Coastal defences versus coastal ecosystems: A regional appraisal

Societal concern (both real and imagined) over coastal erosion and flooding, often results in construction of sea defences to protect property. Sea defences are, however, damaging to the natural ecosystems that provide quantifiable ecosystem services to the human population. Protection of property is, however, the most common driving force behind construction of sea defences and the basis of any associated economic appraisals. Protection of the coastal ecosystem (sedimentary, biological and chemical) while commonly implied in strategic documents (e.g. Habitats Directive 92/43/EEC, Water Framework Directive 2000/60/EC, OSPAR Convention), remain largely aspirational notions that currently have a much lower priority, or none at all, in sea defence decision-making. Under this anthropic view of coastal protection it is not surprising that defence structures proliferate. In many instances, shoreline armouring is considered on a case by case basis with little regard to the cumulative effects. This is true whether or not there is a strategic approach to coastal protection. In this paper the Northern Ireland coast is used as a case study to document the nature and extent of shoreline protection structures associated with sandy beaches. The nature and extent of sea defence structures were documented from a low-level oblique helicopter-based photographic survey and mapped in a GIS. The implications for the coastal ecosystem are considered. A sustainable approach to shoreline management demands a balance between protection of property and preservation of coastal ecosystem services.