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| TACKLING
MASS EXTINCTION OF SPECIES: A Great Creative Challenge Berkeley, California May 1, 1986
- in Madagascar, there were recently 8,500 documented plant species and probably around 170,000 animal species, with 60 percent of them endemic to the island's eastern strip of forest. At least 93 percent of the original primary forest has been eliminated.2 - in the Caribbean, with its 50,000 coral-reef species, whole communities are at risk through marine pollution. One-sixth of the world's oil is produced in or shipped through the Caribbean, and supertankers, plus offshore oil rigs, inject more than 100 million barrels of oil into the sea each year.3 - in Lake Baikal of Central Asia, the oldest, deepest and most remote large lake on Earth, there are at least 2,000 fish species, 1,500 of them endemic - and the lake is being polluted by more than 50 factories, including paperpulp plants recently established in its environs.4 - in the Cape Floristic Kingdom of South Africa there are 6,000-plus plant species, 70 percent of them endemic, in only 7,200 square miles (the 600,000 square miles of the northeastern United States feature only 5,500 plant species, and only a few hundred endemics). Yet the area suffers acute problems of encroaching agriculture, over-frequent fires and invasive exotic plants, threatening at least 2,000 plant species (or as many as are threatened in the entire United States).5 - in the Pantanal area of Brazil there are 44,000 square miles of wetlands, probably the most extensive and richest wetlands in the world. They support the largest and most diversified populations of waterfowl in South America; and they surely harbor a large number of endemic invertebrates. The area has been classified by UNESCO's World Heritage System as "of international importance". Yet it suffers increasing encroachment from agriculture, hydropower projects, and other forms of disruptive development.6 I have come across many other such portents of a major extinction episode underway,7 True, they are generalized in their documentation; in the main, they do not offer lengthy lists of individual species that have recently become extinct. But in addition, colleagues tell me of particular instances with species-by-species details, such as the 90 endemic plants and their associated animal species, discovered only a few years ago on an eight-square mile ridge of western Ecuador, and entirely eliminated today through logging and settlement agriculture.8 In short, there are abundant signs that we are witnessing a mass extinction. In the course of this paper, we shall look at the nature and extent of the phenomenon. We shall examine some of its mechanisms and dynamics. Above all, we shall ask how far it should truly matter to us, whether as scientists, conservationists or citizens. This writer will argue that from a biological standpoint it ranks as one of the greatest, if not the greatest, of all episodes in the history of life's four billion years on Earth; and that from a biological and every other standpoint we can regard it as one of the greatest, if not the greatest event of our time. We are unconsciously conducting a superscale experiment with Earth's biotas. And, it will generate a grossly impoverishing impact - unless we, viz. scientists, conservationists and citizens, decide to do a good deal more about it. Therein lies scope for another great event: the saving of species in their millions. So we face not only an outsize problem. We face an unprecedented opportunity: a challenge of uniquely creative scope. However true it is that we are witnessing a mass extinction, we witness it unwittingly. The progressive depletion of Earth's biotas is little noted, let alone investigated. In Central Africa, for instance, the 11,430-square mile Lake Malawi, with its 500-plus cichlid species, 99 percent of them endemic (the lake is only one-eighth the size of North America's Great Lakes, which feature only 173 species, fewer than 10 percent of them endemic), is threatened through pollution from industrial installations and proposed introduction of alien species.9 In Lake Victoria, with only some 300 endemic cichlid species, introduced predators among other problems are likely to reduce the flock of endemics by 80-90 percent within another decade at most. The evolution of Lake Malawi has engaged in explosive speciation, to produce an exceedingly rich "fish swarm" with greater differentiation than in any other tropical lake. Indeed Lake Malawi, together with the chain of other lakes in East Africa, harboring more than 930 endemic cichlids (plus more than 100 other endemic species), must be reckoned as far more significant for the study of evolution than the Galapagos Islands. Yet the basic biology of Lake Malawi, the leading lake in the chain, has yet to be elucidated, and there is next to no scientific program for long-term research of a substantive and systematic sort. There are many such ecosystems in the tropics: exceptionally rich, exceptionally threatened, and exceptionally interesting to the scientist. Yet the issue of mass extinction has remained a sleeper issue - until very recently, at least. During the past several years there has been intense scientific debate (engendered in major measure by the pioneering work of the Alvarez team on the Berkeley campus),10 with regard to the events at the end of the Cretaceous, leading to the sudden demise of the dinosaurs and their kin, together with associated assemblages of other animals. Yet there is hardly a fraction so much debate, let alone research, on the extinction phenomenon that is starting to take place on the planet right now all around us. The late-Cretaceous episode has even attracted the attention of many organs of the popular press. But when Time Magazine ran a cover story on the subject last year, comparing it with other major extinction episodes during life's history on Earth, it did not mention the remarkable episode that is taking place today - before our very eyes, as it were.
The current episode of mass extinction is clearly of concern to modern biology. For one thing, a sizable portion of life's diversity on Earth is being eliminated: we are witnessing the onset of a process that will, if unchecked, culminate in the summary elimination of millions of species. When we consider just the numbers of species involved, let alone the compressed time-frame of the episode (much less the unique cause of the phenomenon), we may suppose we are on the verge of one of the greatest extinction episodes to occur during the four billion years since the start of evolution. Eventually this mass extinction may well prove more far-reaching in its ultimate impact than others of the paleontological past, insofar as a large proportion of plant species are being eliminated along with animal species (on former occasions the plant kingdom was often little affected) - with all that implies for post-extinction recovery of biotas through evolutionary processes. For various reasons then, the extinction spasm impending may well rank as the greatest impoverishment of Earth's species since the first flickerings of life. This apart (if one may venture the heresy), there are other factors of current mass extinction that are significant to modern biology. The essential questions of evolution are far less likely to be answered (nor may all the right questions be asked) if the enquiry must be pursued through the medium of a grossly reduced spectrum of species. After all, the species is the basic unit of evolutionary biology, and each species has emerged as an ultrarefined experiment in biology. Moreover, whereas certain schools of evolutionary enquiry assert the preeminence of generalized phenomena such as adaptations, specializations, regressions and other trends, we cannot analyze these phenomena in isolation from the progression of the entities that display these trends, viz. species.11 Furthermore, the species is the basic unit of ecology too. An ecosystem, being composed of species together with their physical environments, is better understood when it is reduced to its component parts, together with the interactions of species with their environments and with each other. It is these interactions that are the proper focus of ecology. How shall we address the key questions of ecology without a full complement of real-world examples of how these questions are being addressed?12 If we lose a major proportion of extant species, will that not severely limit our options for studying determinants of diversity, population regulation, resource-sharing strategies, food-web structures, nutrient flows, and social systems - all of them central to our understanding of how creatures live in relation to their environments, whether gophers in relation to their habitat or humankind in relation to the biosphere? In addition to evolutionary biology and ecology, a good number of other branches of modern biology are critically dependent upon the entity of species as "an immensely useful ordering device for biological phenomena."13 Again, a proper array of species contributes to the ultimate full flowering of such subject areas as zoology, botany, taxonomy, systematics, ethology, comparative physiology, functional morphology and population genetics.14 Yet despite these cogent factors of concern for mass extinction, much of modern biology seems preoccupied with other priorities. The approach is revealed by funding patterns. The National Science Foundation is the main federal agency to support basic research in systematics, ecology and other fields that relate to species totals and extinction rates, with a budgetary allocation of $34 million a year. This is to be compared with the budget of the National Institute of Health, $4 billion. Of the NIH budget, $1.1 billion goes to work on cancer. Yet if all forms of cancer were conquered tomorrow, the average life expectancy of Americans would increase by only a few years. Meanwhile the survival of millions of unique life forms, with all that they contribute to the wellbeing of all humankind, is at stake. Put another way, were we to make no progress toward a cancer cure for another 50 years, the overall wellbeing of American society would not be much affected in terms of its essential functioning. But we have a lot less than 50 years, maybe only 15 years, to get to grips with the deadlines of tropical deforestation and other environmental degradation that leads to mass extinction of species.15 From the pragmatic standpoint of biology's future, and with respect to its basic raw materials in the form of species, is it not ironic that precisely when we are learning so much about the nature and origins of life, we are allowing so much of life's diversity to disappear, and to disappear in the twinkling of an evolutionary eye? It is not ironic that precisely at the time when we are learning how to exploit genetic variability through the quantum advances of genetic engineering, we are allowing entire stocks of genetic materials to be eliminated? Is it not ironic above all that precisely at a stage of so much blooming of modern biology, we are allowing manifold manifestations of life's diversity, indeed whole segments of life's variety and abundance, to be dispatched, and ostensibly with scarcely a thought? Will future generations of biologists not consider it curious that as we became aware of what was happening, we nevertheless continued with the established approaches to biology, with the former priorities and funding patterns? And that we continued that way for all the world as if the future would be a simple extension of the past, a case of "the same as before, only more so" - even though we were poised on the brink of one of the greatest dislocations in the entire course of life on Earth? Yet far from being ready to do much about the extinction episode underway, we do not even know how many species now exist. It is surely of interest to modern biology to know whether the planetary complement of species amounts to fewer than 5 mil-lion species (minimum estimate) or 50 million (highest present estimate). Nonetheless we do not have anything beyond a vague idea of how many species actually share the planer with us. Nor, at present rates of documentation16 and extinction, will we ever know, probably not to within 50-percent certitude. Yet we can now measure how far the Earth is from the moon at a given moment, almost one-quarter of a million miles, to within less than half an inch, i.e., to within 99.999999998-percent accuracy. Were a neighboring planet to reveal its own form of life, that would be considered exceptional news indeed. Yet we have only a rudimentary understanding of the nature and function of our own biosphere and its myriad forms of life. We now know more about certain sectors of the moon's surface than about the heartlands of Borneo. But the moon will remain around, undisturbed, for a good while to come, whereas the heartlands of Borneo look set to become radically modified within just another decade at most. Here we are, then, faced with what deserves to rank as the greatest issue of modern biology, and we do not even know how great an issue it is.
Whereas the status of Earth's totality of species is an issue that virtually by definition should be a major concern of modern biology, some observers may suppose that an individual species is a much more marginal affair; i.e., that it is an entity far less likely to offer much to biological understanding. But each species represents the outcome of evolutionary processes that have generated a discrete amalgam of genetic variability. Although intraspecies genetic differences may sometimes appear slight, they are often quite pronounced. An immediate idea of this "genetic plasticity" inherent in a species can be gained, for example, by considering the variability manifested in the many races of dogs or the many specialized types of corn developed by breeders.17 But even this gives only a very crude picture. There is much more to the situation. A typical bacterium may contain about 1,000 genes, certain fungi 10,000, and many flowering plants and a few animals 400, 000 or more.18 A typical mammal such as a mouse may harbor "only" 100,000 genes, a complement that is to be found in each and every one of its cells. As has been graphically expressed by Professor Edward 0. Wilson of Harvard University:19 "Each of the cells (Of the house mouse) contains four strings of DNA, each of which comprises about a billion nucleotide pain organized into a hundred thousand structural genes. If stretched out fully, the DNA would be roughly one yard long. But this molecule is invisible to the naked eye because it is only 20 angstroms in diameter. If we magnified it until its width equaled that of a wrapping string to make it plainly visible, the fully extended molecule would be 600 miles long. As we traveled along its length, we would encounter some 20 nucleotide pairs to the inch. The full information contained therein, if translated into ordinary-sized printed letters, would just about fill all 15 editions of the Encyclopedia Britannica published in 1768." Each species, then, constitutes its own stock of genetic diversity, and virtually all species harbor a far greater amount of genetic variability than is suggested by the concept of species alone. Not only does a species comprise a number of subspecies, races and populations, each of which constitutes a distinctive reservoir of genetic material. All the organisms that go to make up a species are genetically differentiated, due to the high levels of genetic polymorphism across many of the gene loci (except in cases of parthenogenesis and identical twinning).20 The 10,000 or so ant species that have been identified are estimated to comprise e 1015 individuals at any given moment.21 All the more, then, the total number of species is not the only standard by which we should evaluate the abundance and diversity of life. This means there is another dimension to the impoverishment that is overtaking Earth's biotas. Many species are losing whole sub-units, in the form of races and populations, at a rate that greatly reduces their genetic variability. Even though these species are not being endangered in terms of their overall numbers, they are suffering a critical decline in their genetic makeup. For example, the remaining gene pools of major crop plants such as corn and rice amount to only a fraction of the genetic diversity they harbored only a few decades ago, even though the species themselves are anything but threatened.
Let us now address the key question of how fast species are being eliminated. Extinction has been a fact of life virtually since life's first emergence. Of an estimated half billion species that have ever existed, the present few million are the modern-day survivors. Almost all past extinctions, however, have occurred by virtue of natural processes. Today by far the predominant influence in the situation is man, who eliminates whole habitats, complete communities of species, in super-short order. If we reckon that the average duration of a species is, roughly speaking, some five million years, and if we further reckon that there has been a crude average of 900,000 extinctions every one million years during the last 200 million years, then the average "background rate" of extinctions has been, as a very rough-and-ready estimate, one in every one and one-ninth years.22 The present human-caused rate is certainly hundreds of times higher, and could easily be one thousand times higher - possibly many More Still.23,24 We have no concise grasp of the rate of extinctions underway. The great majority of species in question are precisely those, such as insects and other arthropods in tropical forests, that are least documented. We know all too little about their very existence, let alone about their survival status. So we are far from having an exact picture of what is happening. To help us gain an insight into the situation, let us take a lengthy look at tropical forests. There is general agreement that these forests, while covering only 6 percent of Earth's land surface, contain at least 50 percent of all species, and conceivably 90 percent or even more.25 There is also general agreement that remaining primary forests cover rather less than 3.6 million square miles out of 6 million that once existed; that between 30,000 and 37,000 square miles are eliminated outright each year; and that at least a further 40, 000 square miles are grossly disrupted each year (these figures derive from a data base of the late 1970s; the rates have increased somewhat since then).26 This means, roughly speaking, that one percent of the biome is being deforested each year, and rather more than another one percent is being significantly degraded. By the end of the century there could be little left of the biome in primary status with full complement of species, outside of two large remnant blocs (one in the Zaire Basin and the other in the western half of Brazilian Amazonia), plus some outlier areas such as the Guyana tract of forest in northern South America and perhaps parts of New Guinea. Moreover, these relict sectors of the biome are little likely to survive beyond a few further decades, if only because of sheer expansion of impoverished throngs of forestland farmers. As a measure of what rapid population growth (immigration rather than natural increase, i.e., through the phenomenon of the shifted cultivator) can impose on tropical forests, consider the situation in Rondonia, a state in the southern sector of Brazilian Amazonia. Since 197 5 the population has grown from I 11, 000 to more than one million today, i.e. an almost 10-times increase in little over 10 years. In 1975 almost 500 square miles of forest were cleared. By 1982 this amount had grown to more than 4,000 square miles, and by early 1985 to almost 6,500.27 To help us gain a more precise insight into the scope and scale of present extinctions, let us look briefly at three particular areas, viz. the forested tracts of western Ecuador, Atlantic coast Brazil 1 and Madagascar. Each of these areas featured exceptional concentrations of species with high levels of endemism. Western Ecuador is reputed to have once contained between 8,000 and 10,000 plant species, with an endemism, rate somewhere between 40 and 60 percent.28 If we suppose, as we reasonably can by drawing on detailed inventories in sample plots, that there are between 10 and 30 animal species for every one plant species, the species complement in western Ecuador must have amounted to almost 200,000 in all. Since 1960 almost the entire forest cover of western Ecuador has been destroyed to make way for banana plantations, oil exploiters, and human settlements of various sorts. How many species have thus been eliminated is difficult to judge, but they must number at least in the tens of thousands - all eliminated in just 25 years. Similar baseline figures and a similar story of forest depletion, though for different reasons and over a longer time period, apply to the Atlantic-coastal forest of Brazil29 and to Madagascar.30 So in these three areas alone, with their 600,000 species, half of them endemics, the recent past must have witnessed a sizable fallout of species.31 In fact it is realistic to surmise that in these three areas alone the extinction rate could well have averaged several species a day since about 1950.
As for the future, the outlook seems all the more adverse, though its detailed dimensions are still less clear than those of the present.32 Despite the uncertainty, however, it is worthwhile to delineate the nature and compass of what lies ahead in order to grasp the scope of the extinction spasm that impends. Let us look again at tropical forests. We have already seen what is happening to three critical areas. We can identify a good number of other sectors of the biome that are similarly ultra-rich in species and that likewise face severe threat of destruction. They include the Mosquitia Forest of Central America; the Choco Forest of Colombia; the Napo center of diversity in Peruvian Amazonia (plus seven other centers out of 20-odd centers of diversity in Amazonia that lie around the fringes of the basin and hence are unusually threatened by settlement programs and various other forms of "development"); the Tai Forest of Ivory Coast; the montane forests of East Africa; the relict wet forest of Sri Lanka; the monsoon forests of the Himalayan foothills; northwestern Borneo; certain lowland areas of the Philippines; and several islands of the South Pacific (New Caledonia, for instance, with 6,530 square miles, or almost the size of New Jersey, contains 3,000 plant species, 80 percent of them endemic). These 20 sectors of the tropical forest biome amount to roughly 400,000 square miles (only two and a half times the size of California), or a mere one-tenth of remaining undisturbed forests. So far as we can best judge from their documented numbers of plant species,33 and by making substantiated assumptions about the numbers of associated animal species, we can reckon that these 20 areas surely harbor one million species (assuming a low planetary total of 5-7 million species). If present land-use patterns and exploitation trends persist, there will be little left of these forest tracts except in the form of degraded remnants by the end of this century or shortly thereafter. Thus deforestation in these areas alone could well eliminate very large numbers of species, surely hundreds of thousands, within the next 20 years at most.34 Looking at the situation another way, we can reckon on the basis of what we know about plant numbers and distribution, together with what we can surmise about their associated animal communities, that almost 20 percent of all species on Earth occur in forests of Latin America outside of Amazonia, and another 20 percent in forests of Asia and Africa outside the Zaire Basin.35 All of the forests in which these species occur may well disappear by the end of this century, or early in the next at the latest. If only half of the species in these forests disappear, this will amount to at least three-quarters of a million species. How about the prognosis for the longer-term future, to the effect that eventually we could lose at least one-quarter, possibly one-third, and conceivably a still larger share of all extant species? Let us take a quick look at the case of Amazonia.36 If deforestation continues at present rates (it is likely to accelerate) until the year 2000, but then were to halt completely, we should anticipate a loss of about 15 percent of plant species. The calculation behind this loss figure is entirely reasonable and documentable, based as it is on the well-established theory of island biogeography37 and abundant evidence of pervasive deforestation patterns in Amazonia. Were Amazonia's forest cover to be ultimately reduced to those areas now set aside as parks and reserves, we should anticipate that 66 percent of plant species would eventually disappear, together with almost 69 percent of bird species and similar proportions of all other major categories of species. Of course we may learn how to manipulate habitats to enhance survival prospects. We may learn how to propagate threatened species in captivity. We may be able to apply other emergent conservation techniques, all of which could help to relieve the adverse repercussions of broadscale deforestation. But in the main, the damage will have been done. For reasons of island biogeography and of "ecological equilibriation" (delayed fallout effects), some extinctions in Amazonia will not occur until well into the 22nd century, or even further into the future. So a major extinction spasm is Amazonia is entirely possible, indeed plausible if not probable.
Nor are protected areas likely to provide a sufficient answer, for reasons that go beyond island biogeography and incorporate a climatic dimension. In Amazonia, for instance, it is becoming apparent that if as much as one-half of the forest were to be safeguarded in some way or another (e.g., through multiple-use conservation units as well as protected areas), but the other half of the forest were to be "developed out of existence," there could soon be at work a hydrological feedback mechanism that would allow a good part of Amazonia's moisture to be lost to the ecosystem.38 The outcome for the remaining forest would be a steady desiccatory process, until the forest became more like a woodland - with all that would mean for the species communities that are adapted to forest habitats. Even with a set of forest safeguards of exemplary type and scope, Amazonia's biotas would be more threatened than ever. Still more widespread climatic changes, with yet more marked impact, are likely to emerge within the foreseeable future. By the first quarter of the next century we may well be experiencing the climatic dislocations of a planetary warming stemming from buildup up carbon dioxide39 and other "greenhouse gases" in the global atmosphere. The consequences for protected areas will be pervasive and profound. The present network of protected areas has been established in accordance with present-day needs. The current goal is to ensure that all biotic provinces, some 200 of them altogether, are represented. Many biomes still lack adequate representation. Indeed a consensus of professional opinion suggests that the total expanse of protected areas needs to be increased at least three times, or to about five million square miles, if it is to constitute a representative sample of Earth's ecosystems.40 Of tropical forests, at least 10 percent and possibly 20 percent should be protected, but to date well under 5 percent have been afforded protection of any sort - and of such parks as exist, a good number are "paper parks." But even if sufficient areas were to be set aside for protection of all wildlife communities and threatened species, their viability would soon be threatened as vegetation zones, in the wake of broadscale climatic change, start to "migrate" away from the Equator - with all manner of disruptive repercussions for natural environments. In short, the present global network of protected areas, even with additions, may prove incapable of meeting newly emergent needs, even as soon as the next few decades. Present-day planners of parks and reserves should urgently seek to adapt their policies and programs accordingly.41 Regrettably only one major body, the Conservation Foundation, is addressing the issue in substantive fashion. These, then, are some dimensions of the extinction spasm that we can reasonably assume will overtake the planet's biotas within the next few decades (unless of course we do a massively better job of conservation; see below). In effect we are conducting an irreversible experiment of global scale with the myriad array of species that we are fortunate to share the planet with-and we are I conducting our experiment with scarcely a thought for what we are doing.
We might be better inclined to give more thought to the issue if we were to consider some economic values at stake.42 For sure, there are all manner of other reasons why we should be concerned - more pertinent in principle, less productive in practice. Among these many other reasons there are the biological, ecological and genetic attributes of species, together with their aesthetic, cultural and ethical values, that will surely count more in the long run than those attributes that may well help the threatened-species cause in the immediate future.43 But the economic values inherent in species, especially in their genetic materials, provide an "instant rationale" that should help carry the day during the next few decades - particularly in the tropics, which, with at least two-thirds of all species and a still greater proportion of threatened species, is roughly coextensive with the Third World. Developing nations usually lack the conservation resources, that is the scientific skills, institutional capabilities and funds, to safeguard their species stocks. To the extent that species can be enabled to "pay their way in the marketplace," their prospects for survival are enhanced. From the morning cup of coffee to evening nightcap of drinking chocolate, we benefit at multiple points in our daily lifestyles from species and their genetic resources. Without knowing it, we utilize hundreds of products each day that owe their origin to wild plants and animals. Our daily bread, for instance. The corn and wheat crops of North America, like those of Europe and other major grain-growing regions, have been made bountiful principally through the efforts of crop breeders rather than through huge amounts of fertilizers and pesticides - and crop breeders are increasingly dependent on genetic materials from wild relatives of wheat and corn. In common with all agricultural crops, the productivity of modern corn and wheat is sustained through constant infusions of germplasm. Thanks to this regular "topping up" of the genetic constitution of the United States' main crops, the U.S. Department of Agriculture estimates that germplasm contributions lead to increases in productivity that average around one percent annually, with a farm-gate value well over $1 billion (1980 values).44 To this extent, then, we enjoy our daily bread by partial grace of the genetic variability that we find in wild relatives of modern crop plants. And "we" means each and every one of us. Whether we realize it or not, we enjoy the exceptional productivity of modern corn each time we read a magazine. Since cornstarch is used in the manufacture of sizing for paper, the reader of this paper is enjoying corn by virtue of the "finish" of the page he or she is looking at right now. The same cornstarch contributes to our lifestyles each time we put on a shirt or blouse. Cornstarch likewise contributes to glue, so we benefit from corn each time we mail a letter. And the same applies, through different applications of corn products, whenever we wash our face, apply cosmetics, take aspirin or penicillin, chew gum, eat ice cream (or jams, jellies, catsup, pie fillings, salad dressings, marshmallows, or chocolates), and whenever we take a photograph, draw with crayons, or utilize explosives. Corn products also turn up in the manufacture of tires, in the moulding of plastics, in drilling for oil, in the electroplating of iron, and in the preservation of human blood plasma. Hence the value of the wild corn recently discovered in a montane forest of south-central Mexico.45 This plant is the most primitive known relative of modern corn; at the time of its discovery it was surviving in only three tiny patches covering a mere 10 acres - a habitat that was threatened with imminent destruction by squatter cultivators and commercial loggers. The wild species turns out to be a perennial, unlike all other forms of corn which are annuals. Now that it has been cross-bred with established commercial varieties of corn, it opens up the prospect that corn growers could be spared the seasonal expense of ploughing and sowing, since the plant would spring up again of its own accord like grass or daffodils. Even more important, the wild corn offers resistance to at least four of eight major viruses and mycoplasmas that have hitherto baffled corn breeders.46 These four diseases cause at least a one-percent loss to the world's corn harvest each year, worth more than $500 million. Equally to the point, the wild corn, discovered at elevations between 7,500 and 10,000 feet, is adapted to habitats that are cooler and damper than established cornlands. This offers scope to expand the cultivation range of corn by as much as one--tenth. All in all, the genetic benefits supplied by this wild plant, surviving in the form of no more than a few thousand last stalks, could total several billion dollars per year.47 Wild species likewise contribute to our health needs. Each time we take a prescription from our doctor to the neighborhood pharmacy there is one chance in two that our purchase - whether an antibiotic, tranquilizer, diuretic, laxative, or contraceptive pill - owes its origin to startpoint materials from wild organisms.48 The commercial value of these medicines and drugs in the United States now amounts to some $ 14 billion a year.49 If We extend the arithmetic to all nations, and include nonprescription materials plus pharmaceuticals, the commercial value tops $40 billion a year. As a specific example of a plant source of drugs, let us note the rosy periwinkle, a plant originally from Madagascar's forests. The periwinkle habors alkaloids that yield two potent therapies against Hodgkin's disease, leukemia and other blood cancers. Commercial sales of the two drugs now total more than $150 million per year. When we assess the economic benefits too, viz. workers' productivity time saved and the like, we find the value to American society alone can be estimated at more than $300 million per year. According to the National Cancer Institute,50 there could well be another five plants in Amazonia alone with capacity to generate superstar drugs against cancer. This clarifies for us the data presented above on projected plant extinctions in Amazonia. Let us recall that Madagascar's forests, the periwinkle's native habitat, are now 93 percent destroyed, with over half their species presumed lost or about to be lost. We also derive many industrial benefits from wildlife.51 Plants and animals already serve the needs of the butcher, the baker, the candlestick maker, and many others. As technology advances in a world growing short of many things except shortages, industry's needs for new raw materials expands with every passing day. Wildlife-derived materials contribute by way of gums and exudates, essential oils and ethereal oils, resins and oleoresins, dyes, tannins, vegetable fats and waxes, insecticides, and multitudes of other biodynamic compounds. Many wild plants bear oil-rich seeds with potential for the manufacture of fibers, detergents, starch, and eral edibles - even for an improved form of golf ball. Still more important, a few plant species contain hydrocarbons rather than carbohydrates, and as we all know, hydrocarbons are what make petroleum petroleum.52 A number of wild plant species appear to be candidates for "petroleum plantations." As luck would have it, certain of these plants can flourish in areas that have been rendered useless through, for example, strip-mining. Hence we have the prospect that land that has been degraded by extraction of hydrocarbons from beneath the surface could be rehabilitated by growing hydrocarbons above the surface. Moreover, a petroleum plantation need never run dry as an oil well does. We enjoy these myriad products after scientists have underi taken only a superficial examination of the genetic resources available to us from wild species. In fact, scientists have taken a look at only 10 percent of all plant species, and they have taken a close look at only one percent. Well might we assert, then, that Earth's stock of species, with the genetic materials they harbor, represent some of the most valuable raw materials with which we can confront the unknown challenges of the future. Fortunately we can look forward to expanding our use of wild genetic resources, thanks to the burgeoning industry of bioengineering and its associated technologies. Genes are the hereditary materials of each species' makeup; we can isolate and manipulate them. So the emergent field of bioengineering places a premium on a broad array of genetic variability. This throws new light on the phenomenon of extinction, which, to cite Professor Tom Eisner of Cornell University,53 "no longer means the simple loss of one volume from the library of nature. It means the loss of a loose-leaf book whose individual pages, were the species to survive, would remain available in perpetuity for selective transfer and improvement of other species." Thanks to bioengineering it is becoming plain that in the field of agriculture the Green Revolution is being superceded by a still more revolutionary phenomenon, the Gene Revolution. This is a breakthrough in agricultural technology that may soon enable us to harvest crops from deserts, farm tomatoes in seawater, grow super-potatoes in many localities that have hitherto remained off limits, and enjoy entirely new crops such as a "pomato." In fact the sophisticated techniques of genetic engineering may even be bringing us closer to the day when we can send many more people to bed with a full stomach. A similar prospect applies with respect to medicine, where we can look forward to one advance after another to match the discovery of penicillin. Medical pioneers foresee more innovative advances during the last two decades of this century than during the previous two centuries. As for industry, our creative applications of the gene reservoirs of wild species may soon make our present industrial scene appear like a hangover from the Stone Age. In short, we may steadily find ourselves becoming more prosperous in our daily welfare, more sophisticated in our technological know-how, and more sensitive in our use of Earth's renewable resources, by virtue of a new "discover nature" movement.
But the foreseeable fallout of species within the next few decades is far from the entire story. A longer term, and ultimately more serious repercussion could lie with a disruption to the course of evolution, insofar as speciation processes will have to work with a greatly reduced pool of species. We are probably being optimistic, moreover, when we call it a disruption. A more likely outcome is that certain evolutionary processes will be suspended or even terminated. The forces of natural selection can work only with the "resource base" available.54 If that base is drastically reduced, the result could be disruption of the creative capabilities of evolution, persisting far into the future. To cite the graphic phrasing of Soule and Wilcox,55 "Death is one thing; an end to birth is something else." From what little we can discern from the geologic record, the "bounce-back" time may require millions of years. After the dinosaur crash, for instance, between 50,000 and 100,000 years elapsed before there started to emerge a set of diversified and specialized biotas; a further 5 to 10 million years went by before there were bats in the skies and whales in the seas. Following the crash during the late Permian when marine invertebrates lost about half their families, it took as much as 20 million years before the survivors could establish even half as many families as they had lost. But the evolutionary outcome this time around could prove yet more drastic. The critical factor lies with the likely loss of key environments. Not only do we appear set to lose most if not virtually all of the tropical forest biome. There is progressive depletion of tropical coral reefs, wetlands, estuaries, and other biotopes with exceptional abundance and diversity of species and with unusual complexity of ecological workings. These environments have served in the past as preeminent "powerhouses" of evolution, meaning that they have thrown up more species than other environments. It has long been thought56 that virtually every major group of vertebrates and many other large categories of animals originated in spacious zones with warm, equable climates, notably the Old World tropics, and especially their forests. It has likewise been supposed that the rate of evolutionary diversification - whether through proliferation of species or through emergence of major new adaptations - has been greatest in the tropics, especially in tropical forests.57 In addition, tropical species, especially tropical forest species, appear to persist for only brief periods of geological time, which implies a high rate of evolution. Of course tropical forests have been severely depleted in the past. During drier phases of the late Pleistocene they have been repeatedly reduced to only a small fraction, occasionally as little as one-tenth, of their former expanse. Moreover tropical biotas seem to have been unduly prone to extinction.58 But the remnant forest "refugia" usually contained sufficient stocks of surviving species to recolonize suitable territories when moister conditions returned.59 Within the foreseeable future, by contrast, it seems all too possible that most tropical forests will be reduced to much less than one-tenth of their former expanse, and their pockets of "holdout species" will be so much less stocked with potential colonizers. Furthermore, the species depletion will surely apply across most if not all major categories of species. This is almost axiomatic if extensive environments are eliminated wholesale. So the result will contrast sharply with the end of the Cretaceous, when not only placental mammals survived (leading to the adaptive radiation of mammals, eventually including man), but also birds, amphibians, and crocodiles and many other nondinosaurian reptiles. In addition the present extinction spasm looks likely to eliminate a sizable share of terrestrial plant species, at least one-fifth within the next half century and a good many more within the following half century. During most mass-extinction episodes of the prehistoric past, by contrast, terrestrial plants have survived with relatively few losses.60 They have thus supplied a resource base on which evolutionary processes could start to generate replacement animal species forthwith. If this biotic substrate is markedly depleted within the foreseeable future, the restorative capacities of evolution will be diminished all the more. At the same time of course, a mega-extinction episode could trigger an outburst of speciation in some categories of species. A certain amount of "creative disruption," in the form of, e.g., habitat fragmentation, can readily lead to splitting off of populations, followed by differentiation and termination of inter-breeding, so that a population becomes distinctive enough to rank as a new race, then a subspecies, finally a species. Equally important, mass extinction leaves a multitude of niches vacant, allowing a few species to expand and then to diversify. Through these forms of creative disruption, we can discern incipient speciation in, for instance, the house sparrow and the coyote in the United States, both of which have developed several distinctive races, even subspecies. But a marked acceleration of speciation through these processes will not remotely match the scale of extinctions. Whereas extinction can occur in just a few decades, and sometimes in a mere year or so (a valley in a tropical forest with a pocket of endemic invertebrates can be converted into pastureland within a single season), the time required to produce a new species is much longer. It takes decades for outstandingly capable contenders such as certain insects, centuries if not millennia for many other invertebrates, and hundreds of thousands or even millions of years for most mammals. Among the reduced stock of species that survives the present extinction episode will surely be a disproportionate number of opportunistic species. These species rapidly exploit newly vacant niches (by making widespread use of food resources), are generally short-lived (with brief gaps between generations), feature high rates of population increase, and are adaptable to a wide range of environments. All of these traits enable them to exploit new environments and to make excellent use of "boom periods" - precisely the attributes that enable opportunistic species to prosper in a human-disrupted world. Examples include the house sparrow, the European starling, the housefly, the rabbit, and the rat, plus, many other pest species, together with many "weedy" plants. Not only are they harmful to humans' material needs, but they foster a homogenization of biotas by squeezing out less adaptable species. The house sparrow in North America is usurping the niches of bluebirds, wrens and swallows, while the herring gull in northwestern Europe is adversely affecting the rarer terns. While generalist species are profiting from the coming crash, specialist species, notably predators and parasites, will probably suffer disproportionately higher losses. This is because their lifestyles are often more refined than the generalists', and their numbers are usually much smaller anyway. Since the specialists are often the creatures that keep down the populations of generalists, there" may be little to hold the pests in check. Today probably less than five percent of all insect species deserve to be called pests. But if extinction patterns tend to favor clever species, the upshot could soon be a situation where these species increase until their natural enemies can no longer control them. In short, our descendants could shortly find themselves living in a world with a "pest and weed" ecology. These, then, are some of the issues for us to bear in mind as we begin to impose a fundamental shift on evolution's course. The, biggest factor by far is that as we proceed on our impoverishing way, we give scarcely a moment's thought to what we are doing. If we were to ponder it a bit more, would this be truly what we want? Unfortunately we are "deciding " without even the most superficial reflection - deciding all too unwittingly, yet effectively and increasingly. The impending upheaval in evolution's course could rank as one of the greatest biological revolutions of paleontological time. In scale and significance, it could equal the development of aerobic respiration, the emergence of flowering plants, and the arrival of limbed animals. But whereas these three departures if life's course rank as advances, the prospective depletion of many evolutionary capacities will rank as a distinctive setback. In short, the future of evolution should be regarded as one of the most challenging problems that humankind has ever encountered. After all, we are the first species ever to be able to look out upon the biosphere and to decide whether we would remake part of it - to consciously determine the future course of evolution.
There are many conservation initiatives available to us. Here we shall concentrate on just a couple, these being central to future conservation strategies, yet receiving all too little attention. 1. A Triage Strategy for Threatened Species Given the scale of the extinction problem, we cannot possibly help all species at risk. We have limited resources at our disposal, in the form of finance, scientific skills and the like. Even if these resources were to be increased several times over, we could not hope to save more than a proportion of all species that appear doomed to disappear. The processes of habitat disruption have developed too much momentum to be halted in short order. So when we allocate funds to safeguard one species, we automatically deny those funds to other species. This means that we perforce allocate our conservation resources, and thereby assign priority to certain species in preference to others. We choose unconsciously rather than deliberately. But we choose. Already we support only a small fraction of all species at risk. We shall soon find ourselves in a situation where we can assist still fewer in relation to overall needs - and thereby we shall willy-nilly be placing a still greater premium on some species rather than others. This raises a key question. How are we to allocate our scarce conservation resources in a most efficient fashion in order to safeguard the "most deserving" species? In the view of some observers, we have already reached a stage where there is merit in determining which species are most worthy of a continued place on the planet. Agonizing as it will be to make such choices, we need to make our conservation strategy as logically selective as possible. In other words, our erstwhile approach needs to be made more systematic if we are to get the best return on each scarce conservation dollar invested. Hitherto, and for lack of clearer insight, we have been obliged to make our choices haphazardly rather than methodically. We have tended to support those species that receive the most public attention. As a result, we focus on species that are well known to science, that are recognized as threatened, and that generally offer some measure of popular appeal. By contrast, species with a less glamorous image, such as creepy-crawly insects and prickly plants, receive far less attention. Species that have not yet been documented in detail by science and whose survival prospects are therefore a mystery receive all too little attention, even though they comprise the great bulk of all species. Thus present conservation strategies imply, albeit without deliberate intent, that the vast majority of Earth's species are insufficiently worthy of safeguard efforts. Yet it is among the "unconsidered majority" that most extinctions are now occurring. This is not to deny of course that all species possess an equal right to exist in principle,61 and that they should be enabled to enjoy that right in practice. But in the world as it works - a world that does not always recognize ethical imperatives - conservationists increasingly have to make choices, unusually tough choices at that. How, then, shall we best choose? We could make a start through systematic analysis of biological factors, such as those that make some species more susceptible to extinction than others; for example, sensitivity to habitat disruption, or poor reproductive capacity. Then we could move on to consider ecological factors; for example, do some species, or categories of species, contribute more to their ecosystems than others? Plus genetic attributes; for example, which species, or categories of species, reveal greatest genetic variability? Having covered the life-sciences aspects, we could evaluate social-sciences aspects-economic, political, legal and socio-cultural concerns. When we integrate all the various factors that tell for and against a species, or a category of species, we shall have a clearer idea of where we can best apply our conservation muscle.62 This priority-ranking approach, sometimes known as a triage strategy (from the French word "trier," to sort), is exploratory in both scope and intention. Far from seeking to establish quantification of all critical parameters, it tries to touch base with all relevant sets of values in order to illuminate an unduly confused situation. It is orderly rather than haphazard, and it enables conservationists to make more productive use of their limited finances and skills, How would triage work out in a specific instance? With regard to the California condor, we need to ask not only whether X million dollars will give the bird a Y-percent chance of survival. We must also ask whether the same funds could be better spent on other species in trouble.63 They could be used to assist dozens of other U.S. species; e.g., freshwater mollusks (half of which are threatened), with a 90 percent chance of success. If the sum were applied in tropical forests it could help hundreds if not thousands of species with a 100 percent chance of success (for the time being, at any rate). But of course these other species do not enjoy a fraction of the charisma of the condor. To the extent that public opinion is a predominant factor in conservation planning, a democratic society must take cognizance of it. What we need, then, is broadscale discussion of whether the funds are best spent on the condor. Yet in all the debate that has raged on the condor question there has been next to no analysis of whether we could not spend the funds better elsewhere. Triage means that many hard, even harsh decisions will have to be made. Nobody cares for the prospect of consigning certain species to oblivion - though that would not be done deliberately. Rather it would be the result of using conservation resources to best advantage. In any case, we are already consigning species to oblivion in appalling numbers. So we might as well do the job with as much selective discretion as we can muster. In other words, we should make our choices among species explicitly rather than implicitly; we should determine the future of species by design rather than by default. Furthermore, the triage concept can be applied at ecosystem level. Plainly certain ecological zones are biotically richer than others. By safeguarding sectors of these zones, conservationists accomplish more in terms of saving total numbers of species than through safeguarding much larger zones in biotically depauperate zones. As we have noted, this consideration applies especially to tropical forests, a zone that should receive top ranking on any conservationist's list of priorities on the grounds that the forests offer best return per scarce conservation dollar invested. To this extent conservationists can finesse the dilemmas of species ranking by directing greater attention to protection of entire communities of species, indeed to the protection of entire ecosystems. True, this expanded approach is already proclaimed by conservationists. But all too often it is observed more in principle than in practice, since the bulk of efforts still tend to be directed at individual species rather than communities or ecosystems. Yet when we pitch our response at the broader-scope level of communities and ecosystems we are still faced with agonizing choices. How do we choose between those communities and ecosystems where rescue operations would be very appropriate, highly helpful or super-important, and those where they are simply essential, given that we cannot afford to rescue the whole lot? How should we rank, say, patches of tropical forests, coral reefs and wetlands in order of priority? A difficult decision indeed. Of course the choice need not necessarily be broached in this perplexing form. Were all conservation resources to be directed at these three ecological zones alone, on the grounds that they constitute clear priorities ahead of the rest of the field, we would probably not have to make choices between them, since our resources would then be sufficient to do a much better job on each of the three categories. Alas, that is not the way the world works, and the great bulk of conservation funds originating mainly in rich nations of the temperate zones continues to be spent on near-to-home needs, to the detriment of far greater needs in the tropics. Above all, let us remember that ever since the start of the save-species movement we have been making choices between species, The expanded strategy proposed here amounts to nothing new. Rather, it proposes a more methodical approach to the selection process. The question is not, "Shall we, now attempt to apply triage?" It is "How shall we apply triage to better advantage?" 2. Shift in Research Emphasis While waiting for more funds to become available there is much we could do through greater research emphasis on some key questions - and these comments are directed specifically toward academic institutions such as the University of California at Berkeley. Many of the fundamental issues remain virtually unaddressed. Yet in 50 years' time, and supposing that not enough is done to stem the attrition of species, will academics not ask why, in the mid-1980s when we knew what was going on, we did not leap to plug some of the major research gaps? And will we then respond that we had other priorities, such as the 10, 00 1st piece of research on the white-tailed deer, this being a species that, far from being threatened, flourishes like a weed, and on which at least $ 10 million of research funds have already been spent since 1950?64 Thus the problem is not only an outright shortage of funds. So what else is missing? Well, let us reflect again that we inhabit the biosphere at a time when it is undergoing perhaps its most traumatic upheaval in all its four billion years. This is not only a fearful time, it is an exhilarating time. If Charles Darwin could have chosen any other era to live, surely he would choose the present one as a time when we are undertaking a biological experiment of uniquely grand scale and profound repercussions, and with uniquely abundant scope for pioneering research. And if Darwin were alive today, would he not head straight for the tropics (regardless of those famous logistical problems - there were plenty of those in 1850), as the place to grapple with leading biological questions and as the place to make the biggest research breakthroughs fastest? Would he not, for instance, make for Lake Malawi, which as we have seen, is a veritable cauldron of evolutionary activity, yet virtually untouched in terms of substantive scientific research? Or would he not go off to the eastern slopes of the Andes where he would find, in just the 6,000-square mile Manu Park, at least 200 mammal species (more than in the United States and Canada), 900 bird species (more than one in ten of all on Earth), and 8,000 plant species (almost half as many as in the 500-times-larger Australia)? Or might he prefer the Panamanian isthmus, where the recently divided marine communities offer scope for evolutionary studies of a quantity and quality that far surpass whatever was on offer in the Galapagos Islands? Or would he prefer to tackle Tsavo Park in Kenya, or one of the other Vermont-sized parks in savannah Africa where formerly abundant elephant numbers have recently crashed because of drought and ivory poaching, whereupon the vegetation communities are bouncing back with remarkable vigor and variety - a superscale exercise in plant-animal relations that in terms of the exceptionally dynamic interactions involved, plus the telescoped intensity of the process, must be all but unprecedented in modem biology? This is surely a phenomenon so exceptional that in many respects it would be exceeded only by the appearance in these elephant lands of a mammoth. Yet it is a phenomenon largely unrecorded and unregretted by the scientific community. What research topics, apart from the items indicated above, deserve urgent attention with respect to the anticipated mass-extinction event? Herewith a few candidate themes by way of illustration, these being items that have not received nearly enough attention to date. 1. Differentiated fallout rates: Between biomes and regions and between species at various taxonomic levels, also between clades (monophyletic evolutionary lineages). 2. Linked extinctions: What prospect is there that a mass-extinction process will feed on itself through mechanisms that, by virtue of the integrative workings of ecosystems (especially of the more species-rich and complex ecosystems of the tropics), can trigger a domino effect of extinctions, can even precipitate "cascades of extinctions"?65 3. Diversity and integrity of nature: In light of the possible threat of linked extinctions on large scale, should we consider a switch in our conservationist emphasis, from seeking to safeguard the diversity of nature to trying instead to preserve the integrity of nature?66 Can we always be so sure that an optimum number of species must necessarily be the same as a maximum number of species? 4. Insights from the past: What can the past tell us about the future, both the immediate and the longer-term future? At times of mass extinction in the prehistoric past, traits such as broad geographic range of constituent species and high species richness do not appear to have been of much help to communities. Conversely, traits such as broad geographic deployment of entire lineages have served to enhance survival rates.67 In addition, endemics have been hit even harder than might have been expected. 5. Recovery period: What does the past reveal about the potential bounce-back time required in the wake of the present mass-extinction event, before evolutionary processes come up with an abundance and variety of species to match those of today? How far will there be an "end to birth" hiatus? 6. Survivors of mass extinctions: As well as telling us much about the victims of mass-extinction events, what does the past tell us about the survivors? With a better grasp of the biological, ecological and geographical attributes that enable taxa to survive phases of biotic crisis, we may gain a clearer insight into the community makeup of biotas that are likely to come through the present extinction episode. In addition, it might throw light on the question of differentiated fallout rates for K- and r-selected species, with ecological repercussions in terms of a putative "pest and weed" aftermath. 7. Conservation in practice: What save-species-management techniques may become available to us, while little investigated to date, such as man-directed species packing? What scope is there for manipulation of gene pools in order to maintain minimum viability? What other innovative tactics deserve urgent investigation? 8. The greenhouse effect and other climatic dislocations: In the light of their critical consequences for protected-area strategies, what responses should we eventually consider in the form of, e.g., exceptional adaptiveness in wildland management? 9. The question of a triage strategy: How valid is it in principle, how applicable in practice? What criteria shall we invoke, what parameters shall we seek to quantify? 10. The economics of threatened species: Virtually virgin territory, yet critical to the rational planning of future conservation strategies. What are species worth to us, now and into the indefinite future? What are we willing, and what should we be willing, to pay to preserve species? Often enough the cost-benefit ratio of save-species efforts are highly positive, though this is rarely articulated in practice and hence rarely taken into account.68 Economists might also look more at risk-reduction analysis, especially in those many circumstances where it is impossible to quantify benefits, whereupon it can be useful to apply an "insurance premium" approach. That is, to ask how much it will cost to build a safety net under the threatened species in question and then to assess whether the cost is socially acceptable. When these various items receive the attention they urgently warrant, we shall be well on the way to developing a new discipline - that of conservation biology - with the predictive capacity that characterizes a coherent field of science.70
In face of a bleak situation there are signs - a few signs, no more and no less - that this long-asleep issue is awakening. At last, at long glorious last. While the extinction threats have been growing larger faster, so too has public awareness been growing apace around the world. Mass extinction of species is no longer seen as a preoccupation of cutesy-creature enthusiasts and eco-freaks. It is starting to be perceived as a phenomenon that carries pragmatic implications for all citizens around the world, now and for generations to come. A few examples illustrate the outburst of public awareness. In Kenya the wildlife clubs have gone from strength to strength since their startup in the late 1960s, until the network of school clubs now totals more than 1,300, with around 70,000 members. In Indonesia there are some 400 conservation groups of one sort or another. They have banded together under the banner of the Indonesian Environmental Forum until they exert sizable political leverage with the Minister for Environment, Dr. Emil Salim (a Berkeley graduate), even with President Soeharto. In the United States membership of the World Wildlife Fund has expanded from 58,000 in 1981 to 172,000 in 1985, while annual donations have soared from under $4 million to almost $14 million. In response to this broad-scale grass-roots interest, governments have been moving to help their threatened species. They have been doing so primarily through additional protected areas. Today the worldwide network totals more than 1.6 million square miles, roughly equivalent to the United States east of the Mississippi. Since 1970 the network has expanded in extent by more than 80 percent, around two-thirds of which has occurred in the Third World. It is the new-found interest of governments that is especially encouraging - notably on the part of the government of the United States. In 1980 Secretary of State Edmund Muskie asserted that the question of genetic resources, among other environmental issues, was becoming a matter of national security for the United States.71 In 1981 the State Department convened an International Strategy Conference on Biological Diversity (meaning biological depletion). In 1983 Congress passed the International Environment Protection Act, which requires the government, through its foreign aid programs among other activities, to take special account of species communities and gene reservoirs around the world. Congress continues to pursue the issue through further legislative measures. By comparison with the needs of the situation, this can all be viewed as far too little and far too late. But it is a start - or at least a start on a start - toward recognizing one of the great steeper issues of our time, and seeing it in its proper scope. There is the first glimmering of an idea among the public at large that we are becoming unwitting witnesses of the greatest enduring intrusion we can make in our biosphere, short of all-out nuclear war followed by all-out nuclear winter - and whereas nuclear war still remains only a possibility, mass extinction is fast becoming a fact. Of all the environmental assaults we are imposing on the Earth, mass extinction will amount to the most pervasive and profound, and by far the most persistent. After all, it is intrinsically irreversible, which puts it in a class apart from deforestation, desertification and other environmental assaults. True, we shall need awhile to regenerate tropical f6rests - supposing we ever want to give it a try - probably hundreds of years, possibly thousands of years before they are restored to full vitality. But a mass-extinction episode of the sort now underway will not be made good for millions of years, perhaps tens of millions. Furthermore, until very recently, we have remained more indifferent to mass extinction than to any other environmental assault. All the more, then, we can now take credit for starting on a response to the situation. If the prospect of a suitable-size response seems daunting, we should remind ourselves that the first great waves of extinctions are only beginning to wash over the Earth's biotas. There is nothing inevitable about a mass extinction ahead of us. We can still save species, and save them in immense numbers. This is much more than has ever been available to any other community. Hitherto it has been something of a cachet for a biologist to have a newly-discovered species named after him. The time may soon arrive when the latter-day biologist can go one far better. He can have a species named after him by virtue of his having saved it from oblivion - indeed the same, readily enough, for large numbers of species. Should we not consider ourselves fortunate that we, alone among generations, are being given the chance to support the right to life of a large share of our fellow species - even to safeguard the creative capacities of evolution itself? This generation is confronted with an exceptional challenge, the challenge of saving species in their millions. Ours is the sole generation to be so favored. No generation in the past has faced the prospect of mass extinction within its lifetime; the problem has never existed before. No generation in the future will ever face a similar challenge: if this present generation fails to get to grips with the task, the damage will have been done and there will be no "second try". So should we not count ourselves privileged that we are afforded the opportunity to safeguard species in their millions? If we get on with the job, will not people in the future - for many generations into the distant future - look upon us as giants of the human condition? Will they not say of us that we recognized the scale of the challenge, that we saw it not only as a problem but also as an opportunity, and that we measured up to the task in a way that must have made us feel ten feet tall? What a time to be alive! back to top
2 W Rauh, 1979, Problems of Biological Conservation in Madagascar, in D. Bramwell, editor, Plants and Islands: 405-421, Academic Press, London, U. K. 3 A. Rodriguez, 1981, Marine and Coastal Environmental Stress in the Wider Caribbean Region, Ambio 10: 283-294. 4 B. Komarov, 1980, The Destruction of Nature in the Soviet Union, Sharpe Publishers, White Plains, N.Y; and P.R. Pryde, 1983, The Decade of the Environment in the U.S.S.R., Science 220: 274-279. 5 A.V. Hall, B. de Winter, S.F. Fourie and T.H. Arnold, 1984, Threatened Plants in Southern Africa, Biological Conservation 28: 5-20. 6 D.A. Scott and M. Carbonell, 1985, A Directory of Neotropical Wetlands, IUCN, Gland, Switzerland. 7 See also P.R., Ehrlich and A.H. Ehrlich, 1982, Extinction, Random House, New York; N. Myers, 1979, The Sinking Ark, Pergamon Press, Elmsford, New York; and N. Myers, 1985, Tropical Deforestation and Species Extinctions: The Latest News, Futures 17: 451-463. 8 A.W Gentry, 1986, Endemism in Tropical Versus Temperate Plant Communities, in: M.E. Soule, editor, Conservation Biology: Science of Scarcity and Diversity: 153-181, Sinauer Associates, Sunderland, Mass. 9 C.D.N. Bawl and 12 others, 1985, Destruction of Fisheries in Africa's Lakes, Nature 315: 19-20; and G.C. Coulter, et al., 1986, Special Features of the African Great Lakes and Their Susceptibility to the Effects of Human Activities, Bulletin of J.C.B. Smith Institute of lctheology, Grahamstown, South Africa. 10 W. Alvarez and five others, 1984, Impact Theory of Mass Extinctions and the Invertebrate Fossil Record, Science 223: 1135-1141. 11 For further discussion, see E. Mayr, 1982, The Growth of Biological Thought: Diversity, Evolution and Inheritance, Harvard University Press, Cambridge, Mass. 12 For some analysis and assessment of this point, see P.R. Ehrlich, 1986, The Machinery of Nature, Simon and Schuster, New York. 13 E. Mayr, 1982, see footnote 11 above. 14 For a stimulating review of this subject and related topics, see G.A. Bartholomew, 1986, The Role of Natural History in Contemporary Biology, BioScience 36: 324-329. For a more general appraisal, see G.L. Stebbins, 1977, Processes of Organic Evolution, third edition, Prentice-Hall, Englewood Cliffs, New Jersey. 15 J.M. Diamond, 1985, How Many Unknown Species Are Yet to be Discovered? Nature 315: 538-539; P.R. Ehrlich, 1986, see footnote 12 above; and E.O. Wilson, 1985, The Biological Diversity Crisis, BioScience 35: 700-706. 16 The worldwide total of taxonomists and systematists is actually declining. There are probably no more than 1500 professionals who are competent to deal with tropical organisms; and there are exactly two persons qualified to deal with termites, which are among the principal insect pests and soil movers of the world (E. 0. Wilson, 1985, see footnote 15 above). In a broader context of professional expertise, we may note that Colombia, with 25,000 plant species, has fewer than one dozen trained botanists, while Great Britain, with much less than one-tenth as many plant species, has more botanists than plant species for them to look at. 17 For some excellent broad-ranging treatment of the topic, see O.H. Frankel and M.E. Soule, 1981, Conservation and Evolution, Cambridge University Press, Cambridge, U.K.; and C. M. Schonewald-Cox and three others, editors, 1983, Genetics and Conservation, Benjamin/Cummings Publishing Company Inc., Menlo Park, Calif. 18 R. Hinegardner, 1976, Evolution of Genome Size, in F.J. Ayala, editor, Molecular Evolution: 179 - 199, Sinauer Associates, Sunderland, Mass. 19 E.O. Wilson, 1985, The Biological Diversity Crisis: A Challenge to Science, Issues in Science and Technology 2: 20 -25. 20 R.K. Selander, 1976, Genic Variation in Natural Populations, in F.J. Ayala, editor, Molecular Evolution: 21- 45, Sinauer Associates, Sunderland, Mass. 21 E. 0. Wilson, 1971, The Insect Societies, Harvard University Press, Cambridge, Mass. 22 D.M. Raup and J.J. Sepkoski, 1985, Periodicity of Extinctions in the Geologic Past, Proceedings of National Academy of Sciences U.S.A. 81: 801-805. See also D.M. Raup and J.J. Sepkoski, 1986, Periodic Extinction of Families and Genera, Science 231: 833-836. 23 P.R. Ehrlich and A.H. Ehrlich, 1982, see footnote 7 above; N. Myers, 1979, see footnote 7 above; N. Myers, 1984, The Primary Seam, W.W. Norton, New York; N. Myers, 1985, see footnote 7 above; and E.O. Wilson, 1985, see footnote 15 above. 24 Some observers believe that we can get a better idea of the "big picture" of the extinction rates if we look at families rather than species. According to the geologic record, the average "background rate" of extinctions has ranged between 2 and 4.6 animal families per one million years, a figure that can rise to an average of 19.3 families during a period of mass extinctions (D.M. Raup and J.J. Sepkoskj, 1985, see footnote 22 above). By contrast, during the foreseeable future we could well witness the demise of a sizable share of all families that number several thousands (a precise acceptable total is difficult to determine, due to differences of definition). This could conceivably work out at a crude average of tens of families per decade. 25 T.L. Erwin, 1983, Tropical Forest Canopies: The Last Biotic Frontier, Bulletin of the Entomological Society of America 29(1): 14-19. 26 Food and Agriculture Organization and United Nations Environment Program, 1982, Tropical Forest Resources, Food and Agriculture Organization, Rome, Italy, and United Nations Environment Program, Nairobi, Kenya; M. Hadley and J.P. Lanly, 1982, Tropical Forest Ecosystems: Identifying Differences, Seeing Similarities, Nature and Resources 19(1): 2-19; J. M. Melillo, et al., 1985, A Comparison of Recent Estimates of Disturbance in Tropical Forests, Environmental Conservation 12: 37- 40; N. Myers, 1980, Conversion of Tropical Moist Forests (report to National Academy of Sciences), National Research Council, Washington D.C.; J. Molofsky C.A.S. Hall and N. Myers, 1986, A Comparison of Tropical Forest Surveys, Carbon Dioxide Program, Department of Energy, Washington D.C.; and see N. Myers, 1984, footnote 23 above. 27 P.M. Fearnside and G. de L. Ferreira, 1984, Roads in Rondonia, Environmental Conservation 11: 358-360; C.J. Tucker, B.N. Holbern and T.E. Goff, 1984, Intensive Forest Clearing in Rondonia, Brazil, as Detected by Satellite Remote Sensing, Remote Sensing of the Environment 15: 255-261; and J. Wilson, 1985, Colonization in Rondonia: The Case of Ariquemis, doctoral dissertation, University of Florida, Gainesville, Florida. 28 A.H. Gentry, 1982, Patterns of Neotropical Plant Species Diversity, Evolutionary Biology 15: 1-84. 29 S.A. Mori, B.M. Bloom and G.T. Prance, 1981, Distribution Patterns and Conservation of Eastern Brazilian Coastal Forest Tree Species, Brittonia 33(2): 233-245. 30 W. Rauh, 1979, see footnote 2 above. 31 N. Myers, 1985, see footnote 7 above; P.H. Raven, 1985, Statement from Meeting of IUCN/WWF Plant Advisory Group, Las Palmas, Canary Islands, 24th 25th November, 1985, IUCN, Gland, Switzerland, and Missouri Botanical Garden, St. Louis, Missouri. 32 For some preliminary exploration of this theme, see N. Myers, 1985, The End of the Lines, Natural History 94: 2-6. 33 Conservation Monitoring Centre, 1986, Plants in Danger, Conservation Monitoring Centre (under IUCN), Cambridge, U.K. 34 N. Myers, 1986, Tropical Forests: Areas Ultra-Rich in Species, Ultra-Threatened with Conversion, (in prep). 35 P.H. Raven, 1985, see footnote 31 above. 36 D. Simberloff, 1986, Are We On the Verge of a Mass Extinction in Tropical Rain Forests?, in D.K. Elliott, editor, Dynamics of Extinction: 165-180, Wiley, New York. 37 For some fine examples of latest applications of this theory, am a good many of the papers in M. E. Soule, editor, 1986. Conservation Biology: Science of Scarcity and Diversity, Smarter Associates, Sunderland, Mass. 38 O. Fraenzle, 1979, The Water Balance of the Tropical Rain Forest of Amazonia and the Effects of Human Impact, Applied Science and Development 13:88-117; H. Lettau, K. Lettau and L.C.B. Molion, 1979, Amazonia's Hydrologic Cycle and the Role of Atmospheric Recycling in Assessing Deforestation Effects, Monthly Weather Review 107: 227-238; and E. Salati and P.B. Vose, 1984, Amazon Basin: A System in Equilibrium, Science 225: 129-138. 39 B. Bolin, et al., 1986, The Greenhouse Effect: Climatic Change and Ecosystems, Wiley, New York; U.S. Department of Energy, 1985, State of the Art Reports on Carbon Dioxide, four books, Carbon Dioxide Research Division, Department of Energy, Washington D.C. 40 M.E. Soule, 1986, see footnote 37 above; M.E. Soule and B.A. Wilcox, editors, 1980, Conservation Biology, Sinauer Associates, Sunderland, Mass. See also J.A. McNeely and K.R. Miller, editors, 1984, National Parks, Conservation and Development: The Role of Protected Areas in Sustaining Society, Smithsonian Institution Press, Washington D.C. 41 R.L. Peters and J.D.S. Darling, 1984, The Greenhouse Effect and Nature Reserves, BioScience 35: 707-717, 42 N. Myers, 1983, A Wealth of Wild Species, Westview Press, Boulder, Colorado; and M.L. Oldfield, 1984, The Value of Conserving Generic Resources, National Parks Service, U.S. Department of the Interior, Washington D.C. 43 N. Myers, 1983, A Priority-Ranking Strategy for Threatened Species? The Environmentalist 3: 97-120. 44 U.S. Department of Agriculture, 1982, Introduction, Classification, Maintenance, Evaluation, and Documentation of Plant Germplasm, Agricultural Research Service, U . S. Department of Agriculture, Washington D.C. 45 H.H. Iltis, J.F. Doebley, R.M. Guzman and B. Pazy, 1979, Zea diploperennis (Gramineae), a New Teosinte from Mexico, Science 203: 186-188. 46 L.R. Nault and W.R. Findley, 1981, Primitive Relative Offers New Traits for Corn Improvement, Ohio Report 66(6): 90-92. 47 A.C. Fisher, 1982, Economic Analysis and the Extinction of Species, Department of Energy and Resources, University of California, Berkeley, Calif 48 N.R. Farnsworth and D.D. Soejarto, 1985, Potential Consequence of Plant Extinction in the United States on the Current and Future Availability of Prescription Drugs, Economic Botany 39: 231-240. 49 N. Myers, 1983, see footnote 42 above. 50 J.A. Duke, 1980, Neotropical Anticancer Plants, Economic Botany Laboratory, Agricultural Research Service, Beltsville, Maryland. See also M. Suffness and G.A. Cordell, 1985, Antitumor Alkaloids, in The Alkaloids 25: 1-355, Academic Press, New York. 51 M.L. Oldfield, 1984, see footnote 42 above; B.C. Palsson and three others, 1981, Biomass as a Source of Chemical Feedstocks: An Economic Evaluation, Science 213: 513-517; and L.H. Princen, 1979, New Crop Development for Industrial Oils, Journal of the American Oil Cbemists' Society 56(9): 845-848. 52 H.M. Benedict, et al., 1979, A Review of Current Research on Hydrocarbon Production by Plants, Solar Energy Research Institute, Golden, Colorado; M. Calvin, 1980, Hydrocarbons from Plants; Analytical Methods and Observations, Naturwissenschaften 67: 525-533; C.W. Hinman, A. Cooke and R.I. Smith, 1985, Five Potential New Crops for Arid Lands, Environmental Conservation 12: 309-315; and Sonalysts, Inc., 1981, Assessment of Plant Derived Hydrocarbons, Report for Department of Energy, Washington D.C., Sonalysts, Inc., Waterford, Conn. 53 T. Eisner, 1983, Chemicals, Genes, and the Loss of Species, Nature Conservancy News 33(6): 23-24. 54 For some leading literature of recent vintage on evolution, see N. Eldredge, 1986, Time Frames, Simon and Schuster, New York; D. Jablonski and D. Raup, editors, 1986, Patterns and Processes in the History of Life, Springer Verlag, New York; E. Mayr, 1982, see footnote 11 above; R. Milkman, editor 1982, Perspectives on Evolution, Sinauer Associates, Sunderland, Mass.; J.W. Pollard, editor, 1985, Evolutionary Theory, Wiley, New York; and S.M. Stanley, 198 1, The New Evolutionary Timetable, Basic Books Inc., New York. 55 M.E. Soule and B.A. Wilcox, 1980, see footnote 40 above. 56 P.J. Darlington, 1957, Zoogeography: The Geographical Distribution of Animals, Wiley, New York; and E. Mayr, 1976, Evolution and the Diversity of Life, Harvard University Press, Cambridge, Mass. 57 N.C. Stenseth, 1984, The Tropics: Cradle or Museum? Oikos 43: 417-420. 58 D. Jablonski, 1986, Background and Mass Extinctions: The Alternation of Macroevolutionary Regimes, Science 231: 129-133; see also D. Jablonski and D.M. Raup, 1986, see footnote 54 above. For a further first-rate paper on past extinctions, see D.M. Raup, 1986, Biological Extinction in Earth History, Science 231: 1528-1533. 59 G.T. Prance, editor, 1982, Biological Diversification in the Tropics, Columbia University Press, New York. 60 A.H. Knoll, 1984, Patterns of Extinction in the Fossil Record of Vascular Plants, in M.H. Nitecki, editor, Extinctions; 21-68, University of Chicago Press, Chicago, Illinois. 61 On the ethical dimensions of species preservation, see B. DeVall and G. Sessions, 1985, Deep Ecology: Living as if Nature Mattered, Peregrine Smith Books, Layton, Utah; T. Regain, 1983, The Case for Animal Rights, University of California Press, Berkeley, Calif.; H. Rolston, 1985, Duties to Endangered Species, BioScience 35: 718-726; and M. Tobias, 1985, Deep Ecology, Avant Books, San Diego, Calif. 62 For further clarification, see N. Myers, 1983, footnote 43 above. 63 EA. Pitelka, 1981, The Condor Case, An Uphill Struggle in a Downhill Crush, Auk 98: 634-635 64 R.E. McCabe, 1986, personal communication, letter of February 5th, 1986, Director of Publications, Wildlife Management Institute, Washington D.C. 65 L.E. Gilbert, 1980, Food Web Organization and Conservation of Neotropical Diversity, in M.E. Soule and B.A. Wilcox, editors, Conservation Biology: 11-33, Sinauer Associates, Sunderland, Mass.; and J. Terborgh, 1986, Keystone Plant Resources in the Tropical Forest, in M.E. Soule, editor, Conservation Biology: Science of Scarcity and Diversity: 330-344, Sinauer Associates, Sunderland, Mass. 66 D. Western, 1987, "Conservation 2 100, " Proceedings of Conference on Wildlife in the Future, organized by Wildlife Conservation International, New York Zoological Society, New York (in press). 67 D. Jablonski, 1986, see footnote 58 above. 68 For instance, we can calculate - albeit in rough and ready terms, and for ilImitative purposes only - the commercial cost in the medicinal field of allowing a species to become extinct. (Let us bear in mind, as demonstrated by the case of the Madagascar periwinkle, that the economic cost is likely to be much greater.) Scientists have so far conducted detailed examination of only about 5,000 of the 250,000 species (minimum number) of higher plants. Of these 5,000 analyzed, 41 have produced materials that serve our health needs in one way or another (N.R. Farnsworth and D.D. Soejarto, 1985, footnote 48 above; see also P.P. Principe, 1985, The Value of Biological Diversity Among Medicinal Plants, Environment Directorate, Organization for Economic Cooperation and Development, Paris, France). These 41 species now generate commercial sales worldwide each year worth about $40 billion, or an average of almost $1 billion each. (Of course the genetic materials contribute only a limited part of the eventual commercial value, which also reflects the costs of collecting wild-plant tissue, analysis and research, production and marketing, etc. But the pharmacologist is no better than the raw materials he has to work with, so even if the genetic contribution represents a small part of the end-product, it is an essential part.) Let us suppose the 245,000 species still to be subjected to systematic analysis were to come up with "winners" at a rate of one for every 122. Let us also accept that at least one plant species in ten is now threatened, and could well be eliminated by the year 2000 (one plant species in four could disappear in tropical forests alone by the year 2050, according to P.H. Raven, 1985, see ref. 31 above). If these 25,000 threatened species were to offer medicinal potential at a rate of one in every 122 species, then we should lose 205 species with materials for drugs. Of course some of the drugs may serve the same purpose, so there could be some overlap between the benefits supplied by the species in question; and some of the drugs could prove to be amenable to synthesis in the laboratory. But in terms of the "back of an envelope" calculations presented here, this spasm of plant extinctions could cost us $205 billion each year in medicinal terms alone. This figure is to be compared with a crude-estimate cost of expanding our present network of protected areas until it caters to the needs of the majority (though not the totality) of all species on Earth, both plants and animals, viz. some $2 billion a year for ten years. 69 For some notable exceptions to the lack of attention on the part of social scientists see R.C. Bishop, 1978, Endangered Species and Uncertainty: Economics of a Safe Minimum Standard, American Journal of Agricultural Economics 61: 10-18; A.C. Fisher, 1982, see footnote 47 above; and D.W. Pearce, 1983, The Economic Value of Genetic Materials: Methodology and Case Illustration, Discussion paper prepared for the Environment Directorate of the Organization for Economic Cooperation and Development, University of Aberdeen, Scotland, U.K. 70 M.E. Soule, 1985, What is Conservation Biology? BioScience 35(11): 727-734. See also M.E. Soule, editor, 1986, footnote 37 above. 71 E.S. Muskie, speech while Secretary of State, June 5th (Environment Day) 1980, Department of State, Washington D.C.
I thank Professor David Jablonski, University of Chicago, for his valuable comments on the evolution section of the text; and Steve Greenwood University of Oxford, for checking through the entire text and providing many helpful criticisms. Introducing: Norman Myers Dr. Myers was born in Whitewell, Yorkshire, England. He was a student at Oxford University, where he completed the M.A. degree in 1957 and received a Diploma in Overseas Administration in 1958. He completed the Ph.D. degree from the University of California at Berkeley in 1973. Following his university training, Dr. Myers worked on various consultancy assignments while writing a number of major books in the field of resource conservation. These include: The Sinking Ark (1979), which identified the international problem of species extinction; Conversion of Tropical moist Forests (1980), in which was developed the first worldwide data base on the conversion of tropical forests; A Wealth of Wild Species (1983), which covered the variety of wildlife found in tropical forests; The Primary Source: Tropical Forests and our Future (1984), which examined the significance of the loss of the tropical forest gene pool for future evolutionary development of plant and animal species; and An Atlas of Planet Management (1984), which covered our planet's resource crises and future prospects. Dr. Myers' expertise in the area of environment, ecology, and development
has won him both the Gold Medal and the Order of the Golden Ark,
presented by the World Wildlife Fund International. He has also
been honored as a Regents' Lecturer at the University of California
at Santa Barbara, as a Visiting Scholar at the Rockefeller Foundation,
and as a Visiting Fellow with the World Resources Institute, Washington,
D.C. He serves as a Senior Associate with the International Union
for Conservation of Nature and Natural Resources in Gland, Switzerland. |
Norman Myers, our 26th Albright Lecturer, is a consultant in environment
and development. Since 1970 he has worked on the general area of
environment and natural resources, with emphasis on species conservation,
gene resources, and tropical forests, He has conducted this consul
tancy work under the auspices of the Rockefeller Brothers Fund,
US National Academy of Sciences, UN agencies, the World Bank, the
Smithsonian Institution, and a number of conservation organizations.
His main professional interest lies with resource relationships
between the developed and the developing worlds.
