Read an Excerpt
Rain Forest in Your Kitchen
The Hidden Connection Between Extinction and Your Supermarket
By Martin Teitel
ISLAND PRESSCopyright © 1992 C. S. Fund
All rights reserved.
GENES, HYBRIDS, AND THE LOSS OF BIODIVERSITY
We live in a world that is incredibly and beautifully diverse. Glance out your window. In your backyard you might see dozens of different tree types and shapes, every possible color of flower, shrubs and bushes of many heights, perhaps a small tilled plot with red, green, and yellow fruits and vegetables hanging on bushes and vines. In a city street you might see people, dogs, cats, and birds of all sizes, shapes, and colors. Unseen at a glance is the multitude of bugs, spiders, and worms that fly, creep, and burrow across our planet, or the astounding numbers of microscopic plants, animals, and bacteria that live in the soil and under water.
We are so used to this diversity that we often overlook its significance: it is the most powerful biological fact of our planet.
What is the value of this complexity? Why is the world around us so elaborate? Because nature needs a large pool of genes to select from as she reweaves genetic combinations. Options are critical in an unpredictable world. In geologic terms, glaciers come and go; oceans, lakes, and rivers appear and disappear; and the climate fluctuates. Even in the short term, habitats change radically when dams are built, pastures paved, forests stripped, and deserts overrun by dirt bikes. Genetic options provide the flexibility that ensures life. The organisms that adapt to change survive; those that do not, become extinct.
Adaptation hinges on the successful reworking of available genetic materials; it is a time-dependent, slow process. The gradual nature of genetic change is one of the significant causes for concern about global warming, the greenhouse effect. For if environmental changes outpace genetic remixing processes, extinction becomes probable for the affected species. Only a diversity of genetic traits, housed in a diversity of species, ensures that some will continue to live—for at least the short run. Those species adequately equipped with genetic remixing materials will survive to pass their "robust" genes on to their progeny. Those without a wide selection, broad repertoire, and varied genes will not survive, will not be able to reproduce, or will not reproduce much. Genetic uniformity, then, works against species survival. The species that hedge their bets by fielding the most diverse set of individuals, who embody the most diverse set of genetic instructions, are most likely to adapt—and to prosper.
Safety in Numbers
We can speak only theoretically of how an individual's or individual species' genetic diversity provides a secure foundation for its long-term survival. Realistically, communities of biological entities—plants and animals—survive by virtue of shared, intertwined diversity. When overall biological diversity is low, extinction can occur regardless of the richness of any one species' genetic diversity.
From the tropics to the tundra, even a single seemingly insignificant change can set off a biological chain reaction. The disappearance of a particular bird or insect essential for disseminating plant seeds or cross- pollinating plant blossoms can reduce the numbers of weeds, shrubs, or trees in a habitat, in turn eliminating necessary food or shelter for other species of animals. Biological diversity therefore cannot be viewed on a genetic or species level alone, because few if any plants or animals exist in the world without some important connection to living things around them. If we make the world inhospitable for one living thing, we cannot know for sure what other living things we will be killing off at the same time.
While late-night comedians profit from poking fun at people who "fuss" over snail darters or spotted owls, the protection of such creatures is much more serious than the one-liners reveal. Each time we subdivide an orchard or irrigate desert land we risk snapping critical links in biological chains. Once we have ensured the extinction of one form of life and belatedly discovered that we are responsible for an even greater loss, it is too late: what is extinct is gone forever.
Obviously, nature is quite resilient as well. If this were not the case, life on this planet would have ceased long ago. The first extinctions would have had an irreversible domino effect. It is not extinction itself that is so threatening, but the rate at which it occurs. Scientists have estimated that the rate of bird and mammal extinction between 1600 and 1975 rose between five and fifty times from previous rates. The rate at the end of the twentieth century is projected to rise between forty and four hundred times what scientists consider normal.
Nature has a lovely, stately pace, a pace that works best for growing, building, dying, and the other natural processes that occur millions of times all over our planet every day. Examples abound: touring Yellowstone Park after a huge fire, one marvels at the elaborate, interlocked growth processes that spring to action, sometimes within weeks of a seemingly devastating disaster. Nature abides such cataclysms. The forest recovers—it can handle a fire in its own way, at its own pace.
But bulldozers, pavement, sudden changes in the composition of the air or water or rain—these human-made onslaughts frequently overwhelm the ability of biology to accommodate, adjust, and survive. The stripping of the world's rain forests, the changed climate around our cities, the worldwide trend to desertification—these are just a few examples of human-induced change that destroys the very fabric of the natural system. If we keep this up, we are going to be in for some horrendous calamities, perhaps more quickly than now imagined.
How many species can a given ecosystem lose before it no longer works as a system? We do not know. But biologists Anne and Paul Ehrlich have invented a compelling analogy based on an aircraft held together by many thousands of rivets. Flying along in this craft, we could safely knock out one of the rivets. Indeed, if as we fly we keep poking out rivets one by one, we would be able to go on safely for some time because there are a great number of rivets, and airplanes are very strong. Still, common sense tells us that eventually we would poke out just one more and the craft would come apart. There is no way to know which of the rivets will be the pivotal one—until we have poked it out and it is too late.
The Ehrlichs warn us to quit pushing before it is too late, before the system that sustains our lives, and the lives of all other living things, loses its capability to carry us.
Biodiversity and Food
The earliest uses of physics-based power were centered around food—water wheels to grind grain, for example, or sailboats to trade food and spices. Even today, much of our interaction with the natural world has to do with getting food, as we clear grasslands and forests for crops or animals, dam and divert river and lake waters for irrigation, and terrace mountains into cropland. Every person needs to eat in order to live. The fortunate among us eat every day. So no matter how urbanized we may be, we maintain immediate and direct contact with the natural, biological processes of the world through our daily meals. While there may be little that a person feels able to change in distant rain forests or high-mountain dam sites, we can exploit our direct connection with biology via how and what we eat and where we get our food.
We have long been admonished to eat a mixed and varied diet. But the reality is that 50 percent of the calories consumed around the world every day come from just three crops: corn, wheat, and rice. Combine this uniformity of diet with the fact that most of these crops are grown from just a few plant varieties and you have the potential for a severe, potentially catastrophic narrowing of the global edible-plant gene pool. For example, in the United States, six varieties of corn account for 71 percent of the yearly crop, ten varieties of wheat dominate the harvest, and four varieties of rice make up two-thirds of the planted acreage. In Japan, two-thirds of local rice varieties have been lost in this century. India had 30,000 varieties of rice fifty years ago but today depends on just ten strains.
Most, if not all, of the varieties in popular use today are inbred or hybrid varieties. Indeed, the food-crop biodiversity crisis is largely rooted in the use of nontraditional plants. In scientific terms, inbred varieties (whether plants or animals) result from generations of crossing closely related individuals, producing offspring that are practically uniform genetically. Hybrid varieties are the offspring of genetically dissimilar parents. Typically, the parents of hybrids have been inbred for a few specific traits; the offspring manifest the carefully chosen traits of the parents.
It is not that inbred or hybrid plants are intrinsically all bad; in fact, they often grow faster, yield more, and harvest more easily than traditional varieties. That is why they are so popular. But they are carefully conceived for these characteristics, and they have a narrower, less flexible genetic base as a result. While they may yield well, to do so they usually need more fertilizer, more water, and more protection from pests and diseases than do traditional plants. Because of these requirements, modern, "improved" plant types tax the resources of the planet.
Moreover, inbred and hybrid plants and animals are often the products of large corporations. As their virtues are extolled through national and international advertising, farmers are enticed away from planting traditional seeds. In some cases, big corporations control the local seed market to such an extent that farmers are forced, not cajoled, into switching to nontraditional varieties. If farmers have no stock of the older, more genetically diverse seed, once they stop growing it, it is in danger of becoming extinct. This is how, in just a few years, important plant varieties can be lost to the world forever.
Seed banks, botanical gardens, and wildlands preserves act to prevent this type of extinction from occurring. Seed banks in the United States and around the world store collections of seeds, ostensibly to preserve their diverse genes for the future, when they might prove useful in increasing plant productivity or fending off disease. Botanical gardens and preserves maintain living collections of rare plants for the same purpose. For either system to work, the seeds must first be located and collected, then handled in a way that protects their genetic structure and viability.
Neither of these preservation techniques are fail-safe, and their implementation suffers from lack of funds. Untold thousands of plants have already been lost forever, and more will go extinct before anyone has a chance try to bank their seeds or otherwise save them
The seed bank situation is particularly alarming. The United States has a National Plant Germplasm System in which seed samples held at regional repositories are backed up by duplicate accessions at the Fort Collins National Seed Storage Laboratory (NSSL)—at least that is how the system is supposed to work. Henry Shands, director of the national system, warns that that is only an ideal at this point. Shands reports that 25 to 35 percent of the system's seed samples are in danger and need to be grown out for a variety of reasons, such as to replenish seeds with low rates of germination and samples of inadequate size, or to verify that samples held at regional and national banks are indeed the same plant, or simply to produce the seeds necessary to provide for a back-up accession. Ongoing budget limitations ensure that it will take at least a dozen years to grow out the seed samples now at a crisis point, says Shands; any new accessions must queue up behind.
A 1990 study by the National Academy of Sciences found the situation even graver. The academy reports that "a large proportion (almost 50 percent) of the accessions at NSSL are below the minimum desired size (550 seeds). Regeneration of these samples is urgently needed."
A recent study conducted by the International Board for Plant Genetic Resources revealed peril at the international level, finding that a majority of the world's collected crop germplasm is not securely stored and some of it has been irretrievably lost due to financial and technical shortcomings. Seven of the seventeen "designated base" gene banks evaluated, including the NSSL, did not meet the board's registration standards. These seven represent exactly half of the storage space surveyed and 60 percent of the germplasm stored today.
Botanist Gary Nabhan, author of Enduring Seeds, puts these reports in perspective with his reminder that of the 160,000 crop samples delivered to U.S. Department of Agriculture plant introduction stations since 1898, only 5 to 10 percent are still alive and accessible. As a kind of "survival insurance, seed banks may be fine," says Nabhan, "but there will be tremendous losses if we assume that they are all we need." Botanical gardens and preserves, too, are limited in what they can save, as well as by the biological fact that the long-term inbreeding that can occur within protected populations can itself destroy genetic diversity.
Why go to the effort of preserving ancient seeds and plants? Are we losing anything important—if the newer plants yield more and better?
Who knows, since currently insignificant traits might be priceless in the future. "For example," says Jack Doyle, author of Altered Harvest, "the genetic material found in one Ethiopian barley variety resistant to yellow barley mosaic now saves American farmers an estimated $150 million a year, and some Turkish wheat genes resistant to stripe rust have saved American wheat farmers $50 million annually since the 1960s." Closer to home, Kent Whealy, head of the Seed Savers Exchange, reports that the stringlessness of green beans hinges on one gene that is now incorporated in 99 percent of the snap beans grown in this country. If a disease attacked that gene, people would desire the older varieties. But would any be alive?
So who is encouraging the use of hybrid varieties? Consumers, because we demand plentiful, cheap beef, pork, and fowl, all of which are raised on volumes of hybrid grain, as well as unblemished produce of uniform shape and size. American farmers, because they prefer plants that ripen at the same time, hold up to mechanical harvesting, and produce bigger or weightier yields. And, most of all, seed companies, because inbred and hybrid plants are an entree to an expanded market for fertilizers and pesticides, and because they ensure annual seed sales, as the seeds must be recreated anew each year and are patentable. Not surprisingly, these companies are also typically heavily invested in biotechnology, a technology that makes a new spectrum of patentable plants possible—at un-natural speed.CHAPTER 2
A LINK OF STEELY STRENGTH
Agriculture is big business in this country. We not only feed our own quarter-billion citizens, but ship corn, wheat, and soybeans to the feed lots and cook pots of many nations around the world. Over the last century, the standard model in American agriculture switched from locally oriented family businesses to a huge industrial process in a conversion that, not incidentally, makes foreign marketing more achievable. One aspect of this evolution in agriculture is a trend toward monoculture—the growing of vast quantities of exactly the same thing.
The potato is a good example of this trend. In the United States, twelve varieties of one species of potato account for 85 percent of those marketed. But one variety, the Russet Burbank, garners the greatest acreage—about 40 percent in 1982. Why? The Russet Burbank is the "McDonald's potato," the fast-food company's pick for its french fries. McDonald's demand is farmers' command in the United States. And as the company grows internationally, it spreads its dependence on the Russet Burbank to acreage overseas.
While monoculture farming of inbred and hybrid plants and animals represents the fundamental element of the amalgamated link between diet and the loss of biological diversity, it is the meld of elements in the link that gives it its durable strength. Inbred and hybrid varieties require the use of pesticides and fertilizers, facilitate corporate control of farms and seeds, and provide a market for the techniques and products of biotechnology.
Why Poison Ourselves?
One of the sobering realities of the movement toward monoculture is the concomitant overuse of farm chemicals. The genetically uniform plants that are favored in modern agriculture are quite frail. While some of these plants show high yields, at least on paper, their successes depend on extensive outside help. The promise of miracle production from hybrid plants is fulfilled only if the plants are nurtured with fertilizers and protected by pesticides and herbicides. For example, since the introduction of hybrid corn in this country, farm use of fertilizer has increased tenfold. Hybrid and inbred plants are like athletes who can accomplish prodigious feats of strength and endurance—but only as long as they have access to steroids, pain killers, supplements, and other ultimately nonsustainable, self-destructive crutches.
Excerpted from Rain Forest in Your Kitchen by Martin Teitel. Copyright © 1992 C. S. Fund. Excerpted by permission of ISLAND PRESS.
All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.
Excerpts are provided by Dial-A-Book Inc. solely for the personal use of visitors to this web site.