Effect of Urbanisation on Amphibian Diversity and Abundance in Ibadan Metropolis, Oyo State, South West Nigeria

Amphibians are among the most globally threatened vertebrate groups, with urban expansion identified as a major driver of habitat loss and population decline. This study evaluated the effect of urbanisation on amphibian diversity and abundance across an urban gradient in Ibadan metropolis, Oyo State. Sampling sites were categorised into three urbanisation levels: high, intermediate, and low, based on impervious surface cover and green space availability. Amphibians were surveyed using visual encounter surveys, acoustic monitoring, and drift fence arrays with pitfall traps during wet and dry seasons. Results revealed a clear decline in species richness and abundance with increasing urbanisation intensity. High-urbanisation sites harboured fewer than four species, dominated by the West African common toad, while low-urbanisation peri-urban sites supported up to eleven species, including several Forest-dependent anurans. Breeding habitat availability, particularly the presence of unpolluted standing water bodies and intact riparian strips, was strongly correlated with amphibian diversity. Road mortality was documented as a significant additional stressor in heavily trafficked urban zones. Findings support the conservation value of retaining and restoring vegetated drainage channels, urban wetlands, and green corridors to buffer amphibian populations from the negative effects of urban expansion in South West Nigeria. Keywords: amphibian diversity, urbanisation, Ibadan, habitat gradient, South West Nigeria.