Johannes Wessely, Kryštof Chytrý, Andreas Gattringer, Johannes Hausharter, Norbert Helm, Karl Hülber, Dietmar Moser, Otar Abdaladze, Christopher Andrews, Elena Barni, Debora Barolin, José-Luis Benito-Alonso, Raphael S von Büren, Michele Carbognani, Pau Carnicero, Valter Di Cecco, Philippe Choler, Jan Dick, Rosa Fernández-Calzado, Pieter De Frenne, Mary Carolina García Lino, Dany Ghosn, Khatuna Gigauri, Bente J Graae, Andreas Hilpold, Juan J Jiménez, Katharina Kagerl, Róbert Kanka, Jozef Kollár, Andrea Lamprecht, Jonas Lembrechts, Jonathan Lenoir, Juan Lorite, Panagiotis Nyktas, Mihai Pușcaș, Christophe F Randin, Christian Rixen, Graziano Rossi, Patrick Saccone, Tudor Mihai Ursu, Thomas Vanneste, Marco Varricchione, Pascal Vittoz, Manuela Winkler, Sonja Wipf, Harald Pauli, Stefan Dullinger
Climate change increases plant species richness in alpine ecosystems. However, to what extent this diversity enrichment masks extinction dynamics of resident species remains elusive. In this study, we used floristic resurvey data from 896 permanent vegetation plots across 62 European mountain summits to show that local extinctions have increased over the past 21 years. Extinction rates rose with the magnitude of warming, and species were more likely to go extinct toward their low-elevation range margins and in communities undergoing stronger thermophilization. Moreover, local extinctions were significantly related to preceding abundance declines, which can serve as an early warning signal. These findings suggest that despite increasing plant species richness, plant assemblages above the treeline face an accelerating but so far neglected loss of their most characteristic species.