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Understanding drivers of success for alien species can inform on potential future invasions. Recent conceptual advances highlight that species may achieve invasiveness via performance along at least three distinct dimensions: 1) local abundance, 2) geographic range size, and 3) habitat breadth in naturalized distributions. Associations among these dimensions and the factors that determine success in each have yet to be assessed at large geographic scales. Here, we combine data from over one million vegetation plots covering the extent of Europe and its habitat diversity with databases on species’ distributions, traits, and historical origins to provide a comprehensive assessment of invasiveness dimensions for the European alien seed plant flora. Invasiveness dimensions are linked in alien distributions, leading to a continuum from overall poor invaders to super invaders—abundant, widespread aliens that invade diverse habitats. This pattern echoes relationships among analogous dimensions measured for native European species. Success along invasiveness dimensions was associated with details of alien species’ introduction histories: earlier introduction dates were positively associated with all three dimensions, and consistent with theory-based expectations, species originating from other continents, particularly acquisitive growth strategists, were among the most successful invaders in Europe. Despite general correlations among invasiveness dimensions, we identified habitats and traits associated with atypical patterns of success in only one or two dimensions—for example, the role of disturbed habitats in facilitating widespread specialists. We conclude that considering invasiveness within a multidimensional framework can provide insights into invasion processes while also informing general understanding of the dynamics of species distributions.

In mountainous regions, climate warming is expected to shift species' ranges to higher altitudes. Evidence for such shifts is still mostly from revisitations of historical sites. We present recent (2001 to 2008) changes in vascular plant species richness observed in a standardized monitoring network across Europe's major mountain ranges. Species have moved upslope on average. However, these shifts had opposite effects on the summit floras' spedes richness in boreal-temperate mountain regions (+3.9 species on average) and Mediterranean mountain regions (-1.4 species), probably because recent climatic trends have decreased the availability of water in the European south. Because Mediterranean mountains are particularly rich in endemic species, a continuation of these trends might shrink the European mountain flora, despite an average increase in summit species richness across the region.

Several regulatory and management tools are commonly used to prevent negative effects of human trampling on sand dune habitats, but few studies have attempted to evaluate the effects of boardwalks on dune vegetation. We aimed to evaluate changes of species richness and cover, floristic composition and ecological functional guilds among different dune habitats 2 years after the boardwalks had been established, highlighting those habitats mainly affected by these changes. In a Special Protection Area of Molise region (Italy), we sampled 53 square plots before the installation of five wooden boardwalks (control plots) and 57 plots after the boardwalks had been set up (testing plot), across the whole dune system ranging from the upper beach to the pine forest. We compared species richness through rarefaction curves, considering two plant functional groups: focal species (characteristic and diagnostic) and ruderal/exotic species. We finally compared florist composition and cover changes between time intervals, dune habitats and functional groups. In all habitats the total plant richness of testing plots was higher than in the control plots. In beach and mobile dunes habitat focal species drive the increase in both species’richness and cover. Dune grasslands proved to be the most affected by the presence of ruderal and exotic species, while the more stable fixed dunes habitat was less affected by species changes. Only 2 years after the boardwalks having been set up, we have found a rapid recovery since human trampling was limited. The use of boardwalks could be an effective tool for reducing negative impact of bathing tourism on coastal dunes and requires little and inexpensive maintenance.

Focusing on mountain plant communities across Europe, a study shows that ongoing climate change causes a gradual decline in cold-adapted species and a corresponding increase in warm-adapted species, which could be an early sign that mountain plant diversity is at risk. Climate impact studies have indicated ecological fingerprints of recent global warming across a wide range of habitats 1 , 2 . Although these studies have shown responses from various local case studies, a coherent large-scale account on temperature-driven changes of biotic communities has been lacking 3 , 4 . Here we use 867 vegetation samples above the treeline from 60 summit sites in all major European mountain systems to show that ongoing climate change gradually transforms mountain plant communities. We provide evidence that the more cold-adapted species decline and the more warm-adapted species increase, a process described here as thermophilization. At the scale of individual mountains this general trend may not be apparent, but at the larger, continental scale we observed a significantly higher abundance of thermophilic species in 2008, compared with 2001. Thermophilization of mountain plant communities mirrors the degree of recent warming and is more pronounced in areas where the temperature increase has been higher. In view of the projected climate change 5 , 6 the observed transformation suggests a progressive decline of cold mountain habitats and their biota.

Ecological theory predicts close relationships between macroclimate and functional traits. Yet, global climatic gradients correlate only weakly with the trait composition of local plant communities, suggesting that important factors have been ignored. Here, we investigate the consistency of climate-trait relationships for plant communities in European habitats. Assuming that local factors are better accounted for in more narrowly defined habitats, we assigned > 300,000 vegetation plots to hierarchically classified habitats and modelled the effects of climate on the community-weighted means of four key functional traits using generalized additive models. We found that the predictive power of climate increased from broadly to narrowly defined habitats for specific leaf area and root length, but not for plant height and seed mass. Although macroclimate generally predicted the distribution of all traits, its effects varied, with habitat-specificity increasing toward more narrowly defined habitats. We conclude that macroclimate is an important determinant of terrestrial plant communities, but future predictions of climatic effects must consider how habitats are defined. Climatic variables are useful but often weak predictors of plant functional trait variation across ecosystems. Here the authors investigate how assigning plant communities to a habitat hierarchy improves the explanatory power of climate-trait relationships at the continental scale.

Coastal areas are biodiversity hotspots, providing essential ecosystem services, yet they are among the most threatened systems, particularly by alien species invasion. The European regulation on invasive alien species (IAS) highlights early detection as a key prerequisite for effective containment or eradication strategies. Traditional monitoring methods are costly and time-consuming, and Citizen Science (CS) may be a promising alternative. We assessed the contribution of the generalist CS project “Wild Coast Adriatic” (WCA) developed on the iNaturalist platform to the detection of alien species (AS) along the Central Adriatic coast. Using WCA, we extracted alien occurrences and explored AS seasonal patterns, geographic origins, dangers (EU regulation), and distributions inside protected areas (Natura 2000 and LTER sites). Between 2020 and 2023, WCA gathered 2194 research-grade observations of 687 species, including 139 records of 50 AS, five of which are of European concern. Asteraceae and Fabaceae (plants) as well as insects and mollusks (fauna) were the most abundant aliens. The observations increased over time, with more records concentrated in autumn and summer. Most AS come from the Americas and occurred outside the protected areas. Our results underline the contribution of CS data for detecting AS in coastal ecosystems, offering a valid support for early warning, monitoring, and management strategies.

We analyzed plant functional diversity (FD) and redundancy (FR) in Mediterranean high-mountain communities to explore plant functional patterns and assembly rules. We focused on three above-ground plant traits: plant height (H), a good surrogate of competition for light strategies, and specific leaf area (SLA) and leaf dry matter content (LDMC), useful indicators of resource exploitation functional schemes. We used the georeferenced vegetation plots and field-measured plant functional traits of four widely spread vegetation types growing on screes, steep slopes, snowbeds and ridges, respectively. We calculated Rao’s FD and FR followed by analysis of standardized effect size, and compared FD and FR community values using ANOVA and the Tukey post hoc test. Assemblage rules varied across plant communities and traits. The High FRH registered on snowbeds and ridges is probably linked to climatic filtering processes, while the high FDH and low FDSLA and FDLDMC on steep slopes could be related with underlying competition mechanisms. The absence of FD patterns in scree vegetation pinpoint random assembly processes which are typical of highly unstable or disturbed ecosystems. Improved knowledge about the deterministic/stochastic processes shaping species coexistence on high mountain ecosystems should help researchers to understand and predict vegetation vulnerability to environmental changes.

Global change threatens alpine biodiversity and its effects vary across habitat types and biogeographic regions. We explored vegetation changes over the last 20 years on two Mediterranean alpine calcareous grasslands in central Apennines (Italy): stripped grasslands (EUNIS code E4.436) with Sesleria juncifolia growing on steep slopes, and wind edge swards (EUNIS code E4.42) with Carex myosuroides. Based on a re-visitation of 25 vegetation plots of 4 × 4 m, we assessed changes in overall and endemic plant species cover and richness by nonparametric Kruskal–Wallis test. We explored changes in structure and ecology using growth forms and Landolt indicators for temperatures. We identified species’ contribution to temporal changes using the similarity percentage procedure (SIMPER). The results evidenced a significant decline in all species cover and richness on both plant communities with a significant decline in alpine and endemic species and in hemicryptophytes with rosette and scapose ones on stripped grasslands, as well as a decline in subalpine and suffruticose chamaephytes species on wind edge swards. Such biodiversity loss, so far observed only in the warmest and Southern Mediterranean summits of Europe, is likely attributable to the combined effect of higher temperatures; the increase in the vegetative period; and the decrease in water availability, which is particularly severe in calcareous regions. Our study suggested the vulnerability of the analyzed alpine ecosystems to global change and the importance of monitoring activities to better understand vegetation trends and adaptation strategies in subalpine, alpine, and nival ecosystems.

Invasive alien plants (IAP) pose a major threat to biodiversity and have a negative impact on the integrity and conservation status of plant communities. Mediterranean dunes are widely exposed to IAP, due to their environmental heterogeneity and the anthropogenic pressures to which they are subjected. The current study explored the possible existence of critical thresholds of IAP cover/abundance and dune path impacts that may cause the decline in diagnostic species cover in shifting and transition dunes. A random sampling of 126 plots in areas invaded and not invaded by IAP across the Italian Adriatic dunes has been used and the recorded species have been classified in ecological guilds. In order to explore the effect of plant community composition and distances from dune paths on the diagnostic species cover, a Random Forest regression model has been fitted. The results revealed that three main critical thresholds can be detected concerning IAP total cover, IAP Oenothera stucchii Soldano abundance and the distance from dune paths and they work differently in shifting and transition dunes. The identification of such cut-off points provides useful insights for an array of actions to preserve the biodiversity of the Mediterranean coastal dunes.

The landscape has always been a fundamental factor in defining tourist flow attraction for local development. In this paper, landscape related to tourism have been analysed using three different measurements through appropriate performance indicators and rationalised with the aim of identifying a scheme of mutual relations. Applying advanced statistical methods of ranking and data synthesis, the area investigated (Molise, Italy) has been divided into different zones. Each area described has a specific relation between tourism and landscape useful in the implementation of optimal promotion strategies and valorisation of the area. In marginal areas, tourism can have an excellent growth potential, since they are characterized by the high quality of the landscape. However, the analysis highlights some gap areas, which means the existence of areas with high quality of the natural and agricultural landscape is not associated with an appropriate tourism development, or areas where the high tourism development is not associated with an appreciable quality of the landscape.