Hydrological Conditions Mediate Habitat Use Plasticity of Wintering Geese in a Floodplain Wetland

ABSTRACT Floodplain wetlands such as Poyang Lake are increasingly shaped by hydrological extremes, yet the mechanisms linking hydrology to waterbirds' space use remain unclear. We aimed to quantify species‐specific distribution, habitat selection and behavioural plasticity across contrasting hydrological conditions to inform conservation and wetland management. We integrated satellite tracking of greater white‐fronted goose ( Anser albifrons ), bean goose ( A. fabalis ) and swan goose ( A. cygnoides ) with remote sensing and a hydrological classification derived from long‐term water levels and the SPEI. Individual winter home ranges and utilisation intensity were estimated, mapped, and linked to habitat types. Space‐use metrics were compared across hydrological categories (normal, drought, extreme drought) to assess species‐specific selection. Species differed markedly amongst hydrological years. Greater white‐fronted and bean geese had larger home ranges and higher mean utilisation intensity in drought and extreme drought years, whereas swan geese showed the opposite pattern. Hydrology strongly structured habitat selection: differences amongst habitat types were pronounced in normal and drought years but weakened under extreme drought. Fresh, sparse wet meadows dominated in normal and drought years; during extreme drought, use of mudflats and tall sedges increased, with parallel shifts in utilisation intensity. Wintering geese adjusted home range size, utilisation intensity, and habitat preferences under extreme drought, demonstrating pronounced behavioural plasticity and hydrology‐dependent space‐use strategies. By elucidating species‐specific mechanisms linking hydrology to habitat selection in a dynamic Ramsar wetland, this study advances habitat selection theory for floodplain systems and provides actionable guidance for conserving geese and managing Poyang Lake under increasing hydrological extremes.