Edward O. Wilson is an entomologist specializing in ants, the recognized leader of biodiversity studies, the founder of sociobiology, and a talented writer. Combining impeccable scientific credentials with the ability to communicate with the lay public, Wilson pleads for the reversal of what he calls “the sixth great extinction spasm,” the destruction of a large fraction of living species within a single human generation.
As a student of ants, Wilson looks at issues of preservation, ecology, and biodiversity in ways different from many people, even different from many biologists. He does not focus only on the possible disappearance of the spotted owl, or large mammals, or majestic birds of prey, although he understands the appeal of such animals to the public. When he speaks of a diverse biosystem, he includes all plants and animals, no matter what their size, aesthetic attraction, or apparent usefulness. He is just as concerned about the thirty species of feather mites that live exclusively on the feathers of a particular species of parrot as he is about that bird or the tree in which the bird lives. From tiny parasite to huge tree, all living things are parts of ecosystems.
The problem he brings before the reader is that 90 percent of all species now living on the earth have never been described by scientists. For all intents and purposes, no one knows they exist. Many may become extinct before they are understood. At first glance, this might seem to be strictly an academic issue, of interest only to biologists. Why should the lay public worry about obscure and undescribed fungi or insects? Wilson’s answer is twofold. First, some of these species may have economic value, either as food sources or sources of medicine. Humanity cannot risk destroying a possible natural cure for cancer out of ignorance. Second, the loss of a species or a number of species may lead to the collapse of an entire ecosystem. The consequences of human actions may be far more widespread than anticipated.
Wilson begins with a discussion of small-scale and large-scale annihilations of life, ranging from the fall of a tree in a rain forest to the destruction of an island by volcanic eruption and finally to the five great extinctions of the last half billion years, extinc- tions in which 90 percent of all species living at the time may have perished. The lesson he wishes the reader to draw from these accounts is that nature easily recovers from localized destruction. It can even rebound from a great extinction. Biodiversity can be restored. The time required for such a restoration on a planetary scale, however, is measured in the tens of millions of years. Unlike localized destruction, which can be restored within a few years, the global destruction that humans could inflict on the planet Earth in a single human lifetime cannot be repaired in millions of lifetimes.
The second section of the book is an excellent popular account of current views of evolution and related theories in biology. To understand the significance of biodiversity, one must first understand taxonomy, classification, evolutionary theory, and ecology. Aided by clear illustrations, Wilson provides a series of lessons in biology worthy of the great teacher he is. In doing so, he also acknowledges the limitations of scientific truth. Sometimes, the best that science can offer is a concept that is provisionally acceptable to a majority of scientists. Wilson makes clear when and if he is presenting the consensus view or his own personal opinion. He also provides the alternative theories. The provisional nature of science is brought out most explicitly...
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in his discussion of the definition of species, the most fundamental concept for bio- diversity and systematic biology. He concedes that the currently accepted working definition of a species as “a population whose members are able to interbreed freely under natural conditions” may be at best a pragmatic compromise that works most of the time. Scientists are not as certain about truth as some journalistic accounts imply.
In his final section, Wilson writes about the impact of humans on biodiversity. The history of human effect is dismal. No matter what their culture or race, the introduction of humans to a new ecology has led to the mass destruction of large mammals and flightless birds. This was true for North America, Madagascar, New Zealand, and Australia, whether the humans were Paleo-Indians, Polynesians, or Dutch sailors. More recently, habitat destruction has become the most significant cause of extinction, with the introduction of exotic animals into ecosystems second. Overharvesting is relatively insignificant. One example consists of fresh-water fish species. When habitat destruction is defined as either the physical destruction of the habitat or pollution of the habitat to an extent that it becomes unusable by a species, habitat destruction has been a significant cause in more than 90 percent of known fish species extinctions within recent historical times.
What makes the problem of habitat destruction so complicated is that solutions are necessarily international. An example is Bachman’s warbler, a bird that bred in the riverine swamplands of the southern United States and that is now thought to be extinct. Its habitat in the United States is abundant; however, it winters in the forests of Cuba, which have been destroyed for sugarcane agriculture. Likewise, the habitat of Kirkland’s warbler in Michigan might be preserved, but its wintering grounds in the Bahamas are still under threat.
Complicating matters even further are two realities of human population and resource distribution. The most biodiverse regions of the earth are the tropical rain forests, which happen to be in some of the poorest countries that also have the fastest-growing populations. In North America and Europe, habitats can be saved by declaring them as parks and closing them off to commercial exploitation. In the rain forests, the solution is more complicated. Any solution must recognize that the first obligation of humans is to feed themselves and their children. Second, the human population will triple by the middle of the twenty-first century. The pressure upon habitats will be tremendous, even in environmentally sensitive societies.
Wilson’s solutions are in the context of what he calls the “New Environmentalism,” a recognition that there is practical value in wild species. Perhaps overoptimistically, he claims that “there is no longer an ideological war between conservationists and developers.” According to Wilson, both sides recognize that a healthy economic return is dependent upon a healthy environment. Accompanying this economic approach to the environment is a shift in attention from the so-called “star species”—those that attract media attention, such as pandas, tigers, or redwoods—to the environments in which these star species live. Simply because the star species become extinct is not a reason to abandon preservation of the ecosystem. There are many species of equivalent significance still in the ecosystem, even if not of equivalent beauty, size, or cuteness.
Wilson’s plea ends with a set of very specific recommendations for both the very near future and two generations hence. First, Wilson calls for a survey of the world’s flora and fauna, to be carried out over the next fifty years. The realities of economics and politics make it difficult to preserve until it is known what exists to be preserved. This will require, among other things, increased funding for the training of systematists as well as support for their research and publication. Second, bioeconomic analysis must become part of routine land management. Better knowledge of the wealth that species represent must become more widely known. Third, sustainable development must be promoted. The inefficient exploitation of natural resources in the Third World must be reversed. Blame can be divided among both the wealthy nations, which exacerbate the situation with their trade and other economic policies, and the poorer nations, which desperately need population-control policies if the human species is not to overwhelm all others. Fourth, Wilson promotes saving what species remain, whether in the form of seed or gene banks, genetic stock in zoos or gardens, or (when and where possible) in natural ecosystems. Wilson’s last recommendation is to restore the wildlands. Underlying all of his recommendations is the belief that biodiversity is a public resource, to be defended not simply by ethical pressure or economic incentives but by force of national and international law.
For those readers wishing to explore particular issues more deeply, Wilson supplies notes that double as a bibliography. As an aid to those readers whose grasp of the vocabulary of biology is limited, he provides an excellent glossary of technical terms, that also includes very brief biographical sketches of important scientists.
Wilson’s book is very optimistic. The villain, to the extent Wilson identifies one, is ignorance, not greed. Greed is a very difficult motive to overcome. Ignorance, on the other hand, can be overcome. If Wilson is correct and the New Environmentalism is the wave of the future, if education can reverse current economic policies among the industrial nations and resource exploitation policies among the developing nations, and if the human race will stabilize its growth during the next two generations, then there is hope. If not, then the sixth great extinction spasm will continue and biodiversity on this planet will end in a wink of geological time, perhaps never to be restored.
Sources for Further Study
Audubon. XCIV, November, 1992, p. 124.
The Christian Science Monitor. October 22, 1992, p. 11.
Library Journal. CXVII, November 1, 1992, p. 114.
New Scientist. CXXXVI, November 14, 1992, p. 43.
The New York Review of Books. XXXIX, November 5, 1992, p. 3.
The New York Times Book Review. XCVII, October 4, 1992, p. 1.
Newsweek. CXX, October 19, 1992, p. 69.
Science News. CXLII, September 26, 1992, p. 194.
Scientific American. CCLXVI, March, 1993, p. 146.
Time. CXL, November 16, 1992, p. 101.
Washington Monthly. XXIV, October, 1992, p. 56.
The Washington Post Book World. XXII, September 27, 1992, p. 1.