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The vegetation databank established by our working group covers the classes FestucoBrametea. Koelerio-Corynephoretea, and Trifolio-Geranietea sanguinei in the Nordic and Baltic region. i.e. NE Germany, Denmark, Norway, Sweden, Finland. N Poland. Lithuania, Latvia, Estonia. and NW Russia. We aim to use these data to develop a consistent supra-national phy~ tosociological classification of these xerothermic vegetation types in the study area and to analyse their biodiversity patterns. Up to now, we located some 12,500 releves meeting our criteria, and more than 3.500 of them have already been included in the databank. We give an overview of the properties of these releves as regards coverage of syntaxa and countries, source types, plot sizes, and cryptogam treatment. We also present first analyses for the basiphilous semi·dry grasslands (Brachypodietalia pinnati) within the Festuco-Brometea. For this group of communities, many different and incompatible classification schemes have been proposed. We givc an overview of the alliance and aSsociation names that have been in use for them in the study area, accompanied by a nomenclatural assessment. The releves presently included in the databank havc been tentatively assigned to those vegetation classes whose diagnostic taxa were prevailing. Accordingly, morc than 2.000 releves have been placed in the Festuco-Brometea. These show considerable floristic differenccs compared to stands of the southern temperate Brachypodietalia pinnati alliances Bromion erecti, Cirsio-Brachypodion pinnati, and Agrostionvinealis. The presence degrees of Avenula pratensis and Homalothecium lutescens, for instance, are significantly increased in the study area, and those of Festuca rupieola and Euphorbia cyparissias decreased. An analysis of the species-area relationship yielded a power function with z = 0.09 which is considerably lower than increments determined by nested-plot analyses of this community type, indicating the probable incompleteness of the species lists for many of the larger plots. Finally, we give an outlook on the future objectives of the working group.

The vegetation databank established by our working group covers the classes FestucoBrametea. Koelerio-Corynephoretea, and Trifolio-Geranietea sanguinei in the Nordic and Baltic region. i.e. NE Germany, Denmark, Norway, Sweden, Finland. N Poland. Lithuania, Latvia, Estonia. and NW Russia. We aim to use these data to develop a consistent supra-national phy~ tosociological classification of these xerothermic vegetation types in the study area and to analyse their biodiversity patterns. Up to now, we located some 12,500 releves meeting our criteria, and more than 3.500 of them have already been included in the databank. We give an overview of the properties of these releves as regards coverage of syntaxa and countries, source types, plot sizes, and cryptogam treatment. We also present first analyses for the basiphilous semi·dry grasslands (Brachypodietalia pinnati) within the Festuco-Brometea. For this group of communities, many different and incompatible classification schemes have been proposed. We givc an overview of the alliance and aSsociation names that have been in use for them in the study area, accompanied by a nomenclatural assessment. The releves presently included in the databank havc been tentatively assigned to those vegetation classes whose diagnostic taxa were prevailing. Accordingly, morc than 2.000 releves have been placed in the Festuco-Brometea. These show considerable floristic differenccs compared to stands of the southern temperate Brachypodietalia pinnati alliances Bromion erecti, Cirsio-Brachypodion pinnati, and Agrostionvinealis. The presence degrees of Avenula pratensis and Homalothecium lutescens, for instance, are significantly increased in the study area, and those of Festuca rupieola and Euphorbia cyparissias decreased. An analysis of the species-area relationship yielded a power function with z = 0.09 which is considerably lower than increments determined by nested-plot analyses of this community type, indicating the probable incompleteness of the species lists for many of the larger plots. Finally, we give an outlook on the future objectives of the working group.

Salt marshes play an important role in coastal protection by reducing the impact of waves and shoreline erosion risks. While mature vegetation is responsible for the persistence and stability of marsh ecosystems, seedling survival of pioneer species is especially crucial for marsh propagation. Marsh seedlings, however, may be threatened by climate change induced increased coastal storm surge intensity and accompanying (extreme) wave conditions, imposing stronger drag forces on marsh seedlings. We test the hypothesis that drag forces experienced by seedlings increase with horizontal orbital velocity (Uw) in a species-specific manner, and that the drag forces experienced are individual-plant trait-mediated. To test our hypotheses, seedlings of four contrasting pioneer marsh species (Bolboschoenus maritimus, Schoenoplectus tabernaemontani, Spartina anglica, and Puccinellia maritima) were exposed to storm wave conditions in a flume, where Uw and experienced drag forces were measured. Linear mixed effect models demonstrated that seedling’s susceptibility to storm wave conditions is at least partly mediated by individual plant traits. Drag forces experienced by seedlings tended to increase with Uw, and with stem length and diameter. The interplay of both traits was complex, with increasing stem length being the most important trait accounting for increases in drag forces experienced at low to moderate Uw, while the stem diameter became more important with increasing Uw. Furthermore, experienced drag forces appeared to be affected by species-specific traits such as rigidity and leaf growth, being highest for Bolboschoenus maritimus and lowest for Puccinellia maritima. Our results provide important mechanistic insights into the drivers of tidal marsh seedling vulnerability to storm wave conditions due to experienced drag, both based on the traits of individual plants and species-specific ones. This type of knowledge is of key importance when modelling saltmarsh establishment and resilience under climate change.

Abstract The extensive spatial and temporal coverage of many citizen science datasets (CSD) makes them appealing for use in species distribution modeling and forecasting. However, a frequent limitation is the inability to validate results. Here, we aim to assess the reliability of CSD for forecasting species occurrence in response to national forest management projections (representing 160,366 km2) by comparison against forecasts from a model based on systematically collected colonization–extinction data. We fitted species distribution models using citizen science observations of an old‐forest indicator fungus Phellinus ferrugineofuscus. We applied five modeling approaches (generalized linear model, Poisson process model, Bayesian occupancy model, and two MaxEnt models). Models were used to forecast changes in occurrence in response to national forest management for 2020‐2110. Forecasts of species occurrence from models based on CSD were congruent with forecasts made using the colonization–extinction model based on systematically collected data, although different modeling methods indicated different levels of change. All models projected increased occurrence in set‐aside forest from 2020 to 2110: the projected increase varied between 125% and 195% among models based on CSD, in comparison with an increase of 129% according to the colonization–extinction model. All but one model based on CSD projected a decline in production forest, which varied between 11% and 49%, compared to a decline of 41% using the colonization–extinction model. All models thus highlighted the importance of protected old forest for P. ferrugineofuscus persistence. We conclude that models based on CSD can reproduce forecasts from models based on systematically collected colonization–extinction data and so lead to the same forest management conclusions. Our results show that the use of a suite of models allows CSD to be reliably applied to land management and conservation decision making, demonstrating that widely available CSD can be a valuable forecasting resource.