Summary1. Spatially explicit understanding of the delivery of multiple ecosystem services (ES) from global to local scales is currently limited. New studies analysing the simultaneous provision of multiple services at landscape scale should aid the understanding of multiple ES delivery and trade-offs to support policy, management and land planning. 2. Here, we propose a new approach for the analysis, mapping and understanding of multiple ES delivery in landscapes. Spatially explicit single ES models based on plant traits and abiotic characteristics are combined to identify 'hot' and 'cold' spots of multiple ES delivery, and the land use and biotic determinants of such distributions. We demonstrate the value of this trait-based approach as compared to a pure land-use approach for a pastoral landscape from the central French Alps, and highlight how it improves understanding of ecological constraints to, and opportunities for, the delivery of multiple services. 3. Vegetative height and leaf traits such as leaf dry matter content were response traits strongly influenced by land use and abiotic environment, with follow-on effects on several ecosystem properties, and could therefore be used as functional markers of ES. 4. Patterns of association among ES were related to the dominant traits underlying different ecosystem properties. The functional decoupling between height and leaf traits provided alternative pathways for high agronomic value, as well as determining hot and cold spots of ES. Traditional land uses such as organic fertilization and mowing or altitude summer grazing were also linked with ES hot spots, because functional characteristics supporting fodder production and quality are compatible with species and functional diversity. 5. Synthesis. Analyses of ES using plant functional variation across landscapes are a powerful approach to understanding the fundamental ecological mechanisms underlying ES provision, and trade-offs or synergies among services. Sustainable management of species and functionally diverse grassland could simultaneously aim at conserving biodiversity and locally important ES by taking advantage of correlations and trade-offs among different plant functional traits.

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Summary Here, we analysed the role of direct and indirect plant interactions in the invasion process of Acer negundo along a natural successional gradient in the Middle Rhone floodplain (France). We addressed two questions: What are the responses of the invasive Acer seedlings to native communities’ effects along the successional gradient? What are the effects of the invasive Acer adult trees on the native communities? In the three communities (Salix, Acer and Fraxinus stands) we transplanted juveniles of the invasive and juveniles of the natives within the forest and in experimental gaps, and with and without the herb layer. We also quantified changes in understory functional composition, light, nitrogen and moisture among treatments. Acer seedlings were directly facilitated for survival in the Salix and Acer communities and indirectly facilitated for growth by adult Acer through the reduction of the abundance of highly competitive herbaceous competitors. We conclude that direct facilitation by the tree canopy of the native pioneer Salix is very likely the main biotic process that induced colonization of the invasive Acer in the floodplain and that indirect facilitation by adult conspecifics contributed to population establishment.

This review examines the ecological traits and ecophysiological characteristics of the common ash (Fraxinus excelsior L.) that help to explain the current spread of ash communities in Europe. As a consequence of anthropogenic disturbance, the common ash has experienced new environmental conditions and the frequency of the species has fluctuated over space and time. Owing to its ubiquity, over the last few decades the common ash has been greatly favoured in areas abandoned by agriculture and also along impounded rivers. F. excelsior is a mesophilic species that usually thrives on alluvial soils and can also survive the strong water deficit on hillslopes. Drought tolerance in ash trees is related to stomatal regulation, a decrease in osmotic potential and also an increase in the elastic modulus ε. Malic acid plays a central role in drought tolerance, first as one of the major solutes involved in osmotic adjustment, and second as an effector for stomatal regulation through a drought-induced increase in its xylem concentration.

Living plants have been used for a very long time throughout the world in structures against soil erosion, as traces have been found dating back to the first century BC. Widely practiced in Western Europe during the eighteenth and nineteenth centuries, bioengineering was somewhat abandoned in the middle of the twentieth century, before seeing a resurgence in recent times. Based on an extensive bibliography, this article examines the different forms of bioengineering techniques used in the past to manage rivers and riverbanks, mainly in Europe. We compare techniques using living material according to their strength of protection against erosion. Many techniques are described, both singly and in combination, ranging from tree planting or sowing seeds on riverbanks to dams made of fascine or wattle fences. The recent appearance of new materials has led to the development of new techniques, associated with an evolution in the perception of riverbanks.

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The restoration of floodplain woodlands demands an understanding of the linkages between process, form and past management history at both a local and catchment scale. Site and reach scale processes that influence the species composition of floodplain woodland species are described with a particular focus on the relationships between hydrological and sediment inputs to floodplains and the regeneration response by tree species. The importance of integrating natural science knowledge gained at the site reach scale with decisions taken at the catchment scale on water allocation priorities is then discussed.Research was carried out on the River O 8 re in Sweden, The River Ouse in the United Kingdom and the River Isère and River Garonne in France. Research results at the site and reach scale allow broad definition of ideal conditions for the regeneration and growth of floodplain tree species and the flows that provide them: (1) channel movement has to occur for the creation of sedimentation sites required for the regeneration of early successional species and the flows that provide them; (2) flooding events should occur periodically to cause both channel movement and recharge floodplain water tables; (3) water table decline rates following a flood event must be slow enough that seedling roots can maintain contact with the retreating water front; (4) unseasonal flood events can cause high mortality of seedlings and prevent successful regeneration in any season. Some of the requirements for the restoration of floodplain woodlands can be delivered through site and reach scale restoration projects with reasonably predictable ecological outcomes. A more holistic approach to the provision of regeneration sites for floodplain woodlands would also include water allocation decisions targeted at providing flow conditions which could restore geomorphological processes. However, it is difficult to predict ecosystem responses to catchment scale flow allocation measures and, therefore, in the intensively managed river corridors of Western Europe, river restoration initiatives tend to be restricted to the site and reach scale.

-Poplars occur in riparian areas where the water table depth generally varies with the elevation of the adjacent river. Changes in stream flow caused by diversion projects can affect the riparian community; this may lower the water table below the rooting zone of some tree species and cause then to suffer from a water shortage. Obligate riparian trees require access to a permanent water supply and are usually intolerant to low water potentials, being poorly adapted to water stress. In this paper, the survival of black poplars (Populus nigra) downstream of a dam constructed in the 1960s on the Drac river at the foot of the French Alps is reported. The growth, water consumption, and water status of some of these trees are compared with those of other poplars located downstream and growing under wetter conditions. Although water consumption and development were quite different for both, their method of water regulation seemed to be quite similar.Populus nigra / dendrochronological studies / sap flow / drought tolerance Résumé -Survie et adaptation de Populus nigra à des conditions plus sèches suite à la construction d'un barrage sur une rivière des Alpes dans le sud-est de la France. Les peupliers poussent le long des rivières où la profondeur de la nappe varie avec le niveau de la rivière adjacente. Les changements de débit suite aux modifications de l'écoulement, peuvent affecter les forêts riveraines : ceci peut faire abaisser la hauteur de la nappe en dessous du système racinaire de certains arbres et leur réduire ainsi l'accès à l'eau. Ces arbres phréatophytes ont besoin d'un accès permanent à l'eau et sont généralement intolérant à la sécheresse et peut adaptés au stress hydrique. Dans cette étude, la survie de peupliers noirs (Populus nigra) en aval d'un barrage construit dans les années 1960 sur le Drac au pied des Alpes est décrite. La croissance, la consommation en eau et l'état hydrique de ces arbres sont comparés à d'autres peupliers poussant plus en aval dans des zones plus humides. Bien que leur consommation en eau et leur développement sont différents, leur mode de régulation de l'eau semble bien être similaire.Populus nigra / dendrochronologie / flux de sève / tolérance à la sécheresse