Impacts of climate change on coastal habitats

Abstract

Coastal margin habitats (sand dunes and beaches, machair, saltmarsh, shingle and beaches, maritime cliffs) constitute a transition zone between terrestrial and marine habitats. They are doubly sensitive to climate change, experiencing changes in rainfall, temperature, storminess, etc., but also habitat loss due to coastal erosion and sea-level rise. Sediment supply and sediment transport are key natural processes these habitats require for a natural, dynamic state, on which their unique biodiversity depends. Coastal erosion and sea-level rise may increase or reduce sediment supply, depending on local context. However, change in the character or extent of these habitats is certain, requiring proactive management response. Where fixed landward assets prevent natural migration, habitat loss will occur due to coastal squeeze; in other locations rollback or managed realignment should be considered as management options. Coastal water tables may rise due to sea level rise, or fall due to changing rainfall, depending on local context. Both may have serious impacts on coastal biodiversity, and on other coastal land uses. Coastal margins are highly important for ecosystem service provision, primarily leisure and recreation, and coastal defence. Climate change may increase leisure uses but will create significant challenges for coastal defence, requiring integrated management of sediment budgets across all habitats.