Study

Restoration of Scirpus lacustris and Scirpus maritimus stands in a former tidal area

  • Published source details Clevering O.A. & van Gulik W.M.G. (1997) Restoration of Scirpus lacustris and Scirpus maritimus stands in a former tidal area. Aquatic Biology, 55, 229-246.

Actions

This study is summarised as evidence for the following.

Action Category

Add inorganic fertilizer before/after planting non-woody plants: freshwater wetlands

Action Link
Marsh and Swamp Conservation

Install physical supports for planted non-woody plants: freshwater wetlands

Action Link
Marsh and Swamp Conservation

Use fences or barriers to protect freshwater wetlands planted with non-woody plants

Action Link
Marsh and Swamp Conservation

Exclude wild vertebrates: freshwater marshes

Action Link
Marsh and Swamp Conservation

Directly plant non-woody plants: freshwater wetlands

Action Link
Marsh and Swamp Conservation
  1. Add inorganic fertilizer before/after planting non-woody plants: freshwater wetlands

    A replicated, paired, controlled study in 1987–1989 at the edges of three freshwater lakes in the Netherlands (Clevering & van Gulik 1997) found that adding fertilizer to plots planted with bulrushes Scirpus spp. had no significant effect on bulrush density (shoots/m2) or above-ground biomass (g/m2) over three growing seasons. This was true in six of six comparisons between fertilized and unfertilized plots (data not reported). Methods: In spring 1987, lakeshore bulrush Scirpus lacustris ssp. lacustris and saltmarsh bulrush Scirpus maritimus were each transplanted (12 plants/m2) into 24 plots (6–25 m2) at the margins of three freshwater lakes. In half of the plots at each site, fertilizer was buried alongside the roots of all plants (7.5 g/plant of Osmocote NPK). The other plots were not fertilized. All plots were fenced to exclude waterfowl. Bulrush shoots were counted, and shoot dry biomass estimated from length-mass relationships, in spring and summer until August 1989.

    (Summarised by: Nigel Taylor)

  2. Install physical supports for planted non-woody plants: freshwater wetlands

    A replicated, paired, controlled study in 1989 at the edge of a freshwater lake in the Netherlands (Clevering & van Gulik 1997) found that using wire mesh to support planted bulrushes Scirpus spp. had no significant effect on the number or biomass of bulrush shoots after two months. Bulrush plants in plots with and without support had a similar number of shoots in 12 of 12 comparisons (supported: 2–36 shoots/plant; unsupported: 2–26 shoots/plant) and had similar above-ground biomass in 12 of 12 comparisons (supported: 4–73 g/plant; unsupported: 2–51 g/plant). Methods: In May 1989, bulrushes were transplanted into 96 plots, each 4 m2, at the edge of a tidal freshwater lake. In 48 plots, plants were supported with strips of wire mesh (12 cm holes). There were four supported and four unsupported plots for each combination of two species (lakeshore bulrush Scirpus lacustris ssp. lacustris and saltmarsh bulrush Scirpus maritimus), two water levels (5 or 30 cm average depth) and three planting densities (2–20 plants/m2). All plots were fenced to exclude waterfowl. Bulrush shoots were counted and measured in July 1989. Above-ground dry biomass was estimated from length-mass relationships.

    (Summarised by: Nigel Taylor)

  3. Use fences or barriers to protect freshwater wetlands planted with non-woody plants

    A replicated, controlled study in 1987–1989 at the edge of a freshwater lake in the Netherlands (Clevering & van Gulik 1997) found that protecting plots planted with lakeshore bulrush Scirpus lacustris ssp. lacustris (using fences or wire netting) increased bulrush density and biomass after 1–2 years. In summer, fenced plots contained 300–360 bulrush shoots/m2 with above-ground biomass of 1,250–1,550 g/m2. Plots covered with wire netting contained 60–90 bulrush shoots/m2 with above-ground biomass of 110–280 g/m2. In unprotected plots, bulrush was not present. The pattern of results was similar, although density and biomass lower, in spring (see original paper). Methods: Twenty 6- or 16-m2 plots were established behind breakwaters at the edge of a lake. In May 1987, lakeshore bulrush was transplanted into all plots (12 plants/m2). Eight plots were then fenced to exclude wildfowl (12 cm wire mesh, 1.2 m tall). Six plots were covered in wire netting (2 cm holes) at ground level, to protect the roots from wildfowl. The final six plots were not protected. Lakeshore bulrush shoots were counted and measured in spring and summer 1988 and 1989. Above-ground dry biomass was estimated from length-mass relationships.

    (Summarised by: Nigel Taylor)

  4. Exclude wild vertebrates: freshwater marshes

    A replicated, controlled study in 1990–1991 in a freshwater marsh in the Netherlands (Clevering & van Gulik 1997) reported that fencing to exclude waterfowl maintained the density and biomass of lakeshore bulrush Scirpus lacustris ssp. lacustris over one growing season, but did not affect vegetation recovery over a second growing season. Statistical significance was not assessed. Over the first growing season, fenced plots contained more bulrush (density: 165–360 shoots/m2; above-ground biomass: 800–1,150 g/m2) than plots open to summer grazing (density: 70–225 shoots/m2; above-ground biomass: 200–510 g/m2). Over the second growing season, all plots were fenced and recovered to have similar bulrush density (315–450 g/m2) and above-ground biomass (1,210–1,480 g/m2) by late summer. Methods: The study used twelve 6-m2, tidal, lakeshore plots with 3-year-old bulrush stands. Four plots were fenced (12 cm wire mesh) in spring 1990 to protect them from further waterfowl grazing. The other eight plots were left open to one or two grazing events in summer 1990. All plots were fenced from autumn 1990. Bulrush shoots were counted and measured throughout the 1990 and 1991 growing seasons. Above-ground dry biomass was estimated from length-mass relationships.

    (Summarised by: Nigel Taylor)

  5. Directly plant non-woody plants: freshwater wetlands

    A replicated study in 1987–1989 of lakeshores planted with bulrushes Scirpus spp. in the Netherlands (Clevering & van Gulik 1997) reported that where bulrushes persisted over three growing seasons, their density, biomass and extent increased. Statistical significance was not assessed. After three growing seasons, lakeshore bulrush Scirpus lacustris ssp. lacustris was present in all three sites where it was planted. There were 370–390 shoots/m2 with 1,730–2,360 g/m2 biomass (vs only 70–130 shoots/m2 and 90–430 g/m2 biomass after one growing season). Saltmarsh bulrush Scirpus maritimus was present in two of three sites where it was planted. There were 70–220 shoots/m2 with 310–1,070 g/m2 biomass (vs only 20–40 shoots/m2 and 30–60 g/m2 biomass after one growing season). In the other site, plants were uprooted by muskrats Ondatra zibeticus. Finally, in four of four cases with data, bulrush had spread outside planted plots (by 27–372 cm, on average). Methods: In spring 1987, each bulrush species was transplanted (12 plants/m2) into 24 plots (6–25 m2) across three sites. All sites were at the margins of freshwater lakes and two were tidal. Half of the plots were fertilized at planting and all were fenced to exclude waterfowl. Bulrush shoots were counted, and above-ground dry biomass estimated from length-mass relationships, in spring and summer until August 1989. Lateral spread was recorded in July 1989.

    (Summarised by: Nigel Taylor)

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