Coastal Dune Assessment Tool: developing an index to support ecological evaluation and management decisions along the Irish coastline

Coastal dune environments are vulnerable systems threatened by a complex network of physical, biotic and anthropic pressures. Even though they host high biodiversity, dune habitats are deteriorating and disappearing, causing the loss of their protective role against climate hazards. Finding a repeatable methodology to assess the ecological condition of these ecosystems is important to support decision-making and preserve dune resilience. Vulnerability indices are frequently implemented to simplify the variables influencing the coastline; nonetheless, their structure varies according to the scale and the objective(s) of the study. We selected 13 sites in the Northwest of Ireland and tested a new Coastal Dune Assessment Tool, inspired by pre-existing indices. The main objective was to build a multidisciplinary index, based exclusively on quantitative indicators, able to score ecological condition at a local scale and prioritise sites in need of management actions. We implemented cluster and multivariate analysis to group sites with similar status and pressures and compared the results with a quali-quantitative index. The physical indicators presented the highest scores, and the morphology of the dune system, the presence of artificial structures and grazing played an important role in the classification. The index enabled comparisons between sites and provided useful information that could be used to select the most appropriate intervention strategies, such as determining the necessity of restoration or preservation actions. Management is often a challenging process in dynamic environments, and adapting monitoring strategies able to convey a flexible but reliable methodology is a crucial step in conservation.