Long- to short-term evolution of the beach-dune systems along the physiographic unit Punta Penna–Punta Pietre Nere (Central Adriatic coast, Italy)

Coastal areas, particularly low-lying sandy coasts, represent zones of high fragility mainly due to the increasing anthropogenic pressure and the impacts of ongoing climate change. This paper analyses the long- to short-term evolution of the beach-dune systems of a 60 km long, sandy sector of the Central Adriatic coast. The study area was analysed by means of aerial photos, orthophotographs and satellite images dating from 1954 to 2022, using both the littoral cell approach and the division into coastal segments based on morphological and administrative elements. Its evolution was compared with the progressive coastal armouring and wave climate characteristics and trends. Shoreline erosion increased over the past three decades, with the period 1989–2000 resulting to be the most critical one. This period was characterized by continuous and energetic storms that, despite the extensive presence of coastal defence structures (42 %), favoured shoreline retreat especially in the southern sectors, with a maximum average rate of −3.28 m/y. Although the period between 2012 and 2022 was characterized by overall positive shoreline and dune foot trends, the southernmost sector of the study area was significantly affected by erosion, with shoreline and dune foot rates of −1.17 m/y and −0.54 m/y respectively, highlighting the great relevance of ongoing erosion processes. The data acquired on the shoreline evolution and current coastal dynamics of the study area provide a solid knowledge base for coastal management by the competent municipalities and regions. They also suggest the opportunity to further investigate several aspects, such as the relationships between coastal dynamics and the watersheds that feed the study coast, the effectiveness of defence structures, and the current vulnerability of the entire physiographic unit to coastal erosion.