Appendix 11 Lepidoptera
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VARTEG LAND RECLAMATION SCHEME LEPIDOPTERA SURVEY 2005 Contents Introduction and Methodology page 1 Results Summary page 1 Comments page 2 Recommendations page 4 References page 4 Appendix A. Species Lists for Neighbouring Areas ( The British and Castle Wood) page 5 Appendix B Results of Individual Visits to the Varteg Site page 8 Appendix C Varteg Species Lists page 12 Introduction and Methodology No earlier significant butterfly or moth records exist for this site (approx central grid reference SO261060), though there are 21 butterfly species and 84 species of macro-moth known from the area of The British and Castle Wood (SO2504) which just overlaps with the southern edge of a 2km radius circle around the Varteg site. (see Appendix A for these records). This survey was commissioned to increase knowledge of the lepidoptera of the Varteg site. The time scale involved, with the survey not starting until May and the report to be submitted by the end of August, limited what could be achieved: none of the spring or autumn macro-moths could be recorded and the lists produced should be viewed as representative of the area rather than complete species lists. Butterflies were recorded by walking a route around the site starting at the Salisbury Terrace entrance, southwards following the line of the fence to the southern boundary, climbing up to the top road, following the road northwards past the ruins of the building (“lighthouse”) before returning in a south-westerly direction to the starting point. Although similar to a transect, the route was flexible allowing detours to investigate anything of interest that was seen. Typically, the walk took 2 to 2½ hours to complete. Apart from the day-flying species which were recorded with the butterflies, the macro-moths were recorded by attraction to a 120W Mercury Vapour light operated using a generator. The light was always operated from approximately the same location (SO 26270613), chosen as being sheltered yet maintaining visibility of the light from most of the site and not likely to cause disturbance to neighbouring houses. The light was run from nightfall for at least two hours until no new species were being attracted. Other than by virtue of the presence or absence of their larval foodplants it is impossible to allocate individual species to particular parts of the site. Results Summary Five butterfly walks were carried out, viz 11th May, 9th June, 22nd June, 21st July and 17th August. Four MV light sessions were carried out, viz 29th May, 8th June, 22nd June, 10th August. Detailed results of each visit are presented in Appendix B, whilst Appendix C gives the combined species lists. In all, 19 species of butterfly and 53 species of macro-moth (including 5 daytime records) were recorded. Of these, four butterflies and five macro-moths are classified nationally as being local in their distribution, with Small Pearl-bordered Fritillary being on the list of UK Biodiversity Plan Species of Conservation Concern. Grayling has declined to such an extent nationally (an estimated 49% decline in 10km breeding squares since a 1982 survey) that it is a candidate for UK BAP status in the current review of UK BAP (reference 1). 1 Comments 1. Wind plays an important part in the lepidoptera ecology of the Varteg area. There was a significant breeze blowing on every one of the nine visits, even when surrounding areas were calm. It was very noticeable with the evening visits that, for whatever reason, as the temperature cooled with the approach of nightfall the wind seemed to increase. Wind deters the flight of butterflies and moths. This was starkly demonstrated on 29th May, when despite other atmospheric conditions (cloud, temperature) being favourable no moths were recorded at all over a two-hour period because of the increasing wind strength. It is no coincidence that the most important parts of the site were all sheltered from the worst of the winds (see later discussion in comment 4). 2. Unsurprisingly in view of the habitat, many of the species recorded are grass feeders (8 butterflies, 13 macro-moths). The heather stands are also important, supporting interesting species such as Emperor Moth, Narrow-winged Pug and Common Heath. It was also apparent from the August visits that the flowering heather is an important nectar source for insects, attracting in butterflies, moths and many other insects from surrounding areas. 3. There is a strong similarity between the species lists for the Varteg site (Appendix C) and those for the combined British / Castle Wood area (Appendix A). This reflects the similarity in habitat between the two. As recording at British / Castle Wood had taken place over a period of years compared to the single part-season for Varteg, several of the important species found at British / Castle Wood may also occur at Varteg but require further recording to find them. Because of the wind factor on this site, some species may be extremely selective about which evenings they fly and can be easily missed. 4. Three main sections of the Varteg site stand out as being important for lepidoptera. These (shown in yellow on map A as areas 1, 2 and 3) correspond to OS grid references: Area 1 SO261063 Around the single remaining stone wall marked on the map as “lighthouse”. A sheltered area with excellent stands of heather, grasses, scrub and a damp area for Small Pearl-bordered Fritillary. This area has the largest count of species ( 14 butterflies and 3 day-flying moths), including Small Pearl-bordered Fritillary, Grayling, Green Hairstreak, Marbled White and Wall Brown. Area 2 SO262062 to SO262060. Adjacent to the entrance from Salisbury Terrace following the mound next to the fence southwards to the wet areas. 13 species of butterfly and 2 day-flying moths recorded. Contains Small Pearl-bordered Fritillary (SO 26205 06238), the highest count of Grayling on the whole site and Marbled White. There is a nice mosaic of grassland and heather which attracted many butterflies from outside the site for nectaring, plenty of bare and sparsely vegetated areas for the Grayling and damp hollow areas for Small Pearl-bordered Fritillary. Area 3 SO259058 to SO260058. Gulleys at the southern section of the site. Scrub, grasses and nectaring flowers such as thistles. Large numbers of the common species. 12 species of butterfly plus 2 day-flying moths. 2 MAP A – Most important areas for Lepidoptera (in yellow) 5. For the two butterflies with UK BAP or candidate UK BAP status: Small Pearl-bordered Fritillary larvae feed on viola spp, probably marsh violets in this case, in damp grassy areas. In this case they occur in hollows where water can collect and there is shelter from winds. One such hollow in area 2 is SO 26205 06238 where three Small Pearl-bordered Fritillaries were sighted. Ian Smith (pers. comm.) reported two in the northern section of area 1 at SO 261 063. Other potential sites occur where the springs emanate in the south of the Varteg site. Grayling requires dry, well-drained ground with sparse vegetation and plenty of bare, rocky, sun- baked areas. The larvae feed on fescues and other grasses, completing growth in the spring after hibernation to produce butterflies from late July to early September. Revegetating coal tips provide excellent new habitat for a species which otherwise has a largely coastal distribution in Britain and is rare inland. (ref 2). 6. Other significant butterflies include Green Hairstreak, a local species found in sheltered heather growth and Marbled White, a species very uncommon in Wales but for which Gwent is the stronghold. Amongst the macro-moths, Emperor and Narrow-winged Pug are characteristic species of large heather tracts. Small Elephant Hawk, a bedstraw-feeding local species was unusually common on the site and, interestingly, several of the specimens were much smaller than normal. 7. No significant Lepidoptera were recorded for the housing application site, only a few common species (Large White, Meadow Brown, Gatekeeper) which had probably flown from the main site. 3 Recommendations 1. My strongest recommendation is that conservation of areas 1, 2 and 3 on map 1 should be given a high priority. Thus it was disappointing during the final visit in August to find that a new track had been driven through some of the most important parts of area 1. Also, the track leading from the Salisbury Terrace entrance is encroaching very close to the Small Pearl-bordered Fritillary hollow in area 2. 2. Other areas, such as the Housing Development area and the northern tip of the site are less important for Lepidoptera. However, in any plans for the site, thought should be given to opportunities for habitat creation, particularly • creation of extra shelter from north and westerly winds using earth mounds or tree planting. • allow natural regeneration of disturbed areas rather than planting with grass or shrubs. This would provide extra sparsely vegetated areas suitable for the Grayling and an eventual patchwork of wild grasses, heather and scrub which is probably the optimum for lepidoptera on this site. • dig out extra scrapes where water can collect with a view to eventually creating damp areas suitable for violets and Small Pearl-bordered Fritillary. • leave disturbed areas where birds-foot trefoil becomes the predominant ground cover, as this is the foodplant for several butterflies and moths such as Common Blue, Burnet Companion and Burnet moths. 3. In view of the importance of shelter to Lepidoptera on the site, destruction of existing mounds should be kept to a minimum. 4. Because this survey covers only part of one season, extra work would be necessary to record the spring and autumn macro-moths.