Commissioned by RSK Carter Ecological Still House Lane Bedminster Bristol BS3 4EB SOUTH SEBASTOPOL PROPOSED DEVELOPMENT INVERTEBRATE APPRAISAL Report number BS/2523/10 August 2010 Prepared by Colin Plant Associates (UK) Consultant Entomologists 14 West Road Bishops Stortford Hertfordshire CM23 3QP 01279-507697 [email protected] 1 INTRODUCTION AND METHODOLOGY 1.1 Colin Plant Associates (UK) were commissioned by RSK Carter Ecological Ltd to undertake an investigation of invertebrates at a proposed development site at South Sebastopol, neat Pontypool in South Wales. 1.2 The terrestrial site survey was required to “cover all invertebrate habitats, with a particular focus on specific habitats of known importance for invertebrates such as marshes, ancient woodland and ruderal areas, and will include survey for Coleoptera including Glow-worm. Surveys will use a combination of three techniques: • sweeping (using a standard sweep net in grasslands and scrub); • beating (using a beating tray for hedgerows and trees); and • hand searching (where appropriate, particularly in bare ground habitats)”. 1.3 Further, “an additional survey is required for late season invertebrates (e.g. the shrill carder bee Bombus sylvarum). A single site survey in August will be undertaken to coincide with peak activity”. 1.4 In terms of the aquatic element of the invertebrate survey, we were instructed that “Aquatic invertebrate survey will be carried out using a standard FBA pond net. A baseline sample will be collected from streams and the canal in order to assess diversity and conservation importance of aquatic macro-invertebrates present. Key aquatic invertebrate groups which will be identified to species include Coleoptera (Water Beetles), Heteroptera (Water bugs) and Odonata (Dragonflies), with additional groups recorded where these are of conservation importance (e.g. Diptera (Stratiomyidae-Soldierflies). Aquatic Invertebrate Survey will be carried out on a single occasion between April and May in order to provide a representative sample of species present.” 1.5 The commission was received on 29th April 2010; a total of 3 site visits was requested, with a report completed by the second week of August 2010. 1.6 The spring of 2010 was, in fact, cold and wet with most adult insects delayed in their emergence. Warm weather finally arrived at the end of the first week of June. We visited the South Sebastopol site on 28th June, 14th July and 10th August 2010. 1.7 The primary techniques used to sample terrestrial invertebrates were as follows: Sweep-netting. A stout hand-held net is moved vigorously through vegetation to dislodge resting insects. The technique may be used semi-quantitatively by timing the number of sweeps through vegetation of a similar type and counting selected groups of species. This technique is effective for many invertebrates, including several beetle families, most plant bug groups and large number of other insects that live in vegetation of this type. Beating trees and bushes. A cloth tray, held on a folding frame, is positioned below branches of trees or bushes and these are sharply tapped with a stick to dislodge insects. The same technique can be applied to tall perennial herbs and other plants that tower over a sward. Black or white trays are used depending upon which group of invertebrates has been targetted for search. Insects are collected from the tray using a pooter. This technique is effective in obtaining records of most arboreal species, including many beetle groups, bugs, caterpillars of Lepidoptera, spiders and others. South Sebastopol proposed development 2 Colin Plant Associates (UK) LLP Invertebrate Appraisal Consultant Entomologists August 2010 Report number BS/2523/10 1.8 Aquatic sampling was undertaken in a stretch of the Canal (Sample Station A – see Map 1) and in three representative locations on stretches of small streams on 28 June with some repeat sampling on 14th July. Long stretches of streams on the site remain un-sampled, although we do not believe that investigating these would significantly alter the data that we have now obtained. South Sebastopol proposed development 3 Colin Plant Associates (UK) LLP Invertebrate Appraisal Consultant Entomologists August 2010 Report number BS/2523/10 2 RESULTS OF AQUATIC INVERTEBRATE SAMPLING 2.1 Appendix 1 reports the complete list of aquatic invertebrate taxa encountered during the present survey. 2.2 It is evident that the aquatic invertebrate biodiversity of the canal is significantly greater than that of the streams, although this is unsurprising given the quite different character of these two habitat types. Nevertheless, we were surprised at the poor representation of mayflies (Ephemeroptera) and stoneflies (Plecoptera) in particular in the streams. 2.3 The invertebrate value of the streams may be limited by the fact that many sections on the site are overshadowed by trees and this reduces light penetration so limiting the development of a subaquatic flora. In turn, specialist water beetles and other invertebrates may be similarly absent. Opening up of the water courses is likely to improve their invertebrate fauna in the medium to long term. 2.4 The canal contains expected invertebrate species that are associated with still water in the South Wales region and no species of particular interest were encountered. Sampling in April/May and September/October might add to the species list currently recorded but will always be limited by the presence of carnivorous fishes. South Sebastopol proposed development 4 Colin Plant Associates (UK) LLP Invertebrate Appraisal Consultant Entomologists August 2010 Report number BS/2523/10 3 RESULTS OF TERRESTRIAL INVERTEBRATE SAMPLING 3.1 Summary 3.1.1 Appendix 2 reports the complete list of insect taxa encountered during the present survey. The list is annotated with formal National Status codes where these are better than “nationally common” and these status codes are explained in Appendix 3. 3.1.2 A total of 216 invertebrate species was recorded by us during the 2010 survey. A list generated in earlier survey by another party, who visited the site on 16th July and 2nd August 2007, contains a number of highly questionable names; that report has been ignored for the present assessment. A second list prepared from undated visits by a different party has greater acceptability although this also contains a small number of unexpected species that are not justified. We have, therefore, ignored all existing data as potentially unreliable (although some listed species have in any event been found by us in 2010). 3.1.3 The more noteworthy species recorded are now briefly discussed. 3.2 Species of conservation interest 3.2.1 Several categories of invertebrates are of raised significance in an ecological assessment. These categories are explained in Appendix 3 and the corresponding species are now examined. Legally Protected Species 3.2.2 No invertebrate species that are afforded direct legal protection under any UK or European legislation were encountered during the survey. UK Biodiversity Action Plan Priority Species 3.2.3 No UK BAP species were recorded during the survey. We specifically looked for evidence of the presence of Shrill Carder Bee (Bombus sylvarum) during August but were unable to discover this species in the study area even though we can confirm that it was on the wing at other sites in the region on that date. 3.2.4 The list of UK Biodiversity Action Plan Priority Species of moths is divided into two sections. In the first, a total of 81 species are afforded the status of UK BAP Priority Species; none of these is recorded in the surveyed area nor is any likely to be present. 3.2.5 The second section is a list of 69 species that have declined in population by a significant amount in the past 25 years. These are not yet rare and are flagged as UK BAP species “for research only”. They were inadvertently included in the overall BAP list by non-specialists. 3.2.6 This has resulted in a confusing situation; these species were not intended to be affected by the requirements of Planning Policy Statement 9: Biodiversity and Geological Conservation, published by the Office of the Deputy Prime Minister during 2005, which requires Local Authorities to take measures to protect the habitats of UK BAP species from further decline through policies in local development documents. They were merely flagged for special attention. 3.2.7 At South Sebastopol we have recorded two such “Research Only” moth species. South Sebastopol proposed development 5 Colin Plant Associates (UK) LLP Invertebrate Appraisal Consultant Entomologists August 2010 Report number BS/2523/10 The Cinnabar Moth (Tyria jacobaeae) has distinctive black and yellow-striped caterpillars which feed in the flower-heads of ragwort plants and are familiar to most people. The species is widespread and abundant across southern Britain where the foodplant is a notifiable weed species. The Blood-vein moth (Timandra comae) is associated with various plants in the family Polygonaceae and is typically a species of edge habitats such as hedge banks, verges and woodland rides. IT has a wide distribution that affects all of England and Wales. Red Data Book Species 3.2.8 No species listed in the British Red Data Books (Shirt, 1987; Bratton, 1991) or which has been elevated to the status of Critically Endangered, Endangered, Nationally Vulnerable or Near Threatened (formerly Nationally Rare) by subsequent formal reviews are recorded in the present survey. Nationally Scarce Species