Invasive plants are a major cause of diversity decline and altered ecosystem functioning in freshwater systems, with high connectivity making them particularly susceptible to new introductions and spread. While studies of plant invasion hotspots have used geopolitical regions to understand global patterns, freshwater plant invasions are better understood at the scale of basins. By combining the inventory of species in the Global Naturalized Alien Flora with aquatic habitat status of all those species and their global occurrence records, we analysed the richness of non-native freshwater plants found in freshwater basins worldwide. After accounting for basin area and sampling effort, we found that the pattern of freshwater plant hotspots differs from that of terrestrial plants. There are basins on all ice-free continents with higher-than-expected non-native freshwater plant richness, though there are relatively few such basins in Europe. Importantly, almost a third of all RAMSAR Convention wetland sites occur in basins with at least 10 non-native freshwater plant species. Our findings demonstrate that freshwater plant invasions may present a considerable risk to the conservation of key freshwater ecosystems on all continents, but better surveillance of wetland sites is needed to separate current invasion levels from future risk.

ABSTRACT A primary ecological challenge is to disentangle how abiotic factors affect species richness using measured environmental variables in addition to broad proxies such as elevation. Considering direct ecogeographical gradients, such as climate harshness, it is therefore essential to understand whether these underlying abiotic factors might consistently drive the distribution of different groups of organisms along elevational gradients. To address how elevation shapes species richness patterns, we performed a systematic review and a subsequent meta‐analysis to answer the following questions: (i) Does elevation influence species richness in global freshwater zooplankton and macrophyte communities? (ii) Can climatic harshness, such as temperature and precipitation variability, geography and different freshwater ecosystem types explain relationships between elevation and species richness? (iii) Are these ecogeographical patterns consistent for both organismal groups? Our meta‐analysis included 84 effect sizes spanning 48 countries and both hemispheres from −54.9 S to 84.7 N, with an elevational range up to 4200 m above sea level within six distinct freshwater ecosystems. We found that the relationship between elevation and species richness in zooplankton and macrophyte communities is context‐dependent. These responses varied among different taxonomic groups and broad habitat categories (i.e., flowing vs. standing waters). We found a general negative relationship between zooplankton species richness and elevation. Zooplankton species richness decreased along the elevational gradient, but this pattern was primarily associated with a concomitant decrease in cladoceran species numbers. The negative correlation between elevation and species richness was observed solely in flowing waters for macrophytes. Additionally, we found that negative elevation–richness relationships were more pronounced at high latitudes in the global north for both zooplankton and macrophyte communities. This research challenges the prevailing assumption that elevational diversity gradients are universal, with species richness decreasing with increasing elevation in freshwater ecosystems. We also emphasize that the conventional ecogeographical measures employed in terrestrial studies, such as air temperature, may be insufficient on their own to explain richness patterns in freshwater organisms. These findings underscore the necessity for future freshwater assessments to build on well‐established biogeographical traditions rooted in terrestrial systems while recognizing the unique features of inland waters.

Reintroduction of keystone species is considered part of the solution to the current biodiversity crisis. The Eurasian beaver (Castor fiber) is one such species, shaping its habitat by felling trees, building dams and creating wetlands. However, whilst the potential benefits to aquatic biodiversity and ecological functioning have been studied on a local scale, the impacts of beavers on catchment-scale processes such as fish migration remain understudied. Sequencing of environmental DNA (eDNA metabarcoding) from water samples is a cost-effective method to study species distributions across large geographical scales. Here, eDNA samples (n = 426) were collected from 142 sites across Britain's oldest and largest established wild beaver population, located on Tayside, East Scotland and analysed using a vertebrate-specific metabarcoding assay. We combined detection/non-detection data from eDNA results with other environmental and anthropogenic variables to model the effects of beaver eDNA detections on the distribution of three migratory fish species. Using generalised linear models, we found no effects of the current beaver eDNA detections on the distribution of Atlantic salmon or lamprey, but a positive co-occurrence with European eel at the catchment scale. Model outputs also reinforced previous findings on the impact of barriers to migration and other abiotic and biotic factors on fish species, demonstrating the effectiveness of eDNA sampling in rivers for understanding species distributions at a catchment scale. Synthesis and applications. This study provides novel insights into the catchment-scale co-distribution of beavers and migratory fish, and there was no evidence of negative effects on the catchment-scale distribution of migratory fish species. More generally, this study highlights how catchment-wide eDNA monitoring can be applied by environmental managers to aid decision-making and impact assessment of multiple priority species at the catchment scale.

Globally, freshwater environments are threatened by point source and diffuse pollution, habitat loss, and climate change. Enhancing water quality and reducing microbial pollution are priorities to realise their ecosystem services potential but challenging to achieve and require creative solutions. Beavers are receiving increasing attention as ecosystem engineers, their dams benefitting aquatic ecosystems via improved biodiversity, water quality, and flow regulation. However, effects on microbial water quality remain uncertain. Here, we investigated the influence of engineering by Eurasian beaver (Castor fiber L.) on variation in Escherichia coli concentrations and turbidity in an agricultural stream. Water samples were collected over a period of two years (2017-2019, encompassing 11 sampling dates), from a sequence of 14 beaver dams and associated ponds to quantify fluxes of turbidity and E. coli. On average, dam structures were a source whereas ponds acted as a sink for both turbidity and E. coli. The sink effect of ponds strengthened with upstream load, increasingly outweighing the source effect of dams while being moderated by season and antecedent flow and rainfall. To complement these findings, in 2023, an in-situ pollution event was simulated by adding a slurry of livestock manure (25 l) to two nearby closely comparable streams, one beaver-engineered, the other not (control), and tracking the downstream distribution of waterborne E. coli. Consistent with our field sampling campaign, E. coli was strongly attenuated in beaver ponds, which reduced peak concentrations by >95 % and slowed the flushing of E. coli compared to the control stream. Our study demonstrates that beaver dams exert a range of effects on microbial and associated pollution but, importantly, under peak loading can significantly decrease pollution reaching downstream receptors. Beaver dams, and potentially their analogues, could therefore support environmental management strategies in agricultural systems as part of a suite of nature-based approaches.

AimThere is compelling evidence that drivers and patterns of biodiversity and ecosystem functioning vary across multiple spatial scales, from global to regional, landscape and patch. However, macroecological processes impacting freshwater biodiversity are poorly understood compared to marine and terrestrial ecosystems. Despite step changes in data availability, we have a fragmented view beyond the local scale of how hydrological and landscape connectivity interact with ecosystem stressors to shape freshwater biodiversity and functioning. While macroecological patterns can vary substantially among taxonomic groups, previous studies have focussed on individual habitat types, sites or taxonomic groups within landscapes, hindering direct comparisons. We present a cross-landscape, multi-species analysis of the interactive effects of landscape and hydrological connectivity and stressors on standing freshwater quality and the diversity of several major freshwater taxonomic groups.LocationGreat Britain (United Kingdom).Time Period2000-2016.Major Taxa StudiedPhytoplankton chlorophyll-a, macrophytes, molluscs, Coleoptera, Odonata, fish and birds.MethodsUsing random forests and generalised additive modelling, we quantified the interactive effects of landscape and hydrological connectivity and stressors on water quality (phytoplankton chlorophyll-a) and the diversity of selected taxa in standing freshwaters.ResultsWe found evidence of connectivity changing from positive to negative relationships with biotic responses with increasing human-induced stress levels. Some species groups showed the inverse, reflecting complexities of modelling at large, cross-landscape scales. Almost all responses were affected by stress or connectivity, often interacting and with non-linear relationships.Main ConclusionsPatterns in stressor-connectivity interactions differed across taxa, but were important in shaping 6 of 8 biotic responses. This emphasises the need for taxon-specific analyses to resolve freshwater ecological responses to stressors, connectivity, and their interactions. Our results also highlight that connectivity effects must be integrated in landscape-scale, evidence-led decision-making, designed to reduce impacts of stressors on water quality and biodiversity.

ABSTRACTRiverbank erosion is a naturally occurring process that influences riparian zone habitats. However, anthropogenic activities are increasing rates of riverbank erosion. Climate change and hydrological and physical modifications drive riparian zone perturbations. Whilst native riparian vegetation can reduce riverbank erosion, the proliferation of non‐native riparian plant species has been linked to riverbank instability, with marked changes in fluvial erosional regimes attributed to invasion by species such as Impatiens glandulifera (Himalayan Balsam) or Tamarix (Tamarisk) into riparian zones. Yet, the role of non‐native plant species in modulating riverbank erosion remains unclear, in part due to the lack of investigations that quantify geomorphic change. We systematically assessed the relevant ecological and geomorphological literature to determine current understanding and to offer recommendations for future research on non‐native plant—riverbank erosion. Included articles focused on a limited number of non‐native plant species across a restricted range of habitats types, with dependency on topographic change and generally short study duration obscuring potential causal links or feedback cycles. It is critical in the face of parallel rapid proliferation of riparian non‐native plant species and climate change effects, that we improve mechanistic understanding of their role in riverbank erosion.

Idiosyncratic decisions during the biodiversity trend assessment process may limit reproducibility, whilst 'hidden' uncertainty due to collection bias, taxonomic incompleteness, and variable taxonomic resolution may limit the reliability of reported trends. We model alternative decisions made during assessment of taxon-level abundance and distribution trends using an 18-year time series covering freshwater fish, invertebrates, and primary producers in England. Through three case studies, we test for collection bias and quantify uncertainty stemming from data preparation and model specification decisions, assess the risk of conflating trends for individual species when aggregating data to higher taxonomic ranks, and evaluate the potential uncertainty stemming from taxonomic incompleteness. Choice of optimizer algorithm and data filtering to obtain more complete time series explained 52.5% of the variation in trend estimates, obscuring the signal from taxon-specific trends. The use of penalized iteratively reweighted least squares, a simplified approach to model optimization, was the most important source of uncertainty. Application of increasingly harsh data filters exacerbated collection bias in the modelled dataset. Aggregation to higher taxonomic ranks was a significant source of uncertainty, leading to conflation of trends among protected and invasive species. We also found potential for substantial positive bias in trend estimation across six fish populations which were not consistently recorded in all operational areas. We complement analyses of observational data with in silico experiments in which monitoring and trend assessment processes were simulated to enable comparison of trend estimates with known underlying trends, confirming that collection bias, data filtering and taxonomic incompleteness have significant negative impacts on the accuracy of trend estimates. Identifying and managing uncertainty in biodiversity trend assessment is crucial for informing effective conservation policy and practice. We highlight several serious sources of uncertainty affecting biodiversity trend analyses and present tools to improve the transparency of decisions made during the trend assessment process.

Beavers act as 'ecosystem engineers' by altering watercourses through dam construction. These structures are often associated with potential hydrological benefits, including flood attenuation and drought mitigation. Previous research has largely focused on the general hydrological response of beaver dam systems, often treating the dam as a 'black box' without sufficiently considering how specific dam characteristics may influence different hydrological outcomes. This study presents the results from a systematic series of controlled laboratory testing using a hydraulic flume and model beaver dams to investigate the effects of dam type, breach area, and discharge on steady-state pond depth. The model dams were designed to encompass the range of dam types and breach areas commonly observed in natural beaver dams, as reported in previous field studies. The results revealed a diverse range of pond depth responses across the four dam types examined. In general, dam type exerted a greater influence on pond depth under conditions of low discharge and high breach area, while its impact was minimal under conditions of high discharge and low breach area. The findings demonstrate that beaver dams have the capacity to mitigate against flooding; however, this effect is variable and strongly dependent on dam type. These findings underscore the importance of considering dam type, breach area, and discharge as critical variables in assessing the hydrological effects of beaver damming, particularly in relation to mitigation of hydrological extremes.

Much of our knowledge about the phytoremediation potential of floating treatment wetlands (FTWs) comes from studies focusing on the removal of single pollutants, often by a single plant species. Here, we quantify the potential of FTWs planted with varying proportions of the emergent monocots Typha latifolia, Glyceria maxima, and Phragmites australis to simultaneously remove a suite of eleven nutrient/metalloid pollutants. Pollutants most readily removed from water included total inorganic nitrogen (TIN), K and Mn, whilst P, Zn and Cu showed a moderate removal efficiency, and Mg, Ca, Na, Cr, and Fe were poorly removed. Root length within a FTW was correlated with lower concentrations of Ca, Mg, K, P, and Zn remaining in the water, whilst plant uptake and tissue sequestration was more important for reducing concentrations of Mn, TIN, P, and Fe. The effect of community composition over time was greatest for the removal of Zn, with FTWs containing T. latifolia having the strongest effect; community type was less important for the removal of TIN, Mg, K, and Na. Plant tissue sequestration was important for reducing concentrations of Mn, TIN, P and Fe in the water, with median uptake values all greater than 12.5%. Importantly, the removal of some pollutants (e.g., Cu) increased with retention time. Therefore, depending on the management objective, FTWs generally perform better where and when residence times are longer e.g., in ponds or streams under low flow, and assembling FTW communities with varying traits and associated removal mechanisms can allow several pollutants to be remediated at once.

Interactions between species influence ecosystem functions and are sensitive to reintroductions. Our understanding of interactions between naturally co-occurring large herbivores, such as Eurasian beaver (Castor fiber) that are now re-establishing throughout their range, and well-established native ungulates, is limited, despite the potential implications for riparian woodlands. Observations in Scotland indicate that roe deer (Capreolus capreolus) readily exploit the regenerative secondary shoots produced after tree felling by beaver. Our study, based in eastern Scotland, investigates the role of beaver herbivory in riparian woodland regeneration and asks whether deer are attracted to this novel resource because it is either a) more readily available, b) nutritionally superior, or c) morphologically more appealing than accessible browse on unfelled (standing) trees. We firstly quantified the secondary shoots available to browsing deer at different heights on felled and standing birch (Betula spp.) trees in twenty riparian woodland plots across five well-established beaver territories (occupancy ten years). Shoots from birch and willow (Salix spp.) trees with contrasting levels and combinations of beaver and deer browsing were then analysed for nutritional content (nitrogen and carbon) and morphological characteristics (number of buds and lateral branches). We found that 62% of beaver-felled trees produced secondary shoots available to browsing deer. Compared to standing trees, regenerating beaver-felled trees had 18% more secondary shoots. These shoots were significantly higher in nitrogen content (+13%), but similar in carbon content and concentrated closer to the ground. Our results show that beaver herbivory can promote riparian woodland regeneration and heterogeneity by creating a mosaic of mature and multi-stemmed coppiced trees. The addition of a common, readily available, and nutritious resource through beaver browsing could, however, also enhance habitat quality for browsing deer, with the potential to affect deer distribution and feeding habits.

Rewilding presents a unique opportunity to better understand the processes influencing ecological communities and how they function. Although empirical evidence on the effects of rewilding is growing rapidly, knowledge gain is unbalanced, particularly for invertebrates, despite this group representing a large proportion of biodiversity and being fundamental to key ecosystem processes. Here, we advocate for more targeted systematic monitoring and experimental research, providing a site‐based framework for practitioners to evaluate project effects on invertebrate biodiversity. This framework utilizes taxonomic indicators of change, representative of processes important to ecosystem functioning. Implementation of this framework and the associated opportunities and challenges for practitioners are discussed. Adopting this framework would broaden the taxonomic groups and ecosystem processes evaluated by rewilding projects, transform the sector from opinion‐based to evidence‐based, and help address some of the most pressing ecological and conservation questions of the twenty‐first century.

Shallow lake restoration typically focusses on the re‐establishment of macrophytes. The likelihood of a species returning to a site is contingent on dispersal, proximity to propagule sources, and the on‐site propagule‐bank viability. We explore the potential of palaeoecological records in combination with botanical surveys and distribution maps, to ascertain the loss of three submerged macrophytes ( Littorella uniflora , Najas flexilis , and Elatine hydropiper ) from, respectively, two lakes (Barton Broad, Norfolk and Esthwaite Water, Cumbria) and one lake landscape (Greater Glasgow, Scotland). We discuss re‐establishment likelihood when accounting for species' autoecology and current water‐chemistry conditions. L. uniflora is widespread in the United Kingdom but absent locally in Norfolk without known seed bank, hence is unlikely to naturally recolonise Barton Broad. Furthermore, current conditions are unsuitable for this species suggesting that nutrient reduction is required prior to translocation. N. flexilis is extinct in Cumbria and the long distances involved (>100 km) for recolonisation of Esthwaite Water suggest that spatial dispersal is unlikely, rendering the seed bank the last chance of natural recovery. Alternatively, translocation may be feasible. E. hydropiper is a nationally scarce species in the United Kingdom yet would have only a short dispersal distance (~10 km) to recolonise Loch Libo, hence there being no requirement for translocation. In exploring the recovery possibilities for the three focal plant species, we develop a time–space integrated framework that can be employed to guide conservation decisions for other species, enabling a more rational use of translocations in the future, in line with international guidelines.

Environmental DNA (eDNA) metabarcoding is transforming biodiversity monitoring in aquatic environments. Such an approach has been developed and deployed for monitoring lake fish communities in Great Britain, where the method has repeatedly shown a comparable or better performance than conventional approaches. Previous analyses indicated that 20 water samples per lake are sufficient to reliably estimate fish species richness, but it is unclear how reduced eDNA sampling effort affects richness, or other biodiversity estimates and metrics. As the number of samples strongly influences the cost of monitoring programmes, it is essential that sampling effort is optimised for a specific monitoring objective. The aim of this project was to explore the effect of reduced eDNA sampling effort on biodiversity metrics (namely species richness and community composition) using algorithmic and statistical resampling techniques of a data set from 101 lakes, covering a wide spectrum of lake types and ecological quality. The results showed that reliable estimation of lake fish species richness could, in fact, usually be achieved with a much lower number of samples. For example, in almost 90% of lakes, 95% of complete fish richness could be detected with only 10 water samples, regardless of lake area. Similarly, other measures of alpha and beta-diversity were not greatly affected by a reduction in sample size from 20 to 10 samples. We also found that there is no significant difference in detected species richness between shoreline and offshore sampling transects, allowing for simplified field logistics. This could potentially allow the effective sampling of a larger number of lakes within a given monitoring budget. However, rare species were more often missed with fewer samples, with potential implications for monitoring of invasive or endangered species. These results should inform the design of eDNA sampling strategies, so that these can be optimised to achieve specific monitoring goals.

Freshwater biodiversity is declining at unparalleled rates, but fundamental questions remain over how it is distributed at the spatial scales most relevant for conservation management. Here, we test the hypothesis that freshwater biodiversity is distributed across standing waterbody types in a pattern that is reproducible across disparate biota and contrasting landscapes, such that conservation efforts can be aligned across landscapes and taxa. We analysed the richness, composition and distribution of macrophytes, molluscs, beetles and odonates from 199 standing waterbodies (lakes, ponds, ditches and canals) nested within UK landscapes with contrasting dominant land use (agricultural, upland and suburban). We found a common pattern in the distribution of our biodiversity indicators across waterbody types in all landscapes that was largely repeated across biota; lakes consistently had the highest or equal alpha diversity and supported a greater proportion of the sampled species pool in each landscape (mean = 86

The growing focus on the threat of invasive non-native species (INNS) in international biodiversity targets highlights a need for targeted research to support effective understanding, legislation, and management. However, the publishing landscape of invasion biology is complex and expanding rapidly, making consolidation of information increasingly challenging. To identify the major research themes in the INNS literature and to understand how these have changed over the last 35 years, we applied a topic modelling approach. We analysed approximately 10,000 peer-reviewed article abstracts to identify 50 key topics being discussed in the literature. We also quantified how publications on these topics changed over time and how commonly different topics interacted within articles as a measure of their connectedness. Topics covering Population genetics, Policy, First records and Insect biocontrol were the most frequent. Topics were grouped into broad themes, with the largest theme related to Ecosystems, followed by Monitoring, then Management and decision-making. Significant overrepresentation for particular geographical regions and taxa in the literature were apparent. Considering relative changes through time, the most prevalent topics in each decade reflected policy influences, and technological developments. When assessing the degree of connectedness- Policy , Population Genetics and Management Strategies showed low levels of co-occurrence with other topics. This is of particular concern for topics focussed on Policy and Management Strategy as it suggests a weakness at the science-policy interface around accessing and exchanging of evidence. If progress towards future global targets is to be made, we argue that more interdisciplinary research must be encouraged, in particular to better incorporate policy and management considerations into the wider research landscape.

Phytoremediation using floating treatment wetlands (FTWs) is an emerging nature-based solution for freshwater restoration. However, the potential to design these systems by manipulating macrophyte community composition to provide multiple ecosystem services remains unexplored. Using a tank experiment, we simulated aquatic environments impacted by multiple pollutants and employed a comparative ecological approach to design emergent macrophyte communities using the trait of plant stature (plant height) to structure communities. Ecosystem functions were quantified, and a threshold-based method used to compute an ecosystem multifunctionality index that was weighted based on three different management-driven restoration objectives: equal importance, phytoremediation, and regulation and cultural services. Across all restoration scenarios, ecosystem multifunctionality was higher when community types performed more diverse functions. Small emergent plant communities outperformed all other community types due to their increased provision of both regulation and maintenance, cultural, and provisioning services. Conversely, large emergent communities that are more typical candidates for phytoremediation had the highest levels of multifunctionality only when function was lower. Arranging emergent macrophytes in mixed-statured communities led to intermediate or poorer performance both in terms of multifunctionality and specific functions, suggesting that diversity on the plant stature axis leads to negative plant interactions and represents a ‘worst of both worlds’ combination. Employing comparative ecology to generalise plant selection by stature demonstrates that large emergent macrophytes are more likely to better deliver provision-based services, while small emergent communities can provide additional benefits from cultural and regulatory services. Selecting macrophytes for FTWs employed in freshwater restoration by stature is a simple and widely applicable approach for designing plant communities with predictable outcomes in terms of (multiple) ecosystem service provision and highlights the need for environmental managers to closely align restoration objectives with potential community types.

Phytoremediation using floating treatment wetlands (FTWs) is an emerging nature-based solution for freshwater restoration. However, the potential to design these systems by manipulating macrophyte community composition to provide multiple ecosystem services remains unexplored. In a mesocosm experiment simulating a diffuse pollutant impacted water environment we employed a comparative ecological approach to design emergent macrophyte communities using the trait of plant stature to structure communities. Ecosystem functions were quantified, and a threshold-based method used to compute an ecosystem multifunctionality index that was weighted based on three different management-driven restoration objectives: equal importance, phytoremediation, and regulation and cultural. Across all restoration scenarios, ecosystem multifunctionality was higher when community types performed more diverse functions. Small-emergent communities outperformed all other community types due to their increased provision of both regulation and maintenance, cultural, and provisioning services. Conversely, large emergent communities that are more typical candidates for phytoremediation had the highest levels of multifunctionality only when function was lower. Arranging emergent macrophytes in mixed-statured communities leads to intermediate or poorer performance both in terms of multifunctionality and specific functions suggesting that diversity on the plant stature axis leads to negative plant interactions and represent a ‘worst of both worlds’ combination. Employing comparative ecology to generalise plant selection by stature demonstrates that large emergent macrophytes are more likely to perform better at delivering provision-based services, while small emergent communities can provide additional benefits from cultural and regulatory services. Selecting macrophytes for FTWs employed in freshwater restoration by stature (plant height) is a simple and widely applicable approach for designing plant communities with predictable outcomes in terms of (multiple) ecosystem service provision. These results highlight the need for environmental managers to closely align restoration objectives with community type selection and understand the trade-offs between selecting for the provision of many services at a lower performance level (generalist plant community), or fewer services at a higher performance level (specialist plant community).

Flow regulation is a prolific and growing influence on rivers world-wide. Nine cascade hydropower dams were constructed along the 1,150-km Wujiang River in China over the past 30 years, disrupting longitudinal continuity. Water level fluctuations in the associated reservoirs range between daily, weekly, seasonal, and annual, depending on the type of regulation, but the comparative impacts of these regimes on plant growth strategies, or the extent of their downstream influence, is unknown. Competitor, stress-tolerator, and ruderal (CSR) plant strategies were used to assess the impact of reservoir regulation type on the riparian herbaceous plant community based on sampling the inundation zone of nine reservoirs and their downstream river reaches during 2017 and 2018. Our results revealed profound differences in CSR plant strategies of the dominant vegetation with respect to water level regime. While ruderal plants dominated (45%-60% of species), irrespective of regulation type, vegetation in reservoirs exhibited a strong shift from stress-tolerators (e.g., Cynodon dactylon, C-11.9:S-41.5:R-46.5%) to competitors (e.g., Reynoutria japonica, C-77.9:S-0:R-22.0%) with increasing intensity of water level fluctuation, reflecting the shift from annual to daily regulation. The width of the inundation zone was the best overall variable in explaining the CSR strategies of riparian vegetation, both in the reservoir inundation zone (r(2)-adj = 15.4%) and the downstream river (r(2)-adj = 7.3%). Retention time significantly explained variation in CSR plant strategies in the reservoir inundation zone (r(2)-adj = 3.7%, p = 0.002) but not downstream (p > 0.01). There was also a clear scale dependency of CSR plant strategies, with an increase in stress tolerators (average slope = 0.7%/km) and decline of competitor (average slope = -0.3%/km) and ruderal plants (average slope = -0.9%/km) with increasing distance downstream from dams. The growth strategies of the dominant riparian vegetation changed with the magnitude and frequency of water level fluctuations caused by differences in regulation type, and local environmental conditions. Clear scale dependency in the CSR plant strategies was observed with distance from the dam, with ruderals dominating closest to the reservoirs and declining gradually downstream as stress tolerators increased. Our study helps to evaluate the impact of river damming on the functional traits of riparian vegetation and to predict the resilience and restoration potential of riparian vegetation under different forms of human disturbance.

Global water security is critical for human health, well-being, and economic stability. However, freshwater environments are under increasing anthropogenic pressure and now, more than ever, there is an urgent need for integrated approaches that couple issues of water security and the remediation of degraded aquatic environments. One such strategy is the use of floating treatment wetlands (FTW), which are artificial floating mats that sustain and support the growth of macrophytes capable of removing nutrients from over-enriched waterbodies. In this study, we quantify a range of indicators associated with FTWs, planted with different vegetation community types (i.e., monocultures and polycultures) over the course of a three-year field-scale study. The composition of the two different types of FTWs changed significantly with a convergence in diversity and community composition between the two types of FTWs. Phytoremediation potential of the two FTW communities, in terms of nutrient standing stocks, were also similar but did compare favourably to comparable wild-growing plant communities. There were few substantial differences in invertebrate habitat provision under the FTWs, although the high incidence of predators demonstrated that FTWs can support diverse macroinvertebrate communities. This field-scale study provides important practical insights for environmental managers and demonstrates the potential for enhanced ecosystem service provision from employing nature-based solutions, such as FTWs, in freshwater restoration projects.