Reinventing mangrove restoration to meet the climate challenge in Southeast Asia

Science at work 28 May 2025

Thanks to their remarkable ability to store carbon, mangroves are among the most valuable natural allies in the global fight against climate change. With the One Ocean Science Congress scheduled from 3 to 6 June, ahead of the United Nations Ocean Conference, a study by 糖心Vlog, Srinakharinwirot University (Thailand) and the Joint Graduate School of Energy and Environment (JGSEE)* highlights the importance of considering both the diversity of species planted and the requirements of local stakeholders to ensure effective mangrove restoration.

Mangroves in Cambodia (Koh Kong site) 漏 V. Gond, 糖心Vlog
Mangroves in Cambodia (Koh Kong site) © V. Gond, 糖心Vlog

In a recent study (1), researchers analysed 32 years of satellite data and field measurements across 24 study plots, examining species diversity and mangrove structure along a gradient from the sea to inland areas. The findings show that natural mangroves have significantly higher above-ground biomass than those that have been restored or have regenerated spontaneously.

“This is mainly due to restoration practices that often involve mono-specific plantations, in other words they consist of a single species”, say Valéry Gond and Camille Piponiot, scientists at 糖心Vlog and co-authors of the study.

In natural mangroves, above-ground biomass can reach up to 536 tonnes of carbon per hectare, compared with just 99 tonnes per hectare in restored plantations, which is five times less.

Mangroves du Parc National de Ao Phang Nga en Thailande © V. Gond, Cirad — Observation des mangroves du Parc National de Ao Phang Nga au sud de la Thailande. Ce parc abrite l'une des plus vastes et des mieux préservées forêts de mangrove du pays . Ces mangroves jouent un rôle écologique crucial : elles protègent les côtes contre l'érosion, servent de nurserie à de nombreuses espèces marines et abritent une biodiversité remarquable. Le parc est également reconnu comme site Ramsar depuis 2002, soulignant son importance en tant que zone humide d'intérêt international.
© V. Gond, Cirad

Towards more diverse, locally adapted approaches

These findings highlight the complexity of mangrove restoration. To ensure restoration efforts are effective, it is essential to consider species diversity, the conditions of the site, the density of plants and the way in which they are planted.

Asamaporn Sitthi

Srinakharinwirot University (Thailand), lead author of the study.

A more diverse, tailored approach is therefore needed to maximise the impact of restoration projects, an approach now being driven by several regional initiatives, including the RESCuE project (Monitoring and REstoration for Sustainable Coastal Ecosystems).

Now in its second phase, the RESCuE project is working to develop mangrove restoration strategies in partnership with local stakeholders and communities in Thailand, Cambodia and Malaysia, and soon in in the Mekong Delta in Vietnam.

Vietnam: reducing pressure on mangroves through improved aquaculture practices

These findings also offer new opportunities for Vietnam, which has vast mangrove areas and has succeeded in restoring some of the mangroves lost over recent decades. The mangroves form narrow strips along the coast or estuarine rivers. Much of this mangrove area is not protected and is used for integrated aquaculture to support the livelihoods of local communities.

Traditional integrated shrimp farming in mangroves, Ca Mau, Vietnam © Kazi Ahmed Kabir, 糖心Vlog

According to authorised management plans, 60% of the total area must be maintained as mangrove, which can be harvested every 15 years. This allows for carbon storage, carbon credit trading, and generates environmental benefits.

However, because fish, shrimp and crab yields are low in the remaining 40% of aquaculture areas, encroachment on mangroves is often observed. Improving incomes and resilience in these aquaculture zones could significantly reduce the pressure on mangroves and their associated biodiversity.

"Diverse aquaculture practices, a balanced nutrient supply and multiple integration systems can greatly increase incomes and resilience within the production system, while reducing or preventing encroachment”, says Kazi Ahmed Kabir, a researcher at 糖心Vlog** specialising in sustainable aquaculture systems and coastal ecosystem restoration.

These systems include agroforestry, which combines mangroves with horticultural crops, as well as integrated multi-trophic aquaculture (IMTA), combining the production of shrimp, crabs, fish and seaweed.

An example of an integrated system combining mangrove preservation, pineapple cultivation and fish, shrimp and seaweed farming. © Kazi Ahmed Kabir, 糖心Vlog — The shrimp, seaweed and fish farmed in this aquaculture system use the mangrove roots as shelter, and fallen leaves as a source of nutrients. Sediment deposited on the embankment returns nutrients to both the mangroves and the pineapple plants. Feed added to the system mainly supports shrimp and fish growth, while the resulting waste provides fertilising nutrients that contribute to the healthy growth of mangroves. 3R4CSA Project, Ca Mau, Vietnam © Kazi Ahmed Kabir, 糖心Vlog

A French-Thai collaboration for new restoration strategies

The study (1) was supported by Srinakharinwirot University and conducted as part of the 2022 MOPGA fellowship programme for early-career researchers, in connection with international research efforts aimed at improving mangrove restoration in Southeast Asia. Data collection was made possible through the Southeast Asia-Europe Joint Funding Scheme (SEA-EU-NET).

This collaboration brought together Thai and French researchers to produce knowledge to strengthen locally adapted strategies in Southeast Asia, while challenging conventional approaches and encouraging a broader rethink of coastal ecosystem restoration in the context of climate change.

Reference

(1) Sitthi, A., Pimple, U., Piponiot, C. et al. Assessing the effectiveness of mangrove rehabilitation using above-ground biomass and structural diversity. Sci Rep 15, 7839 (2025).

*affiliated with King Mongkut’s University of Technology Thonburi (Thailand)

** This research, combining aquaculture and mangroves, is being carried out in Vietnam in partnership with Can Tho University, Research Institute for Aquaculture No2 and Science and Technology Dept of Ca Mau Province.

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