| Land use/cover change,as the most direct manifestation of the interaction between man and land system,has always been the focus and hotspot in the fields of sustainable development and global environmental change.The study of regional land use dynamic change can reveal the succession law of land use change under the disturbance of human activities,and it is an important way to study the regional environment change,which can be used to adjust and optimize the land use structure in the future,and provide scientific basis for the protection of ecological environment and regional sustainable development.Northeast area is located in the hinterland of Northeast Asia,which is an important agricultural and animal husbandry and commodity grain base in China.At the same time,it is also a sensitive region for global environmental change.The production and living activities of human beings have far-reaching effects on regional land use and cover change,even global environmental change.As a transitional area between agriculture and forestry,the agriculture and forestry in a farm-forest ecotone is interlaced in space and overlaps in time.It is precisely the most active ecological sensitive and fragile area with the most active natural factors and anthropogenic interference,which has an important impact on the regional ecological environment,such as soil properties,surface runoff and erosion,and so on.Taking Mudanjiang,a typical mountainous hilly region,as an example,RS and GIS techniques were used to interpret the land use in 1995,2000,2005 and 2015.With the help of the theory of Geo-information Tupu,this paper studied land use change and its spatial pattern evolution under the policy of returning farmland to forest.With altitude,slope,population,GDP,distance from roads and towns as driving factors,land-use suitability atlas was obtained by logistics analysis.And the land use pattern in 2025 was predicted by CA-Markov model in order to provide decision basis for regional land use planning and social and economic sustainable development.The results showed the following aspects.(1)The interpretation showed that the proportion of forest land in the study area was all over65%,the cultivated land accounted for more than 20%of the total area,and the proportion of grassland,construction land,water area and unutilized land was relatively small in four time nodes.The land-use transfer matrix showed that:the forest land showed an increasing trend from1995 to 2015,but it experienced the process of first decreasing and then increasing during the period;the dry land showed unstable changes from 1995 to 2015,and it experienced the process of first increasing and then decreasing and then increasing;the paddy field area continued to increase steadily,and the growth had slowed from 1995 to 2015.During the three periods of study,dry land were the biggest contributors to the increase of paddy land area.The grassland area continued to shrink,especially with low and middle coverage.The decrease in grassland from 1995-2000 was less than that from 2000-2005 and from 2005-2015,and most of it was transferred to dry land and forest land.The area of construction land increased from 2000 to 2015 and depended mainly on encroachment on paddy field,dry land and grassland.The area of water area showed the trend of first decreased,then increased and then decreased,and the reduction slowed down from 1995 to2015.The area of unutilized area was continuously reduced and the shrinkage amplitude was stable.The analysis of land use dynamic showed that the types of increase in area were construction land,paddy field,dry land and forest land,the types of reduce in area were grassland,water area and unutilized land.(2)The Tupu of land-use showed that the conversion of land-use types was intense from1995-2015,especially before and after the project of returning cultivated to forest from 1995-2005,and the land-use change was mainly between dry land,forest land,grassland and construction land.The repeated change atlas accounted for a large proportion of the area,and concentrated on the areas with larger slopes,such as hills and foothills.It is related to the increase of forest cutting height and the decline of forest margins before 2000.The area of grassland?grassland?forest land type was larger from 1995-2015,with a band of linear reduction,and it concentrated in the joint zone of forest land and cultivated land.It reflects the characteristics of land-use evolution under the policy of returning cultivated to forest,and the urbanization construction occupies a large amount of cultivated land.In order to balance the ecological environment protection,economic construction,grain production and other aspects of demand,the local government mainly through the transformation of low-medium-coverage grassland to forest land.(3)This paper selected five simulated scales such as 100×100 m,300×300 m,500×500 m,800×800 m,1000×1000 m,with altitude,slope,population,GDP,distance from roads and towns as driving factors.And then obtained the binary Logistic regression equations,and calculated the ROC value under the ROC curve.The best simulation scale is 500×500 m,and the ROC value is more than 0.75 of land-use types except the unutilized land,which can fit the relationship between the land-use spatial distribution and the factors.(4)The basic farmland was superposed as the limiting factor,and the land-use suitability atlas was generated on the basis of the binary Logistic regression equation.With the help of CA-Markov module in IDRISI 17.0,the land-use change of 2015 was simulated in the base period of 2005.Compared with the land-use map in 2015,the area prediction error of each land-use type is below5%except the unused land,and the overall Kappa coefficient is 0.94.The feasibility of applying the model in the study area is confirmed,and the changes of land-use types in 2025 can be predicted.(5)The results of land-use prediction in 2025 showed that the proportion of paddy field,dry land,forest land,grassland,water area,construction land and unutilized land is 3.31%,19.91%,72.12.%,1.32%,0.74%,2.46%and 0.03%respectively.Compared with 2015,the area of paddy field,dry land and construction land shows an increasing trend,with an increase of 29.86 km~2,35.02 km~2,349.84 km~2 respectively.The area of forest land,grassland,water area and unutilized land decreased by 294.46 km~2,86.65 km~2,18.73 km~2 and 15.47 km~2,respectively. |
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