| River is the link between land and ocean and it is also an important part of the biosphere material circulation. Its special habitat characteristics have created the diversity of its biological communities. River is the habitat of aquatic plants, benthos, plankton, amphibians and various kinds of fishes, so it provides very abundant fresh water resources for human. Therefore, more and more attention has been paid to the assessment of river ecosystem’s health.Physical, chemical and biological indicators can be used to evaluate the river ecosystem’s health.In recent years, most of studies have turned from the simple water quality survey to the adoption of biological indicators. One of the most widely used indicators is the biotic integrity index. The biological indicator of this method is numerous. We can choose fish, benthic invertebrates, adherent algae, plankton, higher vascular plants, microorganisms, etc. Most of the researches focus on the first three organisms, especially the fish according to the studies in our country and abroad countries. Fish was the first indicator species when the biotic integrity index was used to evaluate the river ecosystem’s health because of its advantage in assessment of river ecosystem’s health. The method based on the fish-index of biotic integrity becomes the most commonly used method to evaluate river ecosystem’s health in our country and abroad countries.Xiaoqing River is located in Shandong province. It originates from the springs in Jinan and flows eastward into the Bohai Sea. It is a river that has functions of releasing flood waters, shipping, irrigation, cultivation, etc. So, it used to provide a lot of water and fish resources for human in Shandong province. But, Xiaoqing River had been polluted from the mid of 1980s, so the government monitored the water quality of the Xiaoqing River regularly and took various methods on the ecological recovery in order to improve Xiaoqing River’s health.Previous studies about Xiaoqing River focused on physical or chemical indicators. While, this research referenced to indicators used in river ecosystem’s health assessment based on fish’s integrity in our country and abroad countries, and it considered actual situation of Xiaoqing River. We tried to set up an indicators system of biotic integrity based on fish (F-IBI), which is suitable for Xiaoqing River’s health assessment. And then we can use this F-IBI system to express the present condition of fish integrity of Xiaoqing River and evaluate Xiaoqing River ecosystem’s health. In addition, this research also analyzed the relationship between various physical or chemical factors and IBI at the same time, so we can find out the dominating or limiting factor which lead to present "healthy" or "unhealthy" state in different part of Xiaoqing River. This can provide a scientific basis to the reasonable utilization, pollution controlling and recovery protection of Xiaoqing River.This study utilized survey data which collected from the source to the estuary of Xiaoqing River in July and October in 2013. We combined indexes which had been revised by Karr with the actual fish composition characteristics of Xiaoqing River, and chose 23 candidate indicators belonging to five properties. Then we screened the 23 candidate indicators through three steps, and preliminary build an F-IBI system for Xiaoqing River. Following, we used the 1,3,5 assignment method and ratio method respectively to build fish integrity evaluation standard and then evaluate the heath of ecological environment of every different part of Xiaoqing River.The result showed that although the result of the 1,3,5 assignment method and the ratio method is not exactly the same, the trend is consistent. From source to estuary of main stream, the trend of healthy condition is "healthy"â†'"poor"â†' "healthy". Most points shown as "healthy" level are located in the upstream of Xiaoqing River while the point named Wangdao is at "very poor" level. The F-IBI value of estuary is higher because of the infusion of ocean fishes. The healthy condition of tributary is better than main stream.I also analyzed the correlation of F-IBI values and different physical or chemical factors using Pearson correlation analysis, and the result demonstrated that F-IBI value of ratio method negatively correlates with water ammonia nitrogen’s concentration. This illustrated that too high ammonia nitrogen concentration is a factor that influences the health of Xiaoqing River. |
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