Sandy coastlines and dune ecosystems are fragile environments currently exposed to several pressures and particularly threatened at a global, European and national scale (Acosta et al. 2009; Feola et al. 2011; Prisco et al. 2013; Genovesi et al. 2014; Janssen et al. 2016; Gigante et al. 2018). Although the degradation and loss of dune systems affect many countries all over the world, it is particularly intense along the Mediterranean coasts.

The Mediterranean basin is one of the world biodiversity hotspots (Myers et al. 2000), but, at the same time, it is one of the regions of the world subjected to the highest level of historical anthropic pressure (Newton et al. 2012; Anthony 2014). Indeed, more than 450 million inhabitants currently live in the Mediterranean countries, and especially near the coasts (UNEP/MAP 2012). The high population density along the Mediterranean shorelines represents a major threat to coastal sand dunes, which suffer from unregulated urbanization, intensive farming, infrastructures, massive bathing tourism, pollution, biological invasions and over-exploitation of the natural resources (Buffa et al. 2007, 2012; Malavasi et al. 2013, 2016; Basnou et al. 2015; Del Vecchio et al. 2015; Sciandrello et al. 2015; Poeta et al. 2017; Nordhaus et al. 2018; Sperandii et al. 2018; Giulio et al. 2020). In Italy, previous studies reported that coastal sand dunes are among the habitats with the worst conservation status, therefore, the unique biodiversity heritage along the Italian coasts needs to be preserved for the future generations and its protection should represent a priority both at national and European level.

In the last years, we have witnessed a growing global awareness concerning habitat monitoring and conservation; habitats as a whole are probably more useful indicators of ecosystem functioning compared to individual species (Balmford et al. 2002; Cowling et al. 2004; Bunce et al. 2013; Gigante et al. 2016a). The protection of biodiversity requires a constant and rigorous technical-scientific commitment at national level, which should also be extended to the obligations deriving from community rules. In particular, the Habitats Directive (92/43/EEC) requires the Member States to implement surveillance on the conservation status of habitats and species of Community Interest, taking into account also the most important threat factors that influence their future prospects (Angelini et al. 2016; Gigante et al. 2016b).

In 2016, the first European Red List of Habitats had been published. Traditionally, the Red Lists, based on criteria developed by the International Union for Conservation of Nature (IUCN), have always focused on single species with extinction risk and trends evaluated at the taxa level. The European Red List of Habitats represents a step further since plant communities and habitats have been taken into account as assessment units. This Red List confirms not only the key role of habitats concerning the implementation of conservation strategies and priorities, but also the necessity of monitoring at the ecosystem level (Rodwell et al. 2013; Keith et al. 2013, 2017; Janssen et al. 2016; IUCN 2016; Gigante et al. 2018).

Monitoring and reporting are of strategic importance to determine the effectiveness of the implementation of the Community Directives on biodiversity. Moreover, they serve as a reference framework to identify priorities and critical issues for the next monitoring period (Genovesi et al. 2014).

In this frame, based on the European guidelines (Evans and Arvela 2011), a technical manual for habitat monitoring has been produced at the national level in Italy. This manual provides practical standardised monitoring tools particularly tuned to the Italian ecological and biogeographical characteristics and peculiarities, standing as an official reference for fulfilling the monitoring obligations imposed by the Habitats Directive (Angelini et al. 2016; Gigante et al. 2016b). Major goals of the Habitats Directive are achieved through the technical reports on the conservation status of Habitats listed in Annex I (Dir. 92/43/EEC) and on conservation measures implemented in accordance with article 17. Reporting is requested every six years to each Member States and in 2019 Italy, just like the other EU27 countries, has delivered its 4th National Report referred to the period 2013-2018. The here collected and processed information represents the most updated picture of the conservation status of habitats and species of Community Interest in the whole Italian territory. The complete set of rough data is available on the Eionet Central Data Repository (2018).

The activities for the preparation of the 4th National Report have been coordinated by the Italian Institute for Environmental Protection and Research (ISPRA) on behalf of the Ministry for Environment, Land and Sea Protection (MATTM), with the scientific support of the Italian Botanical Society (SBI) and the Italian Society of Vegetation Science (SISV). Between October 2018 and May 2019, a comprehensive Working Group of territorial experts distributed by administrative regions and macro-habitat categories, worked in synergy with ISPRA itself and, where possible, with regional administrations, in order to collect, analyse and validate all the available data concerning the 124 types of terrestrial and inland water Habitats present in Italy (Gigante et al. 2019). Through a complex and multi-level teamwork and by comparing the results of the previous reporting period (2007-2012), it was possible to assess the current conservation status of each habitat at biogeographical scale and therefore to fill out the standard European assessment sheets.

As part of the results achieved by the Working Group, this paper aims at presenting the major results of the 4th National Habitat reporting for the macro-habitat type “Coastal Sand Dunes and Inland Dunes”. Specifically, we reported the updated conservation status of each coastal dune habitat at national level with reference to Biogeographical Regions.

The macro-habitat type “Coastal Sand Dunes and Inland Dunes” encompasses 21 Annex I Habitats in Europe, 11 of which have been reported in Italy. Out of these 11 habitats, 10 are coastal habitats occurring in the Continental and Mediterranean Biogeographical Regions, while only the inland dunes (Habitat 2330) is a non-coastal habitat occurring in the Continental and (marginally) Alpine Biogeographical Region (Table 1). The reporting activities led to the compilation of 19 assessment sheets, with the new inclusion of two marginal types which had not been evaluated in the 3rd Report due to a lack of robust data at that time (Genovesi et al. 2014). Among the 19 assessment sheets, one pertained to the Alpine Region, 10 to the Continental Region and 8 to the Mediterranean Region (Table 1).

The valuable ecological diversity and the multiple ecosystem services associated to dune habitats have been progressively threatened by the expansion of anthropic activities and also by natural factors, making coastal dunes among the most threatened ecosystems at the global and local scale (Schlacher et al. 2007; Defeo et al. 2009; Prisco et al. 2015, 2016a; Acosta and Ercole 2015; Sciandrello et al. 2015; Janssen et al. 2016; Malavasi et al. 2016; Marcenò et al. 2018; Sarmati et al. 2019; Carranza et al. 2020). Although the Italian shoreline still hosts several of well-preserved stretches of sandy dunes, the 4th monitoring Report just completed has clearly highlighted the alarming bad or inadequate conservation status of most dune habitats in Italy.

One of the greatest threats is related to their limited geographical extent which, with a continuously decreasing trend over the years, will lead to an increasingly worse future scenario. The most affected Habitats are those with the minimum extension, which are mainly concentrated in the Continental Region, but also in the Mediterranean one (shifting dunes, fixed dunes, dunes with Hippophae rhamnoides, dune grasslands, dunes with Juniperus species, maquis with sclerophyllous scrubs, inland dunes). Moreover, our results showed that both herbaceous and wooded Habitats are highly threatened. In particular, we should highlight the worrying conservation state of some relevant dune Habitats (e.g. Shifting dunes with Ammophila arenaria, Habitat 2120) considered with a key role in some ecosystem services, such as dune stability enhancement, coastal erosion protection, resistance of the coastal dune pollination networks, as well as in providing habitat for coastal fauna and in supporting fungal diversity (Prisco et al. 2016b; Filesi et al. 2017; Fantinato et al. 2018; Konlechner et al. 2019; De Battisti and Griffin 2020). The Habitat 2270 (Wooded dunes with Pinus species) is the only one to show at least a favourable criterion (structure and functions); however, the overall conservation status of this habitat is still inadequate (Bonari et al. 2018). Although wooded dunes are usually found in the inner part of the coastal vegetation zonation, they are often subjected to intense silvicultural treatments and tourists trampling (Sarmati et al. 2019).

The overall worrying state of conservation of the dune systems claims for a better knowledge of pressures and threats acting on these habitats and for further monitoring plans. Without such a systematic approach, coastal dune habitats are going to face further degradation trends in both structure and functions, including also the disruption of spatial zonation of plant communities (Sarmati et al. 2019). This degradation process could finally lead to a dramatic alteration of the ecosystem services they provide (Everard et al. 2010; Barbier et al. 2011; Drius et al. 2019). Additionally, degraded dune habitats are more susceptible to biological invasions (Del Vecchio et al. 2015; Gheza et al. 2018; Giulio et al. 2020).

In dynamic and vulnerable ecosystems such as coastal dunes, successful conservation outcomes in the long-term depend on sound evaluations of the effectiveness of current management measures, supported by regular and highly frequent on-ground monitoring, both inside and outside protected sites. We believe that our results provide bases and useful insights for dune habitats protection and management, in the context of the monitoring and reporting obligations set up by the Habitats Directive.

Overall, the results of the 4th Report testify for better knowledge on the geographical distribution, quality, typical species and conservation status of the whole Italian Habitats at biogeographical scale. Therefore, we should clarify that for dune Habitats, some of the changes in distribution and trends might probably be related to the application of more accurate and updated data. However, even though the geographical distribution maps of these Habitats have been validated by a large group of experts with detailed territorial knowledge, yet the lack of information on the actual location of the Habitats outside the Natura 2000 sites has negatively influenced the quantification of the Range parameter, as well as the structure and functions parameter. Finally, it’s worth noting that the information collected has been structured to ensure the archiving and traceability of both published and unpublished literature, placing a solid base of reliable and verified data at the local scale for the next reporting cycles (Gigante et al. 2019).

According to the 4th Monitoring Report (92/43/EEC Habitats Directive) the conservation status of Italian coastal sand dunes and inland dunes Habitats is dramatically bad: the overall assessment reports 88% of Habitats in a bad conservation status and the remaining 12% in an inadequate condition. Key dune habitats, such as “Shifting dunes with Ammophila arenaria”, show a bad conservation status for all the considered criteria in both Biogeographical Regions. Main pressures and threats are the development of residential, commercial and industrial areas and the expansion of alien and ruderal species. Results show an overall worse conservation status with respect to previous national reports. Although part of these changes is probably due (but not only) to the provision of more accurate and updated data, the undoubtedly bad conservation status of these unstable but resilient Habitats should draw attention to more effective conservation measures, supported by monitoring activities, both inside and outside protected areas.

We are grateful to the whole SISV Working Group for the professionalism shown and for the dedication that everyone has put into this huge and complex work: Adorni M., Allegrezza M., Armiraglio S., Attorre F., Bagella S., Barcella M., Bazan G., Bertacchi A., Bolpagni R., Bonari G., Caccianiga M., Cacciatori C., Caria M., Casavecchia S., Cerabolini B., Ciaschetti G., Ciccarelli D., Cogoni A., Cutini M., De Sanctis M., De Simone W., Del Vecchio S., Di Cecco V., Di Martino L., Di Musciano M., Fantinato E., Ferella G., Filesi L., Foggi B., Forte L., Frattaroli A., Galdenzi D., Gangale C., Gennai M., Gianguzzi L., Giusso Del Galdo G., Guarino R., Lasen C., Maneli F., Mariotti M., Oriolo G., Paura B., Perrino E., Pesaresi S., Pezzi G., Pisanu S., Poponessi S., Puglisi M., Rivieccio G., Selvaggi A., Siniscalco C., Spampinato G., Stinca A., Strumia S., Taffetani F., Tesei G., Tomaselli V., Venanzoni R., Viciani D., Wagensommer R. and Zanatta K.

We also would like to thank Pierangela Angelini and Laura Casella, from ISPRA, for being an important point of reference.

Alicia T.R. Acosta gratefully acknowledges the Grant of Excellence Departments, MIUR-Italy (ARTICOLO 1, COMMI 314 – 337 LEGGE 232/2016).