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The article describes two new tall herb communities in the Southeastern Alps, Centaureo julici-Laserpitietum sileris and Laserpitio sileri-Grafietum golakae. Both are long-term successional stages in the overgrowing of abandoned hay meadows in the altimontane and subalpine belt of the southern and southwestern Julian Alps (including the Julian Prealps), partly also the Carnic Alps, that have been abandoned for over 50 years. In the succession sere where the altimontane-subalpine Illyrian beech forest (Dentario pentaphylli-Fagetum, Ranunculo platanifolii-Fagetum, Polysticho lonchitis-Fagetum) is the potential natural vegetation on steep, sunny limestone (rarely dolomite) slopes, the species Laserpitium siler and (or) Grafia golaka act as inhibitors also due to their high allelopathic potential; in turn, spontaneous afforestation with spruce and some deciduous trees has been slow and gradual. [ABSTRACT FROM AUTHOR]

Biological invasions are deemed to be the second most important global driver of biodiversity loss, right behind habitat destruction and fragmentation. In this study, we aimed at testing if community invasibility, defined as the vulnerability to invasion of a community, could be associated with the characteristics of a given habitat, as described by the composition and structure of its native species. Based on a probabilistic sampling of the alien flora occurring in the temperate wetland Lake Doberdò (Friuli Venezia Giulia region, NE Italy) and using a null-model-based approach, the observed occurrence of Invasive Alien Species (IAS) within sampling units was randomized within habitats. While testing the degree of invasibility for each habitat within the wetland, our null hypothesis postulated that habitats are equally invaded by IAS, as IAS can spread homogeneously in the environment thanks to their plasticity in functional traits that makes them able to cope with different ecological conditions. The obtained results comparing observed IAS frequencies, abundance and richness to those obtained by the null model randomizations show that, for all habitats, invasion was selective. Specifically, a marked preference for habitats with an intermediate disturbance level, a high nutrients level and a medium-high light availability was observed, while an avoidance was detected for habitats characterized by lower levels of nutrients and light availability or extreme conditions caused by prolonged submersion. This method allows us to provide useful information using a simple-to-run simulation for the management of the IAS threat within protected areas. Moreover, the method allows us to infer important ecological characteristics leading to habitat invasion without sampling the environmental characteristic of the habitats, which is an expensive operation in terms of time and money. [ABSTRACT FROM AUTHOR]

• Plants species can be considered a surrogate taxon for carabid beetles. • Cross-taxon congruence follows the gradient of vegetation in both stages. • Gradient of vegetation and the native vegetation structure influence carabid beetles. • Ailanthus altissima promotes anthropic and disturbed carabid beetles species. Ailanthus altissima is one of the most global widespread invasive alien species and its effect as habitat transformer requires detailed investigations. In particular, its invasion in natural ecosystems and its effect on local fauna should be evaluated and described. With this purpose, the identification of surrogate taxa would be an important tool in order to define the impact of this invader on different habitats. Here, we evaluated cross-taxon congruence to quantify the strength of plant species composition in predicting multivariate patterns in carabid beetle assemblages, based on data from 20 sites divided in invaded and non-invaded habitats located in the Karst area, North-east Italy. We considered the habitat type (representing vegetation stages from grassland to forest) in order to evaluate the impact of A. altissima on carabid beetles along the vegetation succession. We found 28 carabid beetles and 173 plant species. Our analyses showed that plant species composition had a valuable predictive accuracy, based on the interplay among environmental variables, soil parameters and vegetation structure. Native vegetation and habitat type were the most important factors influencing carabid beetles and plant species composition. Furthermore, 33% of the total explained variation of carabid beetles assemblages (variance partition based on RDA analysis) was due to the independent effect of environment. We proved that cross-taxon congruence between carabid beetles and plants along the successional gradient of vegetation (habitat type). In particular, we attested that both communities present more species differentiation among non-invaded vegetation; in addition, in plots were A. altissima was present , anthropic and disturbed plants and carabid beetles species were prevalent. As a conclusion, plants can be effectively used as a surrogate taxon in the evaluation of the effect of A. altissima invasion in the Karst area. [ABSTRACT FROM AUTHOR]

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., (Copyright © 2020 Elsevier Ltd. All rights reserved.)