A Multi-Scale Simulation of Land Use Change in Luoyugou Watershed Based on CLUE-S Model
基于CLUE-S模型的罗玉沟流域多尺度土地利用变化模拟

The CLUE-S model is a special model, which has already been widely applied into the dynamic studies about the spatial pattern of smaller-scale regional land use change. To investigate the applicability and the best applicable scale of the CLUE-S model in small watershed, this paper has simulated the spatial pattern of land use change in 2008 in Luoyugou watershed of TianShui City, Gansu Province with this model at five different scales (25m×25m, 50m×50m, 75m×75m, 100m×100m,and 125m×125m) based on the land use data of 2001(as the base year) and 2008 and seven driving factors for land use change (digital elevation model, slope, slope direction, curvature, the distance to road, the distance to town center and the distance to river). Besides, the simulated maps were verified by the present land use map of 2008. The results show that the application of the CLUE-S model has got quite favorable results in the study area, and the best simulation scale is 50m. Under this scale, the Kappa indices of cultivated land, orchard, forest land, meadow, residential area, water area and unused land are 95.71%, 88.97%, 90.68%, 74.66%, 74.53%, 96.89%, 81.94% respectively and the aggregated Kappa index value of all study areas is 92.34%. Therefore, it has been proved that the CLUE-S model can accurately simulate the land use change in small watershed. The spatial patterns of land use under three different scenarios: the natural increase scenario, the economic growth scenario and the ecological conservation scenario in 2020 were also simulated by this model. At last, by comparing the simulation maps under three different scenarios, we get a result that the land use changes mainly happen on the hillside land with a slope larger than 15 degree. Therefore, during the process of development and utilization of Luoyugou watershed, a series of appropriate measures about the ecological protection and the prevention of water and soil erosion should be taken at the same time to prevent the ecological environment of the watersheds from serious destruction.