Wetland Restoration
ページ内目次
Wetland Restoration
Degradation of the WetlandThis valuable wetland environment has faced serious problems for several decades. The wetland vegetation has been gradually changing. Originally, most of the vegetation in the Kushiro Wetland consisted of reed and sedge communities. However, alder forests have been encroaching on the wetland, and the proportion of reed and sedge meadows decreased from 92% in 1947 to 54% in 2004.
An increase in sediment inflow into the wetland has been recognized as a key factor influencing changes in wetland vegetation. Across Japan, land development was promoted after World War II to increase food production in response to population growth. In the Kushiro region, land near the wetland was converted into farmland through drainage and river channelization. These activities, combined with deforestation, resulted in increased sediment yield from areas surrounding the wetland. It was assumed that the increase in sediment inflow would lead to greater sediment deposition within the wetland, particularly in its marginal areas. This sedimentation altered habitat conditions, leading to a shift in vegetation from reed and sedge meadows to alder forests. Against this background, the Kushiro Wetland Restoration Project was initiated in 2003, with the primary aim of reducing sediment inflow into the central wetland area. 
Restoration works have been implemented at sites around the wetland. Sediment inflow has been reduced at points where rivers flow into the wetland, and the wetland environment has been restored by improving conditions in rivers and peatlands. 
Kushiro Wetland Restoration ProjectKushiro WetlandWetland Restoration Restoration Site 1 : Kayanuma, Old Channel Restoration 1 Restoration Site 2 : Numaoro, Old Channel Restoration 2 Restoration Site 3 : Kuchoro, Sediment Retention Basin Restoration Site 4 : Hororo, Reconversion of Farmland into Wetlands Kushiro Wetland Nature Restoration Council Project Goals Sediment reduction flowing into the wetland Implovement of habitat for fish Restoring Wetland Vegetation History 1 : Wetland Development History 2 : Shift Toward Wetland Conservation and Restoration Peatland |