Health Evaluation Of Aquatic Ecosystem In Taiyangshan Wetland

11 sampling points were set up in the West Lake District,South Lake District,Little South Lake District,and East Lake District of the Taiyangshang National Wetland Park,based on the data of the water environment and aquatic biological factors of the Park in April,July,October 2019,and January 2020 to ascertain the health status of the aquatic ecosystem.Water quality was evaluated by the single-factor pollution index method,Nemeiro comprehensive pollution index method,and comprehensive nutritional status index method.Biological water quality was evaluated by Shannon-Weiner index,Margale index,Pielou index.Water environment and aquatic biological factors were screened through principal component analysis,and the aquatic ecosystem health evaluation index system was constructed,index weights were determined by analytic hierarchy process and entropy method,the health level of the aquatic ecosystem of the Taiyangshang wetland was evaluated by the gray correlation method and the fuzzy comprehensive evaluation method to provide a scientific basis for the ecological protection and restoration of the Taiyangshang National Wetland Park.The research results obtained in this paper mainly include:(1)Through analyzing the characteristics of the temporal and spatial changes of water environmental factors,the overall seasonal changes are not obvious,and the water body is in an alkaline state;there is little difference in the temporal and spatial changes of the four lakes of DO and TP;the highest value of BOD5 is in April,and the lowest value is in July;The content of CODMn and CODcr in East Lake is the highest;the content of TN in Little South Lake is the highest;NH3-N is the smallest in October;the content of Hg is the highest in January,and the content is lower in April and July;the content of Cu and Zn is the highest in the East Lake.According to the analysis of the single factor pollution index method,the Taiyangshang Wetland showed serious organic pollution as a whole,which is classified as Grade V water;according to the analysis of the comprehensive pollution index method,the overall pollution is pollution,West Lake District is pollution,South Lake District is pollution,Little South Lake District is pollution,and East Lake is moderately polluted;according to the analysis of the comprehensive nutritional status index method,the overall eutrophication is mild,the West Lake District is mildly eutrophic,South Lake District is moderately eutrophic,Little South Lake District is mildly eutrophic,and East Lake District is mildly eutrophic.(2)A total of 46 species of phytoplankton are detected in Taiyangshang National Wetland Park,belonging to 38 genera in 5 phyla;Shannon-Wiener index ranged from 1.718 to 3.990,with an average of 2.967,and the water body evaluation result is β-medium pollution;The Margalef index varies from 0.669 to 2.809,with an average of 1.542,and the water body evaluation result is α-medium pollution;the Pielou index is from 0.800 to 0.934,with an average of 0.891,and the water body evaluation result is clean.A total of 23 species of zooplankton are detected;the Shannon-Wiener index varies from 0 to 1.885,with an average of 1.216,and the water body evaluation result is α-medium pollution;the Margalef index varies from 0 to 1.613,with an average of 0.978,water body evaluation The result is heavy pollution;the Pielou index varies from 0 to 0.347,with an average of 0.203,and the water body evaluation result is heavy pollution.A total of 9 species of benthic animals are detected,belonging to 3 phyla and 6 classes;Shannon-Wiener index ranged from 0 to 0.617,with an average of 0.178.The water body evaluation result is heavy pollution;the Margalef index ranged from 0 to 0.55.The average is 0.156;the Pielou index is between 0 and 0.968,and the average is 0.246.Based on the results of biological assessment of water quality based on 3 biodiversity indicators,the water body of the Taiyangshang wetland is generally moderately polluted.(3)BOD5,TN,TP,NH3-N,CODMn,chl.a,Hg,Cu,Zn,phytoplankton S,zooplankton S,benthos S,phytoplankton H’,Fourteen indicators such as benthic animals H ’ constitute the index system for the health evaluation of the aquatic ecosystem of the Taiyangshang Wetland Park.The weights of the indicators are determined by the analytic hierarchy process and the entropy method,and the health assessment of aquatic ecosystems is carried out using grey correlation method and fuzzy comprehensive evaluation method.The results show that under the weight of the analytic hierarchy process,the health status of the aquatic ecosystem in Taiyangshang Park is evaluated as sub-healthy by the gray correlation method,and the West Lake,Little South Lake,and East Lake areas were unhealthy,and the comprehensive evaluation results are unhealthy;The fuzzy comprehensive evaluation method evaluated the West Lake District,South Lake District,Little South Lake District,and East Lake District as morbidity,and the comprehensive evaluation result is morbidity.Under the entropy method,the South Lake District is evaluated as very healthy by the gray correlation method,the West Lake District,Little South Lake District,and the East Lake District are unhealthy,and the comprehensive evaluation result is ill;the West Lake District is evaluated as unhealthy by the fuzzy comprehensive evaluation method.South Lake District is very healthy,Little South Lake District and East Lake District are morbid,and the comprehensive evaluation result is morbid.The health of the Taiyangshang wetland is not optimistic,and it is urgent to take scientific and effective measures for treatment and restoration.