Analysis of the Diversity of Odonata in the Chaobai River Basin and Its Influencing Factors

The Chaobai River is an important water source of Beijing.Understanding the current status of Odonata (hereinafter referred to as dragonfly) diversity and its influencing factors is crucial for the local ecological environmental protection.Based on the results of two-phase dragonfly surveys conducted at 31 sites in the Chaobai River Basin during the summer and autumn of 2024,the species composition,faunal distribution,and spatiotemporal distribution of dragonflies were analyzed,and the factors influencing the diversity of dragonflies in the Chaobai River were identified.The results show that: ① A total of 48 dragonfly species from 33 genera and 9 families were recorded during the surveys,accounting for 75% of Beijing's historical records.The regional dragonfly community was dominated by the suborder Anisoptera and characterized by a few dominant species,with Matrona basilaris,being the common dominant species in both summer and autumn.In terms of faunal distribution,10.41% were widespread species,including Anax nigrofasciatus,Anax julius,Pantala flavescens and Crocothemis servilia.② The abundance and species richness of dragonflies in the Chaobai River showed significant spatiotemporal variations.The dragonfly abundance and species richness were both higher in summer,while in autumn,the abundance declined by approximately two-thirds and species richness decreased by one-third.Both abundance and species richness were significantly higher in the wild gorge sections than in the urban plain sections (P<0.001).③ The abundance and species richness of dragonflies in the Chaobai River Basin were significantly positively correlated with aquatic vegetation richness (P<0.005),mainly with the species richness of submerged plants (P<0.001).Analysis of variance on dragonfly diversity between natural and artificial shorelines showed that dragonfly abundance was significantly higher along natural shorelines than along artificial shorelines (P<0.05),which may be due to the complex and diverse microhabitats and vegetation structures along natural shorelines,providing more favorable oviposition sites,habitats,and foraging opportunities for dragonflies.