12. Riparian Vegetation Along Nigeria Rivers: The River Ogun Example

The presence of vegetation along a stream has been shown to affect a variety of biotic and abiotic processes, resulting in complex effects on stream structure and water flow dynamics. The magnitude of these effects depends on the type of vegetation, its mechanical properties and density, as well as its spatial distribution. Across rivers draining Nigeria, the riparian composition varies significantly. The southern part of the country presents more luxuriant vegetation along river courses than the northern part. However, biodiversity along river courses in Nigeria presents a scenery that is attractive to view and also serves as economic gains for the local people. River Ogun, an alluvial example that is reported in this study, largely epitomizes the situation of riparian ecosystems in the humid tropics. Typically found along this alluvial stretch are woody plants and light forests which influence riverbank stability. Morphological features like sand bars, cut banks, oxbow lakes and braided channels that have been colonized by riparian species are prominent along the reach. The natural functioning of this riparian ecosystem has over time been disturbed by sand mining, plantation agriculture and arable crop farming.