Plants can slow water and trap sediment with their canopies and stabilise sediment with their roots. These influences are mediated by the characteristics or traits of the vegetation. Here, we review and investigate the flexibility, size, root form, clonal growth, perennation and Ellenberg F values of 459 European riverine species, considering their role in physical and ecological processes. We make use of existing plant trait datasets to create two typologies: one that identifies the role vegetation has in channel blockage (conveyance) and sediment accrual and a second typology, that indicates vegetation's ability to stabilize sediment. The two typologies are tools for interpreting botanical survey data collected using standard techniques across large numbers of sites as part of the European Union Water Framework Directive monitoring programmes. As such, they are designed to be used to indicate broad-scale patterns across sites rather than detailed insights into site-specific processes.

Over the last decades, rivers and fluvial corridors have been noticeably modified from their natural conditions. In general, damming and other in-channel human interventions have been traditionally considered as the main drivers of change. However, recent studies highlight the influence of climate, hillslope and floodplain cover changes over fluvial corridor dynamics. The present study illustrates the channel morphology and riparian vegetation responses observed in three gravel bed rivers located in the Upper Esla River, north-west of Spain. The entire study catchment was exposed to afforestation changes and farmland abandonment during the last decades, and two of the rivers are regulated by large dams. Analysis of historical orthophotos at different periods between 1956 and 2011 allowed quantifying channel narrowing, reduction of braiding index and vegetation encroachment along the three rivers. Field reconnaissance of landforms and vegetation structure along transects showed significant differences in species composition and age structure between the non-regulated reach, where recruitment of Salicacea pioneer species existed, and the regulated reaches where mature and late-seral species were much more abundant. These responses were consistent with reductions in mean annual discharge in all rivers and with flood disturbance decrease and summer minimum flow increase that were observed in the regulated rivers.

Frost determines the evolution and distribution of plants in temperate and cold regions. Several environmental factors can influence frost acclimation of woody plants but the magnitude and direction of the effect of nitrogen (N) availability is controversial. We studied the effect of N availability on root and shoot frost tolerance in mid-fall and in winter in seedlings of four pines of contrasting ecology: Pinus nigra J.F. Arnold, P. pinaster Ait., P. pinea L. and P. halepensis Mill.. Organ N and soluble sugar concentration, and timing of cessation of shoot elongation were measured to assess the physiological mechanisms underlying frost acclimation. Nitrogen was supplied at high and low rates only during the pre-hardening period and at a moderate N rate during hardening in the fall. Shoot frost tolerance increased over winter while root frost tolerance did not change in any species. Pre-hardening N availability affected the frost tolerance of both roots and shoots, although the effect was species-specific: high N reduced the overall root and shoot frost tolerance in P. pinea and P. halepensis, and increased the frost tolerance in P. nigra, but had no effect in P. pinaster. Nitrogen supply in the fall consistently increased frost tolerance in all species. Differences in frost tolerance among species and N treatments were not explained by variations in organ N or soluble carbohydrate concentration, nor by timing of cessation of shoot elongation; however, the most frost tolerant species ceased elongation earlier than the least frost tolerant species. Despite the close phylogenetic relatedness of the studied species, the effect of N availability on seedling frost tolerance differed among species, indicating that species ecology (especially frost acclimation physiology) and timing of N supply drives the effect of N availability on frost tolerance of pine species.

Abstract. The main goal of this study was to create a database that ultimately serves further studies on riparian vegetation and flow response guilds in the boreal region and on transferability of results across different regions. To achieve this aim, we compiled traits for all woody riparian species in northern Sweden which, directly or indirectly, underlie their responses to hydrological and hydraulic conditions, between October 2012 and April 2015. Consulted sources of information were diverse, ranging from scientific to informative and whose accuracy might or might not be verified. They were focused on particular or several traits and species from concrete areas to a worldwide perspective. Sources were characterized by different degrees of accessibility and showed a wide variety of descriptions, categorical and ordinal classifications, and numerical information for each trait. Our effort was to synthesize information for each trait from all sources into the common frame of our own database, following own defined criteria so that comparisons between species are congruent. Therefore, this data set is unique in that it comprehensively combines and homogenizes morphological, phenological, reproductive, and ecological data for 59 woody, riparian, boreal species and from 118 sources of information, that would otherwise be scattered and hardly available.