bat activity transect survey report - · pdf filebat activity transect survey report _____ the...

Registered in England & Wales No. 5574199 Registered Office: 225 Bailbrook Lane, Bath, Somerset BA1 7AA

__________________________________________________________________________________________

Bat Activity Transect Survey

Report __________________________________________________________________________________________

The Land next to Quakers Walk, Devizes, Wiltshire

for

Society of Merchant Venturers ________________________________________________________________________________________________________________

Summer 2014

215 London Road East,

Batheaston, Bath BA1 7NB

Phone: 01225 858 999

Mobile: 07932 143 753

Email: [email protected]

SIMECOLOGY LTD Wildlife Surveys and Ecological Consultancy

215 London Road East,

Batheaston, Bath BA1 7NB

Phone: 01225 858 999

Mobile: 07932 143 753

Email: [email protected]

BTS-191214a-V001 Report date: December 2014 SIMECOLOGY LTD

2

Document Number:

BTS-191214a-V001

Date of Issue:

19th December 2014

Issue Number and Revision Details:

1

Main Contributor:

Steve Maguire

Issued By: Approved by:

Steve Maguire Simeon Smith


3

Contents

1. Summary .......................................................... 5

2. Introduction ...................................................... 6

2.1. Brief ................................................................................ 6

2.2. Legislation ...................................................................... 6

2.3. Survey details ................................................................ 6

2.4. Site Details ..................................................................... 7

3. Methodology .................................................... 8

4. Results ............................................................. 9

5. Interpretation of Results .................................. 11

6. Recommendations........................................... 12

6.1. Retention/planting of boundary features ..................... 12

6.2. Planting of standards .................................................... 12

6.3. Careful consideration of lighting within all phases of

development .................................................................. 13

6.4. Artificial bat roosts (enhancements) ............................ 13

7. Survey Limitations ........................................... 13

8. References ....................................................... 15

9. Figure 1: Survey area & transect route ........... 16

10. Figure 2: Graph of bat activity ......................... 17

11. Figure 3: Aerial image of site ........................... 18


4

12. Figure 4: Bat Distribution ................................ 19

13. Appendices: Legislative context and statutory

designations .................................................... 21

i. Legislative context ......................................................... 21


5

1. Summary Simecology Ltd was commissioned by Smith’s Gore, on behalf of the Society of

Merchant Venturers, to carry out three bat detector transect activity surveys in the

summer of 2014 as an update to the original surveys carried out in summer

2009.

Three bat detector transect surveys were undertaken on the evenings of 11th

June, 29th July and 31st August 2014. These were carried out by experienced bat

surveyor, Simeon Smith (NE: 20131443).

The surveys were carried out under optimal conditions following the standard

methodology (BCT 2012).

The following species were recorded using the site (in decreasing order of total

number of passes recorded); Common pipistrelle Pipistrellus pipistrellus, Serotine

Eptesicus serotinus, Soprano pipistrelle Pipistrellus pygmaeus, Myotis bats Myotis

spp., Lesser horseshoe Rhinolophus hipposideros, Brown long-eared Plecotus

auritus and Noctule Nyctalus noctule.

Common pipistrelle bats accounted for approximately 68% of all bat passes

recorded.

The majority of bat activity was recorded along the tree line of Quakers Walk itself.

The rare Lesser horseshoe bat was recorded utilising the site which would

suggest the habitat at this point (along QW) is of sufficient quality, and the light

levels are of a low enough level, to support this light shy species.

A series of measures have been recommended and will be given in greater detail

in the subsequent Ecological Method Statement.

The following features should be included:

o Bat and bird boxes on some/all of the dwellings as an enhancement

o Significant boundary features such as trees and hedgerows should be

retained where possible, with new mixed species native hedgerows

planted where appropriate.

o Common lime trees should be planted along the east and south facing

boundaries to provide opportunities for bats (and other wildlife).

o A sensitive lighting strategy should be put in place, especially along the

western boundary (35m buffer zone).


6

2. Introduction

2.1. Brief

Simecology Ltd was commissioned by Smith’s Gore, on behalf of the Society of Merchant

Venturers, to carry out three bat detector transect activity surveys in the summer of 2014

as an update to the original surveys carried out in summer 2009. These original surveys

were carried out following the recommendations of an Extended Phase One habitat

survey carried out in May 2009 by Simecology Ltd:

“It will be necessary to conduct a minimum of three bat activity surveys under

appropriate atmospheric conditions at appropriate times of the year predominantly

along boundaries B1 and B2 [the tree line of Quakers Walk] and to a lesser extent along

boundaries B4 and B5 [the northern end of the eastern site boundary]. These surveys

both will help inform any potential negative impacts a development of this site may have

upon local bat populations and help guide any necessary mitigation measures.”

2.2. Legislation All species of bat and their breeding sites or resting places (roosts) are protected under

Regulation 41 of The Conservation of Habitats and Species Regulations 2010 and

section 9 of the Wildlife and Countryside Act 1981 (as amended).

It is an offence for anyone to intentionally kill, injure or handle a bat, to possess a bat

(whether live or dead), disturb a roosting bat, or sell or offer a bat for sale without a

licence. It is also an offence to damage, destroy or obstruct access to any place used by

bats for shelter, whether they are present or not.

2.3. Survey details A route was chosen so as to achieve the greatest coverage of features with minimal

overlap (to avoid false peaks in activity). Considering both the current state of the site,

and the nature of the previous surveys, it was decided that three transects carried out


7

across the 2014 survey season should provide sufficient data to assess how bats utilise

the site.

The following table shows the start/finish times, sunset times and weather conditions for

each survey event.

12th June 29th July 31st August

Start Finish Start Finish Start Finish

Time 21.24 00.24 21.00 00.00 19.57 22.46

Temp (oC) 20 15 20.8 19 16 14

Cloud

(Oktas) 0 1 7 8 0 0

Wind (Bft) 1 0-1 1 1 0 0

Rainfall 0 0 0 0 0 0

Sunset

time 21.24 21.00 19.57

2.4. Site Details

The site consists of a large arable field which has been recently cultivated. There is a

recently completed residential development to the north.

Situated on level ground with a gentle south westerly aspect the site lies on the northern

edge of Devizes town. The surrounding landscape is predominantly one of residential

properties to the south, amenity land (sports pitches) to the east and south-east, with

arable farmland and an associated hedgerow network to the north and west. An area of

allotment gardens, lying on the northern side of the Kennet and Avon Canal, are present

immediately south of the site.

The Kennet and Avon canal lies 100m to the south of the site and a small west-flowing

stream rises amidst dense woodland approximately 150 m west of the site boundary.

On the western edge of the site, the boundary is formed by a line of mature planted

deciduous trees with some younger planted deciduous trees and small numbers of self-

sown scrub species. This line of trees forms the eastern edge of the Quaker’s Walk path

and is mirrored by a very similar feature on the western side of the path. The tall mature

trees here are a significant landscape feature.


8

The eastern boundaries of the site consist mostly of post and rail fencing with young

planted deciduous trees on the outside of the fences (i.e. not within the site); rank

grasses and tall herb vegetation are associated with these fence lines. On the southern

edge there is a diffuse boundary with the allotment gardens; rank grasses and tall herbs

predominate here but there are some young planted trees along the western half of this

boundary. A concrete post with wire mesh fence forms the western fifth of this southern

boundary.

3. Methodology Three bat detector transect surveys were undertaken on the evenings of 11th June, 29th

July and 31st August 2014. These were carried out by experienced bat surveyor, Simeon

Smith (NE: 20131443). The visits consisted of the surveyor walking a set route using a

broadband bat detector (with in-built recording device) to record bat echolocations as

‘bat passes’ and to note the bats’ behaviour. As a bat species cannot always be reliably

identified using only a social call, social calls are recorded and documented during the

survey but are not presented in the final data as representing a ‘bat pass’.

Independent ‘bat passes’ are recorded when one minute or more elapses between

periods of echolocation (a bat pass within the same minute is assumed to emanate from

the same individual, unless more than one bat is seen in the field, more than one

species is confirmed from the recordings or two bats (overlapping calls) are confirmed

from the recordings).

Visual conditions during surveys do not always render it possible to determine whether

independent bat passes from the same species are emitted from one bat which is

circling the area (whilst travelling sufficient distance to remain away from the bat

detector for at least one minute), or from different bats. Thus whilst bat passes are a

useful tool in comparing activity between similar sites, it should be understood that they

provide only a relative, rather than an absolute, index.

Bat detector transect activity surveys are carried out in accordance with the standard

methodology (Bat Conservation Trust, 2012). Transects are designed so that they can be

completed at least once within three hours on foot at a steady pace. The route is chosen


9

so that all structures and areas affected by the proposed development or works, which

are of potential importance to bats (for example foraging and commuting areas), are

surveyed. Thus on occasions it may be necessary to survey outside the survey site

boundaries, for example if lighting is anticipated to overspill onto other areas or if a

designated site is expected to be affected. The level of survey effort (in terms of

frequency or repetition and number of surveyors) is determined by several factors,

including: the area of the site and the potential value of its habitats for bats; the regional

location of the site; the quality or designation of adjacent habitats; the sites’ connectivity

with adjacent habitats; and the species of bat known in the area (in this case the

previous survey effort at the site was also a deciding factor). Point counts, where the

surveyor remains stationary for five minutes, are chosen strategically along the transect

route to incorporate potentially good bat foraging habitats with areas where commuting

bats are likely to be detected. Figure 1 displays the transect route, directions and the

location of all point count stops.

Bat detection equipment used was an Elekon Batlogger with real time recording. All calls

were recorded onto an SD card in the Batlogger. The echolocation recordings were

subsequently analysed using BatSound (version 4.14) software according to the

parameters and summary statistics on bat echolocation calls given by Russ (1999,

2012) and Parsons and Jones (2000).

4. Results A visual comparison of the results for each species has been given in the chart in Figure

2. A series of images illustrating the general distribution of bats during each surveys

event is given in Figure 4.

Bats were recorded during all three of the survey events (June, July and August) and

showed relatively consistent levels of activity throughout. At least seven species of bat

were recorded using the site for foraging, feeding, socialising and commuting. In

decreasing order of total number of passes recorded, these species are:

Common pipistrelle Pipistrellus pipistrellus

Serotine Eptesicus serotinus


10

Soprano pipistrelle Pipistrellus pygmaeus

Myotis bats Myotis spp.

Lesser horseshoe Rhinolophus hipposideros

Brown long-eared Plecotus auritus.

Noctule Nyctalus noctula

N.B It is often not possible to identify Myotis bats to species level as there is significant

overlap in the calls of bats in this genus. Also, although it is similarly difficult to

determine whether the long-eared bat was in fact a Brown long-eared, and not the much

rarer Grey long-eared, in this instance the site does not fall within the current range of

the Grey long-eared bat and as such the long-eared bat recorded is assumed to be of the

Brown long-eared variety.

Of all the bats recorded on this site the most commonly recorded species was the

Common pipistrelle having 68.37% of the total number of passes (67 passes out of a

total of 98). Serotine and Soprano pipistrelle were next with 14.29% and 10.2%

respectively. This was followed by the Myotis sp. bats with approximately 2% and the

Brown long-eared, Lesser horseshoe and Noctule bats all with around 1%.

Of the 67 total passes by Common pipistrelle bats, 86.57% was foraging behaviour and

13.43% was of commuting. The other species recorded tended to show higher levels of

foraging activity as well. Of the total passes recorded by all bats, 78.57% was of foraging

behaviour and 21.43% of commuting.

Figure 2 illustrates the relative activity of each of the recorded species. The mean

number of bat passes heard per survey was 32.3 passes. This equates to approximately

0.19 bat passes per minute (approx. average survey time – 2 hrs 50 mins), although

note that since a bat pass within the same minute is assumed to emanate from the

same individual, the actual number of pass rates would be higher than this value.

Geographically, the arrangement of activity across the site tended to favour the wooded

tree-line and scrubby margins along Quakers Walk itself with the majority of commuting

and foraging taking place along here (see Figure 4). A smaller proportion of the activity


11

was recorded around the eastern side of the site (Point counts 4, 5, 6 & 7); however the

majority of this was foraging activity of common pipistrelle. Almost all of the Common

pipistrelle, Soprano pipistrelle, Serotine and Myotis activity was recorded around the

Quakers Walk tree line. The single Brown long-eared bat was recorded at PC4, the Lesser

horseshoe just north of PC8 and the Noctule at PC6.

5. Interpretation of Results Of all the activity recorded it is significant, and not surprising, to find that the most

frequently recorded species was that of Common pipistrelle with the most well used area

being the line of mature trees along Quakers Walk itself (see Figure 4). Other more

common species such as Soprano pipistrelle and Serotine were recorded but in far fewer

number than the Common pipistrelle, being around a fifth of the Common pipistrelle’s

total passes for each of these species.

It is unsurprising that the highest proportion of the activity observed at the site was of

Common pipistrelle, it being the most common and widespread species in the British

Isles, however; the overall distribution of activity and the number of species recorded

was significant. Rarer species such as Lesser horseshoe could indicate that the habitat

quality, at least along Quakers Walk itself, is of a high enough standard to support this

species (Figure 4 image A). This would also suggest that light levels along Quakers Walk

must be sufficiently low enough to support this light-shy species.

Overall the site does provide commuting and foraging for at least seven species of bat, a

relatively high number considering the size of the site and the relatively average overall

quality of the habitat. It should however be noted that the majority of the site has

relatively low habitat value (for bats) but that the line of mature trees and scrubby

understory along Quakers Walk on the western edge provides excellent habitat features

for bats, with rare species such as Barbastelle and Greater Horseshoe having been

recorded along here in the past.

To allow the site to continue to provide foraging and commuting opportunities for bats

once the development is complete it will be necessary to retain and, where possible,


12

enhance the existing features. The high quality of the habitat along Quakers Walk should

be safeguarded during the development with a suitable buffer between it and the

houses. The other boundary features towards the eastern side of the site should be

strengthened to provide increased connectivity as the change of use from agricultural to

residential will likely have a negative impact on whether bats continue to utilise the site.

There is opportunity here to not only retain and strengthen the existing features but to

enhance and expand the bat potential through implementation of a sensitive and

considerate landscaping plan and a well designed lighting strategy.

6. Recommendations This section is a summary of the various recommendations made in relation to bat

activity on the site. A more detailed strategy will be devised and issued as an Ecological

Method Statement which will provide specific measures to ensure the continued

provision of features for bats, and other wildlife, across the site following completion of

the proposed development.

6.1. Retention/planting of boundary features The Quakers Walk tree line (consisting mostly of mature Common Lime) will be retained

as it currently exists. Other significant standard trees and hedgerows should be retained

where possible to continue to provide opportunities for bats, and other wildlife, on the

site. New boundary features (such as mixed native species hedgerows) should be

included in the landscaping strategy of the new development.

6.2. Planting of standards The southern and eastern facing boundaries of the site should be planted with standard

trees to match the tree line along Quakers Walk. This will ensure that any

foraging/feeding opportunities which will inevitably be lost due to the development will

be compensated for via inclusion of this new connecting feature. Common lime should

be used to match, and expand, the existing habitat along QW.


13

6.3. Careful consideration of lighting within all phases

of development Bats are nocturnal creatures and as such lighting should be restricted in certain areas to

avoid potential disturbance due to light pollution. The western boundary of the

development (i.e. the built element next to the 35m buffer zone) should have limited or

(preferably) no lighting installed. If lighting is required then it should be low intensity, low

level lighting of either bollard type or, if wall mounted, should be fitted with appropriate

hoods or cowls to ensure no upward light spill. This section will have no vehicular traffic

and lighting would only be required for pedestrian access. This strip along the Quakers

Walk tree line should be maintained as a dark corridor, which will benefit not only bats

but all wildlife.

Lighting products now exist which can reduce the impact to wildlife and these should be

utilised in these areas. Lighting should be towards the red (warm) end of the spectrum

with negligible UV levels, such as the Phillips ClearField lighting technologies developed

in The Netherlands.

6.4. Artificial bat roosts (enhancements) Where possible, opportunities for wildlife should be enhanced across the site. Bat boxes

of an appropriate design should be incorporated into a number of dwellings in the

proposed development. Internally mounted bat tubes and soffit boxes could all be

utilised providing a range of roosting features across the site. A variety of bird nest boxes

could also be included to further enhance opportunities for birds, which could have been

impacted by the loss of habitat at the site following completion of the proposed works.

7. Survey Limitations These surveys give an index of the intensity with which bats use a site. They are not able

to provide absolute measures of the numbers of bats present. It is possible that

additional bat species use the site, but were not present on the nights of the surveys. In

particular, surveying in the spring and earlier summer, when bats first emerge from

hibernation and are making their way to maternity roosts, could well reveal different

patterns of use.


14

Where bats are present only in low numbers, the acoustic method may have failed to

detect them. This is a particular difficulty for species with quiet or highly directional calls

(such as long-eared Plecotus spp., Bechstein Myotis bechsteinii and horseshoe bats

Rhinolophus spp.). Equally, it is not always possible to distinguish species via the

acoustic method; for example there is some overlap between the peak frequency of calls

of the soprano pipistrelle and the common pipistrelle, and Myotis bats are not commonly

identified to species level on the basis of their echolocation calls as, again, they can have

overlapping parameters.

There are also inevitably confounding effects between location and time of night.

Walking the transect route repeatedly over the three hour period will have partially

overcome this limitation. A consistent transect route was used throughout the three

surveys to enable comparisons to be made between the same locations across the

season. Where overlaps in the transect route occur (routes never actually overlap but

sections will tend to ‘meet’ occasionally) there is the possibility of false hotspots being

assumed and as such the results of these surveys should be considered in this light.


15

8. References Bat Conservation Trust (2012). Bat Surveys – Good Practice Guidelines 2nd Edition.

London: Bat Conservation Trust.

HM Government (1981). The Wildlife and Countryside Act 1981 (as amended). London:

HMSO.

HM Government (2010). The Conservation of Habitats and Species Regulations 2010.

London: HMSO.

HM Government (2000). The Countryside and Rights of Way Act 2000. London: HMSO.

Simecology Ltd (2009). Bat detector transect surveys. Quakers Walk, Devizes 2009.

Batheaston: Simecology Ltd.

Cover image: © Copyright Maurice Pullin and licensed for reuse under this Creative

Commons Licence. Online: http://www.geograph.org.uk/photo/2939897 [accessed:

04/12/14]

http://www.geograph.org.uk/profile/14368

http://creativecommons.org/licenses/by-sa/2.0/

http://creativecommons.org/licenses/by-sa/2.0/

http://www.geograph.org.uk/photo/2939897


16

9. Figure 1: Survey area & transect route

Plan of the site showing the transect route, point counts (PC1, PC2 etc.) and the direction

in which the transect was carried out. The dark line from lower left to top middle is the

tree line along Quakers Walk. The Avon & Kennet Canal runs along the bottom.


17

10. Figure 2: Graph of bat activity

Chart showing the relative activity levels of each bat species recorded at the site during

the surveys. It can clearly be seen that there was a relatively constant level of bat activity

throughout the season.


18

11. Figure 3: Aerial image of site

Aerial image of the site highlighting its position in the wider landscape. The new

development on the adjoining land can clearly been seen to the north-east of the

highlighted area. The tree line along Quaker Walk can also be seen running SW to NE to

the left of the survey area, providing connectivity with the wooded area to the north and

the canal to the south.


19

12. Figure 4: Bat Distribution The data collected by the Elekon Batlogger during the three surveys includes GPS data

for each bat (or bats depending on what was recorded on each track) and as such can be

plotted on an appropriate mapping application to give an indication of distribution. The

following aerial images show distribution data for each survey event.

N.B. This data captures a moment in bat activity and relies on an accurate GPS fix at the

time the track (each track could contain calls from 2 or more bats) is recorded. These

images should therefore only be used to give an idea of distribution as opposed to an

absolute measure of where each individual bat was at a given time.

A - Transect survey: 12/06/14. Position of Lesser horseshoe bat shown in yellow.

LHS


20

B - Transect survey: 29/07/14.

C - Transect survey: 31/08/14. Position of Brown long-eared bat shown in yellow.

Long-eared


21

13. Appendices: Legislative context and

statutory designations

i. Legislative context This section provides a brief summary of British wildlife legislation. Specific details of

legislation for species present on site are provided in Section 2.2.

The Wildlife and Countryside Act, 1981 (as amended).

The main piece of legislation relating to nature conservation in Great Britain, which

transposes into British law the Berne, Bonn and RAMSAR Conventions, and the European

“Birds Directive” (drawn up by the European Community (EC) in response to the Berne

Convention). This legislation covers protection of wildlife (birds, other animals and

plants), Sites of Special Scientific Interest (SSSI’s) (with some SSSI’s also designated as

Special Protection Areas (SPA’s)), National Nature Reserves (NNR’s) and RAMSAR sites

(and also some other designations not strictly relevant to ecology, for example National

Parks and Public Rights of Way, which are beyond the scope of this report).

The Conservation of Habitats and Species Regulations 2010 (The “Habitats

Regulations”).

The purpose of this legislation is to consolidate and update the original Conservation

(Natural Habitats, &c.) Regulations 1994 (“the 1994 Regulations”). The objective of the

Habitats Directive is to protect biodiversity through the conservation of natural habitats

and species of wild fauna and flora. The Directive lays down rules for the protection,

management and exploitation of such habitats and species. The Habitats Regulations

transpose the Habitats Directive in England, Wales and to a limited extent Scotland by

ensuring that activities are carried out in accordance with the requirements of the

Directive.

The Countryside and Rights of Way (CRoW) Act, 2000.

This legislation applies to England and Wales only. It increases protection for SSSI’s and

strengthens protection for threatened species. It also specifies that it is the duty of Local

Authorities to further the conservation of listed habitats and species (listed originally as


22

UK BAP priority habitats and species but now covered by the UK Post-2010 Biodiversity

Framework).

The Natural Environment and Rural Communities (NERC) Act, 2006.

This legislation confers a legal duty on every public authority (including County, District

and Parish Councils) to conserve biodiversity. Section 40(1) of the Act says, ‘Every public

authority must, in exercising its functions, have regard so far as it is consistent with the

proper exercise of those functions, to the purpose of conserving biodiversity.’ The duty

came into force on 1st October 2006.

bat activity transect survey report - · pdf filebat activity transect survey report _____ the...

Documents