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Sesbania virgata is a pioneer shrub from the Fabaceae family, native to riparian environments in northeast of Argentina, southern of Brazil and Uruguay. In peri-urban riparian soils, metal contamination is a frequent problem, being its bioavailability partly determined by the stabilization time and frequency of contamination events. The effect of time elapsed between chromium (Cr) soil enrichment and plant seeding and Cr doses on S. virgata tolerance and metal absorption were evaluated. Treatments were developed by adding Cr (80–400 ppm) to the soil and allowing two days or fifteen months to elapse before sowing, and a control treatment without Cr addition. After 150 days from seeding, bioaccumulation and translocation factors, growth parameters (dry biomass and its aerial/radical allocation pattern, stem length and its elongation rate), morphological parameters (root volume and leaf area), and physiological parameters (chlorophyll content) of the specimens were determined. The emergence of S. virgata was inhibited since 150 ppm when Cr was added to the soil two days before seeding, with Cr accumulation in roots starting at 80 ppm (17.4 ± 2.5 mg kg−1). Under 15 months of metal stabilization, S. virgata plants survived across the entire range of Cr doses tested, with accumulation in roots since 100 ppm (35.5 ± 0.2 mg kg−1) and metal translocation to aerial tissues only under 400 ppm. The results obtained showed that S. virgata did not have high BCF and TF values, suggesting that it cannot be classified as bioaccumulator of Cr under the tested conditions. However, its presence in environments contaminated with Cr can be beneficial, as it helps to stabilize the metal in the soil. [Display omitted] • Chromium stabilization time affects S. virgata 's tolerance and metal absorption. • S. virgata phytostabilizes Cr up to 400 ppm when added to soil long before sowing. • The Cr bioconcentration factor does not increase with increasing doses of metal. • Cr translocation only takes place at the highest Cr dose tested (400 ppm). • S. virgata is not a Cr bioaccumulator species (BCF and TF less than 1). [ABSTRACT FROM AUTHOR]

Conversion of forest to oil palm agriculture is a significant and ongoing threat to tropical biodiversity. Despite this, little is known about the value of riparian reserves in oil palm and how these conservation set‐asides might best be managed to maintain biodiversity.We characterized bird communities of 28 sites in an oil palm‐forest mosaic in Sabah, Malaysia using 6,104 encounters from 840 point counts. Sites included oil palm riparian reserves of various vegetation quality and reserve widths, which were compared to oil palm streams without a riparian reserve as well as riparian and nonriparian control areas in continuous logged forest.Riparian reserves, oil palm waterways, and control sites in riparian and nonriparian forest supported distinct avifaunal communities. Riparian reserve width, forest quality, and amount of forest cover were the strongest predictors of bird species richness. For forest‐dependent species, each of these predictors had a stronger effect size when compared with all species. On average, reserves held 31% of all species and 30% of forest specialists, whereas riparian forest controls averaged 32% of all species, but 38% of forest species.Riparian reserves with >40 m of natural vegetation on each bank supported similar bird diversity to riparian forest control habitats found in continuous forest. However, to support equivalent numbers of forest‐dependent species and species of conservation concern, reserves would need to be at least 100‐m wide on each bank. The largest numbers of species were found in riparian reserves with above‐ground carbon densities exceeding 75 tC/ha, highlighting the importance of forest quality, as well as width, in supporting riparian bird communities.Synthesis and applications. If designed and protected appropriately, riparian reserves in oil palm estates support diverse bird communities, including many species of conservation concern. This can be achieved by designating large reserves (80–200 m total width). But, to maximize species numbers, forest disturbance should also be minimized prior to conversion as well as during plantation operations. If designed and protected appropriately, riparian reserves in oil palm estates support diverse bird communities, including many species of conservation concern. This can be achieved by designating large reserves (80–200 m total width). But, to maximize species numbers, forest disturbance should also be minimized prior to conversion as well as during plantation operations. [ABSTRACT FROM AUTHOR]

In West Tripura district, river bank erosion becomes very common during monsoons along the Haora River and the Sonai Gang. Erosion occurs across 45.39 km (96% of the total length) of the Haora River and 20.12 km (90% of the total length) along the Sonai Gang. The main cause of river bank erosion in the district is the nature of bank material with respect to its erodibility factor (resisting force). The objectives of this study were to identify the nature of bank material of the rivers in West Tripura district and to analyse the shear strength of these materials. Samples were collected from twelve sites at various depths from top of the river bank up to the water level. Hydrometer test and grain size were also analysed. Uniformity coefficient (Cu) and coefficient of curvature (Cc) were calculated to identify the shear strength of bank soil. Tests revealed that the bank soils contain more than 90% sand and less percentage of silt and clay. This makes the soil non-cohesive and leads to maximum erosion. [ABSTRACT FROM AUTHOR]

Human impact, particularly land cover changes (e.g., agriculture, construction) increase erosion and sediment loading into streams. Benthic species are negatively affected by silt deposition that coats and embeds stream substrate. Given that riparian buffers are effective sediment filters, riparian restoration is increasingly implemented by conservation groups to protect stream habitats. Limited funding and a multitude of impaired streams warrant the need for cost-effective prioritization of potential restoration actions. We created a decision-support framework for conservation agencies and aquatic resource managers to prioritize riparian restoration efforts. Our framework integrates GIS data and field surveys into a statistical model to predict instream silt from estimates of upland soil loss and riparian filtration capacity. We focus specifically on prioritizing sites in upper sections of the Roanoke and Nottoway river basins (Virginia, US) based on observed records of Roanoke logperch (Percina rex), an imperiled sediment-sensitive species. Our statistical approach examines soil characteristics, land cover, precipitation, topography, and annual soil loss estimates from the empirically derived Revised Universal Soil Loss Equation, combined with land cover-based riparian filtration capacity as potential stream habitat predictors. We found riparian filtration capacity to be a significant predictor of silt cover, while precipitation was a significant predictor of embeddedness. Spatial scale was also a factor, in that spatial variance in silt cover and embeddedness was more accurately predicted at smaller spatial extents. Ultimately, our model can be used as a prioritization tool for mitigating high siltation areas, or for protecting low soil erosion areas. [ABSTRACT FROM AUTHOR]

Riparian reforestation is a common restoration action in urban streams, but relatively little is known about the influence of local riparian vegetation in the face of watershed-scale urban land cover. Allochthonous organic matter and benthic algae are important basal energy resources in streams, but the roles of watershed urbanization vs near-stream vegetation in the availability of these resources are not well understood. Our goal was to understand how the interaction of land cover at 2 spatial scales (watershed vs reach) and seasonal dynamics shape basal resources and their effects on macroinvertebrate communities. We assessed relationships between seasonal patterns in standing stocks of particulate organic matter (POM) and benthic periphyton and macroinvertebrate community composition in open- and closed-canopy reaches of 4 urban and 4 reference streams in northern Kentucky, USA. POM standing stocks were not strongly influenced by watershed or riparian condition. Benthic algal biomass was greater in urban than in reference streams in all seasons and in open than in closed riparian canopies in summer when light levels are most affected by a deciduous canopy. Relationships between macroinvertebrate functional feeding group (FFG) biomass and their primary food resources were influenced by watershed land use and season, but riparian canopy effects were minor. The proportion of collectors varied by season, whereas the proportion of shredders was higher in reference than urban streams. Scraper biomass was influenced by benthic algal biomass and varied seasonally, whereas predator biomass was driven by prey-insect biomass. Periphyton density was affected by the interaction of watershed- and reach-scale land cover and was the only basal resource strongly related to consumer taxa. Watershed land use influences the stream ecosystem, but local riparian canopy may be important in limiting benthic algal accumulation. [ABSTRACT FROM AUTHOR]

Abstract Restoring riparian shade to formerly forested streams in cleared land is an important step in the restoration of stream ecological health. In a companion paper, we validated a numerical model for diffuse non-interceptance (difn) against measurements made in precisely-constructed physical models for two simplified geometries ‘canyon’ and ‘cylinder’ with trees lacking canopy ‘shape’. In this paper, we extend the model to include canopy ‘shape’ by representing trees as ellipses or kites, and quantifying shading from canopy overhang of the channel. The ratio of tree height (h) to stream width (w) strongly influences stream shade and is a key parameter when scoping riparian revegetation. Canopy width, overhang and viewpoint affect stream shade and could profitably be included in water temperature and aquatic plant growth models. Tree shape has a second-order effect on shade, most noticeably near the stream banks. The model predicts shade assuming a sky of uniform radiance (viz., it predicts shade to diffuse radiation) on the premise that difn is a useful index of long-term averaged light exposure. The model successfully reproduced the trajectory of shade reductions following riparian restoration predicted using a published physically-based model, confirming its suitability for scoping riparian shade restoration. While it would be feasible to include direct radiation in the model, this would require additional input data and computational effort. [ABSTRACT FROM AUTHOR]

With drainage from the Waterton‐Glacier International Peace Park, the Waterton River was dammed in 1964 to trap spring flow and permit offstream diversion for irrigation. Field observations in the 1980s indicated some decrepit riparian woodlands suggesting drought stress of the black and narrowleaf cottonwoods (Populus trichocarpa, P. angustifolia) due to insufficient in‐stream flows. Subsequently, an environmental flow regime commenced in 1991 and provided “functional flows,” deliberately regulating in‐stream flow components intended to restore ecological processes and particularly (1) an increase of the minimum flow from 0.93 to 2.27 m3/s (mean discharge 21.9 m3/s) and (2) flow ramping, gradual recession after the spring peak. This study investigated the historic flow patterns and the growth, population age structure, and spatial distributions of riparian cottonwoods along the free‐flowing upstream and regulated downstream reaches over four dam operations intervals: the free‐flowing pre‐dam condition; the initial dammed interval to the mid‐1970s; a post‐dam and drought interval in the 1980s; and with the environmental flow regime. Analyses of sapling, shrub‐, and tree‐sized cottonwoods included tree ring analyses to determine ages and growth patterns, and distributions were assessed relative to streamside elevations and sediment textures. These indicated that there has been progressive cottonwood colonization after damming but the colonization band dropped in elevation with the reduced flow regime and the future woodlands could become narrower. The tree ring analyses indicated that the growth of established trees benefited from the functional flows and the increase in minimum flow was probably particularly beneficial to the riparian cottonwoods. [ABSTRACT FROM AUTHOR]

Environmental stressors associated with human land and water-use activities have degraded many riparian ecosystems across the western United States. These stressors include (i) the widespread expansion of invasive plant species that displace native vegetation and exacerbate streamflow and sediment regime alteration; (ii) agricultural and urban development in valley bottoms that decouple streams and rivers from their floodplains and reduce instream wood recruitment and retention; and (iii) flow modification that reduces water quantity and quality, degrading aquatic habitats. Here we apply a novel drainage network model to assess the impacts of multiple stressors on reach-scale riparian condition across two large U.S. regions. In this application, we performed a riparian condition assessment evaluating three dominant stressors: (1) riparian vegetation departure from historical condition; (2) land-use intensity within valley bottoms; and (3) floodplain fragmentation caused by infrastructure within valley bottoms, combining these stressors in a fuzzy inference system. We used freely available, geospatial data to estimate reach-scale (500 m) riparian condition for 52,800 km of perennial streams and rivers, 25,600 km in Utah, and 27,200 km in 12 watersheds of the interior Columbia River Basin (CRB). Model outputs showed that riparian condition has been at least moderately impaired across ≈70% of the streams and rivers in Utah and ≈49% in the CRB. We found 84% agreement (Cohen’s ĸ = 0.79) between modeled reaches and field plots, indicating that modeled riparian condition reasonably approximates on-the-ground conditions. Our approach to assessing riparian condition can be used to prioritize watershed-scale floodplain conservation and restoration by providing network-scale data on the extent and severity of riparian degradation. The approach that we applied here is flexible and can be expanded to run with additional riparian stressor data and/or finer resolution input data. [ABSTRACT FROM AUTHOR]

Difficult environmental policy issues often elicit fervent declarations to "follow the science." Such declarations ignore the essential role of values in policy making. The main purpose of this article is to clarify the relationships among science, values, and law in environmental policy. An important policy issue in wildlife conservation, is determining "how much is enough?" That is, what is the smallest amount of habitat or minimum population size that is adequate for the long-term survival of wildlife populations? This paper presents three case studies in which policy makers decided how much was enough for protecting freshwater salmonid habitats. The case studies are the federal Northwest Forest Plan, the Habitat Conservation Plan (HCP) for Washington's forested trust lands, and the HCP for Washington's forest practices rules. Because all three plans were developed for the same habitats and species in the same region over a span of roughly seven years, all drew from the same body of science. Hence, the differences among the conservation plans cannot be attributed to differences in the available science. We explain how differences in habitat conservation were largely due to differences in societal values that were expressed through different legal frameworks. The legal frameworks established unique policy decision spaces for each plan. Strong leadership, vague or ambiguous statutory language, and commitments to adaptive management expanded the decision space for policy makers. Our case studies also show how values affected each plan through negotiations amongst stakeholders and/or leadership by key political figures. By appropriately integrating. [ABSTRACT FROM AUTHOR]

Riparian habitats in the western United States are imperiled, yet they support the highest bird diversity in arid regions, making them a conservation priority. Riparian restoration efforts can be enhanced by information on species response to variation in habitat features. We examined the habitat selection of four riparian birds known as management indicators at restoration and reference sites along the Trinity River, California. We compared vegetation structure and composition at nest sites, territories, and random points to quantify used versus available habitat from 2012 to 2015. Vegetation in focal species' territories differed between site types, and from available habitat, indicating nonrandom site choice. Birds selected aspects of more structurally complex habitats, such as greater canopy cover, canopy height, and tree species richness. Yellow‐breasted Chats preferred greater shrub cover, and Yellow Warblers preferred greater cover by non‐native Himalayan blackberry. Territory preferences on restoration sites were often a subset of those on reference sites. One exception was canopy height, which was taller on restoration site territories than random points for all species, suggesting that birds preferentially used patches of remnant habitat. Few variables were significant in nest site selection. Restoration plantings along the Trinity River were only 3–10 years old during this study, and have not developed many of the characteristics of mature riparian habitat preferred by birds, but may improve in habitat value over time. Understanding habitat selection is especially important in recently human‐modified environments, where indirect cues used to assess habitat quality may become disassociated from actual habitat quality, potentially creating ecological traps. [ABSTRACT FROM AUTHOR]

Riparian willows provide important ecosystem functions, however, in some locations they have been degraded due to over-browsing by wild and domestic ungulates. Fires can also have a detrimental effect on riparian vegetation, but have positive effects by creating bare soil necessary for willow seed germination. Both active and passive methods of restoration are common, but questions related to willow seed production are not well studied. We examined two questions: 1) Are bare soil patches created by wildfire suitable for willow seedling establishment? and 2) How has aerial seed rain changed since the establishment of exclosures to limit access of ungulates to willow stands? Working in montane riparian areas in Rocky Mountain National Park (USA), we seeded 1 m2 plots on bare soil patches created by a wildfire and monitored germination and survival. Seeds germinated in 46% of the plots and the number of seedlings ranged from 1 to 591. Plots with higher average growing season soil moisture had greater numbers of seedlings and seedling survival rates. In a nearby unburned valley, we assessed aerial seed rain biweekly using traps established at the same locations as a previous study in 2000. Five years after the establishment of exclosures, aerial seed rain was lower than in the pre-fence year 2000. We conclude that fire could trigger willow seeding establishment and controlled burns used as a viable option for restoration. In addition, five years of fencing is insufficient to reestablish willow seed rain after a period of heavy browsing. [ABSTRACT FROM AUTHOR]

Abstract: Freshwater ecosystems and their associated biota are under increasing threats from multiple stressors including climate and land‐use change. The conservation of these ecosystems must be based on an integration of data including species physiological tolerances, the biotic and abiotic drivers of the distribution of populations, and demographic processes, to provide the comprehensive ecological information necessary for management. This study used a Bayesian belief network (BBN) to synthesize research on northern river blackfish, a threatened species in the upper Condamine River, Australia, into a probabilistic framework capable of predicting the complex relationships that exist between environmental conditions and population success. This study tested how predicted air temperature scenarios for the years 2050 and 2080, and catchment restoration scenarios, would be expected to affect three indices of population success: adult abundance, juvenile abundance, and juvenile recruitment. Compared with current climatic conditions, climate warming scenarios reduced the probability of future population success by between 0.4% and 1.6%. These shifts were almost completely offset, and even improved, when riparian zones were restored at the catchment scale, where changes ranged from an overall decrease of 0.2% to an increase of 1%. To achieve the highest probability of population success, the impacts of warming stream temperatures and the degradation of riparian zones must be mitigated. However, the model showed that there is still a possibility of complete population failure under a wide range of conditions, even when conditions appear to be suitable. To maximize the future population success of river blackfish we recommend targeting the restoration of hydrologically active catchment areas where grazing strongly influences stream biota. The use of a BBN allowed the combination of multiple sources of information to solve complex ecological problems, including how multiple stressors may affect threatened freshwater species. [ABSTRACT FROM AUTHOR]

The Blanco River, which flows through the limestone Balcones Canyonlands of central Texas (USA), experienced catastrophic flooding in May 2015 that resulted in significant biogeomorphic disturbance to its riparian corridor. High-resolution aerial and satellite imagery from pre- and post-flooding for a 55-km reach of river were used to map and categorize patterns of disturbance by degree of severity ranging from complete floodplain stripping to no disturbance. The most severe disturbance occurred within the floodway near the channel and decreased with lateral distance into the 100- and 500-year floodplains. Disturbance patterns previously identified in the literature including meander scour, parallel chute scour, convex bank erosion, and macroturbulent scour were all present following this event, as well as substantial disturbance proximal to tributary confluences. In the aftermath of this event, TreeFolks, a local nonprofit organization, engaged with the community to actively replant and restore the riparian corridor of the Blanco River on public and private lands. These reforestation efforts supplement the natural passive recovery of the riparian corridor, enabling the system to recover more quickly and be resilient to future flood events. [ABSTRACT FROM AUTHOR]

Rivers and riparian ecosystems have historically provided a range of beneficial goods and services to human societies. However, floodplains have also posed risks to the humans that came to rely upon them. Although riparian areas are among the most resource-rich and biodiverse ecosystems, they are also some of the most disturbed by human activity. Today, social and economic needs for water diverted off-stream are often pitted against the flow of water needed to maintain crucial instream ecological functions. The construction of dams has been a widely implemented method to control rivers for human purposes, particularly in the western United States. However, there is a growing movement to decommission dams, as stakeholders begin to recognize the ultimate value of restoring ecosystem services, including cultural ecosystem services; indeed, their restoration may be necessary to ensure lasting systemic resilience. Broader questions of dam decommissioning in the United States are receiving increasing attention by scholars and practitioners alike. In this paper, we adapt and apply seminal concepts from the adaptive cycle framework and cultural ecosystem services, particularly for Native Nations, and thereby assess the unfolding case of decommissioning and restoration on the Elwha River in northwest Washington State. The empirical evidence indicates that dam removal coincided with scalar and temporal alignment of multiple adaptive cycles and contributed to both short and long-term resilience. Further, the Elwha case represents an extremely important precedent in the evolution of river management practices, in which stakeholder-based collaborative governance incorporated knowledge coproduction and regulatory maneuvering to successfully overcome obstacles inherent in both dam decommissioning and subsequent restoration. We conclude by reflecting on lessons of broader relevance beyond the specific case of the Elwha. [ABSTRACT FROM AUTHOR]

Hydromorphological restructuring of river sections, i.e. river restoration measures, often has little effects on aquatic biota, even in case of strong habitat alterations. It is often supposed that the biotic response is simply delayed as species require additional time to recolonize the newly generated habitats and to establish populations. To identify and specify the supposed lag time between restoration and biotic response, we investigated 19 restored river reaches twice in a five-year interval. The sites were restored one to ten years prior to the first sampling. We sampled three aquatic (fish, benthic invertebrates, macrophytes) and two riparian organism groups (ground beetles and riparian vegetation) and analyzed changes in assemblage composition and biotic metrics. With the exception of ground beetle assemblages, we observed no significant changes in richness and abundance metrics or metrics used for biological assessment. However, indicator taxa for near-natural habitat conditions in the riparian zone (indicators for regular inundation in plants and river bank specialists in beetles) improved significantly in the five-year interval. Contrary to general expectations in river restoration planning, we neither observed a distinct succession of aquatic communities nor a general trend towards “good ecological status” over time. Furthermore, multiple linear regression models revealed that neither the time since restoration nor the morphological status had a significant effect on the biological metrics and the assessment results. Thus, the stability of aquatic assemblages is strong, slowing down restoration effects in the aquatic zone, while riparian assemblages improve more rapidly. When defining restoration targets, the different timelines for ecological recovery after restoration should be taken into account. Furthermore, restoration measures should not solely focus on local habitat conditions but also target stressors acting on larger spatial scales and take other measures (e.g. species reintroduction) into consideration. [ABSTRACT FROM AUTHOR]

Removal of invasive species is often an important, if not central, component of many riparian restoration projects, however little is known about the response of plant communities following this practice. In particular, active control of the exotic, dominant tree Tamarix spp is often a focus of riparian restoration, much of which occurring against a backdrop of biological control by a folivore beetle. Our research employed controls in both time and space to investigate the impact of active Tamarix removal methods in sites subjected to biological control in 40 sites sampled three times over a period of five years. We found that reduction in Tamarix cover was much greater over time with active means of removal, however the native understory increased both with and without active removal. Importantly, change in the relative cover of understory native species was significantly negatively correlated with change in Tamarix cover, with those sites that received a combination of low-disturbance-mechanical, chemical and bio-control showing greater increases in native understory dominance than those sites with biological control alone or high-disturbance mechanical control. Sites with only bio­control still contained 10% live Tamarix cover >7 yr since the beetle was released there. Taken together, these results suggest that the reduction of this exotic tree, even by biological control that leaves some canopy intact, can facilitate recovery of the native plant community. As such, this study supports the Field of Dreams hypothesis that states that once niches are restored, native plants should be able to recolonize. [ABSTRACT FROM AUTHOR]

Efforts are underway in many areas to restore riparian zones to arrest and/or reverse their degradation and the subsequent loss of the ecosystem services they provide. Despite strong links between edaphic conditions and riparian zone function, limited research has tested how soil properties respond to restoration, especially in an experimental context. With this important knowledge gap in mind, we established a field experiment to asssess structural vegetation and soil responses in the eight years following livestock exclusion and replanting in lowland streams in south-eastern Australia. On three streams, paired restored and control sites were experimentally established and we monitored vegetation (stem density, cover of bare ground and tree canopy, and loadings of organic matter), once beforehand, and then biennually after restoration. Selected soil properties (total carbon, total nitrogen, plant-available phosphorus) were sampled once shortly after restoration, then after another five years. Significant changes in structural vegetation occurred (e.g. decreased bare ground, increased plant stem density, organic matter, and canopy cover). In contrast, those soil properties did not respond. A mega-drought occurred throughout much of the study which was immediately followed by severe flooding. The floods redistributed organic matter at our study sites, with this effect mediated by vegetation structure: the probability of organic matter retention was positively correlated with groundcover and stem density of plants. The timing of flooding was also correlated with increased soil carbon and nitrogen, which could be due to increased productivity in these systems (for the former), or potentially due to increased fertiliser inputs or increased fixation (for the latter). Our study is the first to comprehensively and experimentally test how vegetation, litter layer and surface soil properties respond following riparian restoration, and will help guide the development and implementation of other monitoring programmes. [ABSTRACT FROM AUTHOR]

Abstract: Conservation projects increasingly aim to deliver both environmental and social benefits. To monitor the success of these projects, it is important to pick indicators for which there is a reasonable expectation of change as a result of the project, and which resonate with project stakeholders. Results chains are widely used in conservation to describe the hypothesized pathways of causal linkages between conservation interventions and desired outcomes. We illustrate how, with limited additional information, results chains can be turned into fuzzy models of social‐ecological systems, and how these models can be used to explore the predicted social and environmental impacts of conservation actions. These predictions can then be compared with the interests of stakeholders in order to identify good indicators of project success. We illustrate this approach by using it to select indicators for a water fund, an increasingly popular and multiobjective conservation strategy. [ABSTRACT FROM AUTHOR]

Coupled two-dimensional (2D) morphodynamic and bank erosion models are gaining attentions in recent years. It has been shown that such models have advantages over the one-dimensional (1D) modeling approaches. In this paper, a previous 2D bank erosion model with the moving mesh method is extended to include the fixed mesh approach. Further, two practical streams with differing complexity are simulated to demonstrate the extended model. Both the moving mesh and fixed mesh methods are used in the modeling. The model consists of two components: a 2D flow and mobile-bed model for vertical bed changes and hydraulic forces acting on a bank and a lateral bank retreat model. The 2D vertical model and the lateral bank erosion model are coupled together spatially and temporally through a special procedure and a common mesh. With the experiences gained with practical stream modeling, the modeling procedure and key model input parameters are described. The study shows that the moving and fixed mesh methods together make the extended bank erosion model numerically robust and capable of predicting both the vertical bed changes and the lateral stream bank erosion for complex streams. Each individual method, however, has its own limitations in terms of model accuracy and efficiency. The moving mesh works well if bank retreat is relatively small, e.g., less than one channel width, and produces more accurate results than the fixed mesh method. The fixed mesh may be needed for ensuring numerical stability if a bank may be subject to significant retreat (e.g., more than one channel width). The fixed mesh method, however, is less accurate than the moving mesh method and a much refined mesh may be needed. Both methods need future research and improvements in terms of their model accuracy. [ABSTRACT FROM AUTHOR]

Excessive sediment is a major pollutant to surface waters worldwide. In some watersheds, streambanks are a significant source of this sediment, leading to the expenditure of billions of dollars in stabilization projects. Although costly streambank stabilization projects have been implemented worldwide, long-term monitoring to quantify their success is lacking. There is a critical need to document the long-term success of streambank restoration projects. The objectives of this research were to (1) quantify streambank retreat before and after the stabilization of 18 streambanks on the Cedar River in North Central Nebraska, USA; (2) assess the impact of a large flood event; and (3) determine the most cost-efficient stabilization practice. The stabilized streambanks included jetties (10), rock-toe protection (1), slope reduction/gravel bank (1), a retaining wall (1), rock vanes (2), and tree revetments (3). Streambank retreat and accumulation were quantified using aerial images from 1993 to 2016. Though streambank retreat has been significant throughout the study period, a breached dam in 2010 caused major flooding and streambank erosion on the Cedar River. This large-scale flood enabled us to quantify the effect of one extreme event and evaluate the effectiveness of the stabilized streambanks. With a 70% success rate, jetties were the most cost-efficient practice and yielded the most deposition. If minimal risk is unacceptable, a more costly yet immobile practice such as a gravel bank or retaining wall is recommended. [ABSTRACT FROM AUTHOR]

Riparian forests are fundamental for water and soil protection and favor the creation of gene flow corridors between forest remnants. The restoration of riparian forests by seedling planting can usually accelerate the succession process, but these ecosystems are seldom evaluated in post-mined areas in the Amazon. In this context, the objective of this study was to evaluate the restoration trajectory of riparian forests after tin mining, using composition and structure indicators along with the selectin of the most suitable species for planting according to height and DBH increments. A total of eight riparian forests of different planting ages (2014, 2015, 2016, 2017, and 2021/2022) were evaluated, being currently 8.5 (RF_8.5), 7.5 (RF_7.5), 6.5 (RF_6.5), 5.5 (RF_5.5) and ≤ 1.5 (RF_1.5) years old. Permanent plots of 30 m × 30 m were allocated in each forest, with the number of units varying according to the total area size, with a minimum of 3 plots allocated. Our results show a gradual increase in the density of individuals and species over the three evaluations performed, emphasizing RF_6.5 and RF_1.5 areas. Using the NMDS analysis, the RF_8.5 and RF_1.5 did not present any floristic-structural similarities. The 10 species with the highest IVI represented more than 60% of the total in all the restored ecosystems. V. guianenses presented the highest relative density for all ecosystems under restoration, except for RF_1.5, which S. alata was highlighted. P. pendula was the most suitable for planting in all assessed riparian forests when mortality and height and diameter increments were taken into consideration. Species with bioeconomic potential, such as C. guianensis , H. courbaril, E. precatoria and M. flexuosa, were also classified as efficient and considered structuring species. • Periodic monitoring is a key factor in the study of forests under restoration. • Increase in height, diameter and survival rate are indicators of efficient. • Selecting adapted and fast-growing species are priorities for revegetation. • 35 species are suitable for post-mining restoration of tin in the central Amazon. [ABSTRACT FROM AUTHOR]

• Applied nucleation is effective to accelerate ecological restoration. • Applied nucleation accelerates the successional trajectory. • The development and expansion of the nuclei are satisfactory. • Ecological succession in intra-núcleos plots presents advances. Ecological restoration is a process that helps restore a degraded, damaged, or destroyed ecosystem. Applied nucleation is considered a strategy that facilitates the development of vegetation, attracts dispersers, and, over time, tends to expand, coalescing into continuous forests. However, simply implementing restorative techniques is not enough, it is also necessary to monitor the process. Monitoring requires good ecological indicators, which is a challenge for ecological restoration. The present study aims to evaluate, through ecological indicators, the effectiveness of the applied nucleation for restoration of riparian forest. The study was carried out in the Serra do Sudeste, Pampa region, southern Brazil. Ecological indicators were analyzed in two areas of restoration: passive and active restoration. In the area under active restoration, paired plots were evaluated: intra-nuclei (inside the nuclei) and inter-nuclei (outside the nuclei). To assess natural regeneration, all regenerant shrubby and arboreal individuals taller than 30 cm were counted and taxonomically identified. The species were classified according to the dispersal syndrome. Shannon diversity indices and Pielou evenness were calculated. The canopy cover of nuclei and trees planted crown cover were evaluated. Ecological indicators were compared using Tukey's test (p < 0.05). The results showed a significant difference between passive, intra-nuclei, and inter-nuclei restorations for the evaluated indicators, with higher averages for intra-nuclei, followed by inter-nuclei and passive restorations. It is concluded that the intra-nuclei plots showed an increase in richness, abundance, biotic dispersal syndrome, canopy cover, and soil cover by plant litter and arboreal species. The applied nucleation is an effective strategy for ecological restoration in the study region. [ABSTRACT FROM AUTHOR]

Natural Areas Association b will hold its one-day virtual 2023 conference, The Power of Long Term Ecological Research (LTER): Informing natural areas management. Graph Click for larger view View full resolution B Argentine black and white tegu (Salvator meriane). International Symposium on Ecological Restoration Practices & Ecological Restoration of Argentina b in Neuquén, Argentina. [Extracted from the article]

Tamarix spp. are ecological threats in the Southwest U.S.A. because they displace native vegetation, increase soil salinity, and negatively affect soil microbial communities. After Tamarix L. removal, legacy effects often necessitate restoration to improve ecosystem services of Tamarix-impacted communities. Commercial mycorrhizae fungal inoculation has been recommended to improve restoration success, although inoculation treatments are rarely tested on lesser-known facultative riparian species. Our study asked two questions: (1) Can a commercial mycorrhizal fungal inoculant increase native Baccharis salicifolia (Ruiz & Pav.) Pers. (mule-fat) performance against Tamarix chinensis Lour. (i.e., tamarisk) and is this influenced by tamarisk leaf litter? (2) Is mycorrhizal colonization of mule-fat roots influenced by tamarisk stem density and leaf litter? A greenhouse experiment was performed with mule-fat cuttings in soil collected from a tamarisk monoculture. Treatments were factorial combinations of tamarisk stem densities (0, 1, 2, 3, 4 stems pot−1) with or without mycorrhizal inoculation and tamarisk litter. There were five replications and two greenhouse runs. The total biomass of both species was determined and mule-fat arbuscular mycorrhizal colonization rates were determined via the magnified intersection method. Increasing tamarisk biomass negatively affected mule-fat biomass, but there were interactions with tamarisk biomass, litter and mycorrhizal inoculation, with litter and inoculation increasing mule-fat growth at high tamarisk biomass. Arbuscular mycorrhizal colonization was high in all treatments, yet at higher tamarisk stem densities, inoculation and litter improved colonization. Interestingly, litter did not negatively impact mule-fat as predicted. Moreover, litter and mycorrhizal inoculum interacted with tamarisk to improve mule-fat growth at higher tamarisk biomass, suggesting an opportunity to improve restoration success when in competition with tamarisk.

Riparian restoration is an important objective for landscape managers seeking to redress the widespread degradation of riparian areas and the ecosystem services they provide. This study investigated the long-term outcomes of ‘one-off’ restoration activities undertaken in the Upper Murrumbidgee Catchment, NSW, Australia. The objective of the restoration was to protect and enhance riparian vegetation and control erosion, and consequently reduce sediment and nutrient delivery into the Murrumbidgee River. To evaluate the outcomes 10 years after restoration, rapid riparian vegetation and geomorphological assessments were undertaken at 29 sites spanning the four different restoration methods used (at least five replicates per treatment), as well as at nine comparable untreated sites. We also trialed the use of aerial imagery to compare width of riparian canopy vegetation and projective foliage cover prior to restoration with that observed after 10 years. Aerial imagery demonstrated the width of riparian canopy vegetation and projective foliage cover increased in all restored sites, especially those with native plantings. The rapid assessment process indicated that 10 years after riparian restoration, the riparian vegetation was in a better condition at treated sites compared to untreated sites. Width of riparian canopy vegetation, native mid-storey cover, native canopy cover and seedling recruitment were significantly greater in treated sites compared to untreated sites. Geomorphological condition of treated sites was significantly better than untreated sites, demonstrating the importance of livestock exclusion to improve bank and channel condition. Our findings illustrate the value of ‘one-off’ restoration activities in achieving long-term benefits for riparian health. We have demonstrated that rapid assessments of the vegetation and geomorphological condition can be undertaken post-hoc to determine the long-term outcomes, especially when supported with analysis of historical aerial imagery.

Many large rivers around the world no longer flow to their deltas, due to ever greater water withdrawals and diversions for human needs. However, the importance of riparian ecosystems is drawing increasing recognition, leading to the allocation of environmental flows to restore river processes. Accurate estimates of riparian plant evapotranspiration (ET) are needed to understand how the riverine system responds to these rare events and achieve the goals of environmental flows. In 2014, historic environmental flows were released into the Lower Colorado River at Morelos Dam (Mexico); this once perennial but now dry reach is the final stretch to the mighty Colorado River Delta. One of the primary goals was to supply native vegetation restoration sites along the reach with water to help seedlings establish and boost groundwater levels to foster the planted saplings. Patterns in ET before, during, and after the flows are useful for evaluating whether this goal was met and understanding the role that ET plays in this now ephemeral river system. Here, diurnal fluctuations in groundwater levels and Moderate Resolution Imaging Spectroradiometer (MODIS) data were used to compare estimates of ET specifically at 3 native vegetation restoration sites during 2014 planned flow events, and MODIS data were used to evaluate long-term (2002-2016) ET responses to restoration efforts at these sites. Overall, ET was generally 0-10 mm d−1 across sites, and although daily ET values from groundwater data were highly variable, weekly averaged estimates were highly correlated with MODIS-derived estimates at most sites. The influence of the 2014 flow events was not immediately apparent in the results, although the process of clearing vegetation and planting native vegetation at the restoration sites was clearly visible in the results. [ABSTRACT FROM AUTHOR]

Floodplain riparian ecosystems support unique vegetation communities and high biodiversity relative to terrestrial landscapes. Accordingly, estimating riparian ecosystem health across landscapes is critical for sustainable river management. However, methods that identify local riparian vegetation condition, an effective proxy for riparian health, have not been applied across broad, regional extents. Here we present an index to assess reach-scale (500 m segment) riparian vegetation condition across entire drainage networks within large, physiographically-diverse regions. We estimated riparian vegetation condition for 53,250 km of perennial streams and rivers, 25,685 km in Utah, and 27,565 km in twelve watersheds of the interior Columbia River Basin (CRB), USA. We used nationally available, existing land cover classification derived from 30 m Landsat imagery (LANDFIRE EVT) and a modeled estimate of pre-European settlement land cover (LANDFIRE BpS). The index characterizes riparian vegetation condition as the ratio of existing native riparian vegetation cover to pre-European settlement riparian vegetation cover at a given reach. Roughly 62% of Utah and 48% of CRB watersheds showed significant (>33%) to large (>66%) departure from historic condition. Riparian vegetation change was predominantly caused by human land-use impacts (development and agriculture), or vegetation change (native riparian to invasive or upland vegetation types) that likely resulted from flow and disturbance regime alteration. Through comparisons to ground-based classification results, we estimate the existing vegetation component of the index to be 85% accurate. Our assessments yielded riparian condition maps that will help resource managers better prioritize sites and treatments for reach-scale conservation and restoration activities. [ABSTRACT FROM AUTHOR]

Land use change in riparian zones is one of the most significant threats to water quality in watershed ecosystems. Riparian forests play a major role in protecting water quality, and there is a need to assess the role of riparian restoration in reducing nutrients and sediment loading. This study uses watershed simulation modeling to evaluate impacts of riparian forest restoration on water quality in a tropical agricultural watershed. Soil Water Assessment Tool (SWAT) is used to simulate streamflow, suspended sediment and nutrients of the Sarapuí River watershed, located in southeast Brazil. We observe a spatial and temporal variation in water quality impacts of changes in land use/land cover (LULC) and rainfall patterns. Watersheds with agricultural and some residential areas had a higher sediment and nutrients loads than forest and with pasture land uses, especially during the wet season. Forested watersheds in general had a better water quality than other LULC types. Riparian restoration in the study watershed can reduce suspended sediment (9.26%), total nitrogen (22.6%), and total phosphorus (7.83%). Protecting riparian zone and site-conservation practices is critical to improve water quality. We observe that the simulation model provides a satisfactory baseline of the watershed system to evaluate impacts of land use changes. [ABSTRACT FROM AUTHOR]

River restoration ( RR) is widely practiced in both rural and urban contexts by combining various goals and measures. The theoretical discourse on RR not yet adequately reflects this breadth of restoration practice. In this study, we investigated 110 French RR projects implemented between 1980 and 2015. We analyzed projects considering eight key design features, main project motivation, restoration goals, project dates, costs, size, funding, river annual discharge, and implemented evaluation procedures. The study (1) provides a detailed account of the French RR effort, (2) compares restoration efforts in urban and rural contexts, and (3) establishes a RR project typology. The results also show that urban RR comprises a wider range of goals and measures than its rural counterpart, includes restoration of riparian habitats, and integrates ecological and social goals. A hierarchical multiple factor analysis yielded five types of projects, Fish RR (14% of the urban and 53% of the rural projects), Blue RR (4%, 7%), Water Framework Directive RR (36%, 40%), Flood protection RR (14%, 0%), and Human RR (32%, 0%). We suggest that the restoration community needs databases that use a project typology as developed in this study. This approach would take into account the multiple facets of RR projects, enabling more transparency into their communication and allow more suitable project comparisons. [ABSTRACT FROM AUTHOR]

Riparian systems are threatened globally, but contribute disproportionately to biodiversity and ecosystem function. Restoration to reverse their loss is costly, and requires careful monitoring and evaluation. Odonates are amongst the most reliable arthropod bio-indicators for monitoring riparian ecosystems. Despite functional diversity (FD) reflecting ecosystem pattern and processes better than taxonomic diversity, Odonate FD has yet to be used in evaluating riparian conservation and restoration outcomes. We surveyed 45 sites across six river-systems in northeastern South Africa, to compare Odonate FD and standardised effect size of Odonate FD (sesFD) in riparian systems that had been invaded by alien plants, cleared of alien invasives, and sites that had never been invaded (15 sites each). Although species richness did not differ between treatments, Odonate sesFD was lower in invaded sites than those that had been cleared of alien riparian vegetation and those that had never been invaded. Clearance of 40% of alien riparian vegetation was associated with sesFD greater than that of invaded sites by almost two standard deviations. Representation of traits varied between treatments but was similar between cleared and natural sites, suggesting that invasion by alien plants directly impacts food webs, and that clearance can restore ecosystem processes and ecological services. This study confirms that Odonate FD can respond to restoration efforts. Secondary impacts of restoration to complete suites of functional groups can be anticipated to enhance ecological services and impact food webs at a range of scales. [ABSTRACT FROM AUTHOR]

In the present context of global change and search for sustainability, we detected a gap between restoration and society: local communities are usually only considered as threats or disturbances when planning for restoration. To bridge this gap, we propose a landscape design framework for planning riparian rehabilitation in an urban-rural gradient. A spatial multi-criteria analysis was used to assess the priority of riversides by considering two rehabilitation objectives simultaneously-socio-environmental and ecological-and two sets of criteria were designed according to these objectives. The assessment made it possible to identify 17 priority sites for riparian rehabilitation that were associated with different conditions along the gradient. The double goal setting enabled a dual consideration of citizens, both as beneficiaries and potential impacts to rehabilitation, and the criteria selected incorporated the multi-dimensional nature of the environment. This approach can potentially be adapted and implemented in any other anthropic-natural interface throughout the world. [ABSTRACT FROM AUTHOR]

Degradation, impoundment, and channelization of streams is a global problem. Although stream restoration projects have increased in recent years, post-restoration, long-term monitoring is rare. In 2003, a channelized section of Wilson Creek (Nelson Co., Kentucky) was restored by creating a meandering channel, re-connecting the channel to its floodplain, and planting native riparian species: giant cane and bottomland forest species. Our main objective was to conduct a ten-year post-restoration assessment to determine long-term restoration outcomes of channel water quality, growth of trees planted in the riparian area, and soil development. Water quality, soil, and tree data collected in 2013-2015 was compared to 2004-2006 data. Quality of water parameters changed over time: sulfate, magnesium, calcium, potassium, alkalinity, pH, iron, and temperature decreased, whereas dissolved oxygen increased. Overall, soil pH, extractable ammonium, extractable nitrate, total carbon (TC), and total nitrogen (TN) increased over time. Effects were observed in restored riparian areas for pH, extractable ammonium, and TC; while TC and TN exhibited depth-dependent interactions. The carbon-nitrogen ratio in these soils significantly decreased over time for the reference sites, and the treatments recovered to near reference level. Platanus occidentalis (American sycamore) and Fraxinus pennsylvanica (green ash) individuals had higher survival (80% and 79%, respectively) than individuals of Quercus palustris (pin oak; 22%). Shelter and herbicide treatments had no effect on tree survival or height growth; however, height growth varied by species. Platanus occidentalis exhibited a greater than five-fold increase, F. pennsylvanica slightly increased, and Q. palustris decreased in height growth. Overall, water and soil quality improved over time at the restoration site, while tree survival and height growth exhibited species-specific outcomes. [ABSTRACT FROM AUTHOR]

Minute 319, a binational agreement between the United States and México, authorized environmental flows into the Colorado River Delta, including a high-profile pulse flow delivered in March through May 2014. Reforming water management policy to secure future delivery of environmental flows to the delta hinges on demonstrating the feasibility of delivering environmental water and documenting positive ecological responses of the delta’s severely degraded riparian habitat. The design of the flow’s hydrograph, the novel utilization of irrigation infrastructure, the preparation and subsequent maintenance of selected restoration sites, and interdisciplinary monitoring at multiple scales combined to show that ecological restoration is possible, even with extremely small water volumes compared to historical flows. The overwhelmingly positive social responses to the flow are likely as pivotal to future flows as are the biophysical responses. The pulse flow’s unique binational character demanded exceptional collaboration and communication involving local, state, and federal government agencies; water managers; water users; scientists; and non-governmental organizations. The success of such a politically, operationally, and scientifically complex endeavor in the severely over-allocated Colorado River Basin bodes well for the future of environmental flows in its delta and in other water-stressed settings, worldwide. [ABSTRACT FROM AUTHOR]

Managing streamflow is a widely-advocated approach to provide conditions necessary for seed germination and seedling establishment of trees in the willow family (Salicaceae). Experimental flow releases to the Colorado River delta in 2014 had a primary objective of promoting seedling establishment of Fremont cottonwood ( Populus fremontii ) and Goodding's willow ( Salix gooddingii ). We assessed seed germination and seedling establishment of these taxa as well as the non-native tamarisk ( Tamarix spp.) and native seepwillow shrubs ( Baccharis spp.) in the context of seedling requirements and active land management (land grading, vegetation removal) at 23 study sites along 87 river km. In the absence of associated active land management, experimental flows to the Colorado River delta were minimally successful at promoting establishment of new woody riparian seedlings, except for non-native Tamarix . Our results suggest that the primary factors contributing to low seedling establishment varied across space, but included low or no seed availability in some locations for some taxa, insufficient soil moisture availability during the growing season indicated by deep groundwater tables, and competition from adjacent vegetation (and, conversely, availability of bare ground). Active land management to create bare ground and favorable land grades contributed to significantly higher rates of Salicaceae seedling establishment in a river reach with high groundwater tables. Our results provide insights that can inform future environmental flow deliveries to the Colorado River delta and its ecosystems and other similar efforts to restore Salicaceae taxa around the world. [ABSTRACT FROM AUTHOR]

Environmental flows have become important restoration tools on regulated rivers. However, environmental flows are often constrained by other demands within the river system and thus typically are comprised of smaller water volumes than the natural flows they are meant to replace, which can limit their functional efficacy. We review environmental flow programs aimed at restoring riparian vegetation on four arid zone rivers: the Tarim River in China; the Bill Williams River in Arizona, U.S.; the delta of the Colorado River in Mexico; and the Murrumbidgee River in southern Australia. Our goal is to determine what worked and what did not work to accomplish restoration goals. The lower Tarim River in China formerly formed a “green corridor” across the Taklamakan Desert. The riparian zone deteriorated due to diversion of surface and groundwater for irrigated agriculture. A massive restoration program began in 2000 with release of 1038 million cubic meters of water over the first three years. Groundwater levels rose but the ecological response was less than expected politically, socially and within the scientific community. However, releases continued and by 2015 portions of the original iconic Populus euphratica (Euphrates poplar) forest were reestablished. The natural flow regime of the Bill Williams River was disrupted by construction of a dam in 1968, dramatically reducing peak flows along with associated fluvial processes. As a result, the channel narrowed and riparian vegetation expanded and was comprised largely of an introduced shrub species ( Tamarix spp.). Environmental flow releases including small, managed floods and sustained base flows have been implemented since the mid 1990’s to promote establishment and maintenance of native riparian trees (cottonwoods and willows) and have been successful, although in a “downsized” portion of the valley bottom. Experience from the Bill Williams was used to help design the Minute 319 environmental flow in the delta of the Colorado River in 2014. Water was released as a short, one-time pulse during spring with the intent of starting new cohorts of cottonwood and willow. However, fluvial disturbance was limited by the relatively small magnitude pulse, low flows did not continue throughout the growing season in some reaches, native tree recruitment was low, and most of the new plants recruited were Tamarix . The inundated portion of the floodplain did respond with a temporary increase in greenness as measured by satellite vegetation indices, however. The Murrumbidgee River in Australia is a tributary in the Murray-Darling River Basin, which supports iconic red gum ( Eucalyptus camaldulensis ) forests that depend on near-yearly floods for maintenance. During the recent Millennial Drought (2000–2010) environmental flows were provided on an experimental basis to small portions of the Yanga National Forest to see how much water was needed. As with the Colorado River delta, gains in vegetation vigor as measured by satellite vegetation indices following the flows were temporary. Environmental flows in the Bill Williams were able to restore enough overbank flooding and fluvial disturbance to promote some establishment of new cohorts of trees, but on the Colorado and Murrumbidgee Rivers larger volumes of total flows released over longer periods and targeted restoration will be needed to restore the ecosystems. A measure of success in restoring the Euphrates poplar forest on the Tarim and germinating new chorts of willows on the Bill Williams has been achieved after 15–20 years of environmental flows, but the Colorado River delta and Murrumbidgee Rivers have only received one or two flows. Success in enhancing native trees in the Colorado delta has been achieved in restoration plots, but the Murrumbidgee will require large overbank flows on a continuing schedule to rejuvenate the red gum forest. [ABSTRACT FROM AUTHOR]

Increasing pressure on water availability in the Colorado River Basin due to a long and severe drought, water over-allocation, increasing water demands, and a warming climate point toward the need to optimize use of water to meet all goals, including environmental restoration. In this paper, we analyze the hydrologic response of the Colorado River Delta to the 2014 pulse flow. In so doing, we identify hydrological criteria for optimizing the use of water for riparian restoration. We analyzed continuous hydrographs obtained from discharge measurement sites along the river channel, quantified areas inundated by water, and interpreted groundwater dynamics and their implications for riparian vegetation. Our most important finding is that 91.4% of the delivered water infiltrated into the first 61.2 km of the riverbed (between Morelos Dam and Pescaderos), recharging the underlying aquifer. This large volume of infiltration occurred mainly because several obstructions along the main channel impeded downstream surface flow, abandoned river meanders acted as infiltration basins, sandy riverbed and terrace sediments allowed for rapid infiltration, and a depressed groundwater table created a large unsaturated zone to fill. Most of the water was delivered at Morelos Dam. However, smaller water deliveries via Mexicali Valley’s irrigation canal system bypassed the reaches of maximum infiltration, enabling the achievement of longitudinal river connectivity from Morelos Dam to the Gulf of California, and inundating important flood-dependent restoration sites. To optimize future environmental water deliveries, we encourage the use of irrigation infrastructure to deliver water directly to specific restoration sites to the extent possible, thereby avoiding reaches with high infiltration capacity and low riparian restoration potential. To improve river channel functionality in high-infiltration reaches, we recommend strategies to flood only the main channel and avoid off-channel depressions. By considering hydrological responses to environmental flow deliveries, riparian restoration goals can be achieved efficiently, even in highly controlled rivers with limited water availability. [ABSTRACT FROM AUTHOR]

Drastic alterations to river hydrology, land use change, and the spread of the nonnative shrub, tamarisk ( Tamarix spp.), have led to the degradation of riparian habitat in the Colorado River Delta in Mexico. Delivery of environmental flows to promote native cottonwood ( Populus spp.) and willow ( Salix spp.) recruitment in human-impacted riparian systems can be unsuccessful due to flow-magnitude constraints and altered abiotic–biotic feedbacks. In 2014, an experimental pulse flow of water was delivered to the Colorado River in Mexico as part of the U.S.-Mexico binational agreement, Minute 319. We conducted a field experiment to assess the effects of vegetation removal, seed augmentation, and environmental flows, separately and in combination, on germination and first-year seedling establishment of cottonwood, willow, and tamarisk at five replicate sites along 5 river km. The relatively low-magnitude flow deliveries did not substantively restore natural fluvial processes of erosion, sediment deposition, and vegetation scour, but did provide wetted surface soils, shallow groundwater, and low soil salinity. Cottonwood and willow only established in wetted, cleared treatments, and establishment was variable in these treatments due to variable site conditions and inundation duration and timing. Wetted soils, bare surface availability, soil salinity, and seed availability were significant factors contributing to successful cottonwood and willow germination, while soil salinity and texture affected seedling persistence over the growing season. Tamarisk germinated and persisted in a wider range of environmental conditions than cottonwood and willow, including in un-cleared treatment areas. Our results suggest that site management can increase cottonwood and willow recruitment success from low-magnitude environmental flow events, an approach that can be applied in other portions of the Delta and to other human-impacted riparian systems across the world with similar ecological limitations. [ABSTRACT FROM AUTHOR]

Due to climate change and its consequences to islands and coastal countries, the relocation of the people living in those vulnerable places has received a lot of attention from policy makers as well as academicians. There have been similar kinds of programs running in Bangladesh since the country's independence in 1971, and people who are landless or victimized due to river bank erosion, cyclones, or floods have been relocated under the umbrella program called 'Guchchagram', i.e., cluster villages. Different ruling parties had used different names for the project due to the financial nature of the project, but none of them have significantly differed from the overall goals and objectives of relocated settlements and the betterment of the landless and extreme event victims. Particularly, this study asks how and to what extent the livelihood of relocated households has changed, and what the potentials and constraints of the relocated settlements are. Based on an empirical study at four Guchchagrams of Gopalganj Sadar Upazila, the study shows that there is a significant improvement in the livelihood conditions of the migrated people, but the locational disadvantages and access to agricultural production, the local employment market, and some of the targeted objectives of the project have not achieved. To some extent, the rehabilitated families have similar risks as they had before; however, available agricultural lands and proper allocation can reduce such livelihood risks. [ABSTRACT FROM AUTHOR]