Assistant Secretary for Research, Smithsonian Institution, Washington, D.C.
For 3 days in late September 1986, a group of about 60 distinguished scholars and scientists addressed capacity audiences at the Forum on BioDiversity at the Smithsonian and the National Academy of Sciences on the importance of biodiversity on our planet. In accordance with their dissimilar professional backgrounds, the speakers approached the topic from many directions. Judging from the active audience participation, the listeners clearly understood the perils to their own well-being presented by a loss of the Earth’s biodiversity. This book is based on that forum.
In this chapter I summarize what we heard (what the authors of this book have written), what we learned, and finally, what we might do to slow, or hopefully stop, the rapid, human-induced extinction of the Earth’s great variety of plants and animals.
The first keynote speaker (Chapter 1) warned that the diversity of plant and animal species is declining at a much faster rate than generally is realized. This disturbing assessment is exacerbated by our ignorance of just how many different species exist, especially among the terrestrial and marine invertebrates of the tropics. These creatures are both difficult to collect and even harder to identify, since few taxonomists in the world have the expertise to name them. There is a grave danger, therefore, that many as yet uncollected small plants and insects will inadvertently become extirpated without our even knowing that they once existed. Some of these unknown plants and animals could play important roles in our well-being, or even survival, yet they may never be recognized.
All forum participants stressed the need to maintain biodiversity, and a consensus soon emerged that the greatest threat to this goal today is from human activities. Human populations are expanding most rapidly in the tropics—the very area where biodiversity is the greatest. Thus pressure on the land to support even more people
results in the transformation of biologically diverse rain forests into pastures and monocultured crops, with only a minimal number of species being grown to sustain the burgeoning population. Altering a natural landscape to satisfy human needs for food and living space has been going on throughout the world for millennia. In most countries of the New World, such activities have accelerated rapidly following European colonization and the importation of modern technology.
Although human activity has directly caused the extinction of many recent species, the geological record indicates that massive destruction of plants and animals occurred episodically at distantly separated intervals long before humans evolved. Despite the enormous volume of debris and noxious fumes spewed by volcanoes into the Earth’s atmosphere, pollutants from these relatively few eruptions dwarf the total amount of devastation caused by mankind. Compared with past natural disasters, the destruction caused by human activity is of quite a different character. Today, species destruction by humans is intense, concentrated in time, and on a global scale not previously experienced in prehistoric times. Sediment loads of rivers, for example, have certainly varied in the past as a result of forest fires and earthquakes, but in time the damaged watersheds recovered and sediments lessened. Today, however, the watersheds, especially in the tropics, are degraded continually by human activity.
Whatever natural extinctions took place before the presence of humans is irrelevant, because today we are such, a dominant species that theoretically we have the understanding and the power to stop or at least to mitigate our destruction of the natural world. The practicability of this approach may be arguable, but several authors give specific examples of how whole new habitats, such as salt marshes, can be restored or how an extirpated subspecies of peregrine falcons can be replaced by a new, artificially created subspecies that seems to fill successfully the niche that was lost.
Although scientists have had isolated successes in restoring habitats or saving endangered species, the key to a more permanent equilibrium and therefore the long-term preservation of biodiversity will depend on effective population control in the tropical Third World. Some governments and many organizations are already working on this goal, but population control is a highly charged political and cultural issue not likely to be resolved until the incentive for large families disappears throughout the world.
One way of mitigating the environmental damage caused by inevitable population growth is to exploit the use of alternative human foods. Upon arrival in the tropics, European entrepreneurs tended to introduce temperate zone pulses and grains into their new colonial territories. Some crops, such as maize, adapted well, but shortly after World War II, in what was then Tanganyika, thousands of hectares were cleared and planted to grow peanuts. With little previous testing, the new crop was a disastrous failure both financially and environmentally. There are, unfortunately, many additional examples of such unsuccessful efforts in Africa and tropical Asia. Much innovative plant breeding has been done recently by international centers in Third-World countries. India’s wheat harvest, for example, has achieved self-sufficiency for the nation, although this accomplishment is dependent on relatively regular monsoons.
The same scientific advances that have led to increased local food production in the tropics have also inspired imaginative ways to fill the local animal protein needs of the rural people in tropical countries. Projects range from elaborate game ranching in East and South Africa to the development of simple facilities for restocking edible green iguanas in Central America. Not only have scientists successfully increased endangered animal populations through captive and controlled breeding, they have also been able to reintroduce these captive animals into their original habitats with considerable success.
In recent decades, animal breeding techniques have advanced to the point where embryos can be implanted between species within a genus. Thus, the relatively common eland antelope has been implanted with a rare bongo embryo and successfully carried to term. As our knowledge and skills improve, other rare mammals can be born to foster mothers to develop captive populations large enough for eventual reintroduction to their former habitats. Admittedly this is a slow and expensive way to maintain biodiversity and is clearly limited to a few mammal species. Such reintroductions, however, are worthwhile only if a reasonable facsimile of the original habitat exists. There is always the likelihood that all the essential components of the original habitat cannot be reproduced when the landscape is artificially restored.
The reaction of those attending and participating in the forum, however, seemed to support the idea that artificial restoration was well worth undertaking. We do indeed have an obligation to future generations to keep life on the planet as diverse as possible; for this participant, such is the principal message of this book.
What else did the audience learn from all these presentations? The scientists and scholars generally reported on work already published but seldom read by the layman. Judging from the questions from the audience, most were knowledgeable about the subject but undoubtedly learned many new details on all aspects of biodiversity, especially the magnitude of the problem.
Coverage by the major newspapers and journals spread the word beyond the forum attendees. The sessions closed with a national teleconference transmitted via satellite to more than 100 universities and other organizations throughout the nation during which the conferees questioned directly six of the principal participants. (An edited videotape of this conference is available from the National Academy Press.)
Although well publicized by environmental news standards, the critical messages generated at the symposium had to compete for the public’s attention with other seemingly more immediate problems, such as the threat of nuclear war, acid rain, and other global nest-fouling threats. World leaders, who must make hard economic choices, may be so overwhelmed by more acute problems that they may not choose to invest in the security of humanity by perpetuating biological diversity.
Despite the bleak picture of the threat of rapid extinctions, the technical advances in biology give hope for alleviation. Perhaps the symposium session most relevant to changing human behavior and to maintaining biodiversity was the last one: Ways of Seeing the Biosphere.
The concluding four speakers addressed the issue of human perceptions of and behavior toward the environment from the viewpoints of a poet, a theologian, a
philosopher, and an American Indian folklorist. The Native American gave graphic examples of how his culture views the natural surroundings: it considers human resources to be an integral part of the whole Earth rather than a force to dominate the terrestrial globe. The philosopher reinforced this viewpoint by reminding us that the whole Earth is a living organism and, therefore, we cannot treat humans differently from other living components. The theologian put human beings in the Judeo-Christian perspective as part of God’s total creation.
Thus an immediate—as opposed to a geological—solution to the problem of maintaining global biodiversity seems to depend on the collective behaviors and perceptions of people toward their habitat. The Western world in particular has been out of harmony with its environment and through temporary technical superiority has imposed its destructive standards of affluence on the rest of the world. Unfortunately, the Earth’s natural resources are finite and inadequate to support a global living standard equivalent to that of the developed countries. To keep the Earth reasonably habitable for humans in the centuries to come, natural forces will have to lower the human population and reduce the indiscriminate exploitation of the natural world. Controlled rational exploitation may be the answer, if the surviving humans have the foresight and sensitivity to carry it out.