Effects of restorative treatments confirmed in a restored pond

Abstract

As a part of a plan to build the National Institute of Ecology, an eutrophicated farm pond was ecologically restored. As an artificial pond, the Yonghwasil Pond of a rectangular shape with a steep slope was improved to an elliptical shape of gentle slope. In order to improve the serious eutrophication problem, the sediments at the bottom were dredged. Furthermore, in order to induce the establishment of various plants, the maximum depth of the pond was increased to 2.5 m, and various depths were induced with a gentle slope. In the restoration of vegetation, riparian and emergent vegetation were first introduced to stabilize the space secured for the restoration of the pond, and the rest of the vegetation was left in the natural process. As a result, the Yonghwasil Pond, which was covered with simple vegetation due to severe eutrophication, was transformed into a complete pond landscape as various vegetation types established by reflecting the water depth and water table. The restoration effect of this ecologically restored pond was evaluated. In this pond, floating plants, emergent plants, wetland plants, and riparian plants are variously established by reflecting water depth and water table. As a result of stand ordination based on the vegetation data obtained from the restored Yonghwasil Pond and a natural lake selected as the reference site, the species composition resembled that of the reference site. Diversity based on vegetation type, community, and species levels tended to be higher than that of the reference site. The proportion of exotic species increased due to the disturbance that occurred during the restoration process, but continued to decrease as vegetation introduced for restoration established. Considering these results comprehensively, the restorative treatment served to increase both the biological integrity and ecological stability and, as such, achieved the restoration goal from the viewpoint of the pond structure. The Net Ecosystem Production (NEP) evaluated for vegetation settled in the 12th year after restoration showed a significantly higher level compared to forest vegetation. Therefore, the restored Yonghwasil Pond was evaluated to have a high restoration effect even in terms of function.