Monitoring spatiotemporal changes of marshes in the Sanjiang Plain, China

•This paper analyzed the spatiotemporal changes of marshes from 1954 to 2015.•Marsh fragmentation was aggravated as a result of the large-scale reclamation in the Sanjiang Plain.•Our study first quantitatively separated the effect of human activities from natural factors in the study area.•Human activities play a dominant role (87.86%) in the spatiotemporal changes of the marshes in the study period.

The marshes have undergone dramatic loss in the Sanjiang Plain since the 1950s. This paper analyzed the spatiotemporal changes of the marshes using the transition probabilities index, loss rate, and landscape indices. We also used a trajectory analysis method to trace every location of marshes over multiple points in time and to quantitatively estimate the impact of human activities on the marsh changes since the 1950s. This study indicates that the marsh area declined sharply by 79.4% (approximately 2.99 million ha) from 1954 to 2015. A large area of marsh was reclaimed as cultivated land from 1954 to 2015. The changes in the related landscape indices showed the large-scale loss of the marsh area and marsh fragmentation in the study period. Human activities were the dominant factor (87.86%) that influenced the marsh changes in the Sanjiang Plain during the last 60 years compared with natural factors. These findings can provide valuable information for better understanding wetlands changes and implementing sustainable management strategies for wetlands (such as wetland restoration).