Measuring Interactions of Surface Elevation and Vegetation Dynamics on the Zandmotor Dune Landscape

Abstract

The natural functions of coastal dune systems are under threat. Rising sea level, changing wave and wind climate and increasing human activities in coastal areas lead to ‘coastal squeeze’. An option to mitigate the effects of coastal squeeze can be creating seaward space through artificial beach widening. The Zandmotor mega nourishment placed in 2011 near The Hague (The Netherlands) is used as an example of creating new coastal space. Morphological changes at the Zandmotor have been studied extensively. The sedimentation-vegetation dynamics and its influence on long-term dune landscape development remain underexplored. Here we show that the presence of vegetation has contributed significantly to the increase in dune volume on the Zandmotor landscape. We used publicly available remote sensing data: elevation maps and aerial images. We found only sedimentation in the dune area on a bi-annual scale indicating that wind does not cause erosion at this timescale. Furthermore, we found that the vegetation cover is increasing over time and is often growing around the peaks of the elevation profile. Also, vegetation often stays at/around the same location and multiplies. The presence and growth of vegetation contribute to a significant increase in dune growth, reaching up to 53 m³/m/year. Our results demonstrate that the presence of vegetation has contributed significantly to the increase in dune volume on the Zandmotor landscape. The insights about sedimentation-vegetation dynamics and its influence on dune growth, gained at the Zandmotor, may inform the development of strategies to mitigate coastal squeeze, enhance dune resilience and adapt to the challenges of climate change and human activities.