Development Ecological Model of Vegetation for Isolated Former Floodplains in the Mangyeong River, Korea

초록

Most of rivers in South Korea were channelized by artificial levee constructions for flood protection and thus many floodplains were isolated by levees and were used as agricultural land and residential area. The river rehabilitations have been attempt to restore lateral connectivity in Korean rivers. This research describes the concept, methodologies and simulated results of the classification tree models (CART) that is used to simulate the effect of hydrological alteration by restoration of the lateral connectivity on vegetation dynamics in isolated former floodplains. The vegetation dynamics are simulated based on observed field data in the Korean rivers. Vegetation communities were classified into free-floating macrophyte, submerged macrophyte, emergent macrophyte, Phragmites spp., Salix app., annual & biennial plant and perennial Gramineae. The model simulates the changing vegetation patterns based on distributed physical parameters such as water level, velocity, flooding duration, topography and disturbance. The vegetation model was developed using digital elevation model (DEM) and raster data set of physical parameters based on global information system (GIS). The model was applied at the isolated former floodplain in the Mangyeong River, Korea. Topographical changes by restoration of lateral connectivity was simulated using GIS virtually, then hydrodynamic alteration was calculated by numerical model. The result of vegetation model showed that free-floating and submerged macrophytes were distributed mainly in water channel and Phragmites spp. was dominant and Salix spp. and perennial Gramineae were also existed in the floodplain. The floodplain vegetation model developed in this study is a step forward in modeling riparian vegetation dynamics and can be used for bioassessment and restoration projects of river and floodplain ecosystem.