| Land utilization and temporal&spatial variation are the reflection of interaction between humans and the nature,and also the important field of research on the global environmental change.Geology and geomorphology are the basis of all land developments.Lithology,structure and topographic features have influence and restriction on the land utilization.Research on features and rules of geology and geomorphology can provide important guidance for the improvement of land resource utilization.At present,the researches on the drainage basin's geomorphic development stage and geological&topographic feature relation are only limited for the qualitative description;,the quantitative research method for restriction effect of the drainage basin's geological&topographic conditions on the land utilization and change has not been reported.Jialing River Basin(Guangyuan Section)is the research area of this paper,with the quaternary geology and geomorphology principle as the guidance,which shall combine the theories and methods of watershed ecology,geostatistics and applied geology,adopt the remote sensing technology and geographic information system,and carry out the quantitative study of restrictions of basin geologic conditions on land utilization and change,on the basis of field investigation,basic geological data and previous research results.This paper adopts the area-elevation integral model to divide the drainage basin's geomorphic development phases,and analyzes the relationship of characteristic parameters,such as:the drainage basin's geomorphic development and geology,lithology,landform and drainage system;from multiple dimensions(time and space),this paper analyzes and studies the evolution process and rule of the land utilization pattern of the research area from 1990 to 2014,selects nine factors including the gradient,lithology and soil,and adopts the logistic regression analysis method to research the driving action of land utilization structure change.On the basis of system analysis,it could predict the probability of future land utilization change based on GIS spatial analysis technology,and provide the scientific evidence for rational utilization of land resources in the research area.Main conclusions are as follows:(1)The research area is Jialing River Basin(Guangyuan Section).This paper takes use of area-elevation integral model(HI value)to divide the research areas into the old age,maturity(toward old)and maturity phases;the area-elevation curve is in S shape,which meets the curve characters of drainage basin in the maturity phase.This phase is the balanced phase of geomorphic development.The area-elevation curve depends on the area and space.When the secondary reception basin threshold value is greater than24km~2,it is fit for carrying out the quantitative analysis on the drainage basin's geomorphic development of the research area.(2)By analyzing the relationship of parameters,including the drainage basin's geomorphic development stage,geologic age,lithology,drainage system and landform,it is found that the cretaceous system's stratigraphic distribution area gradually decreases from the maturity to old age phase,and there is no cretaceous system stratigraphic distribution in the old age phase.The old age phase(HI value is 0-0.35)is mainly distributed in Jurassic system,Quaternary system and Silurian system stratum,and less distributed in other geomorphic development phases;for the topographical parameters,compared to other two development phases(maturity(toward old)and maturity phase),the altitude and surface cutting depth value in the old age phase are lower,and the graded distribution is balanced.It is indicated that the basin erosion slows down at this period,and the terrain is basically stable and develops into the middle and lower mountain or hill with gentle slope.(3)According to the analysis on the drainage basin's geomorphic development and land utilization&change rules,the land utilization type of Jialing River Basin(Guangyuan Section)is mainly the forest land and arable land.From 1990 to 2014,the forest land and arable land are mainly transferred to the construction land.Transformation to water area,forest land and arable land from construction land is most obvious.Drainage basin's geomorphic development in different phases influences the area,rate,intensity and comprehensive dynamic state of land utilization change,and restricts the space pattern of land utilization change to some extent.However,the land utilization change direction is the same with the overall trend.On this basis,the paper selects the forest land and arable land change patches during 1990-2014,and analyzes the geological&topographic characteristic of the drainage basin's geomorphic development at different stages and the land change in spatial distribution;the results finds that the areas of land change ratio of the geomorphic development at different stages are different,and the influence of lithologic on the characteristics of the spatial distribution of land change is obvious,while the topographic parameters as the elevation,slope,and surface cutting depth determines the main land area of land change spatial distribution.(4)This paper makes use of land utilization in Jialing River Basin(Guangyuan section)at 1990,2000 and 2014,digital elevation model(DEM),and organic matter of surface soil to construct the space model of land utilization change based on logistic regression model.The result shows that the lithology,slope and elevation mainly influence the factors of land utilization change.Making use of ROC curve and point-by-point comparative approach to detect the precision of simulated results,it is found that this model has good forecast results on change of forest land and arable land.Under the remaining unchanged or similar conditions,the geological and geomorphological factor has strong influence on the land use type change.The model can effectively predict the space distribution probability of land utilization transfer in the future.(5)The result shows that the drainage geomorphic development can reflect the geological and geomorphological features in certain area and can restrict the space expansion pattern of land utilization.Forest land conversion probability of drainage geomorphic development in old age is high,which is caused by elevation,lithology and slope in the old age.Geographic and geomorphic conditions are also affected by the land use change.By this quantitative method,it could rapidly divide the geology and geomorphology characters in the research area,which can provide the reference and basis for efficient utilization of land resources and space pattern optimization. |
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