Study On The Evaluation Of The Ecosystem Health Of The Weihe River Basin

The river ecosystem plays an important role in the material energy cycle of nature and the survival and development of human beings.With the development of human productivity,the impact of human beings on the environment has increased,and the extent of rivers being disturbed by human activities has increased.The health problems of rivers have become increasingly apparent and have attracted worldwide attention.From the perspective of protecting the river ecosystem,establishing a river health evaluation system,paying attention to the multi-faceted relationship between the river and its ecosystem,accurately and effectively evaluating the water environment health of the river basin,has important practical significance for ensuring the ecological safety of the river.This paper takes the Weihe River Basin as the research object,based on the 2017 Weihe River Basin Ecological Environment Survey,and constructs a Weihe River Basin ecosystem health evaluation system and method covering aquatic organisms,habitat structure,land ecological pattern,ecological function and ecological pressure.And use this comprehensive evaluation index system to evaluate the ecosystem health of the Weihe River Basin.The main results of this paper are as follows:1)According to the understanding of the concept of river ecosystem health,a river ecosystem health evaluation index system including land ecosystem and water ecosystem was constructed.The land ecosystem index includes forest coverage rate,important habitat conservation rate,water conservation function,population density and construction land proportion.Indicators of aquatic ecosystem include river connectivity rate,water quality,fish biological integrity,macroinvertebrate integrity,zooplankton diversity and phytoplankton diversity.And entropy weight method was adopted to assign weight to each index,the comprehensive evaluation method for ecosystem health in Weihe River Basin was established.2)The data of land use,land cover and social economy in the Weihe River Basin were collected,and the field survey and aquatic biological collection were carried out at49 points in the whole basin.After further processing of the obtained data,the ecosystem health of the Weihe River Basin was evaluated.The comprehensive evaluation results of ecosystem health in the Weihe River Basin were as follows: the comprehensive evaluation score of ecosystem health in the main stream of Weihe River was 55.15;The comprehensive evaluation score of ecosystem health in Jinghe River was 58.81.The comprehensive evaluation score of ecosystem health of Beiluo River was 57.11,and the health level of Beiluo River was "general".3)The spatial distribution characteristics of the ecological health evaluation indexes in the Weihe River Basin were analyzed.It was found that the evaluation results of different indexes on the ecosystem health of the watershed were significantly different,and the same index also had obvious differences in different evaluation units.However,according to the comprehensive index of ecosystem health assessment in the Weihe River Basin,there was little difference in the ecosystem health status of each assessment unit in the Weihe River Basin,with scores ranging from 53 to 66.Except for the assessment result of the middle reaches of the Beiluo River Basin,the assessment result of the other assessment units was "general".4)Among the evaluation indexes,the water quality,fish biological integrity,macroinvertebrate integrity,zooplankton diversity,conservation rate of important habitat and population density score are the lowest,which reflects that the index of water ecosystem is the main factor affecting the ecosystem health of the Weihe River Basin.However,the assessment results of ecological health indicators based on different aquatic organisms were significantly different,indicating that the assessment results of a single biota were biased to the habitat suitability of the community.