Monitoring and assessing the conservation status of dune habitat types by standardized protocols and integrated approaches: a case study in southern Italy.

General frameworks At a European level, coastal dune systems host a large variety of habitat types of community interest according to the 92/43 EEC Habitat Directive. Among them, the priority habitat 2250*-“Coastal dunes with Juniperus spp. has been assessed as 'unfavorable-bad' in the whole Mediterranean biogeographic region (https://nature-art17.eionet.europa.eu/). In this scenario, continuative and consistent monitoring programs are fundamental for implementing effective management policies (Ellwanger et al., 2018). Remote sensing techniques represent a valuable addition to field-based approaches in vegetation science, allowing vegetation and habitats to be mapped as a continuum in space and time (Delbosc et al., 2020, Lahoz-Monfort & Magrath, 2021). Objectives We addressed our study to a Natura 2000 site in Calabria region (southern Italy), namely IT9320102 – “Dune di Sovereto”. It is characterized by an extensive coastal dune system hosting many different habitat types under the 92/43 EEC Directive. Among them, the priority habitat type 2250* is present with centuriesold juniper shrubs, even though subject to severe threats and pressures. Monitoring procedures applied both field surveys and remote sensing techniques. They focused mainly on habitat 2250* but, considering the landscape complexity, the adjacent habitat types were included in the analysis. Field work involved the execution of vegetation survey by random plots and belt transects, according to the Italian Manual for the Monitoring of species and habitats of community interest (Angelini et al., 2016), with the systematic recording of pressures and threats. Moreover, the detection of typical, alien, and other indicator species, allowed the assessment of the habitat conservation status, also by the introduction of some synthetic indexes. The remote sensing approach followed different strategies, from the simple visual interpretation of aerial multi-temporal orthophotos, to the acquisition of very high-resolution images by UAS for the finest detections, up to the classification of Very High Resolution (VHR) satellite images by a Knowledge-Driven Object-based (KDOB) approach. Finally, a set of Landscape Metrics (LMs), specifically selected for coastal habitats, was applied to the produced habitat and vegetation maps, to evaluate composition and configuration at both landscape and habitat level, and assess integrity of spatial patterns. Main findings, results, and indications of the proposed work Habitat 2250* was successfully characterized and spatially delineated. KDOB procedures yielded highly promising results, confirming their potential for automated and repeatable habitat mapping within complex Mediterranean dune systems. Landscape metrics revealed a markedly fragmented and spatially scattered configuration, indicative of ongoing degradation processes. The integration of field survey data and quantitative analyses enabled the assessment of conservation status at a fine ecological scale. Overall, the habitat exhibited poor conservation conditions, primarily due to recurrent wildfires and the widespread presence of invasive alien species, which display strong competitive advantages and threaten the persistence of native dune vegetation.