Odonata assemblages along an anthropogenic disturbance gradient in Ghana’s Eastern Region

We assessed the effects of different levels of anthropogenic disturbance on Odonata species richness and assemblage composition in four different habitats in Ghana: mining sites, agricultural fields, human settlements, and primary forest habitat. A total of 992 individual adult Odonata representing 51 species (20 Zygoptera, 31 Anisoptera) in six families were recorded from 16 sites across these habitats. A majority of species (75%) recorded across all sites were previously classified as habitat generalists, while 20% represented specialists. The human settlement habitat exhibited the overall highest Odonata
abundance (302 individuals), whereas the greatest species diversity was observed in the mining sites (D = 4.59). Agricultural fields had lowest abundance (n = 196 individuals), while primary forest sites exhibited the lowest diversity (D = 2.75), although these differences were not statistically significant. There was also no significant difference in adult Odonata richness D (F3,59.72 = 2.48, p = 0.07) among habitats. However, species composition differed significantly among the various habitats (ANOSIM: global R = 0.73, p = 0.001). A canonical correspondence analysis revealed that river flow rate, percentage of canopy cover and channel width were the key factors influencing Odonata assemblages. Generalist and heliophilic dragonflies dominated in human-altered habitats, while the matured
forest habitat included more specialists and stenotopic damselflies. The results suggest that specialist dragonflies can be used as freshwater habitat quality indicators, and their habitat requirements also support the need to maintain the remnant primary forest in the East Akim District.