Herpetological surveys of south-western and south-eastern regions of Nigeria

Abstract

The herpetofauna of part of the south-western (Lagos, Ogun and Oyo States) and south-eastern (Cross River State) regions were investigated. Specimens were located opportunistically during visual surveys. Both regions fall in the tropical zone, and the south-western region surveyed, was mostly lowland, degraded forests (mostly secondary) and savanna. The southeastern regions surveyed were of primary forests, montane, sub-montane and plateau habitats. A total of 35-38 amphibian species were recorded in south-western Nigeria and over 49 species in the south-eastern region. Higher amphibian diversity was observed in the south-eastern region due to the diversity of habitat types. The difference in species diversity was due to the presence of Werneria mertensiana, Didynamipus sjoskedti, Cardioglossa gracilis, C. leucomystax, Astylosternus batesi, A. djedematus, A. montanus, Amietophrynus superciliaris, Petropedetes johnstoni, Leptodactylodon bicolor, L. polycanthus among others, regarded as forest and montane species. A few farm-bush and savanna species were also observed and they include Haplobatrachus occipitalis, Amietophrynus maculatus, Phrynobatrachus accraensis, Arthroleptis variabilis and Silurana tropicalis which may indicate that the primary forests are being degraded, hence the emergence of these invasive species. The lower amphibian diversity observed in the south-western region is believed to have resulted from the high amount of degradation and conversion of the natural forests into the impoverished faunal region. Future intensive surveys of both regions especially the degraded areas of the southeastern region would undoubtly reveal existing species not encountered in this study or even undescribed species.

Keywords: herpetofauna, amphibian diversity, south-western region, south-eastern region, invasive species.