Coastal dune fields in Ireland: rapid regional response to climatic change

Coastal dunes represent dynamic geomorphological landforms that respond to changes in climatic regimes. Their spatial and temporal evolution as landforms is dependent on sediment supply, antecedent morphology, accommodation space, and physical forcing parameters such as wind speed and direction. Contemporary (decadal) morphological behaviour is therefore driven by changes in climate which affects precipitation, temperature and wind stress. This paper examines recent historical-scale changes in the stability of coastal dune systems on the west and north coasts of Ireland using aerial photographic evidence alongside climatic data to investigate trends in dune stability. A regional scale analysis of dune sites using image analysis indicates a widespread pattern of progressive sealing of dune fields by vegetation. Results show that dune fields have undergone a rapid reduction in bare surface areas of up to 80%. In recent decades (1985 to 2005) the growing season has seen dramatic increases which have likely driven dramatic regional increases in dune vegetation growth coinciding with particularly rapid resealing events across all dune sites studied. This work demonstrates (i) that coastal dune systems have a particularly high sensitivity to climatic shifts and the relatively fast response is manifest in dramatic re-vegetation patterns; and (ii) the pattern is evident on a regional scale. The results demonstrate the rapid response of coastal dunes to climatic shifts over a very short timescale (circa 5-10 years).