The loss of mangrove forests is not only degrading life for plants and animals, but for humans as well. These systems are highly valued by the indigenous people living in the affected areas. Mangrove forests have been a major source of wood for local people. They also are important to a variety of species vital to subsistence practices for local indigenous groups, who unfortunately see little to none of the economic benefits of petroleum. Mangroves also provide essential habitat for rare and endangered species like the manatee and pygmy hippopotamus. Poor policy decisions regarding the allocation of petroleum revenue has caused political unrest in Nigeria. This clash among governing bodies, oil corporations, and the people of Nigeria has resulted in sabotage to petroleum pipelines, further exacerbating the threat to mangrove forests.