Scenario analysis of land use change and ecological sustainability based on GIS

Sustainability has become an important discussion topic across the world since the late 1980s. The sustainable development of the Chinese Loess Plateau has always been a focus in China mainly because of the occurring severe soil erosion. This study investigates the changes of the landscape pattern and the changes of the ecological sustainability of the agricultural landscapes in 5 fundamental land use scenarios that are proposed based on land use analysis, land suitability evaluation, planning and peasant´s demand in Ansai County, which is located in the northern part of the Chinese Loess Plateau. We combined expert judgement with a regression model and a geographic information system. Using a grid mesh of 600times600m size as a spatial reference framework based on the land use map, the concept of hemeroby was used for assessment ecological sustainability of agricultural landscape. Fourteen variables describing the landscape structure were chosen as predictors for ecological sustainability of landscape. The results suggested that the following land use scenario was recommended: all land with deep soil and slopes smaller than 15deg should be used for agriculture cropland, all farmland with slopes between 15deg-20deg should be converted to orchard or cash trees, and all farmland with slopes between 20deg-25deg should be converted to grassland. A great reduction of on-farm income, however, would be induced on the short term by such a scenario. On the long term, the scenario will be promising for ecological sustainability improvement.