Assessment of Tree Species Composition in the Riparian Axis of River Wupa, AMAC, Abuja

Résumé

The floristic assessment at low altitudes and its sequential characteristics are still very scanty to guarantee the global cross-biome comparisons. The study is aimed at assessing the richness and characteristics of trees species along River Wupa, with the view of establishing a baseline for interpretation of temporal changes of vegetation with particular reference to the Guinea Savanna Eco-zone in the FCC. The study is anchored on the quantitative research design. Investigation of tree stands was conducted mid-way of River Wupa along Jabi District due to its characteristic’s nature of luxuriant riparian vegetation. Three riparian micro-habitats were selected; line transect method was purposively used to examine species richness, density, and tree stand. The study adopts the Simpson index of diversity, Menhinick index of species richness. Philips method of species density and Newton’s formula for tree volume equation were used as three transect plot of 2m width by 50m length were delineated for vegetation studies. The analysis of variance (ANOVA) test was used to investigate the study hypothesis. The study revealed that Afzelia Africana and Ficus platyphylla were the dominant riparian tree species, while Parkia biglobosa was recorded as the least tree species in the riparian zone of River Wupa. Dominant shrub species along River Wupa were Anogeissu leiocarpus and Ceiba pentandra. Tree species richness along sampled transect shows that transect 1 have more species richness (2.04) to the ratio of tree density than transect 2 and 3 (1.68), indicating decrease in tree species richness down the river channel. In contrast, shrub species richness shows increase downstream the river Wupa. This indicates increase in tree volume downstream. The P value (0.004) of the ANOVA test indicates significant differences in the mean value of tree stands along transects. In contrast, the there was no significant difference in the occurrences of shrub along transects given the p value of 0.007. The study concludes that there is disparity in the composition and distribution of tree species along the riparian zones of River Wupa, as such recommends among others that; the current conservation principles employed in the form of plant gardening along River Wupa should be sustained.