DIVERSITY AND ABUNDANCE OF LESSER-KNOWN PLANT SPECIES OF FOOD AND ETHNOMEDICINAL POTENTIAL IN TROPICAL RAINFOREST ECOSYSTEM OF SOUTHWEST NIGERIA

The rate of forest loss today is alarming. The subsequent implications of this include the loss of plant species with potentials that are valuable to national development and rural livelihood. This study therefore assessed the diversity and the relative abundance of lesser known plant species with food and ethnomedicinal values in tropical rainforest ecosystem of Southwest Nigeria. Data were collected from eight plots of equal size (50×50 m) located in four forest reserves distributed in three states of Nigeria. Systematic cluster sampling technique was adopted for sample plot location. The reserves used are Ala and Oluwa forest reserves in Ondo State, Omo forest reserve in Ogun State and Shasha forest reserve in Osun State. Identification of all three species with a diameter at breast height (dbh) >10 cm were carried out in each plot. Frequency of all species identified was computed and the species were also classified into families. Relative density was obtained with the total number of species and number of families encountered per hectare. Shannon-Wiener biodiversity index (H’) was used for biodiversity assessment and Evenness index (E) for species distribution. Habitat occupancy was also used to study the distribution of all species across the different communities. Percentage of plant species with potentials for food and medicinal values was calculated. It was discovered that most of the plant species (60%) had food and medicinal values. The relative density and frequency of these species shows that most of them are rare while others are threatened with extinction. Since the role of these plant species cannot be dispensed with, appropriate management strategies that will make them sustainable are recommended.