Continent-Hopping Species Mean Tastier Meals

CHURCHVILLE, Va.—We all know the world has a serious problem with "alien" species.

Imported snakes are seen as a potential threat to rare bird species in Hawaii. Scotch thistles invade Australian crop fields. English foxes and rabbits threaten the habitats of small Aussie mammals. The list goes on.

Can the planet's biodiversity be protected against "alien invasions" in this age of international trade and travel?

Man has long been a major factor in these invasions. His early sailing ships were the first major "cruise liners" for traveling wild species.

Today we not only have more and bigger ships, but airplanes and those ubiquitous freight containers, which travel to every corner of every continent. The opportunity for "illegal immigration" is great, as are the dangers to native species.

BUT HUMAN travel has also established beneficial "aliens."

—Wheat originated in Asia Minor, perhaps in Syria and Afghanistan. It proved to be one of the most productive and nutritious plants on earth.

—The wild ancestors of today's cattle and buffalo were found in southern Europe, western Asia and northern Africa. Now mankind takes them anywhere they can produce milk or pull plows.

—Corn originated in Mexico, but the Pilgrims found it growing as far north as New England. American Indian tribes spread this productive grain thousands of miles from its original home. Spanish conquistadors took seed corn back to Europe and then to Africa, where it has become the dominant foodstuff.

—Bananas originated in south Asia, but are now more important to the diets of people in Africa and Latin America.

—Coffee is probably native to Ethiopia, but almost none of it is grown there now. Instead our coffee comes from trees planted and nurtured in the warm highlands of places like Brazil, Colombia, Kenya and Indonesia.

THE WORLD has millions of plant species, and yet we depend on only a few hundred of them for foods and beverages. The plants and animals we raise today are the winners in a global contest for utility going back 20,000 years.

Without "traveling genes" America wouldn't have wheat, cattle, horses, apples or coffee. Africa would be without most of its major food crops, including corn, rice and yams. The world's salad bars and fruit plates would be meager and far less tasty.

New Zealand might suffer the world's sharpest loss in quality of life if every country returned to native species. The country has imported virtually all of its food plants and animals. The original Maori settlers had to subsist on hunting a few bird species, seals and whales. Even the "Maori rat" is an immigrant.

A country composed of two large islands, New Zealand has only a few native vegetables. The islands have no native fruit trees. Yet today the country is a major fruit grower.

WE SHOULD also understand the world is not losing species very rapidly yet. Most of the known extinctions in modern times have occurred on islands.

As Brian Groombridge, editor of the "Red List of Threatened Animals," notes, "Very few extinctions have been recorded in continental tropical forest habitat, where mass extinction events have been predicted."

Mass extinction of plant species has not occurred because of mankind's age-old search for the best crop plants, and because modern research has tripled plant yields.

NOW RESEARCH is finding still more ways to raise more food per acre, opening the way to feeding the expected peak human population (8.5 billion in 2035) without taking more land from nature.

—The newest wheat varieties yield up to 18 tons per hectare, compared with traditional yields of one ton from the same land.

—Today's best dairy cows produce 15,000 pounds of milk per year, at least eight times as much as the traditional dairy cattle still being tended and milked in India.

—A plantation full of Georgia yellow pine produces three times as much wood per year as a Georgia native forest, 15 times as much as a Swedish wild forest. Cloned yellow pine in coastal Brazil produces 50 times as much as the Swedish forest.

We don't dare return the continents to a native-only species state. But we must be more careful in the future when testing foreign species, even if we believe such testing will reap important benefits. And we need to increase our vigilance against wild species' hitchhiking on cars, ships and planes.