Percorrer por autor "Burrascano, Sabina"
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- Fine‐grain beta diversity of Palaearctic grassland vegetationPublication . Dembicz, Iwona; Dengler, Jürgen; Steinbauer, Manuel J.; Matthews, Thomas J.; Bartha, Sándor; Burrascano, Sabina; Chiarucci, Alessandro; Filibeck, Goffredo; Gillet, François; Janišová, Monika; Palpurina, Salza; Storch, David; Ulrich, Werner; Aćić, Svetlana; Boch, Steffen; Campos, Juan Antonio; Cancellieri, Laura; Carboni, Marta; Ciaschetti, Giampiero; Conradi, Timo; De Frenne, Pieter; Dolezal, Jiri; Dolnik, Christian; Essl, Franz; Fantinato, Edy; García‐Mijangos, Itziar; Giusso del Galdo, Gian Pietro; Grytnes, John‐Arvid; Guarino, Riccardo; Güler, Behlül; Kapfer, Jutta; Klichowska, Ewelina; Kozub, Łukasz; Kuzemko, Anna; Löbel, Swantje; Manthey, Michael; Marcenò, Corrado; Mimet, Anne; Naqinezhad, Alireza; Noroozi, Jalil; Nowak, Arkadiusz; Pauli, Harald; Peet, Robert K.; Pellissier, Vincent; Pielech, Remigiusz; Terzi, Massimo; Uğurlu, Emin; Valkó, Orsolya; Vasheniak, Iuliia; Vassilev, Kiril; Vynokurov, Denys; White, Hannah J.; Willner, Wolfgang; Winkler, Manuela; Wolfrum, Sebastian; Zhang, Jinghui; Biurrun, IdoiaQUESTIONS: Which environmental factors influence fine-grain beta diversity of vegetation and do they vary among taxonomic groups? LOCATION: Palaearctic biogeographic realm. METHODS: We extracted 4,654 nested-plot series with at least four different grain sizes between 0.0001 m² and 1,024 m² from the GrassPlot database, covering a wide range of different grassland and other open habitat types. We derived extensive environmental and structural information for these series. For each series and four taxonomic groups (vascular plants, bryophytes, lichens, all), we calculated the slope parameter (z-value) of the power law species–area relationship (SAR), as a beta diversity measure. We tested whether z-values differed among taxonomic groups and with respect to biogeographic gradients (latitude, elevation, macroclimate), ecological (site) characteristics (several stress–productivity, disturbance and heterogeneity measures, including land use) and alpha diversity (c-value of the power law SAR). RESULTS: Mean z-values were highest for lichens, intermediate for vascular plants and lowest for bryophytes. Bivariate regressions of z-values against environmental variables had rather low predictive power (mean R² = 0.07 for vascular plants, less for other taxa). For vascular plants, the strongest predictors of z-values were herb layer cover (negative), elevation (positive), rock and stone cover (positive) and the c-value (U-shaped). All tested metrics related to land use (fertilization, livestock grazing, mowing, burning, decrease in naturalness) led to a decrease in z-values. Other predictors had little or no impact on z-values. The patterns for bryophytes, lichens and all taxa combined were similar but weaker than those for vascular plants. CONCLUSIONS: We conclude that productivity has negative and heterogeneity positive effects on z-values, while the effect of disturbance varies depending on type and intensity. These patterns and the differences among taxonomic groups can be explained via the effects of these drivers on the mean occupancy of species, which is mathematically linked to beta diversity.
- The proper middle class: assessing the importance of subordinate species on plant community assembly and functional diversityPublication . Ulrich, Werner; Matthews, Thomas; Biurrun, Idoia; Aleksanyan, Alla; Borovyk, Dariia; Burrascano, Sabina; Campos, Juan Antonio; Chusova, Olha; Czarniecka-Wiera, Marta; Czortek, Patryk; Dembicz, Iwona; Essl, Franz; Janišová, Monika; Labadessa, Rocco; Napoleone, Francesca; Pielech, Remigiusz; Vynokurov, Denys; Puchałka, Radosław; Peres-Neto, PedroABSTRACT: The local species abundance distribution (SAD) and the associated distributions of species functional traits (TADs) both result from the process of plant community assembly. Community assembly has been extensively studied for dominant and rare plants, while subordinates, the species of intermediate abundance in a community, have received less research attention although this group is comparatively species rich and important for community functioning. Here, we study the functional role of subordinate species (those covering the intermediate 50% of abundance ranks) using a large data set of Palearctic dry and semi-dry grassland plant communities and data on specific leaf area, seed mass and plant height. Our findings indicate that species rank orders of SADs and TADs tend to be negatively correlated, causing the TAD to have higher evenness than the associated SAD. Subordinate species represented on average less than 15% of total plant abundance and trait space. Functional diversity of subordinates was lower than expected by a null model that assumed an equiprobable random distribution of trait values among plant species. Climate seasonality and elevation appeared to be the most important drivers of subordinate abundance and functional diversity. We conclude that subordinates differ from dominants in trait composition, leading to their partial functional independence from dominants.