earticle

영어

Tropical forests in Nigeria (such as Omo Biosphere Reserve, OBR) are rich in species diversity and play an essential role in conserving biodiversity and enriching livelihood. Despite numerous studies in OBR, the interconnected dynamics of forest structure, species diversity, and Above-Ground Biomass (AGB) across its distinct management zones remain understudied. This study examined the AGB, species diversity and diameter distribution across the three zones in Omo Biosphere Reserve, Nigeria. A line transect sampling design was employed, and all woody trees with diameter at breast height (DBH)≥10 cm were measured across zones. Tree parameters recorded included DBH, basal diameter, top diameter, and total height, while species-specific wood density values were obtained from the FAO wood density database. Diameter distributions were modeled using four probability density functions: Johnson (SB), Weibull (3P), Lognormal (3P), and Beta and they were ranked based on Kolmogorov Smirnov. Tree frequency per hectare (TF), Tree relative density (TRD), Tree Basal Area (TBA), Tree Relative Dominance (TRD), Shannon-Wiener Diversity (H’) and Family Important Value Indices (FVI) were used to estimate the species diversity, and Aboveground biomass (AGB) was estimated using the allometric model. The result revealed significant differences across the zones. The core zone had the highest biomass while the buffer zone exhibited slightly higher species diversity likely due to edge effects. Johnson SB provided the best fit for diameter distribution, capturing the inverse J-shaped pattern typical of regenerating tropical forests. Findings from this study gave insights that emphasize the importance of differentiated management zones within a biosphere reserve and the crucial zone of protected zone in biomass conservation. These insights support evidence-based strategies for enhancing biodiversity, improving carbon sequestration, and strengthening the ecological resilience of protected tropical forests.