| The impact of human activities and climate change on the landscape continues toincrease,leading to changes in the function and pattern of the landscape to varying degrees.The forest ecosystem,which is one of the most important terrestrial ecosystems,has suffered from serious disturbance.The change of forest landscape pattern and its driving force have been paid attention to,especially in the space and time of large scale and its driving force analysis.Sichuan Province has a pivotal role in the development of western China,and the impact of human activities and climate change on the landscape pattern of Sichuan Province has become increasingly prominent.In this paper,the forest distribution map of Sichuan Province(1981,1990,1998),the forest management zoning map of Sichuan Province(2008)and the MODIS(2008)were used as data sources.Based on ArcGIS,ENVI and FRAGSTAT,The distribution and dynamic changes of forest landscape patterns in four periods of 1981,1990,1998 and 2008 in Sichuan Province were analyzed by using the geography weighted regression model combined with other application data to change the landscape pattern of Sichuan Province from 1981 to 2008 And driving force to study,in order to provide a reliable basis for the management of forest management in Sichuan Province.The research prove that:(1)From 1981 to 2008,the area of the landscape type in Sichuan Province was the highest area of the two landscapes:the bare land and other land areas accounted for a larger proportion of the total area of Sichuan Province,and their total area accounted for the total area of Sichuan Province more than half.The area of bare land and other land area accounted for the largest proportion of the total area of Sichuan Province,above 30%,its area increased before 1998,after 1998 to reduce,but in general for the growth of forest land area in the research period is increasing.(2)Between 1981 and 2008,the area change of grassland in each landscape type was-44016.62 km~2,and the change of bare land and other area was 16858.03km~2.The overall change in forest land is 27158.59 km~2,which is manifested as a decrease before 1998,increased after 1998,and overall growth.During the study period,the maximum change of coniferous forest in the forest landscape type was 27198.11km~2,which decreased before 1998 and increased after 1998.The change of broadleaf forest,coniferous and broad-leaved mixed forest and shrub forest area,relatively small,respectively 6758.23km~2,-727.33km~2,-6070.42km~2.In general,the dynamic change degree of coniferous forest and grassland was 1.57%and-1.15%respectively,and the dynamic change degree of coniferous and broad-leaved mixed forest and shrub forest was-0.25%and-0.28%respectively.(3)The average patch area(AREA_MN)and maximum plaque index(LPI)showed a decreasing trend in the landscape pattern of Sichuan Province between 1981 and 2008,and the number of plaques(NP)and plaque density(LSI)and boundary(ED)showed a trend of continuous growth,while the average fractal dimension(FACT_MN)fluctuated,and the trend of landscape fragmentation was increased during the study period.(ENN_MN)showed a decreasing trend,and the distribution and parallelism index(IJI)showed a trend of increasing first and then increasing and then increasing,indicating that during the study period,the average distance(ENN_MN)and Shannon diversity index(SHDI)showed a trend of continuous growth,indicating that the landscape diversity and uniformity of Sichuan Province showed an increasing trend,and the trend of landscape diversity was increasing.Landscape heterogeneity increased,Sichuan Province,the diversity of the landscape has increased..(4)From 1981 to 2008,the change of plaque level in Sichuan Province showed that the number of patches(NP)and plaque density(PD)showed a trend of increasing gradually,and the degree of patching(PD)were lower than 0.05,and the landscape types were composed of large plaques.The growth of ED was slower during the period of 1981-1990,and the growth rate increased after 1990.This may be due to the acceleration of economic growth after 1990.(ED)is lower than that of other landscape types,indicating that the degree of fragmentation is lower than that of other landscape types.The average shape index(SHAPE MN)is lower than that of other landscape types.Showed a decreasing trend on the whole,and the grassland and shrub forest showed the trend of decreasing first and then increasing,and the other landscape types showed the trend of increasing first and then decreasing.The average fractal dimension(FRAC_MN)showed a tendency to increase first and then decrease,indicating that the complexity of plots of each landscape type is decreasing.(5)From 1981 to 2008,the geo-weighted regression analysis of the change of forest landscape pattern in Sichuan Province showed that terrain factors had a great influence on the change of forest landscape pattern in Sichuan Province,and the influence of socio-economic factors was the second,and the influence of climate factors was small.The terrain factors play a fundamental role in the change of landscape pattern.Although the socioeconomic factors have great influence on the landscape pattern,but the human activities have certain inertia and agglomeration.Climate change has little effect on the change of forest landscape in Sichuan Province.In the areas with low slope and low altitude,the effect on the change of forest landscape pattern is larger,and the degree of influence decreases gradually with the slope and elevation increasing,and the high value area tends to decrease first and then decrease.This is mainly due to the economic development and population growth between 1981 and 1998.The distribution of population density and GDP for the change of forest landscape pattern is also scattered,but the distribution of high value area is more and more concentrated to the eastern region.And the higher the population density and GDP,the greater the impact on the intensity of changes in the forest landscape pattern.After 1998,with the implementation of various large-scale forestry protection projects,the distribution of high-value areas is increasingly concentrated in areas with relatively high population densities in eastern Sichuan.The greater the value of temperature and precipitation,the greater the effect on the change of forest landscape pattern,and the more concentrated distribution of high value area to the eastern part of Sichuan Province.After 1998,with the strengthening of forest protection work,especially the implementation of natural forest protection project,the intensity of forest landscape pattern in the western region was reduced,which reduced the temperature of the western region to the high value area of forest landscape pattern,and concentrated to the eastern part of Sichuan Province. |
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