J. Appl. Environ. Biol. Sci., 1(9)276-282, 2011 ISSN: 2090-4215 Journal of Applied © 2011, TextRoad Publication Environmental and Biological Sciences www.textroad.com Checklist of the Tree/Shrub Species of Edo South, Nigeria Jane Ihenyen; Mensah, J.K.; Osunde, W.O. and Ogie-Odia, E.* Department of Botany, Ambrose Alli University, Ekpoma, Edo State, Nigeria. ABSTRACT This study was carried out to assess the stocking status with regards to the Tree/Shrub species of the forest reserves in Edo South typified by Okomu, Sakponba, Ehor and Ozalla-Ora-Iulleha forest reserves. Randomized block design was employed in the survey of these forest reserves. Sample plots of 30 m x 30 m were marked out in three compartments of Ehor, Ozalla-Ora-Iuleha, Sakponba and five compartments in Okomu forest reserves. All trees and shrubs encountered were identified. The forest reserves had one hundred and ninety-nine species including sixty-two timber species distributed into forty-five families with twenty-one of these species common to the four reserves. Fabaceae had the highest species diversity of thirty-nine while sixteen of these families were monospecific. The distribution of the species in the forest reserves were as follows: Okomu, 118; Ehor, 99; Sakponba, 81 and Ozalla-Ora-Iulleha reserves 49. Thirty per cent of the species were shrubs while trees made up the remaining seventy per cent. Okomu had the highest number of shrubs (41 spp.) constituting 35% of the total number of species recorded while the remaining 77 spp. were trees making up 65%. There was no correlation between the sizes of these forest reserves and the number of species encountered in these four reserves under study. KEY WORDS: Forest reserves, diversity randomized block design, monospecific, shrub. INTRODUCTION The forest play a vital role in regulating climate, controlling water runoff, providing shelter and food for wildlife and purifying the air. In addition, they provide valuable materials such as wood, paper pulp etc. [1]. The richest of most diverse terrestrial ecosystem on the earth are the tropical forests. Although they now occupy less than 10% of the earth’s land surface, they contain more than two-thirds of all higher plant biomass and at least one half of all plants, animals and microbial species in the world [2]. In Nigeria, the greatest number of plant species are found in Edo, Ekiti, Ondo, Ogun, Oyo, Osun and Cross River States where the annual rainfall is in excess of 2,000 mm [3]. The forested area of Edo State was 577,373 hectares which is about 30% of the state’s total land area. About 133,234 hectares was ceded through dereservation over the years mainly for agricultural purposes. By 2002 the forested area had reduced to 439,139 hectares or about 23% of the total area of the state [4]. Further studies [5,6] have shown that Ehor forest reserve had been so exploited that the density of trees/shrubs of the available population was less than one stand per hectare of each species. As a consequence of this deforestation, for various purposes, some plants have been lost and others threatened. This paper therefore seeks to highlight the stocking status of the trees and shrub species in southern Edo State. Though the state has three senatorial district, it will be grouped into two: North and South Edo (made up of Edo South and Central) for the purpose of this work. Sakponba, Okomu, Ehor and Ozalla-Ora-Iulleha forest reserves were sampled for Edo South. MATERIALS AND METHODS Study Location Ehor and Ozalla-Ora-Iulleha forest reserves occupy an area of 7,680 hectares (76.8 km2) with 48 compartments of 160 hectares (1.6 km2) each. Ehor forest reserve lies between latitudes 6034N and 6038N and longitudes 5054E and 5058E about 56 km. North of the state capital Benin-City, in Uhunmwode Local Government Area of Edo State. On the other hand, Ozalla-Ora-Iulleha forest reserve is located between latitudes 6030 and 70N and longitudes 5030 and 60E about 65 km. North of Benin City in Owan West Local Government Area of Edo State. Sakponba forest reserve occupies an area of 50250 hectares (502.5 km2) within Orhionmwon Local Government Area of Edo State. It is divided into area BC 29 with 101 compartments and BC 32/4 with 75 compartments. It lies on latitude 6004N and longitude 5032E. On the other hand, Okomu forest reserve occupies an area of 123800 hectares (1238 km2) forty kilometers West of Benin City in Ovia South West Local Government Area of Edo State. It lies between latitudes 50 and 60 10N and longitude 50 and 5030E. It is divided into two areas BC 9 with 158 compartments and BC 10 with 318 compartments. SURVEY METHOD Sample plots of 30 m x 30 m were mapped out in the compartments of study according to the method of Inegbedion 2008. For Ehor forest reserve, compartment 81, 95 and 112 were surveyed while for Ozalla-Ora-Iulleha, Sakponba and *Correspondence Author: Ogie-Odia Efosa. Department of Botany, Ambrose Alli University, P.M.B 14, Ekpoma, Edo State, Nigeriae-mail: [email protected] 276 Ihenyen et al., 2011 Okomu forest reserves, compartments 5,14,20; 46,59,64 of area BC 29 and 65,35 and 104 of area BC 10; 4 and 29 of area BC 9 respectively. While three compartments were sampled for other three forest reserves, five compartments were sampled for Okomu forest reserve because of its large size. All species encountered were identified using appropriate taxonomic literature [7-11]. The species diversity in each family present was also noted. RESULTS AND DISCUSSION 0ne hundred and ninety-nine species and their distribution into the various forest reserves are presented in Table 1. These species are distributed into one hundred and forty-nine genera and forty five families. Sixty-two of these species are well known timber plants. Fabaceae had the highest species diversity of thirty-nine. Other authors [12-17] also reported high Fabaceae species diversity in their various research sites. Rubiaceae came a distant second with fifteen species followed by Euphorbiaceae with eleven species. Other families with relatively high species are Meliaceae (ten), Annonaceae, Apocynaceae, Moraceae and Sterculiaceae with nine species each while Ebenaceae was represented by eight species. On the other hand, fifteen families were monospecific indicating a very poor diversity for the concerned families. Twenty-one species were common to the four forest reserves while three (Monodara myristica, Drypetes sp. and Pterygota sp.) were restricted to Ozalla-Ora-Iulleha, twenty to Sakponba, fifty-eight to Okomu and thirty-two to Ehor forest reserves (Table II). Okomu forest reserve had the highest species diversity of one hundred and eighteen followed by Ehor forest reserve with ninety-eight species. Sakponba forest reserve had eighty-one species while the Ozalla-Ora-Iulleha reserve has the least number of species of forty-nine. This result shows that the species richness of the reserves have on correlation with their sizes. The tree/shrub species of Okomu is 65% of trees and 35% shrubs making it the richest in shrub species. Numerically this translates to seventy-seven tree species and forty-one shrub species. Sakponba had the least shrub species of five (7%) and seventy-six tree species (93%). Although Sakponba forest had the highest percentage tree species, numerically, Ehor forest reserve had the highest number of tree (90) species translating to 91% while the shrub population is eight species which is 9% of the tree/shrub species. Ozalla-Ora-Iulleha forest reserve consist of five shrubs (11%) and forty-four trees (89%) species. On the whole, the four reserves were populated by 30% shrub species and 70% tree species. Table I: SPECIES DISTRIBUTION INTO THE VARIOUS FOREST RESERVES S/N SPECIES FAMILIES HABIT FOREST RESERVES OZALLA –ORA-IULLEHA SAKPONBA OKOMU EHOR 1 Dracaena deisteiliana Engl Agavaceae Shrub √ 2 D.mannii Bak Agavaceae Shrub √ √ 3 Antrocaryon micrazter A chev. Anacardiaceae Tree √ 4 Lannea welwitschii (Hiern) Engl. Anacardiaceae Tree √ 5 Mangifera indica Linn. Anacardiaceae Tree √ 6 Spondias mombin Linn. Anacardiaceae Tree √ 7 Annonidium mannii (Oliv.) Engl. & Diels Annonaceae Tree √ √ √ 8 + Cleistopholis patens (Benth.) Engl. & Diels Annonaceae Tree √ √ 9 Enantia chlorantha Oliv. Annonaceae Tree √ √ √ 10 Monodora myristica (Gaertn.) Dunal Annonaceae Tree √ 11 M.tenuifolia Benth. Annonaceae Tree √ 12 Polyalthia suaveolens Engl. & Diels Annonaceae Tree √ √ 13 Polyceratocarpus parviflorus (Bak.f) Chesq. Annonaceae Tree √ 14 Uvariopsis dioica (Diels) Robyn & Chesq. Annonaceae Tree √ 15 Xylopia aethiopica (Dunal) A.Rich Annonaceae Tree √ √ √ 16 + Alstonia boonei De Wild Apocynaceae Tree √ √ √ √ 17 + Funtumia elastica (Preuss) Stapf. Apocynaceae Tree √ √ √ √ 18 Hunteria umbellata (K.Schum) Hailier Apocynaceae Shrub √ √ 19 Mezoneuran benthamianum Baill. Apocynaceae Tree √ 20 Picralima nitida (Stapf.) Th. & H.Dur. Apocynaceae Tree √ 21 Pleioceras barteri Baill. Apocynaceae Shrub √ 22 Rauwolfia vomitoria Afzel Apocynaceae Shrub √ √ √ √ 23 Tabernaemontana pachysiphen Stapf. Apocynaceae Tree √ √ √ 24 Voacanga africana Stapf. Apocynaceae Tree √ 25 Elaeis guineensis Jacq. Arecaceae * Tree √ √ √ √ 26 Vernonia amydalina Linn. Asteraceae * Shrub √ √ 27 Markhamia tomentosa (Benth) K.Schum ex Engl. Bignoniaceae Shrub √ 28 Newbouldia laevis (P.Beauv.) Seeman ex. Bureau Bignoniaceae Tree √ √ 29 Spathodea companulata P.Beauv. Bignoniaceae Tree √ 30 + Bombax brevicuspe Sprague Bombacaceae Tree √ 31 +B.buonopozense P.Beauv. Bombacaceae Tree √ √ 32 + Ceiba pentandra (L.) Garten Bombacaceae Tree √ √ √ 33 Cordia millenii Bak. Boraginaceae * Tree √ √ 34 Aucoumea klaineana Pierre Burseraceae Tree √ 35 + Canarium schweinfurthi L. Burseraceae Tree √ √ 277 J. Appl. Environ. Biol. Sci., 1(9)276-282, 2011 36 + Dacryodes edulis (G.Don.) H.J. Lam Burseraceae Tree √ √ √ √ 37 Santiria trimera. (Oliv.) Aubrev. Burseraceae Tree √ 38 Euadenia trifoliata Oliv. Capparidaceae Shrub √ 39 Buchholzia coriacea Engl. Capparidaceae Tree √ 40 Carica papaya L. Caricaceae * Tree √ 41 + Allanblackia floribunda Oliv. Clusiaceae Tree √ √ 42 Garcinia kola Heckel Clusiaceae Tree √ √ √ 43 Pentadesma butyracea Sabine Clusiaceae Tree √ 44 Symphonia globulifera Linn.f Clusiaceae Tree √ 45 + Terminalia ivorensis A.chev.