ASSESSMENT OF ABUNDANCE AND DISTRIBUTION PATTERN OF Terminalia SPECIES IN OLUWA FOREST, SOUTHWESTERN NIGERIA

Abstract

The abundance and diversity pattern of Terminalia species in Oluwa forest reserve was assessed in the present study. The aim of this work was to analyze the abundance and distribution pattern of Terminalia species in Oluwa forest reserve for conservation purpose, the influence of topography of the study area on Terminalia species diversity was also considered. Complete enumeration of the Natural forest was carried out to determine the varieties of Terminalia species in the study site. In all, two variety of Terminalia (Terminalia superba and Terminalia ivorensis) were identified. The G.P.S coordinate of species location was overlaid on the topography data (Elevation, Slope, Aspect and Hillshade), the area with low elevation, and low slope, high hillshde, and the west aspect showed maximum species abundance (richness). The diversity index and evenness (Shannon index of diversity) of Terminalia species from the Natural forest (Tropical rain forest) was calculated and the result implies that Terminalia species diversity/abundance is low in the study site. It was observed that the spatial distribution and relative abundance of Terminalia species was influenced by topographic factors. Despite the limited range of altitudinal variation (399 m), species richness increases with elevation. This work has provided evidence of variability in Terminalia species composition, richness and diversity across the topographic gradient in Oluwa forest, Ondo State, Nigeria. The information could be crucial for monitoring and providing conservative measure for management of species sustainability. A future study would be required to isolate proximate factors of tree species distribution in the study area.