Combining field collected and remotely sensed (RS) data represents one of the most promising approaches for an extensive and up-to-date ecosystem assessment. We investigated the potential of the so called spectral variability hypothesis (SVH) in linking field-collected and remote-sensed data in Mediterranean coastal dunes and explored if spectral diversity provides reliable information to monitor floristic diversity, as well as the consistency of such information in altered ecosystems due to plant invasions. We analyzed alpha diversity and beta diversity, integrating floristic field and Remote-Sensing PlanetScope data in the Tyrrhenian coast (Central Italy). We explored the relationship among alpha field diversity (species richness, Shannon index, inverse Simpson index) and spectral variability (distance from the spectral centroid index) through linear regressions. For beta diversity, we implemented a distance decay model (DDM) relating field pairwise (Jaccard similarities index, Bray–Curtis similarities index) and spectral pairwise (Euclidean distance) measures. We observed a positive relationship between alpha diversity and spectral heterogeneity with richness reporting the higher R score. As for DDM, we found a significant relationship between Bray–Curtis floristic similarity and Euclidean spectral distance. We provided a first assessment of the relationship between floristic and spectral RS diversity in Mediterranean coastal dune habitats (i.e., natural or invaded). SVH provided evidence about the potential of RS for estimating diversity in complex and dynamic landscapes.

Alien plants represent a significant threat to species diversity and composition in natural habitats. Nevertheless, little is known about the dynamic of the invasion process and how its effects on native species change over time. In this study, we explored vegetation changes that occurred in invaded coastal dune habitats over the last 10–15 years (2005–2020), particularly addressing impacts on alien and diagnostic species. To monitor temporal trends, we used data resulting from a revisitation study. After detecting overall changes in alien species occurrence and cover over time, 127 total plots were grouped into plots experiencing colonization, loss, or persistence of alien species. For these three categories, we compared historical and resurveyed plots to quantify changes in native species composition (using the Jaccard dissimilarity index) and to measure variations in diagnostic species cover. The number of alien species doubled over time (from 6 to 12) and two species, Yucca gloriosa and Agave americana, strongly increased their cover (+5.3% and +11.4%, respectively). Furthermore, plots newly invaded appeared to record the greatest changes in both native and diagnostic species. Our results suggest the need for regular monitoring actions to better understand invasion processes over time and to implement effective management strategies in invaded coastal dune habitats.

Coastal dunes are uniquely dynamic environments continuously shaped by a complex network of physical and biotic factors. Due to its location, the northwest of Ireland presents a challenging coastline characterised by high waves and wind energy. Even though dune systems in this area are frequently subject to habitat loss and erosion processes, comprehensive ecological studies are scarce. With the primary objective of investigating species composition and morphometric variability, we selected 13 dune sites and collected 409 vegetation plots and multiple cross-shore profiles. We implemented multivariate analyses to detect the main patterns in vegetation and geomorphology, and functional traits (TRY database) to evaluate plant strategies along the natural gradient. We observed high geomorphological heterogeneity across the beach–dune area. The PCA results were linked to the width of the natural system and to erosion or progradation trend. Different habitats of conservation interest were identified, and the environmental gradient proved to be the primary influence on species composition. In addition, different patterns in functional traits were detected along the zonation in response to the intensity of abiotic factors. The application of a multidisciplinary approach was crucial in unravelling the complexity of these environments and highlighting the need for context-specific conservation strategies.

Coastal dune environments are vulnerable systems threatened by a complex network of physical, biotic and anthropic pressures. Even though they host high biodiversity, dune habitats are deteriorating and disappearing, causing the loss of their protective role against climate hazards. Finding a repeatable methodology to assess the ecological condition of these ecosystems is important to support decision-making and preserve dune resilience. Vulnerability indices are frequently implemented to simplify the variables influencing the coastline; nonetheless, their structure varies according to the scale and the objective(s) of the study. We selected 13 sites in the Northwest of Ireland and tested a new Coastal Dune Assessment Tool, inspired by pre-existing indices. The main objective was to build a multidisciplinary index, based exclusively on quantitative indicators, able to score ecological condition at a local scale and prioritise sites in need of management actions. We implemented cluster and multivariate analysis to group sites with similar status and pressures and compared the results with a quali-quantitative index. The physical indicators presented the highest scores, and the morphology of the dune system, the presence of artificial structures and grazing played an important role in the classification. The index enabled comparisons between sites and provided useful information that could be used to select the most appropriate intervention strategies, such as determining the necessity of restoration or preservation actions. Management is often a challenging process in dynamic environments, and adapting monitoring strategies able to convey a flexible but reliable methodology is a crucial step in conservation.