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The Problem

During the process of creating this web site, I read many books and field guides for documentation. I view field guides as a collection of nature's masterpieces courtesy of natural selection.

During my study I came across this statement in the introduction of the Peterson Field Guide Freshwater Fishes, 1991, p.13:

"Each species on Earth is the product of millions of years of evolution and as such is fine-tuned to its environment. Only a few species (e.g., dog, starling, carp) can long survive the enormous changes in the environment that humankind currently is causing. Unless the human race succeeds in making major changes in its values and lifestyles, conservation efforts now underway can at best only delay the extinction of most of the species on Earth. To conserve the diversity of life, we must reduce our own population, reduce our consumption, and set aside large ecosystems as preserves. We will be able to accomplish those changes only through education and an awareness of the value of diversity."

Ernst Mayr provides in depth thinking in his essay on "The Origins of Human Ethics" in his book Toward A New Philosophy Of Biology, 1988 by presenting ethical problems of our modern mass society:

"The third great ethical problem of our day is posed by the discovery of our responsibility toward nature as a whole. Growth, whether economic growth, populational growth, or whatever other kind of growth, used to rank very high in our value system. Even though certain influential people like the Nobel Prize-winning economist Hayek and the Pope have so far failed to appreciate the danger of overpopulation, I cannot see how it can be ignored any longer. Certain of our societies, like those of China and Singapore, have courageously tackled this problem by a reordering of ethical values. The sooner other societies follow, the better it will be for the ultimate good of mankind.

The dilemma we are facing is the conflict between traditional values and newly discovered values. Let me remind you of the conflict between man's right to unlimited reproduction and to the unlimited exploitation of the natural world, as against the needs of human posterity as well as the right to existence of the millions of species of wild animals and plants. Where is the proper balance between personal freedom and regard for the welfare of the natural world?

The concept that mankind has a responsibility toward nature as a whole is an ethical concept that seems to have originated remarkable late. In recent times Aldo Leopold, Rachel Carson, and Garrett Harden have been particularly articulate in their championship of a conservation ethic or a community ethic. But much of what these modern Americans consider ethically valuable is not for the immediate benefit of the individual and is therefore resisted. And yet if mankind and the world as a whole are to have a future, it will be necessary that we reduce the selfish tendencies in our ethics in favor of a higher regard for the community and for the whole of Creation…Every generation of mankind is the current caretaker not only of the human gene pool but indeed of all nature on our fragile globe.

Evolution does not give us a complete codified set of ethical norms such as the Ten Commandments, yet an understanding of evolution gives us a world view that can serve as a sound basis for the development of an ethical system that is appropriate for the maintenance of healthy human society, and that also provides for the future of mankind in a world preserved by the guardianship of man."

In his book The Diversity of Life, 1993, Edward O. Wilson tells us:

"The raging monster upon the land is population growth. In its presence, sustainability is but a fragile theoretical construct. To say, as many do, that the difficulties of nations are not due to people but to poor ideology or land-use management is sophistic. If Bangladesh had 10 million inhabitants instead of 115 million, its impoverished people could live on prosperous farms away from dangerous floodplains midst a natural and stable upland environment."

Jared Diamond in his book The Third Chimpanzee, 1993 documents the facts of biodiversity extinction and concludes:

"Thus, the claimed extinction crisis is neither a hysterical fantasy nor just a serious risk for the future. Instead, it's an event that has already been accelerating for fifty thousand years and will start to approach completion in our children's lifetimes." He goes on to write in the chapter… "Nothing Learned, and Everything Forgotten?" that: "Even if every human now alive were to die tomorrow, the damage that we have already inflicted on our environment would ensure that its degradation will continue for decades. Innumerable species already belong to the "living dead," with populations fallen to levels from which they cannot recover, even though not all individuals have died yet. Despite all our past self-destructive behavior from which we could have learned, many people who should have known better dispute the need for limiting our population and continue to assault our environment. Others join that assault for selfish profit or out of ignorance… Nor is it true that the average citizen is powerless. There are many causes of extinction that citizen groups have helped scale back in recent years – for instance, commercial whaling, hunting big cats for fur coats, and importing wild-caught chimpanzees, to mention just a few examples. In fact, this is one area where it's particularly easy for a modest donation by the average citizen to have a big impact, because all conservation organizations now have such modest budgets."

In Paul and Anne Ehrlich's book Betrayal of Science and Reason, 1996, they report the findings of a 1,149-page "Global Biodiversity Assessment" study by the United Nations Environment Programme. This is a peer-reviewed document by 1,500 scientists around the world that represents a clear consensus of the scientific community:

"Biodiversity represents the very foundation of human existence. Yet by our heedless actions we are eroding this biological capital at an alarming rate. Even today, despite the destruction that we have inflicted on the environment and its natural bounty, its resilience is taken for granted. But the more we learn of the workings of the natural world, the clearer it becomes that there is a limit to the disruption that the environment can endure.

Besides the profound ethical and aesthetic implications, it is clear that the loss of biodiversity has serious economic and social costs. The genes, species, ecosystems and human knowledge which are being lost represent a living library of options available for adapting to local and global change. Biodiversity is part of our daily lives and livelihood and constitutes the resources upon which families, communities, nations and future generations depend."

The college textbook Evolutionary Biology, 3rd Ed., 1998 by Douglas J. Futuyma in Chapter 25 tells us that the next mass extinction is happening now. None of the mass extinctions of the past were caused by the actions of a single species, but this one is being caused by the human species. Douglas Futuyma goes on to explain:

"If mass extinctions have happened naturally in the past, without humans, why should we be so concerned about this one? Different people have different answers, ranging from utilitarian to aesthetic to spiritual. Some will point to the many thousands of species that are used by humans today, ranging from familiar foods to the innumerable species used by peoples throughout the world for fiber, herbal medicines, and spices; some will note that thousand of species support small industries that cater to tropical fish hobbyists, orchid fanciers, gardeners, and shell collectors; others will cite the economic value of ecotourism(the most important source of income for Costa Rica, for example) and the enormous popularity of bird-watching in some countries. Biologists will argue that among the invertebrates, plants, fungi, and microorganisms are thousands of species that may (as many already have) prove useful as pest control agents or as sources of medicinal compounds (such as taxol, a compound in yew trees that is used for treating cancer) or industrially valuable materials (for example, the polymerase chain reaction, the basis of DNA amplification and a key procedure in biotechnology, uses DNA polymerase from archaebacteria that inhabit hot springs). 'Biological prospecting,' searching for medically or industrially useful compounds in plants and other organisms, already shows promise of developing into an important (and controversial) business.

These utilitarian concerns, however, are only part of the rationale for conserving diversity. Many people (including this author) cannot bear to think that future generations will be deprived of tigers, sea turtles, and macaws. And they share with millions of others, who care little for such taxonomic distinctions, a deep renewal of spirit in the presence of unspoiled nature. Still others, turning entirely away from a human-centered perspective that values nature only for its economic or aesthetic returns, feel that it is in some sense cosmically unjust to extinguish, forever, the species with which we share the earth.

Conservation is an exceedingly complicated topic; it requires not only a concern for other species, but compassion and understanding of the very real needs of people whose lives depend on clearing forests and making other uses of the environment. It requires that we understand not only ecology and other biological disciplines, but also global and local economics, politics, and social issues ranging from the status of women to the reactions of the world's peoples and their governments to what may seem like elitist, if not imperialistic, Western ideas. Anyone who undertakes work in conservation must deal with some of these complexities. But everyone can play a helpful role, however small. We can try to waste less; influence people about the need to reduce population growth (surely the most pressing problem of all) by means of birth control and economic development; support conservation organizations; patronize environment-conscious businesses; stay aware of current environmental issues; and communicate our concerns to elected officials at every level of government. Few actions of an enlightened citizen of the world can be more important."

Many scientists tell us that five major mass extinctions of plants and animals have occurred during the history of life on Earth. The causes of these extinctions have been large momentous events in the physical environment such as climate change -- until now.

In the book Life in the Balance: Humanity and the Biodiversity Crisis, 1998, Niles Eldredge explains the cause of the presently occurring Sixth Major Extinction on Earth.

"In the current wave of mass extinctions, the driving force is biological: a single species, our own, is disrupting ecosystems and driving species extinct all around the world. And yet, some might ask, given what we now know about the role of disturbance in the evolution of new species, why not just let this mass extinction run its course? The answer is simple: new species can evolve – that is true – and ecosystems can be reassembled, but only after the cause of the disruption and extinction is removed or stabilized. For recovery to begin, we humans will have to cease acting as the cause. And eventually we will, but whether through determined action or through our own demise is less clear."

In his 1999 article "Biotic Holocaust," Norman Myers, a British ecologist and environmental economist tells us:

"We are into the opening stages of a human-caused biotic holocaust – a wholesale elimination of species – that could leave the planet impoverished for at least five million years. That's the worst news. The better news is that this horrifying destruction still lies mostly ahead of us. There is time, though only just enough, to slow and stem the process."

E.O. Wilson estimates that primarily because of worldwide tropical rainforest destruction we are losing three species per hour. This rate of loss is probably on the low side. Conservation gurus such as Paul Ehrlich of Stanford University and Peter Raven of the Missouri Botanical Garden estimate that the extinction rate in tropical forests is more like 50-150 species per day.

In the last chapter of his book, Human Natures Genes, Cultures and the Human Prospect , 2000, Paul R. Ehrlich examines the past history and the present condition of human interaction with our natural resources:

"The question of how much and what kind of human alteration of the environment is appropriate, especially in a context of preserving nature's services for future generations, was not widely considered and ethical issue until the 1970s. It deserves our attention because it will almost certainly be and increasingly central issue in the decades to come. Some already think they see an evolutionary ethical explanation of one aspect of environmental disruption. Recall that there is a school of thought that our ancestors were, because of genetic or cultural evolution or both, natural conservationists. In this view, European and American industrial societies should look to the behavior of tribal peoples to learn how to be proper custodians of natural systems. The implication is that the current assault on biodiversity—the greatest extinction crisis in the past 65 million years—would not be occurring had modern people retained the ethics of their hunter-gatherer forebears instead of evolving new ones to suit urbanizing civilizations. As we have seen, however, there is little reason to believe that hunter-gatherer groups evolved automatic resource-conservation behavior, and the degree to which the interests of indigenous peoples today are congruent with effective conservation policies is a matter of debate.

Until recently, people have not paid much attention to the long-term environmental effects of their behavior but rather have focused on the satisfaction of their immediate needs. It appears that like the Inuit, our hunter-gatherer ancestors did not restrain themselves much in the exploitation of environmental resources. They could not afford the luxury of long-term planning. They changed their environments to the degree that their technological capabilities would permit—helping to exterminate many species of large animals at the end of the Pleistocene epoch and, in so doing, changing the biological communities of much of Earth…

Evolving human natures also permitted enlargement of the scale of the human enterprise to the point that it is destroying the life-support systems on which all our lives depend. They made it possible to condemn society to gradual extinction from loss of ecosystem services, to repeat on a global scale the fates of the civilizations of the Tigris and Euphrates valleys, Easter Island, the classic Maya, and the Anasazi. The technological advances combined with lagging social evolution of human natures have caused overpopulation and continuing population growth, overconsumption and continuing economic growth among the rich, and widespread use of environmentally malign technologies. Those problems have been exacerbated by inefficient, inequitable, and often iniquitous social, political, and economic arrangements. All of these factors are already denying another billion or more people a decent life and inexorably depleting the natural capital that sustains civilization. Despite all the good things that have come out of human evolution, one thing is clear to me and to many of my colleagues who spend their time examining that predicament: our evolving human natures may be heading us toward the worst catastrophe in the history of Homo sapiens.

It is not too late for humanity to avert a vast ecological disaster and make the transition to a sustainable society, but the task will not be simple. The required strategic actions are evident. Population growth should be halted and a slow decline begun to a population size that, in a couple of centuries, might be environmentally sustainable. Such reduction toward an 'optimum' population size might also help to ameliorate social problems. Wasteful consumption in rich countries must be reduced to allow for needed growth in poor countries. Fortunately, a reduction in consumption accompanied by an increase in quality of life is technologically feasible. For instance, physicist John Holdren's scenarios, in which the rich become much more efficient and the poor consume more, offer a possible path toward more equitable and efficient patterns of energy use that could close the gap between rich and poor and reduce environmental damage compared with that which will result if current trends continue. We might be able to reach those goals while temporarily supporting the substantially larger human population that is inevitable before growth can be halted. But technological feasibility is not enough. Our sociopolitical systems also must undergo dramatic revision in the direction of increasing equity at all levels if sustainability is to be achieved. They will also have to deal with differences in the cultural attitudes and capabilities of Homo sapiens, which fuel the trend toward ethnic fragmentation worldwide at one level even as economic globalization is occurring at another—contrasting trends that are, at the least, disturbing. The cooperation that will be needed to solve global environmental problems is unlikely to be achieved in a world divided into haves and have-nots and riven by ethnic antagonisms."

In the Society for Conservation Biology's recently published book Conservation Biology Research Priorities for the Next Decade, 2001, Michael Soule and Gordon Orians tell us:

"The continued rapid growth of the human population, combined with increasing per capita consumption of resources, is generating unprecedented demands on Earth's renewable and nonrenewable resources. Three decades ago, the greatest threat to sustainable use of natural resources was believed to be the high rate of use of nonrenewable resources. The impending exhaustion of those resources was expected to drive up prices and create serious shortages of materials. As it has turned out, technology has been remarkably successful in finding substitutes for many nonrenewable resources, reducing demands on their use and extending the estimates of the lifetimes of their effective supplies.

What has emerged instead as being of most concern are serious problems associated with unsustainable use of Earth's renewable resources. Among these vital resources are physical processes, such as rates of soil formation and the capacities of Earth's oceans, fresh waters, and atmosphere to decompose and dissipate wastes generated by human activities. Humans are exerting substantial influences on the major biogeochemical cycles of carbon, nitrogen, phosphorus, and sulfur, and on renewable biological processes, such as the dynamics of populations of Earth's biota, that is, the species whose activities generate the goods and services on which human society depends."

Soule and Orians go on to explain that:

"Conservation science is employed in the service of an ethical goal, the maintenance of Earth's biodiversity...Averaged over hundreds of thousands of years, speciation rates have exceeded extinction rates, with the result that Earth's current biota may be richer than it has ever been…The current loss of species richness among Earth's existing biota is believed to be driven primarily by a striking increase in extinction rates…Indeed, the U.S. Endangered Species Act is fundamentally an ethical statement. It specifies appropriate behavior that is not simply a matter of economic convenience. The combination of this ethical stance with the estimated current high rates of extinction of species gives a sense of urgency to the activities of conservation biologists…In a world where human beings receive more that 99 percent of the developmental aid and charity, it is increasingly difficult to find resources to help the other species with whom we share the Earth…Even though human behavior poses the fundamental threat to biodiversity preservation, only people can act to reduce the threats to Earth's biodiversity."

In his most recent book The Future of Life, 2002 on pp. 59-61, Edward O. Wilson updates the present state of Earth's degraded ecosystems:

"A frightening aspect of the area-species principle is that while removal of 90% of the habitat area allows about half of the species to hang on, removal of the final 10% can wipe out the remaining half in one stroke. In fact, the number of natural habitats reduced to fragments this size or smaller is increasing rapidly all around the world.

The headquarters of global biodiversity are the tropical rainforests. Although they cover only about 6% of the land surface, their terrestrial and aquatic habitats contain more than half the known species of organisms. They are also the leading abattoir of extinction, shattered into fragments that are then being severely adulterated or erased one by one. Of all ecosystems, they are rivaled in rate of decline only by the temperate rainforests and tropical dry forests.

He goes on to tell us:

Of twenty-five "hotspots" on the land—places with the most species at risk of extinction—fifteen are covered primarily by tropical rainforests…Together with the remaining terrestrial hotspots, covered mostly by savanna and coastal sagebrush, they take up only 1.4% of the world's land surface. Yet, astonishingly, they are the exclusive homes of 44% of the world's plant species and more than a third of all species of birds, mammals, reptiles, and amphibians. Almost all are also under heavy assault. The rainforests of the West Indies, Brazil's Atlantic coast, Madagascar, and the Philippines, for example, retain less then 10% of their original cover.

Large numbers of species have already been lost forever from the forest hotspots. Many more are endangered. In a nightmare scenario, battalions of loggers armed with bulldozers and chainsaws could wipe these habitats of the face of Earth in a few months—and with them a large part of the world's biodiversity. On the flip side, it is heartening in compensating degree to realize that by protecting this tiny fraction of the planet's land area, millions of species can be saved for posterity."

In her book The Work of Nature, 1998, noted science writer Yvonne Baskin summarizes the work of hundreds of scientists around the world in the project SCOPE(The Scientific committee on Problems of the Environment). She writes:

"Our oldest faiths and deepest symbols reflect a primal connection to the natural world, to a living planet that long ago imprinted on the human consciousness a cyclic sense of death and decay, rebirth and renewal. We do not question that flesh and bone and leaf litter will decay to dust, that seeds will sprout season after season and find renewed nourishment in the soil, that rivers can flow endlessly without running dry, that we can breathe for a lifetime without depleting the air of oxygen. Despite our fascination with other worlds and our hopeful probing of outer space, we've found no other planet where any of these things are true. What humans have not fully appreciated until recently is that these services are the work of nature, performed by the rich diversity of microbes, plants, and animals on the earth.
It is this lavish array of organisms that we call 'biodiversity,' an intricately linked web of living things whose activities work in concert to make the earth a uniquely habitable planet. But today, as never before, the species in this web are under siege, threatened by human activities that encroach on their habitats. At the same time, ecologists are increasingly aware that the impoverishment of species—the planet's work force—threatens to erode the basic life-support services that render the earth hospitable for humanity. Indeed, we are approaching a crossroads in time, when the survival and extinction of other species may well delimit the future of Homo sapiens
…Together, plants, animals, and microbes perform an array of vital services. They generate and preserve fertile soils. They break down organic wastes, from leaf litter to feces and flesh, recycling the mineral nutrients, carbon, and nitrogen needed for new plant growth. They absorb and break down pollutants; help maintain a benign mix of gases in the atmosphere; regulate the amount of solar energy the earth absorbs; moderate regional weather and rainfall; modulate the water cycle, minimizing floods and drought and purifying waters; blunt the impact of the seas that batter the land margins; pollinate crops; and control the vast majority of potential crop pests and carriers of human disease…
…If we are realistic about our dreams for tomorrow, our goal is not really 'saving the planet' in some minimalist form, but perpetuating its atmosphere, climate, landscapes, and living services in a state that allows human civilizations to prosper. For that to occur, we need to preserve natural systems that are rich, healthy, and resilient enough to continue to support human welfare and economic activity for the next decade, the next century, and beyond…
…We are in the midst of a biodiversity crisis, and ongoing epidemic of species losses that British conservation scientist Norman Myers has labeled 'biodepletion.' The richness and complexity of the natural world is declining at an ever-accelerating rate, as the earth's burgeoning human population strives for a steadily rising technological standard of living. Natural diversity is being brutally simplified to make way for a dizzying blend of artificial landscapes—villages, housing developments, parking lots, roads, factories, mines, shopping malls, schools, parks, gardens, golf courses, plantations, and croplands.

The biggest threats to the diversity of life on the earth are habitat loss, introduction of alien species into communities, and fragmentation of natural areas caused by bulldozing, paving, plowing, draining, dredging, trawling, dynamiting, and damming. Humans are also plundering natural communities by overharvesting, overgrazing, dousing them with excessive pesticides and herbicides, raining acids and other pollutants onto them, altering the mix of gases in the air, and even thinning the ultraviolet radiation shield on which terrestrial life depends.

Many of these assaults are so massive they wipe out entire ecosystems and disrupt natural processes immediately and directly. For example, draining and filling wetlands or permanently stripping the forest from a watershed instantly eliminates the flood and erosion control, water filtration and purification, and other services those ecosystems provide. Dynamiting a coral reef to extract fish not only destroys the ecosystem, but also exposes the now-unprotected shoreline to storms and so threatens coastal habitats. The impacts of such obvious forms of destruction are immediate and direct. Of equal concern to many scientists, however, is the slower, usually more insidious chipping away of functioning that accompanies the loss of species and impoverishment of their habitats. This erosion of service is harder to spot until it's well underway—easier for developers and government officials and the public to ignore for the moment. After all, what's so serious about losing a few more hectares of land to a few more houses?…
…Extinction rates today exceed by one hundred to one thousand times those seen in the fossil record. Ecologists point out that these rates will be ten times higher if all the species now officially listed as threatened or endangered actually disappear in the next century. With the human population growing exponentially, demanding more land, more food, more resources, millions of species may go extinct before they can be identified and their importance determined.

Skeptics may still argue that massive losses, mostly among obscure species in localized areas of the tropics and other 'hot spots' of high diversity, will have little impact on the human enterprise, especially in temperate regions. Yet the complete extinction of species is only one aspect of the biodiversity crisis. A more urgent but lesser known problem already eroding the structure of communities and the provision of ecological services is the dwindling of numerous plant and animal populations…Ten sockeye salmon struggling up the Snake River into Idaho don't serve bears, bald eagles, or fishermen the way 10 million once did…
…Most of us give little thought to this impoverishment because we are increasingly estranged from the workings of the natural world. Nearly half of us live in urban settings, and that figure is climbing. North America and Europe were more than half urban by mid-century, and the shift of people from the countryside into the cities is increasing across Asia, Africa, and Latin America. By 2025, some 60 percent of the world's population will live in cities, increasingly remote from the natural communities that serve us. We humans traditionally have trouble grappling with issues that we cannot see firsthand. Cloistered in our homes and offices, moated away from wildness by clipped lawns and pavement, nourished on piped water and shrink-wrapped foods, it's easy to lose sight of our reliance on plants, animals, insects, and microbes, as well as the cyclical processes they drive…
…Until recently, the functional role of organisms has seldom been invoked as a basis for conservation. Indeed, ethical and moral pleas for saving species still predominate, bolstered by spiritual traditions in most cultures that include some moral embrace of the life of the planet. At its best, the conservation ethic in the Western world is based on a sense of stewardship, and obligation to protect and care for our only known companions in the universe. Yet for all its noble intent, that moral commitment has proven a slippery foundation for conservation. We continue to degrade and impoverish biological communities at an unprecedented pace.

The reasons for such folly are complex, ranging from economic desperation to simple ignorance or even sheer unconcern about the impacts of our actions. Human societies have a sad history of setting moral burdens aside while acquiring more comfortable or prosperous lifestyles.

Because of this, some ecologists and conservationists have been heartened as the economic benefits of biodiversity have started to become apparent. In recent decades, the direct economic value of the natural world as a source of everything from antibiotics and novel medicines to Brazil nuts, salmon, spices, mushrooms, mahogany, oils, and ecotourist dollars has been touted.

Like the service function of biodiversity, however, this growing emphasis on the practical value of species and natural systems is disquieting to many who harbor a deep affection for the natural world. To some, it seems superfluous on one hand that a creature as marvelous as a moose might have to pin its survival on human self-interest. On the other hand, it hardly seems demeaning to recognize that a moose strongly shapes the character of the very soils and trees in its forest. Such knowledge is likely to raise the general level of respect for less charismatic organisms in the moose's ecosystem, such as fungi, termites, and plankton, which have few advocates, even among traditional conservationists…

…Ecologist have only recently begun to investigate the functional role of biodiversity at all levels, from genes to species, communities, ecosystems, and landscapes. Although the field is young, clearly organisms have profound effects on the ecological processes that supply human beings with food, water, energy, clean air, and other services. It is not just numbers of species but their identity, locations, and interactions that are key to the workings of the earth's life-support systems…
…policymakers tend to behave as though the survival of most non-human organisms is an amenity, one that future generations of humans can live without. Everything scientists are learning about the earth's life-support processes argues against this view. It's time to complement our sense of obligation as stewards of the earth with a somewhat humbler sense of self-preservation, to acknowledge that despite our increasing estrangement from nature, even urban societies are profoundly dependent on it…

…Since scientists know so little about which organisms are critical to maintaining vital ecosystem services, the most prudent course for a survival-minded human species would be to exercise caution and work to preserve all of them. That's a social and economic choice many of us would prefer. Right now, the natural level of diversity is the best proxy scientists have for healthy functioning, and all species losses are warnings of a potential malfunction.

Unfortunately, it may not be feasible to prevent all further losses of biodiversity, even with the best intentions, Only 3 percent of the global land surface is set aside in ;parks and protected areas. More than 95 percent is already under direct human influence, whether plowed, paved, and managed intensively, or sparsely occupied by rural or indigenous peoples. Seventy percent of the globe is covered by oceans and seas, yet only one-quarter of 1 percent of these are formally protected from exploitation and degradation. Nearly all of those protected waters are on the continental shelves rather than the continental slopes and deep seas that cover two-thirds of the earth. With the human population increasing exponentially, our species is hardly likely to take up less space or exploit fewer resources in the future. Now, more than ever, we need to learn how to use lightly and sustainably the natural systems that survive in our midst, from swamps, coastal waters, savannas, and tropical forests to hedgerows and remnant woodlands along urban stream. The more we plunder them, the more likely we are to lower the earth's human carrying capacity—that is, its ability to support Homo sapiens."

  Edward O. Wilson in his book, Nature Revealed, 2006, pp. 618-629 writes:

 “No comfort should be drawn from the spurious belief that because extinction is a natural process, man is merely another Darwinian agent.  The rate of extinction is now about 400 times that recorded through recent geological time and is accelerating rapidly.  If we continue on this path, the reduction of diversity seems destined to approach that of the great natural catastrophes at the end of the Paleozoic and Mesozoic eras—in other words, the most extreme in 65 million years.  And in at least one respect this man-made hecatomb is worse than anything that happened in the geological past.  In the earlier mass extinctions, which some scientists believe were possibly caused by large meteorite strikes, most of the plants survived even though animal diversity was severely reduced.  Now, for the first time ever, plant diversity too is declining sharply.

     ...Organic diversity has remained obscure among scientific problems for reasons having to do with both geography and the natural human interest in big organisms.  The great majority of organisms in the world are tropical and inconspicuous invertebrates, such as insects, crustaceans, mites, and nematode worms.  The mammals, birds, trees, shrubs, and smaller flowering plants of the North Temperate Zone, the subjects of most natural history research and popular writing, comprise relatively few species.  In one area of 25 acres of rain forest in Borneo, for example, about 700 species of trees were identified; there are no more than 700 tree species in all of North America.  Familiarity with organisms close to home gives the false impression that the Linnaean period of formal taxonomic description has indeed ended.  But a brief look almost anywhere else...shows that the opposite is true.

     There is, in addition, a compelling practical argument for attempting a complete survey of diversity...Throughout history, for example, a total of 7,000 kinds of plants have been grown or collected as food.  Of these, 20 species supply 90 percent of the world's food, and just 3—wheat, maize, and rice—supply more than half.  In most parts of the world this thin reservoir of diversity is sown in monocultures particularly sensitive to  insect attacks and disease.  Yet waiting in the wings are tens of thousands of species that are edible, and many are demonstrably superior to those already in use.  In addition, the vast insect faunas contain large numbers of species that are potentially superior as crop pollinators, control agents for weeds, and parasites and predators of insect pests.  Bacteria, yeasts, and other microorganisms, which are also poorly known, and likely to yield new medicinals, food, and procedures of soil restoration.  Biologists have begun to fill volumes with concrete proposals to explore and make better use of diversity.

     The case of natural sweeteners serves as a parable of the potential  of untapped resources among  wild species.  A plant has been found in West Africa, the katemfe (Thaumatococcus daniellii), that produces proteins 1,600 times sweeter than sucrose.  A second West African plant, the serendipity berry        

(Dioscoreophyllum cumminsii), produces a substance 3,000 times sweeter.  The parable is the following:  Where in the wild universe does the progression end?  To cite a more clearly humanitarian example, one in ten plant species contains anticancer substances of variable potency, but relatively few have been bioassayed.  Economists use the expression “opportunity costs” for losses incurred because certain choices were made rather than others.  In the case of systematics—or more precisely the neglect of systematics and the biological research dependent upon it—the opportunity costs are very high.”

  Michael Novacek in his book Terra, 2007, pp.265-343 writes: 

“The natural world as humans have always known it evolved close to 100 million years ago with the appearance of flowering plants and pollinating insects during the age of dinosaurs.  Its tremendous history is now in danger of profound, catastrophic disruption...The conversion of natural terra firma into land for food production and human habitation changed, in a few short centuries, the wild earth so fundamentally that it is virtually impossible to find a crypt of nature untouched by humans...How ironic it is, then, that our activity as agriculturists has devastated Earth's natural environments much more than our selective overkill of some large animal.  I am not a moralist here.  Hunting is not intrinsically bad, nor is farming...I merely report the fact that plant cultivation and animal domestication in combination with unbridled human population growth, consumption, and lack of foresight got us to the dismal place where we are today.  Don't shoot the messenger...

     Croplands and pastures now occupy 40 percent of Earth's land surface...It is estimated that just preceding the advent of human agriculture 11,000 years ago, forests occupied nearly 70 percent of the land's surface.  But in subsequent centuries energetic cultivation thinned out those forest...centuries of land conversion make Asia the continent with the greatest overall loss in forestland...But these historical losses pale in comparison with those caused by the spread of agriculture in response to rapid world population growth during the past two hundred years.  Forests now account for only about 30 percent of the land surface...

     ...The long-ago development of great river settlements along the Tigris and Euphrates of the Fertile Crescent, as well as the growth of river cities in China and Central America, made for expanded populations, and invasion of virgin habitat, and an increased rate of soil erosion.  People moved upriver, cutting down trees and tilling the soils in the mountainous watersheds at the sources of those rivers.  In this newly stripped landscape, heavy and often destructive seasonal rains aggravated erosion...

     ...The next stage in human effect on soils both preceded and accompanied the rise in the use of artificial fertilizers in the 1950's...Not only were bounteous forests obliterated, but their conversion to useful farmland was short-lived because overplowing left little vegetation to hold water.  During the Great Depression era the dust bowls of the Great Plains saw eight years of  'black blizzards' that blocked the sun, buried farms, and drove families from their lands...Worldwide surveys in the 1980's...  showed that at least 40 percent of the world's croplands might be experiencing some degree of erosion, reduced fertility, and overgrazing...soil erosion, the experts agree that there is at least 11 billion tons of human-induced erosion yearly,...representing at least eleven billion U.S. Dollars annually in lost crop production...

     ...In Haiti only 3 percent of the nation's once lush tropical forests remain, and one-third of all formerly productive land,...has been destroyed through loss of topsoil...Demand for food and other resources is very unevenly distributed on a global scale.  Seventy percent of the world's fossil fuels and 80 percent of its chemical products are consumed by only 25 percent of its population.  We are still a world of haves and have-nots.  No one, however, is completely insulated from the environmental problems of our changing landscape.  Those of us who enjoy the often illusionary comforts of a wealthy nation may not have any sense of the daily struggles of a poor farmer in the Sahel, but overconsumption, deforestation, and soil mismanagement are problems that ultimately affect us all.  Those problems relate to the availability of another substance that is inseparable from soil, that life-giving, rare, and hugely threatened commodity—freshwater...

     ...North America's largest aquifer, stretching from South Dakota to Texas, is being depleted at a rate of twelve billion cubic meters a year.  Worldwide, agriculture accounts for 70 percent of the total consumption of freshwater, while industry comes in at about 22 percent, and domestic use at only 8 percent.  Water and soil go together.  You can't have productive soils without water because you can't have organisms without water...The big worldwide gulp that puts heavy pressure on freshwater resources has collateral casualties.  Freshwater ecosystems support a diversity of birds, fish, plants, frogs, turtles, insects, aquatic invertebrates, protists, and bacteria, many of which are highly sensitive to environmental disruption.  But the use of water for irrigation, drinking, waste disposal, damming for reservoirs and hydroelectric power, and the introduction of alien species can mean anything from a serious threat to these habitats to the utter destruction of many species in them.

     This focus on freshwater should not lead one to conclude that other ecosystems are healthy in comparison.  As we have seen, tropical rainforests are being rapidly destroyed, and as go the forests, so go the species that live there.  The simple rate of destruction of these habitats is what gives our current estimates of extinction their heft.  Take away these environments—remember our march to total deforestation of tropical regions may well be complete within this century—and one is left with a projection that between 30 and 50 percent of all species will be gone by mid-century.  The projection is all the more disturbing when we consider that biodiversity is the source of sustenance that makes our lives not only interesting but also livable.  Diverse species are the potential source of tens of thousands of different food products, and thousands of species serve as sources for medicines.  How much more would we have available if we managed forests in ways that allowed for continued mining of their treasures?...

     For example, of the hundreds of thousands of species that are potential sources of food, humans have come to rely on about fifteen hundred plant species, only twelve of which provide three-quarters of the world's food.  Why, then, is maintaining the biodiversity of the original forest so important when restored forests give us boosted amounts of some of its core products?  The answer lies once again in what we call ecosystem services and the many benefits conferred by having a wide variety of species.  Restored forests fail to perform many ecosystem services that original forests can because they usually fail to maintain the original number of species.

     To illustrate, let us return to the very fiber of the modern land ecosystem, the intricate, complex, intertwining of angiosperms and pollinating insects that emerged in the dinosaur age.  Here we confront the worldwide problem concerning those most proficient of pollinators the bees.  We have learned that the first-known fossils of bees are from the mid-Cretaceous, about 100 million years ago, an entry synchronous with the birth date for the full-fledged flowering ecosystem.  The pedigree of the ancient bee that gathered pollen for honey, pollinated fields of Cretaceous flowers, and buzzed the head of T. rex is in deep trouble.  There is currently a crisis in bee management..

     ...animals, prominently bees, pollinate one or more of the cultivars of 66 percent of the world's fifteen hundred crop species and are directly or indirectly responsible for an estimated 15 to 30 percent of food production.  Hence it is easy to see why the most important managed pollinator, the honeybee Apis mellifera, has an estimated annual value between $5 billion and $14 billion in the United States alone.  But this service is diminishing; beekeeping has declined by 50 percent in the United States, possibly as the result of insecticide poisoning, disease, and loss of subsidies..

     ...Perhaps there is a ready insurance policy here.  It comes from our surprisingly strong dependence on wild species of bees for agriculture.  Only eleven out of the estimated twenty to thirty thousand species of bees are used in managed bee farms and greenhouses.  We know little about the nature and magnitude of the pollination services that wild bees perform for crops, but indications are that they are substantial...native bees could provide a pollination service equivalent to that of managed honeybees.  And there was a bonus:  half the native bee species that visit watermelons also visit other crops.  Some of these, such as cherry tomatoes, require lower levels of pollination than watermelons, and it turns out that managed honeybees do not service many of these crops.  The wild bees are doing the work.

     Unfortunately, numerous areas...show a decline in native bee populations because of degraded habitats and the use of pesticides.  Varying agricultural practices produced strikingly different results.  Organic farms near more or less unmolested native habitat could acquire full pollination service for heavily pollinated crops like watermelon without even recruiting managed honeybees.  They profited from a flexibility that comes with the availability of wild species.  But nonorganic farms distant from native habitats could not sustain these crops on native bees alone...

     Pollination has kept our modern land ecosystem going for 100 million years.  Now the loss of natural habitat and their myriad species threatens the very core of what has been built by evolution.  We may be able to get by for a time on artificial systems that mimic the original—managed honeybees and expansive industrialized farms-- but we are already seeing the limits to this emulation.  Opening the door to reviving the system by putting more of natural biodiversity into service could stop the trend, improve crop yield, and save more than a little beautiful land in the process...

     ...once humans established a toehold on several landmasses, they were devastatingly effective in mowing down mammals, birds, and other wildlife.  This began nearly fifty thousand  years ago with the human invasion of Australia and continued with the first colonizers of North America twelve thousand years ago.  Islands were particularly vulnerable, and many of their mass extinction events even more recent.  Human colonization, over-hunting, and introduction of human-borne or domestic fowl-borne disease on Pacific islands starting about three thousand years ago are thought to have promoted the extinction of more than two thousand species of birds.  Many large marine creatures—species of whales, sharks, seals, and turtles—had been nearly exterminated by the early 1800s.  Today massive overhunting, and poaching for food, medicine, and cultural fashion persist in Africa, Asia, and other regions.  The Asian demand for tiger parts for traditional medicines has nearly driven this species to extinction, and that is only one example of the problem.  Recent efforts to control such activity must confront trends established over long history of exploitation and devastation...

     ...Some people think all this talk about the sixth extinction event is simple hyperbole, fueled by hysteria rather than by real science.  They usually issue the following challenge:  it may have been nice to have all these species, but the world is changing in response to human need.  We have to give some things up.  It might as well be a stone fly, a spider, an pond shrimp, a South African...flower, even a rare antelope in a forest in Vietnam, and a gazelle on the plains of the Gobi Desert.  The disappearance of   these creatures, great and small, is regrettable, but we cannot compromise an ever-expanding population and global economy, whose collapse would leave billions to starve.  Moreover, tree farms and other restored green spaces perform many environmental services, including the sustainable provision of a few products, the regulation of water flow, and carbon sequestration.

     They sometimes link this argument with an often ignored fact about the modern ecosystem:  humans have been exterminating its components for forty thousand years.  Much of what we find beneficial and appealing--”natural”--has suffered at least some measure of historical degradation.  What we have come to call natural habitats in our time were already grossly modified by humans centuries ago.  In New Zealand, for example, flightless birds were reduced in a few centuries from thirty-eight to nine species.  David Steadman, who has chronicled the extinction and precipitous decline of birds on Pacific islands, puts it well:  '...the biodiversity crisis is over.  People won:  native plants and animals lost.'  So, the argument goes, this is an inevitable state of affairs, and we should not expend huge resources and energy to protect habitats simply to sustain all their biodiversity.

     This two-part dismissal warrants vigorous response.  All science consists of connecting theories with evidence, and scientists know they must refute a theory if an observation contradicts it.  Scientists are not supposed to claim that they are offering profound truths, yet the following is as close to facts as anything scientists know of, and I label them accordingly:

     Important fact :  What we are experiencing is not just the “normal” rate of extinction, the background rate.  The current extinction rate is soon to be as much as ten thousand times faster than the background rate.  The projected mid-century loss of 30 to 50 percent of species is perhaps not as big a deal as the 90 percent loss at the end of the Permian, 250 million years ago, but it approaches the Cretaceous extinction event 65 million years ago and surpasses in magnitude many extinction events that mark the boundaries of time over the last 500 million years.  Also, the current assault on Earth's biota is not a matter of epochs, millennia, or even centuries, but of decades,...

     Second fact :  Although humans have assaulted the ecosystems of the world for more than forty thousand years, there is no scientific indication that their indefinite exploitation or abuse of the environment will ensure livable conditions in the future.  With the recent acceleration of abuses, we are approaching, indeed may have already crossed, the threshold to catastrophe for much of life on this planet...

     Third fact :  Extinction is irreversible.  Species that die out will never come back.  While humans might accomplish the Herculean feat of  “restoring” destroyed grassland, forest, or rivers, they will never resurrect any extinct species that once lived in those habitats...

     Fourth fact :  This irreversibility of species extinction and its reverberating effect clearly impede ecosystem recovery.  The past provides us with useful evidence.  The “very speedy” post-Cretaceous recovery of some species, among them ferns and some marine invertebrates and microorganisms, took hundreds of thousands of years, hundreds of times longer than recorded human history and nearly as long as the brief span of our species' history.  After the Cretaceous event, key species in the ecosystem, including large plant-eating vertebrates, took even longer, in some cases millions of years.  In anticipating recovery from the current biodiversity crisis, we can take little comfort from what the fossil record shows.

     Fifth fact :  The loss of species is not an event unto itself; it is one event that inevitably leads to others that can threaten ecosystem collapse.  We have learned that the interconnectedness and complexity of ecosystems maximize the impact of species loss.  For example, spiders, which are not humans' most cherished organism but are the most important invertebrate predator on insects in many habitats, are unusually slow and dogged in apprehending prey, and they are particularly susceptible to plant and soil toxins and other products of human intervention.  The endangerment and ultimately the extinction of spider species in many areas, a trend now being explicitly documented by my colleagues at the American Museum of Natural History, will allow the increase of swarms of crop-destroying, disease-carrying insects...

     Sixth fact :  The diversity of species is directly related to the sustenance of human life, not to mention our health, our pleasure, and our happiness.  An analysis of African ecosystems and human population distribution shows that greater biodiversity is directly associated with areas of greater human population.  The two are closely correlated; people need biodiversity.  We use thousands of species of plants and other organisms for food, pharmaceuticals, and raw materials.  The modern land ecosystem depends on plant pollination by insects.  We have seen that bees, including many species of wild bees, pollinate a majority of the world's crop species and are thus directly or indirectly responsible for much of the food we produce for ourselves.

     Gauging the expected level of extinctions by mid-century is a first big step in prognostication.  But we can expect other biological effects, first-order effects,...These include massive losses of population even in species that do survive, accelerated invasions of alien species, progressive depletion and homogenization of biotic communities, global reduction in biomass, and the severe reduction, if not virtual elimination, of some biomes such as tropical forests and coral reefs.

     All these first-order effects have obvious evolutionary consequences:  collapse of species ranges, disruption of gene flow, depletion of gene reservoirs, and the increase in exchange of species between different areas and ecosystems...We might expect and outburst of new species as old ones go extinct and their adaptive zones or niches are vacated.  This is the pattern we see in the fossil record following major extinction events.  What new species might these be?  We have some clues from what we have learned about the uncontrolled evolutionary success of invasive species like zebra mussels and water hyacinths, species that thrive in degraded, human-dominated ecosystems...We might have an Earth dominated by pest and weed ecology...

     ...The twenty-first century may mark the evolutionary dead end of large vertebrates.  As we have seen, much of the devastation that humans have wrought over the past forty thousand years has been unusually focused on big animals.  The survivors of this onslaught now hang on in confined, degraded habitats, with small, isolated populations that maintain only a meager portion of their once enriched gene variation.  We may have already deprived them of the genetic potentials for evolutionary change and adjustment they accumulated over millions of years.  Despite recent conservation efforts, even some of the largest protected areas might be too small to provide a matrix for such evolutionary change.  Particularly vulnerable are bears (especially polar bears), elephants, rhinoceroses, apes, and big cats...evolution and the biota intersect with all the trends in global human society—changes in health, wealth, distribution of resources, trade, government, and societal prerogatives.”

In this excerpt from his  essay “Biophilia and the Conservation Ethic”, 1993, pp.649-652,  Edward O. Wilson elaborates on the problem of humanity's  ignorant disregard for the Earth's natural environment:

     “...There is no question in my mind that the most harmful part of ongoing environmental despoliation is the loss of biodiversity.  The reason is that the variety of organisms, from alleles (differing gene forms) to species, once lost, cannot be regained.  If diversity is sustained in wild ecosystems, the biosphere can be recovered and used by future generations to any degree desired and with benefits literally beyond measure.  To the extent it is diminished, humanity will be poorer for all generations to come.  How much poorer?  The following estimates give a rough idea:

    Consider first the question of the amount of biodiversity.  The number of species of organisms on earth is unknown to the nearest order of magnitude.  About 1.4 million species have been given names to date, but the actual number is likely to lie somewhere between 10 and 100 million.  Among the least-known groups are the fungi, with 69,000 known species but 1.6 million thought to exist.  Also poorly explored are at least 8 million and possibly tens of millions of species of arthropods in the tropical rain forests, as well as millions of invertebrate species on the vast floor of the deep sea.  The true black hole of systematics, however, may be bacteria.  Although roughly 4,000 species have been formally recognized, recent studies in Norway indicate the presence of 4,000 to 5,000 species among the 10 billion individual organisms found on average in each gram of forest soil, almost all new to science,and another  4,000 to 5,000 species, different from the first set and also mostly new, in an average gram of nearby marine sediments.
    Fossil records of marine invertebrates, African ungulates, and flowering plants indicate that on average each clade—a species and its descendants—lasts half a million to 10 million years under natural conditions.  The longevity is measured from the time the ancestral form splits off from its sister species to the time of the extinction of the last descendant.  It varies according to the group of organisms.  Mammals, for example, are shorter-lived than invertebrates.
    Bacteria contain on the order of a million nucleotide pairs in their genetic code, and more complex (eukaryotic) organisms from algae to flowering plants and mammals contain 1 to 10 billion nucleotide pairs.  None has yet been completely decoded.
    Because of their great age and genetic complexity, species are exquisitely adapted to the ecosystems in which they live.
    The number of species on earth is being reduced by a rate 1,000 to 10,000 times higher than existed in prehuman times.  The current removal rate of tropical rain forest, about 1.8 percent of cover each year, translates to approximately 0.5 percent of the species extirpated immediately or at least doomed to much earlier extinction than would otherwise have been the case.  Most systematists with global experience believe that more than half the species of organisms on earth live in the tropical rain forests.  If there are 10 million species in these habitats, a conservative estimate, the rate of loss may exceed 50,000 a year, 137 a day, 6 an hour.  This rate, while horrendous, is actually the minimal estimate, based on the species / area relation alone.  It does not take into account extinction due to pollution, disturbance short of clear-cutting, and the introduction of exotic species.

    Other species-rich habitats, including coral reefs, river systems, lakes and Mediterranean-type heathland, are under similar assault.  When the final remnants of such habitats are destroyed in a region—the last of the ridges on a mountainside cleared, for example, or the last riffles flooded by a downstream dam—species are wiped out en masse.  The first 90 percent reduction in area of a habitat lowers the species number by one-half.  The final 10 percent eliminates the second half.

     It is a guess, subjective but very defensible, that if the current rate of habitat alteration continues unchecked, 20 percent or more of the earth's species will disappear or be consigned to early extinction during the next thirty years.  From prehistory to the present time humanity has probably already eliminated 10 or even 20 percent of the species.  The number of bird species, for example, is down by an estimated 25 percent, from 12,000 to 9,000, with a disproportionate share of the losses occurring on islands.  Most of the megafaunas—the largest mammals and birds—appear to have been destroyed in more remote parts of the world by the first wave of hunter-gatherers and agriculturists centuries ago.  The diminution of plants and invertebrates is likely to have been much less, but studies of archaeological and other subfossil deposits are too few to make even a crude estimate.  The human impact, from prehistory to the present time and projected into the next several decades, threatens to be the greatest extinction spasm since the end of the Mesozoic era 65 million years age.

     Assume, for the sake of argument, that 10 percent of the world's species that existed just before the advent of humanity are already gone and that another 20 percent are destined to vanish quickly unless drastic action is taken.  The fraction lost—and it will be a great deal no matter what action is taken—cannot be replaced by evolution in any period that has meaning for the human mind.  The five previous major spasms of the past 550 million years, including the end-Mesozoic, each required about 10 million years of natural evolution to restore.  What humanity is doing now in a single lifetime will impoverish our descendants for all time to come.  Yet critics often respond, “So what? If only half the species survive, that is still a lot of biodiversity—is it not?”

     The answer most frequently urged right now by conservationists, I among them, is that the vast material wealth offered by biodiversity is at risk.  Wild species are an untapped source of new pharmaceuticals, crops, fibers, pulp, petroleum substitutes, and agents for the restoration of soil and water.  This argument is demonstrably true—and it certainly tends to stop anticonservation libertarians in their tracks—but it contains a dangerous practical flaw when relied upon exclusively.  If species are to be judged by their potential material value, they can be priced, traded off against other sources of wealth, and—when the price is right—discarded.  Yet who can judge the ultimate value of any particular species to humanity?  Whether the species offers immediate advantage or not, no means exist to measure what benefits it will offer during future centuries of study, what scientific knowledge, or what service to the human spirit.

      At last I have come to the word so hard to express:  spirit.  With reference to the spirit we arrive at the connection between biophilia and the environmental ethic.  The great philosophical divide in moral reasoning about the remainder of life is whether or not other species have an innate right to exist.  That decision rests in turn on the most fundamental question of all:  whether moral values exist apart from humanity, in the same manner as mathematical laws, or whether they are idiosyncratic constructs that evolved in the human mind through natural selection.  Had a species other than humans attained high intelligence and culture, it would likely have fashioned different moral values.  Civilized termites, for example, would support cannibalism of the sick and injured, eschew personal reproduction, and make a sacrament of the exchange and consumption of feces.  The termite spirit, in short, would have been immensely different from the human spirit—horrifying to us in fact.  The constructs of moral reasoning, in this evolutionary view, are the learning rules, the propensities to acquire or to resist certain emotions and kinds of knowledge.  They have evolved genetically because they confer survival and reproduction on human beings.

      The first of the two alternative propositions—that species have universal and independent rights regardless of how else human beings feel about the matter—may be true.  To the extent the proposition is accepted, it will certainly steel the determination of environmentalists to preserve the remainder of life.  But the species-rights argument, for all its directness and power, remains intuitive, aprioristic, and lacking in objective evidence.  Who but humanity, it can be immediately asked, gives such rights?  Where is the enabling canon written?  And such rights, even if granted, are always subject to rank-ordering and relaxation.  A simplistic adjuration for the right of a species to live can be answered by a simplistic call for the right of people to live.  If a last section of forest needs to be cut to continue the survival of a local economy, the rights of the myriad species in the forest may be cheerfully recognized but given a low and fatal priority...”

     Lester R. Brown gives an update of the present biodiversity problem in his book, Plan B 3.0 Mobilizing to Save Civilization, 2008, pp. 101-105, by the Earth Policy Institute:

     “Disappearing Plants and Animals

     We are now in the early stage of the sixth great extinction.  Unlike previous extinction events, which were caused by natural phenomena, this one is of human origin.  For the first time in the earth's long history, one species has evolved, if that is the right word, to where it can eradicate much of life.

     As various life forms disappear, they diminish the services provided by nature, such as pollination, seed dispersal, insect control, and nutrient cycling.  This loss of species is weakening the web of life, and if it continues it could tear huge gaps in its fabric, leading to irreversible changes in the earth's ecosystem.

     Species of all kinds are threatened by habitat destruction.  One of the leading threats to the earth's biodiversity is the loss of tropical rainforests.  As we burn off the Amazon rainforest, we are in effect burning one of the great repositories of genetic information.  Our descendants may one day view the wholesale burning of this genetic library much as we view the burning of the library in Alexandria in 48 BC.

     Habitat alteration from rising temperatures, chemical pollution, or the introduction of exotic species can also decimate both plant and animal species.  As the human population grows, the number of species with which we share the planet shrinks.  Yet we cannot separate our fate from that of all life on the earth.  If the rich diversity of life that we inherited is continually impoverished, eventually we will be impoverished as well.

     The share of birds, mammals, and fish that are vulnerable or in immediate danger of extinction is now measured in double digits:  12 percent of the world's nearly 10,000 bird species; 20 percent of the world's 5,416 mammal species; and 39 percent of the fish species analyzed.

     Among mammals, the 296 known species of primates other than humans are most at risk.  The World Conservation Union-IUCN reports that 114 of these species are threatened with extinction.  Some 95 of the world's primate species live in Brazil, where habitat destruction poses a particular threat.  Hunting, too, is a threat, particularly in West and Central Africa, where the deteriorating food situation and newly constructed logging roads are combining to create a lively market for 'bushmeat.'

     The bonobos of  West Africa, great apes that are smaller than the chimpanzees of East Africa, may be our closest living relative both genetically and in social behavior.  But this connection is not saving them from the bushmeat trade of the destruction of their habitat by loggers.  Concentrated in the dense forest of the Democratic Republic of the Congo, a failing state with a  prolonged civil conflict, their numbers fell from and estimated 100,000 in 1980 to as few as 10,000 today.  In one human generation, 90 percent of the bonobos have disappeared.

     Birds, because of their high visibility, are a useful indicator of the diversity of life.  Of the 9,817 known bird species, roughly 70 percent are declining in number.  Of these, and estimated 1,217 species are in imminent danger of extinction.  Habitat loss and degradation affect 91 percent of all threatened bird species.  For example, 61 bird species have become locally extinct with the extensive loss of lowland rainforest in Singapore.  Some once-abundant species may have already dwindled to the point of no return.  The great bustard, once widespread in Pakistan and surrounding countries, is being hunted to extinction.  Ten of the world's 17 species of penguins are threatened or endangered, potential victims of global warming.  Stanford University biologist Cagan Sekercioglu, who led a study on the status of the world's birds said, 'We are changing the world so much that even birds cannot adapt.'

     Particularly disturbing is the recent precipitous decline in the populations of Britain's most popular songbirds.  Within the last 30 years the populations of well-known species such as the willow warbler, the song thrush, and the spotted flycatcher have fallen 50-80 percent; no one seems to know why, although there is speculation that habitat destruction and pesticides may be playing a role.  Without knowing the source of the decline, it is difficult to take actions that will arrest the plunge in numbers.

     Another decline, which began in late 2006 to March 2007 by the Apiary Inspectors of America, found that the bees in nearly one quarter of U.S. bee colonies had simply disappeared as a result of what scientists are calling 'colony collapse disorder.'  Large numbers of colonies have suffered the same fate in Europe, Brazil, and Guatemala.

     Scientists are baffled by what the French have labeled 'mad bee disease.'  Bees leaving their hives on pollination forays apparently become disoriented and never return.  The principal suspect at this writing is the Israeli acute paralysis virus, which may have originated in Australia.  If scientists cannot quickly diagnose this bee malady and devise preventive measures, the world could face an unprecedented disruption of fruit and vegetable production.

     The threat to fish may be the greatest of all.  The principal causes are overfishing, water pollution, and the excessive extraction of water from rivers and other freshwater ecosystems.  An estimated 65 percent of the fish species evaluated by IUCN that once inhabited the lakes and streams of North America are either extinct or in jeopardy.  In Europe, some 109 species of freshwater fish out of the 265 that were evaluated are threatened, endangered, or of special concern.  One third of the 97 fish species in South Africa need special protection to avoid extinction.

     The leatherback turtle, one of the most ancient animals, which can reach a weight of 360 kilograms (800 pounds), also is fast disappearing.  Its numbers dropped from 115,000 in 1982 to 34,500 in 1996.  At the Playa Grande and Playa Langosta nesting colonies on Costa Rica's west coast, the number of nesting females dropped from 1,504 in 1989 to 62 in 2003, then rose slightly to 174 in 2004.  Writing in Nature, James Spotila and colleagues warn that 'if these turtles are to be saved, immediate action is needed to minimize mortality through fishing and to maximize hatchling production.'

     One of the fastest-growing threats to the diversity of plant and animal life today is the extraordinary agricultural expansion now under way in Brazil as land is cleared to graze cattle, plant soybeans, and, more recently, produce sugarcane for ethanol.  Farmers and ranchers are opening up vast areas in the Amazon basin and in the cerrado, a Europe-sized savanna-like region south of the Amazon basin.  Although there are mechanisms in place to protect the rich biological diversity of the Amazon, such as the requirement that landowners clear no more than one fifth of their land, the government  lacks enforcement capacity.

     Like the Amazon, the cerrado, is biologically rich, home to many large mammals, including the maned wolf, giant armadillo, giant anteater, deer, and several large cats—jaguar, puma, ocelot, and jaguarundi.  The cerrado contains 607 species of birds, including the rhea, a cousin of the ostrich, which grows up to five feet tall.  An estimated 10,000 plant species—at least 4,400 of which are endemic, not found anywhere else.

     Another worldwide threat to species, and one that is commonly underestimated, is the introduction of non-native species, which can alter local habitats and communities, driving native species to extinction.  For example, non-native species may be responsible for 29 percent of the threatened bird species on the IUCN Red List.  For plants, alien species are implicated in 5 percent of all the listings.

     Efforts to save wildlife traditionally have centered on the creation of parks or wildlife reserves.  Unfortunately, this approach may now be less effective, for if we cannot stabilize climate, there is not an ecosystem on earth that we can save.  Everything will change.

     In the new world we are entering, protecting the diversity of life on earth is no longer simply a matter of setting aside tracts of land, fencing them off, and calling them parks and preserves.  Success in this effort depends also on stabilizing both climate and population.

     On the plus side, we now have more information on the state of the earth and the life on it than ever before.  While knowledge is not a substitute for action, it is a prerequisite for saving the earth's natural systems—and the civilization that they support.”

Thomas Lovejoy makes an urgent plea for action to stop our assault on the biological diversity on Earth in the January 2013 issue of Scientific American magazine:

     In his article “A Tsunami of Extinction”, Thomas Lovejoy (who coined the term biological diversity and played a major role in the development of the science of conservation biology) tells us that by the next century lions, tigers and many other species will be gone or found only in zoos.  He explains the roles of invasive species, wildlife diseases, declining natural habitat, distortion of the global nitrogen cycle, and climate change are causing a biodiversity crisis on Earth.  Read the entire article by going to January 2013 issue in ScientificAmerican.com.
 
 Lovejoy's awareness-raising writing speaks with an authoritative sense of urgency:

     “...Today's Red List of Threatened Species, from the International Union for Conservation of Nature, estimates that 13 percent of bird, 25 percent of mammal and 41 percent of amphibian species face possible extinction.
     Many species are on a path to become what scientists term the 'living dead' – populations so small that extinction is inevitable.  A century from now most of the big carnivores – including lions, tigers and cheetahs – will probably exist only in zoos or wildlife areas so small as to be quasi zoos.  The same fate may wait all rhinoceros and elephant species and our closest wild relatives:  the two gorilla species, orangutans and chimpanzees... We need to come to our senses.  A critical first step would be to renew efforts to meet the goals of the convention on Biological Diversity, which calls for formal protection to be granted to 17 percent of terrestrial freshwater ecosystems and to 10 percent of oceans by 2020... All these actions require political will, a recognition that the planet should be managed as the biological and physical system that it is, and an awareness that the diversity of life – of which we are a part – is critical for the future of humanity.” 

For a comprehensive review of information concerning the biodiversity crisis of the Sixth Major Mass Extinction of life on Earth, visit the website: www.well.com/user/davidu/extinction.html.
 

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