Analysis of Zoige wetland landscape pattern evolution from 1991 to 2020
A wetland is one of the most ecologically functional ecosystems on the earth and plays an important role in water and soil conservation,climate regulation,and species diversity protection.This paper takes Zoige wetland as the research ob-ject,Landsat images from 1991 to 2020 as the research data,extracts wetland information based on the maximum likelihood method and then uses the calculated landscape pattern index and landscape component area transfer matrix to analyze the land-scape pattern evolution of Zoige wetland.The research shows that:1)Due to the particular terrain conditions in the study are-a,there are significant spatial differences in the distribution of wetlands in the study area.Large peat swamp wetlands are dis-tributed in the low-lying areas of Zoige County,the east of Maqu County,and the north of Hongyuan County.The wetland area in the east of the study area shows an upward trend,while the wetland area in the west,which is close to the east of Maqu County,is significantly lower.2)From 1991 to 2020,the wetland area change in the study area showed a trend of first decrea-sing,then increasing,then slowly decreasing,and the total wetland area decreased by 20 855.69 hectares.From 1991 to 2020,the fragmentation degree of the wetland landscape in the study area decreased and then increased,but the overall fragmentation degree of the landscape increased.In general,the change in wetland landscape fragmentation is small,and the overall landscape pattern of Zoige wetland has not changed much.3)The core landscape matrix in the study area is meadow,and the change trend of landscape components is that other components first convert into meadow in a specific area and then recover slightly,which is more prominent in the area change of herbaceous marsh.4)The increase in temperature and the decrease in precipita-tion,as well as the interference of human activities,accelerated the development of Zoige wetland from river → lake → peat swamp → herbaceous swamp → meadow → bare land.The degradation of Zoige wetland is not a simple natural process but a feedback result under the joint action of natural and human factors.
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