Dickson Anoibi A. Matthew ^1* Samuel T. Osinubi ² Samuel T. Ivande ³ Soladoye B. Iwajomo ⁴ Ulf Ottosson ¹

• ¹ A.P. Leventis Ornithological Research Institute, Jos, Nigeria
• ² Percy FitzPatrick Institute of African Ornithology, Faculty of Science, University of Cape Town, Cape Town, Western Cape, South Africa
• ³ Department of Zoology, Faculty of Natural Sciences, University of Jos, Jos, Plateau, Nigeria
• ⁴ Department of Zoology, Faculty of Science, University of Lagos, Lagos, Nigeria

The rural-urban gradient serves as a valuable context for investigating the impact of urbanization on biodiversity. While previous studies have demonstrated shifts in bird communities along this gradient, our understanding of the specific impacts of individual urban components such as man-made physical structures and anthropogenic noise, remains limited, and more so, in Afro-tropical environments. Employing the point count method, we recorded birds and also determined the levels of anthropogenic noise and physical structures, across fifteen sites along the rural-urban gradient in the Jos Plateau, Nigeria. We then investigated variations in bird communities along the urbanization gradient and assessed the influence of the two urban components -anthropogenic noise and physical structures, on bird populations. Our findings revealed a decline in bird abundance and species richness along the urbanization gradient. Similarly, species common to all the urbanization categories (species present at least at one point in rural, suburban, and urban) also exhibited a decrease in abundance. The suburban area showed a greater similarity in bird community composition to the urban area than the rural area. Notably, as the level of urban development increased, numerous bird species associated with undisturbed sites gradually vanished. Both anthropogenic noise and physical structures exhibited significant negative effects on bird abundance and species richness. Interestingly, there was no evidence of interdependence between these urban components, suggesting that their impacts on bird communities were not contingent on each other. Anthropogenic noise had a significant negative effect on bird abundance and richness at all levels of physical structures. Overall, our research underscores the detrimental consequences of anthropogenic habitat modification, particularly the alteration of structural and acoustic properties, and emphasizes the importance of preserving undisturbed habitats and implementing ecologically mindful urban planning strategies to safeguard bird communities in the Afro-tropics.