Abstract:

Aims: Guangdong Province, located at the northern boundary of the tropical climatic zone, harbors exceptionally high biodiversity due to its warm, humid climate, complex terrain, and dense river networks. However, aquatic insects, especially Odonata, have been insufficiently surveyed compared with terrestrial taxa. This study aims to elucidate the species composition and zoogeographical characteristics of Odonata across Guangdong Province, and to identify the geographical patterns and key environmental drivers of their taxonomic diversity.

Methods: Redundancy analysis (RDA) combined with forward selection was used to identify key environmental variables associated with Odonata community structure. Subsequently, variation partitioning analysis (VPA) was applied to disentangle the relative contributions of climate, topography, and land-use factors to spatial variation in community composition.

Results: A total of 261 species (including subspecies), belonging to 115 genera and 19 families across two suborders, were recorded. Among them, 71 species (including subspecies) are endemic to China, representing 27.20% of the total richness. In terms of faunal composition, species with an Oriental distribution (restricted to the Oriental realm) predominate, comprising 199 species (including subspecies), followed by Palaearctic-Oriental species distributed across both realms, totaling 62 species (including subspecies). Regarding zoogeographical types, the South China Region-Central China Region type was most common (90 species; 34.48%), followed by the South China Region type (63 species; 24.14%). Spatial analyses identified the central and northern mountainous regions as diversity hotspots, with Longmen County (Huizhou) and Zengcheng District (Guangzhou) harboring 173 and 154 species (including subspecies), respectively. RDA revealed that mean annual temperature, precipitation seasonality, slope, farmland proportion, forest proportion, water-body proportion, and elevation range were the principal environmental factors shaping Odonata community structure. VPA showed that climate, topography, and land-use jointly explain spatial variation of community composition (20.00%), with climate uniquely contributing the highest independent fraction (8.00%).

Conclusion: This study provides the first systematic assessment of the faunal characteristics and geographical patterns of Odonata taxonomic diversity in Guangdong Province, identifying the key environmental drivers shaping community structure. The results fill a critical knowledge gap in aquatic insect diversity within the province and provide essential baseline information for faunal biogeography, biodiversity monitoring, conservation planning, and evaluation of management effectiveness.

Key words: aquatic insects, Odonata, South China region, species diversity, faunal composition