Landscape-scale environmental drivers of coastal dune mobility

Coastal dune habitats provide a diversity of habitats for rare and threatened plants and animals. The movement of windblown sand within these dune systems is critical to maintaining a high level of biodiversity as it creates a mosaic of habitats.

The conservation status of mobile coastal sand dunes in the UK has declined dramatically in the last fifty years as vegetation cover has increased. As a result, managers of coastal sand dunes, including Natural England and National Resource Wales, have implemented habitat restoration interventions, including the removal of invasive species and mature vegetation.

Principle Investigator Thomas Smyth introduces the project in this short video

The most efficient strategy to improve the short-term mobility of sand has been the large-scale removal of vegetation and excavation of trough and bowl-shaped depressions in locations where mobile dunes previously existed. This technique, however, is expensive and evidence from similar dune remobilisation efforts in the Netherlands and Canada have reported that the mobility of these dunes is not sustained after management interventions, resulting in revegetation.

Using a combination of remote sensing and in-situ measurements, this project statistically identified the landscape-scale factors that correlate with existing mobile dunes in the UK landscape. This information was discussed and disseminated with key stakeholders. The knowledge gained from the research will help to guide decision making with regards to the technique, location, and scale of dune rehabilitation interventions throughout the UK and around the world.

Key findings

Land cover change in sand dunes is typically measured using aerial photography and/or satellite imagery. The project quantified the accuracy of remotely sensed data in coastal dune environments with ground-truthed measurements. The results demonstrate that measurements of bare sand and vegetation cover are highly variable and caution should be used when interpreting trends and changes in land cover classification.

The key recommendation from the project is that analysis of bare sand and vegetation cover in dunes should be based on multiple replicates using supervised classification, employing the highest resolution imagery available, and that all results presented should also include the range measured by multiple replicates.