Research On The Mechanism Of Land Use Pattern Change And Its Simulation In Songnen High Plain

Land use pattern is the result of interaction between natural conditions and human activities.Land use pattern change process is nonlinear in time series,with characteristics of irregularity,relative instability and complexity.Land use pattern can affect the regional ecological environment,reflect the feature of regional land use and its advantages and disadvantages.It is an important basis for the regional land-use diagnosis.Human beings influence natural-resources structure and ecological environment,while developing and utilizing land and creating wealth.To analyze the spatial and temporal characteristics of land use pattern changes is an effective way to reveal changes in natural conditions and human activities.To explore the main influencing factors of land use pattern change,clarify its mechanism,simulate and predict its future trend have the important reference value in rational utilization of regional land resources,improvement of ecolo gical environment and revision of land use planning.The related researches on the mechanism and simulation of land use pattern change mainly focus on the overall change characteristics of land use types quantity and neglects its expression in space.And most of the researches are identifying the impact factors of different or single time periods,while the impact of the geographical location and spatial differences of the influencing factors on the land use pattern are used to be without consideration.This paper takes Bayan County in Heilongjiang Province as a researching area.Using RS and GIS technology to establish land use vector database at 4 time-points as 1979,1991,2003 and 2015.To clarify the relationship between land use types transfer modes,quantity and structure with the transfering matrix of land use types.According to land use dynamic degree,land use type conversion frequency,and land use structure information entropy,equilibrium degree and superiority degree and other index parameters are used to measure the frequency of land use type change,the degree of conversion between land use types and the order degree of land use structure.On this basis,to break the administrative boundaries,with square mesh product rule sample region to explore the spatial heterogeneity of land use change type spatial attribute,and to describe the spatial variability and distribution with distance.Among many natural and human factors that affect the land use pattern change,CCA(Canonical Correspondence Analysis)was used to screen and identify the key factors that affect the land use pattern change at different periods(1979-1991,1991-2003 and 2003-2015)in the reasearching area,and to analyze the size and direction of the key impact factors on the land use pattern.RBF(Radial Basis Function)was used to calculate the size and direction of the impact factors on different land use types,and to clarify the mechanism of the key impact factors on land use types.The spatial auto-correlation factor was introduced to construct the AutoLogistic regression model.To reveal the mechanism of key factors affecting on land use types spatial distribution in the reasearching area from 1979 to 2015.Using the improved CLUE-S model,combining the practice of the reasearching area and integrating the key factors of the land use pattern,the paper simulated the land use pattern under the natural development situation,the economic development,the cultivated land protection,the ecological protection and the comprehensive development scenario in 2027.The results of the study show that:(1)In the year of 1979-1991.1991-2003 and 2003-2015,the increasing and decreasing of land use types area are different.In the year of 1991-2003,the comprehensive dynamic degree of land use was the highest in study area.During this period,the changing of land use is frequent and the range is the greatest.In the three different periods,land use type conversion frequency index continuously increase was the paddy field,the first increase and then decrease were dry-land,garden land,forest land and other land,and the first decrease and then increase were grassland,construction land and water area.In the year of 1979-2015,the most frequently of land use type two-way change was dry-land,the roll-in is greater than the roll-out,the dry-land area is increased.The two-way change of other land was the most unfrequently one.The information entropy and equilibrium degree of land use structure first decreased and then increased,and the dominance degree increased first and then decreased in the researching area.The turning point was in 2003.In 2003,the land use structure remained in a low level of orderly state,the structure of land use needs to be improved,and the development and utilization of the land need to be strengthened in the researching area.(2)The land use types show gradient feature due to the impact of topographic factors in researching area.The dominance regions of different land use types are different.The degree of order,equilibrium and dominance of land use structure in the researching area have a certain gradient under the function of topographic factors.The information of entropy and the equilibrium degree of the land use structure show the same changing trend,the values of information entropy and equilibrium degree of the land use structure are larger in the areas with smaller heights and slopes.The trend of dominance is opposite to the information entropy and equilibrium,the dominance value of single land use type is higher in areas with larger heights and slopes.(3)In the year of 1979-2015,the most frequently converted land use types were dry-land and paddy,construction land,forest land,conversion between other land and dry land,paddy.The region of dry-land is being transformed into paddy mainly concentrated in Fujiang town,the region of dry-land is being transformed into construction land mainly concentrated in Bayan town and Xinlong Town,the region of paddy is being transformed into dry land mainly concentrated in Bayan Town and Xiji Town,the region of forest land and grassland is being transformed into dry-land mainly concentrated in Heishan Town,the region of grassland is being transformed into paddy mainly concentrated in Fengle Town,the region of other land is being transformed into dry-land mainly concentrated in Heishan Town and Dexiang Town,the region of other land is being transformed into paddy mainly concentrated in Xiguang Town and XijiTown.(4)The region with greater dynamics of land use is mainly concentrated in the northern part of the reasearching area,mainly distributed in paddy and grassland.The marginal areas in the southern part of the reasearching area are mainly distributed in water and other land.The junction region of Xiji Town Huashan Town and Songhuajiang Town,Bayan Town,Longquan Town were mainly distributed in paddy and water.The spatial trend of conversion frequency index of land use type shows significant in different periods.The land use structure is located in the high order level sample area mainly in the northern and southern marginal region of the reasearching area,such as the border region of Xiji Town,Huashan Town and Songhuajiang Town,Bayan Town,Longquan Town.The land use types are complex and diverse in this region.The dominant area of land use structure is mainly divided into dry land and forest land.(5)In the year of 1979-1991,1991-2003 and 2003-2015,the land use pattern change was affected by natural and human factors in the reasearching area.In these three different periods,the key factors that affect the land use pattern change were different,in terms of intensity,direction and way of the key factors on the land use pattern had changed.In the year of 1991-2003,the intensity and size of the key impact factors on the land use pattern were significantly higher than that of 1979-1991 and 2003-2015,which was the main reason for the frequency changing of land use types between the land use types and the large change in land use area.(6)In the year of 1979-1991,1991-2003 and 2003-2015,the main influencing factors that affect the land use types changing were different,and the effect intensity,direction and way of each influence factors on different land use types were different Under the common effect of influence factors,the area of land use type increases and decreases in different extent.Dry-land change has been greatly influenced by the land use intensity,and the intensity which indicated as decreasing significantly during the 1991-2003,and it was the main reason for the increasing of dry-land area in this period.The intensity of dry-land changes has been reduced by distance factors.The influence of water and soil moisture on the change of paddy was increased,which was the main reason for the increasing ofpaddy area in 2003-2015.(7)In the year of 1979-2015,the spatial distribution of different land use types was based on the common effects of natural and human factors,and there were obvious spatial differences in the constraints of the affected factors.The influence of landform factors on the spatial distribution of land use types was mainly reflected in the distribution of other land use types,except forest land which was restricted by terrain factors.The forest was mainly distributed in areas with larger heights and slopes,while other land use types were mainly distributed in areas with smaller heights and slopes.However,the influence of soil factors on the spatial distribution of land use types was quite different.The influence of distance factors on the spatial distribution of land use types was mainly reflected in the spatial distribution of dry-land and construction land was restricted by the distance from the town center,while the spatial distribution of paddy and water was restricted by the distance from rivers.The influence of land use degree on the spatial distribution of land use types was mainly reflected in the spatial distribution of dry-land and construction land was restricted by the intensity of land use,and it was mainly distributed in areas with large land use intensity.(8)Under the situation of natural development,the expansion of construction land invaded the surrounding dry-land and forest land,and the area of the paddy field increased more,and the main sources were dry-land,grassland and other land.Under the situation of economic development,construction land showed a significant outward expansion and occupied a lot of dry-land and forest land.The order of construction land patches increased slightly,and the stability index increased.The expansion of construction land was more concentrated than the state of disorder.Under the situation of ecological protection,the large forest land in the eastern part of the study area increased significantly,and concentrated with the original forest,the total value of land ecological services has improved significantly.Under the situation of cultivated land protection,the area where the paddy increase is basically expanded on the basis of the original paddy.The area of dry-land increased mainly in the whole researching area,the carrying capacity of the land population has increased significantly.Under the situation of comprehensive development,the area of dry-land decreased and the area of paddy increased.The total area of cultivated land is in the trend of growth,which plays an important role in ensuring food security.Dry-land area reduction is reflected in the whole research area.The increasing area of paddy is mainly based on the original paddy,and the areas increased are more concentrated with the original paddy.The area of forest land,grassland and water has increased,which play an important role in ensuring ecolo gical safety.The main reason for its expansion is occupied part of dry-land and other land.From the perspective of spatial distribution,the expansion of forest land is carried out on the basis of the distribution of the original forest land.The area of construction land,which plays an important role in economic development,has increased and expanded on the basis of the original built-up area.