Format: ORAL

Marco Vuerich1,2, Francesco Boscutti1,2, Davide Mosanghini1, 3, Giacomo Trotta1, Graziano Rossi4, Francesco Porro4, Simone Orsenigo4, Silvano Lodetti4, Margherita Tognela4, Elena Barni5, Ludovica Oddi5, Umberto Morra di Cella6, Angela Stanisci7, Maria Laura Carranza8, Pau Carnicero9, Brigitta Erschbamer9, Lena Nicklas9, Michele Carbognani10, Tai GW Forte10, Marcello Tomaselli10, Alessandro Petraglia10

1 Department of Agricultural, Food, Environmental and Animal Sciences, University of Udine, via delle Scienze 91, 33100 Udine, Italy; 2 NBFC, National Biodiversity Future Center, 90133 Palermo, Italy 3 FOR NATURE SRL, Via T. Ciconi, 26, 33100 Udine, Italy; 4 Department of Earth and Environmental Sciences, University of Pavia, Via Sant’Epifanio 14, 27100 Pavia, Italy; 5 Department of Life Sciences and Systems Biology, University of Turin, Viale Mattioli 25, 10125 Turin, Italy; 6 Aosta Valley Regional Environmental Protection Agency, loc. La Maladière 48, 11020 Saint-Christophe, Italy Department of Botany; 7 Department of Bioscience and Territory, University of Molise, Via Duca degli Abruzzi 67, 86039 Termoli, Italy; 8 Department of Bioscience and Territory, University of Molise, Contrada Fonte Lappone snc, 86090 Pesche (IS), Italy 9 Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria; 10 Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/A, 43124 Parma, Italy

Plant species and communities distribution are remarkably affected by the climate change, particularly in arctic and alpine biomes. In alpine ecosystems, species and communities are shifting upwards due to the temperature increase, seeking for the optimum growth conditions. As a prominent effect, a progressive increase of vegetation cover is leading an alpine greening, with important consequences for the overall plant diversity. Nonetheless, little is known about how this trend may produce different effects along elevation gradients. Innovative upscaling approaches able to link field monitoring evidence to remote sensing data represent a promising tool to get new insights into the ecological mechanisms involved in these changes, and to produce reliable projections over time. This study aimed at parsing the long-term trends of remote sensing-derived vegetation indices in five GLORIA network target regions, located across the Italian Alps and Apennines. NDVI was calculated for each growing season (June-September) in the period 1985-2022, using Landsat 5 and 8 multispectral satellite images of each mountain summit. Linear mixed-effects models were used to analyze the relationships between NDVI, time and climate variables, in different elevation belts. NDVI linearly increased over the last 37 years, but with significant higher increase rates and values at the treeline, lower alpine and alpine zones, compared to the upper alpine, subnival and nival belts. Moreover, NDVI was significantly affected by the interaction between temperature and rain precipitation at lower altitudes. These results provided further evidence of the ongoing alpine greening and showed that vegetation at the treeline is responding faster than the other communities to a warmer and drier climate. Therefore, future scenarios depicting the fate of alpine plant community communities should not neglect for the interplay of temperature and precipitation regimes. Our finding opens future perspectives on the interpretation of GLORIA field evidence, in a continental upscalingperspective.