A Priority-Ranking Strategy for Threatened Sp ies ? NORMAN MYERS*
Upper Meadow, Old Road, Headington, Oxford 0)(3 9AP, U.K.
The rate o f extinction has accelerated to the point where we are probably losing one species per day right now, and we could well lose one million o f Earth's 5 - 1 0 million species by the year 2000, and a good many more within the early decades o f the next century. Plainly we cannot assist all species that face extinction within the foreseeable future. Conservationists have limited resources at their disposal, in the way o f finance, scientific skills, and the like. Even were these resources to be increased several times over, we could not hope to save more than a proportion o f all species that appear 'doomed to disappear': the processes o f habitat disruption are too strongly underway to be halted in short order. But when we allocate funds to safeguard one species, we automatically deny those funds to other species. Already we support only a small fraction o f all species under threat, and we may soon find ourselves in a situation where we can assist only a very marginal number o f species facing extinction. Thus a key question arises: how are we to allocate our scarce resources in the most efficient way to safeguard species? Indeed we may now have reached a stage where there is merit in determining which species are 'most deserving' o f a place on the planet. Agonizing as it will be to make choices along these lines, conservation strategy should be as systematically selective as possible. This means that we should design analytic methodologies to enable us to assign our conservation resources to achieve maximum return in terms o f numbers o f species protected. In essence, a 'triage' strategy. A n expanded approach along these lines postulates a quantum advance in our planning o f responses to the growing threatened-species problem: while the techniques o f the past have certainly helped the situation, we cannot confront the much greater challenges o f the future with an attitude o f 'the same as before, only more s o ' ~ t h e future will not be a simple extrapolation o f the past, but will represent a qualitatively larger set o f problems, which require an appropriately scaled-up response in our save-species campaigns. *Dr Norman Myers is an expert in the study of endangered species and ecosystems. He is an international consultant in Environment and Development. This paper is based in part on findings of a project that he conducted for the World Wildlife F u n d - - U S , to which grateful acknowledgment is made. The responsibility for all conclusions and recommendations remains, of course, with the author. 0251-1088/83/$3.00
Conservation of species--discussion on the necessity of making choices among threatened species
INTRODUCTION The problem of disappearing species is becoming increasingly acute. Of earth's 5 - 1 0 million species, only 1.6 million have been identified by science, and a far smaller number has been assessed for their survival prospects. Of species recognized b y science to be threatened, it is generally believed that at least two or three vertebrates and two or three plants (possibly more) are becoming extinct each year. But if we consider all species on Earth, and the rate at which natural environments are being disrupted if not destroyed, it is not unrealistic to suppose that we are losing at least one species per day. By the end of the 1980s, we could be losing one species per hour. It is entirely possible that by the end of the century, we could well lose as many as one million species, and a good many more within the following few decades (Council on Environmental Quality, 1980; Ehrlich and Ehrlich, 1981;Myers, 1979, 1980 and 1982). At the same time, it is becoming plain that we cannot assist all species that face extinction within the foreseeable future. Conservationists have limited resources at their disposal--finance, scientific backup, etc. Even were these resources to be increased several times over, we could not hope to save more than a small proportion o f all species that appear d o o m e d to disappear: the processes o f habitat disruption are too strongly underway to be halted in short order. When we allocate funds to safeguard one species, we automatically deny those funds to other species. This means that we perforce allocate our conservation r e s o u r c e s - - a n d thereby assign p r i o r i t y - - t o certain species in preference to others. In short, we choose in favour of some
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species and against other species. We may choose unwittingly rather than deliberately; but we choose. Hitherto conservationists have tended to support those species that receive most attention. As a result, they focus on species that are known to science, are known to be threatened, and generally offer some measure o f public appeal. By contrast, species with a less 'glamorous' image receive far less attention; and species that have not yet been recognized by science and hence remain uncategorised as regards their survival prospects, receive virtually no attention. Included in these latter categories are practically all invertebrates, which constitute some 80 percent o f all species. Thus present conservation programmes i m p l y - - w i t h o u t conscious intent,
for sure, b u t effectively n o n e t h e l e s s - - t h a t the great majority of earth's species are deemed 'insufficiently worthy' o f preservation efforts. Yet it is among the 'unconsidered 80 percent' that the great bulk o f extinctions are now occurring, as a consequence of, for example, broadscale habitat disruption in tropical rainforests with their exceptional concentrations o f species. Already we support only a small fraction of all species under threat. Before long we may find that we can assist a still smaller proportion of all species facing extinction. Thus a key challenge for conservationists lies in the most efficient way to allocate funds and related resources (e.g., scientific expertise) for their savespecies programmes. We may now have reached a stage where there is merit in determining which species are 'most deserving' o f a place on the planet in the future. Agonising as it will be to make choices along these lines, conservation strategy needs to be made as systematically selective as possible. In other words, the erstwhile limited approach needs to be complemented by a broader, more methodical approach, that seeks to determine, for example, which groups of species are unusually vulnerable to summary extinction, which groups make outstanding contributions to ecosystem stability, which groups are of significant economic value to humankind, and so f o r t h - and which groups are, willy-nilly, less 'worthy' and less likely to qualify for our limited conservation measures. In short, we need to devise an analytic methodology that supplies us with an evaluatory ranking o f priority among species.
HOW TO DETERMINE PRIORITIES?
(b) Fig. l ( a ) and (b). Tiger (Panthera tigris). Although the tiger absorbs many millions of dollars in safeguard efforts, it is plainly worth the outlay, on grounds of its public appeal, its ecological role as a top predator, and, perhaps most important of all, because of the fact that when we protect the tiger's ecosystem, we protect the habitats of many other species. (Photo Credits: Arjan Singh/ WWF and Peter Jackson/WWF.)
This is not to gainsay the 'ethical rationale' in support o f species preservation. Many conservationists legitimately point out that all species may be deemed to possess an equal right to exist in principle, and they should be enabled to enjoy that right in practice. To put it another way, all species, as manifestations of life's diversity that emerged before man achieved dominance over earth's ecosystems, should be accorded equal right to be safeguarded against 'unnatural' extinction at the hands of man. The intrinsic merit o f this argument is not in question here. But in the world of everyday a f f a i r s - - a world that does not always recognize ethical d i c t a t e s - conservationists increasingly find themselves obliged to qualify their absolutist stance on behalf o f species' 'right to live'. But how are choices to be made? How shall The Environmentalist
we decide between the Bengal tiger (Fig. l(a) and (b)) and a crab in the Caribbean? When we come to ecosystems with their entire communities o f species, and we try to apply our priorityranking analysis to these larger entities, shall we focus, with respect to tropical rainforests for example, on remnant patches of forest in countries that have experienced decades of destruction, or shall we try to 'lock away' vast tracts of forests in regions that have been little touched? A host o f similarly crucial questions will arise, and they will all demand difficult decisions. We could make a start through systematic analysis o f bio-ecological 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 economic, political, legal and sociocultural aspects of the situation: the Bengal tiger requires large amounts of living space in a part of the world that is crowded with human beings, b u t it could stimulate more public support for conservation o f its ecosystem (and thereby help save many other species) than could a less-than-charismatic creature such as a crab. When we integrate all the various factors that tell for and against a species, we shall have a clearer idea o f where best we can apply our conservation muscle. Many tough decisions will have to be made. N o b o d y will like the prospect of deliberately consigning certain species to oblivion. But insofar as man is certainly consigning huge numbers to oblivion, he might as well do it with as much selective discretion as he can muster. In other words, conservationists should make their choices among species explicitly rather than implicitly: they should determine the future of species by design rather than by default. True, there are major risks entailed in an approach of this sort. The strategy may be poorly understood by certain sectors o f the public. As a consequence, it may be mis-used, even abused. Some observers, failing to recognise the premises underlying the approach, may assert that it proposes that some species are simply not worth saving. But this would represent a basic misinterpretation of the strategy: in principle, all species are worth saving, yet in practice we cannot possibly succeed in saving them all. In view of these objections, the new strategy will have to be scrupulously careful, b o t h in spirit and in practice, to avoid any possible misunderstandings. From start to finish, its aims and procedures must be clearly spelled out. As long as this critical constraint is recognized, it need present no massive obstacle. Vol. 3, No. 2 (1983)
POTENTIAL AREAS OF RESEARCH In order to come to grips with the challenge, we shall need to assess several potential areas of research, to see how much light they can shed on a perplexing problem. A number of such research areas are considered below, and, since they are reviewed in some detail, they make up the bulk of this paper. This is not to overlook, o f course, at least two previous attempts to achieve a systematized ranking o f threatened-species priorities. These two formulations have been presented by the Species Survival Commission o f the International Union for Conservation of Nature and Natural Resources, and b y the Endangered Species Office o f the US Department of the Interior. Both these priority-ranking strategies look at a series of key factors, such as degree of threat, bio-ecological (and occasionally economic) values associated with species, and prospect of success if a safeguard effort is launched. In these respects, the two initiatives represent a laudable attempt to introduce some order and method into our response to the threatened-species problem; and they are particularly commendable in that they seek after quantification of criteria in question. The present paper attempts to build out from these early initiatives, and take account of some broader perspectives. For example, under the heading of Biological Attributes (see below), the paper offers some thoughts on the controversial issue of whether island species do not receive undue attention from conservationists, and it asks whether certain taxa do not deserve special attention by virtue of their utilitarian benefits (e.g. their potential for anti-cancer materials). In other words, the two earlier analyses have assumed that any species declared to be threatened is automatically reckoned to deserve assistance of some form. By contrast, the present approach accepts that the number of species under threat is far too great for us to help them all, hence we must invoke more comprehensive criteria if we are to come to grips with the overall problem o f species disappearing in their many t h o u s a n d s - - a n altogether different category of problem from the earlier problem. Within this larger context, the present writer raises more questions than he answers. Indeed this paper, far from presenting any solutions or set of solutions, is more speculative and exploratory in scope and intention. Far from establishing quantification o f critical parameters, it rather seeks to touch base with all parameters at issue, thus with emphasis on qualitative analysis. The ultimate aim of the paper is to assess the 99
dimensions of the threatened-species problem as it lies ahead of us (by contrast with the way it has been handled in the past), and to suggest some directions for urgent research if we are to confront the problem in its proper scope and scale.
Biological A ttribu tes
Let us start the categorization of purported values represented b y species, by looking at some biological attributes. This is an obvious point o f departure, even though, in biological terms, the main thing that we know about the planetary spectrum o f species is that we know all too little about a few species, next to nothing about many species, and absolutely nothing about most species. We do not even know how many species exist on Earth b e y o n d an estimate o f somewhere between three and ten million. Only about 1.6 million have been identified by science, and most o f these have been documented only in terms of their taxonomic definition, place o f occurrence, and one or two morphological features. So any generalizations about biological values must be general to a degree. Certain species appear, by virtue of their biological attributes, to be predisposed to problems o f survival--and hence these species deserve special attention from conservationists. An obvious case in point is those species that are rare. An example lies with island species. Two key traits of many threatened species, viz. localized distribution and specialized lifestyles, often characterize island s p e c i e s - - a combination o f circumstances that makes island species extremely vulnerable to extinction (Carlquist, 1974; Diamond, 1975; Lack, 1976; MacArthur and Wilson, 1967; Terborgh, 1974). Only around 20 percent o f all bird species are island dwellers, yet around 90 percent of birds driven extinct in historic times have been island species. Their extreme vulnerability seems due to their tendency to evolve with specializations that suit them for survival in confined localities, with few competitors and next to no predators. This evolutionary equipment leaves them grossly unable to cope with disruptive competition on the part o f creatures brought in from outside b y man, notably goats, pigs, rats, dogs and cats. What were formerly enclaves o f security turn into 'killing grounds' from which there is no escape. In addition, island species are ill-adapted to forest felling, grass burning and other incursions on the part o f modern man. Because o f their vulnerability, island species tend to receive special attention from conserva1O0
tionists. Clearly there is much to justify this reaction. At the same time the situation is not such a straightforward 'must' for conservationists as it might appear. One may speculate whether many island species are not 'evolutionary aberrants', with little to contribute to biosphere processes and to evolution. Conversely, one can speculate whether the extreme specializations o f island species may not throw light on mechanisms of evolutionary adaptation. (For example: certain species on a few small islands appear to have emerged through processes o f speciation that are not found elsewhere, insofar as small or sedentary organisms seem to need less space to produce two or more contemporaneous species than do largerbodied or vagile organisms.) So: with regard to both these categories of 'curiosity value' associated with island species, can we somehow assess the priority-action merits o f these threatened taxa in comparison with continental species? Furthermore we must bear in mind that, whatever the situation in the past, most animal species now designated as threatened are continental species. Indeed twice as many continental forms as island forms are now considered threatened. We may infer, with Frankel and Soule (1981) and Soule and Wilcox (1980), that island forms are simply less tolerant of man's incursions than are continental s p e c i e s - - a n d the tidal wave of extinctions that has inundated island species is now beginning to flood across continental biotas. Moving on from island species, can we pinpoint any categories of species, e.g. genera or families, that feature unusually sound or unusually poor 'survivorship' capacities? Clearly this consideration holds many implications for conservation planning. Much o f our evidence derives from land-bridge islands. Limited as these geographical localities are, the findings probably hold good as well for many 'ecological islands' located in the middle of continents. Man is now reducing wilderness territories to relict fragments, which means that species' habitats across even the largest land masses are becoming effective islands. According to extensive analysis o f Terborgh and Winter (1980), it seems that several families of birds often demonstrate unusual capacity for survival. These include pigeons, cuckoos, swifts, kingfishers, thrushes and sylviid warblers. Of these taxa, all are decisively better than average, though the first three are well ahead of the last three. The first five families comprise bird species that are strong flyers, and are disproportionately represented in the faunas o f oceanic islands. The Environmentalist
Several other families appear to be unduly vulnerable to extinction. These are falcons, pheasants, woodpeckers, babblers, tinamous, gunas, horndoves, and toucans. Of these, the first four families appear (on the basis of limited evidence from land-bridge islands--this point is stressed) to be far worse off than the last four. Moreover, the last four families all comprise large-bodied forest frugivores. Frugivores, in common with nectarivores, may feature apparently acceptable population sizes and densities, then suddenly become locally extinct. Their sudden demise is presumably due to their tendency to subsist off food stocks than can disappear completely in the wake of drought or frost. It is this phenomenon that may explain why many tropical hummingbird species are known, even in normal years, to vary drastically in abundance (Feinsinger, 1976). Among the categories of species that reveal poor 'survivorship' qualities in face of man's incursions into their life-support systems, are a good number of species that are known to biologists as 'K-selected' species. These unfor-
tunates include the whales, the rhinos (Fig. 2), several large birds such as seven out of fifteen crane species (Fig. 3) and many other creatures that seem pre-disposed to survival problems. K-selected species make unusually efficient use of particular environments (Miller and Botkin, 1974). Being adapted to an apparently stable situation, they direct less energy to producing many offspring, and more to caring for their young. In addition, they live for a long time, with lengthy gaps between generations. In other words, they balance off a high rate of increase (and thus an ability to exploit transient circumstances) against a low rate of increase, a correspondingly low rate of mortality, and a tendency to maintain stable numbers. All this means that they are closely adjusted to the long-term capacity of the habitats to support them. A sound strategy for predictable environments, this becomes a high-risk strategy for a man-disturbed world. If, through whatever cause, a K-selected species loses a large proportion of its numbers, it may prove critically unable to build up its stocks
Fig. 2. Black Rhinoceros. Like the other four species of rhinoceros, the Black Rhinoceros o f Africa is in poor straits. Yet its n u m b e r s were apparently dwindling before m o d e r n m a n arrived on the scene. So is the species suffering from 'geneological senility', and hence should be allowed to fade slowly from the Earth? A key q u e s t i o n - - b u t one that we are n o t permitting to be answered, since we are speedily elbowing it o f f the Earth. (Photo Credit: N o r m a n Myers.)
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Fig. 3. Whooping Crane (Grus Americana). The Whooping Crane has absorbed several million dollars since the 1960s. But this investment has enabled the species to increase its n u m b e r s from a few dozen to well over 100, and it can now be considered as 'safe'. (Photo Credit: WWF-UK.)
again, no matter what protection measures are provided. Thus special steps need to be taken to safeguard K-selected species while their numbers are still well above what would be acceptable levels in other species. A notable example of a K-selected species is the California condor. The bird does not breed until at least six years of age, it generally does not nest every year, and it lays only one egg. By contrast, the quail (an r-selected s p e c i e s - - s e e below) often nests during its second year, and lays 15 or more eggs per clutch. Thus a pair of condors must take ten or fifteen years to replace themselves with two offspring, whereas the quail achieves as much in its first year o f breeding. Many carnivores tend to be K-selected species. This applies especially to the larger predators, well-known examples of which are the cheetah, the African hunting dog, the mountain lion, the timber wolf, the polar bear and the tiger. Furthermore, carnivores occupy an ecological position toward the end of food chains, which makes them unduly vulnerable to disruption in their ecosystems. The term 'K-selected' can refer not only to individual species and to small groups of species. It can refer to entire communities o f species, e.g. the swarms of cichlid fishes in lakes o f eastern 102
Africa (Lowe-McConnell, 1975). In these 'ecological islands', there are extraordinary numbers of endemic species. Lake Malawi, possessing almost 400 species o f fish, or far more than any other lake in the world, supports over 200 cichlid species, all but four of them being endemic. Lake Tanganyika features 134 endemic s p e c i e s - and, although only 320 km away from Lake Malawi, it does not have a single cichlid in common with Lake Malawi. Obviously these fish swarms deserve priority attention from conservationists: they could prove even more important for the study o f evolution than the fauna o f the Galapagos Islands. Interpreting the term 'community' in a very broad sense, we can consider that tropical-forest birds are, generally speaking, K-selected species (Cody and Diamond, 1975; Lovejoy, 1974). They tend to have low reproduction rates, laying two to three eggs at a time, instead of the four to six o f temperate-forest birds. Because of more intensive predation in tropical forests, their ratio of young fledged to eggs laid is low compared with temperate-forest birds. Having evolved within relatively stable environments, they are unusually sensitive to disturbance of any kind. Taken altogether, these factors mean that tropical-forest birds are slow to recover from perturbation in their life-support systems, b y contrast with temperate-forest birds whose numbers 'bounce back' from population crashes within a few seasons. Partly because they are adapted to the darkness of their environments, many tropical-forest birds cannot tolerate bright areas. They even avoid forest streams and game trails, while small manmade intrusions such as park roads can represent insurmountable barriers. This means that tropicalforest birds are little inclined to disperse away from man-disruptive activities in their habitats. By contrast, two out o f three forest bird species in eastern North America are partially or wholly migratory, which makes them well adapted for dispersal. In addition, having lived in a primary forest environment for millions o f years, tropicalforest birds have had no need to cope with secondary growth such as springs up when primary forest is cleared, whereas temperateforest birds mostly find secondary vegetation acceptable. These various attributes make tropical-forest birds exceptionally sensitive to disturbance. Of more than 400 bird species and sub-species listed as threatened in the Red Data Books, roughly three-quarters occur in tropical forests. As large tracts of tropical forests become degraded or are eliminated, the fallout o f bird The Environmentalist
species is likely to be high. By contrast, temperate-forest birds are better able to live with man's activities: during the period when the forests of the eastern United States were severely reduced, only two bird species at most disappeared. Many o f these comments apply similarly to other tropical-forest communities, notably those with the most abundant and diverse arrays o f species, viz. the arthropods, mainly insects. A great majority of them can be characterized as K-selected species. By contrast with K-selected species, r-selected species demonstrate an entirely different set o f characteristics. They are usually short-lived creatures, with brief gaps between generations, and with high rates o f increase. These traits enable them to disperse quickly into new environments, and to make excellent use of 'boom seasons'. Because of their opportunistic attributes and their built-in capacity to expand their numbers rapidly, they are successful in a mandisrupted world, to the extent that they often become pests. Examples include rats, rabbits, sparrows,~ starlings, and plants that become 'weeds'. Attention is drawn here to r-selected species solely on the grounds that they may well come to predominate in the depleted spectrum of species of the f u t u r e - - w h i c h implies that conservatibnists should accord particular attention to t~ose predatory and parasitic species, often K-selected species, that can keep r-selected species in control. Indeed the reduced array of species that survives into the foreseeable future will probably contain a disproportionate number of opportunistic or 'clever' species. A spasm of extinctions, such as appears to be the prospect ahead o f us, could be accompanied by an outburst of speciation. Of course, a new species emerges only slowly as compared with man-caused extinction; but the next few decades might witness a speeding-up of certain aspects of evolution. As large sectors: of the species spectrum disappear, numerous niches will be opened up for newlyemerging species to occupy. It is possible that the first 'waves' of new species will tend to be characterized by pioneering species of opportunistic type, i.e. r-selected species. Because of their capacity to proliferate, and to thrive in successional environments, these species seem able to 'learn' how to get along with man. True, there is no great harm in a trend that favours opportunistic species, insofar as they are slow to settle into specialized lifestyles and contain much potential for evolutionary a d a p t a t i o n - - a n d to this extent, the genetic variability o f an opportu•
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nistic species can be considered to be greater than that o f a more 'developed' species. At the same time, we shall probably find that we shall need to help the likely 'losers', in order to restore some kind of balance between these two basically different categories o f species• These are questions that need to be investigated urgently, and that have hardly been looked at. About all that can usefully be said here is that opportunistic species tend to become pests. It is entirely possible that man, through unconsidered intervention in evolution's course, is triggering processes that will eventually lead to a disproportionate number of 'plague species'• True, this derogatory designation now applies to far less than five percent o f all species, even in the most problematic category such as insects• But the eventual prospect, i.e. of many more pest species, will be all the more difficult to handle if meantime we have eliminated undue numbers o f species that, as predators and parasites, could keep opportunistic species in check. Predators and parasites, often with specialized lifestyles, tend to be K-selected species, i.e. unduly prone to extinction• If selective patterns o f extinction were to result in a disproportionate total of clever species surviving, this could mean that the relative number of harmful species could eventually expand beyond the capacity o f natural enemies to control them. So much for K-selected and r-selected species. Let us now look at an entirely different class of biological attributes, viz. taxonomic uniqueness. When a species is a sole extant representative of a taxonomic grouping such as a genus or a family, there is a prime facie case that it deserves a ranking above another species that shares a genus with perhaps ten other species. Thus preference should be accorded to monotypic groups, such as solenodons (Fig. 4), aardvarks, hoatzins, the ayeaye and the tuatara (Fig. 5) (Lovejoy, 1979)• How to assess the amount of priority that a taxonomically unique species should receive? Clearly, if the hoatzin is still fairly numerous in the wild, it should receive less priority consideration than the tuatara. But how to categorize the 'value' that should be placed, for instance, on the po'o-uli (a bird recently discovered on Hawaii, and assigned to a new genus) in comparison to, or in 'conservation competition' with, the solenodon? How far should conservationists accord preferential treatment to, say, the coelocanth? Similar questions apply to groups that are less monotypic but tend to suffer group-wide threat. Examples include the tapirs, pangolins and rhinoceroses, and, to less extent, the equids and marsupials. 103
Fig. 4. Solenodon (Solenodon paradoxus). Still surviving, though only just, on the islands of Haiti and Cuba, the rabbit-sized Solenodon is a very primitive and remote relative of the modern shrew. Because o f its taxonomic curiosity, the Solenodon surely deserves our best efforts on its behalf. (Photo Credit: V. H. S. Burroughs/
Fig. 5. Tuatara (Sphenodon punctatus). The strange TLiatara o f New Zealand is the last survivor of an ancient order of reptiles, and the only living animal that perpetuates, with virtually no change, the basic anatomical features of reptiles dating back well over 200 million years ago. As a 'living fossil', then, the Tuatara enjoys exceptional scientific interest, and thus merits exceptional conservation efforts. (Photo Credit: W. Stangenberg/WWF.)
Obviously a systematic ordering of priorities for these taxa is urgently required. To date, however, taxonomists, systematists and other scientists, together with conservationists, have directed next to no attention to this front-rank question. The issue calls for immediate investigation. 104
Finally, let us consider certain categories o f species that can assist us with our understanding of one o f Earth's most important life processes, that of evolution. Curiously enough, our analysis reveals that some 'unlikely' taxa feature exceptional evolutionary phenomena that illuminate our understanding of neo-Darwinian t h e o r y - - n o t a b l y a few obscure molluscs and earthworms. In similar style, we can note that certain groups o f species demonstrate crucial mechanisms in keeping the process of evolution underway, notably the mechanism of adaptive radiation; and this means that there is not nearly so much point in saveguarding a single species of Hawaiian h o n e y c r e e p e r ' o r Darwin's finch, as in safeguarding the entire group in question (Lovejoy, 1979). We should also direct attention to those taxa in which evolutionary rates apparently operate unusually fast. These tend to be taxa with rapid turnover rates, and/or characterized by many scattered sub-populations. Both these traits are preeminently exhibited by insects. It is because of these traits that the 'evolutionary clock' ticks faster for insects, as for many other small organisms. This tendency is clearly demonstrated by disease and pest systems, where significant evolutionary changes can take place in just a few decades, even in a year or two. Indeed there is a case for saying that, if we wish to look out for those species that can best maintain the processes o f evolution, we should accord some degree of priority to taxa with greatest potential for evolutionary advance, notably the insects and other arthropods. Many insect species can produce dozens of generations within a single season, throwing o f f progeny totalling 10 million billion billion (24 noughts). During this process there is massive opportunity for the forces of natural selection to pick out 'fitter' variations. Although we do not generally know how long it takes for one species o f animal to throw o f f another or several species, the time-scale for insects could be confined to a matter of dozens o f years, by contrast with thousands for large mammals such as whales. It is considerations such as these that explain why there are certainly 100 and perhaps 1000 times as many insect as vertebrate species. Furthermore, this all means that insects, with their quick-response adaptability, are, compared with most species, better suited to survive the environmental upheavals o f man's activities during the foreseeable future. It is worthwhile here to relate this factor, viz. evolutionary potential as manifested through rapid turnover rates, to a related factor o f genetic The Environmentalist
diversity (see below). From a genetic standpoint, a single pair o f mating organisms are capable of massive scope for variation. This is due to two factors. First, the process of forming sperm cells and egg cells causes much shuffling of chromosomes, or groups of genes. This shuffling can produce an almost unlimited number of genetically distinct cells. When the two kinds o f cells come together to form a new organism, the number o f genetic possibilities soars. In principle, two parents could produce trillions upon trillions o f genetically distinct individuals, a total that would be written as 5 followed by 47 zeros. A discrete population could lead to genetic variation that would be represented as 101°°° (1 followed by 1000 zeros), a figure to be contrasted with astronomers' estimates for atoms in the entire universe, 10 s°. Theoretical as may be these speculations, there could come a time when conservationists will need to give them due attention while devising optimal strategies for selecting those threatened species that are most capable o f maintaining the future course of evolution.
Ecological Attributes Species are necessary components of healthy ecosystems, just as healthy ecosystems underpin the planet's capacity to support life o f all kinds, including human life. Fundamental questions to be asked are: which species contribute more than others? Are certain species essential to the survival o f their ecosystems, and can some species be considered superfluous to the vigorous workings of their ecosystems? While the disappearance o f a species must constitute an impoverishment for its ecosystem, the loss can range from 'regrettable but marginal' to 'critical if not worse': how far does our ecological understanding now enable us to establish a gradient o f 'loss significance' through comparative evaluation of species' contributions to their ecosystems? These questions o f ecological attributes can be broached through the concept o f energy f l o w - insofar as energy flow serves as a measure of a species' relative importance (Ehrlich and Ehrlich, 1981; Odum, 1969; and, for some dissident views, Elton, 1973). If all bird species in a temperate-zone ecosystem amount to, say, 0.5 percent o f animal biomass, and their contribution to energy flow can be measured only at several places to the right of the decimal point, h o w is their role in the ecosystem's healthy functioning to be evaluated in comparison with that o f arthropod species that amount to, say, 10 percent of the biomass, thereby contributing an even larger proportion of energy flow? Similarly, do Vol. 3, No. 2 (1983)
some species contribute more than others b y virtue o f their numbers rather than their biomass? Or b y their status in their food pyramids? A related question concerns the theoretical relationship between biological diversity and ecological stability. It is sometimes proposed that the more numerous an ecosystem's species, the greater the ecosystem's stability. There is much evidence for an association between these two characteristics (Goodman, 1975; May, 1973; Usher and Williamson, 1974; Van Dobben and Lowe-McConnell, 1975). For one thing, more species can use the sun's energy more efficiently than can a few. For another thing, an ecosystem can probably withstand perturbations better if each species can depend on many rather than few food sources, and be regulated b y many rather than few p r e d a t o r s - - w h e r e u p o n the eggs-in-onebasket effect is reduced. Not that the idea is to be taken in the simple sense that variety is the essence of life. The relationship is far more complex. Diversity in this context refers to quality as well as quantity o f difference among species, while stability can refer to numbers and relative abundance of species, or to dominance b y a few species. So to assert that diversity equals stability is to overstate the case (May, 1973). A more concise way to express the situation might be to say that diversity and stability have had evolutionary relationships that run parallel without being causal. Alternatively, one can say that high environmental stability leads to higher community stability, which in turn permits, though is not determined by, high diversity o f species. An alternative way to broach this question is to look at the 'keystone' role played b y certain species in their ecosystems, notably tropical forest species (Gilbert, 1980; Gilbert and Raven, 1975; Janzen, 1975). Among the more important groups of species are bees, ants, bats, and hummingbird~ These species usually pollinate a number of obligate-outcrossing plants; or they may assist in dispersal o f seed. The ecological input of these categories of species can be best perceived within a context of food webs. A patch o f tropical forest features many parallel and host-restricted food webs. While similar in their trophic organization, these food webs differ from each other in their taxonomic makeup. Existing in many hundreds, in even a small patch o f tropical forest, each o f these sub-systems may depend upon just a few keystone species that serve as 'link organisms'. For a salient illustration o f this function, we can consider the orchid bees, or euglossine bees, o f Neotropical forests. Often enough, these 105
irridescent insects are intimately related to hundreds of plant species in a single locality. One species o f bee may feed from plant species in all strata and stages of the forest, linking them into a system of indirect mutualism. For example, females gather pollen from successional plants such as Solanum and Gassia, in some cases being the primary p o l l i n a t o r s - - a n d females may travel great distances in foraging, thereby being important to the reproduction of many low-density plants. Male euglossines serve a similar specialist function by pollinating epiphytic species such as Spatiphyllum and Anthurium. Certain euglossine species rely on early successional plants for larval resources; at the same time they are important, even necessary, pollinators o f plants restricted to later successional stages of the forest ecosystem (which means, in turn, that certain categories of species, e.g. canopy orchids and aroids, may depend, via indirect resource relationships, upon early successional patches of forest). So multifaceted are the interdependency functions that are facilitated by these bees, that proliferant arrays o f plants and animals may owe their origin, in part, to an abundance of euglossine stocks (Williams and Dressier, 1976). In turn, this means that euglossines could have played a major part in the emergence of many entire communities of tropical f o r e s t s - - w i t h all that implies for evolutionary patterns of the past, and evolutionary potential o f the future. In short, a sector of primary forest, with a variety o f successional taxa, can feature many 'specialization linkages' between host plants and pollinator insects. In the case o f euglossine bees, this depends, o f course, on the insects not having to fly too far to find their food supplies. Under man's impact, however, the forest tract may be reduced to fragments; or parts of it may be protected in the form of overly-small preserves, with isolated habitats. In these circumstances, several successional plant species may become locally extinct. In turn, the euglossines then find that they can no longer manage to commute an extended distance between their dispersed food s t o c k s - - w h e r e u p o n they fade from the scene. In turn again, the bees' demise leads to the decline of many further plant species. The process ends in a 'domino effect' series of extinctions at all strata, stages, trophic levels and community types o f the forest. Thus the crucial role of these 'mobile links', a term that refers not only to euglossine bees but to hummingbirds, bats and other pollinators, also seed dispersers. In the first instance, these mobile links may find sufficient support for themselves in just a few plant species--these 106
being plants that, by supplying food to extensive associations of mobile links, can be termed 'keystone mutualists' (Gilbert, 1980). If a single one o f these keystone mutualists becomes extinct, the loss to the ecosystem can eventually prove severe. The initial decline o f mobile links will precipitate, via breakdown in reproduction and dispersal mechanisms, multiple losses of interrelated plants. In turn again, as host communities become impoverished, there will be a steady disappearance of host-specialized insect species. The eventual upshot is a host of 'linked extinctions', through a ripple effect that spreads throughout the ecosystem (Futuyama, 1973). Notable among keystone species are 'top predators'. Top predators can regulate populations of their prey species (Eisenberg, 1980; Terborgh and Winter, 1980). So great can this regulatory function become, with its disproportionate repercussions for ecosystem stability, that the importance of top predators can hardly be over-emphasised. At the same time, top predators tend to be unduly prone to extinction, through over-hunting, poisoning programmes and other activities on the part of man. While we tend to think of top predators in the form o f the lion, leopard, jaguar, cougar and wolf, we should also consider other types, such as the large myrmecophages, e.g. the aardvark, giant anteater and giant armadillo. All of these can exert a stabilizing influence on their ecosystems. By way o f a somewhat esoteric illustration, the loss of a top predator in a rocky marine intertidal ecosystem can lead to drastic simplification o f the residual c o m m u n i t y (Paine, 1966). While exercising their key functions in ecosystems, top predators nonetheless exist at very low densities. They also tend to be large in body size, and to breed slowly. Even the largest preserves can feature only small breeding populations of top predators. Since this means a limited gene pool, the result can be a loss o f genetic variability, with subsequent decline in fecundity through inbreeding (see below). Finally, let us consider indicator species. Certain species assist us with baseline monitoring o f what is happening to natural environments. This serendipity value o f species, while often difficult to identify ahead of time, is becoming all the more important as we encounter growing need to monitor the health o f our environments. Thus the esoteric contribution of 'indicator species'. Regrettably, indicator species tend to be threatened species. A species in trouble often signals general ill health in an ecosystem that may thereby contain other threatened species. For example, the cheetah (Fig. 6), a highly specialized The Environmentalist
Fig. 6. Cheetah. The cheetah in Asia used to enjoy as wide a range as that of the cheetah in Africa. Now the cheetah in Asia has been all b u t eliminated, and the African variation is following a similar track. Yet the cheetah serves as a sensitive 'indicator species': when cheetah populations decline, we can suspect that their entire ecosystems are suffering problems. Moreover, because o f its physiological makeup, allowing the animal to sustain a high-speed chase for several h u n d r e d yards w i t h o u t immediately detrimental oxygen debt, the cheetah m a y offer clues to medical researchers who seek answers to h u m a n health problems such as heart disorders, respiratory troubles and circulatory problems. (Photo Credit: N o r m a n Myers/Fauna and Flora Preservation Society.)
predator, plays an important role in regulating savannah ecosystems. By virtue of its susceptibility to more threats than seem to afflict the lion, leopard, and other predators (threats such as changes in prey communities and vegetation patterns), the cheetah can give warning o f environmental stress when its numbers decline markedly (Myers, 1975). Similarly, we have to thank the peregrine falcon, the brown pelican and other birds of prey for drawing attention to DDT and other toxic pollutants that, when they reach excessive levels in the environment, prove poisonous to carnivores, including man. It is this role o f 'indicator species' that makes them especially useful to human society, in ways we do not anticipate until they flash a red light concerning new threats to our welfare. The most sensitive indicator species are often those at the end of food chains, i.e. those that concentrate contaminant materials in their tissues. At the same time, their position at the end of food chains usually means that they occur in small numbers as compared with, say, herbivores, which makes them more susceptible to extinction. Vol. 3, No. 2 (1983)
Genetic Attributes It is sometimes postulated that, by preserving species, we maintain the Earth's gene pool with all its manifold diversity (a line o f reasoning that is taken to underpin the activities of IUCN's Survival Service Commission). Constructive as this approach is, a number o f fundamental questions immediately arise. Do some species feature more genetic diversity than others? Are some species more capable than others o f fostering genetic diversity in the future, during the course of evolutionary processes? Hitherto, and to the extent that these questions have been addressed at all, we have had to supply answers in predominantly qualitative terms. In short, biologists have had to come up with 'best-experience judgements' in order to offer any answers. While far better than silence, these responses have not taken us very far down the road toward developIng conservation theory as a predictive discipline. Now, fortunately, we can call on some recent research to offer some quantitative, and hence more objective, answers. 107
To help us to assess genetic diversity, several analytic techniques have become available, notably electrophoresis, isoelectric focusing, chromosome banding and blood typing. Ostensibly the most helpful to date is electrophoresis. This technique examines blood and other body fluids, by separating variant protein molecules through their response to an electric current. Proteins vary in their composition, so they vary in their genetic control. Insofar as proteins are a direct expression of genes, the variation revealed in a sequence of protein amino-acids supplies an index of genetic diversity. Stated another way, the average number of amino-acid differences detected in comparisons can be expressed through a scale of 'genetic distance'. We c a n generally regard proteins as a random sample of all the genes of an organism. If we can likewise estimate the total number of genes in a genotype, we can, by examining the proportional protein differences, obtain a rough estimate of the number of genes by which two organisms, or two species (or subspecies, populations, etc.), differ (Ayala, 1976; Lewontin, 1974). For example, electrophoresis has indicated to us that man is more closely related to chimpanzees and gorillas than to orangutans and gibbons--a finding that has been confirmed by the related technique of serology, that examines the reactions of proteins with antibodies. Electrophoresis also allows us to determine that two superficially similar species of Drosophila actually differ in thousands of their genes, perhaps in 3 0 - 4 0 percent of the total number. This means that while two species (as two organisms) may be very similar in phenotypical traits, their genetic makeup can be quite different. True, electrophoresis offers us only partial and approximate measures of genetic variability. In some respects, it does no more than confirm what we have already suspected. By comparing protein concentrations in insects, fishes, amphibians, reptiles and mammals, we find that sibling species (species whose appearance suggests that, to all intents and purposes, they are alike, though separated by reproductive isolation)reveal a genetic distance of 0.1-1.5, while congeneric species (other species within the same genus, with outward appearance dissimilar) reveal a distance of 1.15-3.3. When we look, however, at two key indicators of quantitative variability, viz. polymorphism and heterozygocity, we find that an average value for plants is 17 percent, for invertebrates 13.4, for man 6.7, for vertebrates in general 6.6, for reptiles 5, and for birds less than 5. Least variability appears among large marine vertebrates (notably porpoises, tuna fish, and 108
probably the great whales); an intermediate amount among temperate-zone species; and most among tropical species. Among plant species of the tropics, we find that 'habitat generalists' typically reveal greater variability than 'habitat specialists'. Electrophoresis also helps us to assess the genetic values of endemic species. Endemics can reveal a high degree of genetic variability. At the same time, this characteristic is often correlated with a number of factors that make endemics unduly vulnerable to extinction, viz. highly specialized biotopes, easily disturbed biocoenoses, and microclimatic niches. These findings are preliminary and approximate, so long as electrophoresis, like related techniques, remains a 'youthful' investigative tool. But the findings carry all manner of critical implications for conservation. They tend to confirm that tropical biomes feature exceptional amounts of genetic diversity, both within species and among species. They also suggest that endemic species deserve special attention from conservationists, on the grounds not only of their localized distributions and specialized lifestyles, but on grounds of their high degrees of genetic variability. Let us now move on to a related question of critical minimum size for genetic reservoirs. Despite its significance to conservation, the issue of genetic viability of small populations remains, in the main, little understood. Nevertheless, we now have a few guidelines. On the positive side, we know that certain species maintain a good part of their genetic diversity even after their populations have been grossly reduced. A few tree species retain 90 percent of their genetic potential even after their total numbers have been depleted to a final 10 individuals (by contrast with the case for most tree species, that reveal the same level of diversity only if several thousand individuals remain extant). Of the collection of rubber-tree seedlings brought out of Amazonia by Henry Wickham a century ago, only 22 seedlings reached Malaya, yet this small 'founder stock' was sufficient to establish the plantations from which today's rubber industry has developed across several hundred thousand square kilometres of Southeast Asia. By and large, populations of woody plants seem to contain higher levels of genetic variation than do populations of herbaceous species. Furthermore, predominantly out-breeding species maintain higher levels of intrapopulation genetic variation than do predominantly in-breeding species. What, then, shall conservationists determine with regard to minimum genetic reservoirs for The Environmentalist
plant species? With respect to tropical-forest plants, that comprise a r o u n d 45 p e r c e n t o f all plant species on earth, we have a m o d i c u m o f e x p e r i e n c e - - s p a r s e in the e x t r e m e , b u t b e t t e r t h a n nothing. If, on average, a tropical-forest plant maintains a b o u t 1 0 - 2 5 individuals in every 100 hectares, then, to maintain a stable population o f some 2 0 0 0 - 1 0 000 individuals, we need to t h i n k in terms o f a genetic reservoir o f 1 0 0 1000 square k i l o m e t r e s (Poore, 1976). Only a few tropical-forest preserves are as big as 1000 square kilometres. A d i f f e r e n t set o f guidelines are required for animal species. By reasons o f space, we c a n n o t go into this f u r t h e r t o p i c here. The i n t e r e s t e d r e a d e r is r e f e r r e d to the literature, n o t a b l y Bonnell and Selander, 1974; C o n w a y , 1980; Flesness, 1977; Frankin, 1980; Ralls et al., 1979; and Soule, 1980. In conclusion, we might consider a f u r t h e r d i m e n s i o n to the challenge o f maintaining genetic diversity a m o n g s p e c i e s - - a n d within species. This is perhaps the m o s t i m p o r t a n t c o n s i d e r a t i o n o f all, in light o f o u r responsibility for maintain-
ing e v o l u t i o n a r y processes, F r o m a s t a n d p o i n t o f m e r e l y safeguarding a species' genetic variation, we can s a y - - t o cite Franklin's splendid illustration ( 1 9 8 0 ) - - t h a t o n e e l e p h a n t m a y be as good as another. But we certainly c a n n o t say the same if o u r aim is to conserve the e l e p h a n t (Fig. 7(a) and (b)) r a t h e r t h a n to ensure the survival o f elephant-like descendants: " I f we are c o n c e r n e d with preserving the precise p h e n o t y p e o f a species, r a t h e r t h a n a p h y t o g e n e t i c line in which we allow c o n t i n u e d e v o l u t i o n a r y change, o u r strategies will be very different... When y o u have seen one r e d w o o d , y o u have n o t seen t h e m all."
Economic Values E x t i n c t i o n o f species c o n s t i t u t e s an irreversible loss o f u n i q u e natural resources, n o w and forever. O f the small n u m b e r o f species already investigated for their e c o n o m i c value ( r o u g h l y 10 percent o f all species superficially screened for any value, o n l y one p e r c e n t systematically screened for several values), a considerable p r o p o r t i o n make c o n t r i b u t i o n s to agriculture, medicine,
Fig. 7(a) and (b). African Elephant. The African Elephant still totals well above one million individuals. But because of the ivory trade and habitat loss, its numbers are declining rapidly. As its populations become split off from one another, foreclosingany further prospect of gene flow, there will start to be some genetic impoverishment of remaining representatives of the species. To date, we know all too little about the problems associated with genetic decline in the wild--though this is almost certainly a key factor in long-range conservation campaigns. (Photo Credits: Norman Myers.) Vol. 3, No. 2 (1983)
industry and bio-engineering. In light of experience to date, it seems a statistical certainty that the earth's spectrum of species potentially offers many utilitarian benefits to society. In fact, species could rate amongst society's most valuable raw materials with which to meet the unknown challenges of the future. As a measure of what species already contribute, it is estimated that the American economy benefits from genetic resources to the extent of at least $30 billion per year, possibly a good deal more (Myers, 1983). Among urgent questions to be asked are the following, by way of illustrative examples: In which sectors of the plant kingdom are the 80 000 known edible species to be found? Are 'promising candidate' species concentrated in particular geographic localities, which will allow conservation efforts to be applied with maximum impact? Does something similar apply to genetic reservoirs that supply germplasm for existing c r o p s - - a n d of plant species and strains in question, how many are already endangered, or likely to become threatened within the next few years? In short, how far can conservationists direct their main efforts to certain limited sectors of the plant kingdom? Is it possible and advisable to give special attention to, for example, the 13 000 species of Leguminosae? Many of the most important economic plants on earth are legumes, e.g. alfalfa, beans, peas, peanuts, soybean and acacias; and many leguminous species can support other crop plants through their ability to fix nitrogen, thus eliminating the need for farmers to apply ever-more costly chemical fertilizers. As for medicine, wild species already supply many drugs and pharmaceutical preparations. For instance, a leading source is the organic alkaline compounds known as alkaloids. These exceptionally valuable compounds, found hitherto in almost 20 percent of plant species investigated, include tumour inhibitors, strychnine, narcotics, local anaesthetics, and cardiac and respiratory stimulants. To date, only around 2 percent of earth's 300000 flowering plant species have been screened for alkaloids, producing nonetheless over 1000 forms. A key question is: Which plant groups contain greatest varieties of alkaloids? Certain families, e.g. the Rosaceae and the Saxifragaceae, are known to harbour large concentrations of glycoside alkaloids (useful against cancers), thus illustrating a common evolutionary base for these secondary metabolites. Does something the same hold good for other plant families? Or for certain genera within the two families named? Are any of these categories of plants under greater threat than others? 110
Which plant groups offer promise as sources of steroids, particularly for contraceptive and abortifacient materials? What findings are so far revealed by the investigations of the World Health Organization's Reproduction Research Unit, seeking among the plant world for a safe and effective 'pill'? A supplementary approach is to ask whether particular areas are likely to feature high concentrations of species with probable benefit to medicine. Borneo, for example, is characterized by exceptional floral diversity, with roughly 10000 species, many of them endemics--and at least 4 percent of them could prove valuable to medicine, notably the Apocynaceae, Asclepiadaceae, Connaraceae, and Menispermaceae. The Borneo habitats of these families thus deserve special attention. Similarly, certain forest areas of Costa Rica have been found unusually rich in cancer-inhibiting drugs, and likewise merit priority treatment. Can the same be said of other areas, and with respect to which categories of species? In addition, an entire physiobiotic realm, the oceans, looks likely to offer many genetic resources in support of medicine. Yet the oceans, and especially those areas where the great bulk of marine life exists, viz. coastline ecosystems, are coming under rapidly increasing threat from pollution among other disruptions. To cite but one example, a Caribbean sponge yields a compound that looks likely to supply a breakthrough in the treatment of diseases caused by viruses, much as penicillin has achieved for diseases caused by bacteria; as a result of this widelyacclaimed discovery, there is now prospect of finding cures for a wide range of viral diseases, including the common cold. Other marine species in the Caribbean might supply further compounds of unusual promise for medicine. Yet the Caribbean, as a semi-enclosed sea with growing amounts of industry along its shores, notably oil refining, plus oil extraction in several sectors of the sea itself, is highly susceptible to pollution, the latest example being the Mexico oil-well blowout. Many wild species are utilised for a range of industrial products. As technology advances in a world growing short of virtually everything except shortages, industry's need for new raw materials will grow ever-more rapidly. Certain plants may soon serve as sources of energy, by virtue of their capacity to produce hydrocarbons like oil instead of carbohydrates like sugar. A number of trees from the Euphorbia family, at least 20 tested to date, produce significant amounts of a milk-like sap, latex, actually an The Environmentalist
emulsion of hydrocarbons in water. Generally similar to hydrocarbons in petroleum, Euphorbia hydrocarbons are superior in that they are practically free of sulphur and contaminants found in fossil petroleum. While Euphorbia species seem to be especially suitable for 'growing gasoline', some 3 0 0 0 0 species o f plants produce latex, spanning several families. Despite the marked importance of these families, next to no steps have been taken to assess the survival prospects o f their component species: where are they located, what is happening to their habitats, which species offer most potential and yet are in worst shape? A second example of industrial applications concerns lichens. A good number o f earth's 18 000 lichens, notably those that grow on tree trunks and walls, are exceptionally sensitive to traces o f heavy metals and sulphur dioxide in the atmosphere. Yet it is precisely this factor that is causing lichens to disappear in several industrialized contries. Again, a number of urgent questions need to be asked. Which categories of lichens can best serve the role of environmental monitors? Which lichens are most endangered? How far do these two groups overlap? This review throws up a number of planning implications for conservation. For instance, how far can we tackle the particular case of threatened plants through cost-benefit analysis? To answer this question, let us briefly look at plants as sources of anti-cancer materials. During the past 25 years, two US federal a g e n c i e s - - t h e National Cancer Institute and the Economic Botany Laboratory, both located in the environs o f Washington D . C . - - h a v e mounted a major programme to track down those categories of plants that offer most promise for anti-cancer materials. This research programme represents perhaps the most extensive and methodical effort to investigate species for particular b e n e f i t s - - a l t h o u g h , due to the scale and complexity o f the task, the programme has been less than comprehensive and systematic. By 1980, the programme has investigated some 35 000 plant species, selected from some 6000 genera. It appears that roughly one species in 10, and one genus in four, reveals anti-cancer activity (Barclay and Perdue, 1976; Cordell, 1978; Douros, 1976; Douros and Suffness, 1980; Duke, 1980; Suffness and Douros, 1979). Of the thousands o f extracts with ostensible promise against cancer, only about 15 have survived numerous laboratory tests and clinical trials; and only two compounds, vincristine and vinblastine, both from the rosy periwinkle, have reached the Vol. 3,No. 2 (1983)
status of 'superstar drugs'. Nevertheless, and as a measure of how far a single plant species can contribute to our welfare, global sales of vincristine now total around $100 million a year (Brooke, 1978; International Marketing Statistics, 1981). How should scientists best proceed in order to give themselves best chance of identifying key candidates among Earth's abundance of plant forms? One strategy lies with a geographic approach. Certain zones and localities ostensibly prove better bets than others. For example, tropical and sub-tropical climes show a higher percentage of activity, sometimes a tenfold greater proportion, than plants from temperate zones, which again are higher than plants from boreal zones. The explanation for this finding could lie with the theory that the tropics feature pronounced ecological competition, the temperate zones less, the boreal zones less still (Douros and Suffness, 1980; Suffness and Douros, 1979). Among tropical biomes, does any one present exceptional potential? Fortunately, there is a strongly positive response to this key question: tropical moist forests (Myers, 1980; Raven, 1981). This one biome appears to be in a class o f its own as a source of anti-cancer c o m p o u n d s not only because of the abundance and diversity o f its plant taxa, but apparently because of the biome's evolutionary ecology which has thrown up the highest percentage o f alkaloid-bearing plants, plus the highest yield of alkaloids, o f all earth's biomes (Levin, 1976). Whereas 3000 plant species worldwide are known to possess anti-cancer properties, and at least 70 percent of them occur in the tropics, a further 70 percent occur in tropical moist forests. Thus one can speculate on the concentrated stocks of anticancer materials that ostensibly await exploration in this small sector o f earth's land surface, a mere 7 percent. If Latin America's forests alone contain 9 0 0 0 0 plant species, they could well contain 9000 species with anti-cancer activity, some 45 of which could offer major interest to cancer research, and three of them could ultimately prove to be sources o f 'superstar drugs'. Not surprisingly, the National Cancer Institute and the Economic Botany Laboratory believe that the widespread elimination of tropical moist forests could represent a serious setback to the anti-cancer campaign. Curiously enough, the second most promising group of ecotypes comprises those that are at the opposite end of the climatic spectrum, viz. arid zones. The high potential of these zones is thought to be due to the tendency for arid-zone plants, in response to environmental stress and 111
'biological warfare', to produce toxins of many novel k i n d s - - a n d it is these unusual compounds that can kill cancer cells. Moreover, arid-zone plants represent small and isolated families, with highly divergent biochemistries; many of them occur in monotypic genera and families, again leading to unusually distinctive botanochemicals (curiously, however, species from within the same genus tend to be similar in their chemical constituents, with little variation among their secondary metabolites). By virtue of their 'oddball' characteristics, arid-zone plants offer outstanding promise for anti-cancer materials. For related reasons, aridzone endemics are likewise of high interest to cancer researchers, not only (indeed not so much) because they are unavailable elsewhere, but because they tend to feature unusual medicinal properties in their botanochemical makeup. So potent and diverse are the botanochemicals of arid-zone plants, that if one were to analyse I00 plants species from Egypt and 100 from Brazil, the Egyptian plants would be likely to reveal five times more anti-cancer capacity than the Brazilian ones (Duke, 1980). On a country-by-country basis, we have a few clues, based upon a small-scale screen of an unevenly distributed proportion of plant species (Barclay and Perdue, 1976; Duke, 1980). Mexico and Central America reveal 3.8 percent activity (Belize 4.9 percent and Costa Rica 5.6 percent), the West Indies 3.6 percent, Puerto Rico 5.6 percent; Nigeria 7.5 percent, Ethiopia 8.3 percent (tropical Africa as a whole, only 4.1 percent); Pakistan 17.6 percent, Sri Lanka 12.4 percent, and India 4.8 percent; Papua New Guinea 7.8 percent, Philippines 5.8 percent, and Samoa 5.7 percent; Israel 6 percent, and Turkey 5.3 percent; Netherlands 4.6 percent and Italy 4.3 percent; and the United States 2.9 percent. For the sake of some rough cost-benefit analysis, what are the costs of the research programme to track down plants with anticancer materials? The combined budgets for anti-cancer work on the part of the National Cancer Institute and the Economic Botany Laboratory have amounted to only $4 million per y e a r - - a total that is to be viewed within a context of the entire anti-cancer campaign in the United States, running at just over $1 billion per year. As for the costs of cancer to American society each year, a rough estimate places the figure at $30 billion--a figure that ignores or denigrates 'externalised' costs such as workers' compensation payments (Suffness and Douros, 1979). While a figure of $30 billion may seem high, we should recall that cancer is the only 112
major fatal disease whose incidence is increasing. A person born today faces a 27 percent probability of contracting cancer by the age of 85, by contrast with about 20 percent for a person born in 1950. Viewed in this manner, it would be an exceptionally cost-effective gesture for American society to allocate greater expenditures to the collection and screening of anti-cancer materials from wild species of plants and animals. The market for anti-cancer drugs is expanding worldwide at around 25 percent per year, and is projected to reach $2 billion by the mid-1980s (Brooke, 1978; International Marketing Statistics, 1981). By the same token, of course, it would be an unusually sound investment for society as a w h o l e - - n o t just the United States, but the entire community of n a t i o n s - - t o assign far greater priority to safeguarding the ecosystems of those plant categories with exceptional potential for anti-cancer materials--as indeed for all plants that ostensibly offer economic benefits to humankind. Cultural and Aesthetic Values
Certain species are culturally significant. Examples include the wild horses and asses, and the cameloids, as relatives of man's main beasts of burden. Certain species are beautiful or spectacular: many birds clearly qualify, as do the tiger, the giraffe, and the seals, among many others. Certain species are unusual, for example the orangutan, the rhinos and the kangaroos. Certain species possess marked appeal for their 'cuddly attributes', for example the koala bear, the giant panda and the chimpanzee. A number of species possess symbolic significance. The bald eagle is a case in point for the United States, as is the Phifippines eagle (Fig. 8) for the country after which it has just been renamed. The great whales are of special symbolic value. To the public, the whales represent creatures of unique size, intelligence and lifestyle. To the conservationist community, they represent exceptional importance: if we cannot win the battle for the whales, does that not say something about the entire save-species campaign? Many of these 'values' can be characterized as anthropomorphically derived. In a mandominated world, they are presumably no worse for that, insofar as man appears to be the measure of all things. Indeed these cultural and aesthetic values occupy a legitimate, as well as a necessary, place in the conservationist hierarchy of factors to be evaluated in comparative terms, alongside the biological attributes, genetic factors, etc., already dealt with above. Although it is difficult The Environmentalist
for their cause. But how many persons have heard of the Spanish Imperial Eagle, of which only 150 or so are left? Or the kakapa, with fewer than 100 remaining in New Zealand? Or the Mauritius kestrel (Fig. 9), now probably down to its last 20 survivors? And who would miss the Kauai Oo, fewer than 10 of which hang on in Hawaii? Among the ten most endangered species in the United States are the birdwing pearly mussel, the lotis blue butterfly, the Houston toad, and the clay-loving phacelia: how many o f the public have even heard of these creatures, let alone would miss them? Further, how many people realize that their daily welfare is enhanced, in all manner o f ways, by the material contributions o f wild creatures that share the earth with us? In Nevada, bumper stickers read 'Happiness is a desert pupfish': it is easy enough to support the pupfish when
Fig. 8. Philippines Eagle. Formerly k n o w n as the Monkey-eating Eagle, and now renamed the Philippines Eagle, this bird, in parlous state because of destruction of its forest habitats, has become a symbol of conservation campaigns in the Philippines, and is probably worthy, for that reason alone, o f the large a m o u n t s o f m o n e y spent on it. (Photo Credit: Vollmar/WWF.)
to balance off aesthetic appeal against ecological function (how to compare the cheetah with some obscure spider?), it is important to tackle this question. A number o f cultural and aesthetic factors can be subsumed under a catch-all heading, 'public opinion'. No matter how 'unscientific' this phenomenon might appear as a factor in savespecies campaigns, public opinion counts. After all, it is the general public that produces funds for citizen-activist groups, and that ostensibly approves budgetary allocations for governmental support o f threatened s p e c i e s - - a n d that (so the conventional wisdom runs) 'chooses', via its elected representatives, between e.g. the snail darter and the Tellico Dam. It is a pity that only the merest fraction of the world's threatened species possess large soft eyes, an inspiring demeanour, and lustrous coats. Of these fortunate few, only a trifling proportion again are well enough known to the public to excite general interest. The tiger, the chimpanzee and the blue whale can mobilize public support Vol. 3, No. 2 (1983)
Fig. 9. Mauritius Kestrel (Falco punctatus). Reduced to just a few individuals, the Mauritius Kestrel clings to existence by virtue o f considerable sums spent on it each year. Insofar as we m u s t question w h e t h e r its gene pool is still sufficiently large to ensure its indefinite survival, and to the extent that it is closely related to the African Kestrel that thrives in its m a n y thousands on the continent, we should perhaps start to ask whether this island unfortunate still deserves the monies that could be p u t to ostensibly more productive use in support of other threatened species. (Photo Credit: Willie Newlands/WWF.)
the 'opportunity costs' of its habitat's survival impinge on the prosperity of a handful of ranchers. But when the snail darter is represented (or mis-represented) as taking away the jobs of thousands, the darter is not everybody's cutsie creature crying out for a helping human hand. Whether we like it or not, then, public opinion is a factor that has to be reckoned with when we formulate our save-species campaigns. Fortunately, thanks to the work o f Professor Stephen Kellert of Yale University (1980), we now have a better idea of how the public perceives endangered wildlife, and how public support could be stimulated to put more muscle behind threatened-species programmes. With regard to a range of issues, most Americans would apparently prefer to trade off development activities, housing, even jobs, against protection of wildlife--provided the species in question are o f the right sort. US citizens strongly support protection for the bald eagle, the mountain lion, the American crocodile, and endangered butterflies. They are less than enthusiastic, however, about a threatened snake or a spider, or a little-known fish. So far as Kellert can determine, public support for endangered species depends on questions such as an animal's attractiveness, its biological relationship with humans, the reasons for its endangered status, its economic value, and its importance in American folklore. This suggests that public opinion can be mobilized if the species at issue possesses symbolic value (for example, the bald eagle), more readily than if the species is a cold-blooded and scaley creature that has low public profile, e.g. a fish. This is presumably on the grounds that symbols are important to the community: when much else appears to be failing us, symbols inspire us with their enduring images. Or, to interpret the value another way, a symbol can serve a unifying function. To Americans, the Bald Eagle may epitomize their heritage in the way that the Statue of Liberty d o e s - - a n d thus it is to be safeguarded with just as much vigour. The difficulty arises when we reflect that the Bald Eagle species is scattered among many thousands of individual entities, and so is far less amenable to protection than is a localized, stationary entity such as a statue. As for invertebrates, being the creatures that constitute the great majority o f all species, Kellert found that they do not figure much at all in Americans' understanding of the threatened species problem. Interestingly enough, a majority o f citizens favour increased government funding for wildlife management, plus sales taxes on wilderness114
associated equipment such as camping gear, also on bird-watching supplies. True, these revenues would presumably be intended for US wildlife programmes. But the sectors o f American society that most strongly support threatened species, viz. better educated people, high-earning people, and professionals, will presumably come out in favour of two recent initiatives in Congress to raise funds for international wildlife, viz. the bills of Senator John Chafee and Congressman Udall. It is also relevant to note that whereas a Time Magazine survey in 1977 indicated that the World Wildlife Fund ranked only fourth among international causes that citizens support, after UNICEF, the International Union Against Cancer and the International Red Cross, a 1979 re-run of the survey revealed that the World Wildlife Fund had moved ahead of the International Red Cross. Two examples can illustrate the positive benefits of public opinion at work in support of threatened species. In Australia, the hairy-nosed wombat in South Australia was reduced, by 1967, to only three remaining habitats. One of these relict areas was to be sold by its owner for agricultural purposes. Local citizens responded by a speedy fund-raising campaign that produced the necessary $18 000 in only five w e e k s - - a n d before the campaign ended, they managed to raise $30000. Local citizens thus made a clear and direct expression of their preference that the habitat remain for the wombat rather than be converted to exclusive-use cropland (Sinden and Worrell, 1979). Of course other citizens of Australia, and o f the world, benefited, at no cost, from this initiative on the part of local citizenry. The second example lies with the tiger. It is often proclaimed that the tiger, by virtue o f its powerful appeal in the public eye, can extract conservation funds from the pockets o f citizenry for its own survival--which means that the safeguard efforts on behalf o f the tiger, i.e. the setting aside o f forest ecosystems in Asia, thereby protects habitats for a whole c o m m u n i t y of other species, most of which do not possess a fraction of the tiger's public appeal. This argument should not, however, be pursued too far. A tiger's forest ecosystem tends to be a climax ecosystem, that is to say, an ecosystem that is in its furthest present stage of development. Because o f the interdependency relationships o f many organisms in tropical forest ecosystems (see paragraphs on 'keystone mutualists' in section on Biological Attributes above), there is need to maintain patches of successional vegetation in forest preserves as well (Ewel, 1980; Gilbert, 1980). This appears to apply especially to The Environmentalist
invertebrates. An invertebrate species with distinct juvenile and adult phases in its life-cycle may require fruits from both successional-forest and mature-forest plants at different stages o f the year. Other species require clearings in the forest. In very general terms, it appears that a forest preserve should feature up to one tenth of its area in successional form. Still more symptomatic o f the public appeal offered b y a few species is the California condor. With a spectacular wingspread of over three metres, the bird can soar to 3000 metres, and live to be 35 years old. A majestic sight (on the few occasions when it reveals itself to human eye), the condor has excited a curious mystique in the public's mind. Presumably this is due not only to the condor's super-spectacular appearance, b u t to its plight as one of the most endangered bird species in the United States, if not on Earth. Although the largest bird in North America, the condor has one o f the smallest populations. By 1980, the species' total had declined to around 30 individuals or so, a mere 8 or 10 of which are of breeding age. (There is also one captive bird in the Los Angeles Zoo.) Despite complete protection for the birds, and the isolation o f their nesting areas in high-cliff caves, the species apparently pursues a slow, and inexorable?, march toward extinction. How far should we go to protect a creature that is dismissed b y some observers as an evolutionary 'geriatric case'? Should we assume that we do not yet know how to determine when a species is inevitably declining through its own natural accord, and try to save the creature? The second option is currently being pursued, at a cost o f some $25 million spread over 40 years. (In addition, there are social costs, related to petroleum deposits in the bird's habitats that cannot be exploited; these costs can be estimated at $3 million per year (Bishop, 1978).) The preservation programme, one of the most expensive endeavours ever undertaken, offers, according to the Fish and Wildlife Service, only a 50/50 chance of s u c c e s s - - a n d we may not k n o w whether the investment is paying o f f for at least another two decades. Despite these reservations, however, the effort may represent a sound use o f conservation funds, in view o f the condor's symbolic value. Suppose the bird were allowed to slip quietly into oblivion, an extinction that could be construed as part natural, part man-caused. Would the public then protest to the effect that if conservationists cannot save the condor, what can they save? In other words, does the bird perhaps Vol. 3,No. 2 (1983)
possess 'public opinion' value way beyond the value of its own intrinsic worth? If our bestjudgement assessment tells us that this is the case, then we should go ahead with a sizeable outlay o f conservation funds in support o f this single species, despite its doubtful prospects of survival. The decisions about the condor are difficult in the extreme, largely because the values at stake cannot be quantified. So, at least, the argument runs. But one exercise in quantification could illuminate the i s s u e - - a n d , to this writer's knowledge, it has not yet been undertaken. An allocation of $25 million to the condor means that a similar sum cannot be spent elsewhere. If the same monies were given over to a preservation plan for one of Hawaii's richer habitats, they might help the cause of several bird species at one time, all of them offering far better chance o f success than the condor (and a Hawaiian project could protect a number of other rare and threatened species, notably plants and insects, at the same time, by contrast with the situation in the condor's habitat). Still more to the point in terms o f the global heritage in species, $25 million spent on the relict montane forests of East Africa, or on the southern strip o f Atlanticcoast forest in Brazil, or on certain localities in New Caledonia, would almost certainly assist several dozen threatened s p e c i e s - - n o n e of which, however, possesses the charismatic image of the condor.
Species and Exceptional-Value Ecosystems As the foregoing has made plain, certain zones are biotically richer, and ecologically more diverse, than others. Notable examples are tropical moist forests (Fig. 10) and coral reefs (Fig. 11). By safeguarding a sector of these biomes, conservationists can accomplish more, in terms of saving totals o f species, than through safeguarding much larger zones in other biomes. The consideration applies especially to tropical moist forests. As a consequence o f these forests' evolutionary ecology, a number of lowland areas feature high concentrations of species, many of them endemics (Prance, 1982). Conservation programmes could profitably concentrate on these localities, on the grounds that they will offer a better return per conservation dollar invested than would be the case for virtually any other areas on earth. A similar approach can apply to other ecological islands. The Sudd Swamp in southern Sudan, being a long-established island of moisture amid a semi-arid region, features an exceptionally rich array of species, many of them endemics. The Sudd's ecosystem is currently being disrupted 115
Fig. 10. Tropical forest in Costa Rica. Tropical forests constitute the single largescale biome to harbour large numbers of species (their biological richness is matched only by coralreef ecosystems, which are much smaller in extent). At the same time, tropical forests are undergoing more rapid and more widespread disruption and destruction than any other biome. It is in these forests that the first great waves of extinctions are starting to occur. (Photo Credit: Janet Barber/WWF.)
by the Jonglei Canal, and entire communities of species could become extinct within the foreseeable future. Many other wetland zones can be identified, deserving varying degrees of priority treatment for conservation. To this extent, then, conservationists can finesse the dilemmas o f priority-ranked species, by directing greater attention to protection of entire communities of species, and protection of entire ecosystems. (This expanded approach is already proclaimed b y conservationists; but it is observed more in principle than in practice, since the great bulk o f efforts of e.g. the Species Survival Commission are still directed at individual species, rather than communities or ecosystems.) Yet even when we pitch our response at the broader-scope level of communities and ecosystems, we are still faced with the same agonizing choices: how do we choose between those communities and ecosystems that would be very appropriate/helpful/important to save, and those which are essential to save--given that we cannot assist the whole lot, due to lack of funds? How would we prepare a hierarchical 116
ranking among, say, tropical moist forests, coral reefs, and tropical wetlands? A difficult decision indeed. Not that the choice need necessarily be presented to us in this perplexing form. Were all conservation resources to be directed at these three ecological zones, as 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 good job on each of the three categories. Alas, that is not the way the conservation world works, and the great bulk o f conservation funds, originating in rich nations o f the temperate zones, continue to be directed at species and habitats in temperate zones, even though this is where the threatened-species problem is not so acute, nor suffering such dire lack of funds, as the tropical zone of the Third World. CONCLUSIONS AND RECOMMENDATIONS
Front and centre, let us recognise the urgent necessity of making choices among threatened The Environmentalist
Fig. 11. Tropical coralreef. Tropical coralreefs present an extraordinary concentration of species, not only very colourful animals and plants, but organisms that offer disproportionately large benefits for modern medicine. Yet in many parts of the tropics, coralreefs are being degraded, sometimes critically, through blasting, pollution etc. (Photo Credit: Norman Myers/Fauna and Flora Preservation Society.)
species. This is not a formidable challenge to be confronted somewhere down the road ahead of us, when we have had a chance to get our act together. It is a challenge that we already cope with right now, by virtue o f the funding-allocation systems that we already e m p l o y - - l e s s than systematic and rational as some o f those approaches are. Ever since the start o f the savespecies movement, we have been making choices between species. The expanded strategy proposed here amounts to no more than an extension of the past, albeit in more methodical manner. The key question is not, "Shall we now a t t e m p t to apply 'triage'?" The question is, " H o w shall we apply triage to better effect?" Regrettably, the term triage tends to raise negative connotations in the minds o f some observers. Yet a triage strategy applied to threatened species would amount, in many respects, to a better approach than that which has generally been practiced hitherto. It would be systematic Vol. 3,No. 2 (1983)
rather than haphazard, and it would help conservationists to make optimal use of their finances and professional skills. Those threatened species that, for biological or economic or sociocultural reasons, present 'the most productive opportunities' for investment o f conservation resources, should clearly come top o f our 'shopping list' of priorities. Equally clearly, oilier species may n o t - - s o far as we can d i s c e r n - - m e r i t such priority treatment. For lack o f adequate conservation resources, and f o r no o t h e r reason, certain species will come pretty far down on a hierarchical ranking o f priorities. Still others will be placed so far down on the list that they will effectively be consigned to a category that we designate "We wish we could do something about them, but to our massive regret we just do not have the means available". This is n o t to say that we consign any species to a rag-bag collection of 'species that are not worth saving'. All species are worth saving: we 117
cannot save them all. No species is without its intrinsic scientific interest. No species is without biological value. No species does not make a contribution o f some sort to its ecosystem. We cannot possibly tell which species may not offer economic potential to society at some stage in the indefinite future. Any species may one day generate aesthetic appeal in ways that we do not yet suspect. Still further justifications may be advanced in favour of any species---any species at all. And as a bottom-line rationale, we can say that no species needs any justification for its survival, insofar as all species, being manifestations of life's diversity on earth, can be considered to possess, ipso facto, a 'right to live'. At bottom, the problem with the triage concept boils down to a question of connotations. While triage is a suitable analogy for analytical purposes, it could prove very damaging to the conservationist cause if it became bandied around in the public arena. It takes at least 100 words to explain the rationale laying behind the one w o r d - - a n d all too many well-intentioned people will latch onto the one word, and not find time to consider the 100 words of clarification. Hence a negative image could quickly be engendered for what is, in principle, a fine analytical tool. To this extent, the word 'triage' deserves to be discarded from the conservationist's lexicon, in favour o f some more positivesounding phrase, such as 'priority-ranking system for threatened species'. The second conclusion, and associated recommendation, deals with the need to build up our information base and to refine our analytic tools so that we can better define the biological attributes, ecological attributes, etc., that pertain to the problem. Hence we should forthwith address ourselves to the task o f collating and interpreting the data we need, from both the natural sciences and the social sciences, to make conservation a predictive science. Thus far, we have scarcely made a start on this daunting task. In fact, and as this paper makes plain, we have hardly begun to define the task in all its main dimensions. Put another way, we cannot be sure that we are asking all the right q u e s t i o n s - - n o t , at any rate, as posed in this paper. But were professional researchers, from both the natural sciences and the social sciences, to set about a coherent exercise o f assembling the information they require, and evaluating it for priority-ranking purposes, we could, within as little as a few years, be pretty certain that we are raising all the correct questions, and we could be generating far more appropriate answers than we have achieved to date. At present, there is not even a 1 18
coordinated effort underway, among the scientific community, to embark on a exercise of this nature and scale. Until such an effort is mounted, conservationists will remain susceptible to the criticism that they have yet to recognise the true size and character of the monster they are grappling with. It is not too harsh to assert that, right now, conservation of species is no more than a fairly refined art. Yet it urgently deserves to become a science, with the analytic techniques, quantification capacities, and predictive powers that characterize a science. Conservationists will continue to be less than certain of their aims and procedures until they can measurably demonstrate that if they do A, the result will be B or C (or some other predictable consequence); and unless they do X, the result will be Y or Z. To cite a practical illustration, conservationists need to know what repercussions will stem from broadscale extinctions of e.g. the Hymenoptera or the Palmae or the Cichlidae. What ecological instabilities are likely to ensue, how will residual communities respond, what homeostatic mechanisms could be triggered, how will vacated niches be filled, how can man adapt or modulate or otherwise manage the process? True, some of the relevant knowledge is already available. But it tends to be fragmentary and scattered at best. Scraps exist in research centres, on university campuses, and the l i k e - but it remains uncoordinated to extreme degree. Nor is it likely to be brought together into a cohesive body of knowledge until there is a formal initiative in that direction. In other words, we possess some bricks that go toward the construction of a discrete discipline of conservation - - b u t they will not be used for the cause o f conservation until some 'conservation architect' comes along to design a framework for a 'discipline' of conservation. Moreover, present rates o f research output indicate that we shall have to wait a long time before we possess sufficient bricks for our structure. This is not because there is not much lifescience research underway, at the level of organisms, species, communities, etc. There is a massive amount of such research going on. But only trifling items are given over to the kinds of investigations we need to build a conservation discipline. The white-tailed deer in North America still attracts hundreds o f researchers each year, to produce further reports to go with the thousands of reports that have already been generated on the c r e a t u r e - - a n d the white-tailed deer, far from being a threatened species, is many times more numerous than it was 200 years The Environmentalist
ago, and c o n t i n u e s to proliferate. By c o n t r a s t , w a y u n d e r one p e r c e n t o f all life-science r e s e a r c h is d i r e c t e d at t h r e a t e n e d species o f a n y k i n d , and o n l y a m i n o r f r a c t i o n o f this a m o u n t is d i r e c t e d at t h o s e generalized biological a t t r i b u t e s t h a t could t h r o w light o n the n a t u r e o f e n d a n g e r m e n t , e x t i n c t i o n , and o t h e r crucial p h e n o m e n a . Let us likewise n o t e t h a t a discipline o f conserv a t i o n should b y n o m e a n s b e c a t e g o r i z e d as p r i m a r i l y an affair o f t h e life sciences. T h e r e w o u l d n e e d to be at least e q u i v a l e n t i n p u t f r o m the social sciences, n o t a b l y f r o m r e s o u r c e economics, e n v i r o n m e n t a l law, m a n a g e m e n t s y s t e m s and political science. A third c o n c l u s i o n and r e c o m m e n d a t i o n lie w i t h a shift in ' p h i l o s o p h y ' o f save-species conservationists. T h e s e activists could well e x p a n d t h e i r erstwhile a p p r o a c h b y t a k i n g m o r e explicit a c c o u n t o f all species and their needs. T h e s c o p e o f save-species activities should n o t be r e s t r i c t e d to t h o s e species, o r c o m m u n i t i e s o f species, t h a t are a l r e a d y r e c o g n i s e d as t h r e a t e n e d . R a t h e r it should e n c o m p a s s the entire a r r a y o f species on Earth, w i t h a view to d e t e r m i n i n g w h i c h c o m m u nities and categories o f species are n o w in t r o u b l e , o r s e e m likely to r u n i n t o t r o u b l e w i t h i n the f o r e s e e a b l e future. This will entail a s y s t e m a t i c ' c h e c k i n g p r o c e d u r e ' right across t h e species s p e c t r u m , analysing e a c h s e g m e n t o f the s p e c t r u m f o r its resilience in face o f m a n - i n d u c e d disruptions, traits o f p r o n e n e s s to s u m m a r y e x t i n c t i o n , and the like. As a result, n o c a t e g o r y o f species will start to e n t e r an ' e n d a n g e r m e n t z o n e ' w i t h o u t its plight b e i n g r e c o g n i z e d a h e a d o f time. Finally, a b o t t o m - l i n e c o n c l u s i o n and r e c o m m e n d a t i o n lies w i t h the t h o u g h t t h a t it is n o longer e n o u g h f o r save-species o r g a n i z a t i o n s to go o u t and seek to save species. E q u a l l y i m p o r t a n t , t h e y n e e d to stand b a c k f r o m the scene, and t a k e s t o c k o f w h a t t h e y are doing. T h e y could well l o o k b a c k o v e r t h e i r p a s t r e c o r d , and c o n s i d e r h o w far it has fallen s h o r t o f exp e c t a t i o n s . T h e y should l o o k to the f u t u r e , and c o n s i d e r h o w far t h e y n e e d to a t t e m p t fresh d e p a r t u r e s . T h e best b e t f o r the f u t u r e n o longer lies w i t h ' T h e s a m e as b e f o r e , o n l y m o r e so'. While the t r i e d - a n d - t e s t e d practices o f the past need to b e massively increased, there is n e e d for s o m e ' n e w - e r a p l a n n i n g ' t o c a t e r f o r the greatly e x p a n d e d challenges t h a t lie ahead. This is n o t to gainsay the e f f o r t s o f the few d e d i c a t e d p e r s o n s w h o have carried the b a n n e r f o r the save-species cause during m o s t o f the period since the m o v e m e n t b e g a n a r o u n d 1950. Without their c o m m i t m e n t and accomplishments, the w o r l d w o u l d b e plainly p o o r e r . T h e i r Vol. 3, No. 2 (1983)
sustained activities in the firing line have h e l p e d to e x t e n d t h e lifespan o f d o z e n s o f species. This said, the t i m e m a y have c o m e w h e n these front-line t r o o p s , w i t h their stalwart activities, n e e d to be m o r e s t r o n g l y s u p p o r t e d t h r o u g h c a m p a i g n planners. With all t o o few c o m b a t resources, and n e v e r having e n j o y e d t h e l u x u r y o f a s c a t t e r g u n a p p r o a c h , we n e e d to m a k e e v e r y bullet a silver bullet. T o p u t the s i t u a t i o n a n o t h e r w a y , could we be reaching a s i t u a t i o n in the save-species m o v e m e n t w h e r e t h e r e are t o o m a n y Indians a n d t o o few chiefs?
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