Investigation And Health Assessment Of Hydrobiont Biodiversity In Wuliangsuhai

Aquatic biodiversity is a key factor in maintaining the balance and stability of lake ecosystem,which plays an important role in lake ecological restoration and health assessment.In this study,selected plankton,benthic animals,aquatic plants and fish as the research objects in Wuliangsuhai Lake.Analysing the species,number and diversity of aquatic organisms in detail.And using analytic hierarchy process carried out the health assessment of Wuliangsu marine aquatic ecosystem.The specific research results are as follows:There are 144 species in 8 phyla of phytoplankton in Wuliangsuhai.In April(spring)and July(summer),the average abundance of each sample point in those two seasons is phytoplankton is 2.481×105cell/L.From the results of Shannon index,Margalef index and Pielou index,the phytoplankton diversity of Wuliangsuhai is very rich in spring and summer.There are 62 species of zooplankton in Wuliangsuhai.Among them,Rotifer and Protozoan are the dominant phylum,and the other two types are relatively small.The average abundance of Macrozooplankton is 1342.17ind./L,the average abundance of Protozoa is 3.930×104ind./L,and the average biomass is 6.856mg/L,There are 3 orders,7 families and 9 species of zoobenthos in Wuliangsuhai.The Shannon Wiener index,Margalef index and Pielou evenness index of zoobenthos were 2.214,1.209 and 0.698 respectively,and their diversity was at a general level.Wuliangsuhai aquatic plant can be roughly divided into three types:emergent plant,submerged plant and floating plant.There are 6 families,6 genera and 11 species of macrophytes.More than 50%of the lake is covered by reed,mainly distributed in the middle,the west and the north of the lake.A total of 15 species,7 families and 4 orders,were found in Wuliangsuhai.Compared with the historical data which in 1980,the fish population of Wuliangsuhai is seriously degraded,and the species and quantity are reduced compared with the previous,which shows that the change of ecological environment has affected the survival of some fish populations.This paper selects five indexes with the ability to represent the current state of lake as the evaluation criteria,namely,fish retention index and number of phytoplankton,zooplankton loss index,benthic index of biological integrity,and coverage index of macrophytes.The weight of each index layer was determined as 0.360,0.219,0.219,0.123 and 0.079 by hierarchical analysis methods.The result show that fish had the greatest impact on the aquatic biodiversity of Wuliangsuhai.According to the technical specifications,all indicators were scored,and the final score of Wuliangsuhai aquatic biodiversity system was 77.10,which belongs to the health level.