Varteg Lepidoptera Survey 2010 Andrew King and Norman Lowe for Hawkeswood Ecology Third Party Disclaimer Any disclosure of this report to a third party is subject to this disclaimer. The report was prepared at the instruction of, and for use by, our client named on the front of the report. It does not in any way constitute advice to any third party who is able to access it by any means. The authors exclude to the fullest extent lawfully permitted all liability whatsoever for any loss or damage howsoever arising from reliance on the contents of this report. We do not however exclude our liability (if any) for personal injury or death resulting from our negligence, for fraud or any other matter in relation to which we cannot legally exclude liability. We confirm that in preparing this Report we have exercised reasonable skill and care, taking into account the project objectives, the agreed scope of the work and prevailing site conditions. 2 CONTENTS Non Technical Summary 1. Introduction Page 1 2. Methodology Page 1 3. Survey Team Experience Page 4 4. Relevant Legislation Page 4 5. Field Survey Results Page 4 6. Evaluation of Findings 7 Impact Assessment Page 5 8. Mitigation Page 7 8. Ecological Summary of Key Features To Inform Mitigation Page 8 9. Conclusions Page 13 10. References Page 14 Appendix 1: Butterfly Survey Results Page 15 Appendix 2: Butterfly Species Recorded Page 17 Appendix 3: Moth Survey Results Page 19 Appendix 4: Moth Species Recorded Page 24 Appendix 5: Site Map Page 27 Varteg Lepidoptera Survey 2010 NON TECHNICAL SUMMARY The authors were commissioned by Hawkeswood Ecology to undertake an assessment of the Varteg land reclamation site to provide a report on the populations of butterflies and moths (Lepidoptera), concentrating especially on those species with statutory protection and including an account of impacts and possible mitigation of this coal recovery site. The report was intended to build on a previous site survey of Lepidoptera carried out in 2005. The present survey focussed on operational areas and targeted habitats most likely to support a good representative range of Lepidoptera. Some off-site areas were also surveyed where these were considered to be important supporting habitat. Butterflies and day-flying moths were recorded by walking a route around the site that included the majority of habitats. Night-flying moths were recorded in the main by attracting them to ultra-violet light, though other techniques such as netting at dusk and attracting to sugar were also used. A total of 107 species of Lepidoptera was recorded, made up of 19 species of butterfly and 88 species of moth. Four species of butterfly are so-called Section 42 (S42) species, regarding which a duty is placed on the Local Authority to maintain and enhance populations. Three locally scarce butterfly species were also found. Of the moths, 11 were S42 species and a further 12 were considered to be locally scarce. Specific recommendations for mitigation and remediation in the Varteg study area are made relating to seven species of butterfly, including those four S42 species found in 2010. Less is known about the exact habitat requirements of most moths than for most species of butterfly. In consequence, although recommendations were made for mitigation and remediation relating to 25 species of moth, they are more general in nature than those relating to butterflies. 1 INTRODUCTION 1.1 The authors were commissioned by Hawkeswood Ecology to undertake an assessment of the Varteg land reclamation site (see attached plan at Appendix 5) to provide a report on the populations of butterflies and moths (Lepidoptera). The report was intended to build on a previous survey in 2005, concentrating especially on those species of conservation importance and to include an account of the likely impact of any coal recovery and proposals for subsequent mitigation. It was considered important that the survey should encompass as wide a variety of species as possible and therefore both day-flying and night-flying moths were targeted. 1.2 The objectives of the survey were summarised as: • To record species of butterflies and moths at the site; • To indicate the habitat requirements of these species, concentrating especially on those of conservation importance; • To assess the value of the site for Lepidoptera; • To identify any impacts of operations on Lepidoptera; • To provide information on mitigation. 1.3 Most species of butterflies and moths have flight periods between May and September, and in consequence the surveys were timed to cover this period of the year, although no moth survey was carried out in May as it was considered that most species flying then would also be flying in June. 2. METHODOLOGY 2.1 Overview 2.1.1 Six daytime and four dusk/night-time visits were made. On the following dates visits were made to record butterflies and day-flying moths, with searches for Lepidoptera between the 11.15 and 15.00 hours. On two of these dates (M-M) checks for larval stages of micro-moths were made: 23 May 2010 12 June 2010 17 July 2010 8 August 2010 (M-M) 27 August 2010 12 September 2010 (M-M) On the following dates dusk visits were made that extended into night-time moth- trapping until approximately 3 hours after sunset: 15 June 2010 17 July 2010 16 August 2010 9 September 2010 1 2.1.2 Butterflies and day-flying moth searches were made by following a set route (transect) around the site. The route was similar to that taken in the 2005 Lepidoptera study, with the inclusion of additional sections in the western section of the study area. The transect methodology adopted by Butterfly Conservation for their Butterfly Monitoring Scheme is based on a 5 metre x 5 metre ‘walking box’ approach. That rigid methodology was not considered appropriate for this study, a more typical search area being a band 10 metre wide by 20 metre in advance of the surveyor. This more flexible approach to recording was adopted to increase the number of species encountered, and to gain a better appreciation of numbers and habitat use by butterflies and day-flying moths. 2.1.3 Table 1 below indicates the range of habitats in each of nine transect sections. The main habitats within each section are described. An eight-figure grid reference is included within table 1 to indicate the approximate mid-point of each length. Sections 1-4 and 8-9 of the present survey had also been covered in the 2005 survey. Table 1: Habitat description of butterfly transect sections. Transect section Habitat description 1. SO26250613 Bilberry heath, bare tip, hollows with trefoil, light scrub 2. SO26200595 Dense scrub, heather heath, bramble, bare tips 3. SO26050585 Bare tips, bilberry, bracken, grasses with trefoils 4. SO25880584 Grass verges with trefoils, dry bilberry/heather heath 5. SO25630602 Grazed grass verges, marshy grassland with Juncus stands 6. SO25670634 Grazed grass haul-road, acid grasslands 7. SO25980625 Steep heather bank 8. SO26090634 Dry heath, damp hollows, hawthorns, rushes, grass verge 9. SO26200631 + Moth trapping Sparse grasslands, scant hedge, bare tip, reedmace sites A and B 2.1.4 The previous survey in 2005 had indicated that wind was a factor in effective surveying of this site for Lepidoptera. With this in mind Sections 1-9 of the daytime transect route encompassed all the primary habitats, covering the full spectrum of aspect and altitude, but as far as possible were sheltered from the prevailing SW winds.. 2.1.5 Most of the surveys covered the area of the site where it is proposed to carry out coal recovery operations. However the daytime surveys included part of the hill (section 7) running between the two arms of the impact area and which contained most of the heathland surveyed as this was considered to be an important supporting habitat. A map of the transect route, numbered sections and locations of the two moth-trapping sites can be found at Appendix 5. 2 2.1.6 On the 12 June and 8 August daytime visits, the northern section of the trackway and adjacent rank dry heathland with light scrub regeneration in the northern wedge were sampled. 2.2 Butterflies 2.2.1 Butterflies were recorded by walking a route that started at the Salisbury Terrace entrance (section 1), proceeding clockwise around the site. All nine transect sections described in Table 1 were visited on each of six visits, with the exception of 12 June 2010 when sections 1-3 were substituted for a search of damp habitats and adjoining dry heath at the north of the site. Day-flying Lepidoptera were observed, identified and counted along this route. Although similar to a transect, the route was flexible allowing detours to investigate anything of interest that was seen. Survey findings (see Appendix 1) relate solely to flying adults; no systematic searches for egg, larval or pupal life-stages were made. A butterfly net was carried but used only sparingly to confirm identification of difficult or worn individuals. Typically, the walk took just over 2 hours to complete, with the majority starting in late-morning extending to around 2pm. Weather conditions during visits were not considered a constraint, although the 8 August visit was carried out in warm but sunless conditions, and the wind-strength exceeded Force 5 on the two final visits. 2.3 Moths 2.3.1 Both day-flying and night-flying moths were recorded. Day-flying moths were noted during the butterfly surveys, but in addition searches were carried out for leaf-mining micro-moths and, opportunistically, other larvae. Night-flying moths were attracted to ultra-violet (UV) light either to a commercially-available Heath Trap or to a white sheet laid on the ground.