Seeing the Plants for the Trees in the Ebo Forest
The rainforests covering the mountainous region from southwestern Cameroon into Nigeria are some of the most biodiverse in the world, and the San Diego Zoo Institute for Conservation Research Central Africa Program has been working to document some of their riches for almost a decade. During the past five years research and conservation work has been based in the Ebo forest, which for a botanist is possibly the most exciting forest in Cameroon because it is the largest of the least-explored blocks of evergreen forest in tropical Africa’s most diverse country for plant species.
With an altitudinal range of 200-1200m, it has large forests of both lowland and submontane (cloud) forest. The forest also contains low hills of bare rock known as inselbergs, or kopjes, home to deciduous woodland and specialist rock species.
The Central Africa Program has been working with the Royal Botanic Gardens, Kew, UK and the National Herbarium of Cameroon since the first expeditions, and immediately began to uncover new species to science of herbs, shrubs and trees. To date new species of Talbotiella, Palisota and Myrianthus are about to be published, while new species of Begonia, Ardisia, Crateranthus, Salacia, Microcos, Costus and coffee relatives Psychotria and Mitriostigma are also being prepared for publication. These are only the tip of the iceberg. So far only a small part of Ebo has been explored.
So why is there such high diversity in the Ebo forest? Yellow-flowered Begonia plants suggest the answer. In Africa, these Begonia species are thought to indicate areas known as ‘refuges’ where forest survived the extended periods of dry weather during the Pleistocene era 12,000 years ago - so indicating areas of very old forest. Mount Cameroon, the highest mountain in Central Africa and famous as a centre of diversity, has six yellow-flowered Begonia species, uncovered over 150 years of botanical survey.
In contrast, at Ebo, we have already uncovered five such species with very little effort, suggesting that there are more to be found, and that Ebo comprises part of an important, and until now, scientifically overlooked refuge area.