becoming derelict. The Chapel houses an extant lesser horseshoe bat satellite roost and is known to have also been used (at least historically) by brown long-eared and common pipistrelle bats.
iii. The proposed redevelopment includes demolition of the Chapel and hence permanent loss of any roosts within it.
iv. While loss of the Chapel is unlikely to have a significant impact on local populations of brown long-eared or common pipistrelle bats there could be a significant adverse impact on lesser horseshoe bats.
B Introduction
B.1 Background to activity/development
i. An application is being submitted for planning consent for residential redevelopment of what was previously Trevethin Community School.
ii. The proposals include demolition of the openly remaining building on the site, the Chapel. This building is known to be used (either historically or recently) as a roost by several species of bat.
B.2 Full details of proposed works on site that are to be covered by the licence
i. Survey has established the presence or likely presence within the Chapel of the following bat roosts:
a) an active lesser horseshoe bat satellite roost within the roof void;
b) a minor/occasional lesser horseshoe bat day/night roost within the cellar;
c) a, possibly no longer extant, common pipistrelle bat summer roost within the soffit on the western gable;
d) a, possibly no longer extant, brown long-eared bat summer roost within the roof void.
ii. The works will involve the demolition of the Chapel and hence permanent loss of all of the above roosts;
iii. The licence will therefore cover:
a) possible disturbance of small numbers of adult lesser horseshoe, common pipistrelle or brown long-eared bats should they be present within the building during works;
b) permanent destruction of the above roosts.
C Survey and site assessment
C.1 Pre-existing information on bat species at the survey site
None known.
C.2 Status of species
Lesser horseshoe, brown long-eared and common pipistrelle bats are all relatively common regionally, where habitat is suitable. The site backs onto a wooded hillside that is relatively well-linked to other local woodland blocs and the nearby Afon River Valley. While land to the south is urbanised, land to the north is relatively rural. The locality therefore appears currently suitable for use by all three of the above species. Notwithstanding the above, we understand that:
i. there is a lesser horseshoe bat maternity roost in Pontypool (and within 500 m of the site) and a further known lesser horseshoe bat roost in St Lukes Church, Pontnewydd;
ii. the nearby lesser horseshoe maternity roost is vulnerable and susceptible to vandalism;
iii. there are also local records of soprano and common pipistrelle bats and of noctule bat from the nearby Pontypool Leisure Centre and Leisler’s bat from the nearby Penygarn School.
C.3 Objectives of the survey
The intent of the survey was to establish any use of the Chapel by bats with sufficient confidence to enable an appropriate mitigation/compensation strategy to be drawn up for any possible adverse impact of the proposed works on local bat populations.
C.4 Scaled plans/maps of survey area
C.4a Site location plan
Based on a reproduction from the Ordnance Survey under licence no: 100041216
C.4b Existing site plan.
C.5 Site/habitat description
The Chapel is unoccupied and has been subjected to significant vandalism. Most of the windows have been broken and are now boarded up or protected with wire meshing though at the time of the most recent survey (November 2012) some of this boarding had been pulled off.
The Chapel is rendered with a pitched roof fitted with slates with timber plank sarking below. The main part of the building is single-storey though of at least two-storey height. There are small, single-storey, flat-roofed extensions on both the northwest and southwest corners. The ridge is tiled. There is a soffit on the west gable, but none on the east gable and no fascias along the eaves. Window frames are sound and secure. Various roof slates have slipped or been broken. The ridge appears generally secure. There is small bell tower c half way along the ridge and that contains four louvered windows though all are sealed behind by layers of roofing felt or similar. A single roof space is present that extends across the whole of the main part of the building and is around 3 m in height at the ridge. The bell towered is contiguous with the roof void. A further, louvered window in the east gable leads directly into the roof space though would be awkward flying access for bats.
Though most of the openings have been boarded up or otherwise secured with wire mesh, one window (approximately 5 m above the ground on the west gable) has been left open and unobstructed so as to allow flying access for bats onto the ground floor. Holes have also been punched in the overlying ceiling so as to allow bats flying access into the roof space. Our understanding is that prior to 2007, no such flying access was available.
The Chapel sits on the western edge of what was Trevethin Community School. Land to the west drops steeply a way and is wooded. The west gable of the Chapel lies within this woodland and as the land drops, the gable extends several metres below ground floor level. A small cellar (around 2 m deep, 2 m high and extending the width of the entire building – including the flat-roofed extensions) is present along the bottom of the west gable. We understand that the west wall of this cellar was previously (in 2007) primarily constructed of tin but that under the previous EPS bat license this wall was subsequently rebuilt in block-work with a single, grilled entrance (to allow flying access for bats). Part of the block wall has since collapsed (see photographs) and the cellar is now relatively exposed and draughty.
Other than the Chapel all buildings that were previously present have been demolished since 2007. The remainder of the site (ie to the north, south and east of the Chapel) is now derelict land occupied primarily by rubble and invasive vegetation. Land to the west of the site slopes down into the Afon River Valley. This slope (at least where adjacent to the site) is covered in broad-leaved woodland which extends some 200m down to the river and curves around to the north where is links with further woodland blocks and more open countryside.
Photographs.
P1. The Chapel as viewed from the southeast. Note the P2. The Chapel as viewed from the northwest. Note the
derelict land to the fore and the woodland to the rear. collapsed block-work at the bottom of the gable end wall
and that leads into the small cellar beyond. The grilled
window above includes a substantial opening that allows
flying access for bats into the ground floor.
P3. One of the larger accumulations of older droppings P4. One of the loose accumulations (on the plywood) of
within the roof space (mainly beyond the metal tie). more recent lesser horseshoe bat droppings within the roof
space.
C.6 Field survey(s)
All survey was carried out or led by the holder of a Countryside Council for Wales bat survey licence.
Daytime survey
The chapel was searched, inside and out, by day for any evidence of use by bats on the dates given in the table below. Surveys included inspections of the roof void (as far as was deemed safe to do so by the surveyor) and the cellar.
Date / Lead surveyor / Notes1-2nd March 2007 / Leyton Williams-Davies
23-24th July 2007 / Leyton Williams-Davies
11th August 2010 / Capita Symonds / Roof space not fully accessed
11th May 2011 / Hawkeswood Ecology Ltd / Roof space not accessed
16th November 2012 / Peter Webb / Roof space fully accessed
Evening emergence and sunrise survey 2007
A series of five evening emergence and 2 sunrise bat surveys were carried out on the wider site (covering all buildings, including the Chapel, present at that time) between the 22nd June and the 17th August 2007. A single surveyor was present for each sunrise survey and between 2 and 4 surveyor for each evening emergence survey. All survey was carried out or led by Leyton Williams-Davies.
Evening emergence survey 2010
The building was watched for bats emerging from it over dusk on the 11th August 2010 as part of the agreed monitoring in relation to the previous EPS licence. Survey was carried out by Capita Symonds employees.
Evening emergence and sunrise survey 2011
The building was watched for bats emerging from it over dusk on the 15th June 2011 and entering over dawn on the 26th July 2011 as part of the agreed monitoring in relation to the previous EPS licence. Survey was carried out by Capita Symonds employees.
C.7 Survey results
All evening emergence and sunrise surveys were carried out under fair weather conditions.
The following evidence was found for use of the Chapel by bats:
Species / Date / No. / Location / EvidenceLesser horseshoe / 02.03.07 / 1 / Cellar / Noted hanging, torpid, from ceiling.
11.08.10 / ? / Roof void / Confirmed as present within roof void though a thorough count was not carried out.
11.08.10 / ? / Cellar / Droppings noted on cellar floor. No bats present.
11.08.10 / 6+ / Roof void / Seen to emerge from the designated roost entrance in the western gable end at dusk. Assumed to all have originated from within the roof void.
11.05.11 / ? / General / The presence of droppings on the ground floor and at least one individual within the building were noted.
15.06.11 / 6+ / Roof void / Seen to emerge from the designated roost entrance in the western gable end at dusk. Assumed to all have originated from within the roof void.
26.07.11 / 13+ / Roof void / Seen to enter the designated roost entrance in the western gable end at dawn. Assumed to have flown up to roost in the roof void.
16.11.12 / ? / Roof void / Several accumulations, each of several hundred droppings, on the floor. At least several hundred dropping in total with a high proportion appearing relatively recent.
? / 16.11.12 / ? / Roof void / Several thousand old, disintegrating droppings in two accumulations on floor. Species unclear.
Brown long-eared / 02.03.07 / ? / Roof space / Several small accumulations of droppings noted on the floor and a light scattering under the roof ridge.
01.08.07 / 1 / Western gable / Probably emerged from an unidentified location at dusk.
Common pipistrelle / 01.08.07 / 6 / Western gable / Seen to emerge from a gap in the soffit at dusk.
02.08.07 / 3 / Western gable / Seen to emerge from the gap in the soffit at dusk.
17.08.07 / 1 / Western gable / Seen to enter the gap in the soffit at dawn.
Notwithstanding the above we note that the exterior of the building presents relatively few crevices that appear suitable for use as roosts by bats.