Mangrove swamps can be found where a river meets the sea. They are coastal wetlands that are typically found in tropical and subtropical regions. The mangrove trees that make up these swamps are adapted to living in brackish water, where freshwater from the river mixes with saltwater from the sea. This unique ecosystem is important for protecting coastlines from erosion, providing habitats for a variety of plant and animal species, and serving as a nursery for many fish and shellfish species.