Ecological adaptation as an important factor in environmental flow assessments based on an integrated multi-objective method

Abstract

Abstract. An integrated multi-objective method for environmental flow assessments was developed that considered adaptation as a pivotal factor affecting how ecosystems respond to hydrological alterations. Responses of habitat area, and the magnitude of those responses as a result of fluctuations in river discharge, were established. The requirements of typical migrated species during pivotal life-stage seasons (e.g. reproduction and juvenile growth) were integrated into the flow-needs assessment. Critical environmental flows for a typical species were defined based on two primary objectives: (1) high level of habitat area and (2) low variability. After integrating the water requirements for various species with the maximum acceptable discharge boundary, appropriate temporal limits of environmental flows for ecosystems were recommended. The method was applied in the Yellow River Estuary in Eastern Shandong province, China. Our data show that, while recommended environmental flows established with ecological adaptation in mind may not necessarily benefit short-term survival of a typical resident organism on a limited temporal or spatial scale, they may encourage long-term, stable biodiversity and ecosystem health. Thus, short-term ecosystem losses are compensated by significant long-term gains.