| In the new era,people are increasingly aware that unreasonable land use behavior will be subject to the merciless revenge of the natural environment.Rational use of land,correct understanding of the living environment,friendly protection of land resources,will be the infinite gift of the natural environment.The relationship between people and land in the areas with frequent mud-rock flow is tense,and the fragile and sensitive ecological environment threatens the safety of people's life and property.At the same time,people's unreasonable production development activities are bound to aggravate the environmental deterioration.Therefore,it is necessary to explore the mechanism and process of the interaction between human activities and debris flow activities in the areas with frequent debris flow,discuss the relationship between people and land,and realize the sustainable development of land and the coordinated development of ecology in the areas affected by debris flow.In this paper,the spatial relationship between the change of residents' land and the change of debris flow is taken as the starting point,the intensity and process of human activities are represented by the change of residents' land,and the process of debris flow activities is represented by the change of debris flow.Based on the information extraction of RS data,the spatial analysis and spatial statistics of GIS were used to analyze the residential changes and the influencing factors of debris flow activities in the debris flow disaster areas,and then the spatial relationship between human activities and debris flow activities in the Great and small white mud river basin was discussed.The following results were obtained:(1)the scale of residential land in the study area continues to increase,and its spatial distribution coexists with concentration and dispersion.The change of residential land is slow before fast in time,and the characteristics of each region are different in space.The change of residential land is the result of multiple factors.From the perspective of scale change,the total scale of residential land increased by 5.75 ha and the dynamic attitude was 0.73% from 1991 to 2004,and the total scale of residential land increased by 7.71 ha and the dynamic attitude was 0.89% from 2004 to 2017.From the perspective of spatial distribution,sparse area and dense area coexist,but the proportion of dense area gradually increases.From the analysis of spatial autocorrelation,the spatial distribution of residential land has a positive spatial correlation,that is,where there is more residential land,there will be more and more residential land,which is particularly obvious from 2004 to 2017.From the perspective of the evolution model of residential land,patches increase and patches decrease coexist,and new patches appear in areas rich in land resources.From the perspective of landscape pattern analysis,during the study period,the landscape fragmentation of residential land increased,the patches of residential land were different in the early stage,and gradually converged in the later stage,and the patch shape changed from complex and irregular to simple and regular.On the whole,in the second half of the study period,the intensity and speed of the change of residential land are greater than that of the first half.For the evolution of residential land,slope,water system,traffic and cultivated land are the main influencing factors,while elevation,precipitation and temperature have no obvious influence on the change of residential land.In short,the expansion of residential land generally occurs in the areas with good natural conditions,convenient transportation and abundant land resources,while the contraction usually occurs in the areas with deteriorating conditions or strong competition in the use of land resources.(2)the total scale of debris flow in the study area showed a trend of first increasing and then decreasing,and the change was slow and then fast.The overall spatial distribution did not change significantly,and the situation of debris flow disaster was gradually improving.From the perspective of scale,the debris flow increases first and then decreases,and the intensity and speed of change in the second half of the study period are stronger and faster than that in the first half.From the perspective of spatial distribution,the overall spatial orientation of the debris flow path has little change,but the center of mass in each stage has a certain amount of deviation.From the perspective of landscape pattern index,the landscape fragmentation of debris flow debris flow in the study area decreased,the difference between patches was small,the shape changed from simple rule to complex irregular,and the patch aggregation degree increased.The main factors affecting the debris flow activities in the study area are climatic hydrology geomorphic conditions and human activities.Among them,water system and geomorphologic conditions have the most obvious influence,followed by human activities,and precipitation has less influence.(3)there is a certain spatial correlation between residents' land change and debris flow track change.In the danger zone and transition zone of debris flow activity,the spatial correlation between the change of residents' land and the change of debris flow is strong.However,in the safe zone of debris flow activity,the correlation between the change of residents' land and the change of debris flow is weak.The increase of residential land will reduce the value of land ecological services in the region,that is,the ecological environment becomes fragile.The sensitive and fragile ecological environment is easy to breed debris flow,threatening people's life and property safety.We should make clear the interaction between human activities and debris flow,optimize the territorial space planning of the areas where debris flow occurs frequently,regulate debris flow in accordance with laws and local conditions,and realize the harmonious relationship between people and land and the sustainable development of land resources. |
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