What Drive Regional Changes in the Number and Surface Area of Lakes Across the Yangtze River Basin During 2000–2019: Human or Climatic Factors?
2022
Xu, Yuyue | Cheng, Xing | Gun, Zhao
The spatiotemporal distribution of lakes in the Yangtze River basin (YRB) has changed tremendously; however, research on how and why lakes changed across this basin is limited. In this study, based on Google Earth Engine, Landsat images were used to track lakes (>1 km²) across the YRB from 2000 to 2019. Then, the anthropogenic and climatic impacts on the evolution of lakes were fully discussed. Results showed that the distribution of lakes across the YRB was extremely uneven. From 2000 to 2019, the total number and the area (referring to the surface area) of lakes increased by 30 and declined by 885 km², respectively, but the trends of them were unobvious. In contrast, these changes and related causes exhibited high spatial heterogeneity. Lakes in the upper reaches significantly increased (P < 0.01). The expanded and new lakes were mainly distributed in the headwater catchment of the Yangtze River, which was closely related to increased precipitation. The number of lakes in the middle reaches decreased significantly (P < 0.05), which was primarily affected by intense human activities, such as land reclamation and agricultural irrigation. Precipitation played a dominant role in the fluctuation of the lake area here. In the lower reaches, the number of lakes increased (P < 0.01) as a result of the policy of “returning farmland to lakes,” while the expansion of area (P < 0.05) was closely related to the precipitation and runoff. These findings have important policy implications for the conservation of lake resources.
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