Sevenoaks Wildlife Reserve, Bradbourne Vale Road, Sevenoaks, Kent TN13 3DH
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Sevenoaks Wildlife Reserve, Bradbourne Vale Road, Sevenoaks, Kent TN13 3DH Reptile Mitigation Strategy KWT Consultancy Services KWT Consultancy Services Report Verification Client Kent Wildlife Trust Site / job Sevenoaks Wildlife Reserve, Bradbourne Vale Road, Sevenoaks, Kent TN13 3DH Central Grid Reference TQ52185636 Report Title Reptile Mitigation Strategy Report Reference ECOSER003 Quality Assurance Report Version Date Prepared By Reviewed By Approved By Draft 22 Feb 2021 Camilla Blackburn Clair Thackray BSc, PhD., Ecologist, KWT Ecologist, KWT Consultancy Consultancy Services Services Final 5 March 2021 Clair Thackray Anne Waite BSc, Vincent Ganley PhD., CBiol, MRSB Managing Director, Ecologist, KWT Project Manager, KWT Consultancy Consultancy KWT Consultancy Services Services Services This report has been prepared in accordance with British Standard 42020:2013 “Biodiversity, Code of practice for planning and development”. This report has been prepared by KWT Consultancy Services for the sole use of the client. All opinions expressed are the true and professional bona fide opinions of K WT Consultancy Services. They do not constitute professional advice and the client may wish to seek professional legal interpretation of the relevant wildlife legislation referenced in this report. Any information provided by third parties and referred to within this report has not been checked or verified by KWT Consultancy Services unless otherwise expressly stated within this document. Sevenoaks Wildlife Reserve. March 2021 Reptile Mitigation Strategy i KWT Consultancy Services Contents 1 SUMMARY 1 2 INTRODUCTION 5 2.1 Background 5 2.2 Scope of Work 5 2.3 Survey Area 6 2.4 Objectives 6 3 LEGISLATIVE AND PLANNING POLICY FRAMEWORK 9 4 METHODOLOGY 10 4.1 Desktop Study 10 4.2 Reptile Presence / Likely Absence Surveys 10 4.3 Surveying / Weather Conditions 13 4.4 Evaluation Methodology 13 4.5 Limitations 14 5 RESULTS 15 5.1 Desktop Records 15 5.2 Survey Data 15 5.3 Evaluation of Survey Results 23 5.3.1 Key Reptile Site Evaluation 23 6 IMPACT ASSESSMENT 24 7 RECOMMENDATIONS 25 7.1 Outline Mitigation Strategy 25 8 ECOLOGICAL ENHANCEMENTS 29 9 REFERENCES 30 Appendix 1. Sevenoaks Gravel Pit SSSI Schedule 31 Appendix 2. Full Reptile Survey Data 2015 – 2019 32 Appendix 3.1. Example Hibernacula Specification 83 Appendix 3.2. Example Log Pile Specification 84 Appendix 4. Example Specification for Temporary Reptile Fencing 85 Sevenoaks Wildlife Reserve. March 2021 Reptile Mitigation Strategy ii KWT Consultancy Services 1 SUMMARY INTRODUCTION Kent Wildlife Trust is seeking to obtain planning permission for improvements to the existing visitor experience at its Sevenoaks Wildlife Reserve. The land subject to development proposals comprises a c.1.75 ha area located in the south-west of Sevenoaks Wildlife Reserve and Site of Special Scientific Interest (SSSI). The site is dominated by bare ground with adjacent areas of semi-natural broadleaved woodland and dense scrub. A Preliminary Ecological Appraisal undertaken by KWT Consultancy Services identified suitable habitat for reptiles within the site and a recommendation was made to evaluate the reptile populations known to be present within the SSSI using existing survey data for 2015-2019. This report summarises the findings of the existing reptile survey data and provides recommendations for mitigation and compensation. RESULTS Sevenoaks Wildlife Reserve supports three common reptile species – slow-worms, grass snakes and viviparous lizards. Slow-worms and grass snakes have been recorded in the survey area closest to the site. IMPACT ASSESSMENT The surveys focussed on areas of neutral/grassland scrub mosaic scattered throughout the Reserve. Within the site itself, limited areas of this habitat mosaic with numerous refugia features are located to the south of the Visitor Centre building. The garden of the Tadorna education building immediately to the north of the site also supports grassland/scrub mosaic and refugia features. There are no areas of grassland/scrub mosaic within the north-east and centre of the site where the majority of groundworks will occur: the suitable habitat within these areas is limited to scattered bramble scrub and rubble piles associated with derelict buildings. A Low-Good population of slow-worm (peak count 5 – 11 individuals) and Low populations of viviparous lizard and grass snake have been confirmed as present within the main reserve. The presence of three reptile species qualifies the reserve as a Key Reptile Site of County importance. The continuity of broadleaved woodland and scattered scrub habitats between the survey zones and site, together with the records of casual observations with the Tadorna garden, indicate that a Low population of viviparous lizard and grass snake, and a Low-Good population of slow-worm, is likely to be present within the site and its immediate surroundings. The development proposals involve the demolition of five buildings and the removal of localised areas of scrub and trees in the north and east of the site to enlarge parking facilities and access routes into the reserve. Renovations will also be undertaken to the existing Visitor Centre building which will also involve localised scrub and tree clearance. The construction footprint is relatively small and much of it is on the edge of the main habitats used by reptiles. However, the vegetation clearance and construction phase of the road and parking areas and Visitor Centre renovations may lead to the accidental death of, or injury to, individual animals. The proposals and potential impacts on reptiles are described below, with the location and extent of Areas 1, 2 and 3 shown on the map at Figure 5: Area 1 – Approximately 105m2 of scattered scrub will be lost and 480m2 will be temporarily cut-back along the boundary of the southern construction area. Risk of the killing or injury of individuals of common reptile species during works. Sevenoaks Wildlife Reserve. March 2021 Reptile Mitigation Strategy 1 KWT Consultancy Services Area 2 – Approximately 180m2 of scattered scrub will be permanently lost within the Visitor Centre building construction area. Risk of the killing or injury of individuals of common reptile species during works. Area 3 – Approximately 380m2 of scrub will be permanently lost through the creation of paths, roads and parking areas. Risk of the killing or injury of individuals of common reptile species during works. Without mitigation, the above proposals would result in the temporary disturbance and/or killing or injury of individual reptiles from a population of County importance and the permanent loss of small areas of suitable habitat. All three reptile species present within the reserve are listed as Priority Species under Section 41 of the Natural Environment and Rural Communities Act (NERC, 2006). This equates to a Low-Negative impact level. OUTLINE MITIGATION STRATEGY The constraints and proposed mitigation measures are described below and summarised in Table A. Exclusion Prior to the onset of groundworks, reptile fencing will be installed along the northern and eastern boundaries of the site to prevent entry / re-entry of reptiles into the works area from adjacent suitable habitat during the construction phase. On completion of the construction period, the reptile exclusion fencing will be removed so that reptiles can return to the site. Displacement of reptiles (Refer to Figure 5 in main report for location of areas described below) Area 1 – Small areas of scattered scrub around the edges of the works area will be cut in two stages, first cut to 300mm and second cut to a minimum of 150mm. A hand / destructive search of the area will then be undertaken. These areas will be maintained at a low sward height or as bare ground for the duration of the works. Reasonable Avoidance Measures (RAMs) will be followed –stored building materials will be raised on pallets, and all spoil/rubble or vegetation piles will be isolated within bare ground or short sward vegetation – away from adjacent areas of retained vegetation. Suitable storage areas for site works infrastructure, machinery and for any construction materials or proceeds from demolition and clearance need to be identified before site works commence. Area 2 – Visitor Centre and Works Compound - Staged scrub removal and hand / destructive search of refugia will be carried out as for Area 1. RAMs will be followed to avoid animals moving into the stored materials from the lakeside and sensory garden area. Retained areas of vegetation will be protected by the installation of Heras fencing around the construction works area. Translocation Area 3 – A trapping program will be required to remove any reptiles present. Due to the limited suitability of the habitat within the site, the HGBI (1998) best practice guidance for translocations of Low populations of slow-worm, viviparous lizard and grass snake will be followed. Refugia (0.5m squares of roofing felt) will be placed throughout Area 3 at a density of 50/ha. The recommended minimum number of capture visits is 60 days – however, given the limited amount of suitable of habitat, particularly the lack of dense ground cover for slow-worm, an initial period of 15 visits will be carried out in optimal weather conditions for reptile activity (Froglife, 1999). Trapping in periods of prolonged wet or hot weather is considered unsuitable and site visits will not be carried out during such conditions. Should no reptiles be recorded during the 15 day period then two-staged vegetation