scholarly journals Predicting Macroinvertebrate Responses to Water Abstraction in Alpine Streams

Water ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2121
Author(s):  
Gabriele Consoli ◽  
Fabio Lepori ◽  
Christopher T. Robinson ◽  
Andreas Bruder
Keyword(s):  
Habitat Model ◽  
Feeding Guilds ◽  
Physical Habitat ◽  
Macroinvertebrate Communities ◽  
Indirect Measure ◽  
Water Abstraction ◽  
Habitat Template ◽  
Hydropower Potential ◽  
Hydraulic Conditions ◽  
Alpine Streams

Exploitation of hydropower potential in alpine areas undermines the ecological integrity of rivers. Damming and water abstraction substantially alter the physical habitat template of rivers, with strong repercussions on aquatic communities and their resources. Tools are needed to predict and manage the consequences of these alterations on the structure and functioning of macroinvertebrate communities and resource availability in alpine streams. We developed habitat preference models for taxa, functional feeding guilds, and organic resources to quantify the effects of discharge alteration on macroinvertebrate communities in two alpine streams. Our physical habitat model related an indirect measure of bottom hydraulic forces (FST hemispheres) to the distribution of macroinvertebrate taxa and their resources. We observed that flow-dependent habitat availability for macroinvertebrate communities generally decreased with increasing water abstraction. We were able to relate these changes to near-bed hydraulic conditions. Our results suggest, however, the existence of upper discharge thresholds delimiting optimal habitat conditions for taxa. In contrast, we found weak effects of near-bed hydraulic conditions on resource distribution. Overall, our findings contribute towards predicting the impacts of water abstraction on macroinvertebrate communities in small alpine streams and the benefits of baseflow restoration.

From continua to patches: examining stream community structure over large environmental gradients

2002 ◽  
Vol 59 (8) ◽  
pp. 1404-1417 ◽  
Author(s):  
Kristopher K Wright ◽  
Judith L Li
Keyword(s):  
Conceptual Framework ◽  
Algal Biomass ◽  
Environmental Gradients ◽  
Spatial Scales ◽  
Habitat Characteristics ◽  
Physical Habitat ◽  
Macroinvertebrate Communities ◽  
Order Stream ◽  
Longitudinal Gradients ◽  
Individual Variables

We present an approach that integrates a conceptual framework with multivariate ordination techniques and traditional parametric analyses to examine biotic and abiotic gradients in stream ecosystems. Ordinations were used to examine multivariate patterns along an environmental gradient, with individual variables used to interpret those patterns across spatial scales. The conceptual framework provides a consistent context to compare community distributions and consequently allows for hypothesis testing using ordinations. To illustrate the approach, we examined the physical template, fish and benthic macroinvertebrate communities, and algal biomass and production along a 1st- through 5th-order stream gradient in eastern Oregon. We hypothesized that longitudinal distributions of physical habitat characteristics, fishes, macroinvertebrates, and periphyton would reflect highly variable, discontinuous gradients. Multivariate patterns were determined by rotating nonparametric ordinations to a common set of variables and comparing them to conceptual models of (i) an ideal continuum, (ii) a random distribution, and (iii) discrete patches. Physical habitat and fishes reflected strong longitudinal gradients, macroinvertebrates were the most patchy, and algal biomass and production were highly variable. Distributions of individual variables from site and stream-order perspectives revealed how different factors, potentially influencing stream communities, may be continuous or patchy depending on spatial scale.

Optimisation of a fuzzy physical habitat model for spawning European grayling (Thymallus thymallus L.) in the Aare river (Thun, Switzerland)

2008 ◽  
Vol 215 (1-3) ◽  
pp. 122-132 ◽  
Author(s):  
Ans M. Mouton ◽  
Matthias Schneider ◽  
Armin Peter ◽  
Georg Holzer ◽  
Rudolf Müller ◽  
...  
Keyword(s):  
Habitat Model ◽  
Physical Habitat ◽  
Thymallus Thymallus ◽  
European Grayling

scholarly journals Evaluation of By-Pass Fishway Operation for Attraction Efficiency Based on GPS Drifter Field Experiments

Water ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2302
Author(s):  
Kyong Oh Baek ◽  
Jeong Min Lee ◽  
Tae Geom Ku ◽  
Young Do Kim
Keyword(s):  
Fish Species ◽  
Flow Rate ◽  
Field Experiments ◽  
Main Channel ◽  
Spawning Season ◽  
Habitat Model ◽  
Rate Variation ◽  
Physical Habitat ◽  
Optimal Flow ◽  
Target Fish

The attraction efficiency of a by-pass fishway installed at Gangjeong-Goryeong Weir on the Nakdong River in South Korea was evaluated according to flow rate variation of the main channel. Optimal flow rate that achieved the maximum value of attraction efficiency at the fishway entrance was also determined. The weir can adjust the flow rate of the main channel and the fishway by operating sluice gates. The weighted usable area (WUA) calculated on the basis of habitat suitability criteria (HSC) for target species using River2D (a two-dimensional physical habitat model) was regarded as an indicator of attraction efficiency. The simulated velocity field by River2D was validated by virtue of measured data acquired from GPS drifter field experiments. Additionally, monthly fish monitoring data obtained with a fish trap served as supporting data to confirm the validity of the estimated attraction efficiency. The monitoring results revealed that the fishway attraction efficiency was the highest during the spawning season (from April to June). The target fish used the fishway most frequently in April. However, many other fish species used the fishway in June. Simulation results revealed that the flow rate of the main channel at the weir should be maintained at 190 m3/s in order to most effectively attract the target fish species into the fishway entrance. Managing the optimal flow rate by operating the sluice gate is especially important during the spawning season of the target fish to facilitate upstream and downstream migration.

scholarly journals Hydraulic considerations in restoring boreal streams

2004 ◽  
Vol 35 (3) ◽  
pp. 223-235 ◽  
Author(s):  
Juha Järvelä ◽  
Terhi Helmiö
Keyword(s):  
Flow Resistance ◽  
Field Studies ◽  
Physical Habitat ◽  
Cross Sectional ◽  
Success Criteria ◽  
Boreal Streams ◽  
Roughness Elements ◽  
Hydraulic Conditions ◽  
Two Factors ◽  
Small Channels

The physical habitat that controls ecosystem functioning is determined by local hydraulics and channel morphology. Hydraulic field studies were conducted in a boreal stream (1) to test the hypothesis that the local hydraulic conditions are determined by cross-sectional geometry and flow resistance in boreal conditions by analysing the relationship between flow velocities, cross-sectional geometry and flow resistance, and (2) to suggest success criteria for the restoration of local hydraulic conditions. Results suggest that, in the case of small channels, cross-sectional geometry and flow resistance are weakly interconnected and influenced by factors such as local roughness elements and channel forms. The study showed that both flow resistance and cross-sectional geometry are vital factors in determining local hydraulics. In stream restoration, a design based on consideration of only one of these two factors is inadequate and may result in a failure to replicate natural hydraulic conditions. Simple success criteria for the restoration of local hydraulics are developed.

scholarly journals Effects of an atypical drought on the benthic macroinvertebrate community in a tropical reservoir

2018 ◽  
Vol 18 (2) ◽  
Author(s):  
Maria José Pinheiro Anacléto ◽  
Raphael Ligeiro ◽  
José Etham de Lucena Barbosa ◽  
Joseline Molozzi ◽  
Marcos Callisto
Keyword(s):  
Community Structure ◽  
Exotic Species ◽  
Large Scale ◽  
Local Scale ◽  
Benthic Macroinvertebrate ◽  
Drought Event ◽  
Physical Habitat ◽  
Macroinvertebrate Communities ◽  
Disturbance Index ◽  
Structure Metrics

Abstract Atypical drought events have increasingly occurred in Brazil over the last years due to global climate changes. However, their consequences on aquatic biota in reservoirs are poorly known. We tested the hypothesis that macroinvertebrate communities are negatively affected by atypical drought events, given the sensitivity of many taxa to environmental changes. We predicted that: (a) there would be changes in limnological and sediment parameters between a regular year and an atypical year, (b) abundance and richness of the genera of Chironomidae and of exotic species would be higher due to the enhanced ability of these organisms to adapt to changes in the physical environment, and (c) community structure metrics (i. richness; ii. % richness; iii. abundance; iv. % abundance) would be affected by disturbance indices (i. Buffer Disturbance Index-BDI; ii. Local Disturbance Index-LDI; iii. Integrated Disturbance Index-IDI) in both years. The study was carried out in the reservoir of the Nova Ponte Hydroelectric Power Plant, state of Minas Gerais, comparing two sampling periods: a regular climatological year (2010) and an atypical drought year (2014). A total of 40 sampling sites were defined along the shore of the reservoir, and types of land use in the surrounding area of each site were measured, as well as physical habitat conditions, sediments, and benthic macroinvertebrate communities. Sampling was performed at these sites in the end of the rainy season in both years. The intensity of anthropogenic modifications was assessed at local scale and in the areas (buffers) surrounding the sampling sites using quantitative disturbance indices. There were striking differences in limnological parameters and sediment characteristics between sampling periods. Taxonomic richness was significantly lower in the drought year. As opposed to our predictions, richness and abundance of Chironomidae and exotic species did not increase with the atypical drought event. Besides, most community structure metrics showed a significant relationship with disturbance indices only during the regular climatological year, thus indicating that the large-scale effects of water stress may override the conditions of local habitats and the surrounding landscape. Therefore, in addition to a correct political-environmental management of water resources at local-scale, which includes maintaining the water quality and the riparian and landscape integrity, addressing large-scale climate issues is required for the maintenance of the ecological integrity of tropical reservoirs.

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