Woody tree components of the agricultural landscape play diverse roles in the improvement of agricultural productivity, maintenance of the agro ecosystem stability and improvement of livelihood of the dwellers of the rural communities. An understanding of the diversity of woody tree species on agricultural landscapes is crucial to the landscape approach to woody tree species biodiversity conservation. This study was carried out to investigate the diversity of woody tree species in agricultural landscapes of Ijebu North Local government Area (LGA), Ogun State, Nigeria. Data was collected on 0.06ha for each of the identified agricultural landscapes using purposive and simple random sampling. All woody tree species with DBH ≥2cm were identified. Shannon Weiner, Margalef and Pielou’s indices and Sorensen’s similarity coefficient (Ss) were used to measure the diversity of woody tree species in each farming landscape. Cash crop plantation has the highest Shannon index value (2.986) and Margalef value (7.016), farm fallow has the highest density of woody tree species (925 trees/ha) and evenness index (0.796). Woody tree species are significant component of agroecosystems in Ijebu North LGA and farmlands in the area have great potential for conservation of woody tree species diversity in the humid lowland zone of Southwestern Nigeria. It is recommended that the conservation potential of agricultural landscapes most especially the cash crop plantations of Ijebu North LGA should be harnessed and on-farm trees should be included in biodiversity conservation and sustainable management programmes.
Key Words: Agroforestry, Biodiversity, On farm trees, Shannon Weiner index