Deviation of hydrological regimes caused by blockage of hydrological connectivity: Implications for wetland restoration and management

Abstract

Deviation in hydrological regimes due to blockage of hydrological connectivity affects the wetland ecosystem and creates uncertainty in its interactions, especially in the ungauged wetland. This study investigates the differences in hydrological regimes that exist between isolated wetland patches, explores the impacts of these differences on the wetland ecosystem, and then discusses the implications of these findings for wetland restoration and management in the Jilin Momoge National Nature Reserve. Wetland InSAR was applied to identify hydrological blockage and assess the water level, and the ecosystem resilience was used to reflect the ecosystem states affected by the hydrological regimes. The following results were obtained: (i) although impeded by the low coherence of the radar signal, the water levels as assessed by the wetland InSAR reflected the deviation of the hydrological regimes in isolated wetland patches; (ii) the hydrological connectivity was altered by the rise and fall of the water level accompanied by the changes in hydrological barriers during the water abundance and deficit periods, resulting in the deviation of hydrological regimes; and (iii) the asymmetric trends can be deduced from the ecosystem resilience with an increase in the magnitude of water level fluctuation with a threshold of 0.07, 0.10 and 0.19 m in ErT, ELT and ND wetland patches respectively, indicating that even subtle deviations in hydrological regimes can lead to differences in wetland structure and function between wetland patches and induce uncertainties in wetland integrity. Taken together, these findings suggest that wetland restoration and management should focus on elucidating the hydrological mechanisms underlying wetland habitats using multiple scales (e.g. plot scale and regional scale) from a long-term perspective.