Special issue – coastal dune slack hydro-ecology

Coastal dune slack wetlands exist at the interface between land and sea. They typically occur in the low-lying areas between dune ridges where the water table remains at or near the ground surface for some or all of the year. Like many wetland habitats, the hydro-ecological conditions provide a niche in which specially adapted species can exist. Notable dune slack species with European protection include the natterjack toad (Bufo calamita) and the fen orchid (Liparis loeselii). Dune systems are amongst the most dynamic of all habitats and dune wetlands can appear or disappear in timescales comparable to human lifespans as coastal processes deposit or erode the substrates upon which they form. It is these dynamic processes that create areas of bare sand suitable for development of early successional stages of dune vegetation whilst elsewhere in the dune system natural succession drives a progression towards more mature vegetation. Over time, anthropogenic pressures including afforestation, abstraction and addition of nutrients have resulted in a decline in the quality and extent of dune habitat such that the majority of humid dune slacks across Europe are now in unfavourable condition. Management to address these pressures and improve dune habitats is underway in many countries however the complex mix of natural and anthropogenic processes that influence dune wetlands is at times difficult to disentangle making it hard to identify the most suitable management practices at particular sites. Up to now effective management of these habitats has not been supported by a coordinated presentation of the relevant research. The establishment of multidisciplinary groups such as the UK Sand Dune and Shingle Network has proved effective in bringing together the range of expertise necessary to affect change. This special issue is the result of the second meeting of the network’s Sand Dune Hydrology Group which was held in Swansea in September 2013 with the intention of supporting effective habitat management through sound science.