Mangrove forests: the muddy mazes that stash carbon and hide secrets

This post is also available in: Español

For a virtual journey through the Philippines’ mangrove forests led by Michael Du and Camille Rivera, join the GLF Bonn 2020 digital conference on 4 June.

This story is part of the Landscape News series Forgotten Forests.

In Gabriel García Márquez’s landmark 1967 novel One Hundred Years of Solitude, a character who loses touch with reality is described as disappearing into “the mangrove-swamp of delirium.” The metaphor was likely an obvious one for Márquez, who grew up amongst mangroves in the remote Colombian town of Aracataca and knew well the feeling of being ensconced in those forests’ braided, muddy tangles.

Partly due to their mysterious, inaccessible nature, mangrove forests across the globe have historically been undervalued and treated as wastelands – areas ripe for high-impact development, such logging or tourism, or transformed into highly-pollutive aquaculture enterprises such as shrimp farms. When Daniel Murdiyarso, a principal scientist and mangrove specialist at the Center for International Forestry Research (CIFOR), first trained as an ecologist, he recalls that, “we were taught that mangrove forests were ‘marginal land.’ So they have been marginalized for many, many years now.” 

In the Sanquianga region on Colombia’s sparsely-populated Pacific coast, this disdain for mangroves has historically extended to those who make use of them: the women – mostly Indigenous and Afro-Colombian – who harvest piangua [Anadara tuberculosa], a small black clam that lives in mangrove mud.

Piangua is a staple food and cultural keystone in the region: locals “have hundreds of ways to cook it,” says Óscar Guevara, a senior specialist in climate change adaptation at World Wildlife Fund (WWF) Colombia. “It’s almost in every meal every day.” 

Nevertheless, the women who harvest them, the piangueras, are often stigmatized for their work, despite playing a critical role in providing the wider community with nutritious, inexpensive and culturally-important food.

In the same way, marginalized mangrove forests across the globe are quietly performing crucial ecosystem services that impact the climate and livelihoods for the better. The trees’ twisted, labyrinthine root structures provide nurseries for multitudes of fish species, and the forests host far more biodiversity than initially meets the eye. Sanquianga’s mangrove forests, for instance, are home to 11 different kinds of mangrove; intriguing creatures like spectacled caimans [Caiman crocodilus], white-lipped peccaries [Tayassu pecari] and crab-eating raccoons [Procyon cancrivorus]; numerous bivalve species; and a vast range of epiphytes and climber plants, among many other forms of life. 

The slimy, salty mud that mangroves steep in is important, too. The trees trap sediment from freshwater flows, which keeps seawater clear and creates a barrier between the land and the ocean – a key feature as climate change causes oceans to rise and extreme weather patterns to buffet coastlines across the globe.

“Mangroves help a lot with climate-change adaptation,” says Murdiyarso, “because when you plant them, sedimentation takes place very quickly, which means the land is built up rapidly – and the hinterland is protected from sea-level rise.”

That notorious mangrove-mud also helps with climate-change mitigation. The forests punch well above their weight in terms of carbon sequestration, storing more carbon per unit area than any other ecosystem on Earth. Mangroves can stash away up to 10 times the carbon of terrestrial forests, primarily through storing it in soil.

And yet, we’re quickly losing these largely-forgotten forests. At least 35 percent of the world’s mangroves were lost between 1980 and 2000, and they’re currently disappearing by about 1 to 2 percent per year. “It feels like we’re just running, running, running before it’s all gone, trying to understand and protect what’s left,” says Murdiyarso.

Back on the Colombian coastline, local communities are collaborating with the government and civil society to ensure that their precious forest is preserved and restored for generations to come. The mangroves there, which stretch over 2,927 square kilometers (1,130 square miles) and feature trees rising to heights over 40 meters (130 feet), sit on a mix of national park and private land – most of which is communally-owned by local lndigenous people. 

Because of the low population density in the area, says Guevara, the forest is one of the most well-preserved of its type in the world. But in recent years, some locals and outsiders have begun clearing sections of forest to grow illegal coca crops and using the dense, winding waterways to store and transport cocaine, while others have started clearing land for mining.  

This has been an impetus for the WWF to place a strong focus on governance and education in its work in the region. “The challenge of doing more conservation and sustainable management here is all about empowering the local community,” says Guevara.

This includes, among other things, helping piangueras become more involved in decision-making about the environments in which they work, and educating the community’s children about the value of the mangroves and the restoration process.

The organizations are also laying foundations for future employment through nature-based tourism in the region, which has been done admirably in other parts of Colombia: back in Márquez’s stomping ground on the Caribbean coast, for instance, local young people are employed as guides for literary-and-ecological boat tours of the mangrove forests he called home. 

Across the Pacific, in the Siaton region of the Filipino island of Negros, mangrove tourism is also taking off. Videographers Justin Davey and Michael Du filmed their experience there in 2019, where they were guided by Camille Rivera, the community engagement lead for local non-profit Marine Conservation Philippines.

“We didn’t have to walk through much mud, because they’ve built this beautiful boardwalk there to give tours to people, so it was really the best of both worlds,” says Du. “It was definitely very humid, lots of insects buzzing around.”  Du hopes that engaged, well-connected and youth-friendly organizations like Rivera’s will continue to inspire more tourists to visit – and more young people to seek sustainable livelihoods in and around these important ecosystems. 

Making some mangrove forests more accessible and palatable to the public could certainly help to boost their profile. But for Murdiyarso, the forests’ wild other-worldliness is actually part of their appeal. “Lots of people don’t like to work there; it’s not exactly a nice place to work, because of the muddy smell and the mosquitoes,” he says. “But the vegetation in these ecosystems is unique and charismatic. In this very saline environment, often up against wild weather patterns, they survive. There’s definitely something special about that.”