Q: There's been some confusion about what the term "biodiversity" means. Can you define it for us?
A: Few other words in my memory have spread around the world faster. Biodiversity is meant to be all-inclusive it's the genetic -based variation of living organisms at all levels, from the variety of genes in populations of single species, through species, on up to the array of natural ecosystems.
Q: What is the value of biodiversity?
A: I recognize three large domains of benefit. One is the maintenance of our ecosystems in healthy condition. Recent studies have shown that the greater the variety of animals and plants present in an ecosystem and maintained at the original levels, the more efficient is the functioning of the ecosystem and the more stable it is likely to be over the long term. The second domain of benefit for humanity is as a source of new pharmaceuticals, crops, fibers, petroleum substitutes, and other products. There is potentially great economic wealth in the still unstudied reservoirs of biodiversity. And then, finally, is the property that I call "biophilia," which is the natural affiliation humans have for natural environments.
Q: What are some examples of the benefits of biodiversity?
A: I think the most dramatic of recent times has been among the pharmaceuticals. Many are familiar with the uses of alkaloids from the rosy periwinkle, a small plant of Madagascar. These substances have proved to be a highly effective agency in treating and curing Hodgkin's disease and acute lymphocytic leukemia. The value of rosy periwinkle products is now in the vicinity of $200 million a year. Less well known, but in a way even more spectacular, is cyclosporine an immuno-suppressive substance from an obscure fungus originally found in Norway. It is so effective in suppressing the natural action of the immune system, which would otherwise reject the transplanted organ, that it is the basis of the entire industry of organ transplant. Some 40 percent of U.S. prescriptions are for pharmaceuticals derived from wild plants, animals, and microorganisms. So, we're talking here of a multi-billion dollar industry.
Q: You mentioned "biophilia" the affiliation for nature as a benefit of biodiversity. What evidence is there for biophilia?
A: When I coined the word in 1984, I was using a plausibility argument, namely, that it is hard to imagine how humanity could have evolved over 2 mil lion years in the midst of natural environments, depending on an intimate knowledge of them for survival, without having some kind of built-in learning ability and bonding potential. In the last 10 years, a fair amount of evidence has accumulated to indicate that such an innate human tendency does exist.
One of the most persuasive findings is that by Gordon Orians and his colleagues that human beings gravitate toward what they consider to be the innately ideal human environment, namely a position atop a promontory overlooking a park-like savanna and a body of water. And there are other studies indicating that just the nearness or even the depiction of natural environments is psychologically restorative.
Q: How do you explain people living in cities, which is the antithesis of these conditions?
A: There are also millions of cattle living in stockyards. People move to cities for social stimulation, but above all to make a living. Once they've succeeded financially, notice what they do either move to a penthouse overlooking a city park, or get a second home in natural surroundings.
Q: Some people have questioned the accuracy of estimates of species extinctions. Is there really an extinction crisis?
A: We don't know the exact rate of extinction, but we can make a round estimate by using what we know about the relation between habitat area and species numbers that is, when the size of a habitat is reduced, the extinction rate rises. This relation can be reduced to a simple mathematical relation known as the "species-by-species curve." The rule of thumb is that when a habitat is reduced to one-tenth of its original size, the number of species eventually drops in half.
If we apply this formula to tropical forests where more than half of all plant and animals species are found, and where we have reasonably good data on habitat destruction we come up with a minimum figure of about a quarter of a percent of the species committed to extinction each year. This figure doesn't include other habitats or other causes of extinction like disease, over-harvesting, and so on. So this is really a very conservative estimate of current rates of extinction.
Q: But isn't extinction natural?
A: Human-caused extinction is emphatically not natural at all because the current extinction rate is up between 1,000 and 10,000 times over what it was before humanity came onto the earth, and that is far in excess of the rate at which new species are being created. So we are quickly running out of the capital that took many millions of years to create.
Q: Some say that saving species is a luxury. Can we really afford to save species?
A: The answer to that is twofold. One is that the Library of Congress is a luxury; the National Museum of Natural History is a luxury; the Louvre is a luxury. The biological diversity of a country is part of its national heritage, and it is also comparably older and more complex. Moreover, it will have great benefits for countless generations to come. It is absurd to call the saving of biodiversity a luxury.
Q: What about the move by The Nature Conservancy and others from protecting small refuges towards safeguarding entire ecosystems?
A: I think we should be doing both. The emphasis certainly is shifting from individual species in small fragments of ecosystems with hundreds or thousands of species, and that is a crucial improvement in our strategy. But at the same time, I am an enthusiast for microreserves little patches, maybe just a few acres in extent, here and there because these fragments, many of them together, add up to a great deal of natural environment. And many of them, while not holding endangered bird or plant species, may very well be holding endangered species of insects, fungi or other small creatures.
Q: Where is conservation headed?
A: Into increased public awareness, assisted by more sophisticated environmental science, that is, increasing knowledge about the nature and distribution of biodiversity itself, and the origin and the maintenance of ecosystems under natural conditions.
Q: How do you deal with anti-environmentalists?
A: Educate, educate, educate. Keep talking, keep pointing out, keep explaining, keep demonstrating, show the wonderful beauty and promise of the natural world.