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P D Armitage - One of the best experts on this subject based on the ideXlab platform.
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biological effects of fine sediment in the Lotic Environment
Environmental Management, 1997Co-Authors: Paul J Wood, P D ArmitageAbstract:Although sedimentation is a naturally occurring phenomenon in rivers, land-use changes have resulted in an increase in anthropogenically induced fine sediment deposition. Poorly managed agricultural practices, mineral extraction, and construction can result in an increase in suspended solids and sedimentation in rivers and streams, leading to a decline in habitat quality. The nature and origins of fine sediments in the Lotic Environment are reviewed in relation to channel and nonchannel sources and the impact of human activity. Fine sediment transport and deposition are outlined in relation to variations in streamflow and particle size characteristics. A holistic approach to the problems associated with fine sediment is outlined to aid in the identification of sediment sources, transport, and deposition processes in the river catchment. The multiple causes and deleterious impacts associated with fine sediments on riverine habitats, primary producers, macroinvertebrates, and fisheries are identified and reviewed to provide river managers with a guide to source material. The restoration of rivers with fine sediment problems are discussed in relation to a holistic management framework to aid in the planning and undertaking of mitigation measures within both the river channel and surrounding catchment area. The deleterious effects of high suspended solid loads and sedimentation on riverine habitats have been well documented (Berkman and Rabeni 1987, Carling and McCahon 1987). The terms fine sediment and sedimentation used herein describe sediments less than 2 mm in size, thus encompassing sand (,2000 to .62 μm), silt (,62 to .4 μm) and clay (,4 μm) (Chang 1988, Church and others 1987). Fine sediments in the water column increase turbidity, limit light penetration, and potentially reduce primary productivity with resultant impacts on the rest of the food chain (Davies-Colley and others 1992, Van Nieuwenhuyse and LaPerriere 1986). Sedimentation modifies the substrate by altering its surface conditions (Graham 1990) and the volume of fine sediment within the hyporheos (Richards and Bacon 1994). In extreme cases, fine sediments smother the entire riverbed, changing channel morphology (Doeg and Koehn 1994, Nuttall 1972, Wright and Berrie 1987), killing aquatic flora (Brookes 1986, Edwards 1969), clogging the interstices between substrate clasts, increasing invertebrate drift, and reducing the available habitat for benthic organisms (Petts 1984a, Richards and Bacon 1994, Schalchi 1992). This review aims to provide information on the causes and extent of sedimentation in the Lotic Environment and in particular the impact on riverine ecology. We aim to examine the whole range of sizes and types of sediment (inorganic and organic) that have been referred to as fine sediments or implicated in sedimentation studies. We recognize that the effects of different types of fine sediment and sedimentation will vary, and where possible distinctions will be made between them. By considering the river holistically (Figure 1) the generation and passage of fine sediment to the stream and its transport, deposition, and storage in the channel can be elucidated. This is important in terms of both natural and anthropogenically induced processes because the extent of sedimentation varies spatially and temporally. Individual rivers respond in different ways to both natural and human impacts according to their catchment characteristics, although the latter tends to accelerate natural processes. There is a need to recognize and identify the physiochemical effects of sedimentation and their impact on riverine biota before mitigation measures are implemented (Figure 1). Nature and Origins of Fine Sediment The characteristics of fine sediment in rivers at a global scale are highly variable, reflecting variations in climate, catchment geology, basin scale, and sediment
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Biological Effects of Fine Sediment in the Lotic Environment
Environmental management, 1997Co-Authors: Paul J Wood, P D ArmitageAbstract:/ Although sedimentation is a naturally occurring phenomenon inrivers, land-use changes have resulted in an increase in anthropogenicallyinduced fine sediment deposition. Poorly managed agricultural practices,mineral extraction, and construction can result in an increase in suspendedsolids and sedimentation in rivers and streams, leading to a decline inhabitat quality. The nature and origins of fine sediments in the LoticEnvironment are reviewed in relation to channel and nonchannel sources andthe impact of human activity. Fine sediment transport and deposition areoutlined in relation to variations in streamflow and particle sizecharacteristics. A holistic approach to the problems associated with finesediment is outlined to aid in the identification of sediment sources,transport, and deposition processes in the river catchment. The multiplecauses and deleterious impacts associated with fine sediments on riverinehabitats, primary producers, macroinvertebrates, and fisheries are identifiedand reviewed to provide river managers with a guide to source material. Therestoration of rivers with fine sediment problems are discussed in relationto a holistic management framework to aid in the planning and undertaking ofmitigation measures within both the river channel and surrounding catchmentarea.KEY WORDS: Sedimentation; Fine sediment; Holistic approach; Ecologicalimpact; River restoration
Michael M Mcglue - One of the best experts on this subject based on the ideXlab platform.
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sponge spicules indicate holocene Environmental changes on the nabileque river floodplain southern pantanal brazil
Journal of Paleolimnology, 2013Co-Authors: Sidney Kuerten, Mauro Parolin, Mario Luis Assine, Michael M McglueAbstract:Sponge spicules are siliceous microfossils that are especially useful for analysis of sandy fluvio-lacustrine sediments. Sponge spicules in a long sediment core (~550 cm below surface), consisting of fine sand, sandy silt, and organic-rich mud, recovered from the floodplain of the Nabileque River, southern Pantanal, Brazil (S20°16′38.3″/W57°33′00.0″), form the basis of a novel paleoEnvironmental interpretation for this region. Optically stimulated luminescence dates constrain the timing of deposition to the middle-late Holocene and all spicules identified are typical of the Brazilian cerrado biome. The base of the section is dominated by Oncosclera navicella Carter 1881, Metania spinata Carter 1881, and Corvospongilla seckti Bonetto and Ezcurra de Drago 1966, which indicate a Lotic to semi-Lotic Environment strongly influenced by an actively meandering river channel at ~6.7–5.7 ka BP. The appearance of Heterorotula fistula Volkmer-Ribeiro and Motta 1995, Dosilia pydanieli Volkmer-Ribeiro 1992 and Radiospongilla amazonensis Volkmer-Ribeiro and Maciel 1983 at ~340 cm downcore suggests a reduction in flowing water and a more stable lentic Environment, consistent with deposition in an oxbow lake. This oxbow lake Environment existed during an interval of regional aridity between ~4.5 and 3.9 ka BP. Spicules, as well as phytoliths and diatoms, are highly variable moving up-section, with species from both Lotic and lentic ecosystems present. Above ~193 cm, the total abundance of spicules declines, consistent with wetter climate conditions and development of an underfit river similar to the modern floodplain. Results support hypotheses related to migration of the Paraguay River inferred from geomorphological studies and add a key southern-region dataset to the emerging Holocene database of paleoEnvironmental records from the Pantanal wetlands.
Paul J Wood - One of the best experts on this subject based on the ideXlab platform.
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biological effects of fine sediment in the Lotic Environment
Environmental Management, 1997Co-Authors: Paul J Wood, P D ArmitageAbstract:Although sedimentation is a naturally occurring phenomenon in rivers, land-use changes have resulted in an increase in anthropogenically induced fine sediment deposition. Poorly managed agricultural practices, mineral extraction, and construction can result in an increase in suspended solids and sedimentation in rivers and streams, leading to a decline in habitat quality. The nature and origins of fine sediments in the Lotic Environment are reviewed in relation to channel and nonchannel sources and the impact of human activity. Fine sediment transport and deposition are outlined in relation to variations in streamflow and particle size characteristics. A holistic approach to the problems associated with fine sediment is outlined to aid in the identification of sediment sources, transport, and deposition processes in the river catchment. The multiple causes and deleterious impacts associated with fine sediments on riverine habitats, primary producers, macroinvertebrates, and fisheries are identified and reviewed to provide river managers with a guide to source material. The restoration of rivers with fine sediment problems are discussed in relation to a holistic management framework to aid in the planning and undertaking of mitigation measures within both the river channel and surrounding catchment area. The deleterious effects of high suspended solid loads and sedimentation on riverine habitats have been well documented (Berkman and Rabeni 1987, Carling and McCahon 1987). The terms fine sediment and sedimentation used herein describe sediments less than 2 mm in size, thus encompassing sand (,2000 to .62 μm), silt (,62 to .4 μm) and clay (,4 μm) (Chang 1988, Church and others 1987). Fine sediments in the water column increase turbidity, limit light penetration, and potentially reduce primary productivity with resultant impacts on the rest of the food chain (Davies-Colley and others 1992, Van Nieuwenhuyse and LaPerriere 1986). Sedimentation modifies the substrate by altering its surface conditions (Graham 1990) and the volume of fine sediment within the hyporheos (Richards and Bacon 1994). In extreme cases, fine sediments smother the entire riverbed, changing channel morphology (Doeg and Koehn 1994, Nuttall 1972, Wright and Berrie 1987), killing aquatic flora (Brookes 1986, Edwards 1969), clogging the interstices between substrate clasts, increasing invertebrate drift, and reducing the available habitat for benthic organisms (Petts 1984a, Richards and Bacon 1994, Schalchi 1992). This review aims to provide information on the causes and extent of sedimentation in the Lotic Environment and in particular the impact on riverine ecology. We aim to examine the whole range of sizes and types of sediment (inorganic and organic) that have been referred to as fine sediments or implicated in sedimentation studies. We recognize that the effects of different types of fine sediment and sedimentation will vary, and where possible distinctions will be made between them. By considering the river holistically (Figure 1) the generation and passage of fine sediment to the stream and its transport, deposition, and storage in the channel can be elucidated. This is important in terms of both natural and anthropogenically induced processes because the extent of sedimentation varies spatially and temporally. Individual rivers respond in different ways to both natural and human impacts according to their catchment characteristics, although the latter tends to accelerate natural processes. There is a need to recognize and identify the physiochemical effects of sedimentation and their impact on riverine biota before mitigation measures are implemented (Figure 1). Nature and Origins of Fine Sediment The characteristics of fine sediment in rivers at a global scale are highly variable, reflecting variations in climate, catchment geology, basin scale, and sediment
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Biological Effects of Fine Sediment in the Lotic Environment
Environmental management, 1997Co-Authors: Paul J Wood, P D ArmitageAbstract:/ Although sedimentation is a naturally occurring phenomenon inrivers, land-use changes have resulted in an increase in anthropogenicallyinduced fine sediment deposition. Poorly managed agricultural practices,mineral extraction, and construction can result in an increase in suspendedsolids and sedimentation in rivers and streams, leading to a decline inhabitat quality. The nature and origins of fine sediments in the LoticEnvironment are reviewed in relation to channel and nonchannel sources andthe impact of human activity. Fine sediment transport and deposition areoutlined in relation to variations in streamflow and particle sizecharacteristics. A holistic approach to the problems associated with finesediment is outlined to aid in the identification of sediment sources,transport, and deposition processes in the river catchment. The multiplecauses and deleterious impacts associated with fine sediments on riverinehabitats, primary producers, macroinvertebrates, and fisheries are identifiedand reviewed to provide river managers with a guide to source material. Therestoration of rivers with fine sediment problems are discussed in relationto a holistic management framework to aid in the planning and undertaking ofmitigation measures within both the river channel and surrounding catchmentarea.KEY WORDS: Sedimentation; Fine sediment; Holistic approach; Ecologicalimpact; River restoration
Katrine Turgeon - One of the best experts on this subject based on the ideXlab platform.
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dams have varying impacts on fish communities across latitudes a quantitative synthesis
Ecology Letters, 2019Co-Authors: Katrine Turgeon, Christian Turpin, Irene GregoryeavesAbstract:Dams are recognised to impact aquatic biodiversity, but the effects and conclusions diverge across studies and locations. By using a meta-analytical approach, we quantified the effects of impoundment on fish communities distributed across three large biomes. The impacts of dams on richness and diversity differed across biomes, with significant declines in the tropics, lower amplitude but similar directional changes in temperate regions, and no changes in boreal regions. Our analyses showed that non-native species increased significantly in tropical and temperate regulated rivers, but not in boreal rivers. In contrast, temporal trajectories in fish assemblage metrics were common across regions, with all biomes showing an increase in mean trophic level position and in the proportion of generalist species after impoundment. Such changes in fish assemblages may affect food web stability and merit closer study. Across the literature examined, predominant mechanisms that render fish assemblages susceptible to impacts from dams were: (1) the transformation of the Lotic Environment into a lentic Environment; (2) habitat fragmentation and (3) the introduction of non-native species. Collectively, our results highlight that an understanding of the regional context and a suite of community metrics are needed to make robust predictions about how fish will respond to river impoundments.
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dams have varying impacts on fish communities across latitudes a quantitative synthesis
bioRxiv, 2018Co-Authors: Katrine Turgeon, Christian Turpin, Irene GregoryeavesAbstract:Dams are recognized to impact aquatic biodiversity and ecosystem functions, but the magnitude of effects vary across studies. By using a meta-analytical approach, we examined the effects of impoundment on fish community across three large biomes. The impacts of dams on richness and diversity differed across biomes, with significant declines in the tropics, lower amplitude but similar directional changes in temperate reservoirs, and no changes in boreal reservoirs. Our analysis also showed that non-native species increased significantly in tropical and temperate reservoirs, but not in boreal reservoirs. In contrast, temporal trajectories in fish assemblage metrics were common across regions, with all biomes showing an increase in mean trophic position and in the proportion of generalist species after impoundment. Such changes in fish assemblages may affect food web stability and merit closer study. Across the literature examined, predominant factors or mechanisms that render fish assemblages susceptible to impacts from dams were: 1) the transformation of the Lotic Environment into a lentic Environment; 2) habitat fragmentation and 3) invasive or non-native species. Collectively our results highlight that an understanding of the regional context and a suite of metrics are needed to make robust predictions about how fish will respond to river impoundments.
Julio Cesar Garavello - One of the best experts on this subject based on the ideXlab platform.
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fish assemblage structure of the ipanema river a small Lotic Environment partially protected by a conservation unit in southeastern brazil
Brazilian Journal of Biology, 2013Co-Authors: Alexandre Kannebley De Oliveira, Fernando Apone, José L. O. Birindelli, Julio Cesar GaravelloAbstract:A study on the fish assemblage of the Ipanema River, a small affluent of the Tiete River basin in southeastern Brazil, was performed aiming to look for structural patterns of species diversity in small lowland Lotic Environments. Fish samplings were performed every two months from June 2003 to April 2004 at four sample sites located on the lower stretch of the river. Local assemblage showed to be species rich, with fifty-two species belonging to Characiformes (25 spp.), Siluriformes (19 spp.), Cyprinodontiformes (3 spp.), Gymnotiformes (2 spp.), Perciformes (2 spp.), and Synbranchiformes (1 sp.). Fish fauna was composed of small-sized species (<200 mm SL) and by individuals of medium (up to 400 mm SL) to large (more than 400 mm SL) sized species. The Ipanema River, such as other small Lotic transitional Environments in the upper Parana River drainage, is considered important for conservation of fish fauna because they cover available habitats for persistent populations of small-sized species and for non-persistent individuals or shoals of medium and large-sized fish species, which occupy other habitats along their life-history (e. g. floodplains, oxbow lakes, main channel of great rivers). The importance of the Ipanema River basin for fish fauna conservation is also reinforced by the fact that it is located in a highly impacted region of southeastern Brazil, near the Sao Paulo metropolitan area.
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Fish assemblage structure of the Ipanema River, a small Lotic Environment partially protected by a Conservation Unit in southeastern Brazil
Brazilian journal of biology = Revista brasleira de biologia, 2013Co-Authors: Alexandre Kannebley De Oliveira, Fernando Apone, José L. O. Birindelli, Julio Cesar GaravelloAbstract:A study on the fish assemblage of the Ipanema River, a small affluent of the Tiete River basin in southeastern Brazil, was performed aiming to look for structural patterns of species diversity in small lowland Lotic Environments. Fish samplings were performed every two months from June 2003 to April 2004 at four sample sites located on the lower stretch of the river. Local assemblage showed to be species rich, with fifty-two species belonging to Characiformes (25 spp.), Siluriformes (19 spp.), Cyprinodontiformes (3 spp.), Gymnotiformes (2 spp.), Perciformes (2 spp.), and Synbranchiformes (1 sp.). Fish fauna was composed of small-sized species (
