| Yilong Lake,located in Shiping,Yunnan Province,is one of the nine plateau lakes in Yunnan Province.It has higher social and economic value of survival and development environment.In recent years,not only because of its special geographical location,but also because of climate drought,lake shrinkage,ecological degradation and other problems have attracted much attention.On the one hand,the systematic and comprehensive calculation of the morphological characteristics of Yilong Lake can reasonably utilize,protect and plan the resources of the lake area,and then better identify the change law of the morphological characteristics of Yilong Lake,reflect the succession law of lakeshore habitat,and provide preliminary ideas for the study of lake ecology.On the other hand,in response to ecological civilization construction,further research on the trend of complex ecological change of lake basin based on remote sensing technology can provide scientific management direction for the ecological protection of lake,and provide certain theoretical support for the study of lake ecology,which has positive practical significance.In this paper,based on remote sensing data and Canny operator,the shoreline of Yilong Lake is automatically extracted,and the metric index of lake morphology is calculated.Combined with the fractal theory,the morphological characteristics of Yilong Lake and its driving factors are analyzed in the past 20 years.Based on the measurement index,the ecological significance of the factors related to shoreline complexity and their characteristic changes is studied to reveal the potential relationship between shoreline complexity and its related factors and the ecological environment changes of the lakeside zone.At the same time,remote sensing ecological assessment model is used to dynamically monitor the lake and basin,and analyze the succession characteristics of the lake and basin ecological environment.Based on the remote sensing ecological assessment model combined with the ecological significance represented by the complexity of the shoreline,the stage model of ecological evolution of Yilong Lake was finally divided,and provide the ecological governance of reference suggestions.The paper has achieved the following results:(1)In the past 20 years,the morphological characteristics of Yilong Lake have changed significantly,and the herringbone degree of the shoreline has undergone a complex-simple-complex-simple process.The lake perimeter and area also show obvious fluctuating changes,especially in 2013,the perimeter and area values are more prominent,18.5203 km and 11.6929 km~2 respectively.Previously,the perimeter length was 39.5022 km and area was 28.2995 km~2 in 2010,which meant that the lake form had shrunk to less than half of its original size,and in 2017,the perimeter length expanded to 36.8607 km and area rebounded to 19.7677 km~2,which is an uncommon phenomenon for inland lakes in the highlands,because the lakes change water more slowly and generally do not have such a big change.(2)According to the evolution law of the morphological characteristics of Yilong Lake,the driving factors of natural conditions and human activities are mainly discussed.According to the meteorological data,there was a serious shortage of precipitation in the lake area from 2008 to 2014,and the shortage of precipitation was one of the reasons leading to the change of the lake area.At the same time,under the background of regional warming,it is found that the change of temperature may have a certain influence on the complexity of shoreline.In addition,human activities are bound to interfere with the lake,so human beings should plan the lake resources as reasonably as possible when developing and utilizing the lake.(3)This paper describes the complexity of shoreline through quantitative methods,studies the ecological significance of the complexity of shoreline and its related factors,and reveals the potential correlation among the complexity of shoreline,the shape of lake,and the ecological environment of lakeside zone,namely:The more complex the lake shape,the higher the shoreline complexity,the greater the SDI value,the better the ecological environment,the more diverse the lakeside community,the higher the primary productivity;on the contrary,the simple lake shape,the lower the complexity,the lower the shoreline development coefficient,the worse the ecological environment,the lower the lakeside biodiversity,the lower the primary productivity.(4)Based on the management concept of"lake-basin"ecological environment,the ecological evolution characteristics of the lake basins were discussed based on the remote sensing ecological assessment model and the evolution law was obtained.Then combined with the ecological significance of shoreline complexity,the ecological evolution model of Yilong Lake can be specifically divided,namely:(1)From 2000 to 2010,in the initial ecological period,the ecological environment changes were mainly affected by natural conditions;(2)From 2010 to 2013,in the ecological damage period,the ecological environment changes were affected by natural conditions and human activities;(3)From 2013 to 2019,in the period of ecological governance,human intervention is to further accelerate the comprehensive treatment of Yilong Lake.Although human activities during this period mainly affected the natural development of ecological environment changes,both natural conditions and human activities during this period had certain positive effects on the balanced and stable development of ecology,which also hinted at the gradual harmonious coexistence between human and nature. |
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