Slope Difference Of Diversity Of Aquatic Insects In Three Parallel Rivers Region And River Health Assessment

Exploring the spatial distribution pattern and driving factors of aquatic insect diversity is an important part of river ecological research.The Three Parallel Rivers region has rich diversity and unique valley topography,providing a suitable place for research.As an important part of freshwater ecosystem,aquatic insects are widely used in biodiversity related research due to their wide distribution,easy collection and sensitivity to pollutants.This study explored the slope aspect differences of aquatic insect diversity in different dimensions in the Three Parallel Rivers region of northwest Yunnan,and analyzed the general characteristics and protection significance of the species causing the differences.After that,the research analyzed and summarized the environmental factors that have a greater impact on aquatic insects,and took Gaoligong Mountain as an example to apply the relevant conclusions to the river ecosystem health assessment.The results are as follows:1.The difference between the east and west slopes of aquatic insect diversity in the study area is mainly reflected in the difference of taxonomic groups.Specifically,the west slopes of Biluo and Cangshan areas have more abundant taxonomic groups,and the two slopes of Lushui area are close.The altitude patterns of species richness in the three regions are similar in different slope directions,but there are differences among the regions.The taxonomic diversity of the three regions has no obvious elevation pattern.The differences of taxonomic groups in the three regions have already appeared at higher taxonomic levels(such as order level and family level).The species with different slope directions in the three areas are all rare species.2.There is no significant difference in the physical and chemical factors of local water environment between east and west slopes in the three parallel rivers region.The diversity of aquatic insects on the western slope was only affected by a few environmental physical and chemical factors,and the influence was weak,while the diversity of aquatic insects on the eastern slope was affected by several environmental physical and chemical factors,and the influence was strong.Environmental factors such as total nitrogen,phosphate,p H,chlorophyll and so on have important contributions to the change of biodiversity.In addition,dissolved oxygen,as a limiting factor,affects the distribution characteristics of benthic macroinvertebrate diversity on the eastern slope,characterized by its contribution to species richness and species evenness,which is a common phenomenon in areas with large altitude span.3.The species that contribute more to the difference of aquatic insect community structure in each area are common species,and the number of individuals of the first few species that contribute more is also the first few in the corresponding community.The removal of rare species significantly reduced the species richness and total taxonomic diversity of the corresponding communities,especially the results of taxonomic structure correlation calculation.4.Each area has high biodiversity.The overall water quality in the study area is good,with most sample points meeting the Class Ⅰ or Ⅱ water standards,some sample points meeting the Class Ⅲ water standards,and a few other sample points meeting the Class Ⅳ water standards.The habitat environment quality in the Lushui area is good,with an average QHEI score of 180.36.The comprehensive evaluation results show that the sample points all belong to the health level,and the overall river ecosystem is in a healthy state。 But human activities have affected the health of a few river sections.The human activities that mainly affect the river health include agricultural and animal husbandry activities,river bank and riverbed hardening,damming,water intake,etc.In view of the increasing human interference,it is recommended to carry out regular river health assessment for relevant river sections,adjust the production and development activities of the river and riparian zone according to the assessment results,reduce unnecessary channelization,and establish buffer zones for vulnerable river sections to protect the aquatic biodiversity of the river and maintain the health of the river ecosystem.