pinecone/core-2020-05-10-deduplication huggingface dataset:
Fish body condition and recruitment responses to antecedent flows in dryland rivers are species and river specific

Dryland rivers in arid and semi-arid regions drain approximately one-third of the Earth's land area, yet basic aspects of their ecology are poorly documented and many are threatened by excessive water use leading to alterations of the flow regime. Management of dryland rivers imperilled by changes to the flow regime requires quantitative hydro-ecological relationships and models to support environmental flow restoration strategies and to define ecological response indicators for assessment of trends in ecological health. Fish living in dryland rivers experience highly variable levels of food resources associated with 'boom and bust' productivity patterns driven by highly irregular episodes of rainfall, runoff and floodplain inundation followed by busts associated with drying of remnant aquatic habitats. To cope with variable food resource levels, fish store energy as fat during productivity booms, enabling them to breed later or to survive through extended periods of limited food resources. This study tracked temporal patterns of body condition and recruitment success of the four most abundant fish species in two Australian dryland river systems with contrasting patterns of flow variability, Cooper Creek and the Moonie River. We found consistent responses to flow magnitude and timing for body condition and/or recruitment success in Cooper Creek but fewer responses in the Moonie River. Results suggest that the fish metrics and relationships to flow established for Cooper Creek may apply in similar dryland rivers exhibiting clear boom and bust patterns, whereas the Moonie River results could be applicable to rivers with less variable flow patterns and fewer spells of zero flows. Our study demonstrates that simple, non-destructive methods based on fish length and weight provide useful biological indicators of response to flow variability provided that care is taken with species selection and that hydro-ecological relationships are calibrated for each contrasting type of hydrologic regime.Griffith Sciences, Griffith School of EnvironmentFull Tex
Diatoms of temporary and permanent watercourses in Southern Europe (Portugal)

The potential importance of benthic diatoms in Mediterranean watercourses has received limited academic attention historically. This study sought to provide baseline information for this poorly studied group. Temporary and permanent watercourses in Portugal differ in catchment characteristics, climatic variables and water chemistry. The benthic diatom communities were characterized in terms of ecological preferences and conservation status for taxa with relative abundance above 1% in at least one site covering 39 temporary sites (109 taxa) and 53 permanent sites (130 taxa). The low-profile guild dominated both temporary and permanent watercourses, followed by the high-profile and motile guilds. Indicator value analysis indicated that Amphora copulata, Cocconeis placentula, Diploneis separanda, Encyonopsis subminuta, Fragilaria radians, Gomphonema olivaceum, Gomphonema truncatum, Halamphora veneta, Navicula radiosa, Navicula veneta, Sellaphora seminulum and Ulnaria acus were indicators of temporary watercourses, whereas Encyonema minutum, Eunotia minor, Fragilaria rumpens, Fragilaria cf. socia and Navicula rhynchocephala were characteristic of permanent watercourses. Ecological preferences of indicator taxa were inferred on the basis of environmental variables that differed significantly between temporary and permanent watercourses. The importance of temporary watercourses for the maintenance of diatom biodiversity is discussed and explored
Fate, transport and effects of pollutants originating from acid mine drainage in the Olifants River, South Africa

Concentrations of pollutants were measured in water, sediment and algal samples collected along a
longitudinal gradient from a stretch of the Olifants River, South Africa, that receives AMD from the
Klipspruit River. The effects of AMD were determined through macroinvertebrate biotic indices
(SASS5) and multivariate analysis of macroinvertebrate communities. The acidic Klipspruit River
caused increased concentrations of total Al, Fe and Mn in the Olifants River. Upon mixing of the
Klipspruit with that from the alkaline Olifants River, Al and Fe precipitate rapidly, leading to lower
concentrations in the dissolved phase and higher concentrations in the suspended phase and in
sediment at sites in close proximity to the confluence. Similarly filamentous algae accumulated high
concentrations of Al, Fe and Zn immediately after the confluence. Mn remains in the dissolved phase
and sediment and algal concentrations increase with increasing distance downstream. Metal speciation
analysis indicate that Al is rapidly converted from more toxic forms (e.g., Al3+ and Al(OH)2+) to less
toxic forms (e.g., Al(OH)3(aq) and Al(OH)4-). In contrast, Mn remains in the soluble Mn2+ form.
Macroinvertebrate metrics and community structure showed clear signs of deterioration in water
quality in the Olifants River downstream of the point of AMD input . While total TDS concentrations
at all sites fall within ranges likely to affect macroinvertebrates, the relative composition of major ions
changes as a result of AMD input, which may also account for the observed changes in
macroinvertebrate communities. Further downstream, the Wilge River discharges into the Olifants
River, and significantly improves water quality downstream of the confluence. Future mining and
development activities in the Wilge catchment should be carefully managed and monitored so as to
ensure sufficient flows of acceptable quality to prevent further deterioration of water quality in the
Olifants River and downstream reservoirs.Olifants River Forum, the National Research Foundation (THRIP Grant) and CSIR Parliamentary grant (Project No. ECWH025).http://onlinelibrary.wiley.com/journal/10.1002/(ISSN)1535-14672015-08-30hb201
Life-history plasticity of riparian annual plants adapted to extreme variations in water level: mesocosm experiments

The riparian zones of reservoirs associated with regulated rivers in China experience annual fluctuations in water level of up to 30 m that may vary in timing from year to year. Few plant species can tolerate such hydrological perturbation but short-lived riparian annuals might be evolutionarily pre-adapted to such conditions. This study investigated plasticity of life history in four annual species: one typically associated with free-flowing rivers (Panicum bisulcatum) and three that colonize reservoir margins (Cyperus michelianus, Fimbristylis miliacea and Eclipta prostrata). We found that all four species produced non-dormant seeds that survived prolonged submergence; germination percentage was independent of the time of exposure by receding waters. Although growth was reduced as a result of shorter growing seasons, all four species completed their life cycles and produced seeds before winter. In addition, P. bisulcatum and C. michelianus allocated biomass to seed production, at the expense of roots and stems, in response to later establishment. All species responded to later establishment with a reduced vegetative growth period before seed production. C. michelianus, F. miliacea and E. prostrata could also delay the onset of flowering time by up to 2 months. P. bisulcatum, a plant that can flower only after exposure to short days, consequently had a fixed flowering time and could accommodate delayed establishment only with a progressively shorter period of vegetative growth. This lower flexibility might explain its absence from reservoir margins. The conceptual framework presented here offers a tool to predict the establishment of vegetation under hydrological disturbance in riparian environments and thereby provides insights into improved restoration practice
Monitoring of river contamination derived from acid mine drainage using airborne imaging spectroscopy (HyMap data, South-West Spain)

Imaging spectroscopy is used in this work as an essential mapping tool to monitor changes in contaminated river sediments. Multidate hyperspectral image data (HyMap) are utilized to identify spatial mineral patterns, to detect temporal changes in mineralogy and to link these changes with geochemical processes and short-term climate characteristics.\ud
River sediments contaminated by acid mine drainage are covered by crusts with variably hydrated iron sulphate. The mineralogy of the crusts and the grain size of the underlying fluvial sediments overlap. The spectra used to build up maps from HyMap data are diagnosed mineralogically with archive spectral libraries from pyrite oxidation minerals from well-known sequences of minerals.\ud
The maps compiled from hyperspectral imagery display generalized oxidation shown by the coatings over river sediments following warm and dry periods with low water level. After the wet periods, the area covered by oxidized mineralogical phases recedes in favour of hydrated sulphate.\ud
The iteration of image processing algorithms and the mineralogical and potential contamination in a geological context are described. Change detection of the mineral crusts on the river sediments by mapping using hyperspectral remote sensing data may thus enable a quantitative and qualitative environmental evaluation by the regulators
Secondary production of highly unsaturated fatty acids by zoobenthos across rivers contrasting in temperature

Highly unsaturated fatty acids (HUFA), namely eicosapentaenoic acid (20:5n-3, EPA) and docosahexaenoic acid (22:6n-3, DHA), which are essential for many animals, including humans, are mainly produced in aquatic trophic webs. In fast-flowing rivers, macrozoobenthos is the main source of HUFA for fish and may be particularly vulnerable to thermal alterations associated with climate change. We studied benthic communities in a unique natural ecosystem: the Yenisei River downstream of the dam of Krasnoyarsk Hydroelectric Power Station with very low temperature in summer because of discharge of cold water from deep in the reservoir and its tributaries with high summer temperature. This ‘natural experiment’ allowed to get rid of confounding factors, such as differences in light, seasonality, geology (biogeochemistry) and biogeography (regional species pools). As found, in spite of an increase of biodiversity and rates of daily production in warm rivers compared with cold sites, DHA and partly EPA production of zoobenthos decreased with the increase of temperature because of changes in species composition. Thus, in a climate warming context, we can predict a decrease of production of these HUFA by river zoobenthos and thereby a diminishing of their supply for fish and next to humans
Hydrogeomorphology-ecology interactions in river systems

The European Union-funded REFORM (REstoring rivers FOR effective catchment Management) project has developed guidance and tools aimed at making river restoration and mitigation measures more effective. A major component of this work has been to investigate functional linkages between the hydrogeomorphology and ecology of rivers. This special collection presents some of the outputs from this work concerning interactions between hydrological, geomorphological and ecological processes in naturally functioning river systems. Together, this set of five papers reviews some of the existing knowledge on interactions and feedbacks between hydrogeomorphology and ecology in river systems and outlines how hydrogeomorphological processes, ecological processes and plant traits contribute to driving river corridor dynamics that create and sustain a diversity of aquatic and wetland habitats that support fish communities
The accuracy and reliability of traditional surface flow type mapping : is it time for a new method of characterizing physical river habitat?

Surface flow types (SFTs) are advocated as ecologically relevant hydraulic units, often mapped visually from the bankside to characterize rapidly the physical habitat of rivers. SFT mapping is simple, non-invasive and cost-efficient. However, it is also qualitative, subjective and plagued by difficulties in recording accurately the spatial extent of SFT units. Quantitative validation of the underlying physical habitat parameters is often lacking and does not consistently differentiate between SFTs. Here, we investigate explicitly the accuracy, reliability and statistical separability of traditionally mapped SFTs as indicators of physical habitat, using independent, hydraulic and topographic data collected during three surveys of a c. 50 m reach of the River Arrow, Warwickshire, England. We also explore the potential of a novel remote sensing approach, comprising a small unmanned aerial system (sUAS) and structure-from-motion photogrammetry (SfM), as an alternative method of physical habitat characterization. Our key findings indicate that SFT mapping accuracy is highly variable, with overall mapping accuracy not exceeding 74%. Results from analysis of similarity tests found that strong differences did not exist between all SFT pairs. This leads us to question the suitability of SFTs for characterizing physical habitat for river science and management applications. In contrast, the sUAS–SfM approach provided high resolution, spatially continuous, spatially explicit, quantitative measurements of water depth and point cloud roughness at the microscale (spatial scales ≤1 m). Such data are acquired rapidly, inexpensively and provide new opportunities for examining the heterogeneity of physical habitat over a range of spatial and temporal scales. Whilst continued refinement of the sUAS–SfM approach is required, we propose that this method offers an opportunity to move away from broad, mesoscale classifications of physical habitat (spatial scales 10–100 m) and towards continuous, quantitative measurements of the continuum of hydraulic and geomorphic conditions, which actually exists at the microscale
The Effects of Replacing Native Forest on the Quantity and Impacts of In-Channel Pieces of Large Wood in Chilean Streams

Dead trees in rivers can significantly affect their morphological and ecological properties by increasing flow resistance, affecting sediment transport, and storing organic matter. Logs are usually recruited from banks or along the entire upstream basin. Although it is generally acknowledged that forested headwater streams feature higher volumes of in-channel pieces of large wood, the influence of forest type and forest management of the potential recruitment zone on the volumes and effects of wood have been less explored, especially in relation to the effects of replacing native forests with pine plantations. This paper presents a comparison of volumes of wood, and characteristics and effects on streams draining paired basins with comparable slopes, areas, and hydrologic regimes, but different in terms of land use. The five selected pairs of basins are located in the Coastal and Andean mountain Ranges in central Chile, in order to compare native forest and pine plantation basins. The results show that logs tend to be shorter and with larger diameters in streams draining native forest basins. Because of their smaller dimensions, logs and jams tend to be more mobile and oriented parallel to the flow. Volumes of in-channel wood in native forest basins are only slightly larger than in pine plantation basins, and no differences have been identified in terms of morphological effects on channel geometry. Also, fish type and biomass were comparable among pairs. Evidence highlights the importance of the width of riparian buffers in mitigating the effects of land use change, especially the substitution of native forest with plantations
The impacts of natural flood management approaches on in-channel sediment quality

Natural Flood Management (NFM) techniques aim to reduce downstream flooding by storing and slowing the flow of stormwater to river channels. These techniques include a range of measures, including setback stormwater outfalls and the physical restoration of channels and floodplains, to improve the natural functioning of catchments. An additional benefit of NFM measures is the potential reduction in sediment and pollutant delivery to the channel. Urban development releases a variety of heavy metal and nutrient pollutants that enter rivers through stormwater outfalls with adverse effects on the aquatic ecosystem. In this study, the influence of channel modification and quality of the river habitat on the sediment quality surrounding stormwater outfalls was assessed. Sediment samples were taken at several outfalls within the Johnson Creek catchment, Oregon, USA, and analysed for a variety of urban pollutants. The level of river habitat quality and modification at each site were assessed using a semi-quantitative scoring methodology. Significant increases in pollutant levels were observed at outfalls, with a greater and more variable increase at direct compared to setback outfalls. Removal efficiency of certain pollutants was found to be significantly correlated to the level of habitat quality or modification (for Fe, Ba, Sn, Mg, P, K) indicating that more natural reaches had greater potential for pollutant removal. The findings highlight the multiple benefits associated with NFM and river restoration approaches in relation to sediment quality and pollutant content
Quantifying Submerged Deposited Fine Sediments in Rivers and Streams Using Digital Image Analysis

Deposited fine sediment is an essential component of freshwater ecosystems. Nonetheless, anthropogenic activities can modify natural fine sediment levels, impacting the physical, chemical and biological characteristics of these ecosystems. An ability to quantify deposited fine sediment is critical to understanding its impacts and successfully managing the anthropogenic activities that are responsible for modifying it. One widely used method, the visual estimate technique, relies on subjective estimates of particle size and percentage cover. In this paper, we present two novel alternative approaches, based on non-automated digital image analysis (DIA), which are designed to reduce the subjectivity of submerged and surficial fine sediment estimates, and provide a verifiable record of the conditions at the time of sampling. The DIA methods were tested across five systematically selected, contrasting temperate stream and river typologies, over three seasons of monitoring. The resultant sediment metrics were strongly, positively correlated with visual estimates (rs = 0.90, and rs = 0.82, p &lt; 0.01), and similarly strongly, but negatively correlated with a sediment-specific biotic index, suggesting some degree of biological relevance. The DIA technique has the potential to be a valuable tool for application in numerous areas of river research, where a non-destructive, less subjective and verifiable method is desirable
The complexities of measuring fine sediment accumulation within gravel-bed rivers

This is an Open Access Article. It is published by Wiley under the Creative Commons Attribution 4.0 International Licence (CC BY). Full details of this licence are available at: http://creativecommons.org/licenses/by/4.0/Fine sediment storage within gravel beds is a key component of catchment sediment budgets and affects the health of benthic and hyporheic habitats. Here, we assess the performance of two substrate infiltration traps for the characterization of fine sediment ( < 2 mm) accumulation. One design, the vertically extending sediment trap, permits both lateral and vertical exchange in the sediment column, whereas the second type, a more traditional fixed-area sediment trap with impermeable side walls, permits only vertical exchange. Traps were deployed at three sites on the River Tame, Birmingham (UK), over varying installation periods (14-401 days). Results indicate that the facilitation of multiple pathways of exchange within the vertically extending sediment traps (vertical and lateral) resulted in a significantly greater amount of fine sediment being accumulated than in adjacent fixed-area sediment traps. This suggests that lateral transport is an important component contributing to fine sediment accumulation. However, there are notable and inherent problems associated with the use of different types of sediment trap and in the way the data should be presented and interpreted. This paper discusses the practical implications of the study findings and reflects on the complexities of undertaking accurate sediment deposition measurements in the field
The scale problem in tackling diffuse water pollution from agriculture : insights from the Avon Demonstration Test Catchment programme in England

Mitigation of diffuse water pollution from agriculture is of concern in the United Kingdom, so that freshwater quality can be improved in line with environmental objectives. Targeted on-farm mitigation is necessary for controlling sources of pollution to rivers; a positive impact must also be delivered at the subcatchment and catchment scales before good ecological status can be achieved. A farm on the River Sem in the Hampshire Avon Demonstration Test Catchment was selected for monitoring due to its degraded farmyard, track, and drainage ditch, which was targeted by the Demonstration Test Catchment programme for improvement using a treatment train of interventions. The river was monitored before and after, upstream and downstream, of the potential sources of pollution and subsequent mitigation, both locally at farm scale, and downstream at the subcatchment scale. Sediment was obtained from the riverbed using a conventional disturbance technique, and source samples were collected from across the subcatchment. Samples were analysed for geochemistry, mineral magnetism, and environmental radionuclide activity using the <63-μm fraction, before sediment source fingerprinting was conducted to apportion sources. Source tracing revealed that, although the degraded farm track was experiencing channelized flow and erosion in the pre-mitigation period, it was not a major sediment source even at farm scale. Repeat source apportionment during the pre- and post-mitigation periods showed that the targeted treatment train did not result in statistically significant decreases in predicted contributions from the farm track sources at either scale. Sediment sources must be determined at a range of spatial scales to support effective mitigation
Application of the Proportion of Sediment-sensitive Invertebrates (PSI) biomonitoring index

Sedimentation of river beds is a key pressure impacting riverine ecological communities. Research has identified the need for new approaches to help demonstrate and quantify the impacts of excessive fine-sediment deposition on benthic macroinvertebrate populations. To help meet this requirement, the Proportion of Sediment-sensitive Invertebrates (PSI) methodology was developed and has been in operational use in the United Kingdom for several years. This paper presents a number of case studies, at both national and local scales, showing how the method can be used to identify point and nonpoint fine-sediment pollution, as well as demonstrating the analysis of a national dataset to describe the relationship between PSI and a channel substrate index. A novel approach to displaying PSI data alongside local ecological and hydrological information is also presented and interpreted, to illustrate how improved understanding of biotic and abiotic relationships and interactions can be readily accomplished. Excessive fine-sediment accumulation on river beds results in impaired ecosystem health globally. The case studies and examples presented here will provide confidence that the PSI method can form the basis for evidence gathering and analysis, both within and beyond the United Kingdom. The paper concludes with an overview of the use of PSI in catchment research and management, a consideration of the relationship of the metric with other macroinvertebrate indices, and a summary of refinements recently applied to the index