Species diversity and successional dynamics in the secondary forest of Obafemi Awolowo University Biological Gardens Ile-Ife, Nigeria

Abstract

Forests worldwide are being continuously disturbed by human activities and natural events, and tropical rainforest disturbance is specifically pronounced as indicated by its low biodiversity status. This study examined the floristic composition, species diversity and evenness in seven sample plots (100, 200, 400 and 2500 m2) in a secondary forest of different ages in the Biological Gardens of the Obafemi Awolowo University, Ile-Ife. The aim of this study was to determine changes in these parameters with succession. In each sample plot, all vascular plant species were accounted for and enumerated. The data collected were used to establish the floristic composition, density, diversity and evenness of plant species in the forest. There were 85 woody species (69%), 3 grass species (2%), 13 forb species (11%) and 21 climber species (17%) in the forest. These concern 113 genera and 52 families. The number of woody species in the plots varied with the age of the plots, however, there were no clear trends in the density and diversity of species with plot age. The forest was dominated by early successional species (50%) against the 33% contributed by the late successional species. Also, the youngest plot (Plot I) was dominated by early successional species while the older plots were dominated by a mixture of both early and late successional species. The similarity between plots during succession in the tropical forest was higher between plots of the same age. Also, this study showed that because of the directional pattern of succession, the species that converge to make up the diversity of forest of ages under consideration may be predictive of its recovery.

Keywords

• diversity
• evenness
• plant succession
• secondary forest
• similarity
• successional species