Spatiotemporal variations and tradeoff-synergy relations of ecosystem services under ecological water replenishment in Baiyangdian Lake, North China

Understanding dynamic variations of ecosystem services (ESs) and their tradeoff-synergy relations under ecological water replenishment (EWR) is conducive to the formulation of effective eco-environmental manage-ment strategies. In this study, spatiotemporal variations of three leading ESs, namely habitat quality, carbon storage and water yield services influenced by EWR in Baiyangdian Lake, North China from 1991 to 2019, were investigated using the "Integrated Valuation of Ecosystem Services and Tradeoffs" (InVEST) model, and their tradeoff-synergy relations were quantitatively assessed with correlation analysis methods. Our results showed that habitat quality had continuously declined, whereas it got a steady improvement after the year of 2015. Total carbon storage was relatively stable, and the volume of total water yield and precipitation showed the same variation trend. Overall, EWR promoted the maintenance and improvement of ESs. Tradeoff-synergy relations among ESs varied with time and space. Temporally, there was an obvious synergistic relation between habitat quality and carbon storage services. Spatially, these two ESs were synergistic in the southern, central and eastern parts of the lake, while they had a tradeoff relation in the north; and there were no tradeoff-synergy relations between the water yield service and these two services. This study confirmed the importance of zoning man-agement and comprehensive multi-factor management based on spatial and temporal differences of ESs, and can offer a scientific basis for adaptive eco-environmental management strategies for wetland restoration.