Tree Species Diversity of Ikogosi Warm Spring and Arinta Waterfall Watersheds, Nigeria: Implication for Sustainable Ecotourism

Abstract

An in-depth knowledge of the richness, diversity and species composition of plant community is vital for providing information for planning and sustainable utilization. This study assesses the diversity of tree species of Ikogosi warm spring and Arinta waterfall watersheds in Ekiti State, Nigeria. Direct observation and vegetation assessment were used for data collection in two hectares (ha) of land divided into four plots of 50 m by 50 m in each of the two study sites (Ikogosi warm spring and Arinta waterfall). Two plots were diagonally selected within each hectare. All living trees of basal diameter ≥10 cm were identified and classified into families. Shannon-Weiner diversity index, species evenness, relative density (RD), relative dominance (RD₀) and importance value index (IVI) were used to assess and compare tree species diversity and abundance. Sorenson’s coefficient was used to compare sites for overlapping of similarity. The results revealed that seventy eight (78) species and 25 families were recorded in both watersheds with family Malvaceae having the highest species density (15). Malacantha alnifolia (5) and Voacanga africana (5) were the species most frequently encountered. Species diversity indices revealed vegetation with very high tree species diversity and abundance in the two study sites. Species evenness value revealed even distribution in Arinta waterfall than in Ikogosi warm spring. Diameter and height distribution of trees at the two watersheds indicates a forest structure that is immature and still expanding. Anthocleista vogelii, has the highest value of RD₀ (15.63) and IVI (10.6) respectively. The study revealed that some species such as Anthonotha macrophylla, Aningeria robusta, Bridelia atroviridis, among others are threatened and endangered. Consequently, it was recommended that management strategies should be put in place to improve status of the watersheds while conservation efforts should be stepped up for species with rarity index value to prevent them from going into extinction.