Aims: We introduce ReSurveyEurope — a new data source of resurveyed vegetation plots in Europe, compiled by a collaborative network of vegetation scientists. We describe the scope of this initiative, provide an overview of currently available data, governance, data contribution rules, and accessibility. In addition, we outline further steps, including potential research questions.Results: ReSurveyEurope includes resurveyed vegetation plots from all habitats. Version 1.0 of ReSurveyEurope contains 283,135 observations (i.e., individual surveys of each plot) from 79,190 plots sampled in 449 independent resurvey projects. Of these, 62,139 (78%) are permanent plots, that is, marked in situ, or located with GPS, which allow for high spatial accuracy in resurvey. The remaining 17,051 (22%) plots are from studies in which plots from the initial survey could not be exactly relocated. Four data sets, which together account for 28,470 (36%) plots, provide only presence/absence information on plant species, while the remaining 50,720 (64%) plots contain abundance information (e.g., percentage cover or cover–abundance classes such as variants of the Braun‐Blanquet scale). The oldest plots were sampled in 1911 in the Swiss Alps, while most plots were sampled between 1950 and 2020.Conclusions: ReSurveyEurope is a new resource to address a wide range of research questions on fine‐scale changes in European vegetation. The initiative is devoted to an inclusive and transparent governance and data usage approach, based on slightly adapted rules of the well‐established European Vegetation Archive (EVA). ReSurveyEurope data are ready for use, and proposals for analyses of the data set can be submitted at any time to the coordinators. Still, further data contributions are highly welcome.

Despite the constraining weight of summer drought over plant life which distinguishes Mediterranean high-mountains, and its anticipated exacerbation under the current climate crisis, there is still little knowledge of the underlying drought-endurance mechanisms in Mediterranean high-mountain species, such as osmolyte accumulation. To fill this gap, we studied the role of two of the most frequent osmoregulators in plants, proline and osmotically active carbohydrates (OAC), as pointers of the drought-stress response in seven high-mountain plant species representative of the high-mountain plant communities in Central Spain, along an elevation gradient. Overall, our results are consistent with the escalation of summer drought and suggest the involvement of osmolytes to sustain plant activity in these specialists during the growing season. Proline content showed a steadily increasing pattern in line with the seasonal aggravation of summer drought. The significant rise in mean proline in most species, coinciding with the periods with the greatest decline in soil water content, suggests the recurrent role of proline in the drought-stress response in the studied specialists. The lack of significant differences between elevations and the minimal seasonal variations in the OAC content suggest a fixed OAC content independent of functional type to sustain metabolic functions under summer drought. Moreover, these findings allow inferring the action of both OAC and proline as osmoregulators, allowing to support plant functions in these specialists under atypically dry conditions. Overall, our findings are consistent with proline as a major osmoprotectant strategy over OAC buildup in these specialists, which may be related to an adaptation strategy associated with the briefness of the growing season and the incidence of less favorable conditions in Mediterranean high-mountains.