A mangrove is a small tree that grows in the coastal saline or brackish water of intertidal zones or river mouths. In contrast to normal trees, mangroves are salt-tolerant and thrive in conditions which would actually be too toxic for other plants. Another typical feature is their complex root system that is partly exposed to the air. Worldwide, mangroves cover a total area of 150,000 km². They provide breeding grounds for marine animals and balance natural fish and shellfish stocks.
Why are those forests so important for the environment?
1. Mangroves form a natural barrier at the coast, protecting us from natural disasters such as wind, tsunamis and floods. This becomes increasingly important as more extreme weather phenomena occur due to climate change. In order to form a strong barrier, the mangrove forests need to be dense, intact and broad.
2. The complex root system of the mangroves enables them to absorb water after a heavy rain or storm. Soil such as sand and other sediments is stabilised, nutrients are accumulated and erosion is decreased.
3. Furthermore, mangroves filtrate the water and improve the water quality by absorbing nutrients and pollutants from waste water, which might otherwise cause harmful algal blooms. Other ecosystems close to the mangrove forests benefit from this water, including coral reefs and seagrass beds which are important habitats to many species.
4. Mangrove ecosystems contribute to climate change mitigation by carbon dioxide sequestration. They absorb up to 4 times more carbon dioxide than upland terrestrial forests, thus act against global warming through carbon retention. When mangrove forests are lost for example by deforestation, CO² is released and global warming further increases.
How do mangroves improve the life of local communities?
Local communities benefit from mangroves as they are an important source of income and food. The mangroves provide vital products and services that help coastal communities by contributing to their livelihood, well-being and security.
1. Mangroves supply firewood and charcoal which people use for producing energy. The material is also used as construction wood, for example by local residents who build huts, prawn traps and canoes for fishing.
2. Mangroves give people medicines, fibers and dyes. Some mangrove species, for instance, can be used as traditional medicine against inflammation or hepatitis.
3. Mangroves provide people with food as they eat, collect and sell fish and shellfish living in the forests. Moreover, mangroves provide safe breeding grounds for many fish species and are essential to maintain fishing grounds for local fishermen and their families.
4. Mangrove forests are beautiful and full of biodiversity which attracts tourists. Ecotourism can provide local people with jobs, for example as tour guides, drivers, employees in restaurants and hotels, thus generating an income in rural areas.
Why are mangroves endangered?
The threats for mangroves concern many of those special forests on Earth. For this article, we are illustrating them by looking at some examples from our Menabe Antimena project region in Madagascar.
1. An essential threat to the mangrove ecosystem is land and water pollution when local villagers discharge their trash in the mangrove zone and nearby beaches. In addition, waste like plastic particles is washed up from the sea, which is particularly bad since it takes several 100 years for this material to decompose.
2. Overfishing is a global problem and especially relevant in mangrove areas such as the Menabe region in Madagascar. The livelihoods of many local people depend on fishing, but catches have been decreasing in the last decades. This is also threatening the mangrove ecosystem which hosts many different fish species and provides perfect conditions for spawning and offspring nursery.
3. Slash-and-burn-agriculture is a very common method of cultivation in Madagascar. This means that the natural vegetation is cut down and burned off, frequently causing bush fires. If these fires spread, nearby mangrove forests are being destroyed as well.
4. Due to an increasing population in the Menabe region, mangrove resources are threatened by an expansion of agricultural land and unsustainable agricultural practices. For example, more and more mangroves are cleared for rice production on the west coast of Madagascar.
5. Deforestation is a crucial problem as the demand for timber increases and forests are cut down, trying to meet the needs of more and more people living in the areas. They mostly need wood to build houses and canoes or use charcoal to produce energy (especially for cooking in Menabe).
6. The increasing interest of tourists in coastal areas can lead to the clearing of huge mangrove forests, for example when bigger hotels and accesses to the beach are built. Thus, unsustainable tourism can harm the mangrove ecosystem.
Mangroves in Madagascar
Chances for Nature supports the Menabe Antimena Protected Area and its mangroves, which are part of the largest remaining mangrove forests of Madagascar.
Madagascar contains 2% of the world’s mangroves. They are primarily found along the Western coast covering about 1000 km of the coastline. In Madagascar, up to 9 different mangrove species occur (8 in the Menabe region) which form the special mangrove ecosystem that offers a home to many different animal species. The mangrove ecosystem makes a perfect environment that serves as an important fish, crab and shrimp nursery, thus impacting the fish stock in the whole region.
Various endemic and endangered species occur in the mangrove forests of Western Madagascar. Birds such as the Bernier’s Teal (Anas bernieri), the Madagascar Fish Eagle (Haliaeetus vociferoides), Madagascar Heron (Ardea humbloti), Madagascar Sacred Ibis (Threskiornis bernieri) and Madagascar Plover (Charadrius thoracicus) use the mangroves for nesting, roosting and as refuge. In the mangroves of the Menabe region, you can also find one lemur species, the Verreaux’s sifaka (Propithecus verreauxi). Moreover, they are home to a frugivorous bat, the Madagascar Fruit Bat (Pteropus rufus) and the critically endangered Hawksbill turtle (Eretmochelys imbricate).
Find out how we protect the Menabe Antimena Area here.