Historic and contemporary dune inventories to assess dune vulnerability to climate change impacts

Abstract

The overall status of dune health in Ireland is assessed as ‘inadequate’ and declining due to the on-going losses and pressures which signify the urgent need for integrated, problem- and community-focussed coastal management plans. Historically, Ireland has only being monitoring the health of our coastal dunes very intermittently. This research reviews published coastal dune inventories in Ireland (Kinahan and McHenry, 1882; Young, 1977; Curtis, 1991; Quigley, 1991; Ryle et al., 2009; Delaney et al., 2013) and uses one of the most current inventories (Coastal Monitoring Project 2004-2006 in Ryle et al., 2009) to map the current distribution of dunes in thirteen coastal counties in the Republic of Ireland and assess the vulnerability of these dune ecosystems to projected changes in storminess. The CMP Report data was downloaded into a GIS and a filter query was applied to identify the dune area extent in each county and isolate the three major dune categories (Fixed, Embryonic and Mobile) which are critical for beach-dune sediment budgets via sediment exchange processes. The polygon features for each dune category (a total of 179) were designated a shoreline orientation based on the cardinal and ordinal wind directions. Counties Donegal (36%), Mayo (24%) and Kerry (14%) contain 74% of the total dune area in Ireland (c.76sq. km). Fixed dunes comprise 93% of the total dune area of interest in this study; mobile (5%) and embryonic (2%) dunes have a much smaller areal extent. The severity of the impacts from storms depends not only on the character (size, duration, direction) of the extremes but also on the exposure and vulnerability of coastal ecosystems and communities to these extremes.