Ecological Studies on Management of Grassland Vegetation on the Embankment Slope I. Effect of Cutting on the Embankment Vegetation at the Niyodo River

Abstract

We would like to report on the results of our investigation into the effects of cutting on the grassland community. Field experiments were conducted on the embankment grassland community at the Niyodo river in Kochi Pref. from 1986 to 1991. In order to clarify the effects of cutting frequency on growth, number of species, life-forms, floristic composition and species diversity of the community in which Miscanthus sinensis and Imperata cylindrica var. koenigii were dominant, four experimental plots cut at different frequencies (twice per year, once per year, once per two years and no cutting) were designated in the community. In the plots with no cutting, one cutting per two years and one cutting per year, the communities were progressively dominated by Miscanthus sinensis. Only in the plot that received two cuttings per year did the community remain dominated by Miscanthus sinensis and Imperata cylindrica var. koenigii. In the plots that received no cutting and one cutting per year, the number of species and species diversity of the community were reduced. By contrast, in the plots that received one and two cuttings per year, the number of species and species diversity of the community remained at the same level as when the experiments started. Seasonal change was clearly evident in the plots that received one and two cuttings per year, whereas it was not evident in the other plots. This resulted in the reduction of summer annual plants because of the extreme domination of Miscanthus sinensis.