Dams: Ecological Impacts and Management

Schmutz, Stefan; Moog, Otto

doi:10.1007/978-3-319-73250-3_6

Cited by 100 publications

(69 citation statements)

References 25 publications

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“…By that, reaches immediately downstream of dams may show relatively elevated flow velocities and larger grain sizes of the substrate, which might benefit the native rheophylic, lithophylic species (e.g., Ebro barbel) rather than the limnophilic alien species (e.g., largemouth black bass [ Micropterus salmoides ]). With increasing distance from a dam, the likelihood of impounding effects (e.g., slower flow velocities and/or siltation, Schmutz & Moog, ) induced by the next downstream dam increases, which might additionally promote the abundance of limnophilic alien fishes. Similarly to previous findings (e.g., Murphy et al, ), variables related to the total of dams/barriers in the entire upstream catchment were also found relevant pointing to the cumulative effects of dams.…”

Section: Discussionmentioning

confidence: 99%

“…Similarly to previous findings (e.g., Murphy et al, ), variables related to the total of dams/barriers in the entire upstream catchment were also found relevant pointing to the cumulative effects of dams. Specifically, the sediment transport is severely altered by dams with approximately 25%–30% of the pre‐disturbance sediment flux being trapped in reservoirs globally (Schmutz & Moog, ). Cumulative effects of dams generally cause a deficit of coarse sediments, increased rates of sedimentation of smaller grain sizes and consequently decreased water turbidity (Schmutz & Moog, ), which benefits most alien and disfavours the native species in the Ebro River.…”

Section: Discussionmentioning

confidence: 99%

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Environmental filtering governs the spatial distribution of alien fishes in a large, human‐impacted Mediterranean river

Radinger

Alcaraz‐Hernández

García‐Berthou

2019

Diversity and Distributions

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Aim:To analyse the occurrence and abundance of native versus alien fish species in relation to climate, land use, hydrologic alteration and habitat fragmentation in a heavily invaded and human-impacted riverine ecosystem. To test whether co-occurrence patterns of native versus alien species are structured by environmental filtering or biotic associations.Location: Mediterranean, Iberian Peninsula, Ebro River catchment. Methods:We modelled freshwater fish distributions and their association with environmental conditions using a hurdle model-like approach involving boosted regression trees. Additionally, we applied a joint species distribution model to quantify the co-occurrence of native versus alien fish species that can be attributed to shared environmental responses or potentially to biotic interactions. Results:Our results point to environmental factors, rather than biotic associations, as major correlates of the increase of alien and the decline of native fishes in the Ebro River. We observed contrasting patterns of native versus alien species along the upstream-downstream gradient. Alien species dominated in the lower reaches associated with warmer temperatures, higher shares of intensive land use and appeared facilitated by dams and river regulation. Native species richness was highest in the larger tributaries followed by a strong decline in the main stem which was related to the river network position and land use type. Fragmentation played a subordinate role in explaining fish richness and abundance patterns.Main conclusions: Given the strong association with temperature, a further range expansion of alien fishes in the Ebro with future climate change may be expected.More local-scale factors related to habitat degradation and hydrologic alteration will further exacerbate the invasion success of many alien fishes. Further multiple, independent species introductions might mask isolation and fragmentation effects of dams on the future spread and distribution of alien fish. K E Y W O R D Sboosted regression trees, Ebro River, environmental filtering, freshwater fish, habitat degradation, invasive alien species, joint species distribution model, native species decline, species co-occurrence

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Environmental filtering governs the spatial distribution of alien fishes in a large, human‐impacted Mediterranean river

Radinger

Alcaraz‐Hernández

García‐Berthou

2019

Diversity and Distributions

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“…The second most important environmental gradient within the Soyangho Reservoir was the change along the longitudinal dimension from the river inflow to the dam. River damming causes fundamental change in river hydrology and morphology (Schmutz and Moog 2018). The functions and services provided by the aquatic ecosystems are changed by these alterations in flow regimes Fig.…”

Section: Discussionmentioning

confidence: 99%

“…The elevations of the sampled communities and the Sorensen Similarity Indices calculated between the composition of the seedbank and their respective plant communities presented The different superscripts between values of the annual and perennial communities indicate the significant difference at α=0.05 by t test and morpho-dynamic patterns (Nilsson et al 2005). Damming rivers then creates new lentic ecosystems that resemble lake-type systems, but as they are continuously disturbed through managed water level fluctuations and flooding, the reservoir ecosystems become hybrid systems that lose some lotic functions, but partly retain some lacustrine ones (Schmutz and Moog 2018). A longitudinal gradient may develop from upstream reaches (riverine zone) throughout middle stretches (transition zone) to the dam (lacustrine zone) depending on the size and shape of the reservoir (Kimmel and Groeger 1984).…”

Section: Discussionmentioning

confidence: 99%

Vertical and longitudinal variations in plant communities of drawdown zone of a monsoonal riverine reservoir in South Korea

et al. 2019

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Background: The plant communities within reservoir drawdown zones are ecologically important as they provide a range of ecosystem services such as stabilizing the shoreline, improving water quality, enhancing biodiversity, and mitigating climate change. The aim of the study was therefore to identify the major environmental factors affecting these plant communities within the drawdown zone of the Soyangho Reservoir in South Korea, which experiences a monsoonal climate, and thereafter to (1) elucidate the plant species responses and (2) compare the soil seedbank composition along main environmental gradients. Results: Two main environmental gradients affecting the plant community structure were identified within the drawdown zone; these were a vertical and longitudinal gradient. On the vertical dimension, a hydrological gradient of flood/exposure, the annual-dominated plant community near the water edge changed to a perennial-dominated community at the highest elevation. On the longitudinal dimension from the dam to the upstream, plant species composition changed from an upland forest-edge community to a lowland riverine community, and this was correlated with slope degree, soil particle size, and soil moisture content. Simultaneously, the composition of the soil seedbank was separated along the vertical gradient of the drawdown zone, with mainly annuals near the water edge and some perennials at higher elevations. The species composition similarity between the seedbank and extant vegetation was greater in the annual communities at low elevation than in the perennial communities at higher elevation. Conclusions: The structures of plant community and soil seedbank in the drawdown zone of a monsoonal riverine reservoir were changed first along the vertical and secondly along the longitudinal gradients. The soil seedbank could play an important role on the vegetation regeneration after the disturbances of flood/exposure in the drawdown zone. These results indicate that it is important to understand the vertical and longitudinal environmental gradients affecting shoreline plant community structure and the role of soil seedbanks on the rapid vegetation regeneration for conserving and restoring the drawdown zone of a monsoonal reservoir.

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“…The environmental impacts of large dams are now well documented (Brandt, ; Grant, ; Petts & Gurnell, ; Schmutz & Moog, ; Williams & Wolman, ). These structures often retain large volumes of water, which lead to downstream hydrological changes, often affecting the entire range of flows.…”

Section: Introductionmentioning

confidence: 99%

Unclogging improvement based on interdate and interreach comparison of water release monitoring (Durance, France)

Loire

Piégay

Malavoi³

et al. 2019

River Research & Apps

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Large‐scale flow release experiments are becoming common for improving aquatic habitat quality downstream of dams. Because of the naturally high fine sediment load in the Durance River, France due to inputs from torrential tributaries draining badlands, unpredictable high flow events with dam overspill are not always sufficient to prevent clogging, which can lead to habitat degradation (especially spawning habitats) in bypassed reaches. Therefore, large‐scale flow experiments were conducted on four reaches to test the efficacy of clear‐water releases to improve aquatic habitat conditions. Continuous measurements of water depth, suspended sediment concentrations, and turbidity were conducted during twelve releases and compared on nine. Before and after each release, superficial clogging was measured. The study shows that there is a link between the volume of suspended sediments carried by water releases and the initial clogging. The volumes carried were low compared with the river's annual transport. The effect on clogging can vary significantly from one release to another. In particular, the hydrological context surrounding the releases has a significant influence on clogging. Comparisons of monitoring showed that releases are more effective on reaches that are more severely regulated (high hydrological control) than on those that are less well‐controlled. The areas with the highest initial clogging tend to unclog more than those with lower initial clogging; however, the latter zones are most impacted by ineffective releases. Performing a release on environments with low initial clogging can therefore be environmentally damaging. To ensure that releases are successful and that intervention is warranted, initial clogging should be measured in the field and releases should only be performed if the clogging is judged to be unfavourable.

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Dams: Ecological Impacts and Management

Cited by 100 publications

References 25 publications

Environmental filtering governs the spatial distribution of alien fishes in a large, human‐impacted Mediterranean river

Environmental filtering governs the spatial distribution of alien fishes in a large, human‐impacted Mediterranean river

Vertical and longitudinal variations in plant communities of drawdown zone of a monsoonal riverine reservoir in South Korea

Unclogging improvement based on interdate and interreach comparison of water release monitoring (Durance, France)

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