Harald Pauli et al. 10 páginas, 2 figuras ; [EN] In mountainous regions, climate warming is expected to shift species' ranges to higher altitudes. Evidence for such shifts is still mostly from revisitations of historical sites. We present recent (2001 to 2008) changes in vascular plant species richness observed in a standardized monitoring network across Europe's major mountain ranges. Species have moved upslope on average. However, these shifts had opposite effects on the summit floras' species richness in boreal-temperate mountain regions (+3.9 species on average) and Mediterranean mountain regions (–1.4 species), probably because recent climatic trends have decreased the availability of water in the European south. Because Mediterranean mountains are particularly rich in endemic species, a continuation of these trends might shrink the European mountain flora, despite an average increase in summit species richness across the region. ; Baseline data were collected within the European Union FP-5 project GLORIA-Europe (EVK2-CT-2000–0006) and with the support of Switzerland (OFES 00.0184-1). Resurvey was supported by the Swiss MAVA Foundation for Nature Conservation and by a number of national funding agencies, and analysis was supported by the Austrian Federal Ministry of Science and Research; the Austrian Academy of Sciences (Institute of Mountain Research); and the University of Vienna, where data are archived in the central GLORIA database and are available from the authors upon request. We thank the European Topic Centre on Biological Diversity for ambituos discussions in the early stage, C. Klettner for data compilation, S. Laimer for administration assistance, 17 GLORIA-Europe field teams with more than 80 fieldworkers for species recording, and protected-area authorities for logistic support. We also thank three anonymous referees for their valuable comments and suggestions. ; Peer reviewed