John Peacock, j.peacock@cgiar.org

The IITA campus is a rich center of biodiversity. Because of the protection and nonexploitation of a patch of secondary forest, lakes, and other natural resources in the area, it represents a wealth of flora and fauna that are not common in other parts of Nigeria.

IITA campus, Ibadan, Nigeria. Image from Google Maps.

IITA was established in April 1967. Earlier in October 1965, approximately 1,000 ha of land were acquired, lying between Ojo in Ibadan town and Moniya villages. The land was covered mainly with oil palms, cassava, maize, cocoyam, and a variety of indigenous trees and climbers.

Today, 43 years on, the area is taken up by research, administration, and residential buildings, lakes, experimental plots, and 350 ha of valuable secondary forest. An arboretum was established in 1979 containing 152 different tree species; 81 of them are indigenous. In addition, the residential and administrative areas of IITA were extremely well landscaped with a diversity of both indigenous and exotic trees. Many of the original hardwood trees were left in situ.

Young Milicia excelsa (Iroko). Photo by J. Peacock.

Although protected, the forest is still a degraded secondary forest. It is basically four layered, made up of a discontinuous emergent canopy dominated by Milicia excelsa (Iroko), Celtis zenkeri, Terminalia superb, and Antiaris africana; a tree canopy made up of Blighia sapida, young Ceiba pentandra, Entandrophragma angolense, and Ricinodendron heudelotii as the more frequent woody plants. The shrub layer is composed mainly of Newbouldia laevis and Baphia nitida with seedlings and saplings of typical canopy emergents such as Mammea africana. The herb layer is highly diverse containing members of the family Orchdaceae and some Poaceae and Chromolaena sp. in the more open areas (Hall and Okali 1978, 1979).

The IITA forest provides a good habitat for a great number of different insects and birds. It is one of the Birdlife International Important Bird Areas (IBA) with 350 species, including the Ibadan Malimbe, Malimbus ibadanensis, which is endemic to this region.

Knowledge about the diversity of butterfly species at IITA is incomplete. A preliminary survey conducted by lepidopterist Robert Warren in 2002−2009 has confirmed the presence of 149 species (See Warren, this issue). This figure is considered low and could be as high as 400.

Pararistolochia goldieana. Photo by IITA.

In December 1987, a group of enthusiastic volunteers from IITA embarked on carving out a nature trail in the forest. Many useful plant species including herbs, medicinal plants, fiber-producing plants, and fruit and timber trees can be seen from the trail. The most spectacular is a climber with a long name and a huge (40 cm diameter and 50 cm length) dark-red flower called Pararistolochia goldieana, which belongs to the family Aristolochiaceae.

The rich biodiversity of the campus is also influenced by its nine lakes. The largest is approximately 70 ha. A dam (The John Craig Dam) was constructed in 1969 and impounds water from the Awba River which runs through the Gunwin watershed. This lake is home to various varieties of fish, aquatic weeds, and birds.

Currently there are many fish in the nine lakes and ponds. Records show that the largest lake was stocked with a wide variety of species. The dominant ones are the African Catfish (Clarias gariepinnus), Nile Perch (Lates niloticus), Slapwater (Heterotes niloticus), and various Tilapines (Oreochromis niloticus, Tilapia zilli, etc.). But a wide variety of other species are present, e.g., Gymnarchus niloticus, Hepsestes odoe, and Channa obscura. There is also a diversity of aquatic weeds, Nuphar spp. (water lily), Azolla sp. (water fern), Potomogeton sp., Typha sp. (bulrush), and Lagarosiphon cordofanus Caspry. L. cordofanus Caspry is uncommon and this may be the only known occurrence in Nigeria (Adeniyi Jayeola, personal communication).

Despite the water and forest habitat, the resident level of mammalian fauna is low. The cane rat or grass-cutter, duiker, mongoose, potto, tree hyrax, civet, and the giant Gambian rat can be seen. Others are the bush-tailed porcupine, squirrels, and small antelopes. Amphibians, lizards, and snakes are also common but have not been studied or documented.

Fruit bats flying over a Ceiba pentandra tree (Yoruba local name: osun papa), IITA. Photo by IITA.

However, there is a large population of straw-colored fruit bats. The flying foxes (Eidolon helvum) form large colonies in the IITA forest. They are the second largest West African bat with a wing span of up to 953 mm. Adults can weigh up to 350 g. They roost conspicuously in the open, covering hectares of treetop branches in the IITA forest and arboretum. An important food for these bats is the fruit of the Iroko tree (M. excelsa). The Iroko produce finger-sized fruits that resemble mulberries. Each fruit contains an average of 80 small, tomato-like seeds which are then transported away from the parent tree. Iroko ranks as one of Africa’s most valuable hardwood trees.

Why is IITA so concerned about its secondary rainforest, indigenous trees, and its rich biodiversity? Deforestation is a serious problem in Nigeria that currently has one of the highest rates of forest loss (3.5%) in the world, translating to an annual loss of 350,000–400,000 ha of forest land (See Ladipo, this issue). Since 1990, Nigeria has lost 6.1 million ha or 35.7% of its forest cover. These figures give Nigeria the dubious distinction of having the highest deforestation rate of natural forest on the planet, and the lowest percentage (2.4%) of rainforest remaining in any African country.

The IITA campus is one of the few reserves in Nigeria where valuable and rare indigenous trees, such as the Iroko, are safe from poachers. Today there is only one specimen of Parkia bicolor in southwestern Nigeria; this one tree is on the IITA campus.

Recently the Director General of IITA, Hartmann, announced that the IITA campus and all it contains will become an African Science Park. This decision is most timely, coming during the International Year of Biodiversity. This will create a more diverse scientific community which could include agriculturalists, ornithologists, lepidopterists, ecologists, foresters, botanists, invasion biologists, and conservationists.

In the future, the IITA campus could be used as a research site for reconciling increasing agricultural production in the tropics and the conservation of biodiversity. IITA has embarked on seed collecting and propagation of indigenous trees to develop an in-situ conservation program for indigenous trees of West Africa. It is also working with scientists at the A.P. Leventis Ornithological Research Institute (APLORI); Centre for Environmental, Renewable, Natural, Resources Management Research and Development (CENRAD); Forestry Research Institute of Nigeria (FRIN); the University of Ibadan; and the Royal Botanical Gardens, Kew to ensure that its rich biodiversity will be conserved for many generations to come. This new initiative at IITA will be used to educate and encourage others in Nigeria to preserve these valuable rainforests.

References
Hall, J.B. and D.U.U. Okali. 1978. Observer-bias of complex in a floristic survey of tropical vegetation. Journal of Ecology 66: 241–249.

Hall, J.B. and D.U.U. Okali. 1979. A structural and floristic analysis of woody fallow vegetation near Ibadan, Nigeria. Journal of Ecology 67: 321–346.