Invertebrates Flora Botanical gardens Civil societies The mangroves of Sri Lanka are a part of the diverse brackish water plant wildlife of Sri Lanka.The mangrove ecosystem or commonly mangal, is found at the river mouths bordering lagoons, estuaries, or on sheltered shores.Most of the plant material gradually decays and enriches the adjacent waters through detritus food chains.Mangrove clams and oysters are a source of lime and food, as well as fish and crustaceans.Mangrove associates[clarification needed] are largely members of the family Acanthaceae.