Study of the factors affecting the vegetation of the dune system of Guardamar del Segura, Spain

Vegetation is an element of the dune ecosystem that plays a highly relevant role in coastal protection. It is essential to measure their changes with high precision and their evolution over time. Therefore, it is necessary to have a methodology and adequate means that allow us to understand the natural and anthropic impacts that promote these changes. The objective of this research is focused on knowing the relationships that affect the dune vegetation when the beach berm disappears and houses that avoid the spray from the sea are destroyed. To do this, the study has focused on the area of Babilonia Houses, Guardamar del Segura (Spain). The historical evolution of the treeline closest to the coast has been analysed from 1977 to 2022 and has been linked to the study of profiles carried out using Digital Terrain Models (DTM). In addition, the existing climate and its relationship with the vegetation index (NDVI) have been studied in three very different areas: natural area, semi-protected area and area protected by buildings. The results obtained show that the protection provided by Babilonia Houses to the dune vegetation is decisive, preventing its erosion; on the contrary, the degradation can reach 1.7 m/year in most natural sectors. However, the increase in elevation and slope as a result of the 2011 dune restoration was beneficial, stopping the erosion of the vegetation. On the other hand, the surface with NDVI>0.25 shows a strong positive linear correlation with the annual precipitation (r = 0.868), the number of hours with Hs > 2 m (r = 0.901) and the average wind speed (r = 0.858). The results of this research can be fully extrapolated to anywhere in the world and may be useful to coastal managers when making preservation decisions about a coastal system, making it last over time.

This work was funded by the European Commission through the project “Smart Control of the Climate Resilience in European Coastal Cities” (SCORE).