Mangroves are among the world’s most dynamic ecosystems. But increasing encroachment by development and industry means they are also among the most at risk. They are being destroyed at rates 3-5 times greater than average rates of forest loss. Over a quarter of the world’s original mangrove cover has already disappeared. One of the main threats to mangroves is from habitat destruction for coastal development and aquaculture. For example, in the Philippines alone, over 50 per cent of mangroves have been lost since 1918, largely as a result of the establishment of aquaculture ponds. Pollution and over-exploitation are also reducing the ecosystem services provided by mangroves. Changes in local water conditions caused by upstream dams, irrigation and pollution have led to the loss of many mangroves. Rising sea levels are a longer-term challenge.

 

Mangroves host a spectacular diversity of flora and fauna. They ensure food security for local communities. They provide forest products and sustain fisheries – with some 75 per cent of commercial fish species spending part of their lifecycle in these coastal wetlands. They protect coastlines from erosion and extreme weather events, and contribute to water quality by filtering out nutrients and sediments. They also fight climate change - with global mangrove forests sequestering as much as 22.8 million tons of carbon each year. Fortunately, there is growing recognition that the earth and humanity simply cannot afford to lose these vital ecosystems.

 

Did you know?

• Mangroves are found in 123 nations and territories, but represent less than 1 per cent of all tropical forests worldwide, and less than 0.4 per cent of all global forests.

 

• Management and restoration of mangrove ecosystems is an achievable and cost-effective way to help ensure food security for many coastal communities. 

 

• Mangroves are rich in biodiversity. They provide a valuable nursery habitat for fish and crustaceans; a food source for monkeys, deer, birds, even kangaroos; and a source of nectar for honeybees. They support complex communities, where thousands of other species interact.

 

• Mangroves act as a form of natural coastal defence: reducing erosion, attenuating waves (and tsunamis) and reducing the height of storm surges.

 

• Mangrove soils are highly effective carbon sinks.  They are among the most carbon-rich tropical ecosystems globally, and can contain more carbon per square metre than tropical rainforests. On average, they store around 1,000 tons of carbon per hectare in their biomass and underlying soil.

 

• If destroyed, degraded or lost these coastal ecosystems become sources of carbon dioxide and contribute to global warming.

 

Information by ONU ENVIRONMENT

Photo Credit Mangroves in Ko Lanta, Thailand ©: GRID Arendhal, Peter Prokosch, 2014