Mangrove loss threatens community resilience

JAKARTA, 14 June 2012 (IRIN) - Millions of hectares of mangrove forests in Indonesia are being lost to agriculture, oil palm plantations and even fish farms, making coastal communities more vulnerable to the force of tropical storms and the loss of livelihoods and products.

“There’s quite a lot of evidence that mangroves reduce wave and wind energy in relation to storms, and also reduce the impacts of coastal erosion,” said Ben Brown, the Indonesia representative of the Mangrove Action Project (MAP), an international NGO that works to conserve and restore mangrove areas worldwide.

“Where mangroves go missing, villages and shorelines are heavily impacted in relation to storms. Some are inundated with tidal waters, whereas years ago, when mangroves were intact, these villages didn’t suffer from these effects,” he told IRIN.

Indonesia has around 17,500 islands, of which about 6,000 are inhabited by over 238 million people. In 2011 the Meteorology, Climatology and Geophysics Agency (BMKG) detected 23 tropical cyclones off the coast, which produced high-speed winds, heavy rains and heightened tidal levels that caused flooding and structural damage to buildings and coastal infrastructure.

Brown said mangroves are adjacent to all major landmasses and big rivers in Indonesia, and mostly found on the coasts of the large islands of Sumatra, Kalimantan, Sulawesi and Papua.

The island of Java, where approximately 130 million people live, is particularly vulnerable to tropical cyclones, according to the Indonesian National Disaster Management Agency’s 2010-2014 plan.

In January 2012, local media reported that falling trees, landslides and flooding caused by a tropical cyclone had damaged 2,300 homes and killed 16 people on the islands of Java and Bali.

Community protectors

“Mangroves can be short or tall, so waves will be more or less damaging depending upon the height of mangroves,” said Norm Duke, a mangrove expert based in the TropWATER group at James Cook University, Australia. “The only scenario where they can become overwhelmed is where storm surges are associated with a tsunami, but generally they offer protection that would not be otherwise available.”

The forests also support the livelihoods of coastal communities, the Centre for International Cooperation in the Indonesian Forestry Ministry noted. Mangrove palms are used for roofing material, and mangrove wood can be used to produce high-value charcoal and fuel for cooking and heating. Some communities use the bark of certain trees to treat various diseases and skin disorders.

Mangrove trees shelter the habitats and breeding areas of many fish species from storm conditions, making an often vital contribution to the food security and livelihoods of villagers. “The roots of mangroves tend to be stronger than other vegetation,” said Daniel Murdiyarso of the Centre for International Forestry Research (CITFOR), an Indonesia-based NGO. “This, combined with mangrove leaves giving a particular mix of nutrients to fish farms, means that mangroves can be crucial for protecting villages’ fishery habitats.”

In 2007 the Indonesian Forestry Ministry established two centres for mangrove development. During 2010 and 2011 the centre on the island of Bali put in 8,000 new mangrove plants, and the other centre, in the city of Medan on the island of Sumatra, put in 10,000 plants. A further 12,000 plants are targeted for 2012. But will this be enough?

Under threat

Despite their many benefits, the MAP’s Brown says these coastal trees are vulnerable. “The biggest threat is agricultural expansion. In the 1980s there were 4.2 million hectares of mangroves in Indonesia, but by the end of the 1990s more than half of that coverage had been lost due to agricultural expansion, and the current level is unclear.”

He said the Indonesian government’s Fisheries and Maritime Affairs department has budgeted for the conversion of a further 675,000 hectares of mangrove into land for agriculture to meet short-term economic goals, which would remove a third of the remaining mangroves.

Farid Dahdouh-Guebas, a mangrove researcher based at the Vrije Universiteit in Brussels, Belgium, who has conducted research in Southeast Asia, pointed out that “Mangroves may well protect fish farms but, conversely, they are also being deforested to house fish farms. The question is, how many mangroves can you dispose of without losing their protective function?”

Experts highlight the development of oil palm plantations, urbanization and the effects of pollution as further threats to Indonesia’s mangrove forests, and worry that these will reduce the resilience of communities.

Duke of James Cook University said, “Where mangroves have been cut or damaged through harvesting or other reasons, their capacity to protect coastal communities is compromised.”