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Central American University - UCA  
  Number 157 | Agosto 1994
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Nicaragua

Mangrove Swamps: the Sea's Kindergarten

The mangroves are the childhood gardens of the seas. The waters there are a nutritious soup that feeds a great number of child-species. The shrimp business should not signal the death of the mangroves.

Raquel Fernández

They get a lot of bad press they're not good for much except breeding mosquitoes and thus, malaria and other illnesses. But the truth is that mangrove swamps are the kindergarten of the seas, a protected place for young marine life.

A mangrove swamp is a practical lesson in tolerance and pluralism, an ecosystem in which realities so different as to appear irreconcilable like earth and water, fresh and salt water all come together to dialogue, to help each other out and to fertilize. The few vegetable species that have been able to adapt to the hostile, highly saline environment of the mangrove swamp offer a home to innumerable animal, primarily aquatic, species. The result is a teeming abundance of life, a place where many species from land, water, air and the trees all find their home during times that are key to their development.

A Fragile and Special Ecosystem

Mangrove swamps can be found all along the protected tropical and subtropical coasts of the world, particularly at the mouths of rivers. A very special kind of vegetation develops in these areas. It must survive in a highly saline environment, even though there are also large amounts of fresh water. Such vegetation must be able to grow in soil that is always moist and muddy, oftentimes underwater a number of hours each day, or for months of the year.

The mangrove ecosystem is extremely fragile. It is very easy to break the balance reached by life, the brackish water and all the various other factors that come together in exuberant harmony to maintain development in its territory. This becomes even more true when there is significant human pressure on these systems.
On both the Atlantic and Pacific coasts of Nicaragua, ocean and fresh water frequently mix in the correct proportion to produce the rich miracle we know as the mangrove swamp. But in the populated Pacific coast area, the mangroves still remaining are a mere shadow of the vast swamps seen in the past. Pollution, indiscriminate deforestation and the belief that the best thing to do with mangrove swamps is dry them out to make them into something more "productive" has perhaps led to the definitive end of huge areas of this natural treasure.

Crisis in Cotton, Crisis in Mangroves

One of the most extensive mangrove regions conserved along Nicaragua's Pacific Coast is found in the Royal Estuary, which empties into the Gulf of Fonseca in the northern part of the department of Chinandega, very near the Honduras border.

Chinandega's ecological, economic and social history is complex. For many years, the department was one huge garden, where farmers with practical, if not theoretically understood, criteria of sustainability grew a diversified range of products. Until cotton fever hit.

The big cotton growers in the region displaced the forests of fruit trees that had offered such rich shade to Chinandega's soil. They also displaced part of the peasant population, which was relocated in Nueva Guinea, an unsettled region in the southern central part of Nicaragua. The excuse used by the politicians was that it was to save the peasants' lives, since the Consiguina volcano had just erupted rather spectacularly. But the real reason was to promote cotton cultivation.

Cotton was an ecological catastrophe for Chinandega as a whole, but it did not affect the mangroves swamps. Most of the population who stayed in the area found jobs on the big cotton plantations, leaving the mangroves to grow in peace.

As the years went by, however, cotton prices began to fall on the world market and growers started losing interest in the crop. That's when the trouble began. The crisis in cotton production led to a parallel crisis for the mangrove swamps. Masses of jobless people spread out over the swamps seeking, in the cutting of firewood, a way to ensure their economic survival. More destruction has been done to the mangroves in the current government's four years in office marked by massive unemployment, particularly in the northwestern departments of León and Chinandega than in the last 40 years combined.
Today, firewood peddlers are finally beginning to realize that if the swamps are wiped out, the only way of life left to them will be gone as well. So they have begun to organize to protect the mangroves from both themselves and others. Because the poor on the coast are not the only ones interested in these swamps. The rich back in the city dream of transforming them into vast shrimp farms. And it is from them that the mangroves really must be most jealously protected, because the destructive capacity of one rich man wielding a huge Caterpillar is far greater than that of a hundred poor people armed with machetes.

A Mere Handful of Hardy Adapters

Nicaragua's mangrove swamps have their own characteristics, which differ between the two coastlines. On the Atlantic, a tree popularly known as the red mangrove or, simply, mangrove is virtually the only vegetation. It belongs to the Rhiphoraceae family and its botanical name is Rhizophone mangle. Although this species is also found in abundance along the Pacific coast, the evolution of these areas has been more complex so other species also adapted to salt water are found there in abundance.

"The red mangrove is a pioneer," says botanist Alfredo Grijalva, head of the Central American University's herbarium in Managua. "It is the vegetable species found nearest to salt water, where no others are able to survive. From there, it moves out to colonize other territory, retaining sediments to create a soil where, subsequently, other vegetable species can take root and prosper."
It is to this bold red mangrove that the ecosystem owes its most interesting characteristics: its mobility, its tendency to grow, its ability to convert itself into a dike that holds its own against the sea's crashing waves.

Another tree, the angelín, is found in the second, more inland strata, on somewhat more solid ground that does not necessarily flood with every tide. This tree, whose botanical name is Laguncularia racemosa, is also found in the Atlantic coast mangrove swamps.

Two other species are found in the third strata: the white curumo, or salt tree (Avicennia germinans), and the black curumo (Avicennia bicolor). A fourth vegetable species, which establishes a border between the flood plains and those considered terra firma, is the buttonwood (Conocarpus erectus).

That's about it. Fewer than 10 vegetable species in the Pacific mangrove swamps, which are richer and more varied than the ones in the Atlantic.

The Mangrove Tree: A Marvelous Adapter

Mangrove trees have adapted to their difficult medium in multiple ways. A system of roots extended outward and down like inverted umbrella spokes at different levels up their trunks prevent the sea from uprooting them from the soft, muddy soil. The interlaced roots of neighboring trees make up a vegetable network that holds the soil in place and ensures that each tree helps the other fend off the ravages of the sea. To facilitate oxygenization, respiration and improved gaseous interchange, these roots have small exposed rhizomes that peek out from the muddy soil like so many small fingers.

The soil where the mangroves grow is like a muddy sponge, which gives way to any weight, opening up then closing around the foot of anyone trying to walk on it. And it oozes water: as one's extended foot sinks down into the porous mud, the water level rises in the hole where the other foot is already sunk. Those who walk among the mangroves as part of their work warn that one should stay close to the trees' roots, because that's where the soil is most compact. But there's no danger that the adventurous walker will end up trapped in the mud. It is not like the deadly quicksand traps. It's more like nature is having a bit of fun, playing at not letting anyone who dares venture into mangrove territory move forward or get back out easily.

Thanks to the work of the mangroves, this gelatinous soil continues to consolidate and to encroach, little by litter, on the sea, creating new habitats and expanding existing ones, to the benefit of humans who will one day populate these soils, by then dried and desalinated.

Mangrove trees, which can grow more than 60 feet tall, are viviparous. They don't risk letting their seeds fall on vulnerable soil where the tides could take them out to high sea and ruin any chance at germination. The seeds grow in the tree's branches until they form what the peasants call "the little candle", known to scientists as rhizophores. This little candle is a masterful work of that brilliant engineer, nature. The heavy and light elements that form it are distributed in such a way that when, once mature, it falls into the mud, it is planted. It only has to begin to put down roots. Put another way, mangroves are born on their feet.

The Red Mangrove's Treasures

The whole mangrove is a treasure; everything can be well used. This is particularly true with the red mangrove, whose wood is excellent for cooking and can also be used to make vegetable based charcoal.

For many years, firewood from mangrove trees was in relatively small demand. It was only used by families living near the swamps and by some professional firewood gatherers who cut it to sell in the city. In those days, the firewood gatherers had a very wasteful custom, particularly since the red mangrove does not sprout again when cut down, it dies. They cut the tree down just above the top ring of exposed roots, using only the best part of the trunk, and leaving the many broad roots to nature. But those roots are very good for making charcoal and can also be put to good use in construction.

For many years, the young red mangrove saplings were used as cradles to support the banana trees in the region's huge plantations. This practice, which can be considered a veritable arboricide of the young plants for repopulation, was prohibited in the 1980s and is no longer used.

Until it was replaced by chemical substitutes, tannin extracted from the red mangrove's bark was long used to cure and tan leather. Stripping the bark off of trees for so many years without thinking twice it has left the mangrove swamps full of white skeletons that rise up from the mud and water like ghosts.

When the growing need for firewood and jobs legalized the cutting of these skeletons, it was found that the barkless trees had become so hard that it was virtually impossible to cut them with a machete or ax. Thus, the use of chainsaws was authorized essentially decreeing the death of the mangrove swamp.

The red mangrove has the best wood, but is also the weakest species in evolutionary terms. It is the most fragile, the easiest to kill and the hardest to reproduce. And with the red mangrove goes the whole swamp. When these trees are cut down in blocks, their space is quickly filled by other species, which leave no room for the mangrove to reproduce. The other species don't have the ability to create new territory and, as with so many other things, those who do not advance are forced to retreat.

People of the Ñanga

Nobody lives in a mangrove swamp. Its spongy soil and intermittent flooding linked to the movement of the tides make it uninhabitable for human beings. But many people live off the mangrove swamp, which they call not by its formal masculine name in Spanish manglar but by the feminine ñanga. It's the same as with sailors, who speak of the sea as feminine, never masculine. The people of the ñanga go in and out of it, just as if it were a job, making a living off of the swamp's most visible products. There are also so many other, not so visible, by products that all of us, to one extent or another, live off the mangroves. In this sense, we are all people of the ñanga.

Beginning a number of years ago, the Danish Development Authority (DANIDA) has been advising people who live off the ñanga, teaching them how to keep this ecosystem their environment and livelihood both alive and vigorous. The DANIDA MANGROVE project identifies those trees that not only can be cut, but should be cut. Among them are those attacked by termites, which destroy the trunk from the inside, leaving it hollow, and those too old and tall, which damage the growth of other trees by not letting through sufficient sunlight.

To facilitate its work with the firewood cutters, the project helps them organize into cooperatives where they receive technical training on how to properly manage the trees. They learn how to recognize a sick tree and a healthy one, which ones to cut and how to cut them, and how to make the best possible use of each cutting.

José Hernández is part of a firewood cutters' cooperative that works according to the DANIDA MANGROVE orientations. In his case, one cannot say, as in stories, "Every morning, José Hernández takes his ax and marches off to the forest to cut firewood..." Because in the ñanga, the sea and its tides, not a clock or the sun, marks the time.

To go deep into the ñanga, Juan and his partners have to wait for high tide, then paddle their long dugout canoes through the estuary's labyrinth of water and mangrove branches until finding the trees that are to be cut. Then they wait for low tide to begin work. Cutting the trees and hauling them onto the canoe must be done at low tide, and one sinks constantly into the mud. When enough trees have been cut, there's another wait for the tide to rise again so they can return to the sawmill, where the huge trunks are pared down to marketable size.

This whole process requires several tides. The tree fellers take advantage of high tide to sleep, whatever hour that happens to be, and work at low tide. After three or four days of this, they are ready to go back out of the ñanga, leaving behind clouds of mosquitoes and many other dangers. It is a backbreaking and poorly paid way to make a living. Walking through the mangroves without having to hold anything, or do any work, is hard enough. What must it be like to try and cut wood under these conditions? In any case, the work keeps people eating every day, and, in today's neoliberal Nicaragua, that's more than some people do.

José Hernández holds that neither he nor any of the 19 other cooperative members cut healthy trees. "It's not in our interest, because if we cut all the trees, we'll have nothing left later." All the firewood cut by José and the others, which is now filling an enormous tractor trailer, has one thing in common: it has been eaten away by termites.

"Before, yes," he confesses, "we destroyed everything. Any tree was good enough for us. But now we're more careful. We're aware of what's going on now. The project has explained things to us, they've given us workshops. So now we only cut sick trees."

Sea Life Nursery

The roots of the mangrove trees form a kind of network in which only very small species or the offspring of large species can live and move around. Mangrove trees constantly drop their old leaves and produce other new ones this mass of vegetation falls into the stagnant, brackish water and rots there, undisturbed. The water rises and falls, but there are no waves. There would have to be a huge storm at sea for the water in the interior part of the mangroves to even ripple, because the trees closer to the sea act as a buffer.

For all these reasons, mangrove swamps are a magnificent place for many kinds of insects to lay their eggs. In fact, one of the worst charges made against the mangroves is that they end up being a mammoth hatchery of insects, many of which are a danger to human health. But the eggs and larvae of the insects are good feed for many aquatic species. The swamp water is like a highly nutritious soup for the marine species that live there in key stages of their infancy, when they most need to eat. The tangled roots also form a safe place: the infants of the species can eat abundantly with no risk of being eaten. The mangrove is thus the nursery, as it were, of the seas. For all practical purposes, the majority of the marine species, marketable or not, depend on the mangrove during some important stage of their life. Among such species are anchovies, groupers and catfish. And, of course, shrimp.

Harnessing the Shrimp Cycle

Shrimp have a very short life cycle they live scarcely a year and a half. During that time, they travel a long circular route from the high sea to the mangroves, where they live for some time, before returning to the ocean for mating. Each female lays between 500 and 1,000 eggs, already fertilized, and entrusts them to the sea. The tides drag the eggs away and when some 20 22 days have gone by, those that, with luck, have hatched into larvae and made it to the estuaries start searching for the most intricate places of the mangrove coves. Before getting there, the larvae are fairly autonomous and can feed off the microscopic algae phytoplankton and the tiny sea animals known as zooplankton.

In the estuary, the shrimp live for three months, which we can consider their infancy and adolescence. During this time they feed well enough to return at maturity to the sea. where they will live out their lives.

Shrimp farming uses this cycle for commercial ends. The larvae are captured in the estuaries and coves and taken to special tanks for fattening. But greed makes human beings myopic. To exploit shrimp farming to the maximum and reduce the costs of exploitation to a minimum, some people have destroyed large areas of mangroves to build the tanks. Shrimp farming, which depends directly on the mangroves, actually wipes them out in the search for a few quick dollars.

The pools can feasibly be installed in the salt flats immediately behind the mangroves, which are unable to produce anything. It means making the input channels and water piping a little longer, but anyone able to invest a million dollars in "planting" 100 hectares of shrimp the minimum invested by the large shrimp companies could just as easily spend a little more to maintain the mangroves, on which shrimp and dozens of other species depend. Scientific data show that more life is produced in the mangrove swamps than in all the world's ponds put together.

What happens is that many of those who "buy" a few acres of mangrove land feel as if they own it and thus have the right to do to what they like with the ecosystem. And the first thing that occurs to many is to cut the trees and dry the land ostensibly for health reasons. The devastating effects then suffered with the loss of this space and life are felt first by fishermen, whose catch at high sea is drastically reduced. It also happens that those who buy a mangrove swamp, if they want banking credit to make it productive, must make "improvements" in order to get that credit. According to some off base banking criteria, the first "improvement" demanded on land with trees, whether mangroves or not, is to chop those trees down. Only then does the loan money start to flow.

Emancipated Women in the Mangroves

Nicaragua's Pacific coast mangrove swamps are also the stage for a reality that wasn't exactly on the agenda: women's struggle for their emancipation.
It all began in 1987, when 35 women organized themselves into the "Lucrecia Lindo" cooperative to take up shrimp farming. From the beginning, these women saw respect for nature as important so they decided to install the fattening tank in the salt flats behind the mangroves.
Building those installations meant very hard work over a long period of time. But the greatest obstacle was not the work; it was their husbands and women who were not part of the project. Zoila González, a founder of that cooperative who will stay in it at any cost, has many bitter memories. "Since we had to go out to work when it was still dark, we'd go around to the women's houses to wake each other up, because if we didn't, many would stay fast asleep. And people from the village said, 'Oh, there go those a curse word here horny women. Where are they going, leaving their homes when it's not even light yet, if not for that? A woman should be in her home, she's got no business being out on the streets, particularly at night.' And it went on like that day after day."
Some men forced their wives to choose between them and the cooperative; most of those women resigned from the cooperative. Others, though they had courage to spare, lacked the physical strength to take on such hard work. There are currently 16 women in the cooperative, owners of their own lives and their futures. They speak confidently with bankers, discussing their criteria, and not letting a thing get by.

Nothing goes by them. In fact, they have even begun another project raising iguanas, a species natural to the mangroves and one rapidly being decimated. The iguana has tender, flavorful meat, like chicken, and its eggs are prized as well and fetch a good price. The cooperative's iguana farm has three objectives: sell the meat and eggs; sell the docile, affectionate, easy to care for iguanas as pets; and send baby iguanas back out into the mangroves to repopulate.

Since the women of the "Lucrecia Lindo" cooperative all have a number of children, they are not satisfied with this income. So they are also planting fruit trees and vegetables next to the ponds, to diversify their family diet. DANIDA MANGROVE workers provide technical assistance through training courses.

The evident success scored by these women has led to the organization of four other all women cooperatives in the area. And the men, who constantly predicted disaster for those daring to defy established order, no longer dare say a word. In fact, a number of men who abandoned founding members of the "Lucrecia Lindo" cooperative to go off with other, less determined women, now watch as they, too, join a similar cooperative. Reality has left these men without a single argument.

Lots Still to Learn about Mangroves

Very little is known about mangroves, and the few studies done come primarily from Southeast Asia, so are not necessarily pertinent to the Nicaraguan coasts. Applying the existing knowledge to the country's reality is difficult.

For the last two years, the DANIDA MANGROVE project has been doing ongoing research on mangroves in the Royal Estuary, so that the knowledge gathered there can be applied to other areas in the country. Biologists Chester Conrado and Leonel Martínez and ecologist Silvia Palacios make up a team coordinated by engineer Ninoska Hurtado that is currently doing research indispensable to initiating scientific management of Nicaragua's mangroves.

"I'm not a big supporter of the romantic forest, or the romantic mangrove," says botanist Alfredo Grijalva. "I think they should be used to our benefit, but with certain criteria. We must understand what we're doing, and take care of our resources so they are renewed and will serve coming generations as well."
It is still unclear how long mangrove trees take to grow, how much time is needed to replenish them or how to restore them to areas where they have already disappeared. It is known that, where mangrove swamps still exist, they defend the coastline from damage by the sea. The mangrove trees' dense crowns break up the first blow from a tidal wave. The water still travels on to the more populated zones, but in a tamed, inoffensive form. In the United States, where vast extensions of mangroves have disappeared, enormous and very costly dikes have had to be constructed. And they don't always do their job as well as the mangrove, which was there for the asking.

Mangrove swamps have historically been "damned" areas, and the people living near them stereotyped as suspicious. Hollywood has done mangroves a disservice, portraying them only as the spooky hideout of villains, or the backdrop for a hair raising speedboat chase. They are clearly much more complex as is everything that is close to life itself.

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