Land Use Dynamic And Scenario Simulation By Integrating The System Dynamic And CA-markov Models In The Sandification Area Of Northern Shanxi

The northern Shanxi province located in the transitional zone of pastures and farmlands of the Loess Plateau of China.Serious land sandification has threated the social and economic sustainable development in this area.Simultaneously,the rapid growth of population and economy have caused the dramatic changes of the land use and land cover(LULC)spatial pattern,as well as the irrational LULC structure.This study took the sandification area of northern Shanxi as study area.Firstly,the LULC patterns in the years of 1986,1994,1999,2009,and 2014 were analyzed.Then I built up a simulation model for the LULC system in the study area using the system dynamic(SD)principle.Using this SD model,the LULC amounts in different scenarios were estimated.Moreover,I established an ecological security assessment system based on the DPSIR model,which was originally proposed by the Organization for Economic Co-operation and Development(OECD).The principal component analysis(PCA)method was then employed to assess the comprehensive ecological security statues.Lastly,the spatial patterns of the LULC under three different development scenarios were simulated by integrating the Logistic-regression and CA-Markov model.The results showed that:(1)In recent 30 years,the cultivated land widely distributed in the whole study area,and formed several strips along the northeast-southwest direction.Woodland mainly concentrated in the southeast of study area,and was relatively rare in western region.The grassland discretely distributed with cultivated land and woodland in whole study area.Residential land mainly distributed in Datong and Shuozhou urban areas,and sparsely appeared in the towns in the study area.Industrial and mining land was mainly distributed in west Nanjiao district of Datong and south Pinglu district of Shuozhou.Water area mainly located in east Nanjiao district of Datong.The distribution of saline land and bare land was rare and scattered.(2)The main LULC types of study area were cultivated land,woodland and grassland.Average,cultivated land accounted for 43%,woodland accounted for 21%,grassland accounted for 32%,and the other five land use types occupied about 4%.In 1986?2014,the acreage of cultivated land decreased after fluctuation,the woodland area first decreased and then increased,the grassland area first increased and then decreased,the acreage of residential land,industrial and mining land and bare land increased continuously.Water area decreased all the time,and saline land area increased after fluctuation.(3)The main type of land use transfer was mutual transformation of cultivated land,woodland and grassland.Average,the acreage of mutual transformation of cultivated land,woodland and grassland accounted for 90.82%of the total acreage of transformation.(4)The result of ecological security comprehensive assessment indicated that:in 1986?2014,the overall level of the ecological security status in the study area was at relatively low level,with a decreasing trend.In 1986 and 1994,the ecological security was at level ?,which indicated the study area was medium security status.In 1999,the security level declined to level II,which represented a low security status.The ecological security status kept in level ? from 1999 to 2014,however,the comprehensive indices had declined with time.It demonstrated that the ecological security continuously deteriorate in the study area.The ecological security status analysis in three different scenarios in 2020 indicated that,the score of scenario 1 was 0.45,the score of scenario 2 was 0.53,and the score of scenario 3 was 0.33.By analyzing the ecological security status in 2020,it could provide scientific reference for government to make policies to guarantee the ecological security of the area.(5)The result of scenario simulation of the LULC change in different scenarios in 2020 indicated that:scenario 1 represented the situation of current development trend of LULC.The LULC amounts changed accorded with the current trend in the study area without the restrict from external forces.Scenario 2 was the coordinated development situation of economy,society and environment,which was derived by coordinating development of above aspects.The acreage change accorded with the sustainable development of the study area.Scenario 3 stood for the situation of the LULC change if mainly focused on the economic development in study area.In the scenario,the pressure from economic and population development jeopardized the sustainable development of the LULC.The result of scenario simulation could provide reference for government to make decisions.