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Prolonged exposure to human induced-stressors can profoundly modify the natural trajectory of ecosystems. Predicting how ecosystems respond under stress requires understanding how physical and biological properties of degraded systems parallel or deviate over time from those of near-natural systems. Utilizing comprehensive forest inventory datasets, we used a paired chronosequence modelling approach to test the effects of long-term channelization and flow regulation of a large river on changes in abiotic conditions and related riparian forest attributes across a range of successional phases. By comparing ecological trajectories between the highly degraded Rhône and the relatively unmodified Drôme rivers, we demonstrated a rapid, strong and likely irreversible divergence in forest succession between the two rivers. The vast majority of metrics measuring life history traits, stand structure, and community composition varied with stand age but diverged significantly between rivers, concurrent with large differences in hydrologic and geomorphic trajectories. Channelization and flow regulation induced a more rapid terrestrialization of the river channel margins along the Rhône River and accelerated change in stand attributes, from pioneer-dominated stands to a mature successional phase dominated by non-native species. Relative to the Drôme, dispersion of trait values was higher in young forest stands along the Rhône, indicating a rapid assembly of functionally different species and an accelerated transition to post-pioneer communities. This study demonstrated that human modifications to the hydro-geomorphic regime have induced acute and sustained changes in environmental conditions, therefore altering the structure and composition of riparian forests. The speed, strength and persistence of the changes suggest that the Rhône River floodplain forests have strongly diverged from natural systems under persistent multiple stressors during the past two centuries. These resu

Questions: What is the functional trait variation of European temperate grasslands and how does this reflect global patterns of plant form and function? Do habitat specialists show trait differentiation across habitat types?. Location: Europe. Methods: We compiled 18 regeneration and non-regeneration traits for a continental species pool consisting of 645 species frequent in five grassland types. These grassland types are widely distributed in Europe but differentiated by altitude, soil bedrock and traditional long-term management and disturbance regimes. We evaluated the multivariate trait space of this entire species pool and compared multi-trait variation and mean trait values of habitat specialists grouped by grassland type. Results: The first dimension of the trait space accounted for 23% of variation and reflected a gradient between fast-growing and slow-growing plants. Plant height and SLA contributed to both the first and second ordination axes. Regeneration traits mainly contributed to the second and following dimensions to explain 56% of variation across the first five axes. Habitat specialists showed functional differences between grassland types mainly through non-regeneration traits. Conclusions: The trait spectrum of plants dominating European temperate grasslands is primarily explained by growth strategies which are analogous to the trait variation observed at the global scale, and secondly by regeneration strategies. Functional differentiation of habitat specialists across grassland types is mainly related to environmental filtering linked with altitude and disturbance. This filtering pattern is mainly observed in non-regeneration traits, while most regeneration traits demonstrate multiple strategies within the same habitat type.