Why, we may still ask, make such a fuss about agricultural biodiversity? After all, it’s been there since plants started growing, and it’s not going to go away.

Wrong. The diversity of food — of the plants and animals that we eat, of their relatives that grow in the wild, and of all the genetic information that exists in profuse combination within those organisms — is not unlimited. As we have seen elsewhere in this section of the AboutBiodiversity Web site, and will see in other sections as well, humans and their habits have put agricultural diversity under a terrible strain.

We have reduced the amount of land that’s available for the growing of food. Just as we have eliminated habitat where tigers, bison, and hundreds of birds once lived, development has destroyed the habitat of crops.

We have damaged the soil on the remaining land through erosion, over-watering, excessive use of chemicals, and monoculture.

Through our reliance on chemical pesticides and herbicides, we have helped create superpests that are skilled at attacking the food we grow.

We have increased the demand on the food that we do grow, through rapid population growth.

Each of these actions, and many others, has taken a toll on the biodiversity of food, and done so at a time when that diversity is badly needed — for we will have many millions more mouths to feed in the years to come.

For years now, and especially in those years following the Green Revolution, agricultural scientists have been squeezing more and more yield out of our basic foods. Plant breeders have bred defenses against pests and disease into wheat, maize, potatoes, and rice, so that more of the food survives and makes it onto somebody’s plate or bowl.

At the same time, the scientists have raised the foods’ yields. They have produced rice with more grains per stalk, potatoes and cassava that contain more starch, maize and wheat packed with more nutrition than ever before. All this has been done by what is called “conventional plant breeding” — patiently making crosses between plants with differing characteristics, just as Gregor Mendel had done with his peas back in 1866. Now some scientists are attempting to do the same thing through biotechnology, and some of them are succeeding — although so far, biotechnology is producing far more profits for big international corporations than comfort for starving people.

A time of flattened growth?
But now, some scientists are worried that they are reaching the limits of greater food production. They speak of what they call a “plateau,” a time of flattened growth that follows a steep upward curve in plant breeding success.

The plateau was noticed first in rice, the grain that serves as the major food for half of Earth’s population. Scientists at the International Rice Research Center, in the Philippines, have had great success in breeding high-yield, insect-resistant rice since the days of the Green Revolution. But in recent years the successes have come more slowly — bad news at a time when some researchers are predicting that rice yields would have to double by 2025 just to keep up with population demands.

Obviously, this is no time to waste the biological diversity of the foods we eat. Agricultural biodiversity has never been at top of science’s list of important biodiversity issues. It's not as glamorous as saving whales and pandas. But that needs to change. We need more than ever before to search for diversity, conserve it, and use it in the growing of “new and improved” foods. Without the diversity of the crops we eat, we eventually may have nothing to eat at all.

This ends the AboutBiodiversity pages on the diversity of the foods we eat. You may return to the AboutBiodiversity home page by clicking here. There you can find links to other sections of the site, such as the one on soil and others (forthcoming) on engangered species, extinction, invasive species, the biodiversity of water, the year that was devoted to observing biodiversity around the world, and many other subjects. All the sections will be updated from time to time with information and images about new and important events and research; the AboutBiodiversity home page will let you know about additions and updates.

Photo of African boys: International Plant Genetics Research Institute.

Site sponsored by The Bay and Paul Foundations. Contents Copyright © 2000-2003 by Fred Powledge. This site was last changed on 20 June, 2003

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