Abstract:The plant communities on the wetlands of an agricultural landscape in central Italy were studied. Indicator species, dominant life forms, alien species cover and prevailing habitat conditions (using Ellenberg indicator values) were shown to characterize the four groups that emerged from a classification analysis. 31 vegetation units were documented by 98 original phytosociological relevés and a floristic, synecological and distributional description was presented with syntaxonomic notes for each unit. A new association, Rorippo amphibiae-Potentilletum reptantis, was described. The high phytocoenotic diversity, the 7 coenoses belonging to habitat of Community or regional interest and the higher risks affecting these wetlands in an anthropic countryside (eutrophication, invasion of alien species, human modifications of the landscape) underline the fact that these wetlands are of high conservation value and the goal of protecting this very important environment.

Aim: Vegetation types of Mediterranean thermophilous pine forests dominated by Pinus brutia, Pinus halepensis, Pinus pinaster and Pinus pinea were studied in various areas. However, a comprehensive formal vegetation classification of these forests based on a detailed data analysis has never been developed. Our aim is to provide the first broad-scale classification of these pine forests based on a large data set of vegetation plots.

Invasive alien plants are a major threat to biodiversity and they contribute to the unfavourable conservation status of habitats of interest to the European Community. In order to favour implementation of European Union Regulation no. 1143/2014 on invasive alien species, the Italian Society of Vegetation Science carried out a large survey led by a task force of 49 contributors with expertise in vegetation across all the Italian administrative regions. The survey summed up the knowledge on impact mechanisms of invasive alien plants in Italy and their outcomes on plant communities and the EU habitats of Community Interest, in accordance with Directive no. 92/ 43/EEC. The survey covered 241 alien plant species reported as having deleterious ecological impacts. The data collected illustrate the current state of the art, highlight the main gaps in knowledge, and suggest topics to be further investigated. In particular, the survey underlined competition as being the main mechanism of ecological impact on plant communities and Natura 2000 habitats. Of the 241 species, only Ailanthus altissima was found to exert an ecological impact on plant communities and Natura 2000 habitats in all Italian regions; while a further 20 species impact up to ten out of the 20 Italian administrative regions. Our data indicate that 84 out of 132 Natura 2000 Habitats (64%) are subjected to some degree of impact by invasive alien plants. Freshwater habitats and natural and semi-natural grassland formations were impacted by the highest number of alien species, followed by coastal sand dunes and inland dunes, and forests. Although not exhaustive, this research is the first example of nationwide evaluation of the ecological impacts of invasive alien plants on plant communities and Natura 2000 Habitats.

Aim Understanding the variation in community composition and species abundances (i.e., β‐diversity) is at the heart of community ecology. A common approach to examine β‐diversity is to evaluate directional variation in community composition by measuring the decay in the similarity among pairs of communities along spatial or environmental distance. We provide the first global synthesis of taxonomic and functional distance decay along spatial and environmental distance by analysing 148 datasets comprising different types of organisms and environments. Location Global. Time period 1990 to present. Major taxa studied From diatoms to mammals. Method We measured the strength of the decay using ranked Mantel tests (Mantel r) and the rate of distance decay as the slope of an exponential fit using generalized linear models. We used null models to test whether functional similarity decays faster or slower than expected given the taxonomic decay along the spatial and environmental distance. We also unveiled the factors driving the rate of decay across the datasets, including latitude, spatial extent, realm and organismal features. Results Taxonomic distance decay was stronger than functional distance decay along both spatial and environmental distance. Functional distance decay was random given the taxonomic distance decay. The rate of taxonomic and functional spatial distance decay was fastest in the datasets from mid‐latitudes. Overall, datasets covering larger spatial extents showed a lower rate of decay along spatial distance but a higher rate of decay along environmental distance. Marine ecosystems had the slowest rate of decay along environmental distances. Main conclusions In general, taxonomic distance decay is a useful tool for biogeographical research because it reflects dispersal‐related factors in addition to species responses to climatic and environmental variables. Moreover, functional distance decay might be a cost‐effective option for investigating community changes in heterogeneous environments.

The shrublands growing on siliceous and/or calcium-poor substrata of the hilly and mountainous areas of north-western and central Italy were studied. This secondary vegetation is dominated by several acidophilous shrubs like Ulex europaeus, Cytisus scoparius, Erica arborea, E. scoparia and Calluna vulgaris. The synecology, synchorology and syntaxonomy of this vegetation was studied using multivariate methods, and discussed in comparison with similar types described in other zones of the Italian peninsula. Two new subassociations are proposed here: Erico arboreae-Arbutetum unedonis genistetosum germanicae and Calluno-Sarothamnetum ericetosum scopariae. Calluno-Sarothamnetum is typified; the Sarothamnion alliance is discussed and referred to Cytisetea scopario-striati. The presence of Calluno-Ulicetea and Cytisetea scopario-striati classes is discussed, and a syntaxonomical scheme is proposed.

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The vegetation of mining dumps of SW-Sardinia includes\ud several endemic or rare species, that have\ud been confined to such artificial habitats by a millennial\ud mining activity. The extreme edaphic specialization\ud of these species reflects with unusual fidelity the\ud heterogeneity of substrata, therefore creating a system\ud of plant communities that largely contributes to\ud the environmental diversity of this part of the island.\ud The phytosociological study presented in this paper\ud recognized eight associations, distinguished by the\ud cluster analysis in two main groups, the first including\ud hemicrypto-chamaephytic vegetation, the second\ud including nanophanerophytic garigues.\ud Six associations are belonging to the first group,\ud five of which newly described: Helichryso tyrrhenici-\ud Dianthetum sardoi ass. nova occurring on\ud gross-grained, hard-sloping dumps deriving from the\ud geologic unit of Gonnesa; Coincyo recurvatae-\ud Helichrysetum tyrrhenici ass. nova colonizing\ud dumps made of metamorphitic flakes and finer particles;\ud Resedo luteolae-Limonietum merxmuelleri\ud ass. nova colonizing small-grained mining dumps\ud with high concentrations in sulphides and heavy\ud metals; Ptilostemono casabonae-Iberidetum integerrimae\ud ass. nova replacing the previous one on\ud older and more consolidated dumps, where the concentration\ud of phytotoxic elements was reduced by\ud the meteoric agents; Epipactidetum tremolsii ass.\ud nova colonizing muddy deposits originating from\ud ferrous clay; Euphorbio cupanii-Santolinetum insularis\ud ANGIOLINI & BACCHETTA 2003, occurring on\ud very old, stabilized dumps. All these associations\ud can be ascribed to the class Scrophulario-Helichrysetea\ud BRULLO, SCELSI & SPAMPINATO 1998. Within\ud this class, a new Sardo-Corsican alliance, Ptilostemono\ud casabonae-Euphorbion cupanii all. nov. is\ud here proposed, differentiated by a pool of rare or\ud endemic species. In addition to the above-mentioned associations, it is proposed, as well, to include into\ud the new alliance the Polygono scoparii-Helichrysetum\ud tyrrhenici BIONDI, VAGGE, FOGU & MOSSA 1996\ud corr., that was described for the gravelly riverbeds of\ud Central-Southern Sardinia.\ud As concerns the second group, two new association\ud have been recognized: Dorycnio suffruticosi-\ud Genistetum corsicae ass. nova, found on abandoned,\ud well consolidated mining dumps, with an upper\ud layer altered by pedogenetic processes; Polygalo\ud sardoae-Linetum muelleri ass. nova, occurring in\ud the vicinities of the mines on steep rocky slopes\ud made of Paleozoic metalliferous limestones. Both of\ud them can be ascribed to the alliance Teucrion mari\ud GAMISANS & MURACCIOLE 1985, grouping the\ud Sardo-Corsican aspects of Cisto-Lavanduletea BR.-\ud BL. in BR.-BL., MOLINIER & WAGNER 1940.\ud Two taxa are new for science: Dianthus sardous\ud BACCHETTA, BRULLO, CASTI & GIUSSO, sp. nova and\ud Helichrysum microphyllum (WILLD.) CAMB. subsp.\ud tyrrhenicum BACCHETTA, BRULLO & GIUSSO, subsp.\ud nova

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