Spatial Reconstruction Of Cropland And Forest Of Jiangsu-Anhui Region In The Past 300 Years:Method And Case Study

Human-induced land use/land cover change(LUCC)has significantly affected the climatic and ecological processes at the regional even global scales,and it is an important driving force of global environmental change.Since the industrial revolution,the rapid development of science and technology,significant enhance of productivity,expanding population and obvious progress of social economy,has resulted in growing demand for food and resources,large quantity of cropland reclamation and deforestation,thus drastically changed the status of LUCC.The research on historical LUCC has been widely regarded as an important parameter for the research on pattern of land use,simulation of climate change and evaluation of ecological environment.As the study of global change continuingly intensifies,research on historical LUCC has been one of the hot topics of international concerns.Limited by the available data and the complexity of land use driving factors,the majority of existing historical cropland or forest study uses the reconstruction method based on "top-down" model of spatial distribution,but rarely takes the evolution process of land use or behavior characteristics of land use subjects into consideration.Therefore establishing the "bottom-up" method of*evolutional reconstruction of cropland and forest on historical time and producing a precise spatial data set,which is consistent with the changes of historical cropland and forest has its certain sense.Considering the behavior characteristics of land use subjects,this study developed a reconstruction model of historical cropland and forest based on Multi-Agent System.Taking moden land use pattern and potential natural vegetation distribution as the maximum potential scope of historical cropland and forest respecctively,building agents of macro(government)and micro(farmers)levels,this paper applied the reconstruction model to Jiangsu-Anhui Region,to rebuild spatial pattern of cropland and forest during 6 typical time sections with resolution of 1 km x 1 km.Draw the following conclusions:(1)The reconstructed cropland pattern was mainly distributed in the northern part of Jiangsu-Anhui Region in the starting year(1661).Southern Fu/Zhou(cities)in Anhui Province had barely no distribution of cropland while the Fu/Zhou(cities)in Hu-Ning Region had more cropland.From the perspective of pattern succession,area of cropland in Anhui Province mainly expanded along the Yangtze River Basin,but only Haizhou and Xuzhou had an obvious expansion in Hu-Ning Region.Within the reconstructing periods,the density of cropland in all Fu/Zhou had been continuously increased.(2)The spatial pattern of the reconstructed forest was mainly distributed in the Southern Anhui Province and the border area of Jiangsu Province and Anhui Province.The concentration of forest in Hu-Ning Region was not conspicuous,only sparsely distributed in northern Fu/Zhou such as Huai'an,Suqian and southern area like Nanjing-Zhenjiang-Yangzhou and Yixing.From the perspective of pattern succession,the spatial distribution of forest in Anhui Province especially along the Yangtze River and Hu-Ning Region both retreated rapidly.The concentration of forest declined continuously during the reconstructing periods.(3)The reconstruction results of cropland and forest of typical time sections in the past 300 years of Jiangsu-Anhui Region are proved to be rational according to the result verifications,which include the comparison with the existing results of cropland research,point-to-point verification and absolute error analysis with the modern forest pattern.