Climate change effects and human pressure in coastal areas of naturalistic value: a multi-technique approach applied to Cala del Cefalo (Southern Italy)

Key findings from this study

This research indicates that:

• Maximum shoreline retreat exceeded 100 m and dune toe retreat exceeded 9 m over the study period, with vegetation degradation concentrated in areas of intensive morphological change.
• Hydrodynamic modeling demonstrates severe dune system vulnerability to storm-driven overtopping and backdune flooding under current and projected climate conditions.
• A self-reinforcing feedback loop connects vegetation loss, sediment depletion, and progressive shoreline retreat, driving the system toward critical ecological thresholds.
• Existing conservation measures have not halted coupled geomorphic-ecological degradation or restored system resilience despite site designation under the Natura 2000 framework.

Overview

This study applies integrated remote sensing, photogrammetric, and hydrodynamic modeling techniques to quantify coastal morphological and ecological changes at Cala del Cefalo in Southern Italy. The research spans 70 years (1954 to present) with emphasis on pre- and post-designation phases after the site's recognition as a Site of Community Importance. The analysis addresses combined pressures from climate change, sea-level rise, and anthropogenic disturbance on a protected Mediterranean dune system.

Methods and approach

The study employed Digital Shoreline Analysis System (DSAS) to track shoreline position changes, Normalized Difference Vegetation Index (NDVI) analysis to quantify vegetation dynamics, photogrammetric surveys to measure dune toe retreat, and marine storm modeling to assess hydrodynamic vulnerability. Researchers modeled the 1999 marine storm under current topography and projected future conditions incorporating IPCC SSP5-8.5 sea-level rise scenarios (+0.71 m).

Results

Shoreline retreat reached maximum values exceeding 100 m over the 70-year period, while dune toe positions retreated more than 9 m. Differential NDVI analysis documented substantial vegetation degradation concentrated in zones experiencing intensive morphological retreat. Hydrodynamic modeling revealed that the 1999 historical storm, when simulated on current topography, would cause widespread dune overtopping and backdune flooding. When adjusted for projected sea-level rise of +0.71 m, even moderate storm magnitude events produce severe threat conditions at the dune-vegetation interface and adjacent infrastructure.

The research identified a self-reinforcing feedback mechanism linking vegetation loss, sediment depletion, and progressive shoreline retreat. This coupled system response indicates the site approaches critical ecological thresholds. Conservation designations implemented post-1999 have not arrested these coupled processes or restored system resilience.

Implications

The accelerated vulnerability of Mediterranean dune ecosystems to storm-driven marine transgression under plausible future climate scenarios necessitates comprehensive recalibration of coastal protection strategies. Current conservation frameworks appear insufficient to maintain ecological function or physical stability within sites designated for protection. Adaptive management must explicitly address the cross-scale feedback between subaerial vegetation dynamics and nearshore sediment transport processes.

The study indicates that geomorphic and ecological thresholds may be transgressed within near-term temporal horizons (years to decades) despite existing legal protection status. Future coastal management requires sediment replenishment, active vegetation restoration, and structural interventions tailored to site-specific resilience limits. Regional Mediterranean assessments should incorporate analogous multi-technique approaches to identify zones requiring intervention before irreversible transitions occur.

Scope and limitations

This summary is based on the study abstract and available metadata. It does not include a full analysis of the complete paper, supplementary materials, or underlying datasets unless explicitly stated. Findings should be interpreted in the context of the original publication.