Species density and diversity along geomorphic gradient in Gashaka-Gumti National Park (GGNP), Nigeria

The relevance of geomorphic forms to the conservation and protection of plant species and their territorial habitats in the Gashaka-Gumti National Park (GGNP) Nigeria was examined. The study analyzed and stratified the geomorphic features of the Park and observed species types, density and diversity distribution pattern. The variation between the landscape features and species distribution were investigated at 0.095% test level. Remotely acquired data, field investigation, Geographical Information System (GIS), and statistical approaches were adopted for the study. Data was collected on morphologic form, altitude, gradient, soil types and physical properties, species types, density and diversity from 103 units of 625m2 quadrants. Results of the analysis show low species densities of 16, 14 with corresponding low diversities of 3, 3, per 625m2 on high altitudes whereas high densities of 60, 55 and corresponding high diversities of 11, 6 exist on middle altitudes. The plains and the riparian areas have mean density of 47 and corresponding diversity of 10 per 625m2. Uapaka togoensis, Crossopteryx februfuga, Brachystigia eurycoma Andria enermis are some of the species within low altitude stratum (240-599m). The middle strata 600-959m and 960-1319m are characterized by species such as Danielia oloveri, Hymonocadia acida, Terminalia glaucocens while at the upper strata (1320- 1679 and 1680-1885) Combrutum spp, Entanda africana, and Lanea shamperi are the notable examples. Assessment of the physical features and species variation between geomorphic strata variables revealed (except for gradient), significant variation. The 'F' values show F = 27.87 altitude value, F= 4.32 for gradient, F= 4.80 for density and F= 9.13 for diversity. Variation in soil properties, altitude, hydrology and slope gradient in order of importance were noted as the causal factors for the observed variation in species distribution.