Twenty years ago a group of nine leading American biologists warned that destruction of wildlife habitats and their genetic and species diversity was a threat to civilization "second only to thermonuclear war". Since then their concerns have largely gone unheeded but their dark prophesies are beingfulfilled. Life on earth may, at best, take millions of years to recover. We have had the Rio convention, yet the forest is burning 34% faster and the seas are being overfished. In the next 25 years, if we don't take decisive action the greatest species extinction for 200 million years will in all probability occur. An irreversible loss which will severely compromise both the future prospects of humanity and the future evolutionary potential of the biosphere, for which we will be condemmned by our descendents for untold centuries to come. There is still time to turn the tide of ignorance and inertia for the future of life.
The Sixth Great Extinction: The current extinction is different from previous ones because it is we who are causing it despite our supposed intelligence. Previous extinctions are believed to have been caused by large astronomical impacts. A putative crater has been found in Yucatan for the Cretacious-Tertiary event 65 million years ago, and possibly off Australia for the more serious Permian 220 million year event where up to 96% of hard-shelled marine species died. There are also theories of longer-term massive volcanic formations. Notably the Deccan traps are opposite Yucatan so could be part of the same phenomenon. The Permian extinction was also associated with a massive shrinking of the oceans and then a refilling, severely disrupting the shoreline ecosystems. Another suggestion about the Permian extinction is that a nearby supernova disrupted the magnetosphere and ozone layer irradiating life. (New Scientist Apr 98). Chaotic population fluctuations have also been suggested to play a part in extinctions and even the earth passing through a region of dark matter has been suggested as an alternative source of volcanic disruption. Further back is a putative short-phase extinction in the Cambrian.
Periodic extinctions (Gould 1993).
Finally there are the suggestions that an infrequent but periodic astronomical disturbance such as a dark twin may cause 26 million year cycles of devastation by disturbing the outer members of the cometary belt, that the solar system may orbit out of the galactic plane exposing it to greater gamma radiation from the galactic centre, or even that intermittent dark matter may cause stress to the earth.
Although extinctions can provide opportunities for new radiative diversifications as evidenced by the rise of the mammals from the dinosaur extinction, it is extremely unlikely that a human-induced mass extinction is going to benefit the human species. It is more likely to result in our own extinction over time.
Ecosystems around the world recovered from the mass extinction which wiped out the dinosaurs in diverse patterns, some rapid and others prolonged, according to fossil records of such marine animals as giant clams New Scientist 7 Mar 98
Evolution is a process of change and species extinction is as natural as the emergence of new ones. During the history of earth, many more species have existed than remain on earth today. However what is unique about the current situation is that a single species, man is causing a mass extinction whose probable significance is at least the fourth biggest in history. The extinction rate is thus phenomenally increased over the 'natural' condition. This extinction rate has been gathering pace over the last ten thousand years to a dizzy peak this century and next. Humankind has altered its environment for millennia, causing some domesticated and weedy species to prosper but many others to suffer, especially good sources of food such as the large land animals. In some ways this has been of great benefit to humanity, through the global spread of crops and domesticated animals around the world. But it has also led to catastrophic extinctions. Many large species of mammals and birds died out about 10,000 years ago - and some scientists believe that this was caused, in significant measure by the activities of early man. "The arrival of the Polynesians on the Hawaiian Islands 1,500 years ago is thought to have consigned as many as 40 bird species to oblivion, nearly three times as many as have perished over the last four centuries" (Lean 136).
Chart of biodiversity attrition in four continental or major island regions going back 100, 1000, 10000, and 100,000 years shows major impacts of humanity by pre-literate societies (Wilson 1992).
This century species have been destroyed by three principal routes:
Human activity and its impacts such as pollution are now changing the natural world at a rate unprecedented in evolutionary history, and mass extinctions are a virtual certainty. By some estimates, a million species will have died out during the last century, but even this is possibly a vast under-estimate because the number of uncharacterized species in many small species, from insects to bacteria, may exceed the known ones by an order of magnitude. "It is hard to be accurate about extinctions, since most are unrecorded; the vast majority of the world's species have neither been named nor classified" (Lean 136). These difficulties are sometimes exploited by opponents of biodiversity conservation, but the arguments do not hold. The sheer scale of the devastation caused as whole forests are systematically burned and cleared of their natural diversity and large habitats fragmented into small islands is qualitatively devastation, which will have a very significant impact on diversity. The more species there are on Earth the worse the scale of the loss becomes.
Although much concern and attention is focused on the continental land-masses, and particularly on tropical rainforests most extinctions recorded have been on islands because their endemic habitats and small populations easily lead to extinction of an entire species. "About 108 bird species are known to have become extinct in the last 400 years; 97 of them were Island-dwellers. Similarly, islands account for about 75 per cent of all mammals driven to extinction. More than 90 per cent of the endemic plants on St Helena, Ascension Island and Lord Howe Island face extinction, along with more than 80 per cent of those in the entire Seychelles island group" (Lean 136). But island species are particularly vulnerable if they are endemic. They have nowhere else to go when they come under attack. And they may have few defences against predators, like cats or rats, that are introduced onto the islands, because they have evolved in environments where they have no natural enemies. One such species was the proverbial dodo which, during its long evolution on the island of Mauritius, lost both its power of flight and its sense of fear when neither was needed. It is precisely the division of continental wilderness habitats into many small islands which could also lead to biodiversity catastrophe on the continents.
A Case: Endangered New Zealand Birds
A particularly poignant case is New Zealand, which until the coming of humanity had one of the most isolated ecosystems on Earth containing no mammals. The forests are all adapted to seed spread through bird species, many of which are now under threat. First the large flightless birds were destroyed by the Maori with the loss of the world's largest eagle. The introduced species, plant and animal alike have run riot. Virtually all of the flightless birds are extinct or facing extinction.
Over 30% of New Zealand native birds are endangered, compared with 12% worldwide, partly as a result of its unique and isolated ecosystem with many flightless birds. The Kiwi is the symbol of New Zealand sovereignty, yet the national symbol has become an endangered animal. Such flightless birds are very effective at foraging in the forest floor and despite having an egg a sizeable proportion of the mother's body weight, can reproduce rapidly if the young chicks are not killed. However possums and domestic dogs are threatening its future survival. It may literally become the living logo of the Bank of New Zealand, itself ironically foreign-owned, because its viability in the wild is tenuous.
Estimates of several extinct species retrospective survival projections show that many existing native birds are also likely to disappear: (Percentages all odds against survival)
Extinct: Little Bush Moa 94%, Chatham Islands Bellbird 79%, Adzebill 99%, Chatham Islands Snipe 87%, NZ Quail 22%, Large Bush Moa 97%, Giant Moa 97% , Haast's Eagle 96%, Huia 99%, Chatham Islands Huia 61%, NZ Crow 92%
Endangered: North Island Brown Kiwi 61%, Great Spotted Kiwi 61%, Little Spotted Kiwi 99%, Kokako 97%, NZ Falcon 0.6%, Weka 94%, Kaka 15%, Kea 20%, Black Robin 49%, Takahe 58%, Kokako [population 50] 100%.
Not Threatened: Rifleman 3%, Bellbird 4%, Morepork 44%, NZ Robin 1.2%, Tui 11%.
The loss of virtually all of the large bodied bird species could cause major crisis for New Zealand forest ecosystems, which are strongly adapted to depend on the bird life for both fertilization and dispersal of large seeds through being eaten. The Kereru (Kukupa to Northern Maori) or New Zealand wood pigeon is a keystone species for seed dispersal which is becoming threatened by introduced species such as wild stoats and rats in addition to traditional Maori hunting. The reduction of this species to offshore islends could irreversibly truncate the future diversity of NZ native forests.
The Kiwi is New Zealand (Aotearoa's) national symbol. It currently numbers in the tens of thousands, but this fundamental aspect of our identity is due to disappear from the mainland sometime mid next century. Kiwi are ratites like the Ostrich, which is farmed, but moves are only just beginning to learn to breed it in captivity successfully. The female contributes a third of her body weight to the egg - the largest egg to body weight of any bird. Nevertheless kiwi are quite fertile under normal conditions. However the introduction of mustelid stoats and ferrets has seen reproduction grind to a standstill, because all offspring are killed before they can reach the robustness of adolescence. Opossums also eat their eggs and a single dog killed 500 in a national park. The male is left to tend the brood and he forages at night leaving the burrow defenceless to nocturnal predators.
The Value of Biodiversity: The value of biodiversity is that it provides us with a more robust biosphere more likely to sustain humanity long into the evolutionary future. Our long-term survival prospects are intimately connected to the richness of biodiversity. The more we reduce it to a fragile skeleton the greater the danger we will ourselves expire as a species through even a mild disruption to the earthly environment. The better integrated our food plants remain with their natural sources of biodiversity the more likely we will continue to have them to depend on in future evolutionary time scales. The more diverse the more adaptable to unforeseen stress.
Causes of Diversity
Causes of diversity are as diverse as diversity itself. Some explanations for the diversity hot spots found in some areas such as the upper Amazon are mentioned here. A first factor is that the forest has retreated into many separate sanctuaries during drier spells in ice ages and then been repeatedly reintegrated again. Another factor for diversity is the rise of forest to climax in an environment of damage through storm and fire creating a fractal dynamic of destruction and regeneration over evolutionary time-scales. Another factor is the idea that diversity is an evolutionary response to attack by pathogens. Diversity minimizes crises caused when a pathogen mounts an attack on a dominant species (New Scientist 23 March 1996 38).
The Conflagration of Genetic Diversity
The next few decades will witness a wildlife holocaust, a great extinction numbered among the five most serious threats to life in earth during its entire history. By the turn of the millennium, over a million kinds of animals, plants and fungi are expected to be driven to extinction; by the year 2050, half of all the species alive today could be lost forever. The disaster threatens to surpass the mass extinction of 65 million years ago when the dinosaurs disappeared. The causes are diverse, but they all come down to human impact without foresight. Overhunting and overfishing, pollution and the trade in wildlife all play a part. But by far the greatest cause of the extinctions is the destruction of wild habitats for farming, fuel, industry and a host of other uses. The world's tropical rainforests, which contain at least half the world's species, are failing fast: little more than half of their original expanse still remains, and an area as big as Romania is cleared each year. The temperate forests are likewise under siege in Siberia. Half the world's wetlands - other abundant habitats - have been drained or developed and species-rich coral reefs are being destroyed throughout the earth's warmer seas. Species are now becoming extinct at 25,000 times the natural rate (Lean 127). Currently there is a species being lost about every 12 minutes and the rate is steadily increasing as remaining areas of high diversity become fractured. The loss of one plant can cause the loss of as many as 30 kinds of animals and insects which depend upon it, so the whole process has catastrophic potentiality.
Even the loss of a single species can be a tragedy, because each form of life is a storehouse of irreplaceable substances. Every civilization has been rooted in the wealth of nature the local environment has provided. The collection of seeds and domestication of wild animals made the first agriculture and shepherding of flocks possible. Selective breeding has subsequently made our domesticated and food species more productive; and abundant natural resources enabled the agricultural and urban social revolutions to take off, later leading to the industrial revolution whose consequences so effect biodiversity today. Despite these changes, genetic resources, taken from the wild, still sustain modern societies, providing medicines, food and raw materials for industry. They also form the foundation resource for genetic technologies of the future. Without biodiversity, biotechnology is a destitute science.
Biodiversity Losses Cost Billions
The economic costs of biodiversity loss are becoming apparent in well-studied ecologies such as that if the U.S. "To lose any more of the remaining 3214 rare and endangered plant species in the US could mean throwing away a fortune. In the first study to put a price on this vanishing vegetation, Brien Meilleur of the Missouri Botanical Garden in St Louis and Oliver Phillips of the University of Leeds estimate that rare plants in the US could be worth billions of dollars a year: 'The public tends to think we are losing oddities that might be interesting but don't have much impact on society. These figures contradict that.' The survey revealed that 80 per cent of America's threatened plants belong to a genus that includes at least one, and often many, useful species (Economic Botany, vol 52, p 57). 'Biotechnology makes it easier to move genes around, so wild relatives could make more of a contribution to the cultivated ones in future,' says Phillips" (New Scientist May 98). The value of the endangered species is likely to multiply with biotechnology rather than diminish.
Extinction Threat for World's Tree Species NZ Herald 7 Sep 98
LONDON One in 10 of the world's tree species face extinction through felling, forest fires and poor forest management, conservationists said last week. "With 77 species already extinct, this report has now confirmed our worst nightmare," said Dr Steve Howard of the World Wide Fund for Nature. The world list of threatened trees details over 8753 of the world's 80,000 to 100,000 tree species as being in danger of extinction. The list is the product of a three-year project by the. World Conservation Monitoring Centre, which is partly funded by the wildlife fund, and the Species Survival Commission of the World Conservation Union. Dr Howard called on governments meeting in Geneva last-week for an intergovernmental fonim on forests to act quickly to save the trees. "The governments -... must now realise the sense of urgency to increase forest protection, eliminate illegal logging and improve forest management,". Dr Howard said. The list includes several species withjust one tree left, such as China's single remaining Carpinus putoensis which survives, fenced off, at the edge of a sparse forest, the victim of deforestation. Conservationists warned most living species were dependent for their survival on trees. "If we can't save these elephants of the plant world, then the prognosis for all other species wldch depend on trees is frightening," said Dr Wendy Strahm of the conservation union. NZPA
A Case: Non-resistant pathogenic Bacteria
A handful of soil is believed from DNA analysis to contain upwards of 10,000 different species of cryptic bacteria. With this manifold diversity it is hard to conceive of running short of bacterial diversity, especially of dreaded pathogenic species, but that is precisely the situation at risk. The world is facing a crisis of antibiotic resistance. Everywhere we turn,we are using antibiotics. Many of these uses are unnecessary such as in growth promoters in livestock production and the prescription of antibiotics prophylactically for viral infections. In applying antibiotics so freely we are systematically causing antibiotic resistance in non-pathogenic bacteria which is subsequently transferred to pathogenic species. Only by retaining the non-resistant strains of each of these species in their full vigor can we slowly breed out again the resistant strains, because the metabolic load of their resistance genes slightly slows their growth rate. This is a paradox - the need to love our enemies - even tuberculosis and plague because their esisstant sisters could prove even more deadly.
Over a quarter of current medicines are sourced in plant products. Many others such as antibiotics have origins in bacteria and other organisms. "Worldwide, medicines from wild products are worth some $40 billion a year. This can also be a problem because rare species can be hunted to extinction for their supposed medicinal value. Fox gloves have saved millions from the effects of heart disease, through digitalis. Snakeroot plant from Indian forests relieves hypertension. Bee venom treat arthritis. Codeine and morphine come from poppies. Amazonian species provide an extraordinary wealth of medicinal compounds including quinine for malaria, curare for paralysing muscles, and a wide variety of medicines which number in the hundreds even for a single tribal healer. The rosy Madagascan periwinkle has improved the survival prospects from less than 20% to over 80% in children with leukaemia. So far over 1,400 tropical forest plants and 500 marine organisms yield chemicals with the potential to fight cancer; but many may be driven to extinction before their promise can be assessed or tapped. Currently researchers estimate only 10% of all species may have been documented and many of these will be lost before we ever find out what potential treasures they contain" (Lean et. al. 127).
Wasting the Sheaf of Demeter: The Dwindling Diversity of Food
The health of the world's food resources and harvest productivity is even more dependent on genetic resources. We are utterly dependent on our domesticated food plants and animals for our own survival. Many of these are dwindling in diversity as diverse local types of produce give way to large industrial productions for world markets. The number of different species being used is dropping rapidly and even more worrying the genetic diversity of even our major staples is being reduced rapidly by major production of low-diversity and even frankly monoclonal genetically-engineered varieties. "Just three species - wheat, rice and maize - provide half the world's food; another four - potato, barley, sweet potato and cassava - bring the total to three quarters. Such overwhelming dependence on a few crops is dangerous; disease can spread rapidly through monocultures - as it did through the Irish potato harvest in the 1840s, causing a fifth of the country's people to die" (Lean et. al. 127).
Crops need to be given new protection every few years, because pests and disease develop ways around their existing defences, requiring one to interbreed them with other strains, often wild ones to introduce new traits. It is believed that the evolutionary race between parasite and host is a principal reason for sexuality in higher organisms. "In the 1960s an epidemic of the wheat disease, stripe rust, struck the US; the state of Montana repeatedly lost a third of its harvest. Genes from a wild wheat from Turkey saved the situation, providing resistance to this and 50 other diseases. In 1970 an even more virulent plague spread by up to 150 kilometers a day across the American corn belt. lt devastated a sixth of the maize crop, wiping out half the harvest of some Southern states, at a cost of some $2 billion" (Lean 127). Nevertheless modern industrial agricultural and forestry processes are depending ever more recklessly on monoclonal genetically-engineered varieties. Indonesia plans to plant 250,000 hectares of forest in genetically-engineered monoclonal teak in a single operation. The burning question is where the next generation of such trees will come from once they succumb to parasite adaption if the wild areas containing the genetic diversity from which these varieties come are converted to plantation use. Such short-term thinking could become an evolutionary terminal condition for humankind.
"Maize has been particularly vulnerable to such disasters, as inbreeding has given it an almost uniform genetic pattern - and new genes from wild varieties have been urgently needed. Two ancestors of the plant were found in Mexico in the late 1970s; they can confer resistance to seven of the domestic crop's major diseases, and can turn it into a perennial crop, allowing it to spring up every year like grass, without resowing. These maizes have been called the botanical find of the century; ominously, just a few stalks of them were discovered in a tiny area now threatened with destruction" (Lean et. al. 127).
The diversity of many of our essential food plants is thus at best marginally conserved.
The growing of commercial hybrid stocks of low diversity over vast productive areas of the
earth's surface has a catastrophic effect on the diversity of the very species on which we depend.. The original ecosystemic variety of locally-adapted types is lost as entire populations convert to only a few types. Disease resistance is often only later to be discovered to be missing in all but one or two of the cultivated varieties. Wild varieties in their original habitat are frequently under threat. Plant patenting drives diversity down further , placing legal constraints on free propagation, reducing the entire world market to a few patented varieties, which often have low biodiversity because they are developed from a few highly selected individuals, or even a single parent.
Genetic engineering has even more worrying implications. The first is that new traits are introduced or old ones lost which permanently alter the viability of the species in its own right. Tomatoes which cannot rot cannot naturally nurture their seeds and plants producing alien insecticides may damage the very insects which pollinate them. Some such species contain in addition antibiotic resistance genes which could spread to viruses causing further unnecessary havoc. Recently a terminator gene has been developed which will render engineered plants infertile on the second seeding making the entire species terminal. Such developments could become the death knell of the very species upon which we depend.
The story of the essential importance of rare diversity has been repeated endlessly in recent history. "Most of Brazil's coffee traces its ancestry back to a single tree, imported from East Africa via the Caribbean. In 1970 disease struck its crop and spread through Latin America, threatening several national economies with disaster. A wild coffee from Ethiopia's fast-disappearing forests was used to prevent a recurrence. Genes from a Javan species of sugar cane have saved plantations in the Southern US from disaster; and in the early 1970s only one of 6,273 different species of rice screened by the International Rice Research Institute could be found to protect varieties against a disease called grassy stunt then sweeping Asia" (Lean 127).
Interbreeding with wild varieties can increase yields and extend the area available for productive agriculture. "Nearly 10 million square kilometers of land around the world, for example, is too saline for agriculture, much of it ruined by faulty irrigation schemes" (Lean 128). Some strains of wild wheat, rice, barley, millet and sorghum grow well on salty land; they could be used to create new crops for the ruined fields. This could possibly increase production by up to a half again.
Most people do not realize how precarious the genetic resource of our food plants is. "Four varieties of wheat produce 75 percent of the crop grown on the Canadian prairies. More than half of the prairie is sown with a single variety. Four cultivars of potatoes account for 72 percent of production in the United States. All of the coffee trees in Brazil have been derived from the seedlings of a single plant cultivated in the Amsterdam Botanic Garden in 1709. The entire United States soy-bean stock came from six plants from one place in Asia. The consequences of relying on such a small range of genetic material for our crops can be disastrous. Sri Lanka (formerly Ceylon), for example, was a major coffee producer until the crop was decimated by disease in 1869. Due to an insect pest, phylloxera, virtually all of Europe's grape vines were destroyed between 1870 and 1900. Since rootstocks from wild grapes were resistant, they were grafted to European stems and the vineyards recovered." (Ayensu, Heywood, Lucas, & Defilipps 208)
The cultivation of genetically uniform, high-yielding, and advanced cultivars carries with it very high risks of total crop failure through disease or pests. It is for this reason that there is a drive worldwide to conserve genetic resources of crop plants and their wild relatives so that there are genetic reservoirs available to the plant breeders to provide the raw material for future adaptations and for tomorrow's new cultivars.
Today, within biodiversity all kinds of unexplored genetic permutations exist few of which have been explored by gene technologists. Because of the protein-folding problem and the complexity of enzymes genetic technology depends on existing biodiversity for its repertoire of possibilities. Some of these are expressed in overt traits, but others may be hidden in the genetic code. They are discovered individually as we classify new species, or hybridize new plants. Botanists and breeders need to take account of a bewildering array, in highly complex species, of off-beat traits to take account of the genetic diversity presented by a single species. Due to the extraordinary variability found within plant species, there are large numbers of uninvestigated alleles - genetic traits - in many of them. It is difficult to overestimate the importance of conserving such genetic potential and diversity. Wild relatives of domesticated plants can often provide genetic 'renewal' when current varieties become susceptible to disease or are otherwise threatened.
These are also used in breeding for improved yield and nutrient content, as well as in the production of new strains of crops. Chromosome and gene variation within plants is an enchanted loom from which new marvels can appear at any time. The richer diversity remains, the richer the genetic possibilities in the future through such evolution.
"Genetic material introduced from wild species has already helped to double the yield of sugar cane. Yields of wheat, rice, and other grain cereals have risen dramatically around the world through newly created strains - the so-called Green Revolution A major problem with today's methods of large-scale farming is that the highly-bred, uniform strains of crop plants are grown over such vast areas that one epidemic could wipe out the whole season's harvest. The average lifetime of wheat cultivars in Europe and North America is only five to fifteen years because pests and pathogens themselves evolve new races that combat the genetic resistance of plants." (Ayensu, Heywood, Lucas, & Defilipps 208).
There must always be an effort underway to introduce new vigor into crops. Often wild relatives are the only ones retaining disease resistance genes. Therefore, it becomes imperative to preserve as many of these as possible, seeking them out in the habitats where they have been discarded to be replaced by new selected commercial strains that are more vulnerable to disease in the long run.
Goodbye to Oceanic Diversity
"The evidence is everywhere. Populations of fish and shellfish, of corals and mollusks, of lowly ocean worms, are plummeting. Toxic tides, coastal development and pollutant runoff are increasing in frequency and dimension as the human population expands. The oceans - near shore and in the abyssal deep - may be reaching a state of ecological crisis, but, for the public, what is out of sight is out of mind. 'The oceans are in a lot more trouble than is commonly appreciated,' rues Jane Lubchenco of Oregon State University. 'There is great urgency.' ... Identifying threats to the oceans was straightforward. Although the usual suspects were in the lineup - including oil spills, the destruction of estuaries, toxic dumping and the introduction of nonindigenous species that outcompete the locals - conference attendees deemed fishing the greatest danger to marine biodiversity" (Scientific American Aug 94 10).
"The fundamental folly underlying the current decline has been a widespread failure to recognize that fish are wildlife - the only wildlife still hunted on a large scale. Because wild fish regenerate at rates determined by nature, attempts to increase their supply to the marketplace must eventually run into limits. That threshold seems to have been passed in all parts of the Atlantic, Mediterranean and Pacific: these regions each show dwindling catches. Worldwide, the extraction of wild fish peaked at 82 million metric tons in 1989. Since then, the long-term growth trend has been replaced by stagnation or decline. In some areas where the catches peaked as long ago as the early 1970s, current landings have decreased by more than 50 percent. Even more disturbingly, some of the world's greatest fishing grounds, including the Grand Banks and Georges Bank of eastern North America, are now essentially closed following their collapse - the formerly dominant fauna have been reduced to a tiny fraction of their previous abundance and are considered commercially extinct. Recognizing that a basic shift has occurred, the members of the United Nations's Food and Agriculture Organization (a body that encouraged the expansion of large-scale industrial fishing only a decade ago) recently concluded that the operation of the world's fisheries cannot be sustained. They now acknowledge that substantial damage has already been done to the marine environment and to the many economies that depend on this natural resource. Such sobering assessments are echoed in the U.S. by the National Academy of Sciences. It reported this past April that human actions have caused drastic reductions in many of the preferred species of edible fish and that changes induced in composition and abundance of marine animals and plants are extensive enough to endanger the functioning of marine ecosystems" (Scientific American Nov 95).
The Frogs are Croaking: There is a world-wide decline in frog populations to the point of international crisis concern. Frogs are susceptible to environmental toxins and pollution because of their permeable skins.
Preserving Diversity in the Wild
Conservation in the wild is difficult or impossible for domesticated species. Genetic resources often have to be stored in seed banks, germ plasm collections, or by tissue culture. The loss of genetic variety of the wild relatives of crop plants - genetic erosion - may be caused by:
Left: Global demand for the the pitcher plant Cephalotus follicularis has decimated populations in its native Australian swamps. It is now listed in CITES appendix II (Ayensu 124).
The horticultural industry sometimes acts as a valuable force in conservation by the propagation and distribution of rare species, but this trade, as in the case of agriculture and forestry, has to replenish its stocks from the wild and this sometimes strips rare species from the wild, particularly through smuggling, especially of bulbs, rock plants, cacti and succulents, wild birds, lizards and even great apes. They often focus their attention on the rarest species - for these fetch the highest prices. This can lead to exploitation of many wild populations by rogue smugglers and traders. Often the plants or captive animals are badly packed and do not survive shipment. Collectors of rare species often drive the market through their insatiable passion for the rare and unusual. Even botanists can be serious offenders when collecting specimens of rare species for preservation in their private collections of dried plants.
Specialist horticulturalists, both professional and amateur, who concentrate on particular groups such as orchids, ferns, succulents, and alpines can have a very important role to play. They may successfully cultivate a very rare species and make it common; thus helping to remove pressure from the wild population, while fulfilling the needs of the trade and helping with introduction of rare species back into the wild. Techniques are being worked out to propagate and cultivate plants and satisfy the needs of collectors.
Cycads - exemplified by the sago palm have persisted with no real evolutionary change for more than 50 million years - are now collected too heavily. They are thus becoming collectively rare as an entire group. In the Transvaal the cycad loss from the wild was so rapid that protective laws were enacted in 1971. To control the trade, all owners were required to have their plants licensed. Eight thousand permits were issued to owners of sixty-four thousand plants during the first eighteen months of the program (Cycads of South Africa, Cynthia Giddy).
Harvesting of wild flowers can also be a threat to native species in areas rich in endemic species. Since many of them set few seed, commercial collecting can lead to serious dangers of extinction. Conservation plans should also allow for setting up a local horticultural trade because this can complement preservation in the wild as long as it is designed to give a steady production and income at the local level, rather than a quick selling off of the wild stocks.
Many other deliberate changes have an impact. Selective removal of plants poisonous to cattle can drive species to extinction but the same toxins may in other contexts supply irreplaceable biochemicals. This has been notable in a variety of cases from curare in arrow poisons to the painkillers in cone snail venom. As biodiversity becomes diminished our future options are slipping through our fingers diminishing by degrees, like tumbling sand.
Recent advances in cancer chemotherapy, based on alkaloids, have revived interest in mass screening of plant tissues for medical activity. Several plant-sourced drugs from Madagascar Periwinkle (vincristine) to Pacific Yew (taxol) play pivotal roles in cancer prevention. Most such superdrugs probably are to be found in the equatorial regions because this is both where biodiversity is richest and where adaptive responses are most extreme.
In the tropics, new technologies, often imposed on a massive scale, without due regard for the impacts caused, can damage the entire genetic base of the ecosystem. .There is a tendency to divide wilderness regions into ever smaller islands destroying ecosystemic connectivity and all long range habitats, selectively wiping out certain types of organism. Plantations are most frequently in exotic species and agribusiness methods low in diversity and destructive of ecosystems are also imported. Through such ingress, many native animals, insects, and other plants are lost - with damage to the whole web of vital ecological relationships. Drainage of wetlands for farms often means the loss of native species.
Genetic erosion threatens the genetic diversity of a wide spectrum of species, even relatively common ones, because the original pool of genetic variability that existed in the species has been reduced through the destruction or loss of large parts of their distribution area and or population. . "As forests are felled, marshes are drained, sea coasts are turned into holiday resorts, mountain pastures are trampled and grazed, heathlands are changed into grassland, old rich meadows are ploughed up and planted to crops or re-seeded with standard grass mixtures, cattle and sheep grazing is intensified, cities expand, industry spreads and roads are widened, so the genetic diversity of all plants in every part of the world is diminished" (Hawkes in Ayensu, et. al. 208).
The widespread damage that the biosphere is sustaining, through physical and chemical damage to the biota, land and waters, particularly in terms of genetic erosion, is far more serious than most people realize, although the cumulative effects leading to an environmental tragedy may take five decades to unfold (Ayensu, et. al. 208).
The disappearing corn cockle In developed and developing nations, technological change can bring unexpected genetic erosion. An example from Britain shows dramatically one small effect. Britain is broken up into one hundred and twelve botanical sub-divisions or vice-counties. The Corn Cockle (Agrostemma githago) was once widespread in grain fields occurring in a hundred and four of the vice-counties, many local floras recording it as "common." The plant began its disappearance with the improved seed-cleaning techniques introduced in the 1920s. With the advent of herbicides in the 1960s, its decline became even more rapid. Extremely rare today, it is found in only two counties in England and one in Scotland. Its only hope is the gardener, and the garden - the court of last resort for saving this beautiful flower, one of considerable horticultural merit. If the Corn Cockle and its many companion cornfield weeds can be maintained by horticulture or appropriate "subsidized farming methods," so much the better. (Ayensu, Heywood, Lucas, & Defilipps 208)
Conserving Resources for a Changing Future
New foods and future medicines are still to be found in the wilderness. "Some 3,000 plant species have been used as food at some time, and another 75,000 - more than a quarter of all known species - are edible. A grass called Job's Tears is an extremely nutritious, but undeveloped cereal. A Paraguayan plant produces calorie-free substances 300 times sweeter than sugar, and a coffee entirely free from caffeine has been discovered on the Comoros Islands near Madagascar. Some species could provide much needed food in arid areas. One Australian grass can yield good crops even if it is only watered once. The Marama Bean of the Kalahari desert produces both beans and nutritious roots, while the Somalian Yeheb nut was rescued from extinction to be commercially grown in East Africa" (Lean et. al. 132).
Such diversity of genetic resources will be needed more and more as human numbers grow and marginal land is increasingly utilized - and global warming alters the world's climate and rainfall patterns. New crops, and new strains of existing crops, will be essential if the new circumstances are to be addressed. But everywhere, wild plants animals and fungi which could provide them are being allowed to die out. Industry, likewise, relies on wild species. "Wood and rubber play an enormous part in daily life; rubber was originally used by South American Indians to make toys for their children. Gums, like gum arabic or gum tragacanth are used in inks and cosmetics, sweets and pharmaceuticals, liqueurs and dyes. Frankincense and myrrh are still used in incense and perfumes, as are the flowers of the ylang-ylang tree. Natural oils are already replacing mineral oils as feedstock for the chemical industry, and are beginning to take over from petrol in cars. Palm oil is used in a hundred products from lipstick to tinplate, ice cream to jet engines; but hardly any of the world's 28,000 species of palm have been investigated by scientists" (Lean et. al. 132).
"Only a fraction of 1 per cent of the world's species has been properly studied for its potential value to humanity in medicines, food or industry. So far scientists have managed to name about 1.4 million of them, but most remain anonymous and unknown. There may be a total of 5 million species on the planet or even, according to the latest estimates, more than 30 million" (Lean et. al. 132). A whole spectrum of undiscovered bioactive molecules spanning cures for intractable disease, through new industrial materials to foods are being squandered through lack of insight for their future value in the rush for a quick buck.
"A few reserves have been set aside to protect wild relatives of crop species, and national gene banks have been set up in some 60 countries, usually keeping seeds to save space. Sixty thousand strains of rice, half the world's total, are stored at the International Rice Research Institute in the Philippines, 12,000 types of wheat and maize from 47 countries are kept at the International Maize and Wheat Improvement Center in Mexico" (Lean et. al. 132). But stores are costly and can never replicate the wild. Seeds cannot be stored forever without deteriorating, and are vulnerable to disease. There is considerable danger of creeping attrition through loss of viability through faults in storage. Moreover massive genetic resources remain completely vulnerable to accidental destruction if their survival depends substantially on high technology. A mere refrigerator failure could destroy an evolutionary heritage. We cannot depend on such processes to conserve the genetic heritage over evolutionary time.
Patenting, Intellectual Property Rights and Corporate Greed
Now that the enormous value of genetic resources is being realized, countries and companies are fighting over who owns them. The U.S. still remains to ratify the Rio Biodiversity convention because of calculating expediency about intellectual property rights over both modified organisms and natural ones taken from their home habitat and culture.
Some developed and developing countries regard their genetic resources as their property and try to stop them being exported. Some, including the US, claim proprietorial rights over all the genetic material they keep from anywhere in the world. Private companies are buying up seed firms; 10 of them control a third of all the cereal crop species listed by the Organization for Economic Cooperation and Development. They may jettison the less profitable species, even though these may have huge genetic potential and are particularly useful on specialized terrain. As seed and chemical companies combine, fears that they will design crops that require their pesticides - and only theirs - to fight off disease have been realized. A particular example is Monsanto which has out grown and taken over seed companies and now manufactures a variety of agricultural genetically-engineered strains which must be grown using Monsanto herbicides. The invention of terminator gene now threatens to make all such genetically-engineered strains non-viable in terms of the continuity of life. The patenting of species and the control of the seed markets by agrochemical companies could become the death knell for the genetic heritage, especially of domesticated species as it marks off the vast productive areas of the planet to genetic oblivion, and a possibly terminal fate for humankind.
Policy and Planning Documents:
These documents set out a world biodiversity strategy and assessment coordinated by IUCN conservation union and UNEP. They are intended to guide world policy planners in preserving biodiversity globally, so form a good basis for considering more effective policies and where existing plans have failed to be activated.
Extinction and Survival:
Values and Ethics of Biodiversity:
Ecofeminism, Deep Ecology, Biophilia, Green Eschatology
Eve, the Fall from Eden and Biodiversity
News and Comment:
Patenting and Intellectual Property
A Case: Genetic engineering and Biodiversity
Genetic engineering depends on being able to splice genes from one living organism or species into another. To be able to utilize the potential horizons of gene technology, we need to preserve as much of the biodiversity as possible now, because it is from other existing organisms that we extract the genes for existing biosynthetic pathways to splice into new arrangements. Reduce the biodiversity and the future of genetic engineering is as much reduced as that of evolution itself. However the use of genetically engineered species in the place of natural diversity threatens the very biodiversity it depends upon.
Environmental Organizations Online
Sample Plant-derived Drugs and their Uses
Meanwhile the wildlife massacre continues, interrupting 4 billion years of evolution.
3rd millennium Diversity Updates (there are more spread through the other biodiversity pages)