The Bas Ogooue (lower Ogooue basin) comprises a vast alluvial plain (some 200 kilometres long and 70km wide), with marshes, lakes and rivers in the west of the country. Luxuriant vegetation covers half of the Site in dense forest, riparian marshes and savannah. It supports several threatened species such as gorilla, chimpanzee, elephant, buffalo, mandrill, African manatee and hippopotamus. Other noteworthy species include waterbirds such as herons, African cormorant and falcons, and fish populations including tilapia and carp. The rich natural resources of the Site are commonly used by local populations for various purposes, some of which are uncontrolled and may threaten the ecosystems. There is no specific management plan, but local regulations aim to protect and maintain the natural resources and ecosystems. A National Park and Biosphere Reserve are being developed.