Aquatic plant management: ecological effects in two streams of the Swiss Plateau

Kaenel, Barbara R.; Uehlinger, Urs

doi:10.1007/978-94-017-0922-4_36

Cited by 9 publications

(10 citation statements)

References 2 publications

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“…The decreases of the values of community parameters after the macrophyte removal were most pronounced in the top two layers and decreased along the vertical profile of the barrier bed. A decrease in macroinvertebrate numbers was also recorded in previous studies of macrophyte removal (Dawson et al, 1991;Kaenel & Uehlinger, 1999) but mostly for the taxa that used the macrophytes as habitat (macroinvertebrates were removed together with the macrophytes). In this study, the decrease in macroinvertebrate density should be associated mostly with the flow velocity decrease since the research was conducted in areas between the macrophyte stands.…”

Section: Discussionmentioning

confidence: 92%

The impact of aquatic macrophyte (Salix sp. and Cladium mariscus (L.) Pohl.) removal on habitat conditions and macroinvertebrates of tufa barriers (Plitvice Lakes, Croatia)

et al. 2006

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The effects of aquatic macrophyte (willows and sawgrass) removal on flow velocity, tufa deposition, POM dynamics, and macroinvertebrate community structure were studied in the tufa barrier habitats of the barrage system of Plitvice Lakes, Croatia. Samples were collected from two hydraulic habitats (fast > 100 cm s )1 and slow < 100 cm s )1 ) at both a control (no macrophytes removed) and impact (macrophytes removed) site. Samples were collected with a core sampler (four layers in vertical profile of barrier bed) monthly on 6 dates before and 7 dates after the removal of macrophytes. Macrophytes were removed in May 2002 at the impact site. After the macrophyte removal flow velocity decreased significantly at both hydraulic habitats. Retarded flow resulted in: (a) a decrease in macroinvertebrate density and diversity since most of the taxa were rheophilic (preferring habitats with higher flow velocity) and (b) an increase in POM concentrations (FPOM and UPOM) since decreases in flow velocity facilitate particle deposition in lotic habitats. The effects of macrophyte removal were present, and diminish along the vertical sediment profile of the barrier bed. Tufa deposition was not influenced by the macrophyte removal.

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Section: Discussionmentioning

confidence: 92%

The impact of aquatic macrophyte (Salix sp. and Cladium mariscus (L.) Pohl.) removal on habitat conditions and macroinvertebrates of tufa barriers (Plitvice Lakes, Croatia)

et al. 2006

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“…Wright, 1992, Dawson et al, 1991, Kaenel and Uehlinger 1999 with highest loses for those animals most strongly attached to the macrophytes (e.g. Pearson and Jones, 1978) or at key stages in their life cycle (e.g.…”

Section: Invertebrate Populationsmentioning

confidence: 99%

Instream and riparian implications of weed cutting in a chalk river

Old

Naden

Rameshwaran

et al. 2014

Ecological Engineering

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were monitored at a site on the River Lambourn (The CEH River Lambourn Observatory) and major instream and riparian impacts were observed. Measurements clearly demonstrated how weed cutting enhanced flood flow conveyance, reduced water levels (river and wetland), increased river velocities, and mobilised suspended sediment (with associated chemicals) and reduced the capacity for its retention within the river channel. Potential implications in relation to flood risk, water resources, downstream water quality, instream and riparian ecology, amenity value of the river, and wetland greenhouse gas emissions were considered. Provided the major influence of macrophytes on instream and riparian environments is fully understood then the manipulation of macrophytes represents an effective management tool that demonstrates the great potential of working with nature.

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“…Old et al., ). This is surprising considering that maintenance has a tremendous effect on the ecology of the streams (Armitage, Blackburn, Winder, & Right, ; Baattrup‐Pedersen, Göthe, Riis, & O'Hare, ; Baattrup‐Pedersen et al., ; Dawson, Clinton, & Ladle, ; Kaenel & Uehlinger, ). Instead, maintenance is performed under the assumption that removal of aquatic plant biomass improves flood protection and run‐off from agricultural land if applied regularly (Bach et al., ; Old et al., ; Vogelsang, ).…”

Section: Introductionmentioning

confidence: 99%

Evaluating effects of weed cutting on water level and ecological status in Danish lowland streams

et al. 2018

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At present, scientific evidence documenting effects of weed cutting in streams as a measure to improve flood protection and run‐off from agricultural land is scarce, which is surprising considering the huge effect that it has on stream ecology. Instead, weed cutting is performed under the assumption that removal of aquatic plant biomass improves runoff from agricultural land and prevents flooding of adjacent areas provided that it is performed regularly. In this study, we examined linkages between weed cutting practice and water level reductions in 126 small‐ and medium‐sized Danish streams (catchment size <100 km2) with continuously monitored discharge and water level data (from 1990 to 2012). Specifically, we hypothesised that (1) weed cutting reduces stream water levels more in late summer when the biomass of aquatic plants is higher than in early summer; (2) the efficiency of cutting declines with increasing cutting frequency as the aquatic plant community changes with increasing abundance of species able to regrow fast following a cutting event; (3) the high‐frequency cutting in Danish streams lowers the ecological status of the streams as evaluated from aquatic plant assemblages. The average effect of weed cutting on the water level was largest in July, August and September with an average reduction of 16 cm and lowest in early spring and late autumn with an average reduction of 11 cm. Regrowth was largest in June, with an increase in water level of 0.41 cm/day, whereas regrowth was absent in autumn. Regrowth also varied with the frequency of weed cutting, from an average of 0.04 cm/day in streams subjected to one annual cutting to an average of 0.6 cm/day in streams subjected to >6 annual cuttings. Furthermore, we found that the ecological status was either moderate or poor/bad in streams with more than one annual cutting. Our findings highlight that it is by no means certain that the current weed cutting practice is efficient for flood control since (1) regrowth is stimulated by frequent cuttings and a positive feedback loop may develop, necessitating even more frequent cuttings to maintain the discharge capacity of the streams, and (2) many species stimulated by weed cutting, like for instance Sparganium emersum, form dense canopy beds across the entire stream profile and therefore reduce the discharge capacity of the stream more than species growing in confined patches. We encourage more studies with the aim to identify how stream maintenance should be performed to optimise flood control without compromising the ability to reach good ecological stream quality.

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Aquatic plant management: ecological effects in two streams of the Swiss Plateau

Cited by 9 publications

References 2 publications

The impact of aquatic macrophyte (Salix sp. and Cladium mariscus (L.) Pohl.) removal on habitat conditions and macroinvertebrates of tufa barriers (Plitvice Lakes, Croatia)

The impact of aquatic macrophyte (Salix sp. and Cladium mariscus (L.) Pohl.) removal on habitat conditions and macroinvertebrates of tufa barriers (Plitvice Lakes, Croatia)

Instream and riparian implications of weed cutting in a chalk river

Evaluating effects of weed cutting on water level and ecological status in Danish lowland streams

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