Simulation of the spatial stress due to urban expansion on the wetlands in Beijing, China using a GIS-based assessment model

Abstract

Based on the existing Urban Expansion Dynamic (UED) model, this paper develops a geographic information system (GIS)-based model that can be used to assess the current and potential spatial stress on a regional wetland ecosystem due to urban expansion. Synthetically utilizing the simulation capability of the UED model and the spatial analysis power of a GIS, this new model takes into account the present disturbance by ongoing urban expansion, the potential disturbance by future urban expansion, the accessibility via the transportation network, and the neighborhood stability. The model is used in particular to simulate the spatial stress on the major wetlands in Beijing from 1991 to 2004. The simulation results are found to be consistent with the actual remote sensing observations: a relatively high spatial stress normally leads to an eventual conversion into urban use. With the future urban lands predicted by the UED model, this model is used to further assess the potential spatial stress of urban expansion on the major wetlands in Beijing by 2015. Moreover, the spatially stressed wetland fringe areas in Beijing are identified based on the total spatial stress combining the current and the potential. These areas are found to be mainly distributed in downtown Beijing and the plains areas that have relatively easy accessibility via the transportation network. Effective measures should be taken to protect such areas from being further disturbed in order to achieve the goal of a more effective conservation of the wetland ecosystems in Beijing.