Special Collection of Research on Rivers, River Species and River Conservation

 

Earth Science

 

1. Partington, D., Therrien, R., Simmons, C. T., & Brunner, P. (2017). Blueprint for a coupled model of sedimentology, hydrology, and hydrogeology in streambeds. Reviews of Geophysics, 55 (2), Pages 287–309.

Abstract: 

The streambed constitutes the physical interface between the surface and the subsurface of a stream. Across all spatial scales, surface water-groundwater interactions are controlled by the physical properties of the streambed. Streambed properties such as topography or hydraulic conductivity are continuously altered through erosion and sedimentation processes. Recent studies from the fields of ecology, hydrogeology and sedimentology provide field evidence that sedimentological processes themselves can be heavily influenced by surface water-groundwater interactions, giving rise to complex feedback mechanisms between sedimentology, hydrology and hydrogeology. More explicitly, surface water-groundwater exchanges play a significant role in the deposition of fine sediments, which in turn modify the hydraulic properties of the streambed. We explore these feedback mechanisms and critically review the extent of current interaction between the different disciplines. We identify opportunities to improve current modeling practices. For example, hydrogeological models treat the streambed as a static rather than a dynamic entity, while sedimentological models do not account for critical catchment processes such as surface water-groundwater exchange. A blueprint for a new modeling framework is proposed that bridges the conceptual gaps between sedimentology, hydrogeology and hydrology. Specifically, this blueprint.

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2. Huang, C., Chen, Y., Zhang, S., & Wu, J. (2018). Detecting, Extracting, and Monitoring Surface Water From Space Using Optical Sensors: A Review. Reviews of Geophysics, 56 (2), Pages 333–360.

Abstract: 

Observation of surface water is a functional requirement for studying ecological and hydrological processes. Recent advances in satellite-based optical remote sensors have promoted the field of sensing surface water to a new era. This paper reviews the current status of detecting, extracting, and monitoring surface water using optical remote sensing, especially progress in the last decade. It also discusses the current status and challenges in this field, including spatio-temporal scale issues, integration with in situ hydrological data and elevation data, obscuration caused by clouds and vegetation, and the growing need to map surface water at a global scale. Historically, sensors have exhibited a contradiction in resolutions. Techniques including pixel unmixing and reconstruction, and spatio-temporal fusion have been developed to alleviate this contradiction. Spatio-temporal dynamics of surface water have been modelled by combining remote sensing data with in situ river flow. Recent studies have also demonstrated that the river discharge can be estimated using only optical remote sensing imagery, providing valuable information for hydrological studies in ungauged areas. Another historical issue for optical sensors has been obscuration by clouds and vegetation. An effective approach of reducing this limitation is to combine with synthetic aperture radar data. Digital elevation model data have also been employed to eliminate cloud/terrain shadows. The development of big data and cloud computation techniques makes the increasing demand of monitoring global water dynamics at high resolutions easier to achieve. An integrated use of multisource data is the future direction for improved global and regional water monitoring.

 

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3. Hoshino, M., Watanabe, Y., & Kon, Y. (2017). Implication of Apatite and Anhydrite for Formation of an Iron-Oxide-Apatite ( IOA) Rare Earth Element Prospect, Benjamin River, Canada. Resource Geology, 67 (4), Pages 361–383.

Abstract: 

The Benjamin River apatite prospect in northern New Brunswick, Canada, is hosted by the Late Silurian Dickie Brook plutonic complex, which is made up of intrusive units represented by monzogranite, diorite and gabbro. The IOA ores, composed mainly of apatite, augite, and magnetite at Benjamin River form pegmatitic pods and lenses in the host igneous rocks, the largest of which is 100 m long and 10–20 m wide in the diorite and gabbro units. In this study, 28 IOA ore and rock samples were collected from the diorite and gabbro units. Mineralogical

observations show that the apatite–augite–magnetite ores are variable in the amounts of apatite, augite, and magnetite and are associated with minor amounts of epidote-group minerals (allanite, REE-rich epidote and epidte) and trace amounts of albite, titanite, ilmenite, titanomagnetite, pyrite, chlorite, calcite, and quartz. Apatite and augite grains contain small anhydrite inclusions. This suggests that the magma that crystallized apatite and augite had high oxygen fugacity. In back scattered electron (BSE) images, apatite grains in the ores have two zones of different appearance: (i) primary REE-rich zone; and (ii) porous REE-poor zone. The porous REE-poor zones mainly appear in rims and/or inside of the apatite grains, in addition to the presence of apatite grains which totally consist of a porous REE-poor apatite. This porous REE-poor apatite is characterized by low REE (<0.84 wt%), Si (<0.28 wt%), and Cl (<0.17 wt%) contents. Epidote-group minerals mainly occur in grain boundary between the porous REE-poor apatite and augite. These indicate that REE leached from primary REE-rich apatite crystallized as allanite and REE-rich epidote. Magnetite in the ores often occurs as veinlets that cut apatite grains or as anhedral grains that replace a part of augite. These textures suggest that magnetite crystallized in the late stage. Pyrite veins occur in the ores, including a large amount of quartz and calcite veins. Pyrite veins mainly occur with quartz veins in augite. These textures indicate pyrite veins are the latest phase. Apatite–augite–magnetite ore, gabbro–quartz diorite and feldspar dike collected from the Benjamin River prospect contain dirty pure albite (Ab98Or2–Ab100) under the microscope. The feldspar dikes mainly consist of dirty pure albite. Occurrences of the dirty pure albite suggest remarkable albitization (sodic alteration) of original plagioclase (An25.3–An60 in Pilote et al., 2012) associating with intrusion of monzogranite into gabbro and diorite. SO4 2_ bearing magma crystallized primary REE-rich apatite, augite and anhydrite reacted with Fe in the sodic fluids, which result in oxidation of Fe2+ and release of S2_ into the sodic fluids. REE, Ca and Fe from primary REE-rich apatite, augite and plagioclase altered by the sodic fluids were released into the fluids. Then Fe3+ in the sodic fluids precipitated as Fe oxides and epidote-group minerals in apatite–augite–magnetite ores. Finally, residual S2_ in sodic fluids crystallized as latest pyrite veins.

 

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4. Yamada, M., Fujino, S., Goff, J., & Chagué-Goff, C. (2016). Large-scale erosion and overbank deposition caused by the July 2013 flood of the Abu River, Yamaguchi City, Japan. Island Arc, 25 (5), Pages 386–399.

Abstract: 

This paper reports on the erosion, transport, and deposition processes associated with an overbank deposit formed by the flooding of the Abu River on July 28, 2013, in Yamaguchi City, Japan. At the study site, river flows overtopped the levee revetment upstream of a meander bend cutting it off and flowing back into the main channel downstream. In this sequential process, it deposited large amounts of sediments, ranging from mud to cobbles, on the floodplain. The surface of paddy fields adjacent to a railway line, located at the  center of the affected floodplain, was severely eroded by the flood flows. Overbank deposits composed of both upstream finer sediments and eroded coarser terrestrial sediments are laid down in the affected area. Large amounts of pebbles and cobbles originating from the eroded terrestrial area formed a gravelly pile on top of the sand and gravel sediments derived from the river. This finding indicates that sands and gravels were deposited prior to the formation of the gravelly pile, probably before and during peak flood flows. An inverse grading structure is evident in the lower to middle part of these comparatively thick deposits, most likely due to differences in transport pattern between entrained terrestrial gravels and upstream finer sediments.

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5. Stokes, M. F., Goldberg, S. L., & Perron, J. T. (2018). Ongoing River Capture in the Amazon. Geophysical Research Letters, 45 (11), Pages 5545–5552.

Abstract: 

River capture is thought to trigger abrupt changes in evolving continental drainage systems, but it is almost always inferred rather than observed, and the mechanisms that lead to capture are unclear. We shed light on these mechanisms by documenting an ongoing capture involving major South American rivers. The Rio Casiquiare is a distributary of the Rio Orinoco and a tributary of the Rio Negro; it forms a perennial water connection between the drainage basins of the Amazon and Orinoco, the largest and fourth-largest rivers on Earth by discharge. This unusual configuration is the result of an incomplete and ongoing river capture, in which the Rio Negro is capturing the upper Rio Orinoco. We describe a positive feedback between diversion of water into the capturing channel and sedimentation within the channel being captured, a mechanism that could drive river capture in the Amazon and elsewhere.

 

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Ecology

 

1. Payn, R. A., Hall, R. O., Kennedy, T. A., Poole, G. C., & Marshall, L. A. (2017). A coupled metabolic-hydraulic model and calibration scheme for estimating whole-river metabolism during dynamic flow conditions. Limnology and Oceanography: Methods, 15 (10), Pages 847–866.

Abstract: 

Conventional methods for estimating whole-stream metabolic rates from measured dissolved oxygen dynamics do not account for the variation in solute transport times created by dynamic flow conditions. Changes in flow at hourly time scales are common downstream of hydroelectric dams (i.e., hydropeaking), and hydrologic limitations of conventional metabolic models have resulted in a poor understanding of the controls on biological production in these highly managed river ecosystems. To overcome these limitations, we coupled a two-station metabolic model of dissolved oxygen dynamics with a hydrologic river routing model. We designed calibration and parameter estimation tools to infer values for hydrologic and metabolic parameters based on time series of water quality data, achieving the ultimate goal of estimating whole-river gross primary production and ecosystem respiration during dynamic flow conditions. Our case study data for model design and calibration were collected in the tailwater of Glen Canyon Dam (Arizona, U.S.A.), a large hydropower facility where the mean discharge was 325 m3 s21 and the average daily coefficient of variation of flow was 0.17 (i.e., the hydropeaking index averaged from 2006 to 2016). We demonstrate the coupled model’s conceptual consistency with conventional models during steady flow conditions, and illustrate the potential bias in metabolism estimates with conventional models during unsteady flow conditions. This effort contributes an approach to solute transport modeling and parameter estimation that allows study of whole-ecosystem metabolic regimes across a more diverse range of hydrologic conditions commonly encountered in streams and rivers.

 

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2. Benito, X., Fritz, S. C., Steinitz-Kannan, M., Tapia, P. M., Kelly, M. A., & Lowell, T. V. (2018). Geo-climatic factors drive diatom community distribution in tropical South American freshwaters. Journal of Ecology, 106 (4), Pages 1660–1672.

Abstract: 

1.  Patterns that maintain and generate biodiversity of macro-organisms in the Neotropics are widely discussed in the scientific literature, yet the spatial ecology of micro-organisms is largely unknown. The unique character of the tropical Andes and adjacent Amazon lowlands generates a wide gradient of environmental conditions to advance our understanding of what drives community assembly and diversity processes. 2. We analysed the distribution patterns of benthic diatoms (unicellular siliceous algae) as a model group of microbial passive dispersers, including predictors that describe limnological and geo-climatic gradients for a total of 113 waterbodies (0–28°S and 58–80°W), including lakes and streams. Complementary multivariate statistical analyses were performed to correlate (1) community composition and (2) diatom species richness with environmental and spatial factors to infer niche-based and dispersal-based assembly processes, respectively. 3. Results showed that two gradients structured both diatom assemblages and waterbodies, namely climate and landscape configuration. Variance partitioning revealed that broadscale spatial variables (distance-based Moran’s Eigenvectors) outperformed the two environmental components (limnological and geo-climatic), suggesting dispersal-assembled communities. However, diatom assemblages were structured by geo-climatic (regional) factors in certain lakes in the northern and central Andes, although their effects were partially manifested via local variables after the geographical distances were factored out. In a similar way, climatic and topographic structuring homogenized lake and stream communities within ecoregions, as indicated by the strong overlap between the two community types and the weak correlation between biota and limnological variables. Notably, a significant increase in diatom species richness was related to increased water connectivity, interpreted to indicate that a decrease in the remoteness of the system increase species number. 4. Synthesis. We emphasize the strength of macroecological gradients (landscape configuration and climatic factors) in affecting both diatom diversity and community composition in the South American tropics. In this context, our results and the commonalities of ecoregion patterning with groups of macro-organisms (vegetation) suggest the need to integrate microbial ecology into a macroecology framework to unravel mechanisms behind diversity gradients.

 

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3. West, A. O., & Scott, J. T. (2016). Black disk visibility, turbidity, and total suspended solids in rivers: A comparative evaluation. Limnology and Oceanography: Methods, 14 (10), Pages 658–667.

Abstract: 

This study compared horizontal black disk visibility (BDV), a measure of visual water clarity, to turbidity and total suspended solids (TSS) concentrations in five rivers of the southwestern Ozarks of Arkansas, U.S. to assess its usefulness in evaluating optical water quality. We investigated correlative relationships between BDV vs. turbidity and BDV vs. TSS, and compared them to those reported in similar studies. Our results indicated that replicate measures of horizontal BDV were subject to less error than replicate turbidity (coefficients of variation were 5.0% and 6.4%, respectively), and BDV was more strongly correlated with TSS concentrations than was turbidity (correlations coefficients were 20.97 and 0.92, respectively). We also assessed the validity of the black disk method as a surrogate for TSS concentrations and derived a predictive model for each river in the study. The benefits of the horizontal black disk method are both scientific and practical. Horizontal BDV provides a means of quantifying the beam attenuation coefficient. And, the low cost, ease of use, and usefulness in shallow rivers make the black disk method a versatile tool in water quality assessment. We ultimately conclude that the horizontal black disk method should be added to routine monitoring programs in the U.S., and that it be adopted by public groups involved in volunteer monitoring and water quality communication that may be limited by equipment availability or budget.

 

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4. Cattarino, L., Hermoso, V., Carwardine, J., Adams, V. M., Kennard, M. J., & Linke, S. (2018). Information uncertainty influences conservation outcomes when prioritizing multi-action management efforts. Journal of Applied Ecology, 55 (5), Pages 2171–2180.

Abstract: 

1. In managing various threats to biodiversity, it is important to prioritize multiple management actions and the levels of effort to apply. However, a spatial conservation prioritization framework that integrates these key aspects, and can be generalized, is still missing. Moreover, assessing the robustness of prioritization frameworks to uncertainty in species responses to management is critical to avoid misallocation of limited resources. Yet, the impact of information uncertainty on prioritization of management effort remains unknown.

2. We present an approach for prioritizing alternative levels of conservation management effort to multiple actions, based on the ecological responses of species to management. We estimated species responses through a structured email based expert elicitation process, where we also captured the uncertainty in individual experts’ assessments. We identified priority locations and associated level of management of effort of four actions to abate threats to freshwater-dependent fauna, using a northern Australia case study, and quantified sensitivity of the proposed solution to uncertainty in the answers of each individual expert.

3. Achievement of conservation targets for freshwater-dependent fauna in the Daly River catchment would require 9.4 million AU$ per year, for a total of approximately 189 million AU$ investment over 20 years. We suggest that this could be best achieved through a mix of aerial shooting of buffalos and pigs, riparian fencing and chemical spraying of weeds, applied at varying levels of management effort in key areas of the catchment.

4. Uncertainty in experts’ estimation of species responses to threats causes 60% of the species to achieve 80% of their conservation targets, which was consistent across target levels.

5. Synthesis and applications. Our prioritization approach facilitates the planning of conservation management at fine spatial scales and is applicable to terrestrial, freshwater and marine realms. Plan implementation may require policy instruments ranging from landowner stewardship agreements, market-based mechanisms and low-intensity land use management schemes, to regulation of commercial activities within portions of marine protected areas. However, assessing plan sensitivity to uncertainty in species response to management and finding ways of dealing with it in the prioritization rather than ignoring it, as often done, remains vital for effective achievement of conservation objectives.

 

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5. De Jager, M., Kaphingst, B., Janse, E. L., Buisman, R., Rinzema, S. G. T., & Soons, M. B. (2018). Seed size regulates plant dispersal distances in flowing water. Journal of Ecology.

Abstract: 

1. Dispersal is an essential component of plant life, especially under the current threats of anthropogenic habitat fragmentation and climate change. For many wetland species, water is a key dispersal vector, as it can presumably disperse seeds long distances and towards suitable sites for establishment. Seed dispersal distance is affected by stream characteristics and seed traits. Yet, the effect of relevant seed traits, such as size, remains largely unknown.

2. Here, we report on an experimental field study examining the effect of seed size on dispersal distance in lowland streams. We released cork seed mimics of different sizes in four Dutch lowland streams in restored and channelized sections. After 24 hr, we recorded their entrapment location, entrapment mechanism, and the vegetation type in which they were caught.

3. Large seeds generally dispersed over longer distances than smaller seeds. This effect of seed size is likely caused by the different entrapment mechanisms—net trapping, surface tension, and wake trapping—which were highly correlated with seed size. Especially net trapping was responsible for the capture of a large proportion of small seed mimics in vegetation such as aquatic and riparian grasses, starwort, and reed. Due to the prevalent occurrence of these vegetation types in lowland streams, particularly during summer, smaller seeds are more likely to become entrapped and, hence, disperse less far. Our analysis on existing seed data reveals that water‐dispersed riparian plants have relatively large seeds and are thereby evolutionarily adapted to long‐distance dispersal. Furthermore, our results indicate that median dispersal distances are 0.02–1.8 km (99‐percentile <8.5 km) in lowland streams in summer. In winter, less vegetation is present in and surrounding the streams, which leads to median dispersal distances of 0.12– 14.2 km (99‐percentile <65 km).

4. Synthesis. This study demonstrates that (a) large seeds generally disperse further than smaller seeds in lowland steams and (b) distances depend strongly on stream vegetation. This information should inform future restoration, for instance, by planning efforts to coincide with times or conditions of open water which are more favourable for the dispersal of target plant species—especially those with small seeds (<10 mm).

 

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6. Erős, T., O’Hanley, J. R., & Czeglédi, I. (2018). A unified model for optimizing riverscape conservation. Journal of Applied Ecology, 55 (4), Pages 1871–1883.

Abstract:

1. Spatial prioritization tools provide a means of finding efficient trade-offs between biodiversity protection and the delivery of ecosystem services. Although a large number of prioritization approaches have been proposed in the literature, most are specifically designed for terrestrial systems. When applied to river ecosystems, they often fail to adequately account for the essential role that landscape connectivity plays in maintaining both biodiversity and ecosystem services. This is particularly true of longitudinal connectivity, which in many river catchments is highly altered by the presence of dams, stream-road crossings, and other artificial structures.

2. We propose a novel framework for coordinating river conservation and connectivity restoration. As part of this, we formulate an optimization model for deciding which sub catchments to designate for ecosystem services and which to include in a river protected area (RPA) network, while also deciding which existing river barriers to remove in order to maximize longitudinal connectivity within the RPA network. In addition to constraints on the size and makeup of the RPA network, the model also considers the suitability of sites for conservation, based on a biological integrity index, and connectivity to multiple habitat types. We demonstrate the usefulness of our approach using a case study involving four managed river catchments located in Hungary.

3. Results show that large increases in connectivity-weighted habitat can be achieved through targeted selection of barrier removals and that the benefits of barrier removal are strongly depend on RPA network size. We find that (i) highly suboptimal solutions are produced if habitat conservation planning and connectivity restoration are done separately and (ii) RPA acquisition provides substantially greater marginal benefits than barrier removal given limited resources.

4. Synthesis and applications. Finding a balance between conservation and ecosystem services provision should give more consideration to connectivity restoration planning, especially in multi-use rivers capes. We resent the first modelling framework to directly integrate and optimize river conservation and connectivity restoration planning. This framework can help conservation managers to account better for connectivity, resulting in more effective catchment scale maintenance of biological integrity and ecosystem services delivery.

 

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7. Kennen, J. G., Stein, E. D., & Webb, J. A. (2018). Evaluating and managing environmental water regimes in a water-scarce and uncertain future. Freshwater Biology, 63 (8), Pages 733–737.

Abstract:

1. While the number of environmental flows and water science programmes continues to grow across the globe, there remains a critical need to better balance water availability in support of human and ecological needs and to recognise the environment as a legitimate user of water. In water-stressed areas, this recognition has resulted in friction between water users in the public and private sectors. An opportunity exists for practitioners to be on the forefront of the science determining best practices for supporting environmental water regimes.

2. This Special Issue brings together a collection of environmental flows science and water management papers organised around three major themes: (1) method development and testing; (2) application case studies; and (3) efficacy evaluation. Contents of this Special Issue are intended to foster collaboration and broaden transferability of the information, technical tools, models and methods needed to support environmental water management programmes.

3. The technical sophistication of methods and modelling tools, while important to the advancement of environmental water science, may come at the expense of easily interpretable outcomes that positively influence management decisions. Researchers need to be more proactive in translating the results of advanced modelling methodologies into user-friendly tools and methods. This will allow stakeholders and water managers to proactively test alternative water allocation scenarios to help address growing human water demands in the face of droughts and changes in climatic patterns.

4. The application of environmental flows science and water management strategies cannot be done in isolation. Implementation involves a complex decision-making process that integrates ecological, hydrologic and social science across diverse multifaceted governance systems and requires active stakeholder involvement. Scientists and managers must strengthen partnerships at multiple scales to develop sensible science investment strategies so that collective knowledge can be translated into wise environmental water management decisions.

 

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8. Sergeant, C. J., Bellmore, J. R., McConnell, C., & Moore, J. W. (2017). High salmon density and low discharge create periodic hypoxia in coastal rivers. Ecosphere, 8 (6), e01846.

Abstract:

Dissolved oxygen (DO) is essential to the survival of almost all aquatic organisms. Here, we examine the possibility that abundant Pacific salmon (Oncorhynchus spp.) and low streamflow combine to create hypoxic events in coastal rivers. Using high-frequency DO time series from two similar watersheds in southeastern Alaska, we summarize DO regimes and the frequency of hypoxia in relationship to salmon density and stream discharge. We also employ a simulation model that links salmon oxygen respiration to DO dynamics and predicts combinations of salmon abundance, discharge, and water temperature that may result in hypoxia. In the Indian River, where DO was monitored hourly during the ice-free season from 2010 to 2015, DO levels decreased when salmon were present. In 2013, a year with extremely high spawning salmon densities, DO dropped to 1.7 mg/L and 16% saturation, well below lethal limits. In Sawmill Creek, where DO was monitored every six minutes across an upstream–downstream gradient during the 2015 spawning season, DO remained fully saturated upstream of spawning reaches, but declined markedly downstream to 2.9 mg/L and 26% saturation during spawning. Modeled DO dynamics in the Indian River closely tracked field observations. Model sensitivity analysis illustrates that low summertime river discharge is a precursor to salmon-induced oxygen depletion in our study systems. Our results provide compelling evidence that dense salmon populations and low discharge can trigger hypoxia, even in rivers with relatively cold thermal regimes. Although climate change modeling for southeastern Alaska predicts an increase in annual precipitation, snowfall in the winter and rainfall in the summer are likely to decrease, which would in turn decrease summertime discharge in rain- and snow-fed streams and potentially increase the frequency of hypoxia. Our model template can be adapted by resource managers and watershed stakeholders to create real-time predictive models of DO trends for individual streams. While preserving thermally suitable stream habitat for cold-water taxa facing climate change has become a land management priority, managers should also consider that some protected watersheds may still be at risk of increasingly frequent hypoxia due to human impacts such as water diversion and artificially abundant salmon populations caused by hatchery straying.

 

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9. Ritz, S., Eßer, M., Arndt, H., & Weitere, M. (2017). Large-scale patterns of biofilm-dwelling ciliate communities in a river network: Only small effects of stream order. International Review of Hydrobiology, 102 (5-6), Pages 114–124.

Abstract:

Although biofilm-dwelling microfauna (i.e., small metazoans and protzoans) can play an important role in the flux of matter in running waters, their dynamics, and control within stream networks are as yet poorly understood. Here, we analyzed the longitudinal (from first order stream to large river) dynamics of ciliates associated to hard substrate within a river network. Both ciliate abundance and their taxonomical community structure showed no correlations to stream order, although the community structure of the largest river, the Rhine, differed from those of the other rivers. The abundances of biofilm-dwelling bacteria, algae, rotifers, and nematodes also showed no correlation with stream order. The above results contrast to the abundances of planktonic algae and bacteria that were significantly and positively correlated with the stream order. The results showed that stream size and the corresponding planktonic resource concentration are not reliable parameters in predicting the abundances and community structures of biofilm-dwelling ciliates. In fact, local parameters seemed to have stronger effects on benthic microfauna communities. Thus, the impact of small-scale habitat patterns needs further attention in explaining the community structure of biofilm-dwelling ciliates.

 

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10. Zampatti, B. P., Leigh, S. J., Bice, C. M., & Rogers, P. J. (2018). Multiscale movements of golden perch (Percichthyidae: Macquaria ambigua ) in the River Murray, Australia. Austral Ecology.

Abstract:

Understanding the spatio-temporal characteristics of animal movement is integral to effective conservation and management. Golden perch (Macquaria ambigua) is a potamodromous species known to undertake long-distance movements, putatively in response to elevated flow in spring and summer. In this study, 52 adult golden perch from the lower River Murray were surgically implanted with radio transmitters and passive integrated transponder (PIT) tags, and tracked for 2 years. Strong site fidelity was common, with 19 fish (~36%) remaining at the site of capture throughout the study. This included a spawning season (spring-summer) and a period of elevated flow. Eighteen fish (35%) made small- to medium-scale (2–22 km) movements that included the establishment of new home sites. Fifteen fish (29%) migrated long distances (33–270 km) upstream in spring–summer, coincident with steady, falling and rising flows. These movements were correlated with seasonal variation in mean daily water temperature, and to a lesser extent, short-term (10-day) flow variability, and did not coincide with spawning or recruitment during the year of migration. This contrasts previous studies that have associated long-distance movements of golden perch with increased flows and spawning. Upstream migration continued until passage was blocked by a weir, or fish were captured by anglers. Our results highlight the need for a broad spatio-temporal perspective when investigating the movement of long-lived potamodromous fishes, to integrate the range of behaviours exhibited by individuals and population contingents. We advocate that life history models that incorporate behavioural plasticity and a river-scale perspective will advance conservation.

 

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11. Naman, S. M., Rosenfeld, J. S., Kiffney, P. M., & Richardson, J. S. (2018). The energetic consequences of habitat structure for forest stream salmonids. Journal of Animal Ecology, 87 (5), Pages 1383–1394.

Abstract:

1. Increasing habitat availability (i.e. habitat suitable for occupancy) is often assumed to elevate the abundance or production of mobile consumers; however, this relationship is often nonlinear (threshold or unimodal). Identifying the mechanisms underlying these nonlinearities is essential for predicting the ecological impacts of habitat change, yet the functional forms and ultimate causation of consumer-habitat relationships are often poorly understood.

2. Nonlinear effects of habitat on animal abundance may manifest through physical constraints on foraging that restrict consumers from accessing their resources. Subsequent spatial incongruence between consumers and resources should lead to unimodal or saturating effects of habitat availability on consumer production if increasing the area of habitat suitable for consumer occupancy comes at the expense of habitats that generate resources. However, the shape of this relationship could be sensitive to cross-ecosystem prey subsidies, which may be unrelated to recipient habitat structure and result in more linear habitat effects on consumer production.

3. We investigated habitat-production relationships for juveniles of stream-rearing Pacific salmon and trout (Oncorhynchus spp.), which typically forage in low-velocity pool habitats, while their prey (drifting benthic invertebrates) are produced upstream in high-velocity riffles. However, juvenile salmonids also consume subsidies of terrestrial invertebrates that may be independent of pool-riffle structure.

4. We measured salmonid biomass production in 13 experimental enclosures each containing a downstream pool and upstream riffle, spanning a gradient of relative pool area (14%–80% pool). Increasing pool relative to riffle habitat area decreased prey abundance, leading to a nonlinear saturating effect on fish production. We then used bioenergetics model simulations to examine how the relationship between pool area and salmonid biomass is affected by varying levels of terrestrial subsidy. Simulations indicated that increasing terrestrial prey inputs linearized the effect of habitat availability on salmonid biomass, while decreasing terrestrial inputs exaggerated a “hump-shaped” effect.

5. Our results imply that nonlinear effects of habitat availability on consumer production can arise from trade-offs between habitat suitable for consumer occupancy and habitat that generates prey. However, cross-ecosystem prey subsidies can effectively decouple this trade-off and modify consumer-habitat relationships in recipient systems.

 

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12. Radinger, J., Essl, F., Hölker, F., Horký, P., Slavík, O., & Wolter, C. (2017). The future distribution of river fish: The complex interplay of climate and land use changes, species dispersal and movement barriers. Global Change Biology, 23 (11), Pages 4970–4986.

Abstract:

The future distribution of river fishes will be jointly affected by climate and land use changes forcing species to move in space. However, little is known whether fish species will be able to keep pace with predicted climate and land use-driven habitat shifts, in particular in fragmented river networks. In this study, we coupled species distribution models (stepwise boosted regression trees) of 17 fish species with species-specific models of their dispersal (fish dispersal model FIDIMO) in the European River Elbe catchment. We quantified (i) the extent and direction (up- vs. downstream) of predicted habitat shifts under coupled “moderate” and “severe” climate and land use change scenarios for 2050, and (ii) the dispersal abilities of fishes to track predicted habitat shifts while explicitly considering movement barriers (e.g., weirs, dams). Our results revealed median net losses of suitable habitats of 24 and 94 river kilometers per species for the moderate and severe future scenarios, respectively. Predicted habitat gains and losses and the direction of habitat shifts were highly variable among species. Habitat gains were negatively related to fish body size, i.e., suitable habitats were projected to expand for smaller-bodied fishes and to contract for larger-bodied fishes. Moreover, habitats of lowland fish species were predicted to shift downstream, whereas those of headwater species showed upstream shifts. The dispersal model indicated that suitable habitats are likely to shift faster than species might disperse. In particular, smaller-bodied fish (<200 mm) seem most vulnerable and least able to track future environmental change as their habitat shifted most and they are typically weaker dispersers. Furthermore, fishes and particularly larger-bodied species might substantially be restricted by movement barriers to respond to predicted climate and land use changes, while smaller-bodied species are rather restricted by their specific dispersal ability.

 

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13. Kyne, P. M., & Feutry, P. (2017). Recreational fishing impacts on threatened river sharks: A potential conservation issue. Ecological Management & Restoration, 18 (3), Pages 209–213.

Abstract:

The Adelaide River in Australia’s Northern Territory is a popular recreational fishing area, as well as habitat for threatened and protected river sharks (Glyphis species). Both the Critically Endangered Speartooth Shark (Glyphis glyphis) and Endangered Northern River Shark (Glyphis garricki) are identified here in illegal catches from recreational angling. The identification of a decayed shark specimen using a DNA barcoding-like approach is the first such application to the identification of protected sharks in a recreational fishery. While the extent of catches by recreational anglers is unknown, the threatened status of these sharks, their suspected low population sizes, restricted distributions and importance of the Adelaide River as a nursery area call for the consideration of this as a potential conservation issue. As such, appropriate measures should be taken to reduce interactions with recreational anglers. The primary target species in the river is the iconic sportfish, Barramundi, which is predominantly caught by unbaited lure. Sharks are rarely caught on lure, allowing an opportunity for mitigation to focus on a fishing activity (baited hooks) which would limit any regulatory impact on popular lure fishing. Potential mitigation measures range from increased angler education and compliance checks, to the implementation of a spatial closure to baited hook fishing (a lure-only zone). Such measures may assist in meeting a stated objective of the Australian Government’s river shark Recovery Plan to ‘reduce and, where possible, eliminate adverse impacts of recreational fishing’.

 

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14.  Kaus, A., Büttner, O., Schäffer, M., Balbar, G., Surenkhorloo, P., & Borchardt, D. (2016). Seasonal home range shifts of the Siberian taimen (Hucho taimenPallas 1773): Evidence from passive acoustic telemetry in the Onon River and Balj tributary (Amur River basin, Mongolia). International Review of Hydrobiology, 101 (5-6), Pages 147–159.

Abstract:

Hucho taimen, the world’s largest salmonid, is a potadromous species that is listed as endangered in Mongolia. While mature individuals are known to have extended longitudinal movements of over 90km along main river channels, details of the seasonal movements and residency of individuals within and between tributary habitats have been largely undocumented. Therefore, the current research aimed to detect and quantify the seasonal distances moved by adult taimen (65–96 cm; n¼10) within and between the Onon River (Amur River basin) and a major tributary (Balj) over 12 months using passive acoustic telemetry. The median distance moved by taimen in spring was 17.4km (n¼6), in summer 9.1km (n¼4), autumn 4.7km (n¼9) and winter 0.4km (n¼8). However, there were no statically significant differences amongst these median seasonal home range sizes. Two taimen traversed between the Onon River and the Balj tributary during the study period, recording overall home ranges of 44.5km and 126.1 km. One of these individuals moved twice, exiting the tributary in autumn and returning again in spring where it remained for 36 days, while the second taimen moved only once into the tributary in spring and re-entered the main channel in late summer after 85 days. Another two taimen entered surrounding smaller tributaries and recorded home ranges of 26.1km and 29.2 km, while all remaining individuals were detected moving only within the waterway where they were originally captured and released (0.8–20.1 km). Taimen movements within tributaries such as the Balj can be extensive (<60 km), as they provide access to important spawning, feeding and overwintering habitats as well as refuge from adverse thermal and hydrological conditions. Thus to enhance population recovery, it is essential that current and future management and conservation efforts include preserving or restoring the ecological integrity and hydrological connectivity of these critical tributaries and the main river channel throughout the Onon and Amur River basins and across the remaining distribution of this endangered species.

 

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15. Sengupta, A., Adams, S. K., Bledsoe, B. P., Stein, E. D., McCune, K. S., & Mazor, R. D. (2018). Tools for managing hydrologic alteration on a regional scale: Estimating changes in flow characteristics at ungauged sites. Freshwater Biology, 63 (8), Pages 769–785.

Abstract:

1. Hydrologic alteration is a predominant stressor for biological resources in streams. This stress is further aggravated by competing human and ecological demands for limited water resources. Understanding flow–ecology relationships and establishing relevant and implementable flow targets are essential to protect biological communities.

2. Estimating degree of ecologically relevant hydrologic alteration depends on the availability of long-term flow data at sites with biological information. However, measured flow data are seldom available at sufficient density to support largescale analyses of the biological effects of hydrologic alterations. The ability to accurately simulate flows and estimate flow metrics at many ungauged locations across a broad geographical area remains a fundamental challenge.

3. We address this challenge by applying a novel technique to simulate flow regimes at any stream reach of interest by first developing an ensemble of regionally calibrated and validated hydrological models, and then using a selection tool to match the “best-fit” model to ungauged stream reaches. An ensemble of 26 HEC-HMS rainfall–runoff models were calibrated to represent the range of catchment conditions in the southern California region.

4. We developed current and historical flow regimes and a suite of flow metrics at 572 ungauged sites in southern California with bioassessment monitoring data. The flow metrics represent hydrograph characteristics of magnitude, timing, frequency, duration and variability. The flow metrics were estimated under three precipitation conditions—dry, wet and average. In addition, we estimated aggregated flow metrics for (dry + wet + average) condition. Hydrologic alteration was estimated as the deviation between the modelled current and historical flow metrics.

5. Approximately 79% of the region shows some degree of hydrologic alteration, and approximately 40% of the sites are estimated to be severely altered. Magnitude metrics tend to increase in response to urban and agricultural land uses, whereas the timing and duration metrics are mostly unchanged.

6. This mechanistic modelling approach demonstrates the feasibility of estimating flow alterations for ungauged catchments with relative ease of transferability over a broad geographical region. The continuous granular flow data allow for computation and consideration of metrics that may be applicable to a variety of ecological endpoints and consideration of a range of management trade-offs.

 

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16. Grant, J. W. A., Weir, L. K., & Steingrímsson, S. Ó. (2017). Territory size decreases minimally with increasing food abundance in stream salmonids: Implications for population regulation. Journal of Animal Ecology, 86 (6), Pages 1308–1316.

Abstract:

1. How the local density of territorial animals responds to changes in food abundance will depend on the flexibility of territory size. Quantitative estimates of territory size over a broad range of food abundance are relatively rare because of the difficulty of measuring food abundance in the wild.

2. Stream salmonids are an ideal model system for investigating flexibility in territory size, because food abundance can be quantified in the field and manipulated in the laboratory. We conducted a meta-analysis to test whether territory size decreases with increasing food abundance, and a mixed model analysis to test among three competing predictions: with increasing food abundance, territory size will be (1) fixed—the slope of a regression of log territory size vs. log food abundance = 0; (2) flexible and decreasing, as if individuals are defending a fixed amount of food—a slope = −1; and (3) initially compressible, but with an asymptotic minimum size—a slope between 0 and −1.

3. We collected data from 16 studies that manipulated or measured food abundance while monitoring changes in territory size of young-of-the-year salmonids; 10 were experimental laboratory studies, whereas six were observational field studies.

4. Overall, territory size decreased significantly with increasing food abundance; the weighted average correlation coefficient was −0.31. However, the estimated slope of the relationship between log territory size and log food abundance was only −0.23, significantly different from 0, and also significantly shallower than −1.

5. Our estimated slope suggests that attempts to increase the density of territorial salmonids by increasing food abundance and reducing territory size will be inefficient; a 20-fold increase in food abundance would be required to double population density. Our analysis may also have implications for other species with a territorial mosaic social system—i.e. contiguous territories. In these social systems, social Inertia will dampen any effects of changes in food abundance on the local density of settlers, compared to non-territorial species or those with non-contiguous territories.

 

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17. Ward, N. D., Sawakuchi, H. O., Neu, V., Less, D. F. S., Valerio, A. M., Cunha, A. C., … Keil, R. G. (2018). Velocity-amplified microbial respiration rates in the lower Amazon River. Limnology and Oceanography Letters, 3 (3), Pages 265–274.

Abstract:

Most measurements of respiration rates in large tropical rivers do not account for the influence of river flow conditions on microbial activity. We developed a ship-board spinning incubation system for measuring O2 drawdown under different rotation velocities and deployed the system along the lower Amazon River during four hydrologic periods. Average respiration rates in incubation chambers rotated at 0.22 m s21 and 0.66 m s21 were 1.4 and 2.4 times higher than stationary chambers, respectively. On average, depth-integrated.

 

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18. Gilbert, M. J. H., & Tierney, K. B. (2017). Warm northern river temperatures increase post-exercise fatigue in an Arctic migratory salmonid but not in a temperate relative. Functional Ecology, 32 (3), Pages 687–700.

Abstract:

1. The Arctic is warming at twice the global average rate; how native and non-native anadromous fishes will respond remains largely unknown. Some native Arctic salmonids are already experiencing warm (>21°C), physically challenging migratory river conditions and large diurnal temperature fluctuations (>10°C).

2. We conducted field and laboratory experiments to determine how these extreme conditions may affect the capacity for migration in Arctic and temperate salmonids.

3. In adult migratory Arctic char, reflex impairment following a handling challenge increased with temperature, indicating more extensive fatigue. In Arctic char smolts, temperature did not affect initial critical swimming performance (Umax1), however, there was a threshold for repeat swimming performance (Umax2) near 20°C, above which recovery was impaired.

4. Following a simulated diurnal warming scenario (11–21°C), Umax1 increased in rainbow trout and remained constant in Arctic char as in the field while Umax2 remained constant in rainbow trout it was drastically reduced in Arctic char. Furthermore, at warm temperatures, Arctic char were unable to recover to routine levels of oxygen uptake after exercise, while rainbow trout were. Warming also had more pronounced effects on blood composition and plasma glucose and lactate concentration in Arctic char than in rainbow trout.

5. In general, rainbow trout, a temperate salmonid, had superior swimming performance, aerobic capacity, and warm tolerance than Arctic char, an Arctic salmonid.

6. The present flow and temperature regimes in some Arctic rivers may restrict migration of native salmonids by limiting their ability to recover from fatiguing exercise. Non-native, temperate salmonids are likely better suited to overcome these particular physical and thermal challenges.

 

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19. Whitlock, R., Mäntyniemi, S., Palm, S., Koljonen, M.-L., Dannewitz, J., & Östergren, J. (2018). Integrating genetic analysis of mixed populations with a spatially explicit population dynamics model. Methods in Ecology and Evolution, 9 (4), Pages 1017–1035.

Abstract:

1. Inferring the dynamics of populations in time and space is a central challenge in ecology. Intra-specific structure (for example genetically distinct sub-populations or metapopulations) may require methods that can jointly infer the dynamics of multiple populations. This is of particular importance for harvested species, for which management must balance utilization of productive populations with protection of weak ones.

2. Here we present a novel method for simultaneous learning about the spatio-temporal dynamics of multiple populations that combines genetic data with prior information about abundance and movement, akin to an integrated population modelling approach. We apply the Bayesian genetic mixed stock analysis to 17 wild and 10 hatchery-reared Baltic salmon (S. salar) stocks, quantifying uncertainty in stock composition in time and space, and in population dynamics parameters such as migration timing and speed.

3. The genetic data were informative about stock-specific movement patterns, updating priors for migration path, timing and speed. Use of a population dynamics model allowed robust interpolation of expected catch composition at areas and times with no genetic observations. Our results indicate that the commonly used “equal prior probabilities” assumption may not be appropriate for all mixed stock analyses: incorporation of prior information about stock abundance and movement resulted in more plausible and precise estimates of mixture compositions in time and space.

4. The model we present here forms the basis for optimizing the spatial and temporal allocation of harvest to support the management of mixed populations of migratory species.

 

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Environmental Science

 

1. Dahake, S. (2018). Taming Godavari River: Navigating through religious, developmental, and environmental narratives. Wiley Interdisciplinary Reviews: Water, 5 (5), e1297.

Abstract:

Exploring the production and the social construction of Godavari riverscape in Nashik, this article presents a case of ongoing socio-ecological transformations in the Indian cities. This case-study aims to contribute to the burgeoning scholarship on the political ecology of urban water bodies in India and expands the political ecology of waterscapes by engaging with the cultural politics of water. The Godavari, one of the seven sacred rivers in Hinduism, meanders through the fast urbanizing and a religious city of Nashik. Thousands of pilgrims converge every day along the Godavari in the Nashik and millions throng during the Hindu pilgrimage festival of Kumbh Mela—one of the biggest congregations in the world. Here, religious tourism coupled with modernist developmental agendas is rapidly (re)shaping the river into a prized religious and real estate commodity while ignoring the river ecology. This article nuances the perception, investigation, and management of rivers by examining three interrelated questions: How do the performance, circulation, and contestation of the multiple narratives surrounding the river transform its ecology and relationship with the city? In what ways do notions of control and exploitation of rivers normalize in the collective conscience of the societies? How do social relations (re)create and configure the emotional ties with the river in public imagination? This article is categorized under:

Human Water > Water as Imagined and Represented

Water and Life > Conservation, Management, and Awareness

 

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2. Smith, D. R., Butler, R. S., Jones, J. W., Gatenby, C. M., Hylton, R. E., Parkin, M. J., & Schulz, C. A. (2017). Developing a landscape-scale, multi-species, and cost-efficient conservation strategy for imperilled aquatic species in the Upper Tennessee River Basin, USA. Aquatic Conservation: Marine and Freshwater Ecosystems, 27 (6), Pages 1224–1239.

Abstract:

1. Strategic conservation of imperilled species faces several major challenges including uncertainty in species response to management actions, budgetary constraints that limit options, and the need to scale expected conservation benefits from local to landscape levels and from single to multiple species.

2. A structured decision‐making process was applied to address these challenges and identify a cost‐effective conservation strategy for the Federally listed endangered and threatened aquatic species in the Upper Tennessee River Basin (UTRB). The UTRB, which encompasses a landscape of ~58 000 km2, primarily in western North Carolina, eastern Tennessee, and south‐western Virginia, harbours one of the most globally diverse assemblages of freshwater fishes and mussels at temperate latitudes. To develop a strategy for conservation of 12 fish species and 24 mussel species over a 20‐year period, a management strategy that would best recover these species was identified given costs and uncertainty in management effectiveness.

3. The main insights came from a trade‐off analysis that compared alternative allocations of effort among management actions. A strategy emphasizing population management, which included propagation and translocation, performed best across a wide range of objective weightings and was robust to uncertainty in management effectiveness. Species prioritization was based on the expected conservation benefit from the best performing strategy, degree of imperilment, and species‐specific management costs. Sub‐basin prioritization was based on expected conservation benefit from the best performing strategy and feasibility of habitat management and threat abatement.

4. Although the strategy was developed for imperilled aquatic species in the UTRB, the structured process is applicable for developing cost‐efficient strategies to conserve multiple species across a landscape under uncertain management effectiveness. The process can assist a manager with limited resources to understand which species to work on, where to conduct that work.

 

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3. Doorn, N. (2016). Allocating responsibility for environmental risks: A comparative analysis of examples from water governance. Integrated Environmental Assessment and Management, 13 (2), Pages 371–375.

Abstract:

The focus of the present study is on the allocation of responsibilities for addressing environmental risks in transboundary water governance. Effective environmental management in transboundary situations requires coordinated and cooperative action among diverse individuals and organizations. Currently, little insight exists on how to foster collective action such that individuals and organizations take the responsibility to address transboundary environmental risks. On the basis of 4 cases of transboundary water governance, it will be shown how certain allocation principles are more likely to encourage cooperative action. The main lesson from these case studies is that the allocation of responsibilities should be seen as a risk distribution problem, including considerations of effectiveness, efficiency, and fairness.

 

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4. Collier, K. J. (2017). Editorial: Measuring river restoration success: Are we missing the boat? Aquatic Conservation: Marine and Freshwater Ecosystems, 27 (3), Pages 572–577.

 

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5. Elliott, S. M., Brigham, M. E., Kiesling, R. L., Schoenfuss, H. L., & Jorgenson, Z. G. (2018). Environmentally relevant chemical mixtures of concern in waters of United States tributaries to the Great Lakes. Integrated Environmental Assessment and Management, 14 (4), Pages 509–518.

Abstract:

The North American Great Lakes are a vital natural resource that provide fish and wildlife habitat, as well as drinking water and waste assimilation services for millions of people. Tributaries to the Great Lakes receive chemical inputs from various point and non-point sources, and thus are expected to have complex mixtures of chemicals. However, our understanding of the co-occurrence of specific chemicals in complex mixtures is limited. To better understand the occurrence of specific chemical mixtures in the U.S. Great Lakes basin, surface water from 24 U.S. tributaries to the Laurentian Great Lakes was collected and analyzed for diverse suites of organic chemicals, primarily focused on chemicals of concern (e.g. pharmaceuticals, personal care products, fragrances, etc.). A total of 181 samples and 21 chemical classes were assessed for mixture compositions. Basin wide, 1,664 mixtures occurred in at least 25% of sites. The most complex mixtures identified were comprised of nine chemical classes and occurred in 58% of sampled tributaries. Pharmaceuticals typically occurred in complex mixtures, reflecting pharmaceutical-use patterns and wastewater facility outfall influences. Fewer mixtures were identified at lake or lake-influenced sites than at riverine sites. As mixture complexity increased, the probability of a specific mixture occurring more often than by chance greatly increased, highlighting the importance of understanding source contributions to the environment. This empirically-based analysis of mixture composition and occurrence may be used to focus future sampling efforts or mixture toxicity assessments. 

 

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6. Maire, A., Laffaille, P., Maire, J.-F., & Buisson, L. (2016). Identification of Priority Areas for the Conservation of Stream Fish Assemblages: Implications for River Management in France. River Research and Applications, 33 (4), Pages 524–537.

Abstract:

Financial and human resources allocated to biodiversity conservation are often limited, making it impossible to protect all natural places, and priority areas for protection must be identified. In this study, we applied ecological niche models to predict fish assemblages in the stream network of France. Four non-correlated conservation objectives were derived from these species assemblages: taxonomic diversity, functional diversity, natural heritage importance and socio-economic value. We proposed a multi-objective prioritization method based on the Pareto optimality principle to rank the planning units (i.e. 6097 subcatchments) according to their inherent trade-offs between the four conservation objectives. Four types of hydrosystems  of great conservation importance presenting specific fish assemblages were identified: (i) the most upstream areas of large catchments; (ii) the most downstream areas of large catchments; (iii) the small coastal catchments of the English Channel and the Atlantic Ocean; and (iv) the Mediterranean streams of medium altitude. The fish assemblages characterizing these hydrosystems were complementary and representative of the entire fish fauna of France. Most of these priority subcatchments were found to be practically suitable for the implementation of conservation actions, which is very promising for the protection of river biodiversity.

 

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7. Jansen, P., Sabulis, M., & Clock, J. (2016). In Situ Solidification (ISS) of River Sediments: Pilot Demonstration and Discussion of ISS as a Remedial Alternative to Dredging and Capping. Remediation Journal, 26 (2), Pages 25–49.

Abstract:

In situ solidification (ISS) is a proven technology for remediation of upland site soils, but has not been thoroughly demonstrated for use in impacted underwater sediments. This article describes the first successful use of ISS techniques to solidify underwater sediments containing manufactured gas plant non-aqueous-phase liquid (NAPL). The techniques consisted of mixing cementitious grout with the sediments in situ to create a monolith that immobilized the contaminants, significantly decreased the hydraulic conductivity, and also vastly decreased contaminant leaching potential of the sediments. The success of this pilot demonstration project suggests that ISS may be a viable alternative for: sites requiring deep dredging; large volume projects on urban waterways where staging and amending areas are limited; sites with NAPL impacts that cannot be controlled during dredging; and sites where eventual NAPL breakthrough is anticipated if reactive caps are employed. The potential economic, environmental, and operational benefits of this technology will be discussed. This article focuses on the primary objectives of the pilot demonstration: to meet quantitative performance criteria for strength and hydraulic conductivity; to assess the leach performance of the solidified sediments; and to satisfy water quality parameters for turbidity, pH, and sheen. Approach/ activities: The pilot study utilized a customized marine platform (modular floats, tug boats, etc.) and full-scale ISS equipment (auger rig, silos, etc.) and varied operational parameters to provide a range of data to assist in evaluating the feasibility and efficacy of the technology for use in similar environments and in planning future ISS projects on the water. Water quality controls and monitoring were implemented during the operation, and the study documented and evaluated the environmental disruption (short-term impacts) and costs of the application of the ISS process to contaminated aquatic sediments.

 

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8. Machac, J., Hartmann, T., & Jilkova, J. (2017). Negotiating land for flood risk management : upstream-downstream in the light of economic game theory. Journal of Flood Risk Management, 11 (1), Pages 66–75.

Abstract:

This paper discusses the use of game theory as a method to achieve land and water governance for flood retention and resilience on a catchment scale. Therefore, it addresses flood retention in river catchments by using pay-off matrices of game theory. How do pay-off matrices between upstream and downstream change when certain property rights are adjusted or institutional conditions are changed? What if liability issues, responsibilities, and externalities of flood protection measures are reframed? Who should pay and who profit from retention measures? Individual scenarios correspond to some basic games from the game theory. The aim of these thought experiments is to develop rules for upstream downstream agreements on retention and resilience within a river basin area.

 

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9. Noda, K., Hamada, J., Kimura, M., & Oki, K. (2018). Debates over dam removal in Japan. Water and Environment Journal.

Abstract:

Japan is facing a severe problem with the aging of its infrastructure, including dams. We studied eight controversial cases (the Ararse, Okusawa, Setoishi, Tamayodo, Minochi, Yasuoka, Tsuga and Nibutani Dam) involving dam removal in Japan and elucidated the triggers and suggested reasons for the debate. Renewal of water rights was a major trigger in three of the eight cases. Environmental reasons in five cases were not relevant to the demolition decision regarding dams conferring public benefit, even if restoration of the river environment was a recognized benefit. Compared with single-purpose dams, the removal debate for a multipurpose dam, based on economic reasons regarding a single function, did not gain traction. Among the eight cases, there has been no case triggered by the renewal of water right by reason of economics, which should be highlighted options for stock management purposes.

 

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10. Ottosen, C. B., Rønde, V., Trapp, S., Bjerg, P. L., & Broholm, M. M. (2018). Phytoscreening for Vinyl Chloride in Groundwater Discharging to a Stream. Groundwater Monitoring & Remediation, 38 (1), Pages 66–74.

Abstract:

This study applies an optimized phytoscreening method to locate a chlorinated ethene plume discharging into a stream. To evaluate the conditions most suitable for successful phytoscreening, trees along the stream bank were monitored through different seasons with different environmental conditions and hence different uptake/loss scenarios. Vinyl chloride (VC) as well as cis-dichloroethylene (cis-DCE), trichloroethylene (TCE), and tetrachloroethylene (PCE) were detected in the trees, documenting that phytoscreening is a viable method to locate chlorinated ethene plumes, including VC, discharging to streams. The results reveal, that phytoscreening for VC is more sensitive to environmental conditions affecting transpiration than for the other chlorinated ethenes detected. Conditions leading to higher groundwater uptake by transpiration than contaminant loss by diffusion from the tree trunks are optimal (e.g., low relative humidity, plentiful hours of sunshine and an intermediate air temperature). Additionally, low precipitation prior to the sampling event is beneficial, as uptake of infiltrating precipitation dilutes the concentration in the trees. All chlorinated ethenes were sensitive to dilution by clean precipitation and in some months, this resulted in no detection of contaminants in the trees at all. Under optimal environmental conditions the tree cores allowed detection of chlorinated solvents and their metabolites in the underlying groundwater. Whereas, for less ideal conditions there was a risk of no detection of the more volatile VC. This study is promising for the future applicability of phytoscreening to locate shallow groundwater contamination with the degradation products of chlorinated solvents.

 

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11. Ren, Y., Guo, J., Lu, Q., Xu, D., Qin, J., & Yan, F. (2018). Polypropylene Nonwoven Fabric@Poly(ionic liquid)s for Switchable Oil/Water Separation, Dye Absorption, and Antibacterial Applications. ChemSusChem, 11 (6), Pages 1092–1098.

Abstract:

Pollutants in wastewater include oils, dyes, and bacteria, making wastewater cleanup difficult. Here, we propose the preparation of multifunctional wastewater treatment media, poly (ionic liquid) grafted polypropylene (PP) nonwoven fabrics (PP@PIL), prepared via a simple and scalable surface grafting process. The fabricated PP@PIL fabrics exhibited superior switchable oil/water separation (η > 99%) and dye absorption performance (q = 410 mg/g), as well as high antibacterial properties. The oil/water separation could be easily switched via anion-exchanging of PIL segments. Moreover, the multiple functions (oil/water separation, dye absorption, and antibacterial properties) occurred at the same time, and did not interfere with each other. The multifunctional fibrous filter could be easily regenerated by washing with an acid solution, and the absorption capacity is maintained after many recycling tests. These promising features make PIL grafted PP nonwoven fabric a potential one-step treatment for multicomponent Wastewater.

 

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12. Seidel, M., Voigt, M., Langheinrich, U., Hoge-Becker, A., Gersberg, R. M., Arévalo, J. R., & Lüderitz, V. (2017). Re-Connection of Oxbow Lakes as an Effective Measure of River Restoration. CLEAN - Soil, Air, Water, 45 (3), 1600211.

Abstract:

Six years after re-connection of an oxbow lake from periodically to permanently connected to the main channel, the restoration success was assessed. This permanently connected oxbow lake was compared with the main channel of the Elbe River and with a periodically connected oxbow lake by means of comparisons of the aquatic macroinvertebrates, fish and aquatic macrophyte communities. The permanently connected oxbow was suited as important replacement habitat for riverine invertebrates, especially for clubtails (Odonata) and unionid mussels (Bivalvia). The periodically connected oxbow lake was colonized by typical species for shallow lakes. As expected, riverine species did not occur. Meanwhile, the invertebrate community in the main channel was poor and dominated by invasive species (Dikerogammarus villosus, Dreissena polymorpha). The results concerning fish showed a clear dominance of the rheophilic species spined loach (Cobitis taenia) in the permanently connected oxbow lake and of the indifferent species roach (Rutilus rutilus) and European perch (Perca fluviatilis) in the periodically connected oxbow lake. However, species number was highest in the main channel. For macrophytes, quantity, number of taxa and growth forms and diversity were lower in the permanently compared to the periodically connected oxbow lake. In conclusion, the re-connection of oxbow lakes to main channels can be an important measure for native species conservation, especially macroinvertebrates, and hence for the implementation of the Water Framework Directive.

 

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13. Foster, S. G., & Rood, S. B. (2017). River regulation and riparian woodlands: Cottonwood conservation with an environmental flow regime along the Waterton River, Alberta. River Research and Applications, 33 (7), Pages 1088–1097.

Abstract:

Following water withdrawal, riparian cottonwoods have declined downstream from some dams in western North America. Analyses of aerial photographs and field observations in the 1980s suggested that the black and narrowleaf cottonwoods (Populus trichocarpa and Populus angustifolia) along the Waterton River, Alberta, were declining due to drought stress following the 1964 damming and diversion. This raised concern for the riverine ecosystems and in 1991, “functional flows” commenced with 2 changes: (a) the minimum flow was increased from 0.9 to 2.3 m3/s (mean discharge 21.9 m3/s) and (b) flow ramping provided gradual stage recession after the spring peak. This provided an environmental flow regime that was delivered for 2 decades and this study investigated the consequent river flow patterns and riparian woodlands upstream and downstream from the Waterton Dam. Analyses of aerial photographs from 1951 to 2009 assessed 4 flow management intervals: (a) the free‐flowing predam condition, (b) the initial dammed interval to the mid‐1970s, (c) a drought interval in the 1980s, and (d) with the environmental flow regime after 1991. Analyses revealed woodland reduction from 1961 to 1985 due to losses through bank erosion with major floods and apparent decline due to low flows following a regional drought and water withdrawal for irrigation. With the subsequent environmental flow regime, there was apparent woodland recovery, despite drought in 2000 and 2001. This study demonstrated that the correspondence between river flow patterns and the extent of riparian woodlands and the benefit from the environmental flow regime that probably reduced drought stress and mortality.

 

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14. Dunham, J. B., Angermeier, P. L., Crausbay, S. D., Cravens, A. E., Gosnell, H., McEvoy, J., … Sanford, T. (2018). Rivers are social-ecological systems: Time to integrate human dimensions into riverscape ecology and management. Wiley Interdisciplinary Reviews: Water, 5 (4), e1291.

Abstract:

Incorporation of concepts from landscape ecology into understanding and managing riverine ecosystems has become widely known as riverscape ecology. Riverscape ecology emphasizes interactions among processes at different scales and their consequences for valued ecosystem components, such as riverine fishes. Past studies have focused strongly on understanding the ecological processes in riverscapes and how human actions modify those processes. It is increasingly clear, however, that an understanding of the drivers behind actions that lead to human modification also merit consideration, especially regarding how those drivers influence management efficacy. These indirect drivers of riverscape outcomes can be understood in the context of a diverse array of social processes, which we collectively refer to as human dimensions. Like ecological phenomena, social processes also exhibit complex interactions across spatiotemporal scales. Greater emphasis on feedbacks between social and ecological processes will lead scientists and managers to more completely understand riverscapes as complex, dynamic, interacting social– ecological systems. Emerging applications in riverscapes, as well as studies of other ecosystems, provide examples that can lead to stronger integration of social and ecological science. We argue that conservation successes within riverscapes may not come from better ecological science, improved ecosystem service analyses, or even economic incentives if the fundamental drivers of human behaviors are not understood and addressed in conservation planning and implementation.

This article is categorized under:

Water and Life > Stresses and Pressures on Ecosystems

Human Water > Water Governance

Engineering Water > Planning Water

 

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15. Barnes, J. (2017). The future of the Nile: climate change, land use, infrastructure management, and treaty negotiations in a transboundary river basin. Wiley Interdisciplinary Reviews: Climate Change, 8 (2), e449.

Abstract:

The Nile is one of the world’s major rivers; its basin is shared by 11 countries and is home to some 300 million people. This article reviews the multidisciplinary literature on the Nile to understand more about the outlook for this geopolitically significant river basin. I start by synthesizing the key results from recent climate change modeling studies, which show a warming trend for the basin, but considerable uncertainty regarding the direction of precipitation and streamflow change. I explore how different actors within the Nile Basin are perceiving and responding to climate change. Second, I look at the significance of land use, both to basin hydrology and as a driver of water demand. I highlight contemporary land use changes that could impact flows within the Nile Basin. Third, I examine the role of infrastructure in influencing the magnitude and temporality of flows along the river. I focus, in particular, on the Grand Ethiopian Renaissance Dam, its projected impacts, and the concerns it has generated. Finally I explore the geopolitical context of the basin, and the ongoing conflict over water sharing agreements. I look at the treaty currently on the table, the Cooperative Framework Agreement, and the political issues it has raised. In bringing together this diverse literature, the article offers a timely and multifaceted insight into the varied factors that will shape the future of the Nile. 

 

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16. Taylor, S. W., & Guha, H. (2016). Time and Magnitude of Peak Concentration of Reactive Groundwater Contaminants Discharged to a River. Groundwater, 55 (1), Pages 63–72.

Abstract:

An analytical solution for calculating the contaminant discharge rate in an aquifer following an instantaneous release of reactive contaminant mass to groundwater is used to derive relationships for the time and magnitude of peak concentration in a river receiving the transported material. Relationships are developed for the time of peak concentration relative to the time of travel for the contaminant, and the magnitude of peak concentration relative to the concentration calculated at the time of travel. Both quantities are found to be a function of two dimensionless parameters characterizing advective-dispersive-reactive transport—the Peclet number and the Damkohler number. It is shown that the time to peak concentration may occur before the time of travel, considering advection and retardation only, depending on the magnitudes of the Peclet and Damkohler numbers. Similarly, the magnitude of peak concentration may exceed the concentration calculated assuming that the time of peak concentration coincides with time of travel for the contaminant. For large Damkohler numbers, equating the time of peak concentration with the time of travel for the contaminant can significantly underestimate peak concentrations.

 

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17.  Wang, K., & Lin, Z. (2018). Characterization of the nonpoint source pollution into river at different spatial scales. Water and Environment Journal.

Abstract:

The objectives of this study were to investigate the effects of rainfall and underlying surface conditions on nonpoint source (NPS) pollution loads and to identify the uncertainty in NPS pollution loads at different spatial scales in the Fuxi River basin, China. Data on monitored daily flow rates and concentrations of ammonium nitrogen, total nitrogen, total phosphorus and permanganate index at the sub-basin and basin scales were collected for a period from 2013 to 2015. Dynamic time warping distance and information measures were used to characterize pollution loads and determine the uncertainties. The results indicate that, at both sub-basin and basin scales, NPS pollution loads increased nonlinearly with rainfall until it reached 38.4 mm, and subsequently, the NPS pollution loads stabilized. The underlying surface conditions affected the NPS pollution loads more profoundly than rainfall. Additionally, the uncertainty in NPS pollution loads increased with the spatial scales.

 

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18. Whitmore, K. M., Schoenholtz, S. H., Soucek, D. J., Hopkins, W. A., & Zipper, C. E. (2018). Selenium Dynamics In Headwater Streams Of The Central Appalachian Coalfield. Environmental Toxicology and Chemistry.

Abstract:

Coal mining can cause selenium (Se) contamination in US Appalachian streams, but linkages between water-column Se concentrations and Se bioaccumulation within Appalachian headwater streams have rarely been quantified. Using elevated specific conductance (SC) in stream water as an indicator of mining influence, we evaluated relationships between SC and Se concentrations in macroinvertebrates and examined dynamics of Se bioaccumulation in headwater streams. Twenty-three Appalachian streams were categorized into 3 stream types based on SC measurements: 1) reference streams with no coalmining history; 2) mining-influenced, high-SC streams; and 3) mining-influenced, low-SC streams. Selenium concentrations in macroinvertebrates exhibited strong positive associations with both SC and dissolved Se concentrations in stream water. At 3 streams of each type, we further collected water, particulate matter (sediment, biofilm, leaf detritus), and macroinvertebrates and analyzed them for Se during 2 seasons. Enrichment, trophic transfer, and bioaccumulation factors were calculated and compared among stream types. Particulate matter and macroinvertebrates in mining-influenced streams accumulated high Se concentrations relative to reference streams. Concentrations were found at levels indicating Se to be a potential environmental stressor to aquatic life. Most Se enrichment, trophic transfer, and bioaccumulation factors were independent of season. Enrichment factors for biofilm and sediments and bioaccumulation factors for macroinvertebrate predators varied negatively with water-column Se. Our results increase scientific understanding of Se bioaccumulation processes in Appalachian headwater streams.

 

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Marine Science

 

1. Altenritter, M. N., Zydlewski, G. B., Kinnison, M. T., & Wippelhauser, G. S. (2017). Atlantic Sturgeon Use of the Penobscot River and Marine Movements within and beyond the Gulf of Maine. Marine and Coastal Fisheries, 9 (1), pages 216–230.

Abstract:

Atlantic Sturgeon Acipenser oxyrinchus oxyrinchus were recently listed as threatened in the Gulf of Maine and endangered in the rest of their U.S. range. Continued research priorities include long-term population monitoring, identifying the species’ spawning and nursery grounds, and determining its use of estuaries and marine coastal waters. Although recent and ongoing research is filling in knowledge gaps, the Atlantic Sturgeon’s life history and its severely depleted populations make this a challenging species to fully characterize. Our goal was to compile data collected over 7 years from fish captured in the Penobscot River estuary, Maine, to inform management decision making. Atlantic Sturgeon were captured (n = 199), recaptured (n = 16), and passively telemetered (n = 32 that were analyzed here) from 2006 to 2013. Captured individuals were predominantly subadults, and data fromtelemetry indicated repeated use of a 5-km reach of the mesohaline portion of the estuary. Subadults predictably emigrated from the river each fall (mean date ± SD, August 31 ± 43.5 d) and immigrated back each spring to early summer (May 15 ± 27.8 d), with most individuals (>95% [31 of 32]) returning one or more years after tagging. Marine detections of these subadults were common (81.25% [26 of 32]) and spanned the geographic extent of both the threatened and endangered U.S. distinct population segments and into international waters, e.g., from the Hudson River, New York, to Minas Basin, Nova Scotia. However, they were more typically detected by receivers in the Gulf of Maine; 77% (20 of 26) were only detected in the Gulf of Maine when not in the river. These data indicate that, based on the temporal and spatial predictability of habitat use, the estuary of the Penobscot River is important for subadult Atlantic Sturgeon of the Gulf of Maine. The wider movement patterns emphasize the need for conservation and management across regions and international boundaries.

 

2. Andrews, S. N., Linnansaari, T., Curry, R. A., & Dadswell, M. J. (2017). The Misunderstood Striped Bass of the Saint John River, New Brunswick: Past, Present, and Future. North American Journal of Fisheries Management, 37 (1), Pages 235–254.

Abstract:

The Striped Bass Morone saxatilis of the Saint John River, New Brunswick, is an enigma, having now existed in a state of uncertain species status for more than four decades. Despite a well-established historical record of adult occurrence in large numbers, the available literature, historical accounts, and status reports contain no evidence for the persistence of a native, reproducing Striped Bass population. In 2012, the Committee on the Status of Endangered Wildlife in Canada listed the Saint John River Striped Bass as endangered as part of the Bay of Fundy design a table unit. This listing lacked current peer-reviewed literature and based its conclusions predominately on restatements of findings and opinions from the 1970s and 1980s. After the apparent failure of Striped Bass spawning in the 1975, the decline of native Saint John River Striped Bass was accredited to many factors ranging from chemical pollutants to overfishing to the installation of a sizeable hydropower facility. Modest attempts to locate eggs and juveniles of the native species have been taken; however, the results have been inconclusive due to ineffective, infrequent, and poorly timed sampling. Here we reviewed all available information, literature, reports, and data to effectively describe the Saint John River Striped Bass population in an effort to help manage and recover (if required) this apparently missing population.

 

3. Lewisch, E., Unfer, G., Pinter, K., Bechter, T., & El-Matbouli, M. (2018). Distribution and prevalence of T. bryosalmonae in Austria: A first survey of trout from rivers with a shrinking population. Journal of Fish Diseases.

Abstract:

The first evidence of proliferative kidney disease (PKD) in an Austrian river (the River Kamp) was documented in 2016, and no information on the PKD infection status of trout in other rivers was available. Since then, brown trout (Salmo trutta fario) and rainbow trout (Oncorhynchus mykiss) have been collected from rivers in Upper and Lower Austria for different diagnostic purposes. In this study, we summarize the recent findings of a first survey concerning the distribution of Tetracapsuloides bryosalmonae, the causative agent of proliferative kidney disease (PKD), from these samples. Between September 2015 and October 2017, a total of 280 brown trout and 39 rainbow trout were collected from 21 rivers in the provinces of Upper and Lower Austria. T. bryosalmonae was detected by PCR of kidney tissue in 17 of 21 sampled rivers and in 138 of 280 brown trout as well as in 11 of 39 rainbow trout. Pathological signs of PKD (e.g., hypertrophy of the kidney) were observed in 33 analysed brown trout and six rainbow trout samples. No correlations between fish infected by T. bryosalmonae and the parameters size and age class, condition factor, geological origin of the streams and distribution within the river course were found, while positively tested fish are significantly increased at sampling sites exceeding water temperatures of 15°C for median periods of 115 days. The prevalence within the affected streams or stream sections is highly variable, and in single rivers, infection rates of up to 90% are confirmed.

 

4. Kern, A. I., Sammons, S. M., & Ingram, T. R. (2017). Habitat Use by Telemetered Alabama Shad During the Spawning Migration in the Lower Flint River, Georgia. Marine and Coastal Fisheries, 9 (1), Pages 320–329.

Abstract:

The Alabama Shad Alosa alabamae is an anadromous clupeid that lives in the northern Gulf of Mexico and ascends freshwater rivers in spring to spawn. Populations have experienced substantial range-wide declines due to habitat alteration. The largest known population of Alabama Shad is found in the Apalachicola River in northwest Florida. To assess their movement during the spawning migration, 250 Alabama Shad were fitted with acoustic or radio transmitters, depending on year, and transported upstream from Jim Woodruff Lock and Dam during 2010–2014. The 153 relocations from 126 individual fish revealed congregation areas that were suspected to be spawning locations. Alabama Shad selected limerock boulder substrate, avoided limerock fine and rocky substrates and used sandy substrate in the same proportion as its availability. Alabama Shad upstream movement was greatest during April through mid-May. Movements ≥ 20 km were generally clustered together over a period of a few days, with ~90% of such movements occurring following periods of increased river discharge. All limerock boulder substrate areas on the lower Flint River were identified to focus future efforts to determine exact spawning locations.

 

5. Huchzermeyer, K. D. A., Woodborne, S., Osthoff, G., Hugo, A., Hoffman, A. C., Kaiser, H., … Myburgh, J. G. (2017). Pansteatitis in polluted Olifants River impoundments: nutritional perspectives on fish in a eutrophic lake, Lake Loskop, South Africa. Journal of Fish Diseases, 40 (11), Pages 1665–1680.

Abstract:

This study compares the aetiology of pansteatitis in Lake Loskop, relative to two other impoundments along the Olifants River. Macroscopic and microscopic pathology, age determination and analysis of stomach content, fatty acids and stable isotopes explain the high prevalence of pansteatitis in Oreochromis mossambicus (Peters) and several other species in Lake Loskop. All the dietary indicator comparisons between pansteatitis-affected and healthy fish fail to support a systemic cause. Pansteatitis in Lake Loskop was linked to size and weight of O. mossambicus, but not to ontogenic age. Fish in Lake Loskop showed abnormally high omega-3 to omega-6 fatty acid ratios normally only found in marine fish with no significant difference in degree of assimilation of these fatty acids between pansteatitis-affected and healthy fish. This explains the vulnerability to, but not the occurrence of, pansteatitis. As a cause for the pansteatitis, these results point towards sporadic vitamin E-depleting trigger events, known sporadic fish die-off occurrences that provide surviving fish with a rich source of rancid fats on which to scavenge. The mechanism ties pansteatitis to eutrophication and trophic cascade effects, the intrinsic drivers of the disease and suggests an adaptive management strategy that might be applied by relevant conservation authorities.

 

6. Goble, C. W., Auer, N. A., Huckins, C. J., Danhoff, B. M., Holtgren, J. M., & Ogren, S. A. (2018). Fish Distributions and Habitat Associations in Manistee River, Michigan, Tributaries: Implications for Arctic Grayling Restoration. North American Journal of Fisheries Management, 38 (2), Pages 469–486.

Abstract:

Restoration and enhancement of North American native freshwater fishes have for several decades been the subject of growing interest among fisheries biologists, natural resource managers, non-governmental organizations, and the sportfishing public. The Little River Band of Ottawa Indians (LRBOI) and the Michigan Department of Natural Resources (MDNR), along with universities and public interest groups, are re-examining the potential for re-introduction of the Arctic Grayling Thymallus arcticus, a species that has been extirpated in Michigan since the 1930s. The Manistee River, Michigan, flows through the LRBOI’s reservation and once supported the last known native Arctic Grayling population in the state’s Lower Peninsula. The objectives of this study were to (1) identify potential biotic limitations, such as competition and/or predation from other fish species that may interfere with Arctic Grayling reintroduction in the Manistee River watershed; and (2) describe how instream habitat features currently relate to populations of potentially interacting species. Field surveys conducted during June–August 2012 in eight Manistee River tributaries identified suitable abiotic habitat for Arctic Grayling in 20 of 22 sampling reaches. However, high densities of Brown Trout Salmo trutta (a nonnative salmonid) may have influenced some of the habitat associations observed for Brook Trout Salvelinus fontinalis and Slimy Sculpin Cottus cognatus, two species that currently and historically co-occurred in Arctic Grayling habitats. These two species were the most abundant in river reaches with Brown Trout densities less than 0.10 fish/m2. Based on habitat conditions and Brown Trout densities, there appear to be four distinct tributary regions for which management strategies could be developed to enhance the success of Arctic Grayling re-introduction efforts. Re-introduction of Arctic Grayling in the Manistee River watershed would support LRBOI and MDNR goals for native species restoration and would provide a unique and historic angling opportunity that has been absent in Michigan for nearly 100 years.