Mediterranean wetlands are highly sensitive ecosystems, particularly vulnerable to human pressure and shifts in precipitation and temperature regimes. Wetland plants can be particularly threatened in Mediterranean insular contexts, where such habitats are naturally smaller and more fragmented than in their continental counterparts. This study investigated 275 species of vascular wetland plants that were considered to be at least regionally threatened across 2217 islands and islets in the Mediterranean. We provided both global and local IUCN conservation assessments (summarized in a ‘conservation concern’ index) and ‘assessment completion’ (i.e. knowledge level) for each taxon as well as a geographic distribution among islands, wetland types, and life forms. Most of wetland plants were threatened at the regional level, although assessment completion was generally low, except for endemics. Inland and endemic wetland plants were more threatened than the rest. A phylogenetic signal was detected, highlighting that Orchidaceae and Apiaceae were of particularly high conservation concern, while other families, especially Amaranthaceae, exhibited low levels of assessment completion. No geographical patterns were found in terms of conservation concern and assessment completion. Our findings provide critical insights into biodiversity patterns, identify conservation gaps and priorities and contribute to the development of targeted strategies for the protection of wetland plants, which are crucial indicators of the entire natural capital of Mediterranean island ecosystems.

Most proposals relating to the biogeographic regionalization of Algeria have been made by traditional qualitative method (geography, geology, climatology, vascular flora), on the basis of expert’s opinions. A new biogeographic regionalization of Algeria is herein proposed, based on quantitative approach and using objective multivariate methods. Bio-geoclimatic datasets were analysed using cluster analysis techniques to define biogeographical units. A georeferenced floristic database for Algerian strict-endemic plants was compiled, including distribution information from different sources, to characterise the indicator species of these units. Our new proposal for Algeria encompasses 28 biogeographical units recognised within the country that reflect specific regional topography and ecoclimatic conditions. Eight distinct and spatially coherent sectors were identified, and 20 nested districts were detected, based on biogeographical features. All of these biogeographical units are listed and their position and boundaries are mapped. The main predictive environmental descriptors of the sectors were Thornthwaite aridity index, elevation, Min Temperature of Coldest Month (Bio6), Precipitation of Warmest Quarter (Bio18), Coefficient of variation of Enhanced Vegetation Index (EVI), Evenness of EVI, and soil organic carbon. We highlighted the endemic plants that define the districts, using the indicator species criterium. The use of a large dataset of environmental factors and endemic plant species, coupled with numerical analyses, makes this study novel and allows an enhanced bioregionalization system for Algeria. We provide a reliable sectorisation for use in conservation planning, biodiversity assessment, or climate change studies.

Taxonomic assignments based only on morphology are often insufficient for delimiting species, particularly in polyploid complexes with extensive morphological overlap. This limitation hinders biogeographic and conservation issues. The genus Romulea (Iridaceae), distributed across Africa and the Mediterranean Basin, exemplifies this challenge. Despite its remarkable diversity, Mediterranean Romulea has remained largely understudied at the molecular level. Here, we present the first multilocus genotype analysis of several taxa of the Mediterranean region, with a sampling focused on the Tyrrhenian biogeographic province. Using the hybseq method with the universal Angiosperms353 target capture kit, we sequence nuclear (on target) and plastid loci (off target) for 272 individuals representing 18 putative taxa. Nuclear SNP genotyping yield 8,168 high-confidence loci, revealing 19 genetic groups. Hind/HE analyses indicate a predominance of allopolyploid inheritance. Analyses of genetic diversity reveal incomplete differentiation, introgression, or plastid capture, which complicate species delimitation. Several taxa, including R. x melitensis, R. corsica, and R. bulbocodium, show genomic signatures consistent with hybrid origins. Four taxa (R. assumptionis, R. revelieri, R. ligustica, R. rollii) are consistently well differentiated across nuclear and plastid datasets, supporting their recognition as distinct species. The widespread species R. ramiflora and R. columnae contain well-differentiated groups that are either isolated or close to other taxa, calling for further analysis to differentiate cryptic speciation from historical introgression. Our findings question the current taxonomic status of several narrow endemic species. Based on robust genetic boundaries, we propose various solutions for further taxonomic studies. The plastid phylogeny reveals a star-like diversification pattern, consistent with rapid radiation in the Tyrrhenian region. These results provide a primary genomic framework for integrative taxonomy in Romulea, highlighting the central role of polyploidy and reticulate evolution in shaping Mediterranean diversity and offering key insights for biogeography, systematics and conservation.

A comprehensive analysis of published records of terrestrial vascular plants reported from the Comino archipelago (Maltese Islands) since the mid-1800s and of plants recorded by us between 2008 and 2025 was combined to synthesise the first annotated and comprehensive checklist of vascular plants of Comino. A total of 328 observations were made, of which 78 are new records for Comino and two are recorded for the first time in the Maltese Islands. The flora consists of 490 vascular plant species. This study identifies and examines ecologically sensitive species on the Comino archipelago, including 58 strictly and legally protected species, 21 endemics, and several other plants that are red-listed as threatened species or are very rare in the Maltese Islands (e.g., Euphorbia peplis, Hornungia procumbens, and Malva setigera). Alien species are also reviewed, and 12 out of the 61 recorded species are declared invasive for Malta, but only a few are effectively invasive on Comino (e.g., Acacia saligna, Ailanthus altissima, and Oxalis pes-caprae). In addition, this account offers a concise yet comprehensive overview of Comino’s geology, natural habitats, climate, and anthropogenic history. More critically, it identifies the principal threats and pressures affecting the island, which have contributed, at least in part, to the disappearance of approximately 160 species previously recorded but not observed for several decades. As highlighted in previous studies, the persistent issue of over-tourism on Comino over the past 15–20 years warrants urgent attention, as the most recent reports indicate that some 10,000 visitors flock to the small beaches of the Blue Lagoon and Santa Marija Bay, which, as also demonstrated in this report, overwhelm and disturb this ecologically sensitive Natura 2000 archipelago.

Large-scale biodiversity databases encompass three main types of data for plants, namely single species point occurrences, co-occurrences in vegetation plots, and checklists for specific areas. Evidence shows that such data types exhibit specific biases, reporting different species assemblages at local scales. We used the Mediterranean Basin, a global biodiversity hotspot with more than 2200 islands larger than 0.01 km2, to compare island vascular plant diversity patterns emerging from occurrence data (Global Biodiversity Information Facility; GBIF), vegetation plots (European Vegetation Archive; EVA), and species checklists (Global Inventory of Flora and Traits; GIFT). We aggregated plant data at the island level and compared geographic coverage, inventory completeness, and taxonomic coverage among these data sources. The combined databases accounted for 8702 species distributed on 790 islands (35.6% of the target islands). Data availability increased from small (26.8%) over medium (75.7%) to large islands (100.0%). Spatial coverage of databases on a 30 & times; 30 km grid was high for GBIF (52.8%) and EVA (45.4%), and low for GIFT (21.7%). GIFT provided higher native and alien species richness values for most of the islands, whereas GBIF and EVA consistently missed a considerable fraction of the expected species richness. Taking GIFT as reference, GBIF, and to a lesser extent EVA, showed a positive bias towards perennial species and an underrepresentation of annuals. Despite their lower taxonomic coverage, GBIF and EVA data can complement our knowledge on Mediterranean islands' plant diversity, providing data for islands lacking plant inventories. Moreover, GBIF and EVA's large datasets can be used for investigating other levels of ecological organisation and modelling single species (GBIF) or population (EVA) trends over space and time. Finally, our results advocate for a coordinated effort to fill the knowledge gaps through data collection and digitisation, possibly integrating data collected by experts by means of citizen science initiatives.

Studying climate at fine spatial scales reveals critical differences between regional and local conditions. Quantifying and understanding the drivers of microclimate is essential for assessing climate change impacts. Microclimates can be colder or warmer than the macroclimate (i.e. buffering effect); but they can also deviate from macroclimatic trends, a phenomenon termed decoupling. We quantify spatial variations in both buffering and decoupling effects in a rugged Mediterranean landscape in south-eastern France in response to heterogeneous topography and vegetation structure. Based on 15 months of data, collected from a network of 60 microclimatic sensors deployed across 30 ha, we highlight fine scale spatial mosaics of contrasting buffering and decoupling effects that vary seasonally and depend on the microclimatic variable considered: maximum temperature (Tmax), vapor pressure deficit, or minimum temperature. Observations reveal large microclimatic contrasts within a few meters in terms of buffering (from -8.26°C to +10.77°C locally compared to macroclimate for Tmax in summer) and decoupling (from 0.35°C to 1.84°C increase locally for a 1°C increase in macroclimate, for Tmax in summer). Analyses further reveal that the main drivers of microclimate shift seasonally from topographic factors, particularly relative elevation and solar radiation, during the cold season, to vegetation characteristics, e.g. height, during the growing season. Although climatic conditions are often expected to vary linearly across space (e.g. cooling with altitude or latitude), heterogeneous landscapes may support mosaics of microclimates that can locally attenuate or amplify broad-scale climatic trends. However, while attenuation processes are relatively well documented in forest systems, both attenuation and amplification remain insufficiently quantified in complex terrains, limiting our ability to predict local ecosystem trajectories under climate change.

Aim Understanding the relative influence of past and present environmental and anthropogenic drivers on biodiversity is crucial for predicting future biodiversity trends. We assessed how past climate stability, present climate, habitat characteristics, disturbances (fire and herbivory), and past and present land use shape current functional and phylogenetic diversity across multiple taxa.Location Euro-Mediterranean forests.Time Period From Last Glacial Maximum to Present Day.Major Taxa Studied Trees, birds, butterflies, reptiles, and mammals.Methods We quantified standardised functional and phylogenetic diversity across three dimensions: richness, dispersion, and originality for five taxonomic groups. Focusing on 54 individual drivers, we applied random forests to evaluate the importance of broad categories of drivers and understand how individual drivers impact each diversity dimension.Results Past temperature stability since the Last Glacial Maximum emerged as a dominant driver of functional and phylogenetic diversity across taxa. Stability was associated with higher functional and phylogenetic richness and dispersion, whereas unstable past climates were linked to lower diversity. Herbivory also played a significant role, though it was less influential than the past climate, particularly for trees and reptiles, whereas the present climate influenced birds' functional diversity. Fire intensity and surface, and land use in the present and past had limited importance, likely because of the study grain resolution.Main Conclusions Our findings underscore that long-term climate conditions continue to influence biodiversity patterns across various taxa. This highlights the importance of considering both past legacies and present conditions when assessing biodiversity responses to future climate change. Lastly, we revealed dimension and taxon-specific responses to drivers, reinforcing the need for integrative biodiversity frameworks that incorporate multiple facets and dimensions of biodiversity across different taxa to get a more nuanced understanding of how biodiversity is structured and maintained.

Les colonies d’oiseaux marins nicheurs impactent la physico-chimie des sols ainsi que les communautés végétales sur les îles. Ces écosystèmes insulaires sont caractérisés par des plantes endémiques adaptées aux conditions stressantes (xéricité, salinité, sol superficiel, vent). Plusieurs études ont permis d’évaluer les effets de l’augmentation démographique d’oiseaux marins, mais peu ont réalisé un suivi sur le long terme en prenant en compte leur déclin après explosion démographique. L’objectif de la présente étude (sur 24 ans) a consisté à mesurer les changements physico-chimiques des sols, de la composition des communautés végétales en relation avec la diminution démographique des Goélands leucophées (Larus michahellis Naumann, 1840) sur les archipels insulaires du Frioul et de Riou (Marseille, France). Les enjeux conservatoires de ce contexte insulaire ont été analysés en caractérisant les types fonctionnels des plantes (formes de croissance de Raunkiaer et stratégies de vie de Grime) et en étudiant la variation des plantes à enjeu de conservation, puisque l’apport de nutriments et de polluants, tels que les éléments traces métalliques, via les goélands peut entraîner leur disparition. Pour cela, des analyses de sol (en 1997 et 2021) ainsi que des relevés floristiques (en 1997, 2008 et 2021) ont été réalisés sur 78 placettes permanentes situées sur neuf îles et sur le littoral continental du Parc national des Calanques. Depuis 1997, les teneurs en nitrogène et le pH ont augmenté, alors que le carbone organique ainsi que le rapport C/N ont diminué. En 2021, les mesures des concentrations en éléments traces révèlent des niveaux de contamination relativement faibles sur le continent et les archipels. De 2008 à 2021, les communautés végétales des îles ont été caractérisées par une augmentation du nombre de plantes rudérales. Le déclin des effectifs de Goélands leucophées n’a pas engendré de diminution des plantes tolérantes aux perturbations ni d’augmentation très significative de la flore à enjeu de conservation, mais a entraîné une augmentation des chamaephytes et du recouvrement total de la strate herbacée. Nos résultats suggèrent donc une rémanence des altérations des paramètres des sols ainsi que des communautés végétales toujours rudéralisées. Cependant, une résilience s’opère en termes de recouvrement de la strate herbacée lorsque la pression des goélands diminue.

The origin of narrow endemic plants is a long-standing issue in Mediterranean biogeography. Estimates of divergence time may provide new insights into the likely pivotal periods in the evolutionary history of narrow endemics. Here, based on transcriptomic data and benefiting from the phylogenomic data provided by the Plant and Fungal Trees of Life Project (PAFTOL), we examined the origin of the narrow endemic plant Arenaria provincialis. We used several nuclear and plastid loci to conduct divergence time analyses embracing uncertainty of node age calibrations, allowing us to provide a new time tree for the plastid lineages of this species. The results clearly support a deep divergence time within A. provincialis that likely occurred during the Pliocene. This timeline shows that the evolutionary history of A. provincialis is closely linked to the geological and climatic changes that shaped the massifs of Provence (southeast France) before the Pleistocene. Our study also illustrates the contribution of the open and comprehensive PAFTOL project to divergence time analyses.

While 38% of tree species are at risk of extinction worldwide, their inventory and occurrence at ecologically and biogeographically meaningful scales is lacking in many parts of the world, including the biodiversity-rich Mediterranean region. Here, we provide presence/absence, extinction risk, biogeography and genetic diversity data of trees in 39 climatically and ecologically Mediterranean territories (so-called “botanical territories”) in North Africa, Western Asia and Southern Europe. The inventory includes 496 species and 147 subspecies from 50 families and 111 genera, including 48 species and 8 subspecies previously not considered as trees. We show that native tree species distribution is highly skewed across the tree of life with a few species-rich families such as the Rosaceae and the majority with less than 1% of all species. Endemism was not evenly distributed among botanical territories and neither was extinction risk, an assessment of which was lacking in almost half of the species. While no geographic trends were detectable, species richness was found to be positively correlated with botanical territory area and, when standardized by area, with habitat heterogeneity. Information on genetic diversity was lacking in two thirds of the species inventoried and mostly focused on species with economic importance. Our data are open access and can be used by researchers and stakeholders for a wide range of purposes, including conservation and restoration. Our findings identified major native tree richness hotspots as well as key knowledge gaps and biases related to extinction risk and genetic diversity. Our findings also emphasize the importance of increased collaboration to support the conservation of Mediterranean forest trees.

The naturalist and explorer Jacques-Julien Houtou de La Billardi & egrave;re (1755-1834) remains known for his participation in the d'Entrecasteaux expedition (1791-1794) in charge of finding La P & eacute;rouse and its ships missing in Oceania. This long journey in the southern hemisphere allowed him to discover many new species of flora and fauna, but also to carry out many ethnological observations. However, we must not forget his pioneering work in the eastern Mediterranean and Corsica carried out in 1787 and 1788 because they also focused on territories marked by rich floristic singularities. This contribution studies the context of this plant collection in Corsica carried out by La Billardi & egrave;re in the spring of 1788, for which some gray areas persisted, and the results of his botanical prospections. At the end of the 18th century, Corsica remains very little known from a floristic point of view and La Billardi & egrave;re played a pioneering role in the knowledge of this flora by discovering several original island plants, in particular new endemic species with Tyrrhenian distribution (Arenaria balearica L., Armeria pungens (Brot.) Hoffmanns. & Link, Borago pygmaea (DC.) Chater & Greuter, Castroviejoa frigida (Labill.) Galbany, L.S & aacute;ez & Bened & iacute;, Helleborus argutifolius Viv., Noccaea brevistyla (DC.) Steud., Solenopsis corsica (Meikle) M.B.Crespo, Serra & Juan, Stachys corsica Pers.).

In the Mediterranean, the dune–beach ecosystem is characterized by the presence of thick deposits of dead leaves of the endemic seagrass Posidonia oceanica, called banquettes (Dune–Beach–Banquette ecosystem—DBB). This ecosystem plays an important role in the coupling between sea and land. The banquettes provide important ecosystem services: protection of beaches against erosion, contribution to the building of the dune, and a source of nitrogen for coastal vegetation. They are home to a rich and diverse invertebrate fauna that are consumed by other predatory invertebrates and seabirds. A conceptual model of the functioning of the DBB ecosystem and its relation with adjacent ecosystems has been outlined. When dead P. oceanica leaves return to the sea, which is the fate of most of the banquette, they constitute an important source of carbon and nutrients for coastal ecosystems and fisheries. Beach management, with the removal of banquettes and driftwood to meet the supposed requirements of beach users and tourists, is an ecological disaster, in addition to being an economic burden for coastal municipalities. Beach management methods that respect the interactions between the marine and terrestrial realms, which preserve the beaches from erosion and allow the return of the banquettes to the sea, and which take into account the real perceptions of beach users are feasible in the framework of the concept of the ‘ecological beach’.

Macaronesian oceanic islands harbour the emblematic relict Canary Islands dragon tree (D. draco (L.) L. subsp. draco, Asparagaceae). Historical records suggest that its populations, nowadays restricted to Tenerife and Gran Canaria islands (Canaries) and Madeira Island, had a much wider geographic range in the past. In this study, we aimed at (i) testing whether current D. draco subsp. draco populations are relicts of a former wider distribution because of human impact, (ii) whether those populations are at risk with future climate change and (iii) targeting priority zones for in situ conservation face to global changes. We based our approach on the comparison between actual distribution, land use data and suitable area modelled via Environmental Niche Models (ENM) and projected under future climate change scenarios. ENM were calibrated at two different phylogenetic levels to account for taxonomic uncertainties. We found that: (i) The Canary Islands dragon tree populations occupy only 3–4

Motivation: The intrinsic characteristics of islands make them a unique study system for the investigation of ecological and evolutionary dynamics. The Mediterranean Basin, an island-rich biodiversity hotspot, still lacks a comprehensive spatial database for these geographic features. This study presents the first comprehensive spatial database of all Mediterranean islands larger than 0.01 km(2), aiding ecological investigations and interdisciplinary research. Main types of variable contained: The MEDIS spatial database offers detailed information on 39 geographic, climatic, ecological and land-use variables, including island area, perimeter, isolation metrics, climatic space, terrain data, land cover, palaeogeography, road networks and geological information, providing a multifaceted view of each island's characteristics. Spatial location and grain: The study encompasses 2217 islands in the Mediterranean Basin larger than 0.01 km(2). The spatial grain of the datasets on which the selected variables are based varies from 10 m (ESA WorldCover) to 1 km (CHELSA-BIOCLIM+). Time period and grain: The spatial database incorporates data from various sources, each with its own timeframe, such as the Global Shoreline Vector from 2014 Landsat imagery and the WorldCover dataset from 2021. Historical data like the Paleocoastlines GIS dataset offer insights into island configurations during the Last Glacial Maximum. Major taxa and level of measurement: While not focusing on specific taxa, the study lays the foundation for comprehensive research on Mediterranean islands, facilitating comparisons and investigations into the distribution of native, endemic or alien species. The level of measurement is extensive, encompassing a wide range of variables and providing polygonal features rather than centroids' coordinates.

Microrefugia, defined as small areas maintaining populations of species outside their range margins during environmental extremes, are increasingly recognized for their role in conserving species in the face of climate change. Understanding their microclimatic dynamics becomes crucial with global warming leading to severe temperature and precipitation changes. This study investigates the phenomenon of short-term climatic decoupling within microrefugia and its implications for plant persistence in the Mediterranean region of southeastern France. We focus on microrefugia's ability to climatically disconnect from macroclimatic trends, examining temperature and Vapor Pressure Deficit (VPD) dynamics in microrefugia, adjacent control plots, and weather stations. Our study encompasses both “normal” conditions and heatwave episodes to explore the role of microrefugia as thermal and moisture insulators during extreme events. Landscape attributes such as relative elevation, solar radiation, distance to streams, and vegetation height are investigated for their contribution to short-term decoupling. Our results demonstrate that microrefugia exhibit notable decoupling from macroclimatic trends. This effect is maintained during heatwaves, underscoring microrefugia's vital role in responding to climatic extremes. Importantly, microrefugia maintain lower VPD levels than their surroundings outside and during heatwaves, potentially mitigating water stress for plants. This study advances our understanding of microclimate dynamics within microrefugia and underscores their ecological importance for plant persistence in a changing climate. As heatwaves become more frequent and severe, our findings provide insights into the role of microrefugia in buffering but also decoupling against extreme climatic events and, more generally, against climate warming. This knowledge emphasizes the need to detect and protect existing microrefugia, as they can be integrated into conservation strategies and climate change adaptation plans.

The classification of the Olive tree complex (Olea europaea L.) underwent numerous taxonomic changes before a consensus was seemingly reached two decades ago through the combination of morphological, chemical, cytological and molecular evidence that supported the identification of six subspecies in the Old World. While several authors claimed that Brown Olive populations from Africa and Asia were differentiated, there was no attempt to recognize two taxa due to the difficulty to distinguish them based on phenotypic characters and the possibility of a large secondary contact zone between differentiated taxa in NE Africa and the SW Arabian Peninsula. All genetic and phylogenomic studies, however, sufficiently distinguished the Asian Brown Olive, recognized here as Olea europaea L. subsp. cuspidata (Wall. ex G. Don) Cif. from the African Brown Olive, which is here reinstated as Olea europaea L. subsp. africana (Mill.) P.S. Green.

Areas where range-restricted species are concentrated are of importance for conservation. However, most of the studies aim at identifying areas rich in endemics for conservation planning, while few studies aim at understanding the causal factors of endemic richness. Here, our goal is to identify the determinants of endemic richness within a centre of endemism, the Southwestern European Alps, by testing four non-mutually exclusive hypotheses that have been proposed to explain patterns of endemic richness. In particular, we examined to what extent temporal and spatial climatic stability and environmental heterogeneity are related to endemic richness. Almost all hypotheses partially support the observed patterns of plant endemics richness within the SW Alps. In general, most of the relationships between environmental variables and endemic richness are statistically significant. However, the highest effect in explaining endemic richness is found for climate change velocity and standard deviation of slope, two factors affecting the possibility of species to disperse. This is in line with the idea that endemics are strongly limited by dispersal and not only by climate. Our results suggest that in regions where the effects of past climate changes were less dramatic endemic richness results from the interaction of species dispersal with regional and specific historical factors.