Early vegetation growth in an experimental restoration site in the Watarase wetland

  • Published source details Ishii J., Hashimoto L. & Washitani I. (2011) 渡良瀬遊水地の湿地再生試験地における初期の植生発達. Japanese Journal of Conservation Ecology, 16, 69-84.


This study is summarised as evidence for the following.

Action Category

Remove surface soil/sediment: freshwater marshes

Action Link
Marsh and Swamp Conservation
  1. Remove surface soil/sediment: freshwater marshes

    A replicated, site comparison study in 2007–2008 in an overgrown floodplain wetland in central Japan (Ishii et al. 2011) found that some plots stripped of topsoil and vegetation were colonized by new marsh vegetation, and that these plots contained more plant species over two growing seasons than adjacent unstripped land. Unless specified, results summarized for this study are not based on assessments of statistical significance. Vegetation colonized shallow-stripped plots (flooded 22–57 days/year) but not deeper stripped plots (flooded 215 days/year). Over the first two growing seasons, the stripped plots contained more plant species (102) than adjacent unstripped land (66). Sixty-five species only occurred in the stripped plots. The stripped plots also contained more plant species characteristic of wetlands/wet disturbed floodplains (stripped: 37; unstripped: 8), but a statistically similar number of alien plant species (stripped: 9; unstripped: 3). After two growing seasons, the shallow-stripped plots contained 0.7–11.1 plant species/m2 (including 0.3–2.2 wetland-characteristic), 7–167 plants/m2 (including 0.8–11.3 wetland-characteristic) and <5–33% vegetation cover. Invasive goldenrod Solidago altissima was absent from all stripped plots. Methods: In spring 2007, topsoil and vegetation were removed from ten 70-m2 plots on a goldenrod-invaded floodplain (two plots for each of five stripping depths; 1.5–2.7 m of topsoil removed). Vascular plants were surveyed between spring and autumn 2007 and 2008. All species were recorded in the stripped plots, plus cover and density in nine 1-m2 quadrats/plot/survey. Species were also recorded along transects in unstripped land within 50 m of stripped plots.

    (Summarised by: Nigel Taylor)

Output references
What Works 2021 cover

What Works in Conservation

What Works in Conservation provides expert assessments of the effectiveness of actions, based on summarised evidence, in synopses. Subjects covered so far include amphibians, birds, mammals, forests, peatland and control of freshwater invasive species. More are in progress.

More about What Works in Conservation

Download free PDF or purchase
The Conservation Evidence Journal

The Conservation Evidence Journal

An online, free to publish in, open-access journal publishing results from research and projects that test the effectiveness of conservation actions.

Read the latest volume: Volume 21

Go to the CE Journal

Discover more on our blog

Our blog contains the latest news and updates from the Conservation Evidence team, the Conservation Evidence Journal, and our global partners in evidence-based conservation.

Who uses Conservation Evidence?

Meet some of the evidence champions

Endangered Landscape ProgrammeRed List Champion - Arc Kent Wildlife Trust The Rufford Foundation Save the Frogs - Ghana Mauritian Wildlife Supporting Conservation Leaders
Sustainability Dashboard National Biodiversity Network Frog Life The international journey of Conservation - Oryx Cool Farm Alliance UNEP AWFA Bat Conservation InternationalPeople trust for endangered species Vincet Wildlife Trust