Biodiversity Inventory of Omo Biosphere Reserve
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GEBR PROJECT REPORT BIODIVERSITY INVENTORY OF OMO BIOSPHERE RESERVE SUBMITTED BY NIGERIA NATIONAL MAB COMMITTEE EDITED BY B.A. OLA-ADAMS APRIL 2014 1 TABLE OF CONTENTS PAGE 1.0 Description of the Omo Biosphere Reserve 2 1.1 Location, Geology and Climate 2 1.2 The Biological Resources of the Reserve 2 2.0 Limitation of the Study 11 3.0 Plants Biodiversity Inventory 15 3.1 Methodology for Flora Data Collection 15 3.2 Structure of the Forest 15 3.3 Floristic Characteristics of Omo Biosphere Reserve 16 3.3.1 Species Richness 16 3.3.2 Family Composition 18 3.3.3 Diversity Indices 19 3.3.4 Similarity Indices 19 3.3 .5 Size Class Distribution among Trees and Shrubs 19 4.0 Mammalian Fauna and Avifauna Diversity 28 4.1 Introduction 29 4.2 Methodology 29 4.2.1 Bird Survey 29 4.2.2 Mammalian Survey 29 4.3 Results 29 4.3.1 Hunting Evidences 30 4.4 Limitations and Recommendations 30 5.0 Insect Fauna of Omo Biosphere 47 5.1 Introduction 48 2 5.2 Methodology 48 5.3 Results and Discussion: 48 5.4 References 57 3 FIGURES Figure 1: Map of Nigeria showing location of Omo Biosphere 9 Figure 2: Map of Omo Biosphere Reserve 10 Figure 3: No of Plant Spices 17 Figure 4: No of Spices in families of Tree spices in Omo Biosphere 17 Figure 5: No of Spicies in families of 18 Figure 6: Tree Omo Biosphere size plants (cm) Distribution 20 Figure 7: Diversity indices 21 TABLES Table 1: Summary of Species Richness in Omo Biosphere Reserve Table 2: Flora Characteristics Table 3: Similarity Indices Table 4: Current Bird List and Their Status in Omo Biosphere Reserve Table 5: Current Mammal List and Their Status in Omo Forest Reserve Table 6: Matrix of Observational Means for Mammal Species in Omo Forest Reserve Table 7: Insect Species from light trap in Omo Biosphere Table 8: Checklist of Miicroarthropods in the Study Area PLATES PLATES A Make-Shift Bridges 12 PLATES B Make-Shift Bridges 13 4 PLATES C Slippery Road 14 PLATES D Slippery Road 14 PLATES E Use of motorcycle 14 PLATES F An empty gun catridge 31 PLATES G An illegal hunter with a murdered Mona monkey (Cercopithecus mona) 31 PLATES H Illegal hunters camp at sojukorodo axis of J1 31 PLATES I Dwarf mongoose (Herpestes pulverulenta) been trapped with wire mesh at J4 31 PLATES J Fresh antelope dung 32 PLATES K Forest elephant (Loxodonta Africana cyclotis) play ground observed in J1 33 PLATES L Observing elephant dung in J1 33 PLATES M Timber lorry hauling out illegal forest wood in J3 34 PLATES N Field officer Clifford penning sample record 34 PLATES O Clifford and hunter Francis from J4 identifying animals using West Africa Large Mammal guard 35 PLATES P Termite Mound in Etemi SNR 49 PLATES Q Termite Mound in Etemi SNR 49 PLATES R Termite Mound in Etemi SNR 50 PLATES S Termite Mound in Etemi SNR 50 PLATES T Mounds of macro Termite Molding in Etemi SNR 50 PLATES U Log Attacked by Ambrosia bettle 51 PLATES V Gruds extracted from wood at Temitami 51 PLATES W Gruds extracted from wood at Erin Camp 51 PLATES X Woody Aphids on Sterculia spp 51 PLATES Y Woody Aphids on a plant 51 5 PLATES Z Eriophid gall mite attack 52 PLATES Za Attack by leaf minners 52 PLATES Zb Woody Rhids on streculia spp PLATES Zc Woody Rhids on streculia spp PLATES Zd Epidphid call mite attack PLATES Ze Attack by Leave Mines APPENDIX Appendix 1: Plants species in Omo Biosphere Reserve Appendix 2: Distribution of Families in Omo Biosphere Reserve 6 INTRODUCTION 1.0 DESCRIPTION OF THE OMO BIOSPHERE RESERVE 1.1 LOCATION, GEOLOGY AND CLIMATE Omo Biosphere Reserve, which derives its name from River Omo that traverses it, is located north of Sunmoge, between latitudes 6o 35’ to 7o 05’ N and 4o 19’ to 4o 40’ E in the Ijebu area of Ogun State in southwestern Nigeria. The Reserve was constituted in 1925 as part of a bigger Shasha Forest Reserve. Shasha was later split into Omo, Oluwa and Shasha Forest Reserves, the last two lying to the east and north- east of the present Omo. To the north and north-west of the Reserve are Ife and Ago-Owu, and Oshun Forest Reserves, respectively. Omo covers about 130 500 hectares, which includes a 460 ha Strict Nature Reserve (Okali and Ola-Adams 1987), plus about 6 500 ha of enclaves and cut out areas with a total of about 20,000 inhabitants (Dike 1992); is roughly triangular in shape, and tapers southwards with its southernmost tip about 20 km from the Atlantic coast. River Oni forms its eastern boundary while the western boundary at the southern tip is, for about the first 50 km, formed by River Omo (formerly River Shasha) before the Reserve broadens out such that River Omo is centrally located for the rest of the length of the Reserve (Fig. 1). Geologically the Reserve lies on crystalline rocks of the undifferentiated basement complex which in the southern parts is overlain by Eocene deposits of sand, clay and gravel. The terrain is undulating and the maximum elevation of 150 m above sea level is towards the west while the lowest parts of the Reserve are in the south where the River Omo joins River Oni before flowing into the Lekki Peninsular on the Atlantic coast. The Lagos-Ore-Benin Highway passes through the southern tip of the Reserve. The mean annual rainfall ranges from about 1600 to 2000 mm with two annual peaks in June and September, with November and February being the driest months. 1.2 THE BIOLOGICAL RESOURCES OF THE RESERVE The Reserve is in the mixed moist, semi-evergreen rainforest zone, in the Congolian sub-unit of the Guinea- Congolian Centre of Endemism or Phytochorion (White 1983, Mackinnon and Mackinnon 1986). The Guinea-Congolian zone is extremely rich in species and has very high levels of endemism. The area is the richest in Africa for butterflies, a high proportion of which species are endemic, highest in richness of bird species and richest in mammal diversity (Mackinnon and Mackinnon 1986). Sanford (1969) observed 24 orchid species 12 of which are characteristic of wet forest sites while 3 are exclusive to Omo in his study of orchid species in 31 sites in Nigeria. 7 The northern part of Omo Biosphere Reserve is, considering the north-south length, relatively dry forest. Hall (1977) has concluded that much of the variation in forest species composition was associated with soil differences and that a primary division of the Nigerian high forest should be made according to the underlying soil type-Ferrallitic or Ferruginous Tropical Soil. Forests on Ferruginous Tropical soil could, according to him, be usefully divided based on rainfall, but allowance for other factors was needed. Forests on Ferrallitic soil, on the other hand could be divided on a geographical basis which mainly reflect factors other than rainfall. Hall’s ordination of Nigerian high forests based on pre-exploitation species composition put Omo sample plots in the wet sub-group of the ferruginous tropical soil group. Five hundred and four plant species were encountered during the biodiversity inventory (BRAAF 1999). Of the 504 species, 245 species were trees, 71 shrubs, 118 herbs, 50 climbers and 20 climbing shrubs and Iianas. 29 species of orchids, 28 species of Pteridophytes, 27 species of Bryophytes, 17 species of fungi (mushroom) and 3 species of lichens were inventoried during the biodiversity survey. Forty-four trees and shrubs are restricted to the core zone and eleven trees and shrubs are restricted to the buffer zone of the biosphere reserve. Out of the 279 species of ground flora recorded at all sampling sites, 84 and 25 species are restricted to the core and buffer zones respectively. The families with abundant individuals within the reserve include Compositae, Poaceae, Violaceae, Rubiaceae, Lilliaceae Araceae, Ebeneceae and Papilionoideae. The most common tree species include Diospyros spp., Strombosia pustulata, Rinorea dentata Voacanga africana and Drypetes spp. The estimated basal area and standing wood volume at Omo Forest Reserve were 28.97 m2 and 16.8 m2 per hectare, respectively. The estimated mean annual increment in the reserve is 5.113 ± 0.4551 m3/ha/yr. Timber exploitation, establishment of monoculture stands of tree crops, clearance for cultivation and gap formation, created by wind throw (36.7%), snapping (35.3%), branch fall (21.4%) and standing dead trees (6.6%), within the reserve have seriously altered the forest structure, species composition and the habitat. No less than 35,775 logs of sixty five tree species are removed annually from Omo Forest Reserve (NFEWSG, 1994). Some of the trees harvested include Khaya ivorensis, Cordia millenii, Sterculia sp., Nauclea diderrichii, Mansonia altissima, Terminalia sp., Celtis sp., Brachystegia sp., Alstonia congensis and Milicia excelsa. As at 1995, over 26,000 hectares had been cleared and planted up with mainly Gmelina arborea (22,562 ha), Pines (31.5 ha) and indigenous species (1310.5 ha). Plantations of cola and cacao species are also 8 established around the enclaves. Small patches of forest are also cleared annually for the cultivation of cash crops and arables. Results of enrichment line plantings have shown that only certain light demanding species are capable of satisfactory growth as line plants. Such plants include Triplochiton scleroxylon, Terminalia ivorensis and perhaps Tectona grandis. Although, Khaya ivorensis has shown a consistent growth, the Meliaceae (except Cedrela) are unsuitable for line planting owing to their slow growth and susceptibility to shoot-borer attack.