No nation in history has ever protected all of its mangrove forests and the island nation of Sri Lanka is to become the first one to do so.
A new scheme backed by the Sri Lankan government, which will cost US $3.4m over five years, aims to protect all 8,800 hectares (21,800 acres) of existing mangrove forests by providing alternative job training, funding microloans to people in exchange for protecting local mangroves forests. It also involves a replanting project, which aims to replace 3,900 hectares of mangroves that have been felled.
Mangrove forests are found in saline coastal sediment habitats of tropical and subtropical tidal areas. These dense forests protect coastal areas from erosion, storm surge (especially during hurricanes) and are believed to have reduced the casualties of tsunamis in human settlements bordered by mangrove forests. These plants are able to survive in these saline environments due to their filtration systems that keeps out much of the salt and a complex root system that holds the mangrove upright in the shifting sediments where land and water meet.
These massive root systems are efficient at dissipating wave energy and slow down tidal water enough so its sediment is deposited as the tide comes in, leaving all except fine particles when the tide ebbs. In this way, the intricate root system of mangroves become their own ecosystems and often act as a nursery marine region for juvenile organisms. Sri Lanka has 21 species of mangrove, making it a global hotspot for mangrove biodiversity
Because of the uniqueness of mangrove ecosystems and the protection against erosion they provide, they are often the object of conservation programs, including national biodiversity action plans.
The Sri Lankan government is a joint partner overseeing the measures of this conservation scheme, alongside global NGO Seacology, and Sri Lanka-based Sudeesa, which was formerly known as the Small Fishers Federation of Lanka.
Speaking to the BBC, Seacology executive director Duane Silverstein explained how the scheme will be achieved through a combination of laws, sustainable alternative incomes and mangrove nurseries.
“It is also very significant considering the importance of mangroves as a means of sequestering carbon. It is not only that mangroves sequester an order of magnitude more carbon than other types of forest, but it is sequestered for so much longer.”
Mangrove trees sequester carbon (take CO2 out of the atmosphere and pack it away, for millennia or more) in the top few metres of soil, which is primarily an anaerobic environment – without oxygen. As a result, the microorganisms that usually lead to the decomposition of organic material are not present, meaning the carbon remains locked in the environment for longer. This high-carbon storage suggests mangroves may play an important role in climate change management.
The biodiversity and abundance of marine organisms that inhabit mangrove ecosystems (including fish, crustaceans and molluscs) have also provided livelihoods and nutrition for millions of small-scale fishermen and their families for generations, allowing coastal communities to sustain themselves. Two-thirds of Sri Lankan protein comes from fish, and 80 per cent of the country’s fish come from coastal lagoons sustained by mangroves.
However in the past there has been indiscriminate exploitation of mangroves for commercial, industrial, housing needs mainly due to the lack of knowledge of the ecological role of the mangroves amongst the decision-makers.
Speaking to the BBC, chairman of Sudeesa, Anuradha Wickramasinghe said: “People live in these areas because they depend on the mangroves because a lot of the fish they catch come from mangroves.
But he added: “Shrimp farmers have been either legally or illegally cutting down mangroves.
Farmed shrimps, or prawns, account for more than half of the global demand for the crustaceans. A UN report published in November 2012 warned that the growing demand for prawns meant that valuable mangrove forests were still being felled or were under threat of being felled.
Recently, mangroves have experienced rapid deforestation worldwide — a 30-50 percent decline in the past 50 years. Mangrove deforestation generates greenhouse gas emissions of 0.02-0.12 petagrams of carbon per year, which is equivalent to up to 10 percent of carbon emissions from global deforestation 2.
Vast tracts of mangrove forests have been cleared to make way for the establishment of coastal shrimp farming facilities, especially in the north western coastal belt in Sri Lanka. One tragic irony of industrial shrimp aquaculture is that the process requires clean water, yet it has become a source of severe water pollution. The often unrestricted use of chemical inputs, such as antibiotics, pesticides and water additives, when combined with the buildup on the pond bottoms of unused feeds and feces, has led to epidemic shrimp diseases and many early pond closures because of harmful accumulation of toxic effluents 1.
Without mangroves, fishing yields from nets cast in Sri Lankan lagoons have fallen from a typical 20 kilograms a day to about 4 kilograms 3.
Mr Wickramasinghe says: “Shrimp farming results in a significant fall in fish catch yields, so fishermen are losing income so it costs them their livelihoods.
“So they know about the importance of mangroves and they are keen to protect them.”
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