….Sam Oluwalana, Ibadan
A 20-year project that protects and manages remnants of decrepit forests in a corner of the Republic of Benin in West Africa has resulted in a biodiversity-rich secondary forest, preserving its most important inhabitants, the critically endangered, endemic red-bellied monkey, Cercopithecus erythrogaster (Cercopithecidae) [at right] and 52 other endangered plant species of economic importance to Africa.
The outcome of the project, which was carried out in the Drabo Gbo forest of Southern Benin by IITA’s scientist Emeritus, Peter Neuenschwander and Aristide Adomou, a scientist from the University of Abomey-Calavi, Cotonou, Benin, was published recently in the open access journal Nature Conservation with the title Reconstituting a rainforest patch in southern Benin for the protection of threatened plants. The project sought to link and rehabilitate small remnant forests and young fallow and agricultural fields to develop a 14-hectare forest reserve through selective management by encouraging forest regrowth and introducing plants from other forest islands of southern Benin.
Drabo Gbo is a village of about 500 inhabitants at the southern edge of the Allada Plateau, 30 km north of Cotonou, Benin’s capital. The rehabilitated forests are so rich in biodiversity and now rival that of natural rainforest remnants in the region. Four forests within the Drabo Gbo forest are sacred and host diverse species of butterflies, birds, and endangered species of monkeys, trees, and snakes, among others.
In Africa, about 22 percent is forest and woodland, and only a small percentage of this acreage is protected. Incredibly important from a human standpoint because of their timber and water resources, these tree-dominated ecological landscapes are also reservoirs of outstanding biological diversity. The maintenance of such managed islands of biodiversity is therefore critical considering the impact of human activities over the years that have led to the destruction and loss of such diversity.
The researchers—over the 20-year period—had carefully protected, managed, and encouraged fallow vegetation, removed exotic timber, and introduced 253 species of native plants as seeds and young plantlets collected in the few remaining rainforest patches in southern Benin. Today, the resulting reconstituted forest harbors about 600 species of plants and creates a sanctuary for many animals.
Currently, 224 tree species are growing on the 14 hectares. Among them, 69 are big trees of 10 m height or more. In the Drabo Gbo forest, the number of Cola gigantea (giant cola), which had been largely destroyed in the area, increased steadily under total protection. The timber trees Afzelia africana (African mahogany), Celtis mildbraedii (Red-fruited white stinkwood), Diospyros mespiliformis (African ebony), Milicia excels (African Teak, Iroko), Triplochiton scleroxylon (obeche), and Trema orientalis (pigeon wood), which had all disappeared from Drabo, now grows well in the protected area. Erythrophleum suaveolens (sasswood tree) raised from seeds has become common and reached 25 m, while Rhodognaphalon brevicuspe planted as sticks has reached 22 m.
“The forest already serves as a reference for the region, and is intended to become an educational and research center maintained by IITA. This project demonstrates that by involving the surrounding population and by appealing to their local customs and traditions, the security of such an exposed forest in a densely populated area can be assured,” Neuenschwander said.
Neuenschwander, in sharing the results from his work stated: “I am pleased to tell the world that this study has proved that with relatively modest means, but much patience and perseverance, it is possible to restore, even create de novo, a rainforest. The techniques to do this have been available for a long time.”
These findings reveal that with 585 plant species or about 20% of the flora of Benin, the Drabo Gbo forest has saved plants that might have otherwise disappeared from Benin. The forest has now become a sanctuary, not only for monkeys, but also for rare plants, which provide the basis for the launch of rare butterflies and other species. Similarly, the area’s proximity to big towns and the relatively easy access could offer some eco-touristic development.
The authors point out that what is needed now is “action to create a network of protected forests with exchange of species and local rehabilitation to round up the area of forests and to fill holes created by earlier logging.” Most importantly, they contended that the local populations have to be involved in managing these forests and see the advantage of such forests or at least not oppose their creation.
Ownership of the Drabo Gbo forest had been transferred to IITA to consolidate sustainability and to continue biodiversity studies. IITA maintains another important forest patch, a 350-hectare secondary forest, in its headquarters in Ibadan, Nigeria. The forest represents a wealth of flora and fauna that are not common in Nigeria, and also serves as an important link to the ongoing conservation of biodiversity resources in the region.