The redistribution of water bodies in China: Gain, loss, and challenges

• Agricultural expansion and urbanization are the primary causes of water body loss. • Reservoirs and aquaculture ponds are key drivers of water body expansion in China. • Although stable in area, China’s water bodies are undergoing hidden losses. Under the dual pressures of human activities and climate change, lentic water bodies have experienced substantial changes, including losses and expansions. This paper provides an overview of the century-long trends in the number and area of water bodies in China and analyzes the loss and expansion of these water bodies. Over the past century, China’s water bodies have significantly declined in both numbers and areas. While the total area has remained stable in recent decades, smaller water bodies have disappeared rapidly. This significant loss has been primarily driven by human activities, particularly agricultural expansion and urbanization. Urbanization, in particular, has a more indirect impact than direct encroachment. At the same time, human actions have also led to water body expansion through the construction of reservoirs and aquaculture ponds. Climate change adds to these dynamics, as droughts transform water bodies into forests or grasslands, while in the Tibetan Plateau, increased precipitation and glacial melt expand lakes. These combined influences create significant spatial variations: in the east, lost water bodies become farmland, whereas in the west, they turn into grasslands. Over recent years, the balance between water body loss and expansion has stabilized China’s total water area. Nonetheless, the hidden loss of ecological functions and the decline of small water bodies remain concerns. Prioritizing the classification of small water bodies according to their characteristics and the development of effective management strategies is essential