Tracking how investments in mangrove conservation yield great pay-offs

While over 1 million hectares of mangroves have been lost since 1996, the trend of mangrove loss is decreasing. This is good news, yet due to mangroves’ outsized importance for the environment and local and national economies, it’s not enough to just stop their decline. We need to reverse it.

This is why the Global Mangrove Alliance (GMA)’s latest report on the global state of mangroves set a range of goals for 2030. They include:

• Restoration of half of all global mangrove cover losses since 1996
• Reduce net mangrove losses due to human actions to zero
• Increase areas under conservation measures from 40% to 80%

Realizing these goals requires a refined understanding of mangrove loss and protection patterns and actionable monitoring tools.

To this end, the GMW, including solo Earth Observation, The Nature Conservancy, Wetlands International, and Aberystwyth University, have worked with Vizzuality to create and upgrade Global Mangrove Watch (GMW), the primary global platform for monitoring mangroves, with a slate of new and expanded features to demonstrate mangroves’ conservation value and to track their conservation progress and threats accurately. Together, these maps and data visualizations illustrate why mangroves are one of our best hopes in the fight against climate change and biodiversity loss.

Key takeaways from this blog:

1. The current state and role of mangroves
2. What are the most crucial mangrove regions to track?
3. The reasons behind mangrove cover loss
4. The economic, social, and environmental impact of mangroves
5. What does investing in mangroves mean for our future?

Mangroves are a key element in monitoring and protecting terrestrial and marine ecosystems, with an enormous mitigation potential against climate change and huge value for local communities. Global Mangrove Watch helps put all the different aspects of value and protection into perspective, with up-to-date, reliable data and near real-time monitoring, according to GMW-developer and Vizzuality scientist Ángel Arcones.

State and significance of mangroves

“When we see the other mapping tools, for everything from tree cover to fishing, and we consider the incredible value mangroves have in building resilience to climate change, creating a platform that accurately tells the global story of mangroves is a no-brainer,” explains Wetlands International’s Senior Technical Officer Lammert Hilarides.

Indeed, mangroves serve a vital function as ecosystems of hope. On a global scale, as one of the most productive ecosystems in the world, they have the potential to store CO2 equivalent to half of the annual global carbon emissions stemming from human activities such as burning fossil fuels and land-use changes.

They also play a significant role in countering flooding events, coastal erosion, and marine biodiversity collapse, filtering water, and providing food for millions of people.

Many populations like those living along the Maramasike Passage in the Solomon Islands depend on mangroves for food, income and housing materials in the Solomon Islands. (Wade Fairley, 2012/Flickr/ CC BY-NC-ND 2.0 DEED)

Important regions

GMW allows us to learn about the distribution of all 64 mangrove species on Earth. Indonesia proudly hosts 47 of them. It is also the country with the largest extent of mangrove habitat, with 29,000 km² covering around 43% of its coastline. To put that into perspective, Indonesia is home to mangroves extending across a total cumulative area the size of the entire nation of Armenia.

Southeast Asia is the world’s most mangrove-rich region. Aside from Indonesia, Myanmar and Malaysia, followed by Papua New Guinea, the Philippines, Thailand, and Vietnam all host substantial and diverse mangrove habitats ranging from 2,000 km² to 5,000 km² in total extent.

Unfortunately, most mangrove forests across Southeast Asia remain vulnerable as they are not protected. Only Cambodia and Vietnam stand out as countries close to, or more than, half of all mangrove forests are located in areas with some protection. With more mangrove cover left to protect than any other region, Southeast Asia should be at the front and center of global mangrove preservation efforts to meet GMA’s 2030 goals.

Indonesia’s 25% and the Philippines’ 33% protected mangrove areas reach close to 10,000 km². The mangrove conservation potential in these countries, as well as Papua, Myanmar, Malaysia, and Thailand (most of which don’t even safeguard 10% of their mangrove coastlines), is very high but at risk due to scattered and limited overall coastal protection areas.

Although East African countries’ total coastlines may be smaller than those of major Asian nations such as Indonesia or Malaysia, more than 50% of the coasts of Mozambique, Tanzania, and Kenya are mangrove habitats. Africa’s largest island nation, Madagascar, hosts nearly 2,800 km² of mangrove forests, while Mozambique is home to the biggest and most diverse East African mangrove habitats.

Tanzania (82%) and Mozambique (53%) protect more than half of the areas where mangroves can be found. Kenya has put more than a third (36%) of its relatively small mangrove coastline under some form of protection.

The vast majority of mangroves in Tanzania are located in protected coastal areas. Given their significant blue carbon sequestration potential, the country’s efforts to safeguard mangrove ecosystems and coastal peatlands will likely boost its attempts to meet its NDC requirements.

That being said, East Africa has still seen a 4% loss of mangrove cover from 1996 to 2020 due mainly to unsustainable wood extraction, land clearance for agriculture, and the impacts of cyclones and flooding. Still, various conservation efforts in the region, such as those initiated by local communities in Kenya involving communities in reducing pressure on these coastal forests, offer a glimpse of hope that mangrove habitats may regrow and spread to their original extent.

Madagascar and Somalia are the struggling candidates for mangrove protection in East Africa. Although these low-income countries have many social, economic, and environmental problems, they still manage to protect a higher proportion of their mangrove coastlines than several Southeast Asian countries.

The Greater Caribbean comprises more than 25 countries and European overseas territories, all of which are home to diverse mangrove habitats. Some of these wetlands host the world’s richest mangrove-associated invertebrate fauna and provide habitat for many globally endangered animal species. Mexico’s Caribbean coast is lined by more than 6,600 km² of mangrove forests, while countries such as Cuba (3,500 km²) and the Bahamas (1,500 km²) are also home to major mangrove habitats.

Many varieties of mangroves can be found across all Caribbean nations. The Bahamas and Cuba both protect more than 50% of their mangrove coasts, but this does not prevent mangroves from suffering from significant oceanic event impacts. Mexico, the Dominican Republic, and Jamaica all safeguard more than 70% of their mangrove forest cover, while Martinique and Guadeloupe are closing in on 100%.

Mangrove forests in most countries in the Greater Caribbean are located in areas with some or even significant protection status, often preventing or reducing the negative effects of many drivers of mangrove decline. Still, oceanic disturbances such as storms can devastate mangrove ecosystems there.

Reasons for mangrove decline

In Southeast Asia, mangrove cover loss is primarily driven by commodities, that is, the conversion of mangrove habitat to agriculture and aquaculture. As the largest mangrove habitat on Earth, Indonesia’s net loss of 1,700 km² in mangrove forest cover between 1996 and 2020 points to a significant expansion of activities in the country’s food production sector, translating to a loss of 5.8% of its previous mangrove habitat. This decline is notably higher than the average rate worldwide for the same (3.4%). Myanmar also lost more than 5% of its mangroves since 1996, while Malaysia and Papua have fared better. Reversing these trends will be critical to reach the GMA’s 2030 targets.

In Indonesia, mangrove decline has largely been driven by the expansion of fish and shrimp farms. If the country were to stop mangrove destruction entirely, it could meet one-fourth of the government’s 29% emissions reduction target for 2030.

Across the Indian Ocean, in East Africa major challenges to mangrove conservation include inland topsoil erosion from agriculture and grazing, which is burying mangrove roots and affecting their survival. Additionally, industrial pollution, urbanization, and varying human population pressures are impacting mangroves differently across the region, with some countries, especially Madagascar, relying heavily on mangroves for fuelwood while others, like the Seychelles, have lower dependence. At the same time oil pollution from tanker routes along the East African coast is causing mangroves to suffocate.

In short, reducing non-productive conversion, erosion, and episodic disturbances throughout East Africa could mitigate the three drivers that together account for more than 80% of the mangrove loss in the region and up to 97% in Kenya and Mozambique.

In East Africa, non-productive conversion, erosion and episodic disturbances, is the primary cause of mangrove cover loss. However, proportionally, Tanzania, Kenya, and Madagascar have lost very little of their mangrove covers, with Mozambique being the only East African country with a loss of more than 5% since 1996.

The mangroves in the area of Lamu on the Indian Ocean coast of North-East Kenya, close to the border of Somalia, are known as some of the most extensive and species-rich along the entire coast of East Africa. They are, however, threatened by the construction around the newly built second port of Kenya north of Lamu, the ancient trade center of the Lamu Archipelago. (Peter Prokosch/ CC BY-NC-SA 2.0 DEED)

Mangroves in Mexico, Puerto Rico, the Dominican Republic, and Jamaica share the burden of non-productive conversion with those located in East Africa, often due to tree cutting for firewood or charcoal. Mexico’s overall loss rate of 4.5% includes both the Pacific and Caribbean mangroves, but mo. Still, most states from Bermuda to Jamaica and Puerto Rico to Grenada have experienced minor overall mangrove cover loss.

Overall, the major threats impacting mangrove ecosystems’ health care in the Caribbean urbanization, damming, agriculture, forestry, tourism, fisheries, salt production, and shrimp farming.

But this is only half the story. Erosion due to ocean processes such as rising sea levels and coastal degradation caused by storms and waves is the primary factor for mangrove decline in other Caribbean nations, primarily Cuba and the Bahamas. The impact has been significant: The Bahamas has lost 150 km² or 10% of its total cover, while Cuba has lost mangrove forest habitat almost twice that size, accounting for 8% of its total cover. To put that into perspective, the GMA wants to prevent a similar extent of mangrove loss by 2030, 168km² of mangrove habitat.

Economic, social, and environmental services of mangroves

Mangroves may suffer from extreme weather events and oceanic processes, but if we conserve them, they provide coastal protection against storms, flooding, and erosion. In Southeast Asia, one of the most populated areas on the planet, mangroves protect millions of people against storms of all intensities.

By integrating and visualizing data from recent studies into GMW, we can see that Southeast Asian countries — most notably Vietnam — benefit from mangroves’ function as barriers protecting people from storms. With much of its land near the ocean and most of the population living in coastal areas, mangroves safeguard between 6 and 8 million people against different storm scenarios in Vietnam, depending on the intensity of the storms. For Vietnam, healthy mangroves mean critical protection for almost a tenth of its population.

Despite being a less densely populated region overall, the mangroves in the Caribbean still provide significant protection, especially for buildings and infrastructure. On the southern U.S. coast alone, the value of built stock protected by mangroves ranges from 11.3 billion US$ in average annual storms to over 75 billion US$ in the case of strongest storm scenarios.

In a century storm scenario, the value of U.S. infrastructure protected by mangroves alone would be equivalent to more than 5% of Florida’s entire GDP.

Cuba and the Bahamas, two large islands, benefit from protecting the mangrove forests lining most of their long, intricate coastlines.

However, in addition to protecting human lives and infrastructure on the coasts, mangroves provide a range of ecosystem services.

In Lammert Hilarides’ words, “Mangroves’ exceptional ability to store and trap organic carbon in their soil, build coastal resilience, and supply livelihoods for millions of people, while being a cradle of biodiversity, makes them the ultimate forest ecosystem nature-based solution to climate change.”

According to the Global Mangrove Alliance, mangroves soak up 218 million tonnes of CO2 — as much as 47 million cars are produced annually. In this grand scheme, it is hard to overstate the importance of mangroves in relation to our climate goals.

Indonesia’s mangrove forests store over a quarter of the all-blue carbon captured by the world’s ocean and coastal ecosystems.

When comparing mangrove conservation versus interventions such as reducing terrestrial deforestation, reforestation, and peatland degradation, it becomes clear that in the vast majority of Southeast Asian and Caribbean countries, non-mangrove nature-based means for carbon capture only tiny fractions of the potential that mangrove loss reduction and restoration hold.

Peatlands, another significant carbon sink, sometimes host mangroves, especially in Southeast Asia. We can observe the opposite phenomenon in East Africa: peatlands are often found within coastal mangrove areas. So while East Africa’s mangroves’ overall blue carbon potential is smaller than that of Southeast Asia or the Caribbean, their per ha emission mitigation potential is high and protecting their habitats directly translates to protecting peatlands. Therefore, mangrove and peatland conservation in many areas will deliver a win-win for carbon sequestration.

Mangroves as an avenue to reach Mozambique’s Nationally Determined Contribution requirements: the East African nation has committed to mitigate 40 Mt of CO2 emissions in their NDC commitment with mangroves providing a restoration potential of about 4.75 MtCO2eq (1.1 aboveground biomass, 3.6 soil organic carbon). In other words, mangroves alone could deliver more than 10% of Mozambique’s NDC commitments.

Investments in mangroves can boost local economies, protect societies, and bring us closer to realizing our climate goals

Thanks to their carbon sequestration and biodiversity benefits, mangroves provide excellent avenues to support our climate goals. They also strengthen local and national economies by providing fishing grounds and serving as coastal barriers, preventing erosion and protecting infrastructure and human lives.

In Southeast Asia, increased protections for coastal areas could lead to a better balance of fishing pressure and coastal population protection against floods. GMW data demonstrates that the region’s vast extent with little protection should be one of the main focus areas for expanding mangrove protections.

In Eastern Africa, more selective, careful, and sustainable practices in urban development, agriculture, and energy sourcing could greatly bolster countries’ NDC CO2 sequestration and food security potential, which mangroves provide.

In the Caribbean, mangroves lost due to storms and urbanization must be restored and expanded to protect people and new infrastructure against extreme storm events.

Governments and conservation agencies need to act to conserve and restore mangroves. GMW provides updated data and tools to assess the potential of mangroves’ environmental, social, and economic benefits. Through GMW, governments and conservation managers can understand the benefits and monetary value of protecting and restoring mangrove habitats in individual countries, regions, and localities worldwide. GMW’s analysis also demonstrates that mangrove protection and conservation greatly outweigh any costs or profits from destructive activities in or near mangrove ecosystems.

“Securing the future of mangroves requires all hands on deck, including investment and government support to move from small- to large-scale mangrove conservation and restoration initiatives using expert guidance combined with local support,” as Hilarides puts it. “For policymakers, researchers, conservationists, and land managers, the Global Mangrove Watch should be the first point of entry for understanding the state of mangroves across our planet. GMW is the combined effort of space agencies, scientific institutions, companies, NGOs, and local partners. While space may be the final frontier, it recognises that our planet is still our only home. Mangroves play a significant role in ensuring the longevity of life on Earth.”

Explore the Global Mangrove Watch platform here. If you are part of an initiative that needs the support of action-ready data or mapping tools, reach out to us at hello@vizzuality.com.

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This blog is a collaboration between Angel Arcones, Senior Scientist at Vizzuality, Alexander Wowra, Sustainability Communication Specialist (for Vizzuality at the time of writing), and Arin de Hoog, Senior Communications Specialist at Stand.earth (at Wetlands International at the time of writing).