| Hulun Buir wetland is an important wetland ecological research area to maintain ecological security in Inner Mongolia..In order to explore the landscape type changes,landscape diversity and stability of this area.According to the research needs,related literature and interpretation features,this paper defines a set of wetland classification system based on MODIS images to describe landscape changes.Taking Hulun Buir wetland as the study area,acquisition of 21 remote sensing images from 2000 to 2020,and the wetland landscape cover type data are obtained by the method of threshold classification of decision tree.The characteristics of landscape dynamic changes are analyzed by means of transfer matrix,and the landscape diversity indexes are selected according to patch diversity,type diversity and pattern diversity,and then the characteristics of wetland landscape diversity are studied by the method of landscape pattern index analysis.The stability of each index on time scale is evaluated by the coefficient of variation CV in statistics.Furthermore,the entropy method is used to obtain the index weight of landscape pattern and based on the weight to build the landscape stability model,and then the landscape stability of Hulun Buir wetland is evaluated and analyzed.The results show that:(1)grassland and wetland are the main landscape types of Hulun Buir wetland.From 2000 to 2020,grassland landscape area,artificial landscape area and sandy land landscape area are decreased,forest landscape area and wetland landscape area are increased.The transformation among grassland,wetland and artificial landscape is the most frequent.(2)Landscape pattern changes: Analysis of the calculation results of pattern Index from 2000 to 2020 indicate that the degree of aggregation of various landscape types has little change at the type level in the past 21 years.Patch cohesion index(COHESION)in grassland and forest landscape is basically stable,the COHESION value of wetland and sandy landscape increases,while that of artificial landscape decreases,the results show that in the past 21 years,the connectivity of wetland and sandy landscape has increased,while that of artificial landscape has decreased,the landscape dominance of wetland landscape has increased in 21 years,and the landscape dominance of grassland landscape has changed significantly.the landscape dominance of artificial landscape decreased obviously.Only the fragmentation of wetland landscape is intensified.(3)Landscape diversity: From the analysis results,we can see that the change of landscape diversity on the landscape scale is more obvious.The overall sprawl index CONTAG of the study area changed greatly,dropped to the lowest value in 2008,increased sharply from 2008 to 2012,and then decreased rapidly,indicating that the landscape homogeneity in the study area decreased,connectivity became worse,SHDI and SHEI showed an upward trend as a whole,and the maximum value appeared in2008,when the landscape diversity was the largest,the degree of landscape heterogeneity was significantly enhanced,and the degree of landscape patch fragmentation increased.Generally speaking,in the past 21 years,the overall landscape patch shape tends to be complex,landscape dominance is low,and there is greater diversity.(4)Landscape stability: In terms of landscape stability on the time scale of landscape level and type level based on CV,except for LPI,the change range of other CV-based index landscape level is lower than that of type level.Overall landscape stability based on stability model,the difference of landscape stability of Hulun Buir wetland from 2000 to 2020 was 0.6806,and the change was obvious.The lowest value of stability was 0.1692 in 2004,and increased to the maximum value of 0.8498 in 2008. |
