Mediterranean developed coasts: what future for the foredune restoration?

Abstract

The feasibility and efficacy of soft engineering foredune restoration approaches still lack insight from research and monitoring activities, especially in areas where dunes are under persisting human disturbance. We evaluated the efficacy of Mediterranean foredune restoration in dune areas freely accessible to tourists. Foredunes were reconstructed using only sand already available at nearby places and consolidated through the plantation of seedlings of native ecosystem engineer species and foredune focal species. We monitored transplanted and spontaneous seedlings for one year to assess their mortality and growth in relation to the distance from the closest beach access, either formal or informal, as proxy of human disturbance. We also tested whether species differing in their ecology (i.e., affinity to a given habitat) and growth form showed different response to human disturbance. The relationship between seedling mortality and growth and the distance from the closest beach access was tested through Generalized Linear Mixed Models. We found a clear spatial pattern of seedling survival and growth, which decreased as the proximity to the closest beach access increased. Only invasive alien plants and erect leafy species showed to better perform at lower distances from beach accesses. In dune areas with a strong tourist vocation, foredune restoration should be coupled with the implementation of integrated management plans aiming at optimising the relationship between protection and use. Management plans should not only rely on passive conservation measures; rather they should include educational activities to stimulate a pro-environmental behaviour, increase the acceptance of behaviour rules and no entry zones, and actively engage stakeholders in long-term conservation.

The Green Infrastructure of Sandy Coastlines: A Nature-Based Solution for Mitigation of Climate Change Risks

“…All coastal landforms exhibit natural morphodynamic variability, but appropriate soft engineering strategies can enhance coastal landform and ecosystem properties and thereby result in greater resilience [11,15,62]. These strategies focus on building and stabilizing landform surfaces by increasing their volume or height or by revegetation [63][64][65]. In so doing, these landforms and ecosystems can be considered as 'green infrastructure', serving the same function as hard engineering structures traditionally used for coastal management and protection [64,[66][67][68].…”

Dune belt restoration effectiveness assessed by UAV topographic surveys (Northern Adriatic coast, Italy)

“…Human disturbances by mass tourism and coastal urbanization put detrimental impact on pioneer vegetation species and can prejudice the sustainability of foredune restoration especially in the Mediterranean (Della Bella et al, 2021). The fence has halted human trampling on dune vegetation that had limited the formation of erosional features such as blowouts.…”

Using functional traits and species diversity to evaluate restoration success of coastal dunes

“…Despite numerous projects around the world, few long-term studies have evaluated the success of dune habitat restoration, particular their biodiversity value (Lithgow et al, 2013;Della Bella et al, 2021).…”

“…These restoration projects usually involve the re‐accumulation of sand through the installation of passive sand‐trapping systems, and often also include plantations of species known as “dune builders” (i.e., Ammophila arenaria , A. breviligulata , Elymus farctus and Panicum amarum depending on the region considered; Fischman et al, 2019). Despite numerous projects around the world, few long‐term studies have evaluated the success of dune habitat restoration, particular their biodiversity value (Lithgow et al, 2013; Della Bella et al, 2021).…”