Change in macrophytic flora of Lake Takkobu, Kushiro, Japan, in past 30 years

Abstract

The change in macrophytic flora in Lake Takkobu since the mid-1970s was briefly described. At that period floating-leaved plant communities dominated by species such as Nuphar pumila and Potamogeton natans proliferated in the littoral zone of the lake, and many submerged plants occupied the whole area of the lake. From the 1990s some species began to decline because of the progressive eutrophication of the water. Except for Trapa japonica, which has become the most dominant species, many other species are in decline. To date some species seem to have gone extinct while others are threatened with extinction. In these 30 years, both the total biomass and species diversity of aquatic macrophytes have drastically decreased.