ESSEX BAP GRASSLAND STUDY Final Report for Essex Biodiversity Project and Essex County Council September 2011 Client: Essex Biodiversity Project and Essex County Council Title: Essex BAP Grassland Study Project No: 403 Date of Issue: 22 September 2011 (V3) Status: Final Signed on behalf of Applied Ecology Ltd: Dr Duncan Painter Director CONTACT DETAILS: APPLIED ECOLOGY LTD St. John's Innovation Centre Cowley Road Cambridge CB4 0WS Tel: 01223 422 116 Fax: 01223 420 844 Mobile: 07725 811 777 Email: [email protected] Essex BAP Grassland Study Final Report Contents 1 Introduction ............................................................................................................................1 1.1 Background..............................................................................................................................1 2 Grassland Inventory..............................................................................................................2 2.1 Methods....................................................................................................................................2 2.2 Results.......................................................................................................................................4 2.3 Conclusions..............................................................................................................................8 3 Grassland Types.....................................................................................................................9 3.1 Methods....................................................................................................................................9 3.2 Results of TWINSPAN Classification and Ordination (PCA) ........................................11 3.3 Grassland Vegetation Types................................................................................................15 4 Recommendations for Further Work................................................................................21 Applied Ecology Ltd Essex BAP Grassland Study Final Report 1 INTRODUCTION 1.1 BACKGROUND 1.1.1 Applied Ecology Ltd (AEL) has been commissioned by the Essex Biodiversity Project (EBP) and Essex County Council (ECC) to complete a desk-top study of Biodiversity Action Plan (BAP) grassland habitat in Essex. The study comprises two distinct elements: 1. A Geographical Information System (GIS) grassland inventory to help identify areas of BAP quality grassland within the county that could be targeted by ECC’s grazing and grassland project. The development and implementation of a conservation grazing project is a key commitment under the Essex species-rich grassland Habitat Action Plan (HAP). The inventory is restricted to grassland types that are covered by the Essex grassland HAP. 2. To analyse and interpret floristic data collected by the 1984 Essex Meadow Survey (392 individual quadrats) in order to describe the character and distribution of distinct grassland vegetation types. It is hoped that this information can be used to fine-tune the definition of important grasslands covered by the Essex species-rich grassland HAP. 1.1.2 The GIS grassland inventory has been produced in ERSI shape-file format and is provided on a CD-ROM. Chapter 2 of this report provides a summary of the grassland inventory methods and findings, and Chapter 3 outlines the methods and results of the grassland character study. Chapter 4 gives a number of recommendations for further work in order to take forward the grazing project, and are based on discussions with ECC. Applied Ecology Ltd 1 Essex BAP Grassland Study Final Report 2 GRASSLAND INVENTORY 2.1 METHODS Scope of the Grassland Inventory 2.1.1 From the outset of the project it was agreed that the grassland inventory would be restricted to grassland types that are covered by the Essex species-rich grassland HAP, and would therefore exclude areas of coastal grazing marsh, including some important grassland areas along sea walls. The reason for excluding these grassland types was not only related to their omission from the grassland HAP, but also the lack of sufficient data to enable areas of species-rich grazing marsh to be filtered from species-poor examples. In addition, road verges and other specific grassland types included within the Essex Grassland HAP were excluded because they were not considered appropriate targets for future grazing management. Production of GIS Base Layer 2.1.2 A map based grassland inventory for the county has been produced using Geographical Information System (GIS) software (ESRI ArcEditor, version 10.0) to manipulate and analyse existing spatial data-sets. Four GIS data-sets were used to create the inventory: 1. Sites of Special Scientific Interest (SSSIs) - Downloaded from Natural England’s website (March 2011); 2. Essex Local Wildlife Sites (LoWS’s) - Provided by Essex County Council (March 2011); 3. Environmental Stewardship (‘beneficial options’) – Provided by Natural England (March 2011); 4. UK Biodiversity Action Plan (BAP) inventory for Lowland Meadows (version 2.01), Undetermined grassland (version 2.01), Lowland Dry Acid Grassland (version 2.01), Lowland Calcareous Grassland (version 2.01) and Coastal and Floodplain Grazing Marsh (version 1.1, inland wet grassland sites only) – Downloaded from Natural England’s website (March 2011). 2.1.3 Data-sets 1-3 included data covering a wide range of ecologically important habitat types, and were therefore filtered in advance of merging to remove any Applied Ecology Ltd 2 Essex BAP Grassland Study Final Report parcels of non-grassland habitat. Each data-set was also filtered to remove specific grassland types outside of the grassland HAP definition (e.g. wood pasture and post-industrial sites), and where possible, areas of species-rich grassland were specifically identified and selected for. Once filtered, the four data-sets were merged in GIS to create a single base layer. 2.1.4 Further editing of the base layer was completed by interrogating OS MasterMap data and high-resolution aerial photographs. This included removal of significant and visually distinct areas of non-grassland habitat (e.g. woodland, dense scrub and large water bodies), grassland areas clearly comprising improved or amenity swards, and any grassland areas considered unsuitable for future grazing for practical reasons (e.g. roadside verges and other very linear sites, sea-walls, golf courses, churchyards and cemeteries). Any remaining sites less than 1ha in extent, where grazing is not considered a realistic management option, were also removed from the inventory. 2.1.5 The GIS layer resulting from this process of filtering, merging and editing, formed the basis for the Essex grassland inventory. Attribute Data 2.1.6 Details of the attribute data recorded for each inventory grassland site are provided in Table 2.1. Table 2.1: Details of attribute data Attribute Details Grassland ref Unique AEL reference number SSSI or LoWSs Unique reference/code for any associated SSSI or LoWS ref Name The site name has been based on a parcels data-set origin, for example parcels identified from the SSSI or LoWS citation retain the designated site name. For undesignated grasslands parcels the site name has been based on other data sources, with a generic name followed by a sequential number e.g. ‘Stewardship 1’ for a site identified from NEs Environmental Stewardship dataset. For sites where more than two mappable BAP types occurred these were split into different polygons and a numeric was used to differentiate them. e.g. ‘Roding Valley 1’ & ‘Roding Valley 2’. Area Extent in hectares (ha) Applied Ecology Ltd 3 Essex BAP Grassland Study Final Report Primary BAP Each grassland parcel included in the inventory has been type assigned to at least one of the four important grassland types listed by the Essex Grassland HAP. These are (i) neutral meadows and pastures; (ii) calcareous grassland; (iii) Thames terrace grassland; and (iv) acid grassland. Where possible the habitat descriptions provided in SSSI and LoWS citations have been used to assigned HAP type, but for land areas without statutory or non-statutory designation the grassland type has been assigned using interpretation of aerial photographs and geology/topography. Secondary BAP Where citation information indicated the presence of more type than one HAP grassland type, additional grassland types (as listed above) have also been listed. Presence of wet The presence/absence of wet grassland was recorded grassland where possible using available information. Interpretation 3 = High - BAP grassland present in polygon and extent is confidence: certain; likelihood of 2 = Medium - BAP grassland present in polygon, but extent HAP grassland is uncertain; being present 1 = Low - BAP grassland maybe present, but extent is unknown. Designation Indicates if any of the land area possesses SSSI or LoWS designation. UK BAP Attributed if grassland is included in one of the following inventory type Natural England’s UK BAP GIS inventory layers: Lowland meadows; Lowland dry acid grassland; Lowland calcareous grassland; Coastal and floodplain grazing marsh; or Undetermined grassland. UK BAP As above, some grassland was covered by more than one inventory 2 layer. Name of unitary, district or borough that the centre of the Local authority grassland falls within. Attributed if grassland is in one of the following Natural Stewardship England Environment Stewardship Schemes: Entry Level scheme Stewardship; Organic