Mapping spatiotemporal variations in lakeside populations for sustainable lake management.

Lakes provide a range of essential ecosystem services and disservices, with their impacts on human well-being closely tied to the spatial proximity between populations and lakes. However, the extent and dynamics of human exposure to lakes remain poorly understood at large scales. In this study, we present a comprehensive spatiotemporal analysis of lakeside populations (LP) across mainland China from 2000 to 2020, evaluating exposure patterns at national, regional, and provincial levels within multiple distance buffers from lakes. We further disentangle the relative contributions of population growth and lake area changes to LP dynamics using a control-variable approach. We found that (1) In 2020, 33.59 million, 18.04 million, 10.47 million, 7.24 million, and 3.59 million people lived within 2000 m, 1000 m, 500 m, 300 m, and 100 m of a lake, respectively, with the highest concentrations observed in the Eastern Plain and around small lakes. (2) Despite the regionally varied temporal dynamics, LP in China showed an overall increasing trend within 500 m, 1000 m, and 2000 m of lakes, but decreased during some periods within 100 m and 300 m buffers. (3) Between 2000 and 2020, LP changes in 70.37% of the examined provinces were dominantly impacted by lake area changes, particularly in northwest and southwest China. Yet, the main direct influencing factors changed dynamically during different periods. The increasing LP in China creates both opportunities and challenges for sustainable lake management. The spatiotemporal variability of LP dynamics highlights the necessity for scale-dependent and region-specific management strategies.