Plant Diversity in the Guinea Savanna Agroecological Zone in Makurdi, North Central Nigeria

Background and Objective: Species diversity has been greatly reduced due to climate change leading to habitat loss and anthropogenic disturbances. Ecosystem degradation is known to affect plant diversity, hence the study assessed plant diversity in three ecosystems (grazing, riparian and plantation ecosystems) in Kwaghtamen Village, Makurdi Local Government Area of Benue State, Nigeria. Materials and Methods: In each ecosystem, 7 randomly sampled plots of 100×100 m were mapped, using line transect and all trees and shrubs were counted in each of the plots, collection of litter was done following standard practices (I m² quadrats). Data were collected on trees, grasses, herbs and litter. Plants were identified while type specimens were prepared following standard herbarium practices. Results: The relative frequency, density and important value indices varied with species and ecosystem types. Khaya senegalensis, Dialium guineense and Gmelina arboreawere the most dominant species. The species richness in ecosystems ranged between 28 and 7 (in riparian and plantation ecosystems). Tree diversity index followed in the order H = 3.22 (riparian), H = 2.78 (grazing) and H = 1.95 (plantation), while herbs and litter diversity were highest in grazing ( H= 4.0) and riparian (H = 2.8) ecosystems, respectively. Conclusion: This report has provided baseline information on plant species diversity in terms of distribution and richness in the three ecosystems studied. Efforts should be put in place to maintain these ecosystems, improve their plant diversity, sustainably utilize matured species of high population and conserve those with low populations as reported.