Ecosystem Health Assessment In Cuihu Wetland

Wetland is one of the three great ecosystems on the earth, which is crucial to maintain the regional ecological balance and is an important guarantee of human society. Therefore, wetland health assessment has become the main direction of wetland research. The wetland assessment method proposing by the United States Environmental Protection Agency was modified to study the wetland ecosystem health of Cuihu wetland, and the health assessment was under three assessment level. The research results are as follows:(1) The landscape development intensity index of Cuihu wetland was 1.55, and the landscape score was 10, which are within the scores of nearly natural type. Therefore, Cuihu wetland has a complicated boundary shape, and is little disturbed by human beings.(2) In order to cover the shortage of the rapid assessment method, two quantitative indicators including birds and fish factors were selected to supplement the qualitative assessment. The total score of Cuihu wetland was 0.79, indicating that the wetland ecosystem is in good health condition. The evaluation result of Level Ⅱ is same as the Level Ⅰ.(3) The integrity of the ecosystem includes the vegetation integrity assessment, the benthic animal integrity and the environmental background quality assessment. The evaluation of biological integrity showed that Cuihu wetland has a low diversity and distribution of benthic animal and aquatic plant, and the soil is alkalescent, also the nitrogen and phosphorus content in water is a little high. The ecosystem health of district B (west part) is better than district A (east part). The highest level in district B was grade five, but the most regions of district A was grade two, and other regions were the lowest level. Mainly because district B has introduced more plants than district A, and the soil fertility in district B is much higher than district A. The introduced plants have a higher survival rate and a better growth in district B. A good developing environment has provided a good habitat for benthic animals, birds, fish and other animals. Therefore, biological integrity assessment shows that the benthic species and aquatic plant diversity and distribution were low.The results showed that Cuihu wetland maintained near-natural state. In order to achieve Cuihu wetland ecosystem healthy state that we should scientific monitor ecosystem health condition of Cuihu wetland regularly, and reinforce cultivation and breeding of aquatic plants, also use effective ways to improve water quality and reduce soil salinity.