It is also characterized by a wide range of biotopes, from lowland and mountain forests, to mangroves and savanna area, which contribute to its unique ecosystem.

[6] The WWF has listed the forests of the national park as among the Global 200, the 200 most important biological areas on the planet.

[7] The forest of Obo is listed as an Important Bird Area (IBA) of Africa.

[3] The park has been recognised as an Important Bird Area (IBA) by BirdLife International.

[3] Invertebrates include the moths Theretra viridis, Hyalobathra barnsalis and Pseudoclanis tomensis and the ant Tetramorium renae.