Land Use/cover Change And Vulnerability Of Landscape Pattern In Sichuan Province

The expansion of the range of human activities and the intensification of their extent have caused changes in land use and land cover to varying degrees,and the resulting ecological environmental problems have been increasingly valued by people.At the same time,the pattern of land use and land cover is becoming more and more complex,and the influence of ecological processes and functions is constantly changing.The fragility of the landscape caused by this has become a problem that cannot be ignored at present.As an important strategic base for China's western development,Sichuan Province has received more attention in recent years along with its social progress and rapid economic development.This paper takes Sichuan Province as the research area and uses the MODIS data from the three phases of 2005,2010 and 2015 to analyze the land use/coverage changes of Sichuan Province in 2005-2010,2010-2015,and 2005-2015.The landscape pattern index analyzes the characteristics of vulnerability and spatio-temporal changes of landscape pattern,and discusses the ways of ecological restoration in fragile landscape patterns.The research results not only deeply understood the present situation of the resources and environment in the current research area,but also laid the foundation for the rational development and utilization of the research area land,and provided a reliable basis for the ecological protection and future planning and management of Sichuan Province.The findings and conclusions are as follows:(1)Taking Sichuan Province as the study area and MODIS remote sensing images of three phases in 2005,2010 and 2015 as the main data sources,the CART decision tree classification method was used to obtain the land use/coverage classification results of the third phase of the study area.Accuracy is above 80%.Between 2005 and 2015,the type of land use/coverage in Sichuan Province was dominated by forest lands and grasslands,and the sum of the total land use and land cover ratios was greater than 70%.In the study period,forest lands showed a tendency of increasing year by year.Construction land also showed a continuous increase trend.Grassland,unused land,and water areas showed a tendency of continuous decrease.Among them,the largest decline occurred in unutilized land,followed by grassland,and farmland was presented.First decline after the upward trend.(2)From 2005 to 2015,the land use/coverage types in Sichuan Province varied greatly.From the point of view of speed and degree,the area of three unused lands,grasslands,and water areas showed a rapid decline,and the dynamics of cultivated land in two periods of time.The positive value is negative after the first value,indicating that the total area of cultivated land is decreasing,the construction land and woodland dynamics are all positive,and the area is in a state of rapid increase.The intensity of the previous changes is greater than the construction land and water area.In the later period,it was indicated that the remaining land area change rate in the later period had a decreasing trend,and the land use intensity of the forest land was the strongest during the two research periods,indicating that the woodland area grew most significantly in the study area.The comprehensive index of the degree of land use in Sichuan Province shows a continuously rising trend,indicating that the overall level of land in the province is in a state of development.(3)Throughout the study period,there were mutual transformations between land use/coverage types in Sichuan Province.During the two periods of 2005-2010 and 2010-2015,the outflow of land in the land use/cover type transfer matrix was dominated by grassland,unused land,cultivated land,and forest land;land inflows were also forest land,grassland,cultivated land,and construction.The main land is used.(4)From 2005 to 2015,the landscape patches in Sichuan Province showed an increasing trend;the LPI values of forest land and construction land continued to increase;the LPI values of cultivated land,grassland,water areas,and unused land continued to decrease,and the changes in water areas were very small and maintained.At lower levels,the landscape diversity index of the study area is increasing,and the landscape dominance degree is decreasing.This reflects the decrease in the proportion of landscape types,and that the landscape types tend to be balanced in the landscape;land use in Sichuan Province The overall fragmentation degree of the coverage increased,and the overall fractal dimension of the landscape decreased slightly.This indicates that the distribution of land use/coverage types is decentralized and is continuously enhanced by human disturbance.(5)Using GS+ software to perform variogram fitting analysis of the sampling area,the results showed that the best variogram fitting models in 2005,2010 and 2015 were all exponential models,the fragility of the landscape pattern was clustered distribution,and the variance of the block gold accounted for the total.The ratio of variance shows a rising trend,but structural factors still dominate the spatial distribution of vulnerability of landscape patterns.The trend of shifts shows that the 10 km sampling scale chosen in this paper is the best spatial scale for the vulnerability analysis of landscape patterns,and has a strong spatial correlation.(6)Using spatial statistical analysis tools,the spatial interpolation of the vulnerability of Sichuan's landscape pattern was performed.The results show that the vulnerability evolution of the landscape pattern in the study area was opposite in 2005-2010 and2010-2015,and the vulnerability of the landscape pattern as a whole.Declined trend.The value of the Moran's I index of the landscape vulnerability of Sichuan Province showed a slight decrease in each period,indicating that the spatial pattern of the vulnerability of the landscape pattern in the study area was not random but intrinsically linked.The results of local spatial autocorrelation in Sichuan Province indicate that the fragility of the landscape structure has undergone significant changes in both the period 2005-2010 and 2010-2015.