Objectives  The fishing moratorium policy in Poyang Lake has been in effect for a decade since 2020. Consequently, fishery in the “Plate-shaped Lake enclosed in Autumn” area within the Poyang Lake Nanji Wetland National Nature Reserve had also been suspended, experiencing significant shifts in the protection and utilization of natural resources. In 2022, Poyang Lake continued to grapple with the effects of extreme meteorological drought, resulting in the drying of plate-shaped lakes and backwater areas. Submerged plants, such as Vallisneria spp. were unable to grow and develop, leading to their demise within Poyang Lake. This phenomenon created a dire scarcity of food for wintering migratory birds, including submerged plants and snails. It will affect the foraging and distribution of rare species such as overwintering Siberian crane. To research and understand the temporal variation of Siberian cranes number and spatial distribution in Jiangxi Poyang Lake Nanji international important Wetland, and provide a scientific basis for the protection and management in the natural reserve.

  Methods  In this study, we focused our monitoring efforts on the Jiangxi Poyang Lake Nanji Wetland National Nature Reserve and its surrounding areas. Specifically, we analyzed the migration dynamics and spatial distribution of Siberian cranes (Grus leucogeranus) during the winter of 2022−2023 (October to April).

  Results  Our results revealed significant temporal fluctuations in the numbers of Siberian cranes. Notably, the duration of their habitation at the Poyang Lake Nanji Wetland National Nature Reserve during this wintering period exceeded that of previous years. On March 7, 2023, the highest count of Siberian cranes for the winter of 2022−2023 was recorded, totaling 524 individuals. These cranes arrived at the Poyang Lake Nanji Wetland National Nature Reserve in early November 2022 and began their northward migration in late April and early May 2023. From a spatial perspective, Siberian cranes predominantly inhabited the Poyang Lake Nanji Wetland National Nature Reserve, constituting 93.55% of the observed population. A smaller number of Siberian cranes were found in the paddy fields of Henghu and Zhugang around the Poyang Lake Nanji Wetland National Nature Reserve. Based on the timeline, the main habitation period for Siberian cranes was between mid-January and the last ten days of March 2023.

  Conclusions  It showed significant temporal fluctuations and spatiotemporal distribution in the numbers of Siberian cranes in Jiangxi Poyang Lake Nanji Wetlands of international importance. Influenced by food resources, they tended to spread to the surrounding areas. Finally, the author proposed several conservation strategies to enhance the management of vital habitats for overwintering migratory birds.