Executive Summary This project investigates the potential to use aerial imagery to assess change in important landscape features. The project focuses on 18 sites, seven of which have been part of a long term study on agricultural landscape change, with the other eleven sites being chosen as representative of the diversity of agricultural landscapes present in England. The first part of the project investigated what aerial imagery and supporting geographic information is readily available for the study sites and collated these data into individual project files for each site. The second part of the project identified changes in the counts and patterns of landscape features observable in modern aerial imagery taken before and after the introduction of the Environmental Stewardship Scheme. These measures were compared to the expected change based on data collected for the 1998 and 2007 Countryside Survey The key findings of this project are that significant resources are required to locate, digitise and analyse changes in landscape features from historic aerial imagery. The spatial and temporal coverage of this aerial imagery is patchy, and the amount of information that can be extracted from historic imagery can be relatively low. In contrast, the modern imagery is significantly easier to work with, having national coverage and being stored in a georeferenced digital format. The results of this study indicate that the diversity of landscape character of the study areas make it difficult to draw generalisations of the observed impact of policy in different landscape types. However, the data collated in this project along with the outputs of the previous ground based survey projects mean that the sites investigated here should make good candidate study areas for future studies relating to drivers of landscape change. Continued collection of digital aerial imagery along with access to very high resolution satellite imagery and imagery from remotely piloted vehicles would provide opportunities to undertake similar studies in the future. Page 1 Introduction The aim of this project was to convert aerial photographs, taken over 18 study areas and between the end of World War II and the present day, to a geo-referenced digital format. These were then to be combined with other digital datasets to investigate landscape change and then linked with changes in agricultural policy. The initial project plan intended to collate data across four policy periods which could be broadly defined as 1) post-war agricultural intensification (1947-1973), 2) entry into the EC and implementation of the CAP (1973- 1987), 3) CAP reform and introduction of agri-environment schemes (1987-2003), and 4) introduction of the Single Payment Scheme and Environmental Stewardship (post-2003). Work identifying imagery held by Natural England showed that firstly locating imagery for all the study areas was not feasible and secondly that where aerial photographs had been taken over the study areas, only one of the policy periods would be covered. The project was however able to supplement the historic imagery with modern digital imagery taken after 1999. The project therefore produced 18 map files containing the GIS data and modern digital imagery for all 18 study areas and including historic aerial imagery for seven of these areas. The project used a rapid visual comparison (rather than the much more time consuming full manual digitisation) for assessing change in landscape features in order to be able to assess change across all 18 sites. In order to assess all 18 sites, the project was also restricted to using only the modern (post-1999) digital imagery for this assessment of change. The changes quantified from the imagery were compared to the range of expected change for the site based on Countryside Survey data collected in 1998 and 2007. The sites were also grouped and compared according to their Agricultural Landscape Typology (ALT), with three sites belonging to each of the six typologies. While three sites is not enough to make statistical inferences from, particularly as the sites were chosen to be complementary in describing the range of landscapes within a typology rather than as replicates, some general conclusions regarding changes in the landscapes within the typology have been drawn. Page 2 Background The intention of the project was to provide the means to ‘visualise’ the effects of policy change; including the impacts resulting from regulation and agri-environment schemes, on our agricultural landscapes, and thereby inform ongoing policy evaluation and scheme development. This included consideration of both intended and unintended consequences of policy interventions in specific places, from which inferences on the wider agricultural landscape can be drawn. From 2015 onwards there will be new CAP regulations and a new agri-environment scheme which will take over from Environmental Stewardship. The outputs of this project would be able to form the basis for continued monitoring of landscape scale impacts from the changes in agricultural policy and regulation that these represent, as well as other policy drivers such as the Biodiversity 2020 (Defra 2011) targets and planning regulations. The project followed preliminary work undertaken by Natural England who had started the process of locating and cataloguing historic aerial imagery from Natural England’s archives. The project also ran parallel to a separate Defra project looking into the impact that a reduced coverage of agri-environment schemes would have upon landscape character (Project BD53031). That project mainly reported on data collated for National Character Areas (NCAs) but also involved on the ground surveys of 18 study areas representing the six Agricultural Landscape Types for England (Boatman et al 2010). The work presented in here is based on the same 18 study areas. Methods Study Site Locations Annex 1 contains a description of the key landscape features from the National Character Areas in which the study areas are located. The NCA features were used to guide the selection of the study areas to provide a complementary combination of landscape types to cover the range of landscapes found in each of the six Agricultural Landscape Typologies. These study areas comprise the seven New Agricultural Landscape (NAL) sites, which had been the location for four previous studies into changes to landscape character and features (Countryside Commission 1974, 1983, 1997, Countryside Agency 2006) and 11 other sites, chosen so that there were three study areas for each of the 6 Agricultural Landscape Types (Table 1). While three study areas per Agricultural Landscape Type is insufficient to produce 1 Report available to download from http://randd.defra.gov.uk/Default.aspx?Menu=Menu&Module=More&Location=None&Completed=0&ProjectI D=17454 Page 3 a robust generalisation of the changes in landscape feature metrics within the landscape type, the study areas can be viewed as representative case studies for the six ALTs. Table 1. Agricultural Landscape Type, National Character Area and total area for the 18 study sites. Descriptions for the NCAs can be accessed at http://www.naturalengland.org.uk/publications/nca/searchpage.aspx ALT NCA Area of Search or New Agricultural Size Landscape (ha) Chalk and Limestone East Anglian Chalk Chalk scarp south of Royston 3097 Mixed Dorset Downs and Cranborne Piddlehinton NAL 1573 Chase Yeovil Scarplands Crewkerne NAL 987 Eastern Arable Vale of York Myton on Swale NAL 1297 The Fens Prickwillow NAL 1202 Bedfordshire and Cambs. Leighton Bromswold NAL 1931 Claylands South East Mixed Thames Basin Lowlands Eastern Fringe of Guildford 1754 (Wooded) Wealden Greensand Selborne 2204 High Weald Eridge 4633 Upland North Pennines Allendale 3714 Dark Peak Edale and Hope Valley 4403 Dartmoor West of Chagford 5730 Upland Fringe Orton Fells Northern Orton Fells 3299 Manchester Pennine Fringe Oldham Fringe 2336 The Culm Hartland Peninsula and Coast 3823 Western Mixed Dunsmore and Feldon Grandborough NAL 2104 Herefordshire Lowlands Preston on Wye NAL 1360 Marshwood and Powerstock Powerstock Hills 2415 Vales Page 4 Map overlays Shapefiles of the study site boundaries were overlaid onto layers containing the 1:10000 tiles and 1:50000 map outlines to identify which flight path maps and map overlays were required. Aerial photography for the study areas was identified and digitised. Natural England holds an archive of aerial photographs taken in the period between the 1960s and the 1990s. This archive is not centrally catalogued, so appropriate images for each study area needed to be individually identified. There is some variation in how the imagery is referenced across the time periods, but the majority of the images are identified by a combination of a flight number and an image number. For a large part of the archive material that was used in this project, flight paths were recorded on acetate overlays for OS 1:50000 maps. In a smaller number of cases these flight paths were recorded on a photocopied section of a paper map. For two sites (Preston-on-Wye and Selbourne) the images had already been preselected for the study area by Natural England staff. The boundaries of the study sites were overlaid onto the OS 1:10000 Vectormap product using ArcGIS and the resulting map printed onto an A4 sheet. This allowed the analyst to visually identify the appropriate section of the 1:50000 map for a particular study site, and then to identify whether any of the flights had potentially taken photographs of the study site. The location of the images on the flight paths is only given as the centroid of the image. Flights that did not directly overfly but were close to the boundary of a study site may have taken an image which overlaps with the study site were included in the list to be scanned and georeferenced. All identified imagery was entered into the image catalogue spreadsheet (Supplementary Material: AP_Imagery.xls). The metadata fields included in the catalogue are given in Table 2.