The Odonate fauna (Insecta: Odonata) of Belihuloya, southern intermediate zone of Sri Lanka: A preliminary assessment and conservation implications

Abstract

Belihuloya situated in a biogeographical transition zone in south-central Sri Lanka is being threatened by land-use changes. Establishing baseline biodiversity knowledge of an indicator taxon within this lesser explored area, the present study systematically assessed its Odonate fauna in different habitat types through a transect survey supplemented with incidental observations. Further, the morphology of larvae and exuvia of some Odonates were opportunistically documented from selected water bodies. Transect survey and opportunistic observations identified 36 species of Odonates (22 dragonflies and 14 damselflies) representing ten families, with ten Sri Lankan endemics. Four species of dragonflies and eight damselflies are nationally threatened, including critically endangered Elattoneura centralis and endangered Libellago greeni . The calculated species richness (R), Shannon-Wiener diversity (H’), evenness (E) and Simpson’s diversity (1/D) values were, 3.51, 2.40, 0.85 and 7.90 for dragonflies, and 2.85, 2.36, 0.92 and 8.68 for damselflies respectively, while two groups show vertical niche segregation. Low Odonate community similarity coefficients among habitat types indicate they are complementary for conservation planning. Out of ten Odonate species for which larval stages were recorded, the larval morphology of Anax indicus and Gynacantha dravida are described for the first time in Sri Lanka. Baseline data provided here are used for evidence-based conservation recommendations. • Odonate fauna from Belihuloya, Sri Lanka includes 36 species (22 in Anisoptera and 14 in Zygoptera). • This includes 12 nationally threatened species (2 critically endangered [CR], 1 endangered [EN] and 9 vulnerable [VU]). • The larval morphology of Anax indicus and Gynacantha dravida are described for the first time in Sri Lanka.