Salt is precious in poverty-stricken coastal West Africa, but conservation experts say efforts to extract it are laying waste to mangrove swamps, causing erosion and ravaging fish stocks.

In Sierra Leone, one of Africa’s poorest nations still recovering from a 1991-2002 civil war, lawmakers are preparing a bill to join a seven-nation charter to protect the region’s mangrove forests.

Conservation group Wetlands International says the initiative is essential for West Africa to save the 800,000 hectares (2 million acres) of mangrove swamps it has left, less than a third of the 3 million hectares it started with.