Prone to retreat or not: on the resilience to climate change of the Site of Community Importance (SCI) “Spiaggia del Mingardo e Scoglio di Cala del Cefalo” (Southern Italy)

Coastal dunes on sandy shores play a crucial role as a sand reservoir during storm surges. While storm-driven erosion and recovery are typical natural processes along coasts, human activities can disrupt this balance, making coastal evolution studies essential for sustainable coastal management, especially in areas with significant ecological value.

The aim of this research is to evaluate the coastal changes that have occurred since 1954 along the sandy stretch belonging to the Site of Community Importance (SCI) “Spiaggia del Mingardo e Scoglio di Cala del Cefalo,” located in the Campania Region (Southern Italy), as part of the PRIN project “GAIA,” which assesses flood risks for Italy's most significant plains and beaches.

Using an integrated GIS/Google Engine analysis of topographic maps, aerial and satellite imagery, and new high-resolution photogrammetric data, a trend of retreating shoreline and dune system has been identified. Shoreline analysis reveals that the coast has retreated by about 82 meters since 1954. However, it is important to note that this erosion has slowed significantly since the establishment of the SCI.

The intense impact of storm surges on this coastal stretch is evidenced by wash-over fans and heavily degraded vegetation cover. An inversion in the dune succession was observed through a floristic transect, with secondary vegetation extending into the hind dunes and exhibiting a high degree of salinisation. The gradual retreat of the dune is also indicated by the presence of pines along the line of secondary vegetation. Furthermore, the Normalized Difference Vegetation Index (NDVI) clearly highlights intense degradation of dune toe vegetation, severely stressed by the increasing frequency of major storm surges.

Numerical modelling revealed that even storm surges with significant heights of less than 5 meters and long wave peak periods can severely impact dune stability and flood the backshore areas. Another key finding is the estimation of flooded areas and the calculation of the run-up for high-magnitude storm surges, which ranges from 3 meters to 7.5 meters.

This study underscores the significant threat that storm surges pose to a dune system of high naturalistic value. The findings demonstrate that increased storm intensity and frequency, driven by climate change, are accelerating coastal erosion and habitat degradation. The dune system is particularly vulnerable due to its role in protecting biodiversity and maintaining coastal resilience. Effective conservation and management strategies must prioritize the monitoring of storm surge impacts and integrate climate change projections to safeguard these valuable ecosystems. Enhanced protection measures, such as adaptive management and restoration efforts, are essential to mitigate the ongoing degradation and ensure the long-term sustainability of these critical coastal habitats.