Shifting sands shape species biodiversity

The sandy Dutch coast requires substantial upscaling of sand nourishments to keep pace with sea-level rise. This increase in volume demand requires widening the range in grain-size beyond the current target, with poorly known implications for biodiversity. This project aims to develop foundations for a framework to assess the biodiversity consequences of grain-size variation in nourishments, thereby addressing the current knowledge gap of grainsize effects on biodiversity in beach-dune systems.
To this end, we have selected five beaches that naturally differ in their grain-sizes in south Sweden. Here, the impact of grain-size can be studied independent of hydrodynamic energy, potentially offering a unique “living lab” for coastal management as an analogue for future Dutch nourishment conditions. During a targeted field campaign with students supported by practitioners and researchers, we will collect data on geomorphological and environmental properties, and species biodiversity using a wide range of conventional (plot-based assessments for plants, pit traps, soil cores for environmental characteristics) and survey techniques (drone imaging, DNA metabarcoding).
Translating species communities into functional trait communities will support transferability of results to the Dutch context,
thereby contributing to Mission 5: North Sea and Large Waters (KIA LWV). We will deliver 1) foundations for a framework to assess biodiversity consequences of grain-size variation, by 2) typology and boundary conditions of species and functional traits, as well as 3) train students in multidisciplinary research. Participation of practitioners is ensured through an end symposium with all stakeholders, co-creation of DNA-methodology with Waardenburg Ecology, and a workshop with Rijkswaterstaat to translate the findings into actionable knowledge. Taken together this project will offer 1) practical applied knowledge on patterns in beach biodiversity, 2) valuable on-site training of the next generation of professionals, and 3) a strong international basis for future collaborations between research and practitioners.