Study on Development Methods of Wetland Nutrient Criteria

The wetland ecosystem is highly productive and biologically diverse in nature and plays important roles in maintaining ecological health, regulating climate and protecting biodiversity, etc. However, affected by irrational development and human activity, the nutrient nitrogen and phosphorus in the wetland and the surroundings have excessively enriched, resulting in a series of problems such as degenerate species composition, decreased biodiversity, shrinking area and functional degradation. At present, many countries have paid close attention to the ecological conservation and management of the wetlands. Since the work in this field started late in China, it is urgently needed to advance the theories and technologies in ecological conservation and regulation. The wetland nutrient criteria are the highest acceptable concentrations or values, ecological effect of which does not impact the wetland aquatic ecosystem or downstream water use. The candidate variables used to establish nutrient criteria for the wetland include causal variables (e.g. nitrogen and phosphorus in soil and water column), biotic response variables (e.g. biomass) and supporting variables (e.g. hydrologic condition, conductivity and soil bulk density). Wetland nutrient criteria are the basis of eutrophication identification, assessment, management and ecosystem restoration for wetland, and they are thus significant for nutrient load control and water quality protection for the downstream water body.