Scope for strategic ecological assessment of trunk-road development in England with respect to potential impacts on lowland heathland, the Dartford warbler (Sylvia undata) and the sand lizard (Lacerta agilis)

Abstract

Environmental impact assessment (EIA) has a potential role in sustainable development. However, its commonest application has been at the project level, where it fails to ensure adequate consideration of potentially serious trans-boundary, widespread, indirect, cumulative and synergistic ecological effects. The fact that ecological effects cannot be predicted or evaluated effectively if EIA is confined to single development actions and contrained by artificial boundaries is an important justification for moves towards the strategic application of EIA. The need for a more strategic approach to ecological assessment can be illustrated by reference to road development in the UK, where project-level EIA has failed to quantify the overall impact of new road development on biodiversity. Some form of strategic ecological assessment (SEcA) is required to ensure that proposed new road development is compatible with international obligations to conserve protected habitats and their associated species. In common with all forms of EIA, the effectiveness of SEcA depends on the ability to define the proposed action or set of actions and to characterize the receiving environment (baseline conditions). The ability to quantify potential impacts and to estimate their risk of occurrence is strongly dependent on the availability, accuracy, reliability and resolution of national data on the distributions of habitats, species and development proposals. This paper summarizes the results of a SEcA carried out to determine whether currently proposed road developments, when considered collectively, would be compatible with the safeguard of an internationally important and protected wildlife habitat (lowland heathland) and associated protected species. The study was carried out using a version of the Countryside Information System developed for the UK Department of the Environment by the Institute of Terrestrial Ecology. Areas of lowland heathland are identified together with «hot spots» where two protected lowland heathland species (sand lizard,Lacerta agilisand the Dartford warbler,Sylvia undataalso occur. Possible risks attributable to proposed new road development are quantified for 1 km squares and evaluated on a county basis.1998 Academic Press Limited