Biodiversity assessment and species distribution of wild animals across ecological zones in Nigeria

Biodiversity assessment provides critical insights into species distribution and ecosystem integrity, particularly in regions experiencing increasing anthropogenic pressure. This study investigated the distribution and diversity of wild animal species across three ecological zones of Nigeria Akwa Ibom (South-South), Nasarawa (North-Central) and Oyo (South-West). Data were collected from local markets and hunters’ catches, and analyzed using descriptive statistics, biodiversity indices and inferential statistics. Species richness and diversity were estimated through Shannon–Wiener and Simpson’s indices, while a Chi-square test of independence was employed to examine whether species distribution significantly differed across ecological zones. Symmetric measures, including Phi coefficient and Cramer’s V, were further applied to assess the strength of association between species occurrence and ecological zones. The results revealed marked differences in species distribution, with grasscutter (Thryonomys swinderianus), antelope (Cephalophus maxwellii and Tragelaphus spp.), and giant rat (Cricetomys gambianus) contributing the highest proportions across zones. Akwa Ibom exhibited the highest relative abundance, while Oyo showed comparatively lower diversity. Biodiversity indices confirmed moderate diversity across all zones, with the Shannon index values ranging from 1.75 to 2.10 and Simpson’s index indicating low dominance of individual species. The Chi-square test indicated that species distribution was not independent of ecological zones (p < 0.05), suggesting ecological and anthropogenic factors jointly shape wildlife occurrence. Symmetric measures showed a moderate association between species and zones, reinforcing the spatial influence on biodiversity composition. The study highlights the ecological importance of monitoring faunal distribution across heterogeneous landscapes. Findings provide baseline data for conservation planning and underscore the need for policies that integrate local hunting practices, habitat protection, and sustainable wildlife utilisation. Such evidence-based interventions are essential for balancing biodiversity conservation with rural livelihoods in Nigeria.