DAVID TYLDESLEY AND ASSOCIATES PLANNING, LANDSCAPE AND ENVIRONMENTAL CONSULTANTS Evidence to support Appropriate Assessment of development plans and projects in south-east Dorset Durwyn Liley, Ralph Clarke, David Tyldesley, John Underhill-Day & James Lowen Evidence to support Appropriate Assessment of development plans and projects in Dorset Version: FINAL Date: January 8 th 2007 Dorset County Council Contract 01/2006 Recommended citation: Liley, D., Clarke, R., Tyldesley, D., Underhill-Day, J. & Lowen, J. (2006). Evidence to support Appropriate Assessment of development plans and projects in south-east Dorset. Unpublished report, Footprint Ecology. © Dorset County Council / Footprint Ecology Ltd. Page 2 Evidence to support Appropriate Assessment of development plans and projects in Dorset Summary We provide a summary of the evidence base for the wide variety of impacts associated with urban development adjacent to heathlands and we describe how an Appropriate Assessment should consider these issues. We focus on the impacts of recreational disturbance to the Annex 1 breeding bird species, namely nightjar, woodlark and Dartford warbler. Much of the research concerning these species and disturbance has been conducted in Dorset. For both woodlark and nightjar, the numbers of birds on a site negatively correlates with the amount of housing surrounding the site, such that sites surrounded by high densities of housing support fewer birds. Within sites, woodlark density has been shown to be negatively related to counts of people. Studies of nightjar breeding success have shown that a greater proportion of nests fail on more urban heaths and that nests closer to footpaths are more likely to fail. Studies of Dartford warblers have shown that, for territories dominated by heather (but not those dominated by gorse), breeding success is negatively related to the number of people walking through a pair’s territory. There is also evidence that young Dartford warblers may be particularly vulnerable to predation from cats associated with houses adjacent to the heaths. These disturbance impacts must be considered within the context of other significant urban effects, which may act synergistically together. The greater the cumulative intensity of these effects at a site, the less significant its conservation interest is likely to be. Wild fire is a key pressure and has a serious impact on ecological integrity, destroying heathland vegetation, which—together with associated faunal communities—can take 4-20 years to re-establish. Wild fires have a higher incidence on urban heaths. Nearly 60% of uncontrolled fires can be attributed to arson; the timing of such fires suggests that children are predominantly responsible. Urban heaths may have higher densities of urban predators, notably domestic and feral cats, foxes, hedgehogs, crows and magpies. In addition to their disturbance effects, dogs may chase livestock, disturb aquatic wildlife, cause physical damage to water body structure, and enrich soil through fouling. Heathland plant communities and some associated invertebrates are vulnerable to human trampling by horses, cycles, motorcycles or feet. Ongoing fragmentation and isolation of Dorset heaths are problematic: smaller, more isolated fragments have fewer heathland indicator species and poorer characteristic heathland plant communities. Fragmentation appears to be a key cause of the decline of British sand lizards and smooth snakes. Roads exacerbate habitat fragmentation and pose barriers to invertebrate mobility. Ground and surface water pollution and air pollution have negative impacts on vegetation communities. Fly-tipping may cause eutrophication. Visitor studies have shown that the heaths are widely used for by local residents for recreation. People travel to the sites principally by car or by foot, and visit the heaths for dog walking (the main reason for people’s visits), walking, cycling, horse riding and a range of other activities. Some sites, especially in Purbeck, also attract tourists from well outside the local area. We have mapped 61 different heathland “patches”, totalling some 10,718 ha, of which 5441 ha is within the Dorset Heathlands Special Protection Area (SPA). These patches represent distinct pieces of heathland and forestry with extensive public access. All patches at least contain some land designated as SPA or are directly adjacent to the SPA. There are some 531 access points onto the patches and over 5200 car-park spaces. Most sites have open access and the only substantial areas with no public access are the sites owned by the Ministry of Defence (MoD), or are contaminated sites such as Holton Heath, which we have not Page 3 Evidence to support Appropriate Assessment of development plans and projects in Dorset considered. The designated boundaries of the SPA rarely match access boundaries and therefore we have used the boundaries of where people can go to define sites. This approach also allows us to include entire patches of extensive commercial forestry blocks such as Wareham Forest and Ringwood Forest. These forests have extensive public access and also contain patches of SPA heathland. These sites also hold large populations of Annex 1 bird species such as nightjar distributed throughout the forestry. Using existing visitor count data and interview data for different access points on both the Dorset and Thames Basin Heaths, we have explored the factors that influence the number of people using particular access points. The numbers of visitors on foot is related to the amount of housing around the heath; using the amount of housing at different distance bands from the access points, our model explains 22% of the variance in visitors arriving on foot. The number of visitors travelling to access points by car could not be explained by the amount of housing surrounding sites, suggesting that people who drive to the heaths often live some distance away, an inference confirmed by visitor data (29% of visitors to the Dorset Heaths lived over 5 km from the access point at which they were interviewed). Given that people are prepared to travel these distances and that so many of the heaths are close together, car-drivers have a wide choice of location. Only 5% of people travelling to the heaths by car choose to travel to their nearest access point with parking. There was considerable variation in the number of car-drivers visiting different sites, and we found that car-park size was the best predictor of visitor numbers. This does not necessarily imply that car-park size limits visitor numbers (indeed, regression equations suggest that car-parks are not full). It is possible that car-park locations and sizes reflect places that people choose to visit or access patterns that have become ingrained within the local population. For car-parks of a given size, there was some evidence that visitor rates declined with distance (i.e. a greater proportion of people living close to the heaths visit them). There was also evidence that the decline was shallower for larger car-parks, suggesting that, compared to small car-parks, large car-parks attract a higher proportion of people living further away from the heaths. We use this understanding to develop a model to predict visitor numbers to any access point. Foot visitors are predicted by the amount of housing surrounding the heath and car-visitors by car-park size or by a combination of car-park size and housing within 10km (we present both approaches). Using these models we predict, across all patches, c.20,000 person visits per 16 hours in August, which we suggest may equate to c.5 million person visits per annum. For every person visiting on foot there are 2.2 car visitors. We map the spatial distribution of this visitor pressure within sites and reveal that it is related to the size and shape of sites, the location of the access points, the distribution of parking spaces and the distribution of housing. We also map other (non-heathland) sites within 5 km of the heaths that we believe may attract the kind of visitors that visit the heaths. We have mapped c.3,400 ha of land (excluding the New Forest) with existing access that is currently used or promoted for recreational use – including beaches, downland, commonland, estuary shoreline, country parks and urban greenspace. We estimate more than 3000 car-park spaces are associated with these sites. Many of these alternative sites are also important for nature conservation (at both national and international levels). The current level of visitor pressure onto the heaths must therefore be understood in the context of this existing range of additional land available for people to visit. Any increase in housing is likely to increase the visitor pressure on these other sites, and further work is necessary to identify which sites have the capacity to absorb additional visitor pressure. Page 4 Evidence to support Appropriate Assessment of development plans and projects in Dorset The current levels of visitor pressure on Dorset’s heathlands are having an impact on the conservation of the European designated sites. For example, Natural England currently class a higher proportion of the more urban heaths as being in ‘unfavourable condition’. This is despite the various conservation initiatives, access management and education programmes that have been put in place in recent years. We take the housing allocation figures from the Regional Spatial Strategy and other scenarios for the period until 2026 to predict the resulting increase in visitor pressure. We tentatively suggest that visitor levels to the heaths may increase by a total of 13% as a result of new housing. We show that the increase in visitor pressure will vary across the sites and locally within sites, with potential increases in visitor pressure of up to 30% in some areas. Change is likely to be greatest at sites with large car-parks or close to the urban extension sites. We highlight Parley, Studland, Canford, Upton, Bourne Valley, Alder Hills, Talbot Heath, Hengistbury, Hurn Forest and Cannon Hill.