Spatiotemporal dynamics of lake wetland in the Wanjiang Plain of the Yangtze River basin, China during the recent century

Numerous floodplain lakes in the world have been shrinking and gradually transformed into semi-closed res-ervoirs under the control of sluices for the past century, which has led to substantial ecosystem services loss. In this study, historical topographic maps 1930s and 1970s and remote sensing images (1980s-2020s) are used to reconstruct the centennial evolution characteristics of typical lakes in the Central Yangtze Ecoregion, i.e., the Wanjiang lake group. Moreover, we focus on their driving factors from the perspective of sluice control and agricultural activities. Results showed that the lake wetland area in the Wanjiang Plain shrank remarkably in the 1930s-2020s, with an overall loss rate of 45.32 %, of which 84.19 % was mainly in the 1930s-1970s. The wetland loss was accompanied by the dispersion of large lakes, the extinction and newbirth of small lakes. The uneven distribution of the wetland loss in space led to the overall migration of the lakes to the Yangtze River. These results can be explained as follows: from the 1950s to the 1970s, sluices were built on waterways between 91.67 % of lakes and the Yangtze River for flood mitigation. The flood risk control further led to the surge of building state-owned farms and personal polders in the local area from the 1950s to the 1980s, which was the primary cause for the loss of lake wetlands and the regularization of lake shorelines. Since the 1980s, lake protection measures have promoted the restoration of wetlands and reduced the rate of lake shrinkage to a certain extent. Our findings can provide important guidance for the sustainable management and possible hy-drological connectivity restoration project in the middle and lower reaches of the Yangtze River.