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Mangroves

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Swampy mangrove forests have long been seen as a nuisance—nothing but mud and mosquitoes—and have been eagerly cleared. But in fact, mangrove forests are critically important ecosystems. And now, in the face of the global climate emergency, they have never been more important.

Mangroves are shrubby trees that grow along the shorelines of tropical and subtropical regions. Unlike most plants, they thrive in brackish water. The unique stilt-like roots of these resilient trees are anchored in sediment but extend above the water’s surface. These underappreciated ecosystems provide myriad environmental and economic benefits:

Habitat for fish and other creatures. Many juvenile fish live among the mangrove roots, safe from predators, until they are big enough to head out to the reef or ocean. So if there are no mangroves, there are many fewer reef fish. This can be devastating to reef ecosystems and the millions of people who depend on them for food security and livelihood.

Better water quality. Mangroves trap sediment, making for clearer water. They also absorb excess nutrients from runoff that can cause algal blooms, which deplete the oxygen in the water.

Fewer lives lost during natural disasters. Mangrove forests provide an effective buffer against waves and wind. When tsunamis or cyclones or increasingly violent cyclones hit, communities sheltered by intact mangrove forests suffer fewer deaths and less damage than those without them.

Carbon sequestration. Mangrove ecosystems trap many times more carbon than other terrestrial ecosystems, playing a key role in keeping carbon dioxide out of the atmosphere and helping to mitigate climate change. The key is that vegetation decays very slowly because it is underwater, so little carbon is released. But if mangrove forests are disturbed, they release a tremendous amount of CO2.

The Threats to Mangroves

People who live near mangroves have always used the forests as a source of building materials, fuel, and fish. On a small scale, these practices are sustainable. But more intensive use spells disaster.

Mangroves’ ability to flourish along tropical coastlines makes them vulnerable, because many coastal areas are popular places for agriculture, homes, or tourism. In the past 100 years, it’s estimated that the global mangrove population has been cut in half. The problem is especially acute in Southeast Asia. It took just 20 years for half of Myanmar’s mangroves to disappear, according to a study published in 2020.

Sometimes marshy land is drained and filled, so people can build houses or hotels. Sometimes mangrove trees are ripped out so the land can be used for crops or aquaculture. Fish and shrimp ponds are especially destructive. Bulldozers tear out the trees and push mud around to make enclosed areas. After just a few years, there is so much pesticide, concentrated fish waste, and fish food in the water that it’s no longer usable. People abandon the fish farms and move on, leaving the hydrology greatly changed, the water poisoned, and plastic netting tangled in the mud. It’s not easy to bring back a productive mangrove forest.

Giving Mangroves Their Due

Many organizations and governments now realize that mangroves are key to healthy environments and economies. They are seeking to increase protection for these amazing and valuable ecosystems in several different ways.

Education and Outreach

Mangrove forests, often pegged as smelly, swampy, and buggy, have an image problem. To encourage conservation, people need to appreciate them for what they are: a constantly changing tidal ecosystems, teeming with birds and other wildlife, and essential to planetary health.

That’s where public education programs, sometimes called pride campaigns, come in. The Mangrove Action Project, for example, has developed a “marvelous mangrove” curriculum for schools. It’s hands-on, science-based program that educates teachers, so they can share the knowledge with their students. Seacology has also funded many local education programs focusing on mangroves. We’ve found that children are the best educators—of their parents!

Ecotourism

Another way to foster appreciation for complex mangrove ecosystems is to get people out in a mangrove forest, so they can experience its beauty for themselves. Strolling on a boardwalk or paddling a kayak through still waters, they can spot exotic birds and enjoy the sunlight as it filters through the leaves.

Seacology is partnering with communities in several countries on projects to promote true ecotourism—that is, tourism that benefits local people and promotes conservation of the natural world. For example, in the Dominican Republic, Seacology has funded improvements to tour boats that take visitors out to see flocks of flamingos and other birds in Oviedo Lagoon, part of Jaragua National Park. We have also worked with partners to make boardwalks with interpretive materials a success in mangrove areas from Peru to the Philippines.

Protection and Replanting

Many island communities know very well that their physical safety and their livelihoods depend on healthy mangrove forests. They are often enthusiastic about restoring mangroves that have been lost. We have supported many efforts, from replanting in Grenada in the Caribbean to reclamation in India. These projects are most successful when they rely on sound scientific advice: which species to plant, where and when to plant them, and how to monitor the results.

Our most significant mangrove conservation and reforestation project is in Sri Lanka, the island nation off the southeast cost of India. We worked with the Sri Lankan organization Sudeesa and the national government to protect all of the country’s mangroves. This five-year undertaking conserved thousands of acres of mangrove forest. It also brought economic opportunity, in the form of microloans and business training, to impoverished Sri Lankan women. The United Nations awarded Seacology a Momentum for Change award in recognition of the project’s role in fighting global climate change.