Integrated aquaculture provides viable alternative to slash-and-burn agriculture, reducing destruction of tropical forests


Many nations are taking steps to protect the tropical rain forests within their borders by creating parks and nature reserves. But it is clear that this kind of action can protect merely a fraction of the world’s rain forest lands. Maintaining parks and reserves is expensive, especially for governments who are trying to meet the competing needs of other people for income and for land on which to live.

Juan Guevera’s job is to help the farmers who live in the area around the city of Pucallpa, in the part of the Amazon Basin that lies in Peru, meet their needs for food and income.


Ucuyali Basin, Peru

Problem Overview:

Destruction of rain forest, loss of genetic diversity

The earth’s climate and atmospheric conditions, its variety of soil and water conditions each supporting unique kinds of life and offering different opportunities for human habitation, all depend on a complex interaction among its different environments – deserts, forests, oceans, ice caps, grasslands, wetlands, and so on. The characteristics of any one kind of environment depend on the other environments that surround it, and even on environments hundreds and thousands of miles away.

As much as every single environment contributes in an important way to maintaining life on earth, a good case can be made for the special importance of the tropical rain forest. On average, an acre in a tropical rain forest is home to ten times as many living species as another environment. This means that the genetic material of the tropical rain forest is richer and more divers than that of any other environment, both within a given species and across the variety of species. A tropical rain forest is a reservoir of genetic diversity, and as such it is very important for humans. We are more likely to find a valuable new medicine, a new kind of food, or a new pest-resistant or disease-resistant strain of an already familiar food in a tropical rain forest than anywhere else on earth.

Tropical rain forests also play a central role in the regulation of the earth’s climate, both regionally and globally. They recycle vast amounts of carbon dioxide into oxygen, a process critical to all kinds of life and which, by removing carbon dioxide from the air, tends to cool the earth’s average temperature. They recycle rainfall into new clouds, which provide further needed rainfall not only for the rain forest itself but for agricultural regions far outside the forest’s borders. Both the cloud cover and the rain also keep temperatures cooler.

Tropical rain forests are the source of many of the world’s most important watersheds as well. The water that is not used by the plants and animals of the tropical rain forest or recycled into clouds finds its way into river systems that sustain, by providing water for irrigation, navigation, and drinking, some of the largest concentrations of people on the planet – in South and Southeast Asia, in Africa, and in South America. The levels at which the tropical rain forest releases water into its rivers, the seasonal rates at which it does so, and the nutrients with which the forest’s abundant life fills the rivers are all features of the rain forest that people who live far from the forest itself depend on for their daily survivial.

Yet, for all its value, the tropical rain forest is one of the most endangered environments on earth. People seek many things in a tropical rain forest, and two of the most widely sought pose deep risks to the forest’s survival. The first of these is wood, which is harvested and sold, usually for export. In part to save money and realize higher profits, and in part because of the very density of a tropical rain forst, such harvesting is typically carried out by bulldozers. In contrast to the selective cutting done in temperate forests, timber harvesting in tropical rain forests usually leaves a barren landscape that has no chance to regenerate itself. The second threat to the rain forest comes from attempts to convert it to agricultural uses, ranging from small single-family farms to vast cattle ranches run by multinational corporations. Because the nutrients in a tropical rain forest are held mostly in the foliage, these efforts, too, soon leave behind an empty and lifeless terrain. Topsoil in the rain forest is very thin and must be held in place by trees and other forest plants; when those are cleared away the land rapidly becomes eroded, hard and rocky, unsuitable for continued ranching or farming.

Tropical rain forests tend to be located in countries where sources of immediate income are needed, from the individual to the national levels. They are often countries with large populations, whose governments seek to open up new territories where people can get food and livelihood from farming. That desire, and the desire on the part both of private companies and of governments to realize a profit from the forest and its land – either from lumbering or from other activities, such as mining – put the rain forest at risk.

Getting a short-term livelihood or profit from the rain forest can bring troubling long-term consequences. Most rain forest species can live only in the rain forest environment, so the loss of that environment means the loss of the species. Since there are more species in the rain forest than anywhere else, rain forest destruction presents the greatest single danger to genetic diversity in the world today.

The loss of large amounts of plant material when the rain forest is cut down means less carbon dioxide is taken from the air; in addition, the air gains carbon dioxide when the cleared plant material is burned, which it usually is once the tree trunks have been removed. Both of the processes contribute to the greenhouse effect and add to the possibility that the earth’s climate will be disturbed by excessive warming.

The disappearance of root systems means that the abundant rain water cannot be held; this water washes away and adds to the risk of floods. The flooding is exacerbated when the thin topsoil washes away as well and accumulates as silt in rivers and streams. The rocky earth that is left behind reflects more light and heat into the atmosphere, adding to the likelihood that the climate will get warmer. The likelihood goes up further when the loss of plant material brings diminished could cover. This means not only less cooling but also less rainfall. Within the rain forest’s original boundaries, the process known as desertification results from the loss of clouds, rain, and topsoil; outside the forest’s edges, deserts form because clouds and rain that once blew in from within the forest no longer do so.

While there is still some debate over the extent of global warming – it is known that carbon dioxide concentrations in the atmosphere have gone up by one fifth in this century, but the evidence for actual changes in temperature are suggestive but not conclusive – there are well-documented cases of desertification and of flooding due to siltation from a number of rainforest regions that have undergone extensive cutting.



Many nations are taking steps to protect the tropical rain forests within their borders by creating parks and nature reserves. But it is clear that this kind of action can protect only a fraction of the world’s rain forest lands. Maintaining parks and reserves is expensive, especially for governments who are trying to meet the competing needs of other people for income and for land on which to live.

Juan Guevera’s job is to help the farmers who live in the area around the city of Pucallpa, in the part of the Amazon Basin that lies in Peru, meet their needs for food and income. For many years, these farmers have relied on a kind of agriculture known as slash-and-burn, which involves burning the rainforest plan cover to create plots for cultivation. Because land cleared in this way is only good for a couple of growing seasons, and because the population in the area is rising rapidly, the net effect of this kind of agriculture is a significant loss of rain forest, and no significant improvement in income or nutrition.

Among the effects of damage to the rain forest in the Peruvian Amazon has been a change in the annual patterns of river flooding, and this change in turn has put the survival of a number of native species of Amazonian fish at risk. They face a further challenge from species introduced for commercial purposes from outside of the Amazon Basin, some of whom are better adapted to the new river patterns. Fish catches from area rivers have declined in recent years.

Juan Guevera is helping farmers in the Pucallpa area get involved with aquaculture, or fish farming, as an alternative to slash-and-burn agriculture. The farmers build fish ponds and Guevera’s agency, called IVITA, provides them with advice and with fingerlings. The ponds are integrated with other activities on the farm: nutrients in the pond come from the wastes of pigs, ducks, and chickens, and the pond bottom provides food and fertilizer for the farmers’ gardens. Such integrated aquaculture keeps farmers’ costs low, which is particularly important for farmers living at the rain forest’s edge, as the cost of transporting their products to market is likely to be relatively high, due to their distance from urban centers, and therefore they must, in order to be competitive, keep all other costs low.

Duck droppings nourish zooplankton on which fish feed in integrated aquaculture project of IVITA in Pucallpa, Peru

Integrated aquaculture in the Peruvian Amazon has many benefits. It provides a source of nutrition and of income for farmers who might otherwise engage in a kind of agriculture that would damage the rain forest. A further benefit is that the ponds are helping to maintain the native Amazonian fish species. IVITA monitors and studies the local species, and where appropriate encourages farmers to raise these.

The solution that Juan Guevera and the farmers he works with have developed is part of a growing international consensus about how to keep rain forests alive. In the past, the need to protect an endangered environment almost always led to calls for new parks and reserves – for effectively removing human populations from everyday contact with that environment. It has been and remains politically and economically difficult for struggling countries to do this. The new consensus is to find a way that people can coexist with the rain forest. One way is to live at its edges and engage in activities that sustain rather than harm the forest. If it can be shown that the long-term benefits of such practices, not just for the rain forest ecology and the global environment, but for the well-being of the people who live in and near the rain forests, outweigh the short-term profits from lumbering, mining and slash-and-burn agriculture, then the rain forests will face a more secure future.


RESOURCES on  Biodiversity, Energy, Global Climate Change, the Environment, and other subjects: Links with detailed information are available on the Horizon Solutions Site.


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One Second Before Sunrise, Program I



Documented in One Second Before Sunrise, Program I

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Submitted by:

HORIZON International

Information Date: 1990-01-01
Information Source: OSBSI, Study Guide

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