Ten years of vegetation recovery following Nature-based restoration of landslide scars in the Azores

Landslides are common in the Azores due to steep topography, volcanic soils, and high rainfall, creating disturbed areas that are often colonized by invasive plant species and contribute to habitat degradation within the Pico da Vara/Ribeira do Guilherme Special Protection Area (São Miguel Island). In 2015, as part of the LIFE+ Lands of Priolo project, Nature-based Solutions (NbS) combining bioengineering measures and hydroseeding with native species were implemented to restore five landslide scars. This study evaluates vegetation recovery over a ten-year period. Hydroseeding species accounted for 82.5% of total germination, although establishment success varied substantially among taxa. After ten years, restored slopes were dominated by native vegetation, with a mean native cover of 87.9%, while exotic species richness and cover were significantly lower than in control areas. Only Calluna vulgaris and Festuca francoi remained abundant among the hydroseeded species, whereas Sphagnum sp. and Woodwardia radicans became dominant through natural colonization. Multivariate analyses revealed significant differences in plant community composition between restored and control slopes. The results suggest that long-term vegetation recovery resulted from the combined effects of active restoration measures and natural ecological succession. This study provides rare long-term evidence of NbS performance in a protected island area and highlights their potential to support habitat restoration following landslide disturbance.