Greater Horseshoe Bats in South Devon – New Planning Guidance

Posted by Michael Williams - AIEEM BSc (Hons) on 7/04/2011

Natural England has issued new planning guidance in relation to greater horseshoe bats in the vicinity of the South Hams Special Area of Conservation (SAC) in South Devon.

Great Horseshoe Bats Conservation Status and Ecology

Greater horseshoe bats are among the rarest and most vulnerable of the UK’s bat species. In the last century they have seen a significant decline and there are now thought to be approximately 5500 individuals left in Britain. A significant proportion of these are found in South Devon.

Greater horseshoe bats are faithful to their roosts, returning to the same places year after year, and may use several roosts throughout the year. Several major roosts are found in the South Hams SAC. Greater horseshoe bats usually forage within approximately 4km of their roosts and change their feeding locations throughout the year, depending on the availability of invertebrate prey in certain habitats. Important habitats include cattle-grazed permanent pasture, hay meadows and wetland features. In order to commute between their roosts and foraging areas, they generally follow linear features, such as hedgerows, woodland edge and vegetated stream lines. Being sensitive to light, they tend to avoid areas with street lighting and are very infrequent in urban areas.

South Hams SAC - Greater Horseshoe Bat Consultation Zone Planning Guidance

Recent research led by Natural England has identified the key foraging areas and flightlines in and around the South Hams SAC, by combining the latest scientific methods such as radio tracking, and local records. The objective of this mapping and new guidelines is to facilitate appropriate siting, planning and design of developments in order to avoid or successfully mitigate significant impacts on the favourable conservation status of the South Hams SAC. This will ensure that there is no disturbance to significant commuting routes or foraging areas.

Strategic Flyways and Key Foraging/Sustenance Zones

The Greater Horseshoe Bat Consultation Zone Planning Guidance provides a map of the identified key foraging/sustenance zones and strategic flyways.  The South Hams SAC comprises five component sites, which range from just 3km apart up to approximately 23km apart.  A foraging/sustenance zone has been identified around each component site, which is approximately a 4km radius around each component site.  Whilst there is some overlap if some sustenance zones, in combination these cover an area in excess of 20,000ha.  The strategic flightways go beyond these 4km radius sustenance zones and connect all five components of the SAC to one another.  Each identified strategic flyway has been made 500m wide in order to offer several alternative routes, as various factors such as weather may affect the suitability of usual routes.

Development Considerations

Proposed developments that may affect the strategic flyways or foraging areas, such as wind turbines, developments with more than ten houses, developments with strong lighting or developments requiring the removal of trees and/or hedgerows will require a series of bat surveys, which will enable an assessment of the impacts of bats and habitats associated with the South Hams SAC. This information will be required to inform the need for avoidance, measures and/or formulate an effective mitigation strategy and monitoring regime post-development.

Mitigation and monitoring will be administered through a Section 106 agreement and/or a planning condition. Where all mitigation possibilities have been exhausted, compensation measures, normally in areas off-site, may be considered to offset losses within the development site.  Development proposals will need to demonstrate that there will be no detrimental impact on the ability of South Hams SAC greater horseshoe bat population to navigate and feed.  If a significant impact is likely then an Appropriate Assessment would be required under the Conservation of Habitats and Species Regulations 2010.

Survey Effort

In order to comply with the planning guidance, ten bat surveys will need to be undertaken twice a month on suitable nights between April and October. In addition, static bat detectors will also need to be deployed in suitable locations for at least 50 nights.

For minor developments, in certain circumstances it may be possible to put forward mitigation without the need for a full bat survey, however, this approach will only be suitable where it can be clearly demonstrated that the impacts of a proposed development are proven to be minor and can be fully mitigated without an impact.  Ecosulis has agreed this approach through consultation with Natural England for some projects lying partially within a strategic flyway.

The new planning guidance aims to ensure that the greater horseshoe bat population of the South Hams SAC will remain stable for years to come. It is also useful in providing a plan of the most sensitive areas, so that developers can avoid plans to build in these areas where possible, or plan well in advance for bat surveys and mitigation strategies where it is necessary to build in these areas.

Ecosulis has worked on several projects involving greater horseshoe bats in South Devon and has years of experience in undertaking the necessary bat surveys, drawing up mitigation strategies and offering the most up-to-date advice in support of planning and construction phases of development.