A National Vegetation Classification (NVC) Survey of Land East of Oxford Road, Calne, Wiltshire
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A National Vegetation Classification (NVC) Survey of Land East of Oxford Road, Calne, Wiltshire A NATIONAL VEGETATION CLASSIFICATION (NVC) SURVEY LAND EAST OF OXFORD ROAD CALNE, WILTSHIRE A National Vegetation Classification (NVC) Survey of Land East of Oxford Road, Calne, Wiltshire Page 1 A National Vegetation Classification (NVC) Survey of Land East of Oxford Road, Calne, Wiltshire A NATIONAL VEGETATION CLASSIFICATION (NVC) SURVEY LAND EAST OF OXFORD ROAD CALNE, WILTSHIRE CONTENTS 1 INTRODUCTION 2 METHODOLOGY Desk Study Fieldwork Constraints 3 RESULTS Recent Site History Soils NVC communities encountered 4 ASSESSMENT AND IMPLICATIONS 5 APPENDICES Appendix 1 Location map Appendix 2 Recent site history in aerial photographs Appendix 3 Soil profiles Appendix 4 Field 1 The plant communities along the eastern hedge boundary Appendix 5 Field 1 The open grassland communities Appendix 6 Field 2 Appendix 7 Field 2 continued. Appendix 8 Field 3 Appendix 9 Field 4 Appendix 10 Triangular Marshy area – Western basin Appendix 11 Triangular Marshy area – Eastern basin Appendix 12 Summarising diagrams A National Vegetation Classification (NVC) Survey of Land East of Oxford Road, Calne, Wiltshire Page 2 A National Vegetation Classification (NVC) Survey of Land East of Oxford Road, Calne, Wiltshire A NATIONAL VEGETATION CLASSIFICATION (NVC) SURVEY LAND EAST OF OXFORD ROAD CALNE, WILTSHIRE 1. INTRODUCTION 1.1 The land surveyed consisted of four fields lying to the east of Oxford Road, Calne, Wiltshire. Their location is indicated on the Ordnance Survey map extract and aerial photograph, Appendix 1 of this report. It is understood that the site is to be promoted for a housing development. This survey has been prepared at the request of Chalkhill Environmental Consultants on behalf of Hills Group Ltd. 1.2 The surveyor was Adrian Bayley an ecologist and ecology tutor with more than fifty years of field survey experience. He was present at the inaugural meeting which established the National Vegetation Classification (NVC) protocols and has been a keen practitioner ever since. He has run countless NVC training sessions for the Farming and Rural Conservation Agency, English Nature, Natural England and Countryside Council for Wales staff members and for students of the Open University, members of the Chartered Institute of Ecology and Environmental Management and members of the general public 1.3 The aim of this survey was to provide a description of the types and locations of the various plant communities distributed across the site, using the National Vegetation Classification as the basis for those community descriptions. 2. METHODOLOGY Desk study 2.1 A copy of the “’Extended’ Phase One Habitat Survey, Land east of Oxford Road, Calne, Wiltshire”, September, 2003, was provided by Chalkhill Environmental Consultants. 2.2 The site plan contained within that document and associated Phase 1 Target notes informed the subsequent field work. 2.3 In order to determine something of the management history of the site reference was made to Google maps. The “Show historical imagery - use the time slider to move between acquisition dates” facility was used to provide information concerning the appearance of the site in 2002, 2005, 2006 and 2009. One undated image was obtained from Bing maps which post dates 2009. A National Vegetation Classification (NVC) Survey of Land East of Oxford Road, Calne, Wiltshire Page 3 A National Vegetation Classification (NVC) Survey of Land East of Oxford Road, Calne, Wiltshire Fieldwork 2.4 A National Vegetation Classification (NVC) survey was carried out on September 8th and 9th 2015; following the guidelines set out in Rodwell, J.S. (2006) National Vegetation Classification: Users Handbook. Published by the Joint Nature Conservation Committee which is available on-line at http://jncc.defra.gov.uk/pdf/pub06_NVCusershandbook2006.pdf 2.5 In accordance with the NVC protocol soil pits were dug in all fields to determine the soil type supporting the various plant communities found. Soil texture was also determined by means of simple field tests (rubbing the soil sample between finger and thumb, balling, wiring, creating a soil ring, polishing the soil). The pH of soil samples taken from 2 - 3cms below the surface were also measured using a BDH soil test kit. Five pH tests was undertaken in each field and 6 in the marsh (marked ‘m’ on the aerial photographs). Constraints 2.6 The survey was carried out late in the survey season and it is possible that some annual and early perennial species were ‘over’. 2.7 The two southern fields (Fields 1 and 2, Appendix 1) had not been grazed for a number of years and were in transition from improved/semi-improved grassland to more rank grasslands with occasional relicts of the previous management regime occurring in small scattered pockets across them. As a consequence it was not always possible to use samples of the appropriate size (e.g. 4m x 4m quadrats) and the small isolated or irregularly shaped stands of vegetation were used to construct species lists (as opposed to Floristic Tables) from which the NVC communities were identified. 2.8 The two northern fields (Fields 3 and 4, Appendix 1) had recently been ‘topped’ (mown) and a light, sheep grazing regime introduced. Very few inflorescences remained. Considerable time was spent looking for the vegetative stem bases of a number of diagnostic grasses such as rough and smooth–stalked meadow grasses, Poa trivialis and P. pratensis, and crested dog’s tail grass, Cynosurus cristatus. A National Vegetation Classification (NVC) Survey of Land East of Oxford Road, Calne, Wiltshire Page 4 A National Vegetation Classification (NVC) Survey of Land East of Oxford Road, Calne, Wiltshire 3. RESULTS Site history 3.1 Appendix 2 provides a series of aerial photographs of the land to the east of Oxford Road, Calne. They were downloaded from the Google Earth web site, ‘historical imagery’ section. They are of varying quality and colour balance and profess to having been taken in the years 2002, 2005, 2006 and 2009. A fifth image was obtained from the Bing maps web site. It is not dated but the appearance of an additional building on the Penn Hill Industrial Estate (at the eastern end of the road separating Fields 2 and 3) indicates that it postdates the 2009 Google map. However, no exact date for the image is available. 3.2 The aerial photograph dated 2002 suggests that Field 4 has been fertilised and Fields 2 and 3 have been mown. 3.3 The colour balance in the aerial photograph dated 2005 is poor but it appears that Field 3 has been mown (and possibly Fields 2 and 4). Field 1 is already showing signs of agricultural abandonment with dead (uncut/ungrazed) vegetation developing around the field margins. 3.4 The 2006 aerial photograph shows some variation when comparing Field 2 with Fields 3 and 4. Non-the-less all three fields are still in agricultural use with no signs of ‘invasive’ vegetation along the eastern edge of Field 2. Field 1 has a tussocky appearance throughout, possibly associated with the development of Cocksfoot, Dactylis glomerata, tussocks. 3.5 The 2009 photograph is of poor quality and poor colour resolution and was taken through cloud cover. Pale dead heads of grasses interspersed with darker green patches can be seen in Field 2 and its management (mowing/grazing regime) is clearly at variance with that of Fields 3 and 4. 3.6 The post 2009 aerial photograph shows Field 1 with a mosaic of plant communities developing across it. Field 2 has a track running N-S through it and the vegetation to the east of the track is clearly different to that to the west of it, where a mosaic of vegetation types is beginning to get established. Its paler colour indicates a reduction in agricultural improvements which might include lack of fertiliser application or, more likely, a continuation of the reduced mowing/grazing regime apparent in the 2009 photograph. Such patchiness may result in a change of ‘grazers’ from e.g. sheep and/or cattle to horses. Fields 3 and 4 remain brighter green in colour with no obvious variation in the vegetation cover. There is evidence that both fields have been mown at some time in the relatively recent past. The current survey a) Soils 3.7 Appendix 3 shows the profiles of two soil sample, one taken from Field 2 and the other from Field 4. There is very little difference between these two soil profiles and all the other soils samples taken across the four fields and the marshy area. The soil A National Vegetation Classification (NVC) Survey of Land East of Oxford Road, Calne, Wiltshire Page 5 A National Vegetation Classification (NVC) Survey of Land East of Oxford Road, Calne, Wiltshire texture is that of a silty loam. The underlying bedrock is siliceous and the resultant soil type is a gleyed brown earth. The gleying is brought about by a high water table but the mottling in the upper surface layers (A and A/B) of all the soils examined suggests that seasonal water-logging at the soil surface occurs at many points across all 4 fields. The soil pH was 5.5 across all points tested. The soil is considered as ‘circum neutral’. The current survey b) The plant communities Field 1 3.8 Out of the four fields surveyed Field 1 is the one that has been subject to abandonment for the longest period. Over time a mosaic of plant communities has developed. Many of the component parts do not form large blocks of homogenous vegetation over which an appropriate size of quadrat (4m x 4m) can be placed. For smaller stands of vegetation species lists were drawn up and run through the appropriate keys.