Pub Date : 2021-06-15DOI: 10.1080/24705357.2021.1892547
Chendi Zhang, Mengzhen Xu, F. Lei, Jiahao Zhang, G. Kattel, Yongjie Duan
Abstract The naked carp (Gymnocypris przewalskii) plays a central role in the ecosystem of the Qinghai Lake, the largest saline-alkaline lake in China. The adult naked carp migrates in large groups with high population density annually from the Qinghai Lake to the upstream freshwater rivers to spawn. Nevertheless, the responsiveness of the fish to local abiotic cues in the form of distribution patterns during migration across the riverine-lacustrine network of the Qinghai Lake region remains unknown. This knowledge gap has reduced efficiency in fish conservation and management efforts in the region. To address this issue, we carried out two field surveys from June to August, 2018, with the aid of unmanned aerial vehicles to a 200-m long back channel characterizing diverse morphological and hydraulic features on the migration route. Combined structure from motion photogrammetry and deep neural network techniques were used to establish a new workflow for detecting and extracting the profiles of fish individuals in large schools. The spatio-temporal distribution pattern of the fish demonstrated that the naked carp was attracted by hydraulic environments with high flow velocity or deep-water during migration. The diurnal variation of temperature and light could alter the preference for hydraulic environments of the fish. Our results highlight the crucial role of the interactions between river morphology and hydraulics, water temperature and light on the migration behaviours of the naked carp.
{"title":"Spatio-temporal distribution of Gymnocypris przewalskii during migration with UAV-based photogrammetry and deep neural network","authors":"Chendi Zhang, Mengzhen Xu, F. Lei, Jiahao Zhang, G. Kattel, Yongjie Duan","doi":"10.1080/24705357.2021.1892547","DOIUrl":"https://doi.org/10.1080/24705357.2021.1892547","url":null,"abstract":"Abstract The naked carp (Gymnocypris przewalskii) plays a central role in the ecosystem of the Qinghai Lake, the largest saline-alkaline lake in China. The adult naked carp migrates in large groups with high population density annually from the Qinghai Lake to the upstream freshwater rivers to spawn. Nevertheless, the responsiveness of the fish to local abiotic cues in the form of distribution patterns during migration across the riverine-lacustrine network of the Qinghai Lake region remains unknown. This knowledge gap has reduced efficiency in fish conservation and management efforts in the region. To address this issue, we carried out two field surveys from June to August, 2018, with the aid of unmanned aerial vehicles to a 200-m long back channel characterizing diverse morphological and hydraulic features on the migration route. Combined structure from motion photogrammetry and deep neural network techniques were used to establish a new workflow for detecting and extracting the profiles of fish individuals in large schools. The spatio-temporal distribution pattern of the fish demonstrated that the naked carp was attracted by hydraulic environments with high flow velocity or deep-water during migration. The diurnal variation of temperature and light could alter the preference for hydraulic environments of the fish. Our results highlight the crucial role of the interactions between river morphology and hydraulics, water temperature and light on the migration behaviours of the naked carp.","PeriodicalId":93201,"journal":{"name":"Journal of ecohydraulics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87409403","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-05-13DOI: 10.1080/24705357.2020.1869916
Márcio S. Roth, Ch. Jähnel, J. Stamm, L. Schneider
Abstract Fishways are an important link for the reestablishment of river continuity, interrupted by transverse structures e.g. weirs, dams and hydropower plants. The meander fishway and vertical slot fishway are two types commonly constructed in Germany, which create distinctive flow regimes to allow upstream passage. Nonetheless minor environmental or constructional alterations create unforeseen flow regimes, whose impact on fish behaviour is still uncertain. One approach is to obtain different flow aspects for fish by evaluating numerous parameters with the IPOS-framework in laboratory experiments. The framework provides various identification parameters and methods, which must be considered with regard to fish behaviour. This paper expands the experimental approach by using numerical simulations with OpenFOAM on one meander and two vertical slot fishways and employs the evaluation methods stated in the IPOS-framework. The results shows clear differences between the fishways, providing an advanced numerical evaluation method to objectively compare turbulent flows in the models. The 3D-hydronumerical evaluation of 1:1 scaled fishways using the IPOS-framework is a novelty so far and can be used to improve present and future fishway constructions.
{"title":"Turbulent eddy identification of a meander and vertical-slot fishways in numerical models applying the IPOS-framework","authors":"Márcio S. Roth, Ch. Jähnel, J. Stamm, L. Schneider","doi":"10.1080/24705357.2020.1869916","DOIUrl":"https://doi.org/10.1080/24705357.2020.1869916","url":null,"abstract":"Abstract Fishways are an important link for the reestablishment of river continuity, interrupted by transverse structures e.g. weirs, dams and hydropower plants. The meander fishway and vertical slot fishway are two types commonly constructed in Germany, which create distinctive flow regimes to allow upstream passage. Nonetheless minor environmental or constructional alterations create unforeseen flow regimes, whose impact on fish behaviour is still uncertain. One approach is to obtain different flow aspects for fish by evaluating numerous parameters with the IPOS-framework in laboratory experiments. The framework provides various identification parameters and methods, which must be considered with regard to fish behaviour. This paper expands the experimental approach by using numerical simulations with OpenFOAM on one meander and two vertical slot fishways and employs the evaluation methods stated in the IPOS-framework. The results shows clear differences between the fishways, providing an advanced numerical evaluation method to objectively compare turbulent flows in the models. The 3D-hydronumerical evaluation of 1:1 scaled fishways using the IPOS-framework is a novelty so far and can be used to improve present and future fishway constructions.","PeriodicalId":93201,"journal":{"name":"Journal of ecohydraulics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90696346","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-03-28DOI: 10.1080/24705357.2020.1820913
J. Ramos, J. Gracia-Sánchez, L. Marrufo-Vázquez
Abstract Mangrove lands are becoming livestock and agriculture systems generating a reduction in estuary areas and an increase in the sediments transported towards the sea. This situation is prevalent in Marismas Nacionales, estuary of the San Pedro-Mezquital River, Mexico. Using satellite imaging, the deforestation rate for both forest and mangrove, as well as the morphologic change of the river and its floodplain were estimated. Remote sensing techniques were applied to achieve an integrated analysis of land change. The loss of forest was around 30% from the 80’s to the 90’s, and was more severe and constant in the middle of the basin. In this area, results show that the sediment increase directly affects water bodies and mangroves downstream, showing a decrease of 30% and 20%, respectively. The main land change was the conversion into agricultural areas, which affected coastal lands with large changes in sediment size and quality. The latter is due to the residual amounts from the anthropogenic economicactivities which form great water-stable aggregates by modifying the mangroves soil characteristics. This change of soil properties is related to the loss of capability to maintain biotic communities, thus ecosystems die gradually. However, the ecosystem could recover with active human participation.
{"title":"Loss of mangroves as a consequence of the anthropic interactions downstream a river basin","authors":"J. Ramos, J. Gracia-Sánchez, L. Marrufo-Vázquez","doi":"10.1080/24705357.2020.1820913","DOIUrl":"https://doi.org/10.1080/24705357.2020.1820913","url":null,"abstract":"Abstract Mangrove lands are becoming livestock and agriculture systems generating a reduction in estuary areas and an increase in the sediments transported towards the sea. This situation is prevalent in Marismas Nacionales, estuary of the San Pedro-Mezquital River, Mexico. Using satellite imaging, the deforestation rate for both forest and mangrove, as well as the morphologic change of the river and its floodplain were estimated. Remote sensing techniques were applied to achieve an integrated analysis of land change. The loss of forest was around 30% from the 80’s to the 90’s, and was more severe and constant in the middle of the basin. In this area, results show that the sediment increase directly affects water bodies and mangroves downstream, showing a decrease of 30% and 20%, respectively. The main land change was the conversion into agricultural areas, which affected coastal lands with large changes in sediment size and quality. The latter is due to the residual amounts from the anthropogenic economicactivities which form great water-stable aggregates by modifying the mangroves soil characteristics. This change of soil properties is related to the loss of capability to maintain biotic communities, thus ecosystems die gradually. However, the ecosystem could recover with active human participation.","PeriodicalId":93201,"journal":{"name":"Journal of ecohydraulics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86779561","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-03-15DOI: 10.1080/24705357.2020.1856008
A. Barillier, L. Bêche, J. Malavoi, V. Gouraud
Abstract Downstream of hydroelectric plants, hydropeaking can cause frequent flow variations, resulting in habitat modifications (e.g. hydraulics, reach morphology, temperature, water quality), which can impact organisms (stranding, dewatering, forced drift, growth disturbances) and ultimately may have negative and lasting impacts on biological communities, reducing resilience. Nevertheless, the severity of habitat disturbances vary depending on other existing pressures and local site conditions, which need to be taken into account to achieve effective hydropeaking mitigation. Preserving hydropower flexibility is also a priority to ensure the stability of electric systems without recourse to more polluting alternatives. Given these apparently opposing objectives, we propose a consensual technico-economic framework to guarantee the feasibility and effectiveness of site-specific hydropeaking mitigation, based on our experience as a hydropower operator and a literature review. While existing tools (such as habitat models) can be used to predict expected local effects of proposed mitigation and compare scenarios, predicting biological community responses is not currently possible (lack of in-situ evaluations of mitigation efficacy). These uncertainties and complex socio-ecosystems necessitate a forward-looking global approach that accounts for climate change, multi-purpose water use and electric system requirements, combined with site-specific analyses of the relative importance of hydropeaking impacts with respect to other pressures.
{"title":"Identification of effective hydropeaking mitigation measures: are hydraulic habitat models sufficient in a global approach?","authors":"A. Barillier, L. Bêche, J. Malavoi, V. Gouraud","doi":"10.1080/24705357.2020.1856008","DOIUrl":"https://doi.org/10.1080/24705357.2020.1856008","url":null,"abstract":"Abstract Downstream of hydroelectric plants, hydropeaking can cause frequent flow variations, resulting in habitat modifications (e.g. hydraulics, reach morphology, temperature, water quality), which can impact organisms (stranding, dewatering, forced drift, growth disturbances) and ultimately may have negative and lasting impacts on biological communities, reducing resilience. Nevertheless, the severity of habitat disturbances vary depending on other existing pressures and local site conditions, which need to be taken into account to achieve effective hydropeaking mitigation. Preserving hydropower flexibility is also a priority to ensure the stability of electric systems without recourse to more polluting alternatives. Given these apparently opposing objectives, we propose a consensual technico-economic framework to guarantee the feasibility and effectiveness of site-specific hydropeaking mitigation, based on our experience as a hydropower operator and a literature review. While existing tools (such as habitat models) can be used to predict expected local effects of proposed mitigation and compare scenarios, predicting biological community responses is not currently possible (lack of in-situ evaluations of mitigation efficacy). These uncertainties and complex socio-ecosystems necessitate a forward-looking global approach that accounts for climate change, multi-purpose water use and electric system requirements, combined with site-specific analyses of the relative importance of hydropeaking impacts with respect to other pressures.","PeriodicalId":93201,"journal":{"name":"Journal of ecohydraulics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84447391","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-03-02DOI: 10.1080/24705357.2020.1839799
I. Jowett, J. Hayes, Jason R. Neuswanger
Abstract Software is now available to apply a salmonid bioenergetic drift-foraging model to generate values of net energy intake (NEI) over a range of water depths and velocities. The predictions can be used to build univariate “habitat” suitability curves or multivariate “habitat” selection models for use in instream habitat modelling programs. Capture success and swimming cost sub-models are basic components of the bioenergetic model and there is a need to understand their influence of NEI predictions. Examination of the swimming cost sub-models showed a surprising amount of variation between species and models and this was attributed to the amount and range of data used for their derivation and the different methods of formulating the swimming cost equations. Predictions of optimal velocity for large fish (>96 g) was influenced by the choice of swimming cost sub-model but optimal velocities for smaller fish were dependent on the capture success sub-model. More research is needed to validate the capture success sub-model, especially for larger fish sizes. Swimming costs while intercepting prey, and the cost of swimming in natural streams with turbulence, are other factors that remain uncertain.
{"title":"Salmonid bioenergetic drift-foraging: swimming costs and capture success","authors":"I. Jowett, J. Hayes, Jason R. Neuswanger","doi":"10.1080/24705357.2020.1839799","DOIUrl":"https://doi.org/10.1080/24705357.2020.1839799","url":null,"abstract":"Abstract Software is now available to apply a salmonid bioenergetic drift-foraging model to generate values of net energy intake (NEI) over a range of water depths and velocities. The predictions can be used to build univariate “habitat” suitability curves or multivariate “habitat” selection models for use in instream habitat modelling programs. Capture success and swimming cost sub-models are basic components of the bioenergetic model and there is a need to understand their influence of NEI predictions. Examination of the swimming cost sub-models showed a surprising amount of variation between species and models and this was attributed to the amount and range of data used for their derivation and the different methods of formulating the swimming cost equations. Predictions of optimal velocity for large fish (>96 g) was influenced by the choice of swimming cost sub-model but optimal velocities for smaller fish were dependent on the capture success sub-model. More research is needed to validate the capture success sub-model, especially for larger fish sizes. Swimming costs while intercepting prey, and the cost of swimming in natural streams with turbulence, are other factors that remain uncertain.","PeriodicalId":93201,"journal":{"name":"Journal of ecohydraulics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76016339","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-02-09DOI: 10.1080/24705357.2020.1840313
J. Boudreault, A. St‐Hilaire, F. Chebana, N. Bergeron
Abstract In this paper, a new fish habitat modelling approach is introduced using the full probability density functions (PDF), rather than single measurements or central tendency metrics, to describe each predictor. To model habitat selection using PDFs, functional regression models (FRM) are used to allow for the inclusion of curves or functions (smoothed empirical PDFs) in regression models compared to scalars or vectors in classical contexts. The benefits of FRM are exemplified by comparing results with those obtained using generalized additive models (GAM), one of the most recent and performing models in the field. Abundance of juvenile Atlantic salmon sampled at 26 sites (75 m-long x river width) of the Sainte-Marguerite River (Quebec, Canada) was modelled with PDFs of four potential predictors: flow velocity, water depth, substrate size and water temperature. The latter has been less frequently used in habitat modelling and the results showed that it was the most significant predictor. Overall, FRM explained more of the variability in habitat selection than GAM (+14.9% for fry and +8.1% for 1+ parr), mainly due to their ability to use complete distributions of the habitat variables rather than aggregated values (mean). A leave-one-out cross validation showed that both GAM and FRM had similar performance to predict fish abundance. The use of FRM in fish habitat modelling is innovative and its potential should be further developed, especially in the current context where habitat variables are becoming increasingly easy to obtain due to rapid progress of remote measurement techniques.
{"title":"Modelling fish physico-thermal habitat selection using functional regression","authors":"J. Boudreault, A. St‐Hilaire, F. Chebana, N. Bergeron","doi":"10.1080/24705357.2020.1840313","DOIUrl":"https://doi.org/10.1080/24705357.2020.1840313","url":null,"abstract":"Abstract In this paper, a new fish habitat modelling approach is introduced using the full probability density functions (PDF), rather than single measurements or central tendency metrics, to describe each predictor. To model habitat selection using PDFs, functional regression models (FRM) are used to allow for the inclusion of curves or functions (smoothed empirical PDFs) in regression models compared to scalars or vectors in classical contexts. The benefits of FRM are exemplified by comparing results with those obtained using generalized additive models (GAM), one of the most recent and performing models in the field. Abundance of juvenile Atlantic salmon sampled at 26 sites (75 m-long x river width) of the Sainte-Marguerite River (Quebec, Canada) was modelled with PDFs of four potential predictors: flow velocity, water depth, substrate size and water temperature. The latter has been less frequently used in habitat modelling and the results showed that it was the most significant predictor. Overall, FRM explained more of the variability in habitat selection than GAM (+14.9% for fry and +8.1% for 1+ parr), mainly due to their ability to use complete distributions of the habitat variables rather than aggregated values (mean). A leave-one-out cross validation showed that both GAM and FRM had similar performance to predict fish abundance. The use of FRM in fish habitat modelling is innovative and its potential should be further developed, especially in the current context where habitat variables are becoming increasingly easy to obtain due to rapid progress of remote measurement techniques.","PeriodicalId":93201,"journal":{"name":"Journal of ecohydraulics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83779122","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-02-01DOI: 10.1080/24705357.2020.1831415
C. Rachelly, K. Mathers, C. Weber, V. Weitbrecht, R. Boes, D. Vetsch
Abstract Habitats that mitigate the effects of a disturbance event (e.g. flood) are referred to as refugia. Their occurrence in heavily impacted river systems is often limited, and their restoration rarely pursued. This paper presents the results of a combined laboratory and numerical modeling study to assess flood refugia availability to mobile aquatic organisms in the context of river restoration and dynamic river widening. We used a calibrated 2D hydrodynamic model based on eight topographies obtained in laboratory experiments to assess refugia availability by analyzing the hydro-morphological conditions under varying sediment supply. Overall, sediment equilibrium sustains more complex hydro-morphological conditions with low bed shear stress zones being maintained during elevated discharges. Furthermore, our results suggest that the floodplain is an important potential refuge that becomes accessible for discharges with a return period of approximately one year. Conversely, sediment deficit results in a homogeneous flow field with steadily increasing hydraulic forces for high flows and impaired lateral connectivity except for very large flood events of a 30- to 100-year return period. Dynamic river widening implemented in a channel with sediment equilibrium conditions as opposed to a sediment deficit is thus more likely to provide flood refugia.
{"title":"How does sediment supply influence refugia availability in river widenings?","authors":"C. Rachelly, K. Mathers, C. Weber, V. Weitbrecht, R. Boes, D. Vetsch","doi":"10.1080/24705357.2020.1831415","DOIUrl":"https://doi.org/10.1080/24705357.2020.1831415","url":null,"abstract":"Abstract Habitats that mitigate the effects of a disturbance event (e.g. flood) are referred to as refugia. Their occurrence in heavily impacted river systems is often limited, and their restoration rarely pursued. This paper presents the results of a combined laboratory and numerical modeling study to assess flood refugia availability to mobile aquatic organisms in the context of river restoration and dynamic river widening. We used a calibrated 2D hydrodynamic model based on eight topographies obtained in laboratory experiments to assess refugia availability by analyzing the hydro-morphological conditions under varying sediment supply. Overall, sediment equilibrium sustains more complex hydro-morphological conditions with low bed shear stress zones being maintained during elevated discharges. Furthermore, our results suggest that the floodplain is an important potential refuge that becomes accessible for discharges with a return period of approximately one year. Conversely, sediment deficit results in a homogeneous flow field with steadily increasing hydraulic forces for high flows and impaired lateral connectivity except for very large flood events of a 30- to 100-year return period. Dynamic river widening implemented in a channel with sediment equilibrium conditions as opposed to a sediment deficit is thus more likely to provide flood refugia.","PeriodicalId":93201,"journal":{"name":"Journal of ecohydraulics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84623649","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-17DOI: 10.1080/24705357.2020.1855086
Marcía N Snyder, Nathan H Schumaker, Jason B Dunham, Matthew L Keefer, Peter Leinenbach, Allen Brookes, John Palmer, Jennifer Wu, Druscilla Keenan, Joseph L Ebersole
Diadromous fish populations face multiple challenges along their migratory routes. These challenges include suboptimal water quality, harvest, and barriers to longitudinal and lateral connectivity. Interactions among factors influencing migration success make it challenging to assess management options for improving migratory fish conditions along riverine migration corridors. We describe a spatially explicit simulation model that integrates complex individual behaviors of fall-run Chinook Salmon (Oncorhynchus tshawytscha) and summer-run steelhead trout (O. mykiss) during migration, responds to variable habitat conditions over a large extent of the Columbia River, and links migration corridor conditions to fish condition outcomes. The model is built around a mechanistic behavioral decision tree that drives individual interactions of fish within their simulated environments. By simulating several thermalscapes with alternative scenarios of thermal refuge availability, we examined how behavioral thermoregulation in cold-water refuges influenced migrating fish conditions. Outcomes of the migration corridor simulation model show that cold-water refuges can provide relief from exposure to high water temperatures, but do not substantially contribute to energy conservation by migrating adults. Simulated cooling of the Columbia River decreased reliance on cold-water refuges and there were slight reductions in migratory energy expenditure. This modeling of simulated thermalscapes provides a framework for assessing the contribution of cold-water refuges to the success of migrating fishes, but any final determination will depend on analyzing fish survival and health for their entire migration, water temperature management goals and species recovery targets.
{"title":"Assessing contributions of cold-water refuges to reproductive migration corridor conditions for adult Chinook Salmon and steelhead trout in the Columbia River, USA.","authors":"Marcía N Snyder, Nathan H Schumaker, Jason B Dunham, Matthew L Keefer, Peter Leinenbach, Allen Brookes, John Palmer, Jennifer Wu, Druscilla Keenan, Joseph L Ebersole","doi":"10.1080/24705357.2020.1855086","DOIUrl":"https://doi.org/10.1080/24705357.2020.1855086","url":null,"abstract":"<p><p>Diadromous fish populations face multiple challenges along their migratory routes. These challenges include suboptimal water quality, harvest, and barriers to longitudinal and lateral connectivity. Interactions among factors influencing migration success make it challenging to assess management options for improving migratory fish conditions along riverine migration corridors. We describe a spatially explicit simulation model that integrates complex individual behaviors of fall-run Chinook Salmon (<i>Oncorhynchus tshawytscha</i>) and summer-run steelhead trout (<i>O. mykiss</i>) during migration, responds to variable habitat conditions over a large extent of the Columbia River, and links migration corridor conditions to fish condition outcomes. The model is built around a mechanistic behavioral decision tree that drives individual interactions of fish within their simulated environments. By simulating several thermalscapes with alternative scenarios of thermal refuge availability, we examined how behavioral thermoregulation in cold-water refuges influenced migrating fish conditions. Outcomes of the migration corridor simulation model show that cold-water refuges can provide relief from exposure to high water temperatures, but do not substantially contribute to energy conservation by migrating adults. Simulated cooling of the Columbia River decreased reliance on cold-water refuges and there were slight reductions in migratory energy expenditure. This modeling of simulated thermalscapes provides a framework for assessing the contribution of cold-water refuges to the success of migrating fishes, but any final determination will depend on analyzing fish survival and health for their entire migration, water temperature management goals and species recovery targets.</p>","PeriodicalId":93201,"journal":{"name":"Journal of ecohydraulics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/24705357.2020.1855086","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38908502","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-17DOI: 10.1080/24705357.2020.1858197
Jana Carus, C. Arndt, T. Bouma, B. Schröder, M. Paul
Abstract Seagrass meadows have disappeared on many coastal sections due to anthropogenic disturbances, diseases, and/or eutrophication. To facilitate informed seagrass restoration, we i) quantified the hydrodynamic dislodgement thresholds for newly transplanted Z. marina shoots, and ii) tested the effect of artificial seagrass (ASG) as a hydrodynamic protection measure. Experiments were carried out by planting Z. marina rhizomes with living shoots into a sediment bed and exposing them to a range of wave and current conditions in a flume. The use of ASG significantly reduced wave height, as well as current velocity. The applied waves led to the development of ripples whereas currents led to erosion of the sediment bed. The number of shoots that were uprooted and dislodged increased with increasing bed shear stress and erosion. By reducing bed shear stress, the ASG raised the input current velocity threshold, which the transplanted shoots were able to withstand. The present study offers insight into the effect of artificial seagrass (ASG) on wave and current attenuation, as well as sediment erosion and shoot dislodgement. Our results help to inform the setting of hydrodynamic thresholds for the early establishment of Z. marina and to define the improvement of hydrodynamic conditions by ASG.
{"title":"Effect of artificial seagrass on hydrodynamic thresholds for the early establishment of Zostera marina","authors":"Jana Carus, C. Arndt, T. Bouma, B. Schröder, M. Paul","doi":"10.1080/24705357.2020.1858197","DOIUrl":"https://doi.org/10.1080/24705357.2020.1858197","url":null,"abstract":"Abstract Seagrass meadows have disappeared on many coastal sections due to anthropogenic disturbances, diseases, and/or eutrophication. To facilitate informed seagrass restoration, we i) quantified the hydrodynamic dislodgement thresholds for newly transplanted Z. marina shoots, and ii) tested the effect of artificial seagrass (ASG) as a hydrodynamic protection measure. Experiments were carried out by planting Z. marina rhizomes with living shoots into a sediment bed and exposing them to a range of wave and current conditions in a flume. The use of ASG significantly reduced wave height, as well as current velocity. The applied waves led to the development of ripples whereas currents led to erosion of the sediment bed. The number of shoots that were uprooted and dislodged increased with increasing bed shear stress and erosion. By reducing bed shear stress, the ASG raised the input current velocity threshold, which the transplanted shoots were able to withstand. The present study offers insight into the effect of artificial seagrass (ASG) on wave and current attenuation, as well as sediment erosion and shoot dislodgement. Our results help to inform the setting of hydrodynamic thresholds for the early establishment of Z. marina and to define the improvement of hydrodynamic conditions by ASG.","PeriodicalId":93201,"journal":{"name":"Journal of ecohydraulics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79994693","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-17DOI: 10.1080/24705357.2020.1858724
M. Forcellini, L. Plichard, S. Dolédec, S. Mérigoux, J. Olivier, S. Cauvy‐Fraunié, N. Lamouroux
Abstract The transferability of hydraulic microhabitat selection models among rivers has been largely debated. It can influence management decisions such as restoration measures or environmental flow definitions. We updated microhabitat selection models for 258 macroinvertebrate taxa, with 141 species, collected in 2128 Surber or Hess samples during 91 surveys (sites × dates) distributed in eleven small streams to large rivers of Germany and France. We compared microhabitat selection for four hydraulic variables, developed using mixed-effects models that account for the overdispersion of observed abundance, partly due to spatial aggregation. Models based on bed shear stress, water column velocity and Froude number showed comparable results and were stronger than models for water depth. For these velocity-related variables, 61–78% of models were significant and revealed variable response forms among taxa. The explanatory power of “average” microhabitat selection models, with response forms common to all surveys, was 78–83% of the explanatory power of more detailed models with variable response forms. Significant associations with biological traits such as locomotion, relation to substrate or food types suggested that microhabitat selection results from general biological processes. Our results indicate a high degree of transferability and can be useful in many basic and applied ecological studies.
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