BIODIVERSITY OF GROUND-DWELLING ANURAN

ABSTRACT

Anurans are the most diverse group of amphibians represented currently by 54 families, 460 genera and 7646 species worldwide. The tropical and sub-tropical regions of the world contain the highest diversity of these anurans. Anurans are delicate species and can be easily impacted by unnatural ecological, anthropological and agricultural practices. Therefore, studies on the biodiversity of anurans provides a comprehensive data of the extent and severity of anuran declines and can serve as a handy tool used by scientist to access the nature of the various ecosystems of the world. In this study, the diversity of ground-dwelling anurans in Okomu Oil Palm Plantation was studied over a period of three months using the Visual and Acoustic Encounter location (VAES) methods. A total of 64 ground-dwelling anurans specimens from 6 families, 6 genera and 10 species were caught. These include Sclerophrys maculata, Hoplobatrachus occipitalis, Hemisus marmoratus, Kassina senegalensis, Silurana tropicalis, Ptychadena bibroni, Ptychadena longirostris, Ptychadena mascareniensis, Ptychadena oxyrynchus and Ptychadena pumilio respectively. Sclerophrys maculata had the highest percentage occurrence (35.94%), followed by Hoplobatrachus occipitalis (18.75%). K. senegalensis, P. mascareniensis and P. pumilio had lower percentage occurrence (1.56%) each. A total of 19 (29.69%) males and 45 (70.31%) females were caught in this study. The record in this study compared favourably with two other studies which reported five species of ground-dwelling anurans each from urban and peri-urban locations of Benin City with Sorenson’s index value of 66.67%. These were H. occipitalis, P. bibroni, P. mascareniensis, P. oxyrynchus and P.pumilio. This is due to ecological similarities and geographical proximity between the three studies location. Presence of these species, which are usually associated with disturbed habitats shows that the current study location might be experiencing disturbance due to the intense agricultural activities. This study reinforces the need for a continuous study on anuran diversity as a way to constantly monitor and keep in check their rate of decline.