In the aftermath of a tsunami, mangrove forests in Indonesia protect lives and livelihoods

On an early December morning 17 years ago, a magnitude 9.1 undersea earthquake triggered 100-feet high waves that slammed into the coast of Aceh in the northern end of Sumatra Island, Indonesia. The 2004 Indian Ocean tsunami, as it became known, killed more than 230,000 people across the Indian Ocean countries, mainly in the Indonesian archipelago.

Neighboring the province of Aceh, a local organization based in Medan, the capital and largest city of North Sumatra, has been boldly charting its way to disaster resilience -- all beginning with a humble mangrove seed. Yayasan Gajah Sumatera (Yagasu), an Indonesian non-governmental organization (NGO) that was set up for elephant and biodiversity conservation in 2001, switched to mangrove restoration after the tsunami.

Under founder and executive director Mr. Bambang Suprayogi’s leadership, Yagasu realized that mangroves can bolster ecosystem-based disaster risk reduction, improve local livelihood, and aid in climate change mitigation and adaptation.

Indonesia has the most extensive mangrove cover in the world, housing more than 20 per cent of the world's mangrove area. Yet years of rapid industrialization and massive land-use changes such as intense oil palm and shrimp cultivation have led to rampant mangrove deforestation. For the past two decades, Yagasu has successfully worked with local and international stakeholders to plant more than 30 million new mangrove trees in 12,300 hectares of degraded areas, spanning Aceh and North Sumatra provinces in the hazard-prone archipelago.

Indonesia sits along the so-called Ring of Fire in the Pacific – a region with several active volcanoes that experiences frequent earthquakes and tsunamis. A 2010 UN Development Programme report on Aceh, the most affected area in the 2004 tsunami, noted that the cumulative impact of constantly recurring events such as earthquakes, landslides, and flooding, leads to a substantial economic and emotional burden on society. Mr. Suprayogi echoed similar views in an interview: “Tackling the continual economic damages from tsunamis and other disasters is the core motivation for Yagasu.”

According to the United Nations Office for Disaster Risk Reduction (UNDRR) report, ‘Ecosystem-Based Disaster Risk Reduction, Implementing Nature-based Solutions for Resilience’, coastal forests like mangroves are capable of managing all dimensions of disaster risks. Mangroves lower damage by absorbing the impact from waves, floods, and rising sea levels through their large above-ground aerial root systems; they help in diversifying sustainable income sources, thereby reducing vulnerabilities, and also limit disaster exposure by acting as natural shields between human settlements and coastal hazards.

Research on the potential of mangroves in reducing tsunami damage is still growing. In the wake of the 2004 tsunami, a study showed that the damage from the tsunami to areas buffered by coastal forests was strikingly less than in areas devoid of tree vegetation.

Mr. Suprayogi pointed to a village in Aceh Besar, a district in Aceh province, that registered minor damage from the 2004 tsunami due to its coastal mangrove forest. He said that the mangrove forest fringing the village was around 200 meters, which cushioned the tsunami’s impact, such that the mangroves, the communities, and their properties survived.

In Yagasu’s experience, restoring mangroves would help in building a green economy founded on sustainable resource management with community participation. The principal factor which helped guarantee sustained community participation in an ecosystem-based disaster risk reduction and economic recovery is the NGO’s success in helping improve family incomes.

Their research found that fishery production increased by 27 per cent once mangrove ecosystems were restored and kept stable over three years. Their planting system imitated natural conditions of mangrove ecosystems, maintaining up to 30 per cent of areas as channels and open water to encourage sustainable aquaculture.

The increase in income is funneled back to support other businesses like revolving microcredit funds. Yagasu has set up cooperatives with various villages to build businesses around organic silvofishery (traditional aquaculture model that combines fishery business with mangrove planting), recreational fishing and eco-tourism, crab fattening (part of crab farming), soft shell crab exports, mangrove foods, and beverages, and more.

“We produce 3 to 5 tonnes of crab every day, and 400 to 500 tonnes of fish every week from the mangrove wetlands. Before COVID-19 hit, we even regularly exported these products to neighboring countries like Singapore,” said Mr. Suprayogi.

In 2011, they collaborated with Livelihoods Funds, an impact investment fund created by private companies, to scale up their projects. Yagasu identified about 10,000 hectares of suitable land for reforestation along shorelines and abandoned fish ponds in Aceh and North Sumatra.

Mr. Suprayogi said that Yagasu’s mangrove restoration projects and livelihood diversification based on the mangroves lifted average monthly family income by 49 per cent during the four years of project implementation (2016 – 2020) from 220 USD to 328 USD per family per month. A World Wide Fund for Nature report suggests an even higher figure of 57 per cent in income enhancement is possible.

Working with local experts, the cooperatives sustainably use every component of mangrove trees to create profitable goods. A unique by-product is an organic ink extracted from mangrove fibers used in the traditional batik dyeing technique. Yagasu works with humanitarian aid agencies to help women set up businesses selling high-quality, organic batik fabric, dresses, and shirts. In a country where female participation in the workforce is 51 per cent, involving and recognizing their capabilities are areas that require sustained attention, emphasized Mr. Suprayogi.

Yagasu’s mangrove restoration for livelihood benefits, which forms the basis of its ecosystem-based disaster risk reduction, is very systematic.

They first identify the different soil characteristics, since these influence the survival of replanted mangrove seedlings. The NGO has an in-house mapping capacity to identify suitable land, thanks to its previous small-scale restoration experience that has polished its mapping capacity. Additionally, committed participation from local communities -- from collecting mangrove seedlings to monitoring growing mangroves -- has been critical to the sustained success of the NGO’s initiatives.

Years of outreach have helped raise public awareness, and also deepened Yagasu’s relationship with the local communities. Many would log the mangroves for firewood or convert the mangrove wetlands into shrimp ponds, rice fields, and palm oil plantations. The NGO regularly conducted meetings and workshops to improve public knowledge, build trust and gain endorsement for its work within village policies.

The positive impact of its initiatives among the coastal communities has led to the widening of Yagasu’s outreach. In Aceh, they have signed long-term agreements with 194 villages and 312 community groups, and also inked short-term deals with six provincial government institutions.

Mr. Rusli, an award-winning conservationist who is a fisherman by profession in the North Sumatran village of Paluh Kurau, backs the success of mangrove restoration and Yagasu’s economic programs that benefit local communities in multiple ways. Mr. Rusli leads a group of local farmers called Serai Mangrove Forest Farmer Group, and began collaborating with the NGO in 2007.

“The mangroves that were planted have now grown high, so they can withstand the pressure from rising sea levels and protect the villages from cyclones as well,” said Mr. Rusli.

Experts in the region, however, warn that mangroves are not silver bullets against tsunami damage. Dr. Daniel Friess, coastal geographer and deputy director at the National University of Singapore’s Centre for Nature-based Climate Solutions, commented that “the evidence on the role of mangroves in protecting against tsunamis is very mixed, and is based on correlations or lab experiments. A lot of studies are refuting earlier claims of their benefit.”

Dr. Frank Thomalla, an independent researcher and consultant in disaster risk reduction and climate change adaptation focusing on the Asia Pacific, emphasizes the need to take a multifaceted view when scaling up nature-based solutions like the restoration of mangroves.

“From a disaster risk-reduction perspective, it’s important to consider that the degree of protection against coastal hazards offered by mangroves will be limited. It may be necessary also to have other protection mechanisms in place. A hybrid approach, of soft and hard defenses, has been gaining a lot of traction and offers multiple benefits such as risk reduction, as well as recreational, amenity, and livelihoods values.”