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Italy is among the European countries with the greatest plant diversity due to both a great environmental heterogeneity and a long history of man-environment interactions. Trait-based approaches to ecological studies have developed greatly over recent decades worldwide, although several issues concerning the relationships between plant functional traits and the environment still lack sufficient empirical evaluation. In order to draw insights on the association between plant functional traits and direct and indirect human and natural pressures on the environmental drivers, here we summarize the existing knowledge on this topic by reviewing the results of studies performed in Italy adopting a functional trait approach on vascular plants, briophytes and lichens. Although we recorded trait measurements for 1418 taxa, our review highlighted some major gaps in plant traits knowledge: Mediterranean ecosystems are poorly represented; traits related to belowground organs are still overlooked; traits measurements for bryophytes and lichens are lacking. Finally, intraspecific variation has been little studied at community level so far. We conclude highlighting the need of approaches evaluating trait-environment relationship at large spatial and temporal scales and the need of a more effective contribution to online databases to tie more firmly Italian researchers to international scientific networks on plant traits.

Community-weighted-mean (CWM) and functional diversity (FD) describe two aspects of plant communities' functional structure. While they have been often used separately to infer assembly processes, their covariation can actually provide useful insights into the prevalence of a particular 2 assembly process over the other. We propose a framework where positive or negative covariation of these indices can be related to different assembly processes along an environmental gradient. We tested this framework in grassland communities along elevation gradient in Central Apennines by collecting species cover and traits of the most abundant species and calculating the effect size CWM and FD. We performed major axis regression for each effect size CWM-FD relationship for different belts along the elevation gradient. The observation that Plant Height showed a positive CWM-FD relationship only under more stressful conditions indicates that there may be a tendency towards habitat filtering. Seed Mass showed positive covariation in each belt may indicate the presence of both habitat filtering and limiting similarity acting with different intensity depending on the environmental stress level. Negative covariation between CWM-Plant Height and Seed Mass-FD under less stress suggest biotic filter, while positive covariation between CWM-Plant Height and both Seed Mass and SLA FD under stressful conditions suggest the presence of habitat filtering.Ultimately, the relationship of CWM and FD may provide information on how different communities assemble along an environmental gradient. Moreover, combining the information of CWM with the FD and environmental stress level might help to identify the processes behind the same functional pattern.

Habitat monitoring in Europe is regulated by Article 17 of the Habitats Directive, which suggests the use of typical species to habitat conservation status. Yet, the Directive uses the term “typical” species but does not provide a definition, either for its use in reporting or for its use in impact assessments. To address the issue, an online workshop was organized by the Italian Society for Vegetation Science (SISV) to shed light on the diversity of perspectives regarding the different concepts of typical species, and to discuss the possible implications for habitat monitoring. To this aim, we inquired 73 people with a very different degree of expertise in the field of vegetation science by means of a tailored survey composed of six questions. We analysed the data using Pearson's Chi-squared test to verify that the answers diverged from a random distribution and checked the effect of the degree of experience of the surveyees on the results. We found that most of the surveyees agreed on the use of the phytosociological method for habitat monitoring and of the diagnostic and characteristic species to evaluate the structural and functional conservation status of habitats. With this contribution, we shed light on the meaning of “typical” species in the context of habitat monitoring.