Long-term dense Landsat observations reveal detailed waterbody dynamics and temporal changes of the size-abundance relationship

Surface water bodies in Hunan Province, China. Surface water bodies (WB) are important for agriculture, aquiculture, and aquatic and terrestrial ecosystems, yet monitoring and understanding the spatiotemporal dynamics of water bodies over large areas remain a major challenge. This study used all the available Landsat images and the Google Earth Engine (GEE) to map and analyze annual changes of all water bodies (>0.001 km2) in Hunan Province, China, from 1987 to 2020. A total of 76,928 WBs were detected with a total area of 4181.14 km2 (both were averages during the study period) with an interannual variability of − 117 and − 20.05 km2 year-1, respectively. Surface areas of small (0.001–1 km2), medium (1–50 km2), and large (>50 km2) WBs changed at various rates and directions. The size-abundance relationship of WBs followed the power scaling law with a positive trend in the scaling exponent, implying the fraction of small WB number has decreased over the past three decades. The temporal change of the size-abundance relationship, reflects the strong and dynamic imprints of both human activities and regional climate change. Future research should strive to understand the temporal change of the size-abundance relationship of WBs as it is important for water resources management and estimating the temporal changes of greenhouse gas fluxes from WBs over large areas. •Landsat time series revealed unprecedented details of waterbody dynamics.•Areas of small, medium, and large waterbodies changed at various rates and directions.•Size-abundance relationship of water bodies exhibited temporal change.•High geographic variability of change was driven by land use and climate change.