The First & Second Level Aquatic Ecofunctional Zoning Liao River Basin
|Keywords||Liao river basin aquatic ecoregion delineation indicators canonical correspondence analysis cluster analysis|
Aquatic ecological function regions at watershed scale can offer an important foundation for water environmental management as taking the objective from the water quality to aquatic eco-health. In order to reflect spatial differentiation of the natural characeristics of Liao River basin on a large scale, this work make use of Canonical Correlation Analysis (CAA) to analyze the correlation between the ratio of ratio of mean annual precipitation and annual mean temperature, hydrogeologic and water environmental factors, and aquatic organisms. The results showed that runoff depth, hydrogeology, normalized difference vegetation index (NDVI), digital elevation model (DEM) are the main factors for first aquatic ecological function zoning in Liao River basin. Indicator system and methodology of delineation of watershed has also been established. Liao River basin can be divided into 4 Grade I aquatic eco-regions, which locate in the upper reaches and middle reaches of West Liao river, Liao river plain and the upper reaches of Hun river and Liao river. All the aquatic eco-regions has significant relationship to the results of fish species cluster analysis. The result offers technologic support and scientific basis for ecological management of Liao river basin as well as the national aquatic ecological function regions at watershed scale.The second level aquatic ecological function regions at watershed scale aims to reveal the relationship between natural elements and aquatic ecosystem characteristics. In order to reflect differentiation of the natural characteristics of Liao River Basin on a middle scale, this work, based on the first level aquatic eco-functional zoning of Liao River basin, make use of Canonical Correlation Analysis (CAA) to analyze the correlation between amount of mean years annual precipitation, perennial mean temperature ,geomorphic type, the soil type, vegetation form, land utilization, aspect and slope. At last, amount of mean years annual precipitation, the soil type, vegetation form, land utilization are selected as the main factors of second aquatic ecological function regions in the Liao River Basin. The major content and criteria using in classification are identified and characteristics indicators for different ecoregion have been proposed. Thus indicator system and methodology of delineation of watershed has been established. Finally Liao River basin is divided into 15 GradeⅡregions. The result offers technology support and scientific basis for formulating the National Aquatic ecological function regions at watershed scale.