The Impact of Dune Stabilization on the Conservation Status of Sand Dune Systems in Wales

Sand dunes in Wales are becoming increasingly stable, reducing their biodiversity value, particularly for obligate and near obligate dune species. A case study shows that in the 1950s, 75 % of one dune site consisted of mobile dunes and embryonic dune slacks with open vegetation, but by the 1990s only about 6 % of the site could be classed as mobile or open, and embryonic dune slacks were virtually non-existent. This is now considered to be a trend that has affected all dune systems in Wales and most in north-west Europe. As a result, certain plant and fungus species associated with early successional stages and invertebrates that rely on open sandy areas may be facing local extinction. Drivers influencing stabilization can be external, such as sediment supply, nutrient enrichment, climate change, and predicted sea-level rise, and internal, such as soil development, grazing management, and scrub control together with recent measures to counter stabilization. The latter includes the new restoration technique of topsoil inversion or deep ploughing, with early results suggesting success in rejuvenating sand movement. Mobilization will also enable landward migration, providing a mechanism to help conserve the overall sand body in the face of sea-level rise.