Abstract

Adequate ecological information on forest status is essential for informed management decisions. This study assessed tree species diversity in Omo Biosphere Reserve and the International Institute of Tropical Agriculture (IITA) Forest in Ogun and Oyo States respectively. A systematic line transect method was used to establish twelve (12) sample plots (50 m × 50 m) in each forest. Trees with diameter at breast height (DBH) (1.3 m) of ≥10 cm were identified and measured in each plot for density, height, dbh and frequency. Detrended Correspondence Analysis (DCA), along with similarity and diversity indices, were applied using PAST software (version 3.0) to analyze the data. A total of 427 trees representing 57 species across 22 families were recorded in Omo, while 301 trees comprising 54 species and 22 families were documented in IITA. Euphorbiaceae (9 species), Apocynaceae and Meliaceae (5 species each) were the dominant families in Omo, while Fabaceae and Moraceae (8 species each) were the dominant families in IITA. Celtis zenkeri and Diospyros dendo had the highest frequency (92 %) each in Omo while Funtunmia elastica and Elaeis guineensis had the highest frequency of 90 % and 80 % respectively in IITA. Simpson’s species similarity and diversity indices for all the plots in Omo ranged from 0 – 77 % and 64 – 93 % respectively while for all the plots in IITA ranged from 9 – 62 % and 78 – 93 % respectively. Dominance value for all the plots in Omo ranged from 0.07 – 0.36 while in IITA ranged from 0.07 – 0.22. High eigen value 116.50 % and 82.98 % in Omo and IITA respectively indicates a stable environment and nearly all the species were found on the positive side of the quadrant which implies high interaction within the sites. In conclusion, this study demonstrated that natural regeneration could be an effective strategy for restoration of tropical tree species.

Keywords: Tropical forest, Biodiversity, Conservation, Natural regeneration, Ecology, Floristic composition