Bight of Benin, Niger Delta, and São Tomé, Part 1: Rainforest Ecoregions
São Tomé, Príncipe, and Annobon forests ecoregion
On mountainous islands 180 miles offshore in the Gulf of Guinea are rainforests with little seasonal climate variation and high humidity all year. The rainforests show a high level of endemism, with 37 endemic plant species on Principe and 95 on Sao Tome. The fern flora and the families Rubiaceae, Orchidaceae, and Euphorbiaceae have many endemics. There are 28 endemic bird species on Príncipe and São Tomé. The island adaptation of gigantism occurs in birds and plants, with the São Tomé olive pigeon, São Tomé giant sunbird, and giant begonias being larger than similar species on the African continent. One dwarf bird, the olive ibis, is found in the ecoregion.
Tinhosas Islands, Autonomous Region of Principe, São Tomé e Príncipe (St. Thomas and Prince), consists of two islands with the largest seabird colonies in the Gulf of Guinea. These are the 3-ha Tinhosa Pequena (N1o23’ E7o17’) and the 20-ha Tinhosa Grande (N1o21’ E7o17’). Birds include the brown gannet, sooty tern, brown and black noddy, and yellow-billed tropicbird. The islands are an Important Bird Area.
Obô Natural Park of Príncipe Island, Autonomous Region of Príncipe, São Tomé e Príncipe (N1o35’ E7o23’) is 14,200 ha. The park includes 24 species endemic to the island. The southern third of the island is an Important Bird area. The biosphere reserve includes Portinho on Principe Island, Bone de Joquei Island (N1o30.5’ E7o25.5’), Tinhosas Islands Ramsar Site, Bom Bom Island (N1o42’ E7o25’), Mosteiros Island (N1o41’ E7o28’), and Pedra da Gale Island (N1o43.5’ E7o23’) (Abreu, 2013). The southern third of Principe is mountainous and an Important Bird Area for seven endemic birds. There are also endemic skinks, burrowing snake, frog, and a shrew subspecies.
Obô Natural Park of São Tomé, São Tomé e Príncipe (N0o12’ E6o33’) is 44,830 ha. The Sao Tome lowland forests (N0o8’ E6o32’) Important Bird Area is 13,000 ha of primary evergreen forests, with 4 endemic birds, 2 endemic bats, and 1 endemic snake. The Sao Tome montane and cloud forests Important Bird Area is 6,000 ha and includes three peaks and a crater lake. There are 6 endemic trees. The Sao Tome northern savannas (N0o25’ E6o38’) is 1,000 ha and includes restricted range bird species and an endemic kite species.
Niger Delta Swamp Forests ecoregion
Africa’s largest coastal wetland, the Niger Delta ecoregion is a generally triangular region in the lower Niger Delta with the Benin River on the western boundary and the Imo River on the eastern boundary. Portions of the Bayelsa, Delta, Imo, and Rivers states extend into this ecoregion. Between the ecoregion and the Atlantic Ocean is a band of mangroves, which is a separate ecoregion. This is a rainforest with a rainy season from March to October. There is some rain in the dry season. The ecoregion is flooded from August to December. In the flooded forest common tree genera include Lophira (Ochnaceae), Pycnanthus (Myristicaceae), Ricinodendron (Euphorbiaceae), Sacoglottis (Humiriaceae), and Uapaca (Phyllanthaceae). Areas that are not flooded have waterlogged soils, with forests dominated by Euphorbiaceae, Annonaceae, Clusiaceae, and Rubiaceae. Endemic mammals include the red colobus and the pygmy hippopotamus. The white-throated guenon and Sclater’s guenon monkeys are considered near-endemic. The elephant, chimpanzee, and crested genet are also present.
Oguta Lake, Imo State, Nigeria (N5o42’ E6o47’) is 572 ha including a natural freshwater lake. Sclater’s guenon is found in nearby forests.
Upper Orashi Forest Reserve, Rivers State, Nigeria (N4o53’ E6o3’) is 25, 165 ha of lowland rainforest and freshwater swamp forest, inundated September to November. The Sclater’s guenon, white-throated guenon, and grey parrot are found in the area.
Biseni forests, Rivers State, Nigeria (N5o15’ E6o30’) includes seasonally flooded Niger Delta forests with Raphia (Arecaceae; palm family), Symphonia globulifera (Clusiaceae), and Ficus (Moraceae). It is an Important Bird Area.
Taylor Creek Forest Reserve, Bayelsa State, Nigeria (N5o10’ E6o30’) is 21,891 ha consisting of freshwater swamp forests, ferns, epiphytes, and aquatic plants. Noted fauna include manatee, dwarf crocodile, and hinge-backed tortoises (Akani et al., 2014b). Seasonally flooded swamp forests are characterized by Raphia hookeri (Arecaceae), Mitragyna ciliata (Rubiaceae), and Nauclea diderrichii (Rubiaceae).
Nigerian Lowland forests ecoregion
This ecoregion extends from the Niger River west to southeastern Benin. Nigerian states that extend into the ecoregion include Delta, Edo, Ekiti, Ogun, Ondo, Osun, and Oyo. The rainforest is bounded by the drier Guinean forest-savanna to the north and west. A three-month dry season extends from December to February. Dominant species are in the Fabaceae and Meliaceae families. The drier northern areas include trees from the Sterculiaceae, Moraceae, and Ulmaceae. Levels of endemism are low in plants; however, Ibadan malimbe, Benin genet, crag gecko, and Petter’s toad are endemic animals. The African elephant and chimpanzee are also present.
World Heritage Site:
Osun-Osogbo Sacred Grove, Osun State (N7o45’ E4o33’), is 75 ha just south of Osogbo. This is a remnant primary forest and the abode of the goddess of fertility, Osun, a Yoruba god. The landscape is dotted with 40 sanctuaries and shrines, sculptures, and art works. It is the last remaining example of sacred groves that used to be in all Yoruba settlements.
Omo Strict Nature Reserve, Ogun State, Nigeria (N6o51’ E4o30’) is a 132,000 ha of evergreen rainforest, with notable species grey-throated rail and African dwarf kingfisher. It is named after the endemic Omo tree (Cordia platythyrsa, Boraginaceae). Other common trees are Diospyros (Ebenaceae), Dracaena (Asparagaceae), and Khaya (Meliaceae). Chimpanzee, pangolin, white-throated guenon, long-created eagle, civit cat, and yellow-casqued hornbill are also present. The reserve is an Important Bird Area. Parts of the reserve are being deforested by cocoa farmers who are squatting in the forest reserve. The Lagos-Ore-Benin Highway also bisects the forest, causing additional access and stress to the forest elephant population. (Sunday, 2019).
Erin-Ijesha (Olumirin) waterfall (N7o34’ E4o54’) is on the southeastern edge of Osun State at the border with Ekiti State.
Gilli-Gilli Game Reserve, Edo State, Nigeria (N6o0’ E5o26’) is 36,300 ha, 30 km southwest of Benin City, south of Okomu National Park. Elephant, 3 species of antelope, white-throated monkey, red-capped mangabay, Mona monkey, and greater spot-nosed monkey are present (Ayanlade 2016).
Ikogosi Warm Springs, Ekiti State (N7o35’ E4o59’) is a resort area.
International Institute for Tropical Agriculture, Oyo State, Nigeria (N7o30’ E3o53’) is 150 ha on the Ona River in Ibadan. The forest is undisturbed since 1965 and has lowland rainforest species. The forest is an Important Bird Area.
Okomu National Park and Forest Reserve, Edo State, Nigeria (N6o20’ E5o15’), is a 12,400-ha Important Bird Area containing the largest block left of lowland rainforest. It is home to the rare white-throated monkey. Rainforest trees include Ceiba pentandra (Malvaceae), Celtis zenkeri (Cannabaceae), Triplochiton scloroxylon (Malvaceae). Birds include the yellow-casqued hornbill and black spinetail. The park is threatened by farmland encroachment and oil palm plantation development (Ayanlade 2016).
Osse River Park, Ondo State (N7o0’ E5o30’) is 38,235 ha is on the boundary with the Guinean forest-savanna ecoregion. Elephant, chimpanzee, white-throated guenon, and Ibadan malimbe are present. The state government, in cooperation with the Nigerian Conservation Foundation, is in the process of upgrading the area to national park status (Oladeji and Fatukasi, 2017).
Eastern Guinean forests ecoregion
This ecoregion is found in Ghana and Togo. Forests in Ghana are wetter and evergreen. The forest is in isolated patches on the Togo Hills and is semi-evergreen or deciduous. In Togo, typical trees are Milicia (Moraceae), Triplochiton (Malvaceae), Antiaris (Moraceae), and Diospyros (Ebenaceae). The Togo Hills are also known for endemic butterflies. The area around Kpalimé (N6o54’ E0o38’) is known for waterfalls in the forested mountains.
Aledjo Wildlife Reserve, Centrale and Kara Regions, Togo (N9o15’ E1o20’) is 765 ha and features a scenic road cut through a rock formation and dense dry mountain forests of Isoberlinia (Fabaceae), Anogeissus (Combretaceae), Melicia (Moraceae), and Voacanga (Apocynaceae)
Agumatsa Wildlife Sanctuary, Volta Region, Ghana (N7o7’ E0o35’) is near the Togo border. It is noted for Wli Falls, Ghana’s highest waterfall (600 m in four falls and 2 cascades). On the trail to the waterfall, thousands of fruit bats may be seen clinging to the walls of the gorge. It is operated by the Forestry Commission of Ghana. Mount Afadjato is the highest point in Ghana. It is an Important Bird Area.
Fazao-Malfakassa National Park, Centrale and Kara Regions, Togo (N8o50’ E0o45’) includes 192,000 ha of forest patches of the Eastern Guinean forests (Dialium, Fabaceae; Antiaris, Moraceae; Berlinia, (Fabaceae) and lower elevation areas in the West Sudanian savanna (Afzelia, Fabaceae; Anogeissus, Combretaceae; and Isoberlinia, Fabaceae). Three peaks that dominate the park are Mount Fazao in the center and Mount Malfakassa in the north. The Kamassi River drains the park. Between 1987 and 2015 the area of closed canopy forest in the park decreased 40 percent, suggesting overexploitation by local populations due to agricultural expansion, bushfires, and timbering (Atsri et al., 2018). The park is an applicant for Biosphere Reserve status. More than 200 bird species have been recorded in the park, including the white-browed forest flycatcher (Radley and Campbell, 2008). The park adjoins the Kyabobo National Park of Ghana.
Kyabobo National Park, Volta Region, Ghana (N8o24’ E0o38’) is 22,000 ha adjacent to the Fazao-Malfakassa National Park of Benin. The park has a variety of African wildlife such as buffalo, warthog, aardvark, lion, and elephant, as well as the 60-m Laboum waterfall. The tree Talbotiella gendtii (Fabaceae) is endemic to the park.
Missahohe Forest Reserve, Plateaux Region, Togo (N6o55’ E0o35’) contains steep hills and habitat for Antiaris africana (Moraceae) and Melicia excelsa (Moraceae). It is the type locality for the tree frog Hyperolius baumanni.
Tafi Monkey Sanctuary, Volta Region, Ghana (N6o54’ E0o23’) is located near the Togo border and is 28 ha with mona and patas monkeys. It is operated by the Forestry Commission of Ghana.
Cross-Niger Transition forests ecoregion
This ecoregion is in Nigeria east of the Niger River and is mostly low and undulating in relief. A distinct dry season lasts from December to February. This ecoregion has a transition from rainforest in the south to mixed deciduous forest and savanna to the north; however, most of the ecoregion has been deforested. Forests in the south were formerly dominated by Fabaceae and in the north by Meliaceae. The drier sections are dominated by Sterculiaceae, Moraceae, and Ulmaceae. The Nigerian States that extend into the ecoregion include Abia, Akwa Ibom, Anambra, Ebonyi, Enugu, and Imo.
Ogbunike Caves, Anambra State (N6o11’ E6o54’) are a spiritual site. The caves have numerous passages which may be toured from the main chamber, 5 m in height.
Antonio D. Abreu. 2013. Principe Island’s Biosphere Reserve (Democratic Republic of Sao Tome and Principe): A Living Laboratory for Sustainable Development. Pp. 284-302 in Ruida Pool-Stanvliet and Miguel Closener-Godt. AfriMAB, Biosphere Reserves in Sub-Saharan Africa: Showcasing Sustainable Development. Republic of South Africa, Department of Environmental Affairs, and United Nations Educational Scientific and Cultural Organization.
Godfrey C. Akani et al. 2014a. Preliminary surveys of the terrestrial vertebrate fauna (mammals, reptiles, and amphibians) of the Edumanon Forest Reserve, Nigeria. Tropical Zoology 27:63-72. 10.1080/03946975.2014.944376.
Godfrey C. Akani et al. 2014b. Diversity of terrestrial vertebrates in Taylor Creek Forest Reserve, an area of high environmental value in the River Niger Delta (Bayelsa State, Nigeria). Vie et Milieu 64:59-68.
Honam Komina Atsri et al. 2018. Changes in the West African forest-savanna mosaic, insights from Central Togo. PLoS ONE 13(10):e0203999. DOI: 10.1371/journal/pone.0203999.
Ayansina Ayanlade. 2016. Landuse change within Okomu and Gilli-Gilli Forest Reserves, southwestern Nigeria: Its climatic and societal implications. Tropical Ecology 57:193-203.
Neil Burgess, Jennifer D’Amico Hales, Emma Underwood, Eric Dinerstein, David Olson, Illanga Itoua, Jan Schipper, Taylor Ricketts, and Kate Newman. 2004. Terrestrial Ecoregions of Africa and Madagascar: A Conservation Assessment. Island Press.
Sunday Oladipo Oladeji and Damilola Fatukasi. 2017. Participatory approach to conservation and management of protected areas in Nigeria: Case study of Osse River Park project. African Journal of Environmental Science and Technology 11:471-485.
Paul M. Radley and Genevieve Campbell. 2008. The birds of Fazao-Malfakassa National Park, including a first record for Togo of white-browed forest flycatcher Fraseria cinerascens. African Bird Club Bulletin 15:203-213.
Orji Sunday. 2019. Cocoa and gunshots: The struggle to save a threatened forest in Nigeria. Mongabay.com, 19 July. https://news.mongabay.com/2019/07/cocoa-and-gunshots-the-struggle-to-save-a-threatened-forest-in-nigeria/ (accessed April 17, 2020).