Status and distribution patterns of selected medicinal and food tree species in Owerri West Local Government Area of Imo State, Nigeria

Abstract

The distribution of medicinal and food tree species in Owerri West Local Government Area (LGA) of Imo State were assessed. Data were collected using socio-economic survey and biological study. A total of 50 respondents from the study area were randomly selected and relevant information on the uses and contributions of tree species of food and medicinal importance was collected through the use of semi-structured questionnaire and Focused Group Discussion (FGD). A total of ten communities were sampled, with one community in each of the ten political wards in the LGA. Tree species of ethno-botany and food relevance were identified and enumerated in the course of field survey in the study communities. The spatial distributions of six most-frequently utilized tree species were mapped using Geographical Information System (GIS). Data were statistically analyzed using descriptive statistics and one-way analysis of variance. A total of 22 tree species, belonging to16 families, known to be used for medicinal and food purposes, were identified in the ten study communities. Dacryodes edulis of the family Burseraceae was the most abundant tree species in the area having about 13% of the species encountered. In the study locations, the least-occurring species were Dialium guineensis and Garcinia kola with 0.27% each. Fabaceae and Rutaceae were the most represented families with 13.64% and 3 species each belonging to each of the two families. The six (6) mostly utilized species in the area were Dacryodes edulis, Chrysophyllum albidium, Persea americana, Psidium guajava, Mangifera indica and Moringa oleifera. The seven tree species that were abundant in the study area were Annona muricata, Citrus sinensis, Cola nitida, Dacryodes edulis, Elaeise quineensis Magifera indica and Psidium guajava with relative density (RD) of 6.29, 11.98, 12.72, 12.99, 6.16, 9.20 and 9.47, respectively. Dennettia tripetala and Persea americana were frequent species with RD values of 4.33 and 4.06, respectively. Dialium guineensis Garcinia kola and Pentaclethra macrophylla were threatened, having RD of 0.27, 0.27 and 0.47, respectively. A total of 8 tree species including: Anacardium occidentale, Azadirachta indica, Chrysophyllum albidium, Citrus aurantiifolia, Citrus lemon, Gliricidia sepium, Irvingia gaboneensis and Moringa oleifera were rare in the area with RD of 1.76, 1.49, 2.44, 2.44, 1.49, 1.69, 1.76 and 2.10, respectively. The threatened species include Dialium guineensis, Garcinia kola and Pentaclethra macrophylla with RD values of 0.27, 0.27 and 0.47, respectively. In seven of the ten communities, (i.e. Emeabiam, Eziobodo, Nekede, Ihiagwa, Okuku, Obinze, and Umuguma), Dacryodes edulis was the dominant species with 23, 35, 32, 32, 9, 10 and 14 stems, respectively while Mangifera indica predominated in Avu, Irete, and Ndegwu with 24, 14, and 11stems, respectively.

Keywords: Species abundance, status, distribution, utilization, extinction