Increased flooding depth and duration limit post-submergence recovery of Bolboschoenus planiculmis

Flooding regimes critically regulate the growth, distribution, and composition of wetland plants, with depth and duration being key determinants. Bolboschoenus planiculmis , a perennial sedge species, serves as the primary tuber food source for Leucogeranus leucogeranus in the Momoge National Nature Reserve (MNNR) in northeastern China. This study aimed to investigate the effects of flooding depth and duration on this species, as well as its recovery performance following flood recession. A controlled pot experiment simulated 20-, 40-, and 60-day submergence periods under water depths of 0, 10, 30, and 50 cm, followed by 20 days of de-submergence. The results showed that increased flooding depths (30–50 cm) had detrimental effects on the performance of B. planiculmis . As flooding duration increased, the suppression of biomass accumulation became progressively more severe at deeper water depths (30 and 50 cm) compared to shallower ones (0 and 10 cm). All response variables after recovery were significantly affected by flooding depth, duration, and their interactions. Post-recovery biomass showed no significant differences between the 0 and 10 cm treatments across all durations. However, deeper flooding (30–50 cm) combined with prolonged submergence (40–60 days) severely impaired growth recovery. These findings highlight the vulnerability of B. planiculmis to prolonged deep flooding and underscore the importance of maintaining shallow water depths (≤10 cm) during the sprouting period to preserve its population. Such hydrological management is critical for sustaining Siberian crane foraging habitats. • Increased flooding depths (30–50 cm) had detrimental effects on the performance of Bolboschoenus planiculmis . • The effects of water depth on plant performance depend on flooding duration. • Post-recovery biomass showed no significant differences between the 0 and 10 cm treatments. • Deeper flooding combined with prolonged submergence severely impaired growth recovery. • The study highlight the importance of maintaining shallow water depths during spring to preserve its population.