Journal of Forestry Research and Management. Vol. 16(3).12-26; 2019, ISSN 0189-8418 www.jfrm.org.ng Assessment of Threatened Medicinal Plants in Selected Locations in South-Western Nigeria *1Lawal I. O., 1Rafiu B. O 2Falana A.R,. and 1Adam, A. A. 1Biomedicinal Research Centre, Forestry Research Institute of Nigeria, P.M.B. 5054, Ibadan. 2Federal College of Forestry, Ibadan, Nigeria. *Corresponding author: [email protected]; Tel: +2348035059095 ABSTRACT Plant as a biotic factor plays a significant role in the well-being of man. The relationship between man and plants has been very cordial since time immemorial. The burgeoning world population and the concomitant increase in anthropogenic activities led to the rapid erosion of natural ecosystems. This study was designed to assess the categories and the ethno-medicinal information of endangered medicinal plant species in Igbo-Nla, Odeda Local Government Area of Ogun state and International Institute of Tropical Agriculture (IITA), Akinyele Local Government Area of Oyo state, Nigeria for proper referencing. The land area of 5 acres were marked out from the locations and divided into 4 compartments of 1.25 acres. The plant species found were identified, enumerated and recorded accordingly. Ethno-botanical information such as the local names, parts used and ailments which they can be used to treat were captured. Frequency of occurrence, species abundance/richness and others were used to analyze the information obtained. It was revealed that 33 species belonging to 12 angiosperm families were recorded in IITA while 40 species belonging to 25 plant families were recorded in Igbo-Nla with species in Fabaceae family having the highest frequency of occurrence at both study areas. Among other species identified, Tamarindus indica and Khaya ivorensis were the most encountered species (5.88%). The leaves and stem bark are the most frequently used parts of these plant species for the treatment and management of ailments ranging from leprosy, ulcer, fever, cough, fungal infection, sore-eyes, and nervous disorder, among others. Plant diversity is the bedrock of life sustainability, which plays a significant role in nation’s economy. Hence, a vision towards strategic conservation and sustainable use of medicinal plants is therefore necessary for sustainable development. Endangered indigenous tree species identified in this study play significant roles in the lives of the local people as they rely mostly on the forest for traditional medicines and as such for means of livelihood. Therefore, urgent, concerted efforts must be made to conserve these natural plants’ habitats by curtailing activities such as incessant deforestation and harvesting of plants materials as well as habitat conversion which altogether pose tremendous threat to continuous existence and availability of the plant species. Keywords: Plant diversity, Endangered species, Fabaceae, Ethno-medicinal uses, Conservation. Introduction globally, especially by rural populations in Man and plants have been in close developing tropical regions (Akinyemi, relationship throughout the development of 2000). Anokbongoo (1992) reported that all civilizations. The use of plants in there is always a correlation between village traditional medicine is gaining more priority uses of a plant and its activity in biological worldwide (Farnsworth 1988) therefore screening system. Zahoor et al. (2012) making medicinal plants to be of immense elucidated that the burgeoning world economic importance and widely consumed population and the concomitant increase in 12 Journal of Forestry Research and Management. Vol. 16(3).12-26; 2019, ISSN 0189-8418 www.jfrm.org.ng anthropogenic activities are rapidly eroding been on the range of extinction, therefore, natural ecosystems, resulting in loss of the studies of characterization of the ethno- natural habitat for a great number of geographical, ecological and trends of medicinal herbs and trees, which play threatened species require an urgent important roles in the primary health care of attention. Thus, this study is designed to rural populations globally. However, Kirby assess, categorize and study the ethno- (1996) reported that most plants used in geographical information of endangered traditional medicine are still understudied species in Odeda Local Government Area of and in developing countries, notably in Ogun state and Akinyele Local Government West Africa, new drugs are not often Area of Oyo state, Nigeria for proper affordable. Thus, up to 80% of the referencing. population uses medicinal plants as Materials and Methods remedies (Hostellmann and Marston, 2002). Numerous medicines have been derived Study areas from the knowledge of people from tropical The study was carried out at two different forests and clearly there will be more in the locations; Tree Heritage Park at the future. This reason is enough for any and all International Institute of Tropical programs to be concerned with the Agriculture (IITA) in Akinyele Local conservation, development and protection of Government Area of Oyo state and Igbo-Nla tropical forest regions. in Orile Ilugun, Odeda Local Government Khan (2002) elucidated that poverty, Area of Ogun state, Nigeria. ignorance and unavailability of modern IITA is located on the Latitude 70 23'47''N health facilities, had forced most people, and Longitude 3055'0''E (Figure 1). It has a especially rural people, to practice sub-humid climate which is characterized traditional medicines for their common day by rain forest and slightly heavy rainfall. Its ailments and engaged in the trade of rainfall is bimodal with mean annual rainfall medicinal plants. Medicinal plants are also of 1250mm. It has wet season from March - produced in compound farms or home October and dry season from November - gardens alongside fruits and vegetables in February having annual maximum the eastern part of Nigeria. Plants such as temperature ranging between 27-34 oC and Milicia excelsa, Bombax spp., Newbouldia annual minimum temperature ranging from laevis, kola accuminata, Garcinia kola, and 20-23 oC (Oguntunde, 1998). Igbo-Nla in Chrysophyllum albidum have been reported Orile - Ilugun is situated in Odeda Local to be widely preserved in rural villages of Government Area of Ogun State at an Edo State, Nigeria for their medicinal and elevation of 157 meters above sea level and cultural values (Azeez et al., 2010). Tuley its population amounts to 118,097, with (1997) reported that deforestation has led to Latitude 709'0" N and Longitude 3024'0" E the extinction of many medicinal plants and as depicted in figure 1. It is characterized by other genetic materials before they are ever tropical climate with distinct wet season. documented. Habitat conversion threatens The area is located in a region characterized not only the loss of plant resources, but also with a bimodal rainfall pattern, commencing traditional community life, cultural diversity in March, plentiful in July and September, and the accompanying knowledge of the with a short dry spell in August, the long medicinal value of several endemic species dry season extends from November to (Okigbo et al., 2008). The rate of March. Annual rainfall ranges between deforestation in Nigeria is alarming, most 1400 and 1500 mm. The region is valuable species of medicinal plants have characterized by relative high temperature 13 Journal of Forestry Research and Management. Vol. 16(3).12-26; 2019, ISSN 0189-8418 www.jfrm.org.ng with a mean annual air temperature being about 30oC (Ako, 1979). Figure 1: Map showing the location of the study areas Data collection PLANTLIST” (2013). All the endangered The land area of five acres was marked out tree species encountered in the study areas from the two locations and was divided into were assigned to families and the number of four compartments of 1.25 acres. The tree species in each family was recorded. species found in each compartment were Methods of data analysis identified by the gardener in charge of the Data collected from the study areas were park in IITA, while farmers and the people presented using descriptive statistical tools living around Igbo-Nla revealed the names such as table to show the trend of of the species identified. The endangered endangered medicinal species in the study medicinal species were enumerated and areas. Frequency of occurrences as well as recorded; % Frequency of the species was calculated Plant identification accordingly. The following biodiversity The plant species were first identified using indices were employed following Magurran local ‘Yoruba’ names and later matched (2004); with their respective scientific Frequency percentage (%) classifications through consultation of FP (%) =F/N * 100………………... (1) relevant literature (Gbile, 1984; Keay, 1989; Where; Burkill, 1995) while the current taxonomic F = number of a particular species classification was validated on “THE 14 Journal of Forestry Research and Management. Vol. 16(3).12-26; 2019, ISSN 0189-8418 www.jfrm.org.ng N = total number of plant species H' is the Shannon-Wiener diversity index; encountered S is the total number of species in the (i) Shannon-Wiener diversity index: community; In is natural logarithm H'=- Spi ln( pi ) Results and Discussion Where; i=1 The endangered species within the study H' is the Shannon-Wiener diversity index; areas as well as their frequency of S is the total number of species in the occurrences were presented in Tables 1 and community; 2 below. It was revealed that 33 species pi is the proportion of S made up of the ith belonging to 12 angiosperm families were species; recorded in IITA. The families include, ln is natural logarithm. Apocynaceae, Anacardiaceae, Capparaceae, Combretaceae, Fabaceae among others (ii) Simpson’s Diversity index: (Table 1). The highest number of species Where D is Simpson’s diversity, (13) was recorded in Fabaceae, while other ni is the abundance of the ith species and species had frequency of one (1). N is the abundance of the total stand Tamarindus indica has the highest percentage frequency (5.88%) while other (iii) Shannon-Wiener’sspecies evenness species had the same percentage frequency index: EH = H'/Hmax=H'/ln(S) of 2.94%.