Mangrove restoration in Indonesia strengthens coast and community

There is more to nature than meets the eye. Mangroves, for example, are not just some trees and bushes, but a powerful protective layer between sea and land. Their roots retain sediment and inhibit erosion and flooding. Moreover, mangroves act as nurseries for numerous underwater animals. As a result, they are essential to the livelihood and food security of local inhabitants. However, in coastal regions like Demak, many mangroves have disappeared due to climate change, deforestation for aquaculture expansion and subsidence caused by excessive groundwater withdrawals. The result? More coastal erosion and flooding, and declining a livelihood security.

Green belt

In many areas where mangroves are disappearing, the remaining traditional 'gray' infrastructure solutions, such as dikes, offer insufficient protection against flooding. Mangrove planting does not work well either: less than twenty percent survive. That is why Building with Nature (BwN) Indonesia (2015-2021), implemented by Wetlands International and EcoShape, took a different approach. Together with residents of Demak, BwN Indonesia placed semi-permeable structures made of materials such as bamboo and nets along the coast. These structures trapped sediment, allowing mangroves to recover naturally. The result: 119 hectares of mangrove forest have been restored, forming a "green belt" along 23 kilometers of coastline. This leads to less erosion and flooding and more water purification, carbon storage and biodiversity. For example, several fish populations and already 66 bird species benefit from the restored landscape.

" Over 30 million people in Java are at risk. Conventional interventions weren't successful. So, we created a coalition that would harness nature and the community to heal and restore our environment." Fegi Nurhabni, deputy director for Disaster Mitigation and Climate Change Adaptation (Ministry of Marine Affairs and Fisheries of the Republic of Indonesia)

Participation, training and awareness

What makes the project special is the intensive cooperation with villagers and farmers. From the beginning they thought and worked on the design and construction of the semi-permeable structures. Through joint management groups and the Bio-rights system (see below), residents themselves were given responsibility for construction and maintenance. In so-called Coastal Field Schools, residents learned why mangroves are important for coastal protection and aquaculture. In addition, they received training in Associated Mangrove Aquaculture (AMA): a sustainable production method that uses mangroves as natural breeding grounds and thus produces higher aquaculture yields than traditional cultivation. By leveraging local knowledge, residents further developed AMA together. This focus on participation and co-creation created broad support and strong ownership. This created a group of ambassadors who, in turn, spread their knowledge and local enthusiasm further.

Bio-rights

The project directly linked mangrove restoration to economic benefits for local communities. A new Bio-rights fund provided loans to local communities for the construction and maintenance of the semi-permeable structures. Did they indeed implement the sustainable aquaculture methods and did the ecosystem recover? Then the loan was converted into a grant. As aquaculture pond owners as well as local governments, international funds and NGOs contributed financially to Bio-rights, shared ownership emerged. Analyses show that the benefits of the measures, from secured productive land to income growth and avoided damage, far outweigh the costs, with an estimated payback period of five years.

Future prospects

The effects for residents of Demak are felt in many ways. Mangrove restoration and sustainable aquaculture tripled their incomes. Improved food security and more stable livelihoods strengthened confidence in the approach. At the same time, the project increased social cohesion: residents worked together on design, maintenance and decision-making. Women also explicitly participated in the project, which strengthened their position within the communities. Furthermore, through Bio-rights, the project encouraged alternative sources of income, such as ecotourism and seaweed. This not only improved the coast, but also the future prospects of its inhabitants.

"Since learning the new techniques, we have tripled our incomes. Before, our husbands mostly ran the fish ponds, but now women are much more involved." - Siti Amanah, Demak resident

From village to ministry

The success of the project is largely due to the cooperation of a diverse and international network. National and local governments got involved early on, thus ensuring political clout. At the same time, NGOs, knowledge institutions, hydraulic engineering and consulting companies and villages contributed their knowledge and practical experience for research and implementation. Thus this public-private partnership combined diverse expertise for the development and application of innovative mangrove restoration. This created broad support, at all levels: from village to ministry.

Hybrid approach

Semi-permeable structures offer great prospects for coastal protection. Their success depends on regular maintenance and thus on strong local ownership. However, sea level rise and subsidence caused by groundwater extraction can undermine their effectiveness. That is why it is important to keep learning, adapting and improving. And to cleverly combine green measures where necessary with gray infrastructure such as dikes. So a hybrid approach, tailored to local circumstances. This approach offers opportunities, for example, for the Giant Sea Wall proposed by the Indonesian president: a line of defence along the Javanese north coast.

Demak teaches us that coastal protection should prioritize nature-based and hybrid systems whenever possible. Mangrove forest restoration can provide a self-sustaining and adaptive first line of defence. Traditional "gray" infrastructure solutions, such as levees, should be designed to support, rather than replace, these natural processes.

Award winning project

Demak provides inspiration and opportunities for tropical, muddy coastal areas worldwide. It shows that mangrove restoration is a cost-effective NbS that contributes to both coastal protection, food security and economic growth, especially when combined with systems such as Bio-rights and AMA. The success did not go unnoticed: the project won one of ten UN Restoration Flagship Awards. The Indonesian government has also incorporated the techniques developed into national guidelines for mangrove restoration. At least 15 other coastal districts and islands are now applying these semi-permeable structures. Demak also serves as an example internationally. For example, the principles are being applied and further developed in the Philippines.

Working together with each other and nature

Above all, this Building with Nature project inspires a different way of thinking, working with nature to strengthen both ecosystems and local communities. Here you see the power of a nature-based approach as an answer to multiple societal challenges, made possible by international cooperation and a central role for residents.
Demak also shows how Dutch companies,NGOs and knowledge institutions can contribute to the development, application and sharing of NbS through programs such as NL2120. This makes the project a great example not only for coastal regions worldwide, but for everyone working on solutions that protect both nature and people.

Authors: Thomas Westhoff, Elianne Dummer, Marlies van Ree, Daan Verstand

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