Effects of anthropogenic disturbances on adult Odonata fauna in Akure, south west Nigeria

Human activities such as deforestation, urbanization, industrialization, canalization, and water abstraction, negatively affect biodiversity. This study was carried out to determine the effect of anthropogenic activities on the composition, distribution, and abundance of Odonata of Akure South Local Government Area.

A total of 2376 Odonata individuals (1363 dragonflies and 1013 damselflies) in 6 families (Libellulidae, Ceonagrionidae, Calopterygidae, Platycnemididae, Chlorocyphidae) and Gomphidae, 19 genera and 36 species were recorded in this study. Pseudagrion ‘A’ kersteni (651) is the most frequent species followed closely by Trithemis arteriosa, they were found in all the sites, therefore are generalists. Eight species including Lestinogomphus minutus, Pantala flavescens, Copera sikassoensis, etc., are least represented in the study, they were made up of one individual each. Leo study site has the richest odonate fauna (Simpson dominance: 0.8497, Shannon–Wiener H_: 2.234 and Margalef: 3.021); while, the least was Oda (Simpson dominance: 0.7899 and Shannon Wiener H_: 1.932). The distribution of the species was highest at Oda (evenness E: 0.4931), followed closely by Leo (evenness E: 0.4916); while, Ijapo (evenness E: 0.3852) is the least.

The few stenotopic species and, proliferation of eurytopic species in the study sites proved that the sites are undergoing intense anthropogenic disturbance and conservation efforts must therefore be put in place to prevent the extinction of these species and their restoration in sites they were absent.