Integrating ecosystem-service tradeoffs into environmental flows decisions for Baiyangdian Lake

Abstract

Environmental flows play an important role in sustaining or enhancing the ecosystem services provided by wetlands. In this study, we quantified ecosystem services values and used the results to design an environmental flows regime for Baiyangdian Lake, the largest shallow freshwater lake in northern China. To do so, we proposed explicit tradeoffs among ecosystem services. We used emergy analysis to value the lake's ecosystem services from 1980 to 2011. We found that the regulating services contributed most to the total ecosystem services value from 1980 to 1989, followed by provisioning and cultural services; after 1990, the contribution of provisioning services became far greater than those of the other two services, followed by regulating services until 1998 and cultural services thereafter. We examined the relationships among the ecosystem services and environmental flow regimes, and found that regulating was strongly related and provisioning was moderately strongly related to all of the environmental flow components except for inflows; in contrast, cultural services were only weakly related to these components except for drought duration. Furthermore, we divided the study period's environmental flow regimes into four scenarios (high, intermediate, low, and extremely low flow regimes), which correspond to different environmental flow management strategies. Under the four scenarios, tradeoffs existed between all pairs of services. However, the intermediate flow regime provided the best overall tradeoff among the three services, and is therefore the recommended environmental flows regime. This form of analysis can therefore guide local environmental flows decisions that involve tradeoffs between different management objectives.