Mangroves: the Roots of the Sea

Synopsis

There aren't too many happy stories when it comes to restoring damaged ecosystems, but people in southern Thailand's Trang Province tell one of them, thanks to an innovative grassroots organization called Yad Fon. Founded in 1984, Yad Fon set out to rehabilitate the mangrove ecosystems that had sustained families in the area for thousands of years. How? By helping villagers manage their own natural resources.

In the Hands of the Fishers: The Yad Fon Story

Thanks to an innovative grassroots organization called Yad Fon, southern Thailand's Trang Province is home to an inspiring example of ecosystem restoration.

Failing Forests, Dimming Futures

Not long ago, Thailand's Andaman coast was lined with mangroves, the extraordinary trees and shrubs that dominate tropical shorelines because of their unique ability to thrive at the edge of the sea. The local people fished these productive wetlands with traditional hand nets, catching enough fish and crabs to support their families. The seafood stocks replenished themselves. The system was sustainable.

But starting in the early 1970s, a booming shrimp farming industry began bulldozing mangrove forests to make way for artificial ponds, which produce waste that pollutes the land and water. Big trawlers began fishing within the legal three-kilometer limit with push nets. These nets scrape the ocean bottom, doing great damage, especially when used near the shore. As catches dwindled, the villagers themselves began to scramble for what was left, resorting to cyanide poisoning and dynamite to kill or stun fish, and to their own version of push-net fishing. Coastal communities struggled or collapsed as fishermen could no longer support their families. Some villagers began cutting down mangroves for the local charcoal industry, while others migrated to an uncertain future in urban areas.

Yad Fon Steps In

In 1985 a small nonprofit organization called Yad Fon ("raindrop" in Thai) was founded in Trang, in southwestern Thailand. Targeting the very poorest villages in the area, Yad Fon set out to restore the healthy mangrove ecosystems that had sustained families for thousands of years by encouraging the villagers to manage their own natural resources. Yad Fon's motto, "In the hands of the fishers," reflects their goal: self-sufficient rural populations whose livelihoods and traditional cultures are ensured.

The obstacles were formidable. Decades of focus on economic development in Thailand had fostered a culture that tolerated environmental crimes like illegal logging, poaching, illegal fishing, and industrial dumping. Environmental laws are poorly enforced, and corruption is rampant. A credit-based wholesale fish distribution network made it impossible for fishermen to negotiate fair prices for their catch and difficult for them to get out of debt. Few villagers had legal title to land they had worked for generations. Convincing people to question authority—especially illiterate villagers confronting powerful industrial and government interests—was difficult in a hierarchical culture like Thailand's, where people tend to avoid conflict.

The First Step: Learning From Each Other

Yad Fon began with four villages. Yad Fon staff members lived in each village for extended periods, building the relationships that grassroots organizing depends on, and learning about the problems each community faced. Next, they proposed small-scale projects that everyone agreed would be of benefit, such as building a community well. Leaders came forward, local skills were tapped, and villagers began to work together to apply a combination of local wisdom and modern knowledge to solve common problems.

Dealing Some Economic Cards

Yad Fon also undertook some fiscal programs to give the villagers some breathing room. They set up a group savings program that loaned people small amounts of money at low interest and provided a kind of collective insurance against hard times. A "revolving fund" offered small interest-free loans to the extremely poor, helping them extricate themselves from a spiral towards bankruptcy. A cooperative buying program enabled fishers to purchase supplies like diesel, netting, lines, and tackle at reduced rates. And collective bargaining allowed fishermen to receive fair market prices for their catch, thus bypassing unfavorable pricing structures of middlemen.

AMNH

Learning to Think Collectively

One of the cornerstones of Yad Fon's work is the creation of "community forests": mangrove stands that are managed communally by a village or group of villages. The community forests act as buffers against hard times and safeguard the future of villagers who depend on forest resources. Members agree on rules for using the forest. For example, in one community forest, members are allowed to cut trees for lumber and fuel in one area as long as they replant accordingly; another area is designated for the harvest of medicinal plants and herbs; a third is for the education of schoolchildren; and a fourth area is reserved for traditional fishing and crabbing. Because everyone benefits, everyone is motivated to patrol and protect the forest. Cooperative ownership gives the villagers legal recourse against commercial exploitation, and the program set an important precedent by winning the support of the Thai Forestry Department.

Healthy Ecosystem Pay Their Way…And More

One of Yad Fon's early target villages began managing only a small stretch of mangrove forest while also replanting a degraded area. Within months, near-shore fishing improved, and within three years the total catch improved by 40 percent. As mangroves were replanted and protected, seagrasses and coral reefs regenerated. Marine species that had become rare or absent entirely, such as whale sharks, dolphins, and dugongs (relatives of the manatee), began to reappear. Fishermen spent less time in their boats, their expenses went down, and community income increased. Villagers also benefited from small-scale aquaculture projects, in which individual families reared milkfish, grouper, and mussels in floating pens just offshore. These economic payoffs strengthened the villagers' commitment to protecting their fragile land and water.

Power to the People

The success of the community forests has sharpened the villagers' sense of political empowerment. One village sent 50 fishing boats out to confront a trawler that was fishing within what they had established as a protected near-shore area and banished the intruder. When palm oil spilled into a waterway near another village, Yad Fon helped the villagers document the resulting fish kill and bring it to the attention of the provincial government. The offending corporation had to pay a fine and compensate the villagers for the loss of fishing income. In a third case, a village community forest representative confronted the owner of a nearby charcoal factory who had been sending his workers there to collect wood. The villager demanded that the violations stop and organized a work group to set up boundary markers. Because it was clear that the village leader meant business and represented a whole community, the illegal collecting ended. Again, the local government took note.

Word Spreads

Word of Yad Fon's effective organizing spread between neighbors and relatives and through gatherings in the community mosques. Before long, the Yad Fon model spread up and down the coast to include 30 villages in a network with serious clout. As villagers share successful strategies and acquire the confidence to take collective action, the coast is gaining protection from unprincipled farming and fishing operations. People have regained their self-sufficiency and learned to protect the resources their way of life depends on. The struggle is ongoing, with push netters continually tempted to trespass into the more bountiful protected areas. The future of these villagers lies in their own hands. Says Yad Fon founder Khun Pisit, “The forest sustains the people who sustain the forest.’

What's a Mangrove? And How Does It Work?

If you've ever spent time by the sea in a tropical place, you've probably noticed distinctive trees that rise from a tangle of roots wriggling out of the mud. These are mangroves—shrub and tree species that live along shores, rivers, and estuaries in the tropics and subtropics. Mangroves are remarkably tough. Most live on muddy soil, but some also grow on sand, peat, and coral rock. They live in water up to 100 times saltier than most other plants can tolerate. They thrive despite twice-daily flooding by ocean tides; even if this water were fresh, the flooding alone would drown most trees. Growing where land and water meet, mangroves bear the brunt of ocean-borne storms and hurricanes.

AMNH

There are 80 described species of mangroves, 60 of which live exclusively on coasts between the high- and low-tide lines. Mangroves once covered three-quarters of the world's tropical coastlines, with Southeast Asia hosting the greatest diversity. Only 12 species live in the Americas. Mangroves range in size from small bushes to the 60-meter giants found in Ecuador. Within a given mangrove forest, different species occupy distinct niches. Those that can handle tidal soakings grow in the open sea, in sheltered bays, and on fringe islands. Trees adapted to drier, less salty soil can be found farther from the shoreline. Some mangroves flourish along riverbanks far inland, as long as the freshwater current is met by ocean tides.

One Ingenious Plant

How do mangroves survive under such hostile conditions? A remarkable set of evolutionary adaptations makes it possible. These amazing trees and shrubs:

• cope with salt: Saltwater can kill plants, so mangroves must extract freshwater from the seawater that surrounds them. Many mangrove species survive by filtering out as much as 90 percent of the salt found in seawater as it enters their roots. Some species excrete salt through glands in their leaves. These leaves, which are covered with dried salt crystals, taste salty if you lick them. A third strategy used by some mangrove species is to concentrate salt in older leaves or bark. When the leaves drop or the bark sheds, the stored salt goes with them.
• hoard fresh water: Like desert plants, mangroves store fresh water in thick succulent leaves. A waxy coating on the leaves of some mangrove species seals in water and minimizes evaporation. Small hairs on the leaves of other species deflect wind and sunlight, which reduces water loss through the tiny openings where gases enter and exit during photosynthesis. On some mangroves species, these tiny openings are below the leaf's surface, away from the drying wind and sun.
• breathe in a variety of ways: Some mangroves grow pencil-like roots that stick up out of the dense, wet ground like snorkels. These breathing tubes, called pneumatophores, allow mangroves to cope with daily flooding by the tides. Pneumatophores take in oxygen from the air unless they're clogged or submerged for too long.

Roots That Multitask

Root systems that arch high over the water are a distinctive feature of many mangrove species. These aerial roots take several forms. Some are stilt roots that branch and loop off the trunk and lower branches. Others are wide, wavy plank roots that extend away from the trunk. Aerial roots broaden the base of the tree and, like flying buttresses on medieval cathedrals, stabilize the shallow root system in the soft, loose soil. In addition to providing structural support, aerial roots play an important part in providing oxygen for respiration. Oxygen enters a mangrove through lenticels, thousands of cell-sized breathing pores in the bark and roots. Lenticels close tightly during high tide, thus preventing mangroves from drowning.

Ready-to-Roll Seeds

The mangroves' niche between land and sea has led to unique methods of reproduction. Seed pods germinate while on the tree, so they are ready to take root when they drop. If a seed falls in the water during high tide, it can float and take root once it finds solid ground. If a sprout falls during low tide, it can quickly establish itself in the soft soil of tidal mudflats before the next tide comes in. A vigorous seed may grow up to two feet (about 0.6 m) in its first year. Roots arch from the seedling to anchor it in the mud. Some tree species form long, spear-shaped stems and roots while still attached to the parent plant. After being nourished by the parent tree for one to three years, these sprouts may break off. Some take root nearby while others fall into the water and are carried away to distant shores.

A World Traveler

Botanists believe that mangroves originated in Southeast Asia, but ocean currents have since dispersed them to India, Africa, Australia, and the Americas. As Alfredo Quarto, the head of the Mangrove Action Project, puts it, “Over the millions of years since they've been in existence, mangroves have essentially set up shop around the world.” The fruits, seeds, and seedlings of all mangrove plants can float, and they have been known to bob along for more than a year before taking root. In buoyant seawater, a seedling lies flat and floats fast. But when it approaches fresher, brackish water—ideal conditions for mangroves—the seedling turns vertical so its roots point downward. After lodging in the mud, the seedling quickly sends additional roots into the soil. Within 10 years, as those roots spread and sprout, a single seedling can give rise to an entire thicket. It's not just trees but the land itself that increases. Mud collects around the tangled mangrove roots, and shallow mudflats build up. From the journey of a single seed a rich ecosystem may be born.

Why Mangroves Matter

AMNH

Mangrove forests were once generally dismissed as swampy wastelands. Planners, scientists, and coastal dwellers have now come to value them as the remarkably diverse and important ecosystems they are. Mangroves, seagrass beds, and coral reefs work as a single system that keeps coastal zones healthy. Mangroves provide essential habitat for thousands of species. They also stabilize shorelines, preventing erosion and protecting the land — and the people who live there — from waves and storms.

Keystone of a coastal ecosystem

Mangroves, seagrass beds, and coral reefs are often found together and work in concert. The trees trap sediment and pollutants that would otherwise flow out to sea. Seagrass beds provide a further barrier to silt and mud that could smother the reefs. In return, the reefs protect the seagrass beds and mangroves from strong ocean waves. Without mangroves, this incredibly productive ecosystem would collapse.

Nursery grounds

Mangroves provide ideal breeding grounds for much of the world's fish, shrimp, crabs, and other shellfish. Many fish species, such as barracuda, tarpon, and snook, find shelter among the mangrove roots as juveniles, head out to forage in the seagrass beds as they grow, and move into the open ocean as adults. An estimated 75 percent of commercially caught fish spend some time in the mangroves or depend on food webs that can be traced back to these coastal forests.

Home to many species

Mangrove forests provide habitat for thousands of species at all levels of marine and forest food webs, from bacteria to barnacles to Bengal tigers. The trees shelter insect species, attracting birds which also take cover in the dense branches. These coastal forests are prime nesting and resting sites for hundreds of shorebirds and migratory bird species, including kingfishers, herons, and egrets. Crab-eating macaque monkeys, fishing cats, and giant monitor lizards hunt among the mangroves, along with endangered species such as olive Ridley turtles, white breasted sea eagles, tree climbing fish, proboscis monkeys, and dugongs. And the soft soil beneath mangrove roots enables burrowing species such as snails and clams to lie in wait. Other species, such as crabs and shrimp, forage in the fertile mud.

Food for the multitudes

The tons of leaves that fall from each acre of mangrove forest every year are the basis of an incredibly productive food web. As the leaves decay, they provide nutrients for invertebrates and algae. These in turn feed many small organisms, such as birds, sponges, worms, anemones, jellyfish, shrimp, and young fishes. Tides also circulate nutrients among mudflats, estuaries, and coral reefs, thus feeding species like oysters that rest on the seabed.

Clean water

Mangroves protect both the saltwater and the freshwater ecosystems they straddle. The mangroves' complex root systems filter nitrates and phosphates that rivers and streams carry to the sea. They also keep seawater from encroaching on inland waterways.

A stable coastline

Mangrove roots collect the silt and sediment that tides carry in and rivers carry out towards the sea. By holding the soil in place, the trees stabilize shorelines against erosion. Seedlings that take root on sandbars help stabilize the sandbars over time and may eventually create small islands.

Shelter from the storm

The thickets of mangroves that buttress tidal mudflats also provide a buffer zone that protects the land from wind and wave damage. Places where mangroves have been cut down for shrimp farms are far more vulnerable to destructive cyclones and tidal waves.

Resources for humans

Mangrove forests provide many of the resources upon which coastal people depend for their survival and livelihood. At low tide, people can walk across the tidal flats to collect clams, shellfish, and shrimp. At high tide, fish move in to feed among the protection of mangrove roots, turning the marshy land into rich fishing grounds. The mangrove trees themselves provide fuel, medicines, tannins, and wood for building houses and boats 

Mangrove Threats and Solutions

Straddling land and sea and teeming with life, mangrove forests are key to healthy coastal ecosystems, but it is only in the last few decades that people have begun to realize their importance. Ironically, during this same period, mangroves have disappeared with alarming speed. By some estimates, less than 50 percent of the world's mangrove forests were intact at the end of the 20th century, and half of those that remain are in poor condition. Mangrove forests are among the most threatened habitats in the world, and mangrove loss is rampant across the globe. Thailand has lost 84 percent of its mangroves, the highest rate of mangrove loss of any nation, while the Ivory Coast, Guinea-Bissau, Tanzania, Mexico, Panama, Malaysia, Myanmar, Pakistan, and the Philippines have each lost more than 60 percent of their mangrove forests. Most mangroves grow on public land, only about 1 percent of which receives any sort of protection. Even where some legal designation or protection is in place, preserving mangroves is difficult because of development in the form of: 

AMNH

Shrimp Farming

By far the greatest threat to the world's mangrove forests is the rapidly expanding shrimp aquaculture industry. Hundreds of thousands of acres of lush wetlands have been cleared to make room for artificial ponds that are densely stocked with shrimp. Shrimp farmers dig channels to supply the ponds with enormous quantities of freshwater and seawater. These water diversions alter the natural flow of water that maintains the health of surrounding mangroves as well as ecosystems farther inland and offshore. Diverting water can harm mangroves by preventing their seeds from being dispersed via seawater, and it can kill the trees by cutting off freshwater supplies. When diverted inland, seawater may contaminate farmland or freshwater below the ground. Shrimp farmers also use massive amounts of chemicals and antibiotics to keep the overcrowded shrimp healthy. This chemical soup, along with enormous quantities of organic waste, contaminate surrounding freshwater and coastal waters. In addition, the process of catching wild shrimp larvae to stock the ponds is hugely wasteful. Fishermen use nets that damage the ocean floor and trap many species besides shrimp, leaving marine habitats damaged and local fisheries depleted. The social costs of shrimp aquaculture are also high. Rather than bolster local economies, shrimp farming can actually deplete the local peoples' ability to support themselves. Because shrimp is a cash crop, not a subsistence crop, the profits from shrimp farming are exported, and the jobs it generates are usually temporary. The average Asian intensive shrimp farm survives only two to five years before pollution and disease force it to shut down. Local people are left with a devastated landscape that can no longer support fishing, farming, or wood gathering, and many are forced to move away.

Tourism

Tourism is a booming industry and an important source of income in many developing nations. Unfortunately, irresponsible tourism can destroy the very resources people are coming to see. As tourists hike, drive, or paddle into once-remote areas, they bring with them garbage, sewage, noise, fumes, lights, and other disturbances that can damage mangroves and the surrounding ecosystems. Walking off paths, lighting fires, feeding wildlife, anchoring on reefs, and collecting shells and plants are also destructive. Tourism can be sustainable when groups are small and people leave the habitat the way the found it.

Agriculture

Many thousands of acres of mangrove forest have been destroyed to make way for rice paddies, rubber trees, palm oil plantations, and other forms of agriculture. Farmers often use fertilizers and chemicals, and runoff containing these pollutants makes its way into water supplies. Despite their resilience, mangroves can tolerate only a limited amount of industrial and agricultural pollution without dying. In addition, waterways are often diverted for irrigation or paved over for roadways, which alter the natural flow of water. Because mangrove forests are adapted to tidal fluctuations, they can be destroyed by such changes to their habitats.

Coastal Development

Coastal development takes many forms, from ports and docks to hotels, golf courses, marinas, and convention halls. Everyone loves being near the sea, but as streams and wetlands are filled by roads and concrete, they can no longer process natural chemicals. Worse still, pollutants that accompany development can damage individual trees or whole tracts of mangroves. With buildings come people, traffic, garbage, and noise, each of which takes its toll on the plants and animals that inhabit rich coastal ecosystems.

Charcoal and Lumber Industries

Chopping down mangroves for charcoal and timber is an important cottage industry for many coastal communities. Mangrove wood is used for building material, fencing, and fuel. It also yields valuable, high-quality charcoal. In places where fishing has declined below subsistence levels, many people have turned to charcoal production for their livelihood, which furthers the cycle of habitat loss and fishery decline.

...

More and more people around the world are organizing to protect and restore these ecologically, biologically, and culturally diverse coastal forests. Heightened awareness of the importance of mangroves has led to projects ranging from small-scale mangrove replanting efforts to replumbing the Everglades. Communities around the world are learning how to protect mangroves and use them in sustainable ways.

Interactive: Case Studies in Mangrove Conservation

Interactive: Yad Fon Photogallery

Interactive: Mangrove Biodiversity, Close Up