The Site is made up of forests, swamps, savannah, waterfalls, caves, valleys and mountainous areas between 800 and 900 metres in elevation. It forms the headwaters of the Nyanga and Ngounié Rivers and their main tributaries. Forest products provide local communities with resources for food, construction, clothing and craft production. The diversity of habitats supports a rich flora and one of the most notable assemblages of animal species in the region. Primates are particularly well represented, with about 20 species recorded in the Birougou Mountains. Species present include the critically endangered gorilla (Gorilla g. gorilla) and chimpanzee (Pan troglodytes), the critically endangered African forest elephant (Loxodonta cyclotis), the endangered African savannah elephant (Loxodonta africana), and the West African dwarf crocodile (Osteolaemus tetraspis). The Site provides essential ecosystem services, including drinking water supply, hydropower generation, carbon storage, climate regulation, and spawning habitat for numerous fish species. It also holds cultural and religious significance, notably through the Bwiti tradition.