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Biofilms are considered a basal resource with high nutritional quality in stream food webs, as periphytic algae are abundant of polyunsaturated fatty acids (PUFAs). PUFAs are essential for growth and reproduction of consumers who cannot or have very limited capacity to biosynthesize. Yet, how the nutritional quality based on PUFA of basal food sources changes with light intensity remains unclear. We conducted a manipulative experiment in mesocosms to explore the response and mechanisms of nutritional quality to shading, simulating riparian restoration. We found a significant increase in PUFA% (including arachidonic acid, ARA) under shading conditions. The increased PUFA is caused by the algal community succession from Cyanobacteria and Chlorophyta to Bacillariophyta which is abundant of PUFA (especially eicosapentaenoic acid, EPA; docosahexaenoic acid, DHA). On the other hand, shading increased PUFA via upregulating enzymes such as Δ12 desaturase (FAD2, EC:1.14.19.6) and 3-ketoacyl-CoA synthase (KCS, EC:2.3.1.199) in the biosynthesis of unsaturated fatty acid elongation pathways. Our findings imply that riparian reforestation by decreasing light intensity increases the nutritional quality of basal resources in streams, which may enhance transfer of good quality carbon to consumers in higher trophic levels through bottom-up effects. [ABSTRACT FROM AUTHOR]

Concern over rising water temperatures for freshwater ectotherms has led to application of experimentally derived thermal thresholds to stream temperature models for estimation of streams at high risk of exceeding thermal thresholds under current and future climate conditions. We optimised an approach that links field‐relevant thermal maxima experiments to corresponding stream temperature models and identifies opportunities to reduce stream temperatures through riparian tree growth.We conducted a thermal maxima experiment on cold‐water adapted juvenile Chinook (Oncorhynchus tshawytscha) and coho salmon (Oncorhynchus kisutch) that reflected natural temperatures by using incremental temperature ramping with diel fluctuations (IT‐Dmax) and refit a regionally specific stream temperature model for British Columbia, Canada to directly relate to lab‐derived thresholds. Salmon‐bearing streams across British Columbia were categorised by threshold exceedance risk (i.e., low, moderate, high, severe) based on risk tolerance scenarios for management decision making (i.e., considering a range of prediction intervals [PIs] and stream thermal sensitivities to air temperature). We linked these results directly to riparian management and restoration actions by estimating the potential for riparian tree growth to reduce threshold exceedance risk.Lab‐derived IT‐Dmax endpoints were consistently 24°C (based on the median value between the 7‐day average of the daily maximum and the mean weekly average temperature) across acclimation treatments for both species. Under current conditions, most stream reaches (99.6% using an intermediate risk tolerance scenario) were below the thermal threshold; streams with moderate to high risk of threshold exceedance were projected to increase from 0.4% to 1.5% (total linear stream length of 6,929 km) by end of century. The risk‐averse (high sensitivity, 75% PI) and risk‐tolerant (low sensitivity, 95% PI) scenarios differed by 1,107 km of streams predicted to have a moderate to severe risk of exceeding thresholds by end of century. Maximal riparian tree growth was predicted to shift 670 km of streams from moderate to low exceedance risk under end‐of‐century conditions and intermediate risk tolerance, showing the potential for mitigation from thermal impacts.Our integrative approach tackled several key considerations in identifying streams at high temperature risk for freshwater ectotherms that to date have not been addressed. Furthermore, we showcased the delineation of spatially comprehensive estimates that identify where management mitigation and a specific restoration activity may be most needed to reduce impacts of rising temperatures on rearing salmonids across an extensive region. [ABSTRACT FROM AUTHOR]

The New Mexico Jumping Mouse (Zapus luteus) is a federally endangered granivore active for only 3 to 5 months annually. Knowledge of diet can help guide habitat recovery and yet despite calls for restoration of its riparian habitat, the diet of Z. luteus remains largely unknown. To date, only 8 plant species have been described in the diet—whereas insectivory, mycophagy, and dietary shifts have only been hypothesized. In the late summer, Z. luteus rapidly accumulates fat for a 9-month hibernation and restoration may fail if seasonal variation in the diet is overlooked. We used DNA metabarcoding on fecal DNA (n = 165) to resolve dietary taxa within multiple trophic levels of the diet and investigate monthly patterns of consumption. Seldom studied in metabarcoding frameworks, we also investigated exogenous contamination in Sherman live-capture traps. Potential contamination among feces, pelage, and trap surfaces was detectable but low (median = 0% to 2%), with fecal communities distinct from exogenous sources. The diet of Z. luteus was varied and most frequently (frequency of occurrence) of graminoids, forbs, lepidopterans, dipterids, and false-truffles. For plant foods, dietary diversity increased throughout their season of activity, shifting from sedges and woody vegetation in the early season (June to July) to forbs and grasses in the late season (August to September). Insect consumption was consistently detected throughout the season, whereas mycophagy was more frequently detected in August, when hypogeous fungi are typically more abundant. The breadth of dietary taxa suggests plasticity in resource use, potentially accommodating diverse patterns of seed availability throughout their active period. Shifts in plant consumption may reflect a dietary adaptation to the phenological patterns of their plant communities, a synchrony that might benefit both pre- and post-hibernation survival. Our work substantially improves our understanding of the diet of Z. luteus (241 dietary taxa) and will be useful for guiding habitat recovery. It also offers scalable methods to further investigate the diet under disturbance contexts (e.g. grazing, wildfire, drought). [ABSTRACT FROM AUTHOR]

The rupture of the Fundão dam (Brazil) spread tailings contaminated with sodium and ether-amine into the Doce River Basin. Aiming at rehabilitating a contaminated riparian site, phytoremediation with native species of the Atlantic Forest was performed under four treatments: ES-1: physical remediation (sediment scraping) + chemical remediation (organic matter) + bioremediation (double inoculation with the arbuscular mycorrhizal fungus (AMF) Rhizophagus irregularis and the plant growth-promoting bacteria Bacillus subtilis); ES-2: chemical remediation + bioremediation; ES-3: physical remediation + chemical remediation; ES-4: chemical remediation. Ether-amine and sodium contents, plant growth and, soil quality parameters were compared among treatments and relative to preserved and degraded sites. Two years after planting, the outstanding plant growth was attributed to the phytoremediation of ether-amine and ammonium, followed by a significant increase in soil microbial biomass (Phospholipid fatty acids-PLFAs), particularly the Gram+ bacteria and total fungi but not AMF, whose response was independent of the inoculation. While sodium and ether-amine declined, soil K, P, NO3− contents, dehydrogenase and acid phosphatase activities, cation exchange capacity (CEC) and soil aggregation increased, especially in ES-1. Thus, such remediation procedures are recommended for the restoration of riparian areas affected by the Fundão tailings, ultimately improving sediment fertility, aggregation and stabilization. To the best of our knowledge, this is the only successful example of fragment of riparian Atlantic Forest successfully rehabilitated using native trees from the Atlantic Forest in the riparian zone affected by the contaminated Fundão dam tailings. For that, phytoremediation and bioremediation procedures were adopted to alleviate etheramine and sodium toxicity, resulting in the amelioration of soil fertility and particularly the stabilization of such highly disaggregated sediments, ultimately protecting the Doce river basin against these contaminants. [ABSTRACT FROM AUTHOR]

Riparian ecosystems are valuable habitats for bats, due to high densities of emergent aquatic invertebrates that provide high-quality feeding areas. Throughout Europe, decline and extirpation of European beaver (Castor fiber) has been a key driver in the decline of the extent and quality of riparian habitat, and thus recolonisation has considerable potential to restore degraded areas. Previous research has shown that beaver-modified ecosystems can support more bats, but the assumed causal link (an increase in invertebrate prey) has not been tested. Here, we study bat activity and richness/abundance of aquatic macroinvertebrates at a site where free-roaming beavers have colonised naturally from a nearby (unofficial) release location versus a nearby control site with very similar hydrology and habitat matrix. Bat activity was recorded using walked activity transects and fixed-point acoustic detectors. Although bat species richness was similar, bat activity was substantially and significantly higher at the beaver site versus the control site overall (42.7%) and for four specific taxa: soprano pipistrelle (Pipistrellus pygmaeus; 8.4%), Daubenton's (Myotis daubentonii; 46.5%), common pipistrelle (Pipistrellus pipistrellus; 110.4%) and common noctule (Nyctalus noctula; 170.9%). Richness of the larvae/nymphs of emergent aquatic macroinvertebrate species known to form an important part of bat diet was 205.5% higher at the beaver site compared to the control site, while abundance was 817.4% higher. Overall bat activity was also linked to habitat (lotic > lentic), survey method (transect > fixed-point), and season (May–July peak). This is the first evidence of a likely causal link between beaver recolonisation and bat activity via an increase in abundance of key aquatic invertebrate prey and we recommended that benefits of beaver reintroduction on bats be considered in future feasibility studies. [ABSTRACT FROM AUTHOR]

Dissolved organic matter (DOM) is one of the active soil carbon fractions. The characteristics of DOM in the riparian zone are closely related to the occurrence of eutrophication. However, there is no scientific consensus on how flooding intensity on DOM distribution in the riparian zone of the Three Gorges Reservoir (TGR). In this study, 99 soil riparian samples were collected from three water level elevations (145–155 m asl, 155–165 m asl and 165–175 m asl) in both mainstream and tributaries of the Yangtze River within the TGR. DOM characteristics were investigated using ultraviolet–visible absorption spectra and three‐dimensional fluorescence excitation–emission matrix‐parallel factor analysis as well as principal component analysis (PCA). The result showed that dissolved organic carbon (DOC), absorption coefficient at 254 nm (a254), absorption coefficient at 350 nm, specific ultraviolet absorbance at 254 nm (SUVA254), and humification index (HIX) decreased while freshness index (β:α) and biological index (BIX) increased with the decline of the water level elevations. The trend in the DOM characteristics along the riparian zone was mainly attributed to the variation in the bioavailability of DOM and fluorescence components (C1, C3 and C4). Overall, our study highlights the newly formed DOM during the dry season, indicated by β:α and BIX, might be more accumulated at the lower elevation. Furthermore, because of the greater lability during the reservoir impoundment, the newly formed DOM can be easily utilized by algae and may raise water eutrophication under re‐flooding and longer flooding, thus enforced strategic mitigation measures could help to achieve the goal of riparian restoration in TGR. [ABSTRACT FROM AUTHOR]

The initiation of a new plant community in a restoration area hinges on the performance of seedlings post-planting. This study aimed to evaluate the impact of species functional traits—specific leaf area (SLA), wood density (WD), seed dry mass (SDM), and potential height (H)—on the seedling performance 25 months after planting, comparing two planting designs (rows and clusters) and the influence of fertilization addition in clusters. The restoration area is a riparian tropical forest located on the coastal plain at Caraguatatuba municipality, São Paulo, Brazil. We monitored 3017 tree seedlings and estimated their survivorship and relative growth rate (RGR) using the diameter, height, and canopy area of the surviving seedlings and the stem biomass for the cluster RGR estimation. Using linear mixed models, we analyzed how the planting designs and the functional traits affect species survival and their RGR. We underscored the significance of slow-growth traits (low SLA, and high SDM and WD) in enhancing species survival, whereas, maximizing species growth entails prioritizing seedlings with greater potential height. Cluster survival and growth improved with a greater abundance of species with low values of SDM (i.e., fast-growth species) and communities with low functional divergence (high similarity). Fertilized clusters improved the RGR of large-seeded species. Accounting for functional traits in restoration is advantageous for enhancing seedling performance at the species level, which is an important consideration for restoration practitioners. To optimize applied nucleation, clusters should target functional diversity at this community level and include competitive species to improve productivity. [ABSTRACT FROM AUTHOR]

Riparian areas can be highly biodiverse and provide critical ecosystem services. However, they are frequently subject to anthropogenic impacts such as land clearing, agricultural use, and urban development. Restoration of riparian areas via revegetation commonly improves the health of waterways and surrounding areas, but vegetation outcomes are rarely assessed. Our study compared 10 to 14‐year‐old revegetation to remnant vegetation in riparian areas of south‐eastern Australia to determine if species composition, vegetation structure, and ecosystem function (plant recruitment) differed. We also assessed if the amount of surrounding native vegetation, browsers (including deer, rabbits, and macropods), or soil characteristics influenced native woody plant recruitment at revegetated sites. While native and exotic woody species richness did not differ, native woody plants were less abundant and exotic woody plants twice as abundant at revegetated sites. The ground layer of revegetated sites was dominated by weeds, whereas remnant sites largely comprised native herbaceous plants and leaf litter. Tree heights and tree canopy cover were similar in revegetated and remnant areas, although shrubs and ferns were lacking in revegetation. Native woody plant recruitment was lower at revegetated sites and was negatively associated with browser presence. Our results suggest that while revegetation may have similar species richness and tree cover as remnant areas, weeds often dominate and important structural components such as shrubs and ferns, and ecological processes such as plant recruitment, are lacking. Better consideration of all vegetation strata, reduced browsing pressure and weed control are likely to achieve better revegetation outcomes. [ABSTRACT FROM AUTHOR]

Dry tropical forests are unique, biodiverse ecosystems threatened by human development, especially deforestation for agricultural land use. Deforestation reduces carbon sequestration in landscapes and, in turn, pollutes nearby waterways. Agroforestry practices, like silvopastoralism, can mitigate these impacts by integrating trees into working landscapes, but their effect on stream water quality has not been studied. We assessed the stream condition on five silvopastoral farms in Panama's Azuero Peninsula by utilizing aquatic macroinvertebrates as indicators. We collected aquatic macroinvertebrates and calculated the percent EPT, Diptera, and Odonata. Using ArcGIS, we measured distance to live fence, riparian connectivity, and forest patch size. We also measured tree carbon stored in the riparian area and throughout each farm. We analyzed the relationships between landscape or habitat variables and water quality scores using single linear regressions in R Studio. Percent EPT, Odonata, and diversity were positively predicted by riparian tree carbon, while percent Diptera was negatively predicted by riparian tree carbon. Our results highlight the importance of expanding agroforestry in this region and suggest that increasing tree cover in agricultural landscapes may be beneficial to stream condition, but additional research is needed. [ABSTRACT FROM AUTHOR]

It is a widely discussed topic in restoration ecology to use organic carbon (OC) management to increase nutrient uptake in chronically loaded agricultural streams. However, although nitrate uptake has been shown to correlated closely with the availability of dissolved OC, this relationship is less clear for phosphate. Likewise, the role of particulate OC (POC) on stimulating nutrient uptake has to be clarified. We aimed at investigating the effects of leaf additions on the net uptake of soluble reactive phosphorus and nitrate‐nitrogen from the water column by benthic biofilms in combined laboratory flume and batch experiments.Fine sediments were colonised under nutrient‐enriched conditions in the dark (dark‐grown heterotrophic biofilms) and under a 12/12‐hr dark/light cycle (light‐grown photoautotrophic biofilms) in flumes. In each light treatment, half of the biofilms were grown under strong OC‐limitation, the other half under near‐optimal C:N:P ratios. For the uptake experiments, the colonised sediments were incubated in nutrient‐enriched water to which (1) fresh alder leaves, (2) pre‐leached leaves, or (3) no leaves were added. Net nutrient uptake (or release) rates were determined via the change in nutrient concentrations in the water column over time.Net phosphorus uptake by dark‐grown biofilms was significantly increased by the addition of leaves. Despite their high initial nutrient leaching, fresh leaves showed stronger stimulating effects on the net P uptake than leached leaves over the entire experiment. Furthermore, biofilms grown under near‐optimum C:N:P ratios responded stronger to the POC supply than biofilms grown under C‐limited conditions. In contrast to dark‐grown biofilms, leaf additions had no significant effects on the net P uptake by light‐grown biofilms. We also found no effects of leaf additions on net nitrate uptake.Our study shows that an increased POC supply in nutrient‐impacted streams may boost heterotrophic phosphate uptake. However, the stimulating effect of the POC addition depends on a variety of POC‐dependent (e.g. respiration, heterotrophic assimilation, denitrification) and independent (e.g. adsorption, photoautotrophic assimilation) processes, making nutrient control via POC management challenging. We suggest application of management approaches that focus on restoration of riparian areas and wetlands to increase the amount of natural, complex POC with a moderate degradability, thus keeping the heterotrophic metabolism low but potentially stimulating in‐stream N and P retention. [ABSTRACT FROM AUTHOR]

Effective ecological restoration requires empirical assessment to determine outcomes of projects, but conclusions regarding the effects of restoration treatments on the whole ecosystem remain rare. Control of invasive shrubs and trees in the genus Tamarix and associated riparian restoration in the American Southwest has been of interest to scientists and resource managers for decades; dozens of studies have reported highly variable outcomes of Tamarix control efforts, as measured by a range of response variables, temporal and spatial scales and monitoring strategies. We conducted a literature search and review, meta-analysis and vote count (comparison of numerical outcomes lacking reported variances and/or sample sizes) on published papers that quantitatively measured a variety of responses to control of Tamarix. From 96 publications obtained through a global search on terms related to Tamarix control, we found 52 publications suitable for a meta-analysis (n = 777 comparisons) and 63 publications suitable for two vote counts (n = 1,460 comparisons total; 622 comparisons reported as statistically significant) of response to Tamarix control. We estimated responses to control by treatment type (e.g. cut-stump treatment, burning, biocontrol) and ecosystem component (e.g. vegetation, fauna, fluvial processes). Finally, we compared results of the various synthesis methods to determine whether the increasingly stringent requirements for inclusion led to biased outcomes. Vegetation metrics, especially measures of Tamarix response, were the most commonly assessed. Ecosystem components other than vegetation, such as fauna, soils and hydrogeomorphic dynamics, were under-represented. The meta-analysis showed significantly positive responses by vegetation overall to biocontrol, herbicide and cut-stump treatments. This was primarily due to reduction of Tamarix cover; impacts on replacement vegetation were highly variable. We found concordance amongst our varied synthesis approaches, indicating that increased granularity from stricter quantitative techniques does not come at the cost of a biased sample. Overall, our results indicate that common control methods are generally effective for reducing Tamarix, but the indirect effects on other aspects of the ecosystem are variable and remain understudied. Given that this is a relatively well-studied invasive plant species, our results also illustrate the limitations of not only individual studies, but also of reviews for measuring the impact of invasive species control. We call on researchers to investigate the less commonly studied responses to Tamarix control and riparian restoration including the effects on fauna, soil and hydrogeomorphic characteristics. [ABSTRACT FROM AUTHOR]

Disentangling the underlying processes of plant adaptations to multiple abiotic stressors is crucial regarding promissory species for the restoration of riparian ecosystems prone to suffering extreme flood and drought events in the context of global climate change and human activities. Distylium chinense is a dominant evergreen shrub, distributed in the riparian areas of the Yangtze River in China. Here, one field study and five controlled experiments (Control, CK; single drought, D; single flooding, FF; from drought to recovery to full flooding, D-R-FF; from full flooding to recovery to drought, FF-R-D) were conducted. More hypertrophied lenticels, adventitious roots, and the increased stem-base hypertrophy of D. chinense were observed under the D-R-FF condition compared with FF and FF-R-D. Interestingly, the increase of the net photosynthetic rate (Pn) coincidentally occurred with the increase of heme degradation by heme oxygenase (r = 0.608, p = 0.003). Pn of D. chinense in D-R-FF was about twice as much as that in FF-R-D. The enhanced photosynthetic performance was functionally coupled with the adequate water supply to promote the tolerance of D. chinense to alternate drought–flooding condition compared with no any flooding condition. The accumulation of soluble sugar was highest under D, followed by FF-R-D, FF and D-R-FF, which showed that soluble sugar accumulation over the drought period could trigger the recovery growth of flooded plants in later flooding. These data provided the first insights into the tolerance mechanisms by a suite of morphological alterations and physiological adaptations, especially in the enhanced photosynthetic performance of D. chinense under alternating drought and flooding stresses. So, D. chinense could be considered as a prominent shrub species in the restoration practices of wetlands, riparian areas, and other flood-prone forests. [ABSTRACT FROM AUTHOR]

Plant–plant interactions under extreme environmental stress are still controversial. The stress gradient hypothesis (SGH) proposes that facilitation prevails under extreme environmental stresses, while an alternative view states that facilitation collapses or even switches back to competition at the extreme end of stress gradients. However, how the relationship between plant–plant interaction and periodic extreme flooding stress varies and its underlying mechanism are still unclear in a dam-regulated riparian ecosystem. We established a controlled experiment using two dominant species pairs (Cynodon dactylon–Cyperus rotundus and C. dactylon–Xanthium sibiricum) in the water level fluctuating zone of the Three Gorges Dam to examine their growth responses to the periodic extreme flooding stress. The results showed that as flooding stress increased, the competitive effect of C. dactylon on X. sibiricum shifted to facilitation, whereas the effect of X. sibiricum on C. dactylon maintained a strong inhibition. The plant height of X. sibiricum was the most important driver of the interaction between X. sibiricum and C. dactylon along the flooding gradient. The net effect of C. dactylon on C. rotundus shifted from neutral to negative, and the inhibitory effect of C. rotundus on C. dactylon became stronger at the extreme end of flooding stress. The root biomass of the two species was the key trait regulating their interaction with increasing flooding stress. Overall, the SGH was partially supported along our periodic extreme flooding stress gradient. Aboveground resource (light) might be the dominant factor driving the response of the interaction between annual plants and perennial clonal plants to periodic flooding stress, whereas belowground resource (water and nutrients) was probably the dominant factor for perennial clonal plants. Our study will help to further understand the environmental responses of plant–plant relationships and their regulatory mechanism, and the succession of riparian plant communities under extreme environmental changes, providing a basic theoretical basis and data support for the ecological restoration and management of riparian wetland vegetation. [ABSTRACT FROM AUTHOR]

Vegetation cover and land use are important factors related to the capacity of ecosystems to provide soil loss regulation and sediment retention services, which are highly relevant for sediment management in watersheds draining into reservoirs with multiple water uses. One way to ensure the protection and recovery of vegetation by landowners in Brazil is the implementation of the federal Native Vegetation Protection Law (NVPL), which designates environmentally sensitive areas as Areas of Permanent Preservation (APPs), aiming to conserve water resources and prevent soil erosion. The benefits of riparian vegetation in the catchment of Corumbá IV Hydroelectric Power Plant (HPP), located in the Brazilian Cerrado, were analyzed considering landscape reconfigurations from a baseline condition (year 2011) in order to account for the recovery of riparian vegetation by the agricultural sector, as foreseen in the NVPL. The Sediment Delivery Ratio (SDR) model from the InVEST (Integrated Valuation of Environmental Services and Tradeoffs) package was used to map and quantify variations in sediment export and sediment retention throughout the catchment. The reduction in annual sediment export in the drainage basin of the Corumbá IV reservoir reached −27% in the scenario where the total deficit of riparian APPs occupied by pasture or agriculture in the baseline map (41.000 ha) are recovered. While 14% of riparian APP are occupied by crops versus 86% occupied by pasture in the drainage basin of the Corumbá IV HPP, the recovery of riparian zones occupied by agricultural activities resulted in the greatest benefits in sediment retention for the reservoir. The methodology employed in this study can support the prioritization of sectoral efforts for the restoration and conservation of native vegetation, considering the highest returns in benefits perceived by water users affected by sediment input in reservoirs. The study's results reinforce the importance of conserving vegetation in riparian areas and their surroundings for sediment retention, highlighting the role of these areas as assets in providing water-related ecosystem services. For future developments, it is suggested to assess the interconnections among the energy, water, and food sectors to better understand the barriers and challenges to the maintenance and improvement of water-related ecosystem services in the catchment area of Corumbá IV HPP. [ABSTRACT FROM AUTHOR]

Human activities and climate change have increased damage to riparian forest and their functions, stimulating interest in riparian restoration research and resulting in a surge of related publications. However, a comprehensive bibliometric analysis of riparian restoration research has been lacking until recently. To understand trends and hotspots in riparian restoration research, we performed a literature search of riparian restoration publications from 1990 to 2022 based on the Web of Science database. We found 2121 peer-reviewed articles, and then each paper was bibliometrically researched, analyzing authors, institutions, countries, citations, journals, publication years, and keywords. The results showed a growing number of annual articles during 1990–2022, but declining average citations. Environmental science, ecology, biodiversity conservation, engineering, and forestry were popular fields in riparian restoration. Publications on the riparian restoration field were widely dispersed in different journals, but Restoration Ecology and Ecological Engineering have higher influence and more publications and citations than other journals. Lorenz A. W., Nilsson C., and Kondolf G. M. were the most competitive authors because of their high number of publications and citations. The USA had the greatest research output and the most citations. American scientists preferred national collaboration, while Switzerland scientists engaged more in international collaborations. Research focus shifted from ecosystems and rivers before the 21st century to management topics after 2001 and biodiversity and conservation after 2011. This study provides valuable insights into the progress of riparian restoration research globally. [ABSTRACT FROM AUTHOR]

With continued anthropogenic inputs of nitrogen (N) into the environment, non-point source N pollutants produced in winter cannot be ignored. As the water-soil interface zones, riparian wetlands play important roles in intercepting and buffering N pollutants. However, winter has the antagonistic effect on the N removal. Substrate improvement has been suggested as a strategy to optimize wetland performance and there remain many uncertainties about the inner mechanism. This study explores the effects of substrate improvement on N removal in winter and rhizospheric crosstalk between reed (Phragmites australis) and microbes in subtropical riparian reed wetlands. The rates of wetland N removal in winter, root metabolite profiles, and rhizosphere soil microbial community compositions were determined following the addition of different substrates (gravel, gravel + biochar, ceramsite + biochar, and modified ceramsite + biochar) to natural riparian soil. The results showed that the addition of different substrates to initial soil enhanced N removal from the microcosms in winter. Gravel addition increased NH4+-N removal by 8.3% (P < 0.05). Gravel + biochar addition increased both TN and NH4+-N removals by 8.9% (P < 0.05). The root metabolite characteristics and microbial community compositions showed some variations under different substrate additions compared to the initial soil. The three treatments involving biochar addition decreased lipid metabolites and enhanced the contents and variety of carbon sources in rhizosphere soil, while modified ceramsite + biochar addition treatment had a greater impact on the microbial community structure. There was evidence for a complex crosstalk between plants and microbes in the rhizosphere, and some rhizosphere metabolites were seen to be significantly correlated with the bacterial composition of the rhizospheric microbial community. These results highlighted the importance of rhizospheric crosstalk in regulating winter N removal in riparian reed wetland, provided a scientific reference for the protection and restoration of riparian reed areas and the prevention and control of non-point source pollution. [ABSTRACT FROM AUTHOR]

Despite long‐standing knowledge of the benefits of riparian buffers for mitigating nonpoint source pollution, many streams are unprotected by buffers. Even landowners who understand ecological values of buffers mow riparian vegetation to the streambank. Do trends in rural riparian conditions reflect the development of riparian forest science? What motivates residential riparian management actions? Using high‐resolution orthoimagery, we quantified riparian conditions and trends between 1998 and 2015 in the rural upper Little Tennessee River basin in Macon County, North Carolina and explored how landowners view riparian zone management and riparian restoration programs. Buffer composition in 2015 was as follows: no buffer (32.5%), narrow (19.3%), forested (26.7%), shrub (7.2%), and intermediate (7.0%). Relative to 1998, the greatest decrease occurred in the no buffer class (−17.7%, 46 km) and the largest increases occurred in the shrub (+72.5%, 20 km) and narrow (12.6%, 14 km) classes. Forested buffer marginally increased. Semi‐structured interview data suggest that landowners prioritize recreational and scenic aspects of riparian buffers over ecological functions such as filtration and bank stabilization. Riparian restoration programs might be made more enticing to non‐adopters if outreach language appealed to landowner priorities, design elements demonstrated intentional management, and program managers highlighted areas where ecological goals and landowner values align. [ABSTRACT FROM AUTHOR]

River ecosystems face growing threats from human‐induced stressors, resulting in habitat degradation and biodiversity loss. Crucial to these ecosystems, macroinvertebrates maintain river health and functioning. In this review, we examine the challenges confronting macroinvertebrates, explore restoration strategies and management approaches, and shed light on knowledge gaps and future research directions. Habitat degradation, water pollution, climate change, and invasive species are discussed as key challenges. Various restoration strategies, such as in‐stream habitat restoration, flow regime restoration, riparian zone restoration, and connectivity restoration, are evaluated for macroinvertebrate conservation. Integrated catchment management, adaptive management, community‐based management, monitoring, and policy integration are highlighted as essential management approaches, and knowledge gaps in long‐term monitoring, innovative restoration techniques, climate change resilience, and policy incorporation are identified as areas calling for further research. Ultimately, a proactive, adaptable, and cooperative approach to river management will ensure macroinvertebrate conservation and sustainable river ecosystems. [ABSTRACT FROM AUTHOR]

Mycorrhizal restoration benefits are widely acknowledged, yet factors underpinning this success remain unclear. To illuminate when natural regeneration might be sufficient, we investigated the degree mycorrhizal fungi would colonize Populus fremontii (Fremont cottonwood) 2 years after the restoration of a riparian corridor, in the presence of an adjacent source. We compared colonization levels across plant populations and ecotypes, and from trees in the planted area to those in natural source populations. Four findings contribute to the theory and application of host–symbiont interactions. (1) Median ectomycorrhizal colonization of trees in the planted area was less than one‐tenth of that within natural source populations (p < 0.05), suggesting that even with adjacent intact habitat, sluggish regeneration would make proactive mycorrhizal restoration beneficial. (2) Within the planted area, median ectomycorrhizal and arbuscule colonization of trees sourced from greater distances were less than one‐third of that for trees sourced locally (p < 0.05), suggesting translocation poses barriers to symbioses. (3) Changes in colonization did not align with plant ecotypes, suggesting that geographic scales of selection for plants and fungi differ. (4) Slight increases in median mycorrhizal colonization (from 0% to 5%) were strongly correlated with increased survival for the plant provenance with lowest survival (r2 = 46% and rs = 48%, p < 0.05), suggesting mycorrhizae are particularly beneficial when plants are under stress (including translocation‐induced stress). This study is novel in demonstrating that mycorrhizal regeneration is slow even in the presence of adjacent intact habitat, and that when colonization could seem negligible, it may still have biological significance. [ABSTRACT FROM AUTHOR]

Riparian systems across the Southwest United States are extremely valuable for the human and ecological communities that engage with them. However, they have experienced substantial changes and stresses over the past century, including non-native vegetation expansion, vegetation die-offs, and increased fire activity. Vegetation management approaches, such as ecological restoration, may address some of these stressors as well as reduce the risk of future impacts. We apply remote sensing to inform restoration priorities along the upper Gila River within the San Carlos Apache Reservation and Upper Gila River watershed. First, we develop a spatially and temporally explicit trend analysis across three observed climate periods (1985–1993, 1993–2014, 2014–2021) using the Landsat-derived indices to quantify changes in riparian vegetation conditions. These maps can be used to identify areas potentially more at risk for degradation. Second, we analyze changes in riparian vegetation within a climate framework to better understand trends and the potential effect of climate change. Vegetation greenness has largely increased throughout the watershed despite intensifying drought conditions across our study period, though areas within the lower watershed have shown increased stress and higher rates of wildfire and other disturbances over the past 5-years. Nevertheless, small-scale restoration activities appear to show improving vegetation conditions, suggesting efficacy of these restoration activities. Results from this study may be integrated with restoration objectives to develop a restoration plan that will help riparian vegetation communities adapt to change.

Rock detention structures (RDS) are used in restoration of riparian areas around the world. The purpose of this study was to analyze the effect of RDS installation on vegetation in terms of species abundance and composition. We present the results from 5 years of annual vegetation sampling which focused on short term non-woody vegetation response within the riparian channel at 3 restoration sites across southeastern Arizona. We examined the potential ways that RDS can preserve native species, encourage wetland species, and/or introduce nonnative species using a Control-Impact-Paired-Series study design. Species composition and frequency were measured within quadrats and zones on an annual basis. Multivariate bootstrap analyses were performed, including Bray-Curtis dissimilarity index and non-metric multidimensional scaling ordination. We found that response to RDS was variable and could be related to the level of degradation or proximity to groundwater. The non-degraded site did not show a response to RDS and the severely degraded site showed a slight increase in vegetation frequency, but the moderately degraded site experienced a significant increase. At the moderately degraded site, located between two historic ciénegas (desert wetlands), species composition shifted and nonnative species invaded, dominating the vegetation increase at this location. At the severely degraded site, pre-existing wetland species frequency increased in response to the installation of RDS. These findings extend the understanding of RDS effects on vegetation, provide scenarios to help land and water resource managers understand potential outcomes, and can assist in optimizing success for restoration projects. [ABSTRACT FROM AUTHOR]

Vegetation, water, and carbon dioxide have complex interactions on carbon mitigation in vegetation–water ecosystems. As one of the major global change drivers of carbon sequestration, flooding disturbance is a fundamental but poorly discussed topic to date. The aquatic and associated riparian systems are highly dynamic vegetation–water carbon capture systems driven by fluvial processes such as flooding. However, their global carbon offset potential is largely unknown. This study examines daily CO2 perturbations under flooding disturbance in the river (fluvial area) and associated riparian areas with 2 year in situ observations along the Lijiang. We find that, though the submerged riparian area behaved as a carbon source during the flooding season (CO2 flux: 2.790 gm-2d-1), the riparian area and the fluvial area as a whole transformed from a carbon source in pre-flooding season (1.833 gm-2d-1) to a carbon sink after recovery in post-flooding season (- 0.592 gm-2d-1). The fluvial area sequestered carbon (- 0.619 gm-2d-1) in post-flooding season instead of releasing carbon as in pre-flooding season (2.485 gm-2d-1). Also, the carbon sequestration capacity of the riparian area was enhanced in post-flooding season (pre-flooding season: - 0.156 gm-2d-1 , post-flooding season: - 0.500 gm-2d-1). We suggest that post-disturbance recovery of riparian vegetation played a vital role in this transformation, due to its stronger carbon uptake capacity after recovery from the flooding disturbances. The findings shed light on the quantitative modelling of the riparian carbon cycle under flooding disturbance and underlined the importance of the proper restoration of riparian systems to achieve global carbon offset. [ABSTRACT FROM AUTHOR]

Worldwide, riparian zones of many intermittent rivers and ephemeral streams (IRES) have been severely degraded. However, compared with perennially flowing waters, there have been few restoration efforts (e.g., revegetation, livestock removal) to halt or reverse this degradation. Even rarer are assessments of whether desired responses occurred and, if so, their underlying mechanisms, especially where flow extremes such as drying and flooding in IRES might alter or delay ecological responses to restoration.In order to assess how aquatic invertebrate communities responded to riparian replanting and livestock removal in three degraded lowland IRES in southeastern Australia, we conducted an eight‐year experiment (2004–2013), sampling paired control (unrestored) and treatment (restored, between 2005 and 2007 across creeks) sites twice yearly before and after restoration. To evaluate likely mechanisms underlying invertebrate responses to riparian restoration, we used a range of structural (e.g., richness) and functional (e.g., trait‐based) metrics. We also monitored environmental variables predicted to be likely drivers of aquatic invertebrate responses such as macrophyte and canopy cover, water quality, instream organic matter and instream wood. The study coincided with the last few years of a decade‐long drought that broke with severe floods (in 2010–2012), so we opportunistically examined how these hydrological extremes affected invertebrate responses to riparian restoration.At all three sites, macrophyte and canopy cover, water quality, organic matter and instream wood were comparable at treatment and control sites throughout the eight‐year experiment. There were also no significant differences in structural or functional metrics to indicate aquatic invertebrate responses to restoration after 6–8 years. This lack of predicted invertebrate responses apparently reflected how severely the drought impeded the riparian restoration, delaying even short‐term responses. Pervasive effects of catchment‐scale degradation may have further diminished the predicted benefits of the reach‐scale restoration efforts.By contrast, invertebrate metrics responded strongly to flow extremes, especially the brief floods that occurred as drought broke. These responses were evident for functional groups and individual families (especially rheophilic ones), but were not detected by a commonly used integrative measure of stream condition. This highlights the importance of selecting appropriate indicators in restoration monitoring programs and recognising their variability in responsiveness to restoration versus flow extremes.IRES are abundant and, in many parts of the world, increasingly common. Understanding how their inherent hydrological extremes may delay, modify and even overwhelm predicted responses to riparian restoration is crucial to setting realistic goals for IRES in the Anthropocene. Furthermore, assessing the success of riparian restoration in IRES requires a long‐term view given the extended time frames over which responses may occur, especially when expectations are often based on results of riparian restoration of perennial streams and rivers. [ABSTRACT FROM AUTHOR]

Stream temperatures have been increasing worldwide, in some cases reaching unsustainable levels for aquatic life. Riparian revegetation has been identified as a strategy for managing stream temperatures by blocking direct solar radiation. In this study, the effects of riparian vegetation on stream temperatures were included within the Soil & Water Assessment Tool (SWAT) model through a shade factor parameter. An equilibrium temperature approach was used to integrate the shade factor in an energy balance context. The stream temperature sub-model was improved using the new energy balance equation and integrated into SWAT. Unlike existing models, the modified SWAT model enables improved representation of two processes – mass and heat transfer – that influence stream temperature change and enables simulation of shading and its effects on stream temperatures at sub-basin scales. The updated SWAT model was tested in Dairy McKay Watershed, OR, USA, for four scenarios: current conditions of riparian vegetation, full restoration, efficient restoration, and no vegetation. The model calibration under current riparian vegetation showed good performance (Nash–Sutcliffe efficiency NSE > 0.74). Stream temperature reduction and number of days with stream temperatures above survival limits (NDSTASL) for aquatic species were also evaluated as measures of riparian shade performance. Findings showed average temperature reductions of 0.91 ∘ C (SD = 0.69 ∘ C) and reductions in NDSTASL of 17.1 d over a year for full riparian restoration and average reductions of 0.86 ∘ C (SD = 0.67 ∘ C) and 16.2 d for efficient restoration. Notwithstanding the similar benefits, efficient restoration was 14.4 % cheaper than full riparian vegetation restoration. [ABSTRACT FROM AUTHOR]

This study evaluated the survival of seedlings of native species of Cerrado - Brazil and its potential as an indicator of ecological restoration of riparian forests. The factors affecting survival were also analyzed. The experiment consisted of three planting models with three replications (T1 = nucleation: Anderson model; T2 = nucleation: Anderson model + artificial perches; T3 = filling line and diversity line). The influence of factors such as leaf herbivory, stem herbivory, absence of leaves (predation, dehydration or malnutrition) and sprouting/regrowth survival were assessed by cluster analysis. The survival rates ranged from 58.6 to 100% (average 73.6%). Out of eighteen species, fifteen showed survival rate above 60%, and could be potentially used in the restoration of degraded areas. The hierarchical clustering using survival efficiency and biotic factors resulted in the distinction of two groups of species with high frequency of leaves and stem herbivory, differing statistically (test "t", p < 0.05) in the sprouting and regrowth. The survival efficiency shows potential of being used as a restoration indicator. [ABSTRACT FROM AUTHOR]

Restoration has the potential to increase habitat heterogeneity through the creation of unique habitat patches that, in turn, increase regional species richness or gamma diversity. While biological diversity and habitat heterogeneity are important factors to consider under a shifting climate, restoration actions and outcomes rarely examine these components. In this study, we examined the effects of riparian beaver dam analog (BDA) restoration on aquatic invertebrate diversity and habitat heterogeneity. Although the effects of BDAs on hydrology, geomorphology, and salmonid habitat have been explored, we are unaware of any studies assessing their effects on aquatic invertebrate diversity and the food web that supports them. We sampled aquatic invertebrates, basal carbon resources, dissolved nutrients, turbidity, and water temperature in pre‐ and post‐BDA pond, side channel, and mainstem habitat over a three‐year period. The BDAs functioned similarly to natural beaver dams and created slow‐water environments that accumulated fine particulate organic material and increased pelagic phytoplankton production. Nonmetric multidimensional scaling, permutation multivariate analysis of variance, and Mantel's tests demonstrated that these changes led to the formation of a unique invertebrate community populated by lentic macroinvertebrates and zooplankton, which increased beta‐diversity and gamma diversity. Further, BDAs in our study maintained high densities of invertebrates and buffered water temperatures in comparison to adjacent lotic habitats. These results support our hypothesis that BDAs can enhance invertebrate beta and gamma diversity through the creation and colonization of unique pond habitat and improve habitat and resource heterogeneity for native fishes under variable climate conditions. [ABSTRACT FROM AUTHOR]

Agricultural pollution, especially phosphorus (P) can cause eutrophication of freshwater quality. Riparian buffers are best management practices (BMPs) which intercept agricultural pollution. However, they are frequently degraded by reduced biodiversity. P mitigation in riparian buffers can be enhanced through mycorrhizal inoculation and cyclical coppicing. We report on a myco‐phytoremediation project that investigates mycorrhizae's effect on vegetation's ability to lower legacy soil P, soil water P, and increase woody biomass P uptake. It also aimed to restore pollinator habitat through planting a diverse, native plant palette (32 species), blooming from February to November. Planting and offering culturally relevant plant materials to the Abenaki contributes to their land rematriation process. The study was located on unceded Abenaki territory at Shelburne Farms, within 300 m of Lake Pitawbagw (Lake Champlain) which is impacted increasingly by P pollution from colonial and conventional agricultural practices. Along a drainage way three treatment plots were installed: buckthorn vegetation (OIV) left in place as the control, and two restored diverse multi‐synusium plant communities, consisting of either uninoculated (RV) or inoculated with 19 mycorrhizal species (RVM). After 2 years, soil water soluble reactive P extracted from lysimeter samples was not affected by treatment but varied over time. However, water extractable SRP (WEP‐SRP) and TP (WEP‐TP) followed this trend RV > OIV > RVM which was inversely and linearly related to mycorrhizal density. Plants are best harvested in late summer when P concentrations are highest. Restoration science can flourish through reciprocally partnering with Original Peoples who hold expertise in ecological reconciliation. [ABSTRACT FROM AUTHOR]

Context: Germination is a vulnerable life stage for plants, therefore understanding the dynamics of seed ecology is essential to guiding management recommendations for highly invasive weeds. Aim: We addressed the knowledge gap for how seeds contribute to the invasion process for European blackberry (Rubus anglocandicans), a threatening weed across the riparian ecosystems of south-western Australia. Methods: We performed mechanical, chemical and thermal treatments on seeds to test for changes in germination success and conducted seed-burial trials to monitor seed viability over time in the soil seedbank. Key results: In germination trials, freshly picked and frugivore egested seeds failed to germinate with the endocarp intact. With the endocarp removed, germination remained lower at 4–6 months compared with 10–28 months after collection, indicating a significant after-ripening period. Seeds in intact endocarps survived water immersion for more than 2 months, indicating an ability to survive winter flooding. Acid immersion did not improve germination. The germination success of seeds with endocarp removed increased linearly above 11°C, was greatest at 30°C and thereafter declined rapidly (no survival at 40°C). In a 5-year seed-burial trial, germination varied from 7.6 to 48.4% and was significantly lower closer to a river, and in areas where 'blackberry decline' syndrome was present. Conclusions: While germination of seed without its pyrene coat occurred over a range of controlled conditions, the natural processes needed to break the pyrene remain unknown. Implications: High germination success and the long-term survival of seeds in soil clarifies that the management of blackberry remains a difficult challenge in Australia. Understanding seed germination is a critical element towards developing management strategies for invasive weeds, such as blackberry in south-western Australia. Seeds (pyrenes) of blackberry did not germinate under a range of conditions unless the outer coat of the pyrene, the endocarp, was removed. Pyrenes were buried in four treatments along a river bank, resulting in significant differences in survival. Trigger(s) for germination remain unknown, but long-term viability of the soil seedbank does not augment well for control. [ABSTRACT FROM AUTHOR]

Human activities and climate change have increased damage to riparian forest and their functions, stimulating interest in riparian restoration research and resulting in a surge of related publications. However, a comprehensive bibliometric analysis of riparian restoration research has been lacking until recently. To understand trends and hotspots in riparian restoration research, we performed a literature search of riparian restoration publications from 1990 to 2022 based on the Web of Science database. We found 2121 peer-reviewed articles, and then each paper was bibliometrically researched, analyzing authors, institutions, countries, citations, journals, publication years, and keywords. The results showed a growing number of annual articles during 1990–2022, but declining average citations. Environmental science, ecology, biodiversity conservation, engineering, and forestry were popular fields in riparian restoration. Publications on the riparian restoration field were widely dispersed in different journals, but Restoration Ecology and Ecological Engineering have higher influence and more publications and citations than other journals. Lorenz A. W., Nilsson C., and Kondolf G. M. were the most competitive authors because of their high number of publications and citations. The USA had the greatest research output and the most citations. American scientists preferred national collaboration, while Switzerland scientists engaged more in international collaborations. Research focus shifted from ecosystems and rivers before the 21st century to management topics after 2001 and biodiversity and conservation after 2011. This study provides valuable insights into the progress of riparian restoration research globally.

Riparian vegetation on river borders can affect the riparian ecosystem of the watershed related to its function as a buffer zone and ecotone between water and land. A high diversity of riparian vegetation can indicate that the ecosystem of a river border is in good condition. Therefore, it is helpful to inventory the diversity of vegetation in the riparian zone, which was done in this study using the Shannon-Wiener diversity index. In this research, four plots measuring 5m x 5m, spread across upstream, middle, and downstream areas were used to analyze the types of vegetation, including trees, shrubs, and herbs. The diversity index (H') results revealed four vegetation species at the tree level, twelve species at the shrub level, and six species at the herb level. The range of H' values in all sample plots was 1< H' <3, so the river border was shown to have moderate diversity, which indicated that the ecosystem in the Sampean watershed is relatively balanced. It is necessary to preserve the riparian buffer zone through riparian vegetation restoration management to improve the ecosystem balance of the Sampean watershed. [ABSTRACT FROM AUTHOR]

In recent years, numerous directives worldwide have addressed the conservation and restoration of riparian corridors, activities that rely on continuous vegetation mapping to understand its volumetric features and health status. Mapping riparian corridors requires not only fine‐scale resolution but also the coverage of relatively large areas. The use of Unmanned Aerial Vehicles (UAV) allows for meeting both conditions, although the cost‐effectiveness of their use is highly influenced by the type of sensor mounted on them. Few works have so far investigated the use of photogrammetric sensors for individual tree crown detection, despite being cheaper than the most common Light Detection and Ranging (LiDAR) ones. This work aims to improve the individual crown detection from UAV‐photogrammetric datasets in a twofold way. Firstly, the effectiveness of a new approach that has already achieved interesting results in LiDAR applications was tested for photogrammetric point clouds. The test was carried out by comparing the accuracy achieved by the new approach, which is based on the point density features of the analysed dataset, with those related to the more common local maxima and textural methods. The results indicated the potentiality of the density‐based method, which achieved accuracy values (0.76 F‐score) consistent with the traditional methods (0.49–0.80 F‐score range) but was less affected by under‐ and over‐fitting. Secondly, the potential improvement of working on intra‐annual multi‐temporal datasets was assessed by applying the density‐based approach to seven different scenarios, three of which were constituted by single‐epoch datasets and the remaining given by the joining of the others. The F‐score increased from 0.67 to 0.76 when passing from single‐ to multi‐epoch datasets, aligning with the accuracy achieved by the new method when applied to LiDAR data. The results demonstrate the potential of multi‐temporal acquisitions when performing individual crown detection from photogrammetric data. [ABSTRACT FROM AUTHOR]

Screwbean Mesquite (Stromocarpa pubescens), an ecologically and culturally important riparian tree in the North American desert southwest, has experienced a precipitous decline over the past two decades with several documented die-off events resulting in local extinctions. The decline has received little attention, however. To better understand causes of the die-offs, we surveyed 29 populations across the species' range for patterns of decline and found that 16 populations contained trees exhibiting identical disease symptoms (gummosis, cankers). Diseased populations were clustered in the western portion of the range where local extinction has occurred. The fungus Neoscytalidium dimidiatum was isolated and identified molecularly in 100 % of diseased tissue samples taken from 24 trees at six sites. Pathogenicity tests were performed by inoculating 10 naive trees with isolated N. dimidiatum. Inoculations produced identical disease symptoms and the fungus was reisolated from all infections. Branch canker symptoms were present at all but two sites experiencing active decline and sites with branch canker had experienced roughly 30 % more recent mortality than disease-free sites. More intensive monitoring of 244 trees at six sites throughout 2022 revealed that trees with branch canker symptoms showed more than four times new dieback (i.e. tissue death) through the growing season than non-diseased trees and ended the 2022 growing season with 29 % more dieback than non-diseased trees. Neoscytalidium dimidiatum is endemic to the region but this is the first documented example of widespread and aggressive infection by the species across the range of a native tree species. [ABSTRACT FROM AUTHOR]

We assessed the response of breeding birds to one decade of riparian restoration in the Colorado River delta including active vegetation management since 2010 and various environmental water deliveries since 2014. Bird surveys were conducted from 2002 to 2021 at 230 bird count stations distributed along five river reaches with different hydrogeomorphic characteristics, across 7 routes in actively revegetated ("restored") sites, and 20 routes in non-actively revegetated ("control") sites. Both restored and control sites could be affected by environmental flows/water deliveries. We examined the temporal trajectories of four community-aggregated metrics for 53 breeding species, and the number of detections (counts) for the 30 most frequently detected among the 53 species at the restored and control sites, using generalized linear mixed-effects models. Diversity and richness of the 53 breeding species were highest in the wettest river reach, but higher than in control sites in only one restored site within one of the driest river reaches. The avian community was recovering in control sites, ameliorating a long-term declining trend, perhaps indicating indirect positive effects of active restoration. The response to restoration of the 30 most common species was species-specific. Ten of the 16 riparian forest specialist species had more detections in restored sites of the wettest reach (vs. only two in the driest reach). Species with preference for agricultural fields and generalists had the highest counts along the entire delta. Generalists generally decreased following revegetation, which was another positive restoration effect. Our results will be used to help guide future restoration efforts. • Benefits of restoring degraded floodplains varied among species of breeding birds. • Response of riparian bird specialists to revegetation was positive but not universal. • Revegetation of floodplains reduced abundance of some generalist birds. • Effects of revegetation on breeding birds could go beyond its physical boundaries. • Response varied with different baseline conditions and characteristics of reaches. [ABSTRACT FROM AUTHOR]

Butterfly assemblages were studied from 2004 to 2007 at sites along the San Diego River. The purpose was to provide baseline information in the face of possible river improvement projects. We sampled in a protected area and in urban environments in hopes of identifying butterfly assemblages associated with a variety of riparian types. Multivariate analysis identified environmental variables significantly associated with butterfly assemblages such as riparian rank, soil moisture, air temperature, wind speed, nectar abundance, and forb & graminoid richness. There were significant correlations between butterfly species richness, butterfly abundance and a variety of environmental variables, including % shade. Sites located in the Mission Trails Regional Park contained unique butterfly species and were considered high value reference sites. Some butterflies of conservation interest were encountered such as: Panoquina errans Skinner, 1892 (Hesperiidae), Zerene eurydice Boisduval, 1855 (Pieridae), Tharsalea hermes W.H. Edwards, 1870 (Lycaenidae), and Apodemia virgulti Behr, 1865 (Riodinidae). A butterfly-centric metric was derived using species richness and significant variables identified via multivariate analysis to aid in management/monitoring of San Diego riparian sites. [ABSTRACT FROM AUTHOR]

The restoration of riparian habitats aims to provide habitat for birds and other environmental benefits; yet the evaluation of long-term outcomes is rare. To address this knowledge gap, we used bird and vegetation data from Coyote Creek Field Station (CCFS), in the southern San Francisco Bay Area, to assess the progress of two riparian revegetation projects (1987 Revegetation, 1993 Revegetation) over nearly two decades. Restoration success was measured by changes in 1) vegetation structure and composition, and 2) avian abundance, diversity, and community composition. We compared the two revegetated areas to a remnant riparian reference site and a managed floodplain overflow channel in three time periods (1996–1998, 2004–2006, 2012–2014) using ANOVA, Tukey's HSD tests, and beta diversity analysis of avian community composition. Over time, the restored areas became more similar to the remnant riparian reference site in four of seven indices. The avian community became more similar across the habitat areas over time, although differences remained. Migratory birds declined across all habitat areas, while resident and wintering birds declined in one revegetated habitat only. Overall we found that different types of data told different stories, indicating both convergence with the reference site and ongoing differences. Our findings highlight the need for multifaceted approaches to evaluating restoration success. [ABSTRACT FROM AUTHOR]

River temperatures are expected to increase this century harming species requiring cold‐water habitat unless restoration activities protect or improve habitat availability. Local shading by riparian vegetation can cool water temperatures, but uncertainty exists over the scaling of this local effect to larger spatial extents. We evaluate this issue using a regional spatial stream network temperature model with covariates representing shade effects to predict mean August stream temperatures across 78,195 km of tributaries flowing into the Columbia River in the northwestern United States. We evaluate nine scenarios predicting stream temperatures for three riparian shade conditions (current, restored, and no riparian vegetation) within three different climate periods (2000s, 2040s, and 2080s). Results suggest riparian shade restoration (2000s climate) could decrease mean August stream temperatures by 0.62°C across the study network. Under the same restored shade conditions, temperature predictions for tributaries at their confluence with the Columbia River range from 0.02 to 2.08°C cooler than under current shade conditions. The climate warming effect predicted for the 2040s and 2080s, however, is greater than the cooling effect from restoring riparian shade. Streams less than 10‐m bankfull width cooled more frequently with riparian shade restoration. In Oregon, the proportion of fish habitat for salmon and trout rearing and migration that meet temperature numeric water quality criteria could be increased by 20% under restored shade conditions although net habitat declines may still occur in the future. We conclude riparian vegetation restoration could partially mitigate future warming and help maintain cold‐water habitats that function as thermal refuges if implemented strategically. [ABSTRACT FROM AUTHOR]

Stream temperature appears to be increasing globally, but its rate remains poorly constrained due to a paucity of long-term data and difficulty in parsing effects of hydroclimate and landscape variability. Here, we address these issues using the physically based thermal model T-NET (Temperature-NETwork) coupled with the EROS semi-distributed hydrological model to reconstruct past daily stream temperature and streamflow at the scale of the entire Loire River basin in France (105 km 2 with 52 278 reaches). Stream temperature increased for almost all reaches in all seasons (mean =+0.38 ∘ C decade -1) over the 1963–2019 period. Increases were greatest in spring and summer, with a median increase of + 0.38 ∘ C (range =+0.11 to +0.76 ∘ C) and +0.44 ∘ C (+0.08 to +1.02 ∘ C) per decade, respectively. Rates of stream temperature increases were greater than for air temperature across seasons for the majority of reaches. Spring and summer increases were typically greatest in the southern part of the Loire basin (up to +1 ∘ C decade -1) and in the largest rivers (Strahler order ≥5). Importantly, air temperature and streamflow could exert a joint influence on stream temperature trends, where the greatest stream temperature increases were accompanied by similar trends in air temperature (up to +0.71 ∘ C decade -1) and the greatest decreases in streamflow (up to -16 % decade -1). Indeed, for the majority of reaches, positive stream temperature anomalies exhibited synchrony with positive anomalies in air temperature and negative anomalies in streamflow, highlighting the dual control exerted by these hydroclimatic drivers. Moreover, spring and summer stream temperature, air temperature, and streamflow time series exhibited common change points occurring in the late 1980s, suggesting a temporal coherence between changes in the hydroclimatic drivers and a rapid stream temperature response. Critically, riparian vegetation shading mitigated stream temperature increases by up to 0.16 ∘ C decade -1 in smaller streams (i.e. < 30 km from the source). Our results provide strong support for basin-wide increases in stream temperature due to joint effects of rising air temperature and reduced streamflow. We suggest that some of these climate change-induced effects can be mitigated through the restoration and maintenance of riparian forests. [ABSTRACT FROM AUTHOR]

Invasive species removal is a common focus in restoration ecology, but the ultimate goal of native plant species recovery and habitat recovery is often elusive. Control of invasive Tamarix spp. shrubs in the American Southwest has only sometimes led to increased native species cover; this is of particular concern for the protection of bird habitat, including the endangered Southwestern willow flycatcher (Empidonax extimus trailii, abbr. SWFL) that nests readily in Tamarix when native Salix canopy is absent. If we can identify the conditions that lead to more native trees as well as habitat protection for the SWFL, we can prioritize restoration efforts more effectively and reduce conflict between conservation goals. To determine whether reduction in the invasive Tamarix led to more Salix cover, we compiled data on vegetation, soils, and geographic conditions in 260 sites where Tamarix had been subject to control efforts and 132 positive and negative reference sites. We found that (1) reduction in Tamarix only increased Salix cover in wetter sites and was greater when a particular low-disturbance removal method was used; however, the increase did not typically compensate for the overall losses in canopy cover, and (2) Salix cover was generally highest in locations with low drought stress, as reflected by soil properties, distance to water, and climate. These results suggest that the presence and recovery of Salix is dependent on its relatively narrow environmental niche, in contrast with Tamarix's broader one. Thus, although abundance of Salix and Tamarix was negatively correlated, this is likely because of Salix's different niche, as much as or more than direct interspecific competition. Our findings demonstrate that removal of an invasive species does not necessarily lead to reestablishment of the native species they appeared to displace. We suggest that in the case of promoting habitat for SWFL and other birds, outcomes of restoration activity can be improved by focusing Tamarix removal efforts on sites more likely to promote Salix growth based on environmental characteristics. [ABSTRACT FROM AUTHOR]

Vegetation, water, and carbon dioxide have complex interactions on carbon mitigation in vegetation-water ecosystems. As one of the major global change drivers of carbon sequestration, water disturbance is a fundamental but poorly discussed topic to date. The riparian zone is a representative highly dynamic vegetation-water carbon capture system. Unfortunately, its global carbon offset functionality is remarkably underestimated. This study examines the daily CO2 perturbations in the riparian zone with two-year in-situ observations along the Lijiang River. We show that the riparian zone transformed from a carbon source to carbon sink after recovery from flooding. Consequently, a quantitative global riparian carbon offset model is proposed. Based on the intensity of flooding submergence and post-flooding vegetation coverage, ~0.11Gt·year-1 CO2 is captured following flooding, and 0.53 Gt·year-1 more CO2 is captured due to flooding, which is equivalent to 9.1 % of the global forest carbon sequestration. This finding shed new light on the quantitative modelling of the riparian carbon cycle under flooding disturbance, underlining the importance of the proper restoration of riparian systems to achieve global carbon offset. [ABSTRACT FROM AUTHOR]

Climate change is reducing summertime water availability and elevating water temperature, placing human consumptive needs in competition with needs of coldwater fishes. We worked with natural resource managers in the Snoqualmie River (Washington, USA) to develop riparian management scenarios, and used a process‐based modeling system to examine how a threatened population of Chinook salmon (Oncorhynchus tschawytscha) may respond to climate change and whether riparian restoration could reduce climate effects. Linking models of global climate, regional hydrology, water temperature, and fish, we projected that streams would become warmer year‐round and drier during summer, further stressing salmon. Climate change accelerated egg emergence, increased juvenile growth and survival, and accelerated outmigration of sub‐yearling migrants. Growth was depressed for salmon remaining instream during summer (potential yearling migrants). Riparian restoration counteracted ~10% of summer increases in water temperature, and affected salmon similarly regardless of whether riparian buffers were partially or fully restored, whereas riparian degradation further warmed streams. Riparian restoration fully mitigated climate change effects on potential yearling migrant size, but only minimally affected sub‐yearling migrants (assessment metrics changed <2%). Our results will be useful for watershed managers in aligning priorities for fish and humans and our framework can be applied elsewhere. Research Impact Statement: Coupling a hydroclimatic and a fish model enabled us to mechanistically evaluate when and where riparian restoration was most likely to benefit a threatened salmon population in a future climate. [ABSTRACT FROM AUTHOR]

The riparian vegetation of many rivers around the world is impacted by flow regulation for hydropower. Water levels behind dams are being raised to generate electric energy, forming river reservoirs. River regulation has a large impact on the riparian vegetation, which influences both the adjacent aquatic and terrestrial ecosystems. Therefore, the restoration of degraded riparian vegetation in river reservoirs has been of increasing research interest.Propagules dispersed from connected tributaries via water (hydrochory) are considered a vital source for the recovery of riparian vegetation in regulated rivers. However, the hydrochorous dispersal of plant propagules in river reservoirs is unclear. We explored the dispersal distance and deposition patterns of hydrochorous propagule mimics in three tributaries that are regulated by the Three Gorges Reservoir (TGR) in China.In eight out of nine release experiments, 95% of propagule mimics were found within 3 km downstream from the release points. Cumulative wind speed was the most important factor affecting the dispersal distance of propagule mimics in the TGR. However, the dispersal distance of propagule mimics was not significantly affected by water‐level variation and channel sinuosity. Variations in water level strongly affected the deposition pattern of propagule mimics, with only 6.6% of the propagule mimics stranding on the riparian zones under raised water level and 83.8% stranding under declined water levels. The majority of stranded propagule mimics were deposited at gentle slopes (0–20°).Synthesis and applications. Our results suggest that the majority of propagules that enter river reservoirs via water would be retained within the first few kilometres. Wind and water level variation are the main factors determining the dispersal distance and deposition pattern of propagules. Our findings have applications for riparian vegetation restoration in river reservoirs. The vegetation in steep riparian zones distant from free‐flowing tributaries should be the priority for restoration actions because these areas receive limited hydrochorous propagules. The plant biodiversity and hydrological connectivity of connected tributaries, which is an important propagule sources, should be protected. The seasonal dominant wind pattern should be considered when evaluating the importance of tributaries as the source of hydrochorous propagules for river reservoirs. [ABSTRACT FROM AUTHOR]

The plant dormancy period in the riparian zone affects the activity of microorganisms and their related nitrogen (N) process, which necessitates an investigation of the influence of the dormancy period on the microbial community. This study sampled two groups of soils (ashore and offshore soils) of two typical plants (Acorus calamus, Canna indica) in rhizosphere soils and bulk soils during the dormancy period to study the microbial communities. The results suggested that in ashore soils, especially in Canna indica soils, there was a lower abundance of N-related genes (4.79 × 106 copies/g) due to relatively competitive ecological niche competition because of possible sufficient substrate. Therefore, microbial communities still play a major role in the removal of N-related nutrients during plants' dormancy period. In addition, the results also showed that during the plant dormancy period, the cell necrosis processes accounted for relatively lower proportions (15.75%, 7.54%, 21.46%, and 5.23% in ashore and offshore Canna indica and ashore and offshore Acorus calamus, respectively), suggesting an unexpected fairly strong microbial survival ability in the dormancy period compared to the commonly expected weak microbial state. This high microbial vitality provides us insight into the restoration of riparian soils during the plant dormancy period. [ABSTRACT FROM AUTHOR]

The investment to restore riparian systems necessitates employing data‐driven planning, implementation, and management. To evaluate the demography/growth of riparian plants established vegetatively, we measured 3 years of survival and biometrics for five tree/shrub species experimentally planted as pole cuttings within a large restoration program in a Mediterranean‐climate riparian system. During the experiment, a recently introduced ambrosia beetle, Euwallacea whitfordiodendrus (polyphagous shot hole borer), colonized pole cuttings, providing an opportunity to evaluate beetle establishment rates among species. Pole cutting survival varied significantly among species and reflected their relative ability to propagate vegetatively. Baccharis salicifolia had over 90% survival, while Salix lasiolepis and S. laevigata had intermediate, and Populus trichocarpa and P. fremontii had low survival. Canopy growth reflected species life histories. The small tree/shrub, S. lasiolepis, had robust early growth, while slower growing, larger tree species (S. laevigata, P. trichocarpa, and P. fremontii) filled in canopy later. Only S. lasiolepis was colonized by E. whitfordiodendrus during the second year and had the greatest infestation rates in all years. All species except B. salicifolia were infested by the third year. Beetles tended to colonize larger trees. Our observed survival and growth trends can serve as a guide for estimating planting density and vegetation structural development over time, and to inform adaptive management of riparian species of Mediterranean‐climate and other arid‐land systems. Ecosystem stressors, such as invasive insects and their impacts to plant growth, must be considered during restoration as introductions are anticipated to continue with increased severity with climate change. [ABSTRACT FROM AUTHOR]

Ecological engineering construction is the main method for urban riparian landscape restoration. Continuous ecological environmental monitoring can reflect the effects of engineering construction and can provide a scientific basis for the improvement of engineering technology. However, the evaluation of riparian ecological engineering mainly focuses on the water environmental function and biodiversity conservation function after the construction period. Studies on the long-term evaluation of regional microclimate regulation and human settlement improvement are limited. In this paper, an ecological restoration project along the Yitong River in northern China was selected as the research object. Temperature, relative humidity and wind speed under different vegetation type combinations were monitored in the riparian ecological engineering construction during the first, second, third and tenth years. The temperature–humidity index (THI) was selected to evaluate human comfort and the improvement effect of microclimate was assessed for different vegetation type combinations. The results showed that vegetation type combinations can play a good role in regulating the microclimate and human comfort. The riparian ecological restoration project achieved a stable function for microclimate regulation in the third year. There was no significant regulation difference between tree–shrub–herb and tree–herb combinations. To realize the optimization of ecological benefits, economic benefits and social benefits, the tree–herb combination can be appropriately increased, and the tree–shrub–herb can be reduced in the application of ecological engineering. Microclimate regulation is an important achievement in engineering construction effects and can be regarded as one of the indices to evaluate the effect of ecological restoration. [ABSTRACT FROM AUTHOR]

Restoring riparian ecosystems in human-dominated landscapes requires attention to complexity, and consideration of diverse drivers, social actors, and contexts. Addressing a Global North bias, this case study uses a mixed-method approach, integrating historical data, remote sensing techniques and stakeholder perceptions to guide restoration of a river in the Western Cape, South Africa. An analysis of aerial photographs of the riparian zone from 1953 to 2016 revealed that although anthropogenic land conversion happened primarily before the 1950s, several land use and land cover classes showed marked increases in area, including: waterbodies (+ 1074%), urban areas (+ 316%), alien weeds (+ 311%) and terrestrial alien trees (+ 79%). These changes have likely been driven by land fragmentation, disturbance, and agricultural intensification. Stakeholder interviews revealed that despite the clear need for restoration, several barriers exist to successful implementation; these stem from inadequate financial resources, inappropriate funding models, institutional challenges, and a lack of techno-scientific knowledge. We give several recommendations to overcome these barriers. [ABSTRACT FROM AUTHOR]

Riparian zones are a vital interface between land and stream and are often the focus of stream restoration efforts to reduce nutrient pollution in waterways. Restoration of degraded stream channels often requires the removal of mature trees during major physical alteration of the riparian zone to reshape streambank topography. We assessed the impact of tree removal on riparian groundwater quality over space and time. Twenty-nine wells were installed across 5 sites in watersheds of the Washington D.C. and Baltimore, Maryland, USA metropolitan areas. Study sites encompassed a chronosequence of restoration ages (5, 10 and 20 years) as well as unrestored comparisons. Groundwater wells were installed as transects of 3 perpendicular to the stream channel to estimate nutrient uptake along groundwater flow paths. Groundwater samples collected over a 2-year period (2018-2019) were analyzed for concentrations of dissolved inorganic carbon (DIC), dissolved organic carbon (DOC), total dissolved nitrogen (TDN), and dissolved components of calcium (Ca), potassium (K), magnesium (Mg), sodium (Na), sulfur (S) and other elements. Results showed some interesting patterns such as: (1) elevated concentrations of some nutrients and carbon in riparian groundwater of recently restored (5 year) sites; (2) decreasing linear trends in concentrations of TDN, K and S in groundwater during a 2 year shift from wet to dry conditions; (3) linear relationships between DOC (organic matter) and plant nutrients in groundwater suggesting the importance of plant uptake and biomass as sources and sinks of nutrients; (4) increasing concentrations in groundwater along hydrologic flow paths from uplands to streams in riparian zones where trees were recently cut, and opposite patterns where trees were not cut. Riparian zones appeared to act as sources or sinks of bioreactive elements based on tree removal. Mean TDN, DOC, and S, concentrations decreased by 78.6%, 12.3%, and 19.3% respectively through uncut riparian zones, but increased by 516.9%, 199.7%, and 34.5% respectively through the 5-year cut transects. Ecosystem recovery and an improvement in groundwater quality appeared to be achieved by 10-20 years after restoration. A better understanding of the effects of riparian tree removal on groundwater quality can inform strategies for minimizing unintended effects of stream restoration on groundwater chemistry. [ABSTRACT FROM AUTHOR]

Recent human population growth in North America's southern Appalachian Mountains has raised concerns about the effects of ex-urban development on its streams and their at-risk biota. The few studies to examine effects of land-use change in this region found that many headwater species require well-forested watersheds. Alasmidonta raveneliana is endemic to montane streams in North Carolina and Tennessee and during the past 20 years populations have declined alarmingly in several former strongholds. In 2015, we conducted surveys for A. raveneliana and quantified in-stream habitat and land-use at 25 current or historically occupied sites in the Nolichucky Drainage. We found that A. raveneliana populations were only detected at sites with well-forested watersheds and low proportions of fine substrates. Thin-sections revealed that A. raveneliana is fast-growing and short-lived (max age ~ 12 years) which may be an adaptation to unpredictable headwater streams. However, like many headwater specialists, A. raveneliana appears sensitive to changes in forest cover. Our results suggest that subtle changes in stream habitats linked to land-use change are a significant threat to the long-term survival of this species. Protection of forested headwaters and restoration of riparian zones appear to be the best strategies for conserving populations of this critically endangered freshwater mussel. [ABSTRACT FROM AUTHOR]