Fluvial riparian vegetation (RV) links fluvial and terrestrial ecosystems. It is under significant pressure from anthropogenic activities, and, therefore, the management and restoration of RV are increasingly important worldwide. RV has been investigated from different perspectives, so knowledge on its structure and function is widely distributed. An important step forward is to convert existing knowledge into an overview easily accessible—for example, for use in decision-making and management. We aim to provide an overview of ecosystem services provided by RV by adopting a structured approach to identify the ecosystem services, describe their characteristics, and rank the importance of each service. We evaluate each service within four main riparian vegetation types adopting a global perspective to derive a broad concept. Subsequently, we introduce a guided framework for use in RV management based on our structured approach. We also identify knowledge gaps and evaluate the opportunities an ecosystem service approach offers to RV management.

1The Segura River Basin is one of the most arid and regulated zones in the 2 Mediterranean as well as Europe that includes four hydrologic river types, according to 3 their natural flow regime: main stem rivers, stable streams, seasonal streams and 4 temporary streams. The relationships between flow regime and fluvial and riparian 5 habitats were studied at reference and hydrologically-altered sites for each of the four 6 types. Flow regime alteration was assessed using two procedures: 1) an indirect index, 7 derived from variables associated with the main hydrologic pressures in the basin, and 82) reference and altered flow series analyses using the Indicators of Hydrologic 9 Alteration (IHA) and the Indicators of Hydrologic Alteration in Rivers (IAHRIS). 10Habitats were characterized using the River Habitat Survey (RHS) and its derived 11Habitat Quality Assessment (HQA) score, whereas riparian condition was assessed 12 using the Riparian Quality Index (RQI) and an inventory of riparian native/exotic 13 species. Flow stability and magnitude were identified as the main hydrologic drivers of 14 the stream habitats in the Segura Basin. Hydrologic alterations were similar to those 15 described in other Mediterranean arid and semiarid areas where dams have reduced flow 16 magnitude and variability and produced the inversion of seasonal patterns. Additionally, 17 the Segura Basin presented two general trends: an increase in flow torrentiality in main 18 stems and an increase in temporality in seasonal and temporary streams. With the 19 indirect alteration index, main stems presented the highest degree of hydrologic 20 alteration, which resulted in larger channel dimensions and less macrophytes and 21 mesohabitats. However, according to the hydrologic analyses, the seasonal streams 22 presented the greatest alteration, which was supported by the numerous changes in 23 habitat features. These changes were associated with a larger proportion of uniform 24 banktop vegetation as well as reduced riparian native plant richness and mesohabitat 25 density. Both stream types presented consequent reductions in habitat and riparian 26 quality as the degree of alteration increased. However, stable streams, those least 27 impacted in the basin, and temporary streams, which are subject to great hydrologic 28 stress in reference conditions, showed fewer changes in physical habitat due to 29 hydrologic alteration. This study clarifies the relationships between hydrologic regime 30 and physical habitat in Mediterranean basins. The hydrologic and habitat indicators that 31 respond to human pressures and the thresholds that imply relevant changes in habitat 32 and riparian quality presented here will play a fundamental role in the use of holistic 33 frameworks when developing environmental flows on a regional scale. 34 2

1.Understanding and predicting ecosystem responses to multiple environmental pressures is a long-standing interest in ecology and environmental management. However, few studies have examined how the functional features of freshwater biological communities vary along multiple gradients of environmental stress. Furthermore, modelling these functional features for a whole river network constitutes a strong potential basis to improve ecosystem management. 2. We explored how functional redundancy of biological communities (FR, a functional feature related to the stability, resistance and resilience of ecosystems) responds to single and multiple environmental filters. We compared these responses with those of functional richness, evenness and divergence. We used riparian vegetation of a Mediterranean basin, and three of the main environmental filters affecting freshwater communities in such regions, that is drought, flow regulation and agricultural intensity, thus considering the potential effect of natural environmental variability. We also assessed the predictability of FR and estimated it for the entire river network. 3. We found that all functional measures decreased with increasing environmental filter intensity. However, FR was more sensitive to single and multiple environmental filters compared to other functional measures. The best-fitting model explained 59% of the FR variability and included agriculture, drought and flow regulation and the pairwise interactions of agriculture with drought and flow regulation. The parameters of the FR models differed from null model expectations reflecting a non-random decline along stress gradients. 4. Synthesis and applications. We found non-random detrimental effects along environmental filters' gradients for riparian functional redundancy (the most sensitive functional index), meaning that increased stress could jeopardize stability, resistance and resilience of these systems. In general, agriculture caused the greatest impact on functional redundancy and functional diversity measures, being the most important stressor for riparian functionality in the study area. Temporary streams flowing through an agricultural, regulated basin had reduced values of functional redundancy, whereas the free-flowing medium-sized, perennial water courses flowing through unaltered sub-basins displayed higher values of functional redundancy and potentially greater stability against human impacts. All these findings along with the predicted basin-wide variation of functional redundancy can assist environmental managers in improving monitoring and ecosystem management.

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Understanding and predicting how biological communities respond to climate change is critical for assessing biodiversity vulnerability and guiding conservation efforts. Glacier‐ and snow‐fed rivers are one of the most sensitive ecosystems to climate change, and can provide early warning of wider‐scale changes. These rivers are frequently used for hydropower production but there is minimal understanding of how biological communities are influenced by climate change in a context of flow regulation. This study sheds light on this issue by disentangling structural (water temperature preference, taxonomic composition, alpha, beta and gamma diversities) and functional (functional traits, diversity, richness, evenness, dispersion and redundancy) effects of climate change in interaction with flow regulation in the Alps. For this, we compared environmental and aquatic invertebrate data collected in the 1970s and 2010s in regulated and unregulated alpine catchments. We hypothesized a replacement of cold‐adapted species by warming‐tolerant ones, high temporal and spatial turnover in taxa and trait composition, along with reduced taxonomic and functional diversities in consequence of climate change. We expected communities in regulated rivers to respond more drastically due to additive or synergistic effects between flow regulation and climate change. We found divergent structural but convergent functional responses between free‐flowing and regulated catchments. Although cold‐adapted taxa decreased in both of them, greater colonization and spread of thermophilic species was found in the free‐flowing one, resulting in higher spatial and temporal turnover. Since the 1970s, taxonomic diversity increased in the free flowing but decreased in the regulated catchment due to biotic homogenization. Colonization by taxa with new functional strategies (i.e. multivoltine taxa with small body size, resistance forms, aerial dispersion and reproduction by clutches) increased functional diversity but decreased functional redundancy through time. These functional changes could jeopardize the ability of aquatic communities facing intensification of ongoing climate change or new anthropogenic disturbances.