The Iroko tree
One tree that stands out above all others in the IITA Ibadan campus is the iroko Milicia excelsa. There are large solitary trees in the fields, on the Golf Course, near residential and administrative buildings, and even in the hotel car park. They were left standing when the original forest was cut down because the Yoruba people regarded them as sacred. Now they are among the last in Nigeria and on the IUCN Red List status as NT (Near Threatened).
Iroko is a forest giant, reaching 50m in height, 10m in circumference and often not branching for the first 20m. It is valued for timber and as an icon of traditional beliefs. In parts of Nigeria, people believe that an iroko was the first tree that God showed to human beings and that it brings forth souls for the newborn. A strong man may be given the nickname Iroko. Medicinal uses are important locally. The bark has analgesic effects, and the gum that oozes from cracks in the bark is a good antiseptic.
Some iroko trees are male and others are female. They are easy to tell apart at the end of the dry season when males produce long dangling catkins and females bear green sausage-shaped fruits that attract hundreds of bats every evening for weeks. An iroko seed is the size of a pinhead. Juvenile trees have soft, delicate leaves and are slow growing. They are very sensitive and need the shade and shelter of the forest. It can take 130 years for an iroko to reach 80cm in diameter so IITA’s lone trees are very old indeed.
The ‘P.g. plant’
Many interesting plants were found in the 19th century by missionaries who went to areas that few Europeans had ever visited before. One such find, made in 1888 by the Reverend Hugh Goldie was Africa’s largest flower, which we refer to as the ‘P.g. plant’ on account of its unpronounceable scientific name, Pararistolochia goldieana.
This spectacular plant is a tuberous climber with large heart-shaped leaves at the top of twining stems about 7m long. It dies down in the dry season and re-emerges as rains begin, forming several trombone-shaped buds near ground level which open in succession. When fully open, the flower measures 60cm long and 30cm wide at the mouth. From its enormous size you might expect the pollinator to be a bug as large as a mouse. More likely its purpose is to disperse the odour of rotting flesh through in the still, humid air of the rainforest.
Like many rainforest species, the P.g. plant needs shade, shelter, and high humidity. The IUCN Red List assesses it as VU (Vulnerable). Without the forest for protection, its days are numbered.
The Ibadan Malimbe
Destruction and fragmentation of habitats pose a significant threat to many bird species in Nigeria. Those with restricted ranges are especially vulnerable. As the name suggests, the Ibadan Malimbe Malimbus ibadanensis occurs only in and around Ibadan. This member of the weaver family is one of only four endemic birds in Nigeria and the only one to depend on the forest. It is assessed as EN (Endangered) on the IUCN Red List due to its small area of distribution, loss of habitat, and declining population.
In addition to its rarity, it is elusive. There were no records between 1980 and late 1987. A survey by the Royal Society for the Protection of Birds (RSPB) and the Nigerian Conservation Foundation (NCF) from 1999 to 2002 indicated an estimated population of around 2500 individuals – a contraction of 66% since the 1970s. The most recent records within the IITA Ibadan campus were in 2016 but the current population is unknown.
The Tree Pangolin
Pangolins are extraordinary animals in habits and appearance. Though they look like ant-eaters and armadillos their closest relatives are carnivores, such as cats, dogs and bears. They feed on ants and termites by means of a sticky tongue which is as long as the entire body. It is estimated that one pangolin consumes 70 million a year. Their underparts are hairy but the rest of the body is covered with tough, overlapping scales. When alarmed they roll into a tight ball which may protect against predators but not hunters. There are only eight species in the world – four in Asia and four in Africa – and all are endangered through loss of habitat, hunting for bush meat, and demand for their scales which, though made of keratin – the same substance as our hair and nails – are believed in Asia to have medicinal properties.
The white-bellied or tree pangolin Phataginus tricuspis is found in the IITA Forest Reserve. It measures 60-100cm long from nose to tail but is not often seen as it is nocturnal and sleeps in a burrow or hollow tree during the day. Females give birth to a single young that rides on the mother’s tail for the first few months. This harmless and environmentally useful animal is on the IUCN Red List as VU (Vulnerable).
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