Ecological degradation of a meandering river by local channelization effects: a case study in an Austrian lowland river

Graf, Wolfram; Leitner, Patrick; Hanetseder, I.; Ittner, L. D.; Dossi, Florian; Hauer, Christoph

doi:10.1007/s10750-016-2653-6

Cited by 40 publications

(20 citation statements)

References 60 publications

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“…In the Caet e river, abundances of the few dominant taxa in the meander thalweg were similar to those of the more diverse and equitable assemblages in the meander margin (Graf et al, 2016) and, differently to what was predicted, there was no difference in macroinvertebrate abundance between meander zones. Although we did not identify macroinvertebrates to species level, we found macroinvertebrate families that are indicators of each meander zone in the Caet e river.…”

Section: Greater Macroinvertebrate Diversity In Meander Flow Refugesmentioning

confidence: 47%

“…Although we did not identify macroinvertebrates to species level, we found macroinvertebrate families that are indicators of each meander zone in the Caet e river. Similarly, Graf et al (2016) found that Chironomidae dominated the assemblage and showed a preference for sandy substrates in an Austrian lowland river. Similarly, Graf et al (2016) found that Chironomidae dominated the assemblage and showed a preference for sandy substrates in an Austrian lowland river.…”

Section: Greater Macroinvertebrate Diversity In Meander Flow Refugesmentioning

confidence: 77%

“…In the meander thalweg, Chironomidae and Elmidae were dominant, their abundance being distributed among a low number of taxa (Legendre & Legendre, 2012). Similarly, Graf et al (2016) found that Chironomidae dominated the assemblage and showed a preference for sandy substrates in an Austrian lowland river. Some taxa are adapted to unstable substrates with strong flow, for example, members of the beetle family Elmidae, which have rigid elytra that resist the impact of sand grains moving in the current, and Chironomidae, which have structures for attachment to the substrate (Hamada et al, 2014).…”

Section: Greater Macroinvertebrate Diversity In Meander Flow Refugesmentioning

confidence: 77%

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Greater macroinvertebrate diversity and freshwater mussel density in meander margins of an Amazon river

et al. 2018

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Meanders are complex aquatic environments exhibiting different flow and sediment characteristics that influence macroinvertebrate distribution. Differences in macroinvertebrate composition, freshwater mussel density (mainly Castalia ambigua Lamarck, 1819) and habitat variables were investigated, using uni‐ and multivariate analyses, in two zones, the margin and thalweg, of the meanders of a 7‐km stretch of a morphologically unaltered tropical alluvial lowland river. Clear differences were found between meander zones, with greater taxonomic and functional diversity of macroinvertebrates and greater freshwater mussel densities in the meander margin. A total of 12 families of macroinvertebrates were exclusive to the meander margin, and macroinvertebrate indicators of zones were Philopotamidae and Leptoceridae (meander margin) and Chironomidae and Elmidae (meander thalweg). In the meander margin, there were no differences in macroinvertebrate abundance, and taxonomic and functional group diversity among areas with low, medium and high mussel density. Macroinvertebrate abundance did not vary between zones, but in both, abundance was associated with lower pH and higher electrical conductivity. Low shear velocity, which stabilises the river bed, high organic matter content and percentage silt in the meander margin were associated with higher taxonomic and functional macroinvertebrate diversity, as well as the presence of freshwater mussels. Natural unaltered meanders are spatially heterogeneous in both habitat and biodiversity and, similar to restored meanders, support greater macroinvertebrate taxonomic and functional diversity, as well as maintain freshwater mussel beds, mainly by stabilising the river bed. The meander margin may also be important for attracting mussel host fish that feed on macroinvertebrates and aid mussel dispersal. Thus, the meander margins, and other similar riparian habitats with low shear velocity, for example, side channels and pools, have potentially high conservation value and should be afforded due protection.

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Section: Greater Macroinvertebrate Diversity In Meander Flow Refugesmentioning

confidence: 47%

Section: Greater Macroinvertebrate Diversity In Meander Flow Refugesmentioning

confidence: 77%

Section: Greater Macroinvertebrate Diversity In Meander Flow Refugesmentioning

confidence: 77%

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Greater macroinvertebrate diversity and freshwater mussel density in meander margins of an Amazon river

et al. 2018

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“…Only site G showed comparable substrate conditions and corresponding results to the above-mentioned studies. Even though the overall species composition and density (lithal and xylal combined) showed no considerable differences to adjacent sites, siltation lead to major colonization disparities amongst the substrate types (Graf et al, 2016a). Benthic invertebrate density and diversity on xylal was approximately twice as high compared to surrounding sand habitats.…”

Section: Discussionmentioning

confidence: 85%

In the mood for wood-habitat specific colonization patterns of benthic invertebrate communities along the longitudinal gradient of an Austrian river

et al. 2017

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Instream large wood (LW) constitutes an indispensable element of natural river ecosystems. It affects local hydraulics, morphology, nutrient budget, overall habitat complexity, and dynamics. Despite numerous studies about LW as a habitat for benthic communities, information on the varying importance along the longitudinal gradient of a river is lacking. The focus of this study is therefore to investigate general differences between lithal and xylal colonizers and to further investigate trends along the river course. We analyzed lithal and xylal communities at ten sites along the medium-sized Lafnitz River in Southeast Austria. Our results significantly show (1) a general differentiation between lithal and xylal communities, (2) an increasing distinction of the lithal and xylal fauna along the longitudinal gradient of the river, and (3) a distinct correlation between the distance from source and the number of exclusive xylal and nowadays predominantly rare taxa. The presence of LW is therefore directly linked to higher aquatic biodiversity compared to rocky substrates and presents a unique element for river restoration, especially in lower river sections.

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“…In particular, the morphodynamics of ripples (e.g., Carling, Williams, Golz, & Kelsey, ) are of great importance, as they are responsible for the low abundance of macroinvertebrates in the area of interest (Leitner et al, ). Various macroinvertebrate species have adapted to coarse sand and fine gravel (e.g., Cironomidae and Oligocheten ; Graf et al, ) but not to high mobile bedforms. However, in contrast to the idealized boundary conditions in physical laboratory studies (e.g., Baas, ), the ripple movements in studied granite/gneiss rivers have been found to be variable, partially in terms of the coarse surface layer grains of the characteristic bimodal grain‐size distribution (cf.…”

Section: Introductionmentioning

confidence: 99%

Ripple dynamics over various microtopographical roughness elements and their implications for river management

Hauer

Lichtneger

Holzinger

et al. 2019

River Research & Apps

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Specific problems in connection with the sediment regime have arisen in the granite and gneiss area in the northern part of Austria due to the increased sediment supply of coarse sand and fine gravel as a product of rock weathering. One of the physical characteristics of these sediments is their high mobility in form of ripple bedforms along the surface. In these rivers, the microtopographical structures of the bed surface are hydraulically active, especially in the initial stages when ripples have not overtopped the largest elements of the bed's roughness elements. There is a lack of detailed studies of the impacts of these microtopographical structures on ripple dynamics. Thus, the aim of the present study was to investigate the impact of various microtopographic roughness elements on ripple movement. This study was performed using a 1:1-scaled physical laboratory experiment. The results showed, in all repetitions of the experiment with variable grain sizes, that the higher the microtopographical variability of the river substrate and turbulence was, the higher the measured transport velocities of the ripples were. The expected hidden impacts on sediment transport were not documented. Important implications for sediment management were discussed, as river sections with high accumulation rates of coarse sand and fine gravel are prone to additional degradation as downstream transport decreases over smooth ripple-dune morphologies. Additionally, structural elements such as exposed rocks may increase the downstream transport due to the increased variability in turbulence.

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Ecological degradation of a meandering river by local channelization effects: a case study in an Austrian lowland river

Cited by 40 publications

References 60 publications

Greater macroinvertebrate diversity and freshwater mussel density in meander margins of an Amazon river

Greater macroinvertebrate diversity and freshwater mussel density in meander margins of an Amazon river

In the mood for wood-habitat specific colonization patterns of benthic invertebrate communities along the longitudinal gradient of an Austrian river

Ripple dynamics over various microtopographical roughness elements and their implications for river management

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