Abstract

Okomu National Park and Okomu Forest Reserve were established to protect the rich flora and fauna resources. Studies comparing the impact of these two approaches in conserving the rich flora and fauna resources have not been carried out on the study sites. This study is aimed at filling the knowledge gaps and assessed the differences in vegetation status of Okomu National Park and Okomu Forest Reserve. The purpose is to determine how these rich flora resources have been conserved and the conservation strategies that have met this goal, by assessing and comparing biodiversity status. In this study, a systematic sampling technique was used. Four transects (2 km) of 2 m width were utilised. One transect each was laid out per range (Arakhuan, Igwuowan, Babui Creek and Julius Creek range) in Okomu National Park. Four plots of 50 m × 50 m were alternately laid out along each transect. All living trees within each of the sample plots with diameter at breast height (Dbh) ≥ 10 cm were identified. The results indicated that the estimated mean number of trees per hectare for Okomu National Park and Forest Reserve were 386 (74 species) and 160 (55 species) ha^-1, respectively. The following tree species Strombosia pustulata, Nauclea didirechii, Diospyros species and Barteria fistulosa were more prominent in Okomu National Park while in Okomu Forest Reserve, Diospyros spp., Allanblackia flouribunda, Terminali ivorensis, and Antanotha macrophylla were the dominant species. The species richness were 12.76 and 10.84 for Okomu National Park and Forest Reserve, respectively. Shannon-Wiener diversity index (H^I) for Okomu National Park and Forest Reserve were 3.920 and 3.795, respectively. Despite the variation in the per hectare estimates of the two sites, the study revealed that floristic similarity between the two sites was significantly above the critical level judging from the value of the Sorenson’s index (52%). The study proved that Okomu National Park showed better impact in conserving the rich flora resources than Okomu Forest Reserve.

Key words: Flora composition, species richness, species diversity, similarity index, vegetation status.