Abstract

Ecological diversity of herbaceous plants in Old Afaka forest reserve in Kaduna Northern Guinea Savanna   eco-region of Nigeria was studied. The study area was purposely divided into 4 main plots based on vegetation density and human interference. 50m x 100m plots were laid with 50m espacement between the plots. Line transect method was used in assessing the herbaceous vegetation. 3 main growth form (Shrub; Grasses and Sedges) were used to classify the herbaceous species for easy identification. Data collected were analysed using frequency distribution tables and percentages. Biodiversity indices were calculated using Shannon Weiner index; Simpson index; Margalef’s richness index and Pielous’s evenness index. The results revealed that there are 41 different species with Isoberlinia doka from shrub growth form having the highest occurrence (217) and highest percentage spread (32.7%) among all the species belonging into 24 families of which poaceae was the most dominant with 9 species belonging to the family these includes: Eragrotis spp. Paspalum orbiculae, Penisetum hordeides, Eragrotis trannula and so on in which the later had the highest percentage spread (13.3%.) Among the growth forms, shrubs are higher in the percentage spread (57.8%) than the grasses (35.0%) while the sedges are the least (7.2%). Order of percentage spread: Shrub > Grasses > Sedges. However, in terms of biodiversity indices: Shannon – Weiner index was found to be higher in grasses (0.37), lower in sedges (0.20) while, Simpson diversity index was higher in sedges (1.00) but lower in shrubs (0.67). Margalef’s richness was higher in shrubs (85.1) but lower in sedges (11.5). Lastly, the Pielous’ evenness shows higher index in grasses (0.061) but lower in sedges (0.043). Further research should be carried out in the reserve to promote the regeneration potentials of the diverse species of herbaceous plants.

Key Words: Biodiversity, Poaceae, Herbaceous, Growth forms, Regeneration