A7.6 Terrestrial Macro-Invertebrate Survey Baseline Conditions English Heritage NEW STONEHENGE VISITOR CENTRE & ACCESS ARRANGEMENTS Terrestrial Macro-Invertebrate Survey Baseline Conditions Final February 2004 CHRIS BLANDFORD ASSOCIATES Environment Landscape Planning English Heritage NEW STONEHENGE VISITOR CENTRE & ACCESS ARRANGEMENTS Terrestrial Macro-Invertebrate Survey Baseline Conditions Final Approved by: Dominic Watkins Signed: …………………… Position: Associate Technical Director Date: 19th February 2004 CHRIS BLANDFORD ASSOCIATES Environment Landscape Planning CONTENTS PAGE 1.0 INTRODUCTION 1 2.0 SCOPE OF 2003 SURVEY 2 3.0 METHODOLOGY 3 4.0 RESULTS 11 5.0 EVALUATION 43 6.0 CONCLUSION 50 7.0 REFERENCES 52 TABLES Table 1 - Final List of Arachnida: Araneae (Spiders) Table 2 – Spider Resource Recorded from Calcareous Grassland Table 3 – Final List of Coleoptera (Beetles) Table 4 - Key Calcareous Grassland Invertebrates And their Food Plant Associations Table 5 – Final List of Hymenoptera (Ants, Bees & Wasps) Table 6 – Final List of Diptera (True Flies) Table 7 – Final Lists of Hemiptera (Terrestrial Bugs), Orthoptera (Grasshoppers & Crickets) and Dermaptera (Earwigs) Table 8 – Final List of Lepidoptera (Butterflies & Moths) Table 9 - Butterfly Transect Results Table 10 - Implied Flight Periods from Butterfly Transect Results Table 11 - Odonata Transect Results Table 12 – Final List of Molluscs (Snails only) Table 13 – Species Assessment for Stonehenge Study Area GRAPHS Graph 1 - Seasonal Variation in Species Richness and Abundance FIGURES Figure 1a – Location of Terrestrial Macro-Invertebrate Sampling Stations Figure 1b – Dragonfly Transect Sections The New Stonehenge Visitor Centre English Heritage SUMMARY As part of the Stonehenge New Visitor Centre Project, a terrestrial macro-invertebrate survey was undertaken in spring/early summer 2003, employing a variety of sampling techniques at a series of Sampling Stations within the Survey Area. This was intended to provide baseline information on targeted terrestrial macro-invertebrate groups to evaluate their ecological value and to highlight their potential within various habitats resources and at specific locations. The survey used standardised collecting techniques for beetles (Coleoptera), spiders (Arachnida: Araneae), true flies (Diptera), ants, bees and wasps (Hymenoptera), snails (Mollusca), dragonflies/damselflies (Odonata) and butterflies (Lepidoptera). These included pitfall trapping, sweep netting and hand/visual searches, with malaise traps deployed in wetland habitat beside the River Avon. The species identifications were confirmed by recognised authorities and voucher specimens of all nationally uncommon species were retained for confirmation. Overall, results for the targeted terrestrial macro-invertebrate groups revealed 776 species, with 32% of these being recognised as nationally uncommon species. Within the Survey Area, in particular the chalk grassland and floodplain fen assemblages were found to contain high numbers of nationally uncommon species and were considered to be of significant nature conservation importance. Two UK/Wiltshire BAP species were found within the chalk grassland preserves, the brown banded carder bee Bombus humilis and hornet robberfly Asilius crabroniformis, while a number of nationally uncommon bees and wasps occur within the wider landscape. The importance of considering meta- populations and interlinking wildlife corridors between sites was established. Chris Blandford Associates A7.6 Terrestrial Macro-Invertebrate Final.doc The New Stonehenge Visitor Centre English Heritage 1.0 INTRODUCTION 1.1 As part of the development of current proposals for the New Stonehenge Visitor Centre Project, ecological surveys have been undertaken evaluate the ecological resource of the area. This report sets out the surveys for terrestrial macro-invertebrates undertaken for the Environmental Impact Assessment of The Scheme. 1.2 The Survey Area includes a mosaic of habitat types that are of potential value for terrestrial macro-invertebrates, including floodplain fen habitats, calcareous grassland, scrub, wet woodland and plantation habitats. 1.3 The terrestrial macro-invertebrate assemblage found at the site is considered of interest for a number of reasons. These include the presence of nationally uncommon species and species assemblages, their role in maintaining a functional ecosystem and their role as a food source for species recognised as being of European importance. The latter includes stone-curlew and quail which are known to exist in and around the vicinity of The Scheme. Chris Blandford Associates 1/55 A7.6 Terrestrial Macro-Invertebrate Final.doc The New Stonehenge Visitor Centre English Heritage 2.0 SCOPE OF 2003 SURVEY 2.1 In 2002 a detailed field survey for terrestrial invertebrates was undertaken as part of the Stonehenge A303 Environmental Impact Assessment (Highways Agency, 2003). As many of the A303 surveys extended into the Study Area for the New Visitor Centre EIA, an agreement was made to enable information collated for the A303 EIA to be utilised in the New Visitor Centre EIA. The Study Area for the New Visitor Centre EIA is shown on Figure 1a and b. 2.2 As part of the ecological baseline surveys for the Visitor Centre Project, a number of entomological surveys were established. Habitats of potential importance for terrestrial macro-invertebrates were identified from examination of the Phase I Habitat Survey. In particular, habitats such as semi-improved and unimproved calcareous and neutral grasslands, wet marsh habitats were highlighted. A field walkover by invertebrate specialists verified habitats of potential importance for assemblages of terrestrial macro-invertebrates. Information on suitable habitat for targeted species was highlighted by the desk study. 2.3 The surveys concentrated on selected groups including targeted surveys for butterflies (Lepidoptera), dragonflies (Odonata), beetles (Coleoptera), flies (Diptera), ants, bees and wasps (Hymenoptera) and spiders (Arachnida). 2.4 The A303 terrestrial macro-invertebrate survey assessed the interest associated with over 60 sampling stations, these being set with a variety of habitats along the existing road embankments and in close proximity to the road line. Targeted surveys were undertaken for true flies (Diptera) and beetles (Coleoptera), with incidental recording of other groups. A total of 529 species were identified and these included one Nationally Endangered (RDB1), three Nationally Rare (RDB3/RDBK), 20 Nationally Scarce and 123 Nationally Local species respectively. Of relevance to the Visitor Centre Survey Area, the A303 survey found considerable terrestrial macro-invertebrate interest associated with (i) swamp vegetation beside the River Avon, immediately south of the A303 road bridge and (ii) calcareous grassland and its associated plant species. 2.5 The aims of the survey were: x To provide a snapshot of the assemblages at sites targeted for their possible importance; x To assess the importance of the assemblages within the Survey Area; and x To detect nationally uncommon species within the Survey Area. Chris Blandford Associates 2/55 A7.6 Terrestrial Macro-Invertebrate Final.doc The New Stonehenge Visitor Centre English Heritage 3.0 METHODOLOGY 3.1 Desk Study 3.1.1 Wiltshire and Swindon Biological Records Centre (WSBRC) was contacted for information regarding species lists of uncommon species for an extended study area to 2km radius from the edge of the Survey Area. 3.1.2 Additional information was gathered from previous surveys along the A303 corridor, these being Colson Stone Partnership (1994), AERC (2000) and Nicholas Pearson Associates (2002). 3.2 Survey Methodology 3.2.1 Survey methods included passive collection using pitfall traps and Malaise traps and active collection along transects/areas by means of suction sampling, sweep netting and visual counts. Fixed transects for butterflies and dragonflies were undertaken employing a strict, repeatable methodology. All techniques used are described in more detail below. Pitfall trapping 3.2.2 A series of eight pitfall trap Sampling Stations were located at eight sites (P1 to P8) within the Survey Area, see Figure 1a. The Sampling Stations were carefully selected to avoid disturbance to potential underlying archaeological interest and therefore many otherwise desirable areas, such King Barrows Ridge and the strip of plantation woodland running along the north-eastern boundary of the Cursus, were not included. 3.2.3 The resulting Sampling Stations were selected to provide baseline information on (i) floodplain fen within SNCI beside River Avon; (ii) calcareous grasslands, i.e. Strangways Grasslands, Sewage Works Grassland and Bridleway 12 Grassland; (ii) hedgerow, i.e. Countess East Railway Line, Bridleway 37 (Disused Railway Line); and (iii) plantation woodland, i.e. Half Moon Clump and Fargo Plantation. The target faunal groups were the ground-dwelling species of beetle (Coleoptera) and spider (Arachnida). 3.2.4 The pitfall traps were set in the following habitat conditions: x Floodplain Fen – traps set within dense fen habitat. Chris Blandford Associates 3/55 A7.6 Terrestrial Macro-Invertebrate Final.doc The New Stonehenge Visitor Centre English Heritage x Countess East Railway Line – traps set beneath hawthorn hedgerow beside improved grassy path, next to arable fields. x Disused Railway Line – traps set on either side of Bridleway 37 beneath linear scrub belts managed as hedgerows, near to arable