BARTY FARM, BEARSTED

Transcription

1 BARTY FARM, BEARSTED Bat Survey Report FINAL For and on behalf of CRABTREE AND CRABTREE LTD December 2014

2 Unit A3 Speldhurst Business Park, Langton Road, Speldhurst, Tunbridge Wells, Kent. TN3 0NR Telephone: Directors: H G Wrigley (née Lucking) BSc. MCIEEM, BES Corylus Ecology Ltd Registered in England No Registered Office: Henwood House, Henwood, Ashford Kent TN24 8DH VAT Reg No

3 CONTENTS Page Number 1.0 Introduction Methodology Results Evaluation Conclusions 11 References Tables Table 1 Bat tree schedule Table 2 August SMP results Table 3 September SMP results Figures Figure 1 Charts showing the species composition at each SMP Figure 2 SMP and tree location plan BARTY FARM, BEARSTED BAT SURVEY REPORT, DEC 2014

4 1.0 INTRODUCTION 1.1 A series of bat surveys have been undertaken to assess the importance of the bat assemblage within the proposed development site at Barty Farm, Bearsted, Kent, hereinafter referred to as the Site. 1.2 This report relates to a tree assessment and static detector surveys undertaken for bats in 2014 carried out following an earlier Phase 1 Habitat Survey (Barry Kemp Conservation, 2014). Bat Legislation 1.3 All British bat species receive legal protection in the United Kingdom. The Wildlife and Countryside Act 1981 (WCA) (as amended) transposes into UK law the Convention on the Conservation of European Wildlife and Natural Habitats (Bern Convention). The 1981 Act was recently amended by the Countryside and Rights of Way (CRoW) Act 2000 and the more recent Habitats Regulations amendments (2010). All British bat species are listed under Schedule 5 of the 1981 Act, and is therefore subject to the provisions of Section 9, which makes it an offence to: Intentionally kill, injure or take a bat [Section 9(1)]; Possess or control any live or dead specimen or anything derived from a bat [Section 9(2)] Intentionally or recklessly disturb a bat while it is occupying a structure or place which it uses for shelter or protection [Section 9(4)(b)]; Intentionally or recklessly obstructs access to any structure or place which a bat uses for shelter or protection [Section 9(4)(c)] Sell, offer for sale, possess or transport for the purpose of sale or publish advertisements to buy or sell a bat [section 9(5)] 1.4 Bats are also included on Annex IV of Council Directive 92/43/EEC of 21 May 1992 on the Conservation of Natural Habitats and of Wild Fauna and Flora (known as the Habitats Directive). As a result of the UK ratifying this directive, all British bats are protected under The Conservation of Habitats and Species Regulations 2010 (The Conservation Regulations). Annex IV of the Habitats Directive requires member states to construct a system of protection as outlined in Article 12, this is done through Part 3 of the Regulations whereby Regulation 41 makes it an offence to: Deliberately capture, kill or injure a bat [Regulation 41(1)(a)]; Deliberately disturb bats in such a way as to be likely to significantly affect i) the ability of any significant group of animals of that species to survive, breed or rear or nurture their young, OR ii) the local distribution of that species. [Regulation 41(1)(b) and 41(2)]; Damage or destroy a breeding site or resting place of a bat [Regulation 41(1)(d)] BARTY FARM, BEARSTED 1 BAT SURVEY REPORT DEC 2014

5 1.5 Under the law, a roost is any structure or place used for shelter or protection. This could be any structure, for example, any building or mature tree. Bats use many roost sites and feeding areas throughout the year. These vary according to bat age, condition, gender and species, as well as season and weather. Since bats tend to re-use the same roosts for generations, the roost is protected whether the bats are present or not. 1.6 In addition, four species, the two horseshoes, barbastelle and Bechstein s, are included within Annex II of the Habitats Directive for which Member States are required to designated Special Areas for Conservation (SAC s) for their protection. 1.7 The UK is a signatory to the Agreement on the Conservation of Bats in Europe, established under the Bonn Convention. The Fundamental Obligations of Article III of this Agreement require the protection of all bats and their habitats, including the identification and protection from damage or disturbance of important feeding areas for bats. Aims 1.8 The aims of the survey are: To determine the level of bat activity within the Site and, To determine the bat assemblage BARTY FARM, BEARSTED 2 BAT SURVEY REPORT DEC 2014

6 2.0 METHODOLOGY 2.1 Bat Tree Assessment A ground level investigation of all suitable trees within the Site boundary was carried out to identify bat potential. Bats may use any crack or hole (such as woodpecker holes), splits or flaking bark and ivy (JNCC, 2004). Bats will also use different roosts at different times of the year. It can therefore often be difficult to definitely locate bat roosts in trees. Field signs to look for include dark streaking below holes and crevices, droppings under access points. Chattering noises emitted by bats may also be audible, particularly during the summer, however, even where bats are known to occur, such signs are not always evident Trees were placed into one of four categories as described below in accordance with Table 8.4 page 60 of Bat Conservation Trust Good Practice Survey Guidelines 2 nd Edition 2012: 1*. Trees with multiple, highly suitable features capable of supporting larger roosts; 1. Trees with definite bat potential but supporting features suitable for use by singleton bats; 2. No obvious potential although the tree is of a size and age that elevated surveys may result in cracks or crevices being found or the tree supports some features which may have limited potential to support bats; and, 3. Trees with no potential Trees were also noted if they supported ivy Hedera Helix. Ivy can do one of two things; very old, dense ivy can provide cavities for bats between the thick interwoven stems and the tree trunk or it can conceal features in the tree itself. The former would be classed as Category 1; the latter would be Category Static Monitoring Surveys Two Wildlife Accoustics SM3 bat detectors were positioned in suitable locations. The Site is approximately 3.85ha in size which places it on the smaller end of the medium-sized site category (1-15ha) (Hundt, 2012). The majority of the Site comprises sheep pasture which is improved grassland and supports little foraging interest for bats. On the north western boundary there is a treeline and hedges form the other boundaries of the Site. With these points under consideration it was deemed that the majority of the Site holds relatively low quality habitat (Hundt, 2012). Therefore the guidelines recommend a survey effort of three visits for each season of spring, summer and autumn, comprising of walked transect surveys and static monitoring surveys Due to the homogeneity of the field which comprises the majority of the Site and lack of optimal habitats, it was considered that adequate survey data would be obtained from static monitoring rather than transect surveys. On each occasion, two static monitoring devices were set out to allow comparison across the BARTY FARM, BEARSTED 3 BAT SURVEY REPORT DEC 2014

7 Site and increase the volume of data obtained. Due to time constraints, surveys were not undertaken in spring but in August (summer) and September (autumn). Although the survey effort is below the guidance in Hundt (2012), it was assessed as being appropriate for this Site and understood to provide sufficient data to evaluate the value of the Site for foraging and commuting bats The sonograms from the static monitoring surveys were subsequently up-loaded onto the computer software Analook. The sonograms were analysed and compared to identification parameters given in Parsons and Jones (2000) and Russ (1999), and also compared with library recordings made by the surveyors. It should be noted that it is not always possible to identify each bat pass to species level due either to poor recordings of their echolocations or due to similarities between echolocations of bat species not allowing confidence of identification. It should also be noted that bats will vary their echolocation in different habitats and their calls may therefore not always resemble typical echolocation calls. Where identification has not been possible suggestions of likely bat species have been provided The pipistrelle bats can often be confidently identified by the frequency at which the peak energy is recorded, around 45kHz for the 45kHz pipistrelle and around 55kHz for the 55kHz pipistrelle. However, there is a level of overlap, for example Russ (1999) records the 55kHz pipistrelle s peak frequency to be as low as 48.8kHz, whilst that of the 45kHz pipistrelle may be as high as 49.5kHz. Where sonograms show the peak frequency within this overlap this is recorded as an unidentified pipistrelle unless another feature such as a social call can be used to differentiate the bat to species level. Where pipistrelles were recorded the peak frequency recorded has been checked The Myotis genus is generally the hardest to separate to species level due to the plasticity of the calls and overlapping of call characteristics between the different species. Where the sonogram quality has allowed, parameters including call duration, pulse interval, start frequency, end frequency and peak energy have been recorded BARTY FARM, BEARSTED 4 BAT SURVEY REPORT DEC 2014

8 3.0 RESULTS 3.1 Bat Tree Assessment Nine trees were assessed on the Site for their potential to support bats; the survey was carried out on the 22 nd of August 2014 by Christian Gunn of Corylus Ecology. Of these, three were classed as category one trees: an ash (T4), a sycamore (T6) and an oak tree (T7). These three trees are all situated on the north western boundary of the Site. The remaining six trees were classed as category 2. The following table summarises the bat potential identified: Table 1 - Bat Tree Schedule ID Species Category Features Ivy T1 Walnut 2 There is a hole where a branch has rotted away, Yes - light coverage but this may not lead in and it is partially upward facing. There is some raised and lifted bark, although the cracks are small. T2 Ash 2 There is a hole on one of the branches at None approximately 4.5m on the southern side. This is a scar from a fallen limb which is partially healed and may not extend. T3 Cherry 2 No visible features, but the ivy may conceal Yes - dense coverage something underneath. T4 Ash 1 There is a hole on a split branch overhanging the None field edge at approximately 5m. T5 Oak 2 No visible features, but the light ivy coverage up Yes - light coverage to 6m from the base may conceal a small feature. T6 Sycamore 1 The tree is dying and there is lots of bark lost, Yes - light coverage especially from the upper branches. There is also a section of raised bark at 9-10m. T7 Oak 1 There is a dead split branch at 8m which provides None a suitable feature. T8 Lucombe oak 2 No visible features, but dense ivy covers the tree Yes - dense coverage from root to crown; this may conceal any features. T9 Elm 2 There is raised bark on a dead limb which overhangs the Site boundary. Yes - light coverage 3.2 Static Monitoring Surveys Two static monitoring devices were set out at Static Monitoring Points (SMPs) for four nights in August and three nights in September Two SMPs were used: SMP 1 was located at the southern tip of the Site in a hawthorn hedge, and SMP 2 was on the north western edge of the Site adjacent to the fence. These are shown on the map in Figure BARTY FARM, BEARSTED 5 BAT SURVEY REPORT DEC 2014

9 22 nd 25 th August Four full nights activity were recorded and all bat sounds files were identified. Five species of bat were identified and the dominant species was the 45kHz pipistrelle bat: 378 out of a total of 444 bat passes were attributable to this species, constituting 85% of the total. The second most abundant species were different at the two SMPs: at SMP1 noctule bats constituted 4.8% of the total passes and at SMP2 16.9% of the passes were by 55kHz pipistrelle bats. There were slightly more bat passes recorded at SMP1 than at SMP2: 249 compared to The species diversity was similar at both SMPs, with species from the Myotis and Nyctalus genera identified at both locations. It was considered that some of the Nyctalus passes at SMP1 were by Leisler s bat, whilst none of the passes at SMP2 fitted within the parameters of the calls for this species. It is recognised, however, that there is a degree of plasticity of the calls of the Nyctalus species. The two Nyctalus species together (noctule and Leisler s bat) contributed a total of eighteen passes at SMP1: this was 7.2% of the total passes compared to 1% at SMP Regarding the timing of bat calls, there was a fairly even distribution across the four nights. The peak and lowest numbers of bats were on opposite nights at different SMPs: at SMP1 the peak was on the 23 rd of August and the lowest number of bats was on the 25 th, and at SMP2 the exact opposite occurred, with the peak on the 25 th and the lowest number on the 23 rd. The earliest bat passes were more consistent at SMP1 than at SMP2: at SMP1 the earliest emergence times were similar on all four nights, and were an average of 17 minutes after sunset. However, at SMP2 on the 22 nd and 25 th of August the earliest bat passes occurred very late: 64 minutes and 71 minutes after sunset respectively, with the first bats at 12 and 19 minutes after sunset on the other two nights. A summary of the bat passes recorded at each SMP is presented in Table 2. Table 2 - Summary of August Static Survey Data August SMP 1 August SMP 2 Species Passes % Species Passes % P P P P Pipistrelle Pipistrelle 2 1 Noctule Myotis Leisler s 5 2 Nyctalus Myotis Noctule Nyctalus Total 195 Total BARTY FARM, BEARSTED 6 BAT SURVEY REPORT DEC 2014

10 12 th 14 th September Three full nights activity were recorded with all bat sound files identified. Six species were identified on Site in total and the dominant species was the 45kHz pipistrelle bat: out of a total of 188 passes, 116 were made from this species, constituting 62% of the total. Like in August, the 55kHz pipistrelle bat was the second most abundant species at SMP2, with sixteen passes out of a total of forty five. At SMP1 the second most abundant species was Leisler s bat: seventeen out of the 143 passes at this location were by this species, which was not recorded at SMP2 in September or August There were more than three times as many passes at SMP1 than at SMP2. There was also greater species diversity at SMP1 and, like in August, Nyctalus species were abundant: 19.6% of the total calls at SMP1 were attributable to species from this genus. Nathusius pipistrelle, which was not recorded in August, was identified at both SMPs Regarding the timing of the bat calls, at SMP1 there was a relatively even distribution of calls across the three nights: 50 on the 12 th of September, 59 on the 13 th and 34 on the 14 th. In contrast, at SMP2 there were 31 passes on the 12 th, only 14 on the 13 th and no passes on the 14 th. The first bat passes were, like in August, more consistent across the three nights at SMP1 than at SMP2. The first bat pass at SMP1 occurred at an average of 25 minutes after sunset, whereas at SMP2 the first bat pass on the 12 th was at 1hr 36 minutes after sunset and at 18 minutes after sunset on the 13 th. The earliest bat passes on the 20 th of September at SMP1 were at 21 minutes after sunset by two pipistrelle bats and a noctule. Noctule bats emerge early from their roosts at an average time of 5 minutes after sunset (Altringham 2003), so this noctule emergence was relatively late compared to typical emergence times. A summary of the bat passes recorded at each SMP is presented in Table 3. Table 3 - Summary of September Static Survey Data September SMP 1 September SMP 2 Species Passes % Species Passes % P P P P Pipistrelle Noctule Leisler s Nyctalus Noctule Nathusius Myotis Total 45 Nathusius Total BARTY FARM, BEARSTED 7 BAT SURVEY REPORT DEC 2014

11 4.0 EVALUATION AND RECOMMENDATIONS 4.1 The proposals for the Site include the construction of a new housing development with 122 units, parking and associated landscaping, however, design plans are not currently available to assess impacts. 4.2 At least six species of bats have been recorded using the Site during the surveys. These were: 45kHz pipistrelle 55kHz pipistrelle Nathusius pipistrelle Noctule Leisler s Bats from Myotis genus 4.3 At SMP1 marginally higher levels of bat activity were recorded across the two surveys, with 392 passes here compared to 240 at SMP2. The area around SMP2 has a higher level of lighting from housing to the north-west of the Site. 4.4 As seen in Figure 1 below, the bat passes at both SMPs were dominated by 45kHz pipistrelle bats. At SMP2 a larger proportion of the bat passes were by 55kHz pipistrelle bats than at SMP1, with the species composition being more evenly distributed amongst the species other than the 45kHz pipistrelle at SMP1. Here, a relatively large proportion of bat passes were attributable to species from the Nyctalus genus: Leisler s and noctule bats were fairly abundant, whereas at SMP2 only 2.5% of calls were by bats from this genus. Low numbers of Nathusius pipistrelle were identified at both SMPs during September but not in August. Figure 1 Charts showing the species composition at each SMP SMP1 species composition 79.8% P45 P55 Noc Leis Myo Nyct Pip Nath SMP2 species composition 75.4% P45 P55 Noc Leis Myo Nyct Pip Nath BARTY FARM, BEARSTED 8 BAT SURVEY REPORT DEC 2014

12 4.5 At SMP1, during both the August and September surveys, the earliest bat passes recorded on each night were more consistent than at SMP2. On average at SMP1 the first bat pass was recorded at 20minutes after sunset, with a range of minutes after sunset. In contrast, the earliest bat pass at SMP2 varied greatly from night to night, ranging from 12 minutes to 1hr 36 minutes after sunset. A reason for this may be that bats were entering the Site from the south, such as from Common Wood: the woodland is situated approximately 150m to the south east of the Site. They may then have moved towards the north of the Site slowly, foraging along the hedgerows on their way. 4.6 The following measures, which are discussed below, will help to lessen impacts and ensure the viability of the local population of bats: Retaining existing trees, plant hedgerows and generous native planting to provide linked foraging habitat. Meadows and rough grassland are also good habitats to include for invertebrates. Adoption of a sensitive lighting strategy Incorporation of bat boxes into new buildings 4.7 It was recommended within the Phase 1 Habitat Survey Report (Barry Kemp Conservation, 2014) that the hedgerows and treeline should be retained. The static monitoring surveys recorded moderate levels of bat activity within the Site, and the bat tree assessment identified potential bat features on several trees on the north-west boundary. The advice to retain these boundary features therefore still stands; they should not be removed due to their potential importance to foraging and roosting bats. There should be generous native planting throughout the Site to encourage biodiversity including foraging resources (insects) for bats. 4.8 As the proposals for the Site are to build 122 new homes, there will be an increase in lighting in and around the Site. Inappropriate lighting design would have a significant detrimental effect on the local bat assemblage. The greatest effect would likely arise from new lighting columns being installed, however, inappropriately positioned smaller lighting features, such as bollard lights, can have a similar negative impact. 4.9 For the reasons stated above, a sympathetic lighting strategy will need to be devised in consultation with the project ecologist. This will involve minimal use of lighting columns and, where they are needed, light spill from them will be kept to a minimum. Low bollard lighting with downward facing shields and infrared motion sensor lights will also be included in the strategy to keep upward light spill and the time that exterior house lights are on to a minimum. The following general measures are recommended, taking into account current best practice guidance (page 28, Landscape and Urban Design for Bats and Biodiversity, Bat Conservation Trust, 2012): Do not provide excessive lighting; use only the minimum amount of light needed for safety BARTY FARM, BEARSTED 9 BAT SURVEY REPORT DEC 2014

13 Minimise light spill by eliminating any bare bulbs and upward pointing light. The spread of light should be kept near to or below the horizontal; flat cut-off lanterns are best. Use narrow spectrum bulbs to lower the range of bat species affected by the lighting. Use light sources that emit minimal ultra-violet light and avoid the white and blue wavelengths of the light spectrum to avoid attracting lots of insects. Lighting regimes which attract large numbers of insects result in a loss of insects from other areas, such as parks and gardens, which bats may also be using for foraging. Lights should peak higher than 550nm or glass lantern covers should be used to filter UV light. Whilst white LED lights do not emit UV, they have still be shown to disturb slow-flying bat species. Reduce the height of lighting columns; light at a low level reduces the impact on bats. However, higher mounting allows for lower main beam angles, which can assist in reducing glare. For pedestrians, use low level lighting that is as directional as possible and below 3 lux at ground level; it is preferable that it is below 1 lux if possible. Increase the spacing of lanterns and avoid using reflective surfaces under lights. Use embedded road lights to illuminate the roadway and light only high risk stretches of road, such as crossings and junctions. Limit the times that lights are on, using timers, in order to provide some dark periods. Use lighting design software and professional lighting designers to predict where light spill will occur. Use temporary close-boarded fencing until vegetation matures to shield sensitive areas from lighting It is recommended that integrated bat boxes are included in the new houses to provide potential roosting spaces for bats. A total of 15 bat boxes such as the 1FR should be installed on the south and east elevations of the houses, at eaves height BARTY FARM, BEARSTED 10 BAT SURVEY REPORT DEC 2014

14 5.0 CONCLUSIONS 5.1 Bat surveys undertaken during August and September 2014 identified moderate levels of bat activity at the Site, with a moderate species diversity. The southern area of the Site appears to attract more bat activity, possibly due to the higher light levels towards the north. 5.2 In several of the trees on the north western boundary of the Site potential bat features were identified. It is not proposed to remove these trees as part of the development. 5.3 To maintain the value of the Site for the local population of bats, it is recommended that the treeline and hedgerows around the perimeter of the Site are retained and additional generous native planting is provided within the landscape designs. A sympathetic lighting strategy is recommended in order to minimise the effects of lighting on foraging bats and provisions for roosting bats should be incorporated into the new buildings BARTY FARM, BEARSTED 11 BAT SURVEY REPORT DEC 2014

15 REFERENCES Altringham, J British Bats. The New Naturalist Gunnell K., Grant G. and Williams C Landscape and Urban Design for Bats and Biodiversity, Bat Conservation Trust Hundt, L Bat Surveys: Good Practice Guidelines, 2 nd edition. Bat Conservation Trust. Russ, J The Bats of Britain and Ireland. Alana Ecology Ltd Parsons, S. & Jones, G Acoustic identification of twelve species of echolocating bat by discriminant function analysis and artificial neural networks. The Journal of Experimental Biology 203: JNCC The Batworkers Handbook BARTY FARM, BEARSTED 12 BAT SURVEY REPORT DEC 2014

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