Madagascar mangroves

The Madagascar mangroves are a coastal ecoregion, in the mangrove forest aquatic biome, of mangrove swamps in rivers and estuaries in Madagascar, mainly on the west coast.

Location and description

The mangrove swamps are located in flat coastal areas where the ocean tides wash salt water high into the mouths of rivers which are bringing nutrient-rich soil down to the coast. For mangroves to thrive there also needs to be some natural feature such as hilly terrain or a coral reef to shelter the coast from ocean storms and the monsoons. In Madagascar they are mostly found on the more sheltered west coast and the largest areas are in the estuaries of the Betsiboka River (in Bombetoka Bay near the city of Mahajanga), Besalampy, and the Mahajamba, North Mahavavy and South Mahavavy Rivers, and near Maintirano. As well as being home to a rich variety of birds and fish the swamps also hold river estuaries in place and prevent river mud being washed into the sea and thus suffocating coastal coral reefs. The climate is warm all along the coast but more humid in the north.

Flora

The mangrove trees found in Madagascar are mainly rhizophoras, (rhizopora mucronata, black mangrove bruguiera gymnorrhiza and ceriops tagal), white mangrove (avicennia marina), and donneratias (donneratia alba) and (lumnitzera racemosa). The mangrove trees are host to other plants such as ferns and mosses. There are some endemic plant species.

Fauna

Mangrove swamps, here in Madagascar and around the world, are an important habitat for wildlife, they are a vital breeding ground for many species of fish and a feeding place for migratory birds. The waters of the Madagascar mangroves are rich in fish and other sea creatures such as molluscs, crabs, which in turn are food to waterbirds, and animals such as crocodiles, green turtle (chelonia mydas), hawksbill turtle (eretmochelys imbricata), and dugongs. Birds include waterbirds such as African spoonbill, great egret, sakalava rail and grey heron, and birds of the forest such as olive bee-eaters. Much of this wildlife is endemic to Madagascar. The many fish found in the waters include mullet, serranidae, carangidae, halfbeak, plectorhinchus and elops machnata

Threats and preservation

Mangroves are vulnerable to clearance for timber, urban expansion, agriculture such as rice growing, industrial development and for dumping of sewage including salt-panning and shrimp cultivation. Urban areas near the mangroves include Tulear, Mahajanga, Maintirano and Morondava. The waters are over-fished. Protected areas exist, in either National Parks or through locally managed marine areas (LMMA).