Abstract:

Aims: Odonata are widely recognized as reliable bioindicators for evaluating aquatic-terrestrial ecosystem integrity. Their species diversity, community structure and population dynamics are closely correlated with regional ecological environment quality. Focusing on odonate diversity in Beijing, this study explored its spatio-temporal distribution patterns and identified the key environmental factors influencing their distribution, so as to provide a reference for insect biodiversity conservation and ecological habitat restoration in rapidly urbanizing areas. 

Methods: Based on systematic field surveys conducted across Beijing from 2020 to 2024 and valid citizen science observation data integrated from the GBIF database, we calculated and compared multiple biodiversity indices including the Shannon-Wiener diversity index, Simpson dominance index, Margalef richness index and Pielou evenness index of odonate communities. This study compared variations in odonate diversity across different seasons, elevation gradients, habitat types, water quality grades and human disturbance intensities. Furthermore, we analyzed the main environmental factors influencing Odonata distribution along urbanrural gradients. 

Results: A total of 67 Odonata species, belonging to 44 genera and 10 families, were recorded since 2020. Libellulidae, Coenagrionidae and Gomphidae were the dominant families, while Orthetrum and Sympetrum were the most speciose genera. Compared with historical records prior to 2010, the species composition and community structure of Odonata in Beijing have undergone considerable changes. Some historically recorded species were no longer detected, while several southern warm-adapted species were newly recorded in Beijing, which was closely associated with climate warming and urban wetland landscape reconstruction. The population status of Libellula angelina has improved substantially. Odonate species were predominantly active from June to August, and mainly distributed at elevations ranging from 200 to 1000 m. Urban green and blue spaces in the central city can maintain a certain level of odonate diversity. However, due to high urbanization and habitat homogenization, the community is dominated by ubiquitous generalist species, with low evenness. The zone between the Third and Fourth Ring Roads features scarce urban parks and intensive diverse human activities, serving as a relatively low-diversity area for odonates. Habitats beyond the Sixth Ring Road represent key areas for sustaining odonate diversity in Beijing, as they support the survival of relatively environmentally sensitive species. Several taxa, including species within Lestidae, the genus Somatochlora (Corduliidae), and Enallagma cyathigerum, exhibited strong indicator potential for water quality and anthropogenic disturbance, whereas species including Ophiogomphus spinicornis, Macromia beijingensis and Sympetrum croceolum showed high sensitivity to human impacts. Elevation, land use, fractional vegetation coverage, water quality, and human disturbance intensity are the main environmental factors affecting the distribution of Odonata in Beijing. Human disturbance intensity and water quality are the core environmental factors shaping common odonate community structure in Beijing. Along the urbanization gradient from the urban core to the rural periphery, the dominant drivers gradually shifted from human disturbance, land use and water quality toward natural factors such as elevation and fractional vegetation coverage. 

Conclusion: By revealing the driving mechanisms of Odonata distribution and the shifting characteristics of environmental factors along urbanization gradients, as well as identifying sensitive indicator species and conservation priority areas, this study recommends implementing zoning strategies in urban biodiversity conservation. Within the Sixth Ring Road, priority should be given to optimizing artificial vegetation configuration and improving habitat heterogeneity and water connectivity. Beyond the Sixth Ring Road, the protection of natural and semi-natural habitats should be strengthened, and a long-term monitoring system centered on indicator species should be established. This study clarifies the gradient differentiation mechanism of odonate community responses to urbanization, providing ecological references for the differentiated conservation and habitat management of odonate diversity in megacities.

Key words: Odonata, distribution pattern, urbanization gradient, environmental influencing factors, Beijing