Riverine Ecosystem Services Research Articles

Non‐Native Invasive Fish Species (NIFS) in Inland Waters of India: Management Issues, Strategies and Suggestions

ABSTRACTIn India, there are 626 non‐native invasive fish species (NIFS), with 16 becoming invasive in inland waters, adversely impacting native biodiversity, and fisheries by altering the abundance of NIFS in commercial catches. Scientific findings highlight that the movement of NIFS interacts with agricultural activities and the evolving environment, facilitating their spread and establishment. The scenario of NIFS invasion disrupts biological communities, ecosystem services and fisherfolk livelihoods. Despite the implementation of existed guidelines, issues related to NIFS have persisted and escalated over time scale putting increased pressure on indigenous aquatic biological resources in inland waters. This paper suggests the need of framing a new management plans, guidelines and regulatory policies to control NIFS invasions, protecting riverine fish biodiversity and ecosystem services. Proposed management strategies include functional response (FR) and adaptive response (AR)‐based approaches, which are discussed to address NIFS management in inland waters.

Streamflow Intermittence in Europe: Estimating High‐Resolution Monthly Time Series by Downscaling of Simulated Runoff and Random Forest Modeling

AbstractKnowing where and when rivers cease to flow provides an important basis for evaluating riverine biodiversity, biogeochemistry and ecosystem services. We present a novel modeling approach to estimate monthly time series of streamflow intermittence at high spatial resolution at the continental scale. Streamflow intermittence is quantified at more than 1.5 million river reaches in Europe as the number of no‐flow days grouped into five classes (0, 1–5, 6–15, 16–29, 30–31 no‐flow days) for each month from 1981 to 2019. Daily time series of observed streamflow at 3706 gauging stations were used to train and validate a two‐step random forest modeling approach. Important predictors were derived from time series of monthly streamflow at 73 million 15 arc‐sec (∼500 m) grid cells that were computed by downscaling the 0.5 arc‐deg (∼55 km) output of the global hydrological model WaterGAP, which accounts for human water use. Of the observed perennial and non‐perennial station‐months, 97.8% and 86.4%, respectively, were correctly predicted. Interannual variations of the number of non‐perennial months at non‐perennial reaches were satisfactorily simulated, with a median Pearson correlation of 0.5. While the spatial prevalence of non‐perennial reaches is underestimated, the number of non‐perennial months is overestimated in dry regions of Europe where artificial storage abounds. Our model estimates that 3.8% of all European reach‐months and 17.2% of all reaches were non‐perennial during 1981–2019, predominantly with 30–31 no‐flow days. Although estimation uncertainty is high, our study provides, for the first time, information on the continent‐wide dynamics of non‐perennial rivers and streams.

Resilient riverine social–ecological systems: A new paradigm to meet global conservation targets

AbstractThe United Nations' Convention on Biological Diversity set forth the 30 × 30 target, an agenda for countries to protect at least 30% of their terrestrial, inland water, and coastal and marine areas by 2030. With <6 years to reach that goal, riverine conservation professionals are faced with the difficult decision of prioritizing which rivers or river segments should be conserved (protected and/or restored). While incorporating resilience into conservation planning is essential for enhancing, restoring, and maintaining the vital riverine ecosystem services (ES) most threatened by climate change and other environmental and human stresses, this paradigm is at odds with traditional conservation approaches that are either opportunistic or reactionary, where only unique and highly visible ecosystems have been prioritized. Barriers to implementing resilience‐based riverine conservation planning include: (1) difficulties in conceptualizing and quantifying resilience; (2) insufficient consideration of the social components of riverine systems; (3) the inapplicability of terrestrial‐only conservation models to aquatic systems; and (4) the traditional ad hoc and opportunistic approach to conservation. To overcome these barriers, we propose a resilience‐based riverine conservation framework that includes: (1) assessing riverine resilience using indicator frameworks; (2) considering rivers as dynamically coupled social–ecological systems; (3) explicitly incorporating terrestrial–aquatic network connectivity into conservation decision‐making; and (4) strategic systems planning using a novel resilience–conservation matrix as a tool. This framework has the potential to transform conservation practices around the globe to more effectively protect river systems and enhance their resilience to climate change and human development.This article is categorized under: Water and Life > Conservation, Management, and Awareness Science of Water > Water and Environmental Change Human Water > Water Governance

The value of improving freshwater ecosystem services: South Carolina residents’ willingness to pay for improved water quality

Riverine ecosystems play a crucial role in providing essential services such as drinking water, food, recreation, and other aquatic resources. Yet, their capacity to deliver ecosystem services is threatened by rapid land use which modifies their ecological functions. While freshwater monitoring and restoration programs became more robust with technological advancement, the technical ecosystem indicators monitored by experts do not typically resonate with the public. Since public sentiments and preferences are crucial in conservation planning, we quantified households' mean willingness to pay (WTP) for riverine ecosystem services in South Carolina (SC) using a payment card approach. This technique in conducting a contingent valuation method allowed us to estimate mean WTP for five aquatic indicators. Findings revealed that households’ monthly mean WTP is higher for indicators that can enhance recreational benefits, such as fish catch ($5.89- $6.58), species richness ($6.28- $6.72) and access ($6.75) compared to IBI ($5.74- $6.26) and instream flow quality ($5.34–6.06). When extrapolated to entire SC, the improvement of each indicator would translate to total benefits ranging between $131 to $165 million annually. The values computed from this study could serve as inputs for the computation of benefit-cost ratios of proposed freshwater programs. By incorporating households' WTP in the policy analysis, decision makers can prioritize programs that offer the greatest public benefit, while enhancing freshwater quality across the state.

Reconstructing valley landscapes. GIS-analyses of past land use changes in three Flemish river valleys since the late 18th century

The restoration of riverine ecosystem services and floodplain landscapes has become an important tool in climate mitigation, however, it is often unclear what landscape a restoration is (or should be) referring to. Little is known moreover, about long-term transitions in historic valley land use or how they echo in contemporary perceptions of floodplain landscapes. Also in densely populated Flanders (in the north of Belgium), where floodplains are quickly losing their natural functions, policymakers are actively in pursuit of climate change adaptation strategies and sustainable valley management. We present the results of a GIS-based reconstruction of historical land use in three Flemish river valleys from 1771 to 2002 and compare them to changes in regional land use. We find that while grasslands initially and to a vast extent covered our selected floodplains, the latter were by the mid-19th century cultivated for agricultural production, in line with a global expansion of arable land and regional demographic growth. Also forest cover in the studied river valleys grew exponentially from the late 19th century, unmatched by regional forest cover. After the Second World War, a denser road network, more area that is built-up and forest plantations visually contributed to valley compartmentalisation and the perception of a closed landscape. Varying soil textures and drainage levels or the (in)ability to manage them properly accounted for different(ly) (timed) land use changes between the studied floodplain areas. Regional changes in historic land use were of lesser importance.

Basin-scale riverine ecosystem services vary with network geometry

Riverine ecosystems provide a variety of services supporting biodiversity, human livelihoods, and the maintenance of river health. Multiple anthropogenic threats to riverine ecosystem services (RES) have been identified and considered in river management strategies. However, the way in which the river network is spatially arranged across the landscape – river network geometry – may also play a role in the delivery of RES. Here we studied the effect of river network geometry on the delivery of five RES in 14 catchments of the Great Barrier Reef region, Australia. Our investigation has three parts. First, we conducted a sensitivity analysis on modelled RES, holding all non-geometric catchment characteristics, other than catchment size and slope, constant to allow attribution of modelled differences directly to differences in geometry. Second, we analysed the relationships between observed RES and network structural indices. Third we compared observed RES with modelled results. Modelled results suggest that RES are sensitive to the differences in river network geometry. Furthermore, correlation analyses show good agreement between observed RES and network structural indices, and there is good correlation between the modelled and observed RES. These results suggest an important role of river network geometry in the delivery of multiple RES by mediating upstream inputs as they pass through the river network. A one size fits all approach to river management may thus be ineffective and specific management interventions will be needed in catchments of different network geometries.

A multiscale model for solute transport in stream corridors with unsteady flow

The transport of solutes in stream corridors is an important process for riverine biogeochemistry and ecosystem services. This process is largely controlled by bulk movement in the stream channel and mass exchange with the hyporheic zone. However, modeling solute transport in stream corridors under dynamic hydrological conditions remains a scientific challenge. Here, we extend a steady-state Lagrangian multiscale river-corridor transport model to accommodate unsteady flow. The extended numerical model was evaluated with observations of conservative tracer at a headwater mountain stream using Markov-Chain Monte Carlo method to estimate model parameters and quantify uncertainty. Parameter estimation was exposed to a range of unsteady flow conditions through joint fitting of tracer data observed at different intervals of the base flow recession. This yielded a robust scaling of hyporheic parameters with time-varying streamflow which is evident from the good fit between modeled outputs and observations. The proposed approach enables Lagrangian-based modeling of solute transport under dynamic flow regimes, e.g., storm-affected flow where discharge inevitably changes over time. It also paves way for extending Lagrangian-based transport models to catchment and larger spatial scales.

The Heterogeneity of Ecosystem Services across the Riverine Landscape of the Koshi River Basin, Nepal

A foundational tenet of the ecosystem services concept is that they arise from biophysical processes. Riverine landscapes are process-response systems where river flow and geomorphology generate a heterogeneous physical template that influences ecological processes, suggesting that the supply of ecosystem services in riverine landscapes should be congruent with the character and heterogeneity of the physical template. In this study, we examine the congruency between the physical template (river functional process zones; FPZs) and the supply of river flow dependent ecosystem services from riverine landscapes of the Koshi River Basin, Nepal. The supply of ecosystem services was congruent with FPZs. Social factors were shown to mediate the use and value of ecosystem services between FPZs. Heterogeneity of the physical template interacts with place, social activity, and demography to influence the use and potential value of ecosystem services across the riverine landscape. These spatial patterns of greater use of some types of riverine ecosystem services in certain areas of the riverine landscape are indicative of a highly coupled agricultural or “green loop” social-ecological system (SES) and show that maintaining riverine template heterogeneity is an important element of this green loop SES that supports 40 million people in the Koshi River Basin.

The Social, Economic, and Ecological Drivers of Planning and Management of Urban River Parks

Urban rivers deliver a broad range of contributions of nature to human development. The exploitation of the riverine ecosystem services evolves with uncertainty. In addition to the current decreasing of ecosystem health and changing climate, the impact of societal development on the river system directly reduces the potential delivery of future ecosystem services. What are the drivers of the design of urban river parks and what upcoming challenges will need to be addressed? This paper presents the results of an ex-post-analysis and comparative analysis of planning orientations of two urban river parks, the Isar River in Munich (Germany) and the American River in Sacramento (U.S.). The contribution describes the evolution of the urban rivers based on planning strategy, identifies drivers of changes and discusses the upcoming challenges for urban river parks that need to be addressed in the short and long term. The contribution shows that urban river park designs occur in a larger context of human demographic, technological, and economic changes. The contribution does not intend to solve the very complex and urgent challenges the case study sites face but rather to highlight research needs to support adaptation strategies.

Using weighted expert judgement and nonlinear data analysis to improve Bayesian belief network models for riverine ecosystem services

Rivers are a key part of the hydrological cycle and a vital conduit of water resources, but are under increasing threat from anthropogenic pressures. Linking pressures with ecosystem services is challenging because the processes interconnecting the physico-chemical, biological and socio-economic elements are usually captured using heterogenous methods. Our objectives were, firstly, to advance an existing proof-of-principle Bayesian belief network (BBN) model for integration of ecosystem services considerations into river management. We causally linked catchment stressors with ecosystem services using weighted evidence from an expert workshop (capturing confidence among expert groups), legislation and published literature. The BBN was calibrated with analyses of national monitoring data (including non-linear relationships and ecologically meaningful breakpoints) and expert judgement. We used a novel expected index of desirability to quantify the model outputs. Secondly, we applied the BBN to three case study catchments in Ireland to demonstrate the implications of changes in stressor levels for ecosystem services in different settings. Four out of the seven significant relationships in data analyses were non-linear, highlighting that non-linearity is common in ecosystems, but rarely considered in environmental modelling. Deficiency of riparian shading was identified as a prevalent and strong influence, which should be addressed to improve a broad range of societal benefits, particularly in the catchments where riparian shading is scarce. Sediment load had a lower influence on river biology in flashy rivers where it has less potential to settle out. Sediment interacted synergistically with organic matter and phosphate where these stressors were active; tackling these stressor pairs simultaneously can yield additional societal benefits compared to the sum of their individual influences, which highlights the value of integrated management. Our BBN model can be parametrised for other Irish catchments whereas elements of our approach, including the expected index of desirability, can be adapted globally.

Multifunctional resilience of river health to human service demand in an alluvial quarried reach: a comparison amongst fuzzy logic, entropy, and AHP-based MCDM models.

Riverine ecosystem services to human beings are dynamically evaluated by harmonic relationships; however, over growing human service demands (HSDs) are leading to deteriorate the river health resilience. In this study, an assessment index system of river health involving pressure-state-response (PSR) based on twenty indicators of riparian, channel geomorphic, hydroecological, and social attributes was developed to detect the multifunctional reliability and resilience of river system integrity for HSDs at upper (US), middle (MS), and lower segments (LS) of Kangsabati River using fuzzy logic, analytical hierarchical process (AHP), and entropy weight-basedmulti-criteria decision matrix (MCDM) methods. Borda integrating MCDM results revealed that overall indicator performance is high health score in US (77), medium score in MS (69), but mostly unhealthy score in LS (34); thus, entropy-MCDM models give highest rank to US, medium rank to MS, and least rank to LS, while AHP and fuzzy MCDM models assigned as high priority rank to MS, medium rank to US, and least rank to LS, respectively. According to model validation performances, entropy-MCDM models (RMSE < 2.48) are rationalized to the harmonic relationship of riverine system, whereas fuzzy and AHP-MCDM models (RMSE < 2.79) are signified to HSDs, and these results are closer to real problems. With the acceptability of AHP-MCDM models through the percentage change (73.89%) and intensity change (17.16) assessment, it points that over HSDs are crucial factors for river health degradation. Moreover, final outcome of the present research helps to find out the sick river health sites for ecological restoration.

Habitat availability determines food chain length and interaction strength in food webs of a large lowland river

AbstractMany large rivers used for navigation have lost their hydromorphological heterogeneity, which has led to the widespread loss of native biodiversity and the concurrent establishment of non‐native communities. While the effects on biodiversity are well‐described, we know little about how the loss of natural habitats and the restructuring of communities cumulate into effects on riverine food webs. We constructed binary and ingestion webs for benthic macroinvertebrates and their resources in the Elbe River (Germany) and compared if food chain length, food web complexity, robustness, ingestion rates, and consumer‐resource interaction strength differ among three shoreline engineering practices. Food webs at profoundly altered shorelines were significantly less complex and had significantly shorter food chains than the food web at the semi‐natural shoreline. However, food web robustness to a simulated loss of species was comparable at all shorelines. Total ingestion rates were up to eight times lower at highly altered shorelines due to significantly lower ingestion rates by native species. Predator–prey interaction strength was comparable among shorelines due to higher shares of non‐native predators, indicating that non‐native predators can be functionally equivalent to native predators. We attributed the observed food web differences to the absence of complex habitats at profoundly altered shorelines and the accompanied absence of specialized consumers. Our study provides empirical evidence that hydromorphological modifications reduce the efficiency of food webs to control organic matter dynamics and may ultimately affect the provisioning of riverine ecosystem services.

Does the topology of the river network influence the delivery of riverine ecosystem services?

AbstractRiverine ecosystems provide important ecosystem services reflecting their unique forms and functions. While the effects of stressors such as land cover change, climate change and growing economies on riverine ecosystem services (RES) have been well researched, the effect of the structure of the river network itself is less understood. This paper compares the capacity of different river network topologies in the delivery of selected RES. For three contrasting synthetic river network topologies (Long Trellis Narrow; Coastal Dendritic; Inland Dendritic), we applied simple functional equations to model six RES: water supply, hydropower generation, sediment retention, nutrient uptake, flood attenuation and aquatic habitat provision. Results showed that the synthetic topologies deliver different levels of RES, driven by their differences in physical structure. For example, the Inland Dendritic network removed more nitrate and better attenuated flooding due to its relatively longer lower reaches but offered poorer prospects for water supply because the longer reaches were more susceptible to transmission losses (e.g., due to bed seepage). This study provides a valuable first step in understanding the effect of river network topology on RES delivery, and the relative strengths among network types. Understanding these effects can aid decision makers in the conservation and restoration of degraded river basins to preserve RES for future generations.

The current state of development of the no significant harm principle: How far have we come?

The duty to prevent significant transboundary harm remains a cornerstone principle of international law, and especially of international environmental and water resources law. However, this rule focuses on the conduct of a State where harm originates, rather than on the fact that harm has resulted from such conduct, and thus requires that States exercise due diligence in anticipating and in preventing or mitigating such harm. At a practical level, the due diligence standard of conduct expected of States can be uncertain and difficult to determine, as it must be deduced from the applicable primary rules of international environmental or water resources law, which have traditionally been elaborated in rather vague terms. In addition, the standard of due diligence required under the no-harm rule may be influenced by a range of variable and context-specific factors which might prove relevant in the particular circumstances of any dispute. Such uncertainty is further compounded in the field of international water law by the complex interrelationship between the no-harm rule and the other key norms of international water law, particularly the cardinal principle of equitable and reasonable utilization, which embodies a high degree of flexibility and adaptability and suffers from a corresponding degree of normative indeterminacy. Thankfully, recent developments in international water law and related practice regarding the requirement to protect riverine ecosystems and maintain related ecosystem services lend a welcome measure of clarity as regards the preventive measures expected of watercourse States under international law. Judicial recognition of obligations to maintain minimum environmental flows and to preserve or restore riverine ecosystem services, based on the proliferation of such values in treaty and declarative practice, along with the continuing development of sophisticated technical methodologies for ecosystems assessment and evaluation, do much to inform the due diligence conduct required of States. Such advances can only enhance the practical utility of the no-harm rule, and thus of the entire corpus of international water law, in addressing the challenges emerging globally for water resources management in the twenty-first century.

Identifying threshold responses of Australian dryland rivers to future hydroclimatic change

Rivers provide crucial ecosystem services in water-stressed drylands. Australian dryland rivers are geomorphologically diverse, ranging from through-going, single channels to discontinuous, multi-channelled systems, yet we have limited understanding of their sensitivity to future hydroclimatic changes. Here, we characterise for the first time the geomorphology of 29 dryland rivers with catchments across a humid to arid gradient covering >1,800,000 km2 of continental eastern and central Australia. Statistical separation of five specific dominantly alluvial river types and quantification of their present-day catchment hydroclimates enables identification of potential thresholds of change. Projected aridity increases across eastern Australia by 2070 (RCP4.5) will result in ~80% of the dryland rivers crossing a threshold from one type to another, manifesting in major geomorphological changes. Dramatic cases will see currently through-going rivers (e.g. Murrumbidgee, Macintyre) experience step changes towards greater discontinuity, characterised by pronounced downstream declines in channel size and local termination. Expanding our approach to include other river styles (e.g. mixed bedrock-alluvial) would allow similar analyses of dryland rivers globally where hydroclimate is an important driver of change. Early identification of dryland river responses to future hydroclimatic change has far-reaching implications for the ~2 billion people that live in drylands and rely on riverine ecosystem services.

Suitable landscape classification systems for quantifying spatiotemporal development of riverine ecosystem services

AbstractRiver systems provide numerous ecosystem services that contribute to human well-being. Biophysical quantification of spatiotemporal development of ecosystem services is useful for environme...

A review of riverine ecosystem service quantification: Research gaps and recommendations

Abstract Increasing demand for benefits provided by riverine ecosystems threatens their sustainable provision. The ecosystem service concept is a promising avenue to inform riverine ecosystem management, but several challenges have prevented the application of this concept. We quantitatively assess the field of riverine ecosystem services’ progress in meeting these challenges. We highlight conceptual and methodological gaps, which have impeded integration of the ecosystem service concept into management. Across 89 relevant studies, 33 unique riverine ecosystem services were evaluated, for a total of 404 ecosystem service quantifications. Studies quantified between 1 and 23 ecosystem services, although the majority (55%) evaluated three or less. Among studies that quantified more than one service, 58% assessed interactions between services. Most studies (71%) did not include stakeholders in their quantification protocols, and 34% developed future scenarios of ecosystem service provision. Almost half (45%) conducted monetary valuation, using 16 methods. Only 9% did not quantify or discuss uncertainties associated with service quantification. The indicators and methods used to quantify the same type of ecosystem service varied. Only 3% of services used indicators of capacity, flow and demand in concert. Our results suggest indicators, data sources and methods for quantifying riverine ecosystem services should be more clearly defined and accurately represent the service they intend to quantify. Furthermore, more assessments of multiple services across diverse spatial extents and of riverine service interactions are needed, with better inclusion of stakeholders. Addressing these challenges will help riverine ecosystem service science inform river management. Synthesis and applications. The ecosystem service concept has great potential to inform riverine ecosystem management and decision‐making processes. However, this review of riverine ecosystem service quantification uncovers several remaining research gaps, impeding effective use of this tool to manage riverine ecosystems. We highlight these gaps and point to studies showcasing methods that can be used to address them.

An integrated ecological modeling system for assessing impacts of multiple stressors on stream and riverine ecosystem services within river basins

We demonstrate a novel, spatially explicit assessment of the current condition of aquatic ecosystem services, with limited sensitivity analysis for the atmospheric contaminant mercury. The Integrated Ecological Modeling System (IEMS) forecasts water quality and quantity, habitat suitability for aquatic biota, fish biomasses, population densities, productivities, and contamination by methylmercury across headwater watersheds. We applied this IEMS to the Coal River Basin (CRB), West Virginia (USA), an 8-digit hydrologic unit watershed, by simulating a network of 97 stream segments using the SWAT watershed model, a watershed mercury loading model, the WASP water quality model, the PiSCES fish community estimation model, a fish habitat suitability model, the BASS fish community and bioaccumulation model, and an ecoservices post-processer. Model application was facilitated by automated data retrieval and model setup and updated model wrappers and interfaces for data transfers between these models from a prior study. This companion study evaluates baseline predictions of ecoservices provided for 1990–2010 for the population of streams in the CRB and serves as a foundation for future model development.

Adaptive governance of riverine and wetland ecosystem goods and services

Adaptive governance and adaptive management have developed over the past quarter century in response to institutional and organizational failures, and unforeseen changes in natural resource dynamics. Adaptive governance provides a context for managing known and unknown consequences of prior management approaches and for increasing legitimacy in the implementation of flexible and adaptive management. Using examples from iconic water systems in the United States, we explore the proposition that adaptive management and adaptive governance are useful for evaluating the complexities of trade-offs among ecosystem goods and services.

The ecological benefit–loss evaluation in a riverine wetland for hydropower projects – A case study of Xiaolangdi reservoir in the Yellow River, China

This paper presents a comprehensive analysis on the ecological benefit and loss of Xiaolangdi reservoir from its completion in 2000 to 2012. We firstly propose a three-step framework of the ecological benefit–loss evaluation for hydropower projects, in accordance with which an index system of riverine wetland ecosystem services valuation was established originally. Then we make a quantitative valuation on the change of riverine wetland ecosystem services caused by this project. Finally, the ecological benefit and loss of the project in the riverine wetland were evaluated in two aspects of positive impacts and negative impacts. The results showed that (1) the positive impacts of Xiaolangdi reservoir mainly included 9 categories of ecosystem services: flood control, ice prevention, sedimentation reduction, energy substitution, emission reduction benefit, water supply, afforestation, shipping and entertainment; the total ecological benefit of the project in the riverine wetland was 26.2058billionyuan. (2) The negative impacts of Xiaolangdi reservoir mainly included 5 categories: loss due to land submergence, heritage submergence, water and soil erosion, reservoir sedimentation and immigration; the total ecological loss of the project in the riverine wetland was 24.2167billionyuan. (3) From 2000 to 2012, the net value of ecological benefit–loss for the project was 1.9891billionyuan.