Eric Et Al., 2019 ABSTRACT INTRODUCTION MATERIALS AND
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Nigerian Journal of Agriculture, Food and Environment. 15(2): 15-22 Published September, 2019 Eric et al., 2019 POPULATION ECOLOGY OF PLANTS CONSERVED IN HOMEGARDEN OF ORUK ANAM LOCAL GOVERNMENT AREA, AKWA IBOM STATE, NIGERIA *Eric, E. E., **Udofia S. I. and *Ejizu, A. N. *Forestry Research Institute of Nigeria, Jericho Hill, Ibadan, Oyo State. Nigeria. **Department of Forestry and Natural Environmental Management, University of Uyo, Akwa Ibom State, Nigeria. Correspondence Author: [email protected] 07067717999 ABSTRACT The study was conducted to assess the population ecology of plant species conserved in homegardens of Oruk Anam Local Government Area (LGA) of Akwa Ibom State, Nigeria. The study specifically identified plants species components, plants species diversity and richness in homegardens of the study area. The study area was stratified into 9 sample units based on existing 9 clans, from where 30% of villages were randomly selected from each of the clans making a total of 50 villages. 10 homegarden/households were further randomly selected from each of the sample villages. Data were collected using direct observations and physical field enumeration. Menhinick index and Simpson index models were used to compute richness and diversity indices respectively. Results showed that 87different plant species were inventorized with densities of each plant ranging from 2 to 27 individuals ha-1 and were classified into 6 life-forms (herbs, climbers, shrubs, trees palms, and bamboos) representing 50 different plant families. Plant species richness and diversity indices of homegardens in the study area were significantly high. All the plant species were found to be of socio-economic, medicinal and environmental value to the homegarden owners. Key words: Population, ecology, plant diversity and richness, homegarden INTRODUCTION Homegarden with trees are one of agroforestry practices known to be ecologically sustainable and diversifies livelihood of local community because of the obvious abundance of different plants components of diverse families and life-forms. One of the solutions to meet diverse people’s requirement with fixed land is through the application of agroforestry which is more advantageous than monocropping (Mcneely and Schroth, 2006). Homegarden agroforestry is also believed to be more diverse and provide multiple services for household than other monocropping system and this is due to the combination of crops, trees and livestock (Linger, 2014). Homegarden is an agroforestry practice that is globally known to have dense plant species population combined with livestock which promotes enormous capacity to yield multiples of products to improve farmers’ social, economic and environmental conditions (Udofia, 2007). Adams (1986) and Udofia (2007) stated that homegarden has been a major subsistence strategy for man since creation, and their forms and functions are intimately related to the evolution of society, culture and agriculture. Researches on the ecological conditions of homegardens are important in order to understand the dynamics and potentials of the practice in both ecological and socio-economic dimensions. There is therefore, the need to identify the plants species components of homegardens in the study area and to determine the degrees of plants species diversity and richness of plant community in homegardens of the study area and also the need to document ecology of plant in the study area for adequate conservation, management and sustainability of the existing plant population. MATERIALS AND METHODS Study Area Oruk Anam is one of the Local Government Areas in Akwa Ibom State (Fig, 1), and lies between latitudes 4o49′ and 4o82′ N and longitudes 7o39′ and 7o65′ E (Akwa Ibom State (AKS), 1989). It is located on the southwestern part of Akwa Ibom State and is divided into nine clans, namely Inen, Obioakpa, Ibesit Nung Ikot, Nung Ikot, Nung Ita, Ndot, Ibesit, Abak Midim and Ekparikwa, with a population of 171,839 (NPC, 2006). The study area has three distinguishable vegetation types namely; the saline water swamp forest, NJAFE VOL. 15 No. 3, 2019 15 NIGERIAN JOURNAL OF AGRICULTURE FOOD AND ENVIRONMENT (NJAFE) , Vol 15 (3) , September, 2019 https://www.eruditescholars.net Nigerian Journal of Agriculture, Food and Environment. 15(2): 15-22 Published September, 2019 Eric et al., 2019 fresh water swamp forest and the rainforest belt. It has a mean rainfall of about 2,200 mm to 3,500 mm with sunshine ranging from 1,400 to 1,500 hours per year. Average temperature ranges from 23oC to 31oC in most parts of the year (AKS, 1989). The soils are well drained, deeply weathered and formed sandy, course-loamy materials, have Udic moisture regime, iso-hypertermic temperature regime and broadly classified as Utisol (Obi and Udoh, 2012). Common crops in the area include Telferia (fluted pumpkin) okro, pepper, maize, cassava, yam, coco-yam, melon, Gnetum, bitter leaves and waterleaves. Tree crops commonly found are Oil palm, Mango, Guava, Citrus spp, Pineapple, Avocado pear, African pear, African star apple, Breadfruit, Plantain, Banana and Coconut (AKS, 1989). Fig. 1: Map of Oruk Anam Local Government Area showing the study Area. Source: Geography Department, University of Uyo (2017) Sampling techniques and data collection: Physical field enumeration was carried out after a reconnaissance survey in Oruk Anam Local Government Area, Akwa Ibom State, Nigeria. The study area NJAFE VOL. 15 No. 3, 2019 16 NIGERIAN JOURNAL OF AGRICULTURE FOOD AND ENVIRONMENT (NJAFE) , Vol 15 (3) , September, 2019 https://www.eruditescholars.net Nigerian Journal of Agriculture, Food and Environment. 15(2): 15-22 Published September, 2019 Eric et al., 2019 was stratified into 9 sample units based on the existing clans. Thirty percent of the villages in each of the nine (9) clans were randomly selected, while 10 homegardens were further randomly selected from each of the sample villages for enumeration. Plot-based method of sampling using quadrats of 10m x 10m was adopted for plant enumeration. Plant species found in the quadrats were then identified and counted, and these were used to compute species richness and species diversity. Table 1: Selection of sample villages and households/homegardens in Oruk Anam LGA, Akwa Ibom State, Nigeria for enumeration Clan Total number of No of villages randomly No of households/homegardens villages selected (30%) selected for enumeration Abak Midim 35 11 110 Ekpara- akwa 14 4 40 Ibesit 19 6 60 Inen 19 6 60 Nung Ita 9 3 30 Ndots 30 9 90 Ibesit Nung Ikot 21 6 60 Nung Ikot 5 2 20 Obio Akpa 11 3 30 Total 163 50 500 Source: Field data 2017 Method of data Analysis The enumerated homegardens plant species in Oruk Anam Local Government Area were analyzed for diversity index and richness index using the following formulae stated below. (a) Species richness was analyzed using the formula below; R = S Equation 1 N Where; R = Menhinick’s (1964) plant species index S = Number of species. N = Total number of individuals in the plot. (b) Diversity: species diversity was calculated using the Simpson’s index of Diversity (1949) as follows: Where Equation 2 D = Simpson’s index of Diversity, N = Total number of individuals encountered n1 = Number of individuals of ith species encountered. RESULTS Plant Species Components in Homegardens of Oruk Anam LGA, Akwa Ibom State, Nigeria Details of number plant species, families and life-forms enumerated in homegardens of Oruk Anam LGA, Akwa Ibom State, Nigeria are presented in Table 2. Table 3 shows the level of frequency of species enumerated at the sample clans. Eighty-seven different plant species were enumerated. Densities of the plants ranged generally from two to twenty-seven individuals ha-1. The plants were classified into six life-forms (herbs, climbers, shrubs, palms, bamboos and trees) and 50 families (Table 3). Rustaceae family had the highest number of plant species. In terms of life-forms, trees had the highest frequency of 33 (37.93%) plants species, herbs 25 (28.74%), shrubs 14 (16.09%), climbers 11 (12.64%), palms 3 (3.45%) and the least bamboo 1 (1.15%). All palm species enumerated were found to have equal densities (5ha-1) in the homegardens in Oruk Anam LGA. All the 87 (100%) species were observed in Abak Midim clan, followed by Ndot, 84 (96.99%), species and Ekpara Akwa, 81 (93.10%). NJAFE VOL. 15 No. 3, 2019 17 NIGERIAN JOURNAL OF AGRICULTURE FOOD AND ENVIRONMENT (NJAFE) , Vol 15 (3) , September, 2019 https://www.eruditescholars.net Nigerian Journal of Agriculture, Food and Environment. 15(2): 15-22 Published September, 2019 Eric et al., 2019 Table 2: Plant species found in homegardens of Oruk Anam LGA, Akwa Ibom State, Nigeria. Scientific Name (Herbs) Family Common Name Ethnic Name Density (ha-I) Abelmoschus esculentus (L) Malvaceae Okro Moench Etikke 12 Aframomum meleguata K. Zingiberacceae Alligator pepper Ntuen ibok 6 Schumz Aloe-vera vulgaris (Lam) Amaranthaceae Aloe-vera - 5 Amarantus caudate L. Portulacaceae African spinach Iyang afia 7 Ananas comosus (L) Merrill Bromeliaceae Pineapple Eyop mbakara 6 Arachisz hypogeal L. Papillionaceae Ground nut Mmansan 4 Bryophyllum pinnatum Crassulaceae Air plant 7 Capsicuzm frutescens L. Solanaceae African pepper Ntok ntuen 6 Colocasiza esculenta (L.) schott Aracaceae Cocoyam Ata ikpong 10 Colosynthis vulzgaris Cucrubitaceae Melon Ikon 9 Costus afzar ker-Gawl Costaceae Bush cane Mbritem 6 Curucmin Tumeric Turmeric Adan unen 5 Cymbogon citrate (DC) stapf. Gramineae Lemon grass (Poaceae) Ebana 9 Ipomea batatas (L) Lam. Convolvulaceae