| In the development of human society,in order to meet the needs of mankind for resources and production and life,mankind must continue to develop and utilize resources in the natural environment,including water and land resources.In this process,the construction area of human beings has been continuously expanded,and the use of production and construction land has continued to increase,gradually occupying the area of arable land,and at the same time,the arable land has gradually extended to unused land,woodland and grassland.Gradually,humans have exerted a great influence on the landscape pattern in the region in various indirect or direct ways.While carrying out urban construction and economic and social development,it has also caused changes in the type and structure of regional landscapes,and the allocation of natural resources.Man-made interference has been carried out,which has interfered with the originally balanced ecological environment to some extent.For this reason,grasping the law of landscape pattern evolution,exploring the factors that drive the change of landscape types,and discussing the impact of natural environment changes and human activities in the cvolution of ladscape pattern have become enduring hot research issues.Yilong Lake is one of the nine plateau lakes in Yunnan Province.In recent years,due to lake pollution and climate drought,it has received many attentions due to its special geographical environment and landscape resource allocation.Analyzing and researching the landscape pattern changes in the Yilong Lake Basin can provide a scientific reference for future land resource utilization and landscape planning for management departments in the basin.At the same time,it can also promote the sustainable development of the natural resources of the river basin,and promote the harmonious and stable development of the river basin landscape pattern.In this paper,the Yilong Lake basin is used as the research area,and the five-year interval from 2000 to 2020 in the basin is interpreted by remote sensing imagery.The type of landscape studied is composed of cultivated land,forest land,grassland,construction land,water area and other land.Analyze the landscape types and change characteristics in the basin from 2000 to 2020 from the three aspects of landscape type composition change,landscape change rate and landscape type transition matrix;In this paper,combined with the analysis method of landscape pattern index,using Fragstats software,consider choosing a suitable landscape pattern index,and analyze the landscape pattern changes in the Yilong Lake basin from the patch type and landscape level.comprehensively consider the principle of selection of driving factors,the actual situation in the basin and the availability of data,and select 15 including natural factors,accessible The use of logistic regression analysis method and ROC curve verification analysis shows that the model and factors have a good degree of fit;natural and socio-economic factors are the driving factors which play a important role in the landscape pattern changes of the Yilong Lake Basin Analyzed.The main research conclusions of this paper are as follows:(1)From the perspective of landscape type structure,the landscape types of Yilong Lake Basin are mainly forest land and cultivated land,and the overall landscape structure has changed significantly.From 2000 to 2020,woodland has always been an absolute dominant landscape type in the watershed,and its area accounted for 48.37%in 2015;the area of the construction land landscape has been on the rise throughout the study period,with the area change rate as high as 256.65 in 20 years.%,the rapid expansion of the landscape area of construction land shows that human demand for land resources is increasing;the grassland area has decreased by 37.46 km~2,the area change rate is 47.01%,the area change is obvious,and the proportion of the landscape is also declining;(2)From the perspective of the transfer matrix,the area of construction land has increased from 14.29km~2 in 2000 to 50.98km~2 in 2020.Most of the increase in area is mainly from cultivated land.During the study period,28.84km~2 of cultivated land was converted into construction land.The main conversion sources of the area change of cultivated land landscape are woodland and grassland.The areas of these two types of landscape types converted to cultivated land during 2000-2020 are 24.73 km~2 and 20.43km~2 respectively;the area conversion of other land landscapes is also more obvious.During this period,8.27 km~2 of cultivated land was converted to other land,and 11.53km~2 of grassland was converted to other land.From the perspective of the transfer amount,the grassland landscape has a total area of 53.24 km~2.Except for other land,the main transfer direction is cultivated land and woodland..(3)From the perspective of the patch type landscape index,among all the landscape types,the waters have the highest degree of landscape aggregation;during the period2000-2020,due to the influence of human disturbance,the area of cultivated land continues to decrease,and the largest patch area index LPI totals The decline ratio is63.11%,the degree of landscape dominance continues to decrease,and the patch shape tends to become more complicated;the maximum patch area index of forest land has been at a higher level among the six landscape types,which is the dominant landscape type in the watershed.Its patch connectivity,combination degree and spatial aggregation degree are relatively high and relatively stable,and the patch complexity changes little;the patch area and patch type proportion of the construction land in the landscape PLAND has been constantly in the study period The largest patch area index is also increasing,and the landscape dominance is continuously increasing;the IJI value of the grassland landscape has shown a declining trend from 2000 to 2015,and the neighboring degree of other types of patches is continuously decreasing,and the probability of neighboring is also increasing.(4)From the perspective of the landscape index of the landscape level,during the period 2000-2020,the number of patches of all landscape patch types in the basin decreased by 499,and the landscape density increased by 14.33%;the growth of SHDI in 20 years was The increase of SHEI is 0.0186.The change trend of landscape diversity in the watershed is unstable,and the characteristics of landscape diversification and simplification appear alternately;the heterogeneity of the landscape continues to increase,and the degree of landscape fragmentation continues to increase.The degree of disturbance to the landscape structure continues to increase.(5)According to the results of the selected driving factors running in the Logistic binary regression model,the model's explanatory ability for each driving factor can meet the requirements of explaining the driving factors and landscape pattern changes,and the model has a high degree of fit.Among the 14 driving factors,the driving factors that are sensitive to changes in different landscape types are different;through the analysis of influencing factors,the landscape pattern of the Yilong Lake basin is greatly affected by the terrain slope and other aspects.Socio-economic is also one of the important factors leading to landscape pattern change. |
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