The vascular flora of Sardinia has been investigated for more than 250 years, with particular attention to the endemic component due to their phylogeographic and conservation interest. However, continuous changes in the floristic composition through natural processes, anthropogenic drivers or modified taxonomical attributions require constant updating. We checked all available literature, web sources, field, and unpublished data from the authors and acknowledged external experts to compile an updated checklist of vascular plants endemic to Sardinia. Life and chorological forms as well as the conservation status of the updated taxa list were reported. Sardinia hosts 341 taxa (15% of the total native flora) endemic to the Tyrrhenian Islands and other limited continental territories; 195 of these (8% of the total native flora) are exclusive to Sardinia. Asteraceae (50 taxa) and Plumbaginaceae (42 taxa) are the most representative families, while the most frequent life forms are hemicryptophytes (118 taxa) and chamaephytes (106 taxa). The global conservation status, available for 201 taxa, indicates that most endemics are under the ‘Critically Endangered’ (25 taxa), ‘Endangered’ (31 taxa), or ‘Least Concern’ (90 taxa) IUCN categories. This research provides an updated basis for future biosystematics, taxonomic, biogeographical, and ecological studies and in supporting more integrated and efficient policy tools.

Trait‐based ecology has already revealed main independent axes of trait variation defining trait spaces that summarize plant adaptive strategies, but often ignoring intraspecific trait variability (ITV). By using empirical ITV‐level data for two independent dimensions of leaf form and function and 167 species across five habitat types (coastal dunes, forests, grasslands, heathlands, wetlands) in the Italian peninsula, we found that ITV: (i) rotated the axes of trait variation that define the trait space; (ii) increased the variance explained by these axes and (iii) affected the functional structure of the target trait space. However, the magnitude of these effects was rather small and depended on the trait and habitat type. Our results reinforce the idea that ITV is context‐dependent, calling for careful extrapolations of ITV patterns across traits and spatial scales. Importantly, our study provides a framework that can be used to start integrating ITV into trait space analyses.

Despite the wide amount of scientific contributions published on alien plant species, their diffusion dynamics, and their interactions with native taxa, it is increasingly difficult to slow down their spreading and their negative impact on habitats. Last recent years, in fact, a sharp rise in the number of new alien plant taxa introduced in Italy and Europe has been recorded. The aim of this work is to investigate most of the Italian territory in order to verify whether this alarming trend is still underway. Specimen collections and/or observations of alien plants have been performed in as many as 12 Italian regions. All the collected specimens are stored in public or private herbaria. Taxa have been identified according to the literature from the countries of origin of the investigated taxa, while the nomenclature followed the current international references. Updates on 106 taxa are reported. In particular, among 117 new records, 89 are first records, 27 are changes to status and there is 1 extinction. Seven new taxa for Italian alien flora are reported, two of which are new to Europe. The administrative regions with the highest number of records are Calabria (48), Sardegna (17) and Sicilia (15). Five of the surveyed taxa, for the first time, have been considered invasive aliens to Italian territory. The unfrequent amount of original results provided by this work, over the simple importance of data itself, proves how floristic investigation, still today, represents one of the most effective tools in broadening the current knowledge about alien taxa and their dynamics.

Mediterranean pine woodlands are one of the most common wooded vegetation types across the Mediterranean Basin and are included in two habitats of European interest as they have great conservation importance. We studied the woodlands of the class Pinetea halepensis dominated by Pinus halepensis, P. pinaster, and P. pinea in Sardinia (Italy) with the aim to clarify their syntaxonomic position. We compiled a dataset of 66 original vegetation relevés, complemented with the holotypes of similar vegetation types formerly described for Italy and Corsica (France). We classified P. halepensis woodlands, native to the Island of San Pietro, to the association Erico arboreae-Pinetum halepensis. We classified P. halepensis woodlands growing on limestones of the south-western coast of Sardinia to the new association Smilaco asperae-Pinetum halepensis and woodlands typical of coastal dunes to the new association Asparago horridi-Pinetum halepensis. We also described the northeastern Sardinia P. pinaster woodlands as the new association Arbuto unedonis-Pinetum pinastri, of which we recognised two new subassociations, typicum and cephalantheretosum longifoliae, ecologically distinguished by the xerophilous and mesophilous conditions, respectively. Furthermore, we classified P. pinea woodlands, putatively native only to stabilised sand dunes of south-western Sardinia, in the new association Querco calliprini-Pinetum pineae. This study represents the first complete survey and classification of Sardinian pine woodlands, allowing a better understanding of their ecology, floristic composition and differences from other Mediterranean pine woodlands.

Temporal changes in the distribution range of plant communities and habitats should be considered for optimal conservation. However, this information is often lacking. In this research, we investigated the changes in the spatial distribution pattern of the plant communities characterised by the presence of three Mediterranean pines considered native or putative native to Sardinia (Italy), namely Pinus halepensis, P. pinaster, and P. pinea. We analysed historical and current aerial photographs to prepare maps of the past and current distribution of natural pine formations, complemented with the aid of pine-related toponymy maps and interviews with local people. We calculated how the surface of natural pine formations varied across time, and found a high rate of recovery during the last decades. This rate is doubled when compared to the average extent of other Sardinian woody formations in the same period. Among the three pine species, the area of P. halepensis and P. pinaster formations increased the most. We also found that about 90% of pine formations fall within protected areas. More than 128 ha of natural pine formations are included in the priority habitat 2270, while those included in habitat 9540 cover 1100 ha. Our study provides a complete survey of the distribution of natural Sardinian pine formations, along with the quantification of their increase in the last decades, thus highlighting the importance of diachronic analyses for monitoring spatial changes in plant communities. We suggest considering the trends in the extent of vegetation formations and habitats for conservation purposes.