Assessment of Biodiversity and Conservation Value of Secondary Forests in Ondo State, South West Nigeria

This study assesses the biodiversity and conservation value of secondary forests of different ages and management histories in Ondo State, located in Nigeria's South West geopolitical zone, to inform policy on secondary forest protection. Secondary forests are increasingly recognised as important biodiversity refugia as primary forest continues to decline, but their conservation value relative to primary forest remains underquantified for West African contexts. Using a stratified design, three age classes of secondary forest (5 to 10 years, 11 to 20 years, and greater than 20 years) and one primary forest reference site were surveyed across four local government areas in Ondo North and South senatorial districts. Standardised transect and point count surveys were conducted for birds, and pitfall and hand sampling were used for herpetofauna and invertebrates. Similarity analyses, conservation species richness, and functional trait diversity were compared across age classes. Bird species richness increased significantly with secondary forest age, with greater than 20-year secondary forests retaining 82 percent of primary forest bird species richness. Several forest-specialist bird species and all amphibian forest specialists were restricted to primary and old secondary forest. Invertebrate functional diversity was lowest in young secondary forest but recovered substantially in old secondary patches. The study recommends legal protection of secondary forests above 20 years old in Ondo State under the state's forest reserve network and advocates a state-level forest age mapping exercise to prioritise conservation investment. Keywords: secondary forests, biodiversity, conservation value, Ondo State, forest recovery.