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, semiprotected
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.