Krell
November 8th, 2005, 04:53 PM
Life on Earth is in the throes of a new wave of mass extinction, unlike anything since the demise of the dinosaurs. In the last 500 years, 844 species - like the passenger pigeon (http://www.newscientist.com/channel/life/endangered-species/mg16922764.000), auk (http://www.newscientist.com/channel/life/endangered-species/mg16422105.800), thylacine (http://www.newscientist.com/channel/life/endangered-species/mg17022915.100), and quagga (http://www.newscientist.com/channel/life/endangered-species/mg13217971.300) - are known to have died out, and up to 16,000 others are now known to be threatened. Two thirds of turtles could be gone by the 2025, great apes (http://www.newscientist.com/channel/life/endangered-species/dn3593) have recently declined by over 50% in parts of Africa, half of marsupials (http://www.newscientist.com/channel/life/endangered-species/mg14519624.200) and one in three amphibians (http://www.newscientist.com/channel/life/endangered-species/mg18424701.300) are in jeopardy, and a staggering 40% of Asia’s plants and animals (http://www.newscientist.com/channel/life/endangered-species/dn3973) could soon be lost.
But this may only be a fraction of the true number (http://www.newscientist.com/channel/life/endangered-species/mg18324652.000) facing extinction. Though only 1.5 million species have been described, there could be between 5 to 30 million in total. Of these, some experts predict that one could be falling extinct every 20 minutes - or 27,000 a year.
Conservationists argue that humans have an ethical obligation (http://www.newscientist.com/channel/life/endangered-species/mg18625025.700) to protect other species, that diversity and natural beauty are highly prized (http://www.newscientist.com/channel/life/endangered-species/mg17423405.300) by mankind, and that biodiversity is a vital resource (http://www.newscientist.com/channel/life/endangered-species/mg18624934.700): we rely on ecosystems (http://www.newscientist.com/channel/life/endangered-species/mg15921475.000) to provide food, oxygen and natural resources, recycle wastes and fertilise soils for agriculture. The total value of services provided to man (http://www.newscientist.com/channel/life/endangered-species/mg16121725.100) by nature has been estimated at $33 trillion annually (http://www.newscientist.com/channel/life/endangered-species/mg15420821.300).
Plants and animals are also an essential source of new foods (http://www.newscientist.com/channel/life/endangered-species/mg16722544.600) and medicines (http://www.newscientist.com/channel/life/endangered-species/mg16922832.500) - up to 20,000 plants (http://www.newscientist.com/channel/life/endangered-species/mg16622333.900) are used in medicines worldwide. Preserving species could help protect us (http://www.newscientist.com/channel/life/endangered-species/dn7945) from disease.
Sixth wave
Natural disasters and processes were behind the five major mass extinctions (http://www.newscientist.com/channel/life/endangered-species/mg16422167.700) in geological history, but the current "sixth extinction (http://www.newscientist.com/channel/life/endangered-species/mg14920194.300)" is caused by success of one species - humans. The six billion (and counting (http://www.newscientist.com/channel/life/endangered-species/dn1108)) people crowding the Earth (http://www.newscientist.com/channel/life/endangered-species/mg17823905.200), are driving out (http://www.newscientist.com/channel/life/endangered-species/dn1529) biodiversity in a variety of ways.
Species form (http://www.newscientist.com/channel/life/endangered-species/mg15821389.000) and die out (http://www.newscientist.com/channel/life/endangered-species/mg13117862.300) naturally as a part of evolution. However, many experts argue the current extinction rate is as much as 100 or 1000 times higher than the "background (http://www.newscientist.com/channel/life/endangered-species/mg17924094.700)" rate. Bird (http://www.newscientist.com/channel/life/endangered-species/mg14619724.700) extinctions were the first to hint at this, but in 2004 (http://www.newscientist.com/channel/life/endangered-species/dn4797), studies of declining butterflies and plants confirmed it.
Humans began to destroy ecosystems in a major way about 10,000 years ago with the development of agriculture (http://www.newscientist.com/channel/life/endangered-species/mg12617141.100). But within the last 100,000 years, the hunting and burning (http://www.newscientist.com/channel/life/endangered-species/dn4028) practices of Palaeolithic people (http://www.newscientist.com/channel/life/endangered-species/dn848), along with climate change (http://www.newscientist.com/channel/life/endangered-species/dn6726), drove many large mammals and birds to extinction. North- (http://www.newscientist.com/channel/life/endangered-species/mg15420774.600) and South America and Australia (http://www.newscientist.com/channel/life/endangered-species/mg17924071.800) lost up to 86% of large mammals soon after humans arrived - species such as giant wombats (http://www.newscientist.com/channel/life/endangered-species/mg17924142.100), killer ducks (http://www.newscientist.com/channel/life/endangered-species/mg16622404.800), ground sloths (http://www.newscientist.com/channel/life/endangered-species/mg15320652.500), mammoths (http://www.newscientist.com/channel/life/endangered-species/mg17022894.300), sabre-tooth cats (http://www.newscientist.com/channel/life/endangered-species/mg16522233.800) and moas (http://www.newscientist.com/channel/life/endangered-species/mg17924121.300).
Habitat losses
The most common reason for extinction is habitat loss. Ecosystems from wetlands (http://www.newscientist.com/channel/life/endangered-species/mg17022910.300) to prairies (http://www.newscientist.com/channel/life/endangered-species/mg17123076.000) and cloud forests (http://www.newscientist.com/channel/life/endangered-species/dn1451) to coral reefs (http://www.newscientist.com/channel/life/endangered-species/mg17924050.700) are being cleared or degraded for crops, cattle (http://www.newscientist.com/channel/life/endangered-species/mg18224421.700), roads (http://www.newscientist.com/channel/life/endangered-species/mg16922763.900) and development. Even fragmenting habitats (http://www.newscientist.com/channel/life/endangered-species/mg18024201.700) with roads (http://www.newscientist.com/channel/life/endangered-species/mg17423471.100) or dams (http://www.newscientist.com/channel/life/endangered-species/dn4491) can make species more vulnerable (http://www.newscientist.com/channel/life/endangered-species/mg17423471.100). Fragmentation reduces population size and increases inbreeding (http://www.newscientist.com/channel/life/endangered-species/mg18024175.100), increases disease (http://www.newscientist.com/channel/life/endangered-species/mg16922792.900) and opens access for poachers (http://www.newscientist.com/channel/life/endangered-species/dn4109).
The Amazonian rainforest is today being cleared at rate of 24,000 km2 per year (http://www.newscientist.com/channel/life/endangered-species/mg18825210.200) - equivalent to New York City’s Central Park being destroyed every hour. Worldwide, 90,000 km2 of forest is cleared annually (http://www.newscientist.com/channel/life/endangered-species/mg17723805.400).
In East Africa (http://www.newscientist.com/channel/life/endangered-species/mg18725184.300) deforestation is destroying game parks, Singapore has lost 95% (http://www.newscientist.com/channel/life/endangered-species/dn3973) of its tropical forests, South East Asia may lose 74% by 2100. More than quarter of Earth’s land (http://www.newscientist.com/channel/life/endangered-species/mg18624934.400) is under cultivation and in 54 countries 90% of forests have been felled.
Alien invaders
Some endangered species also have to contend with exotic invaders (http://www.newscientist.com/channel/life/endangered-species/mg16021595.800) - the second biggest threat (http://www.newscientist.com/channel/life/endangered-species/dn2214) to rare species. Introduced species prey on them (http://www.newscientist.com/channel/life/endangered-species/mg18324541.500), eat their food, infect them or otherwise disrupt them (http://www.newscientist.com/channel/life/endangered-species/mg17823890.700). Human seafarers have spread cats, dogs, rats, foxes, rabbits and weasels to new places, contributing to the McDonaldisation (http://www.newscientist.com/channel/life/endangered-species/mg15821405.500) of Earth’s biota.
In Australia, rabbits (http://www.newscientist.com/channel/life/endangered-species/mg17523550.300) and foxes are driving native marsupials (http://www.newscientist.com/channel/life/endangered-species/mg17223175.200) to extinction (http://www.newscientist.com/channel/life/endangered-species/mg17723795.200); In New Zealand, weasels have been pushing the flightless Kakapo (http://www.newscientist.com/channel/life/endangered-species/mg17423454.500) parrot to its doom; In North America, tiny European zebra mussels (http://www.newscientist.com/channel/life/endangered-species/dn1204) arrived in the 1980s with shipping, and clog waterways; In the US, once-ubiquitous chestnuts were decimated by an introduced blight (http://www.newscientist.com/channel/life/endangered-species/mg18224505.400). In Kenya’s Lake Victoria, the Nile perch (http://www.newscientist.com/channel/life/endangered-species/mg18124365.300) has miraculously managed to eat its way through 200 cichlid fish species since 1959.And in Maryland, US, the voracious south-east Asian snakehead fish (http://www.newscientist.com/channel/life/endangered-species/mg18024225.900) has been chomping its way through native fish and waterfowl since 2002 (http://www.newscientist.com/channel/life/endangered-species/mg17523511.700).
Often exotic species, such as the cane toad (http://www.newscientist.com/channel/life/endangered-species/mg12517090.600), have even been introduced intentionally (http://www.newscientist.com/channel/life/endangered-species/mg12917596.900), to control other species with disastrous consequences. One unusual way to eradicate (http://www.newscientist.com/channel/life/endangered-species/mg16922831.400) invaders could be for people to eat them (http://www.newscientist.com/channel/earth/mg18725161.500).
Exploitation
Exploitation - hunting, collecting, fishing or trading - is another factor driving extinctions. American bison (http://www.newscientist.com/channel/life/endangered-species/mg17523586.300) were hunted down from a population of 30 million before Europeans arrived, to just 750 animals in 1890. Whales were exploited so fiercely (http://www.newscientist.com/channel/life/endangered-species/dn1621) that the International Whaling Commission (http://www.newscientist.com/channel/life/endangered-species/dn6198) voted in 1986 to place a moratorium (http://www.newscientist.com/channel/life/endangered-species/mg18625043.900) on most whaling.
Blue whales (http://www.newscientist.com/channel/life/endangered-species/dn2433), for example, were hunted down from a population of perhaps 300,000 to just a few thousand by the 1960s.
Today we continue to rape the oceans (http://www.newscientist.com/channel/life/endangered-species/mg17924060.300) through overfishing. The UN claims that 15 of the top 17 fisheries are in decline. Exploited species include: the tuna (http://www.newscientist.com/channel/life/endangered-species/mg17423441.900), swordfish (http://www.newscientist.com/channel/life/endangered-species/dn6455), red snapper (http://www.newscientist.com/channel/life/endangered-species/mg18324562.900), Atlantic salmon (http://www.newscientist.com/channel/life/endangered-species/dn817), Atlantic cod (http://www.newscientist.com/channel/life/endangered-species/mg18825194.400), sharks (http://www.newscientist.com/channel/life/endangered-species/mg18725183.300) and lobsters (http://www.newscientist.com/channel/life/endangered-species/mg16422182.600). Now, overfishing of the smaller species (http://www.newscientist.com/channel/life/endangered-species/mg15721210.200) that fleets have switched to may inhibit the recovery (http://www.newscientist.com/channel/life/endangered-species/mg18024251.200) of the more-prized species that prey on them.
Canada’s Atlantic cod fishery was closed (http://www.newscientist.com/channel/life/endangered-species/mg17924140.600) in 1992 (http://www.newscientist.com/channel/life/endangered-species/mg13318110.400) following its collapse (http://www.newscientist.com/channel/life/endangered-species/mg14719953.400). Better management (http://www.newscientist.com/channel/life/endangered-species/dn1708) and stock modelling (http://www.newscientist.com/channel/life/endangered-species/mg17723875.100) may help reverse the trend, but others argue that many fisheries are already doomed (http://www.newscientist.com/channel/life/endangered-species/dn1940).
Other species are unintentionally killed as bycatch, by drift nets (http://www.newscientist.com/channel/life/endangered-species/mg18424702.200), longlines (http://www.newscientist.com/channel/life/endangered-species/mg16021571.900) and deep-sea trawlers (http://www.newscientist.com/channel/life/endangered-species/dn4097). Surveys reveal that 300,000 dolphins and small whales (http://www.newscientist.com/channel/life/endangered-species/dn7501) and as many as half of all remaining turtles (http://www.newscientist.com/channel/life/endangered-species/dn4677) are snared as bycatch each year. Overfishing could even put a strain on terrestrial wildlife (http://www.newscientist.com/channel/life/endangered-species/dn6661).
Another significant challenge to conservation is the international trade in rare species. Second only to the illegal drug trade (http://www.newscientist.com/channel/life/endangered-species/dn2413), it is thought to be worth more than illegal arms, and may net $10 billion a year. Tropical fish (http://www.newscientist.com/channel/life/endangered-species/mg16822632.800), birds (http://www.newscientist.com/channel/life/endangered-species/mg15420801.200) (particularly parrots (http://www.newscientist.com/channel/life/endangered-species/dn836)), and other animals are captured and sold as pets (http://www.newscientist.com/channel/life/endangered-species/dn7529). Some – like turtles (http://www.newscientist.com/channel/life/endangered-species/mg17123074.800), whales (http://www.newscientist.com/channel/life/endangered-species/dn6548) and sharks (http://www.newscientist.com/channel/life/endangered-species/dn3068) - are prized as delicacies.
Others - such as tigers (http://www.newscientist.com/channel/life/endangered-species/mg18624963.900), rhinos (http://www.newscientist.com/channel/life/endangered-species/mg14920150.800) and saiga (http://www.newscientist.com/channel/life/endangered-species/dn3376) - are killed to supply bones (http://www.newscientist.com/channel/life/endangered-species/mg18825193.400), gall bladders (http://www.newscientist.com/channel/life/endangered-species/mg13318131.100), horns and other body parts for traditional medicine (http://www.newscientist.com/channel/life/endangered-species/mg15721154.600). Horns, feathers, eggs (http://www.newscientist.com/channel/life/endangered-species/mg15420818.500) and other trophies are smuggled to unscrupulous collectors (http://www.newscientist.com/channel/life/endangered-species/dn1937). Trade in elephant ivory was banned in 1990 (http://www.newscientist.com/channel/life/endangered-species/mg18324623.000), but despite the ban (http://www.newscientist.com/channel/life/endangered-species/dn3046) 4000 are still killed illegally (http://www.newscientist.com/channel/life/endangered-species/dn6413) each year.
The UN’s Convention on International Trade in Endangered Species (CITES) was set up in 1975 to stem the flow. Another body, TRAFFIC (http://www.newscientist.com/channel/life/endangered-species/mg14619790.900), monitors trade in rare species. One US forensics lab (http://www.newscientist.com/channel/life/endangered-species/mg16522224.600) is dedicated to uncovering the illegal trade. Detection kits (http://www.newscientist.com/channel/life/endangered-species/dn6739) for bear tissue and different kinds of fur (http://www.newscientist.com/channel/life/endangered-species/dn3115) may help uncover illegal imports. However, some experts argue that we must allow limited trade (http://www.newscientist.com/channel/life/endangered-species/mg18424701.900) of species in order to save them.
Pollution
Pollution is another serious issue. If it does not kill animals outright, pollution can affect reproduction (http://www.newscientist.com/channel/life/endangered-species/mg18625034.000), mess with sexual development (http://www.newscientist.com/channel/life/endangered-species/mg15821373.900) and trigger bizarre behaviour (http://www.newscientist.com/channel/life/endangered-species/dn6343).
Mercury (http://www.newscientist.com/channel/life/endangered-species/mg18524913.900), dioxins (http://www.newscientist.com/channel/life/endangered-species/mg16822590.400), flame retardants (http://www.newscientist.com/channel/life/endangered-species/mg18224511.500), synthetic hormone (http://www.newscientist.com/channel/life/endangered-species/dn7440), pesticides (http://www.newscientist.com/channel/life/endangered-species/mg16221803.100) and other hydrocarbons such as DDT (http://www.newscientist.com/channel/life/endangered-species/mg17723810.700) and PCBs (http://www.newscientist.com/channel/life/endangered-species/mg17323254.100) are ubiquitous and carried far and wide (http://www.newscientist.com/channel/life/endangered-species/mg18725093.900). Carcinogenic pollutants (http://www.newscientist.com/channel/life/endangered-species/dn1983) are behind cancers in Canadian beluga whales. Sewage (http://www.newscientist.com/channel/life/endangered-species/dn2416) is ravaging Caribbean corals, while acid rain (http://www.newscientist.com/channel/life/endangered-species/mg17423437.700) is killing fish and trees in Europe. Radioactive waste is found throughout oceans (http://www.newscientist.com/channel/life/endangered-species/mg15921454.500) and ecosystems (http://www.newscientist.com/channel/life/endangered-species/mg16822601.400).
Oil spills continue to kill seabirds, marine and coastal life in regions such as Spain (http://www.newscientist.com/channel/life/endangered-species/dn4100), Pakistan (http://www.newscientist.com/channel/life/endangered-species/dn4077) and the Galapagos islands (http://www.newscientist.com/channel/life/endangered-species/dn2372). Between 1993 and 2002, 580,000 tonnes of oil (http://www.newscientist.com/channel/life/endangered-species/dn4153) spilt into the sea in 470 separate accidents.
Conservation measures
The World Conservation Union (http://www.newscientist.com/channel/life/endangered-species/mg18424796.300) (IUCN) publishes the Red List (http://www.newscientist.com/channel/life/endangered-species/dn6684) - an annual index of threatened species. The IUCN, governments and conservationists try to protect these species by fencing them off and educating (http://www.newscientist.com/channel/life/endangered-species/mg18524854.300) local people.
In 1872 Yellowstone (http://www.newscientist.com/channel/life/endangered-species/dn6730) National Park, in the US, became the world’s first modern reserve. During the last century 44,000 protected areas were designated, covering 10% of Earth’s land. Marine reserves only cover 1% of oceans, and more are needed (http://www.newscientist.com/channel/life/endangered-species/dn439).
The identification of biodiversity hotspots (http://www.newscientist.com/channel/life/endangered-species/mg18524854.200) may help focus resources. Ecotourism (http://www.newscientist.com/channel/life/endangered-species/dn6293) may also be part of the solution, but could be part of the problem (http://www.newscientist.com/channel/life/endangered-species/dn4733) too. Returning the stewardship of forest reserves and other habitats to their indigenous inhabitants (http://www.newscientist.com/channel/life/endangered-species/mg18324581.100) could help.
In Africa (http://www.newscientist.com/channel/life/endangered-species/mg16722514.300), 2 million km2 is designated as protected: reserves such as Aberdare (http://www.newscientist.com/channel/life/endangered-species/dn2193), Tsavo (http://www.newscientist.com/channel/life/endangered-species/dn2193) and the Masai Mara (http://www.newscientist.com/channel/life/endangered-species/mg14719934.100) in Kenya; Quiçama (http://www.newscientist.com/channel/life/endangered-species/dn2776) in Angola; Kruger (http://www.newscientist.com/channel/life/endangered-species/mg18825193.800) in South Africa; Garamba (http://www.newscientist.com/channel/life/endangered-species/mg18725096.400) and Virunga (http://www.newscientist.com/channel/life/endangered-species/dn4109) in Congo; Queen Elizabeth (http://www.newscientist.com/channel/life/endangered-species/dn6818) in Uganda and the Serengeti (http://www.newscientist.com/channel/life/endangered-species/mg18725184.300) in Tanzania. In 2002 Brazil created the vast Tumucumaque National Park (http://www.newscientist.com/channel/life/endangered-species/dn2712), the largest tropical forest reserve in the world, the same year that Australia created the world’s largest marine reserve (http://www.newscientist.com/channel/life/endangered-species/dn2904).
Reintroducing species such as golden tamarin moneys (http://www.newscientist.com/channel/life/endangered-species/mg17022850.500), wolves (http://www.newscientist.com/channel/life/endangered-species/mg17823910.600) and condors (http://www.newscientist.com/channel/life/endangered-species/mg17623635.700), has been a success. Some researchers even advocate reintroducing large animals (http://www.newscientist.com/channel/life/endangered-species/mg17123104.800) such as lions and elephants (http://www.newscientist.com/channel/life/endangered-species/dn7862) to the US and wolves (http://www.newscientist.com/channel/life/endangered-species/mg18324581.100) to the UK.
Failing these methods, if we collect genetic material now, we may be able to reincarnate extinct species (http://www.newscientist.com/channel/life/endangered-species/mg18224526.100) by cloning them in the future.
John Pickrell, 20 October 2005
http://www.newscientist.com/channel/life/endangered-species
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But this may only be a fraction of the true number (http://www.newscientist.com/channel/life/endangered-species/mg18324652.000) facing extinction. Though only 1.5 million species have been described, there could be between 5 to 30 million in total. Of these, some experts predict that one could be falling extinct every 20 minutes - or 27,000 a year.
Conservationists argue that humans have an ethical obligation (http://www.newscientist.com/channel/life/endangered-species/mg18625025.700) to protect other species, that diversity and natural beauty are highly prized (http://www.newscientist.com/channel/life/endangered-species/mg17423405.300) by mankind, and that biodiversity is a vital resource (http://www.newscientist.com/channel/life/endangered-species/mg18624934.700): we rely on ecosystems (http://www.newscientist.com/channel/life/endangered-species/mg15921475.000) to provide food, oxygen and natural resources, recycle wastes and fertilise soils for agriculture. The total value of services provided to man (http://www.newscientist.com/channel/life/endangered-species/mg16121725.100) by nature has been estimated at $33 trillion annually (http://www.newscientist.com/channel/life/endangered-species/mg15420821.300).
Plants and animals are also an essential source of new foods (http://www.newscientist.com/channel/life/endangered-species/mg16722544.600) and medicines (http://www.newscientist.com/channel/life/endangered-species/mg16922832.500) - up to 20,000 plants (http://www.newscientist.com/channel/life/endangered-species/mg16622333.900) are used in medicines worldwide. Preserving species could help protect us (http://www.newscientist.com/channel/life/endangered-species/dn7945) from disease.
Sixth wave
Natural disasters and processes were behind the five major mass extinctions (http://www.newscientist.com/channel/life/endangered-species/mg16422167.700) in geological history, but the current "sixth extinction (http://www.newscientist.com/channel/life/endangered-species/mg14920194.300)" is caused by success of one species - humans. The six billion (and counting (http://www.newscientist.com/channel/life/endangered-species/dn1108)) people crowding the Earth (http://www.newscientist.com/channel/life/endangered-species/mg17823905.200), are driving out (http://www.newscientist.com/channel/life/endangered-species/dn1529) biodiversity in a variety of ways.
Species form (http://www.newscientist.com/channel/life/endangered-species/mg15821389.000) and die out (http://www.newscientist.com/channel/life/endangered-species/mg13117862.300) naturally as a part of evolution. However, many experts argue the current extinction rate is as much as 100 or 1000 times higher than the "background (http://www.newscientist.com/channel/life/endangered-species/mg17924094.700)" rate. Bird (http://www.newscientist.com/channel/life/endangered-species/mg14619724.700) extinctions were the first to hint at this, but in 2004 (http://www.newscientist.com/channel/life/endangered-species/dn4797), studies of declining butterflies and plants confirmed it.
Humans began to destroy ecosystems in a major way about 10,000 years ago with the development of agriculture (http://www.newscientist.com/channel/life/endangered-species/mg12617141.100). But within the last 100,000 years, the hunting and burning (http://www.newscientist.com/channel/life/endangered-species/dn4028) practices of Palaeolithic people (http://www.newscientist.com/channel/life/endangered-species/dn848), along with climate change (http://www.newscientist.com/channel/life/endangered-species/dn6726), drove many large mammals and birds to extinction. North- (http://www.newscientist.com/channel/life/endangered-species/mg15420774.600) and South America and Australia (http://www.newscientist.com/channel/life/endangered-species/mg17924071.800) lost up to 86% of large mammals soon after humans arrived - species such as giant wombats (http://www.newscientist.com/channel/life/endangered-species/mg17924142.100), killer ducks (http://www.newscientist.com/channel/life/endangered-species/mg16622404.800), ground sloths (http://www.newscientist.com/channel/life/endangered-species/mg15320652.500), mammoths (http://www.newscientist.com/channel/life/endangered-species/mg17022894.300), sabre-tooth cats (http://www.newscientist.com/channel/life/endangered-species/mg16522233.800) and moas (http://www.newscientist.com/channel/life/endangered-species/mg17924121.300).
Habitat losses
The most common reason for extinction is habitat loss. Ecosystems from wetlands (http://www.newscientist.com/channel/life/endangered-species/mg17022910.300) to prairies (http://www.newscientist.com/channel/life/endangered-species/mg17123076.000) and cloud forests (http://www.newscientist.com/channel/life/endangered-species/dn1451) to coral reefs (http://www.newscientist.com/channel/life/endangered-species/mg17924050.700) are being cleared or degraded for crops, cattle (http://www.newscientist.com/channel/life/endangered-species/mg18224421.700), roads (http://www.newscientist.com/channel/life/endangered-species/mg16922763.900) and development. Even fragmenting habitats (http://www.newscientist.com/channel/life/endangered-species/mg18024201.700) with roads (http://www.newscientist.com/channel/life/endangered-species/mg17423471.100) or dams (http://www.newscientist.com/channel/life/endangered-species/dn4491) can make species more vulnerable (http://www.newscientist.com/channel/life/endangered-species/mg17423471.100). Fragmentation reduces population size and increases inbreeding (http://www.newscientist.com/channel/life/endangered-species/mg18024175.100), increases disease (http://www.newscientist.com/channel/life/endangered-species/mg16922792.900) and opens access for poachers (http://www.newscientist.com/channel/life/endangered-species/dn4109).
The Amazonian rainforest is today being cleared at rate of 24,000 km2 per year (http://www.newscientist.com/channel/life/endangered-species/mg18825210.200) - equivalent to New York City’s Central Park being destroyed every hour. Worldwide, 90,000 km2 of forest is cleared annually (http://www.newscientist.com/channel/life/endangered-species/mg17723805.400).
In East Africa (http://www.newscientist.com/channel/life/endangered-species/mg18725184.300) deforestation is destroying game parks, Singapore has lost 95% (http://www.newscientist.com/channel/life/endangered-species/dn3973) of its tropical forests, South East Asia may lose 74% by 2100. More than quarter of Earth’s land (http://www.newscientist.com/channel/life/endangered-species/mg18624934.400) is under cultivation and in 54 countries 90% of forests have been felled.
Alien invaders
Some endangered species also have to contend with exotic invaders (http://www.newscientist.com/channel/life/endangered-species/mg16021595.800) - the second biggest threat (http://www.newscientist.com/channel/life/endangered-species/dn2214) to rare species. Introduced species prey on them (http://www.newscientist.com/channel/life/endangered-species/mg18324541.500), eat their food, infect them or otherwise disrupt them (http://www.newscientist.com/channel/life/endangered-species/mg17823890.700). Human seafarers have spread cats, dogs, rats, foxes, rabbits and weasels to new places, contributing to the McDonaldisation (http://www.newscientist.com/channel/life/endangered-species/mg15821405.500) of Earth’s biota.
In Australia, rabbits (http://www.newscientist.com/channel/life/endangered-species/mg17523550.300) and foxes are driving native marsupials (http://www.newscientist.com/channel/life/endangered-species/mg17223175.200) to extinction (http://www.newscientist.com/channel/life/endangered-species/mg17723795.200); In New Zealand, weasels have been pushing the flightless Kakapo (http://www.newscientist.com/channel/life/endangered-species/mg17423454.500) parrot to its doom; In North America, tiny European zebra mussels (http://www.newscientist.com/channel/life/endangered-species/dn1204) arrived in the 1980s with shipping, and clog waterways; In the US, once-ubiquitous chestnuts were decimated by an introduced blight (http://www.newscientist.com/channel/life/endangered-species/mg18224505.400). In Kenya’s Lake Victoria, the Nile perch (http://www.newscientist.com/channel/life/endangered-species/mg18124365.300) has miraculously managed to eat its way through 200 cichlid fish species since 1959.And in Maryland, US, the voracious south-east Asian snakehead fish (http://www.newscientist.com/channel/life/endangered-species/mg18024225.900) has been chomping its way through native fish and waterfowl since 2002 (http://www.newscientist.com/channel/life/endangered-species/mg17523511.700).
Often exotic species, such as the cane toad (http://www.newscientist.com/channel/life/endangered-species/mg12517090.600), have even been introduced intentionally (http://www.newscientist.com/channel/life/endangered-species/mg12917596.900), to control other species with disastrous consequences. One unusual way to eradicate (http://www.newscientist.com/channel/life/endangered-species/mg16922831.400) invaders could be for people to eat them (http://www.newscientist.com/channel/earth/mg18725161.500).
Exploitation
Exploitation - hunting, collecting, fishing or trading - is another factor driving extinctions. American bison (http://www.newscientist.com/channel/life/endangered-species/mg17523586.300) were hunted down from a population of 30 million before Europeans arrived, to just 750 animals in 1890. Whales were exploited so fiercely (http://www.newscientist.com/channel/life/endangered-species/dn1621) that the International Whaling Commission (http://www.newscientist.com/channel/life/endangered-species/dn6198) voted in 1986 to place a moratorium (http://www.newscientist.com/channel/life/endangered-species/mg18625043.900) on most whaling.
Blue whales (http://www.newscientist.com/channel/life/endangered-species/dn2433), for example, were hunted down from a population of perhaps 300,000 to just a few thousand by the 1960s.
Today we continue to rape the oceans (http://www.newscientist.com/channel/life/endangered-species/mg17924060.300) through overfishing. The UN claims that 15 of the top 17 fisheries are in decline. Exploited species include: the tuna (http://www.newscientist.com/channel/life/endangered-species/mg17423441.900), swordfish (http://www.newscientist.com/channel/life/endangered-species/dn6455), red snapper (http://www.newscientist.com/channel/life/endangered-species/mg18324562.900), Atlantic salmon (http://www.newscientist.com/channel/life/endangered-species/dn817), Atlantic cod (http://www.newscientist.com/channel/life/endangered-species/mg18825194.400), sharks (http://www.newscientist.com/channel/life/endangered-species/mg18725183.300) and lobsters (http://www.newscientist.com/channel/life/endangered-species/mg16422182.600). Now, overfishing of the smaller species (http://www.newscientist.com/channel/life/endangered-species/mg15721210.200) that fleets have switched to may inhibit the recovery (http://www.newscientist.com/channel/life/endangered-species/mg18024251.200) of the more-prized species that prey on them.
Canada’s Atlantic cod fishery was closed (http://www.newscientist.com/channel/life/endangered-species/mg17924140.600) in 1992 (http://www.newscientist.com/channel/life/endangered-species/mg13318110.400) following its collapse (http://www.newscientist.com/channel/life/endangered-species/mg14719953.400). Better management (http://www.newscientist.com/channel/life/endangered-species/dn1708) and stock modelling (http://www.newscientist.com/channel/life/endangered-species/mg17723875.100) may help reverse the trend, but others argue that many fisheries are already doomed (http://www.newscientist.com/channel/life/endangered-species/dn1940).
Other species are unintentionally killed as bycatch, by drift nets (http://www.newscientist.com/channel/life/endangered-species/mg18424702.200), longlines (http://www.newscientist.com/channel/life/endangered-species/mg16021571.900) and deep-sea trawlers (http://www.newscientist.com/channel/life/endangered-species/dn4097). Surveys reveal that 300,000 dolphins and small whales (http://www.newscientist.com/channel/life/endangered-species/dn7501) and as many as half of all remaining turtles (http://www.newscientist.com/channel/life/endangered-species/dn4677) are snared as bycatch each year. Overfishing could even put a strain on terrestrial wildlife (http://www.newscientist.com/channel/life/endangered-species/dn6661).
Another significant challenge to conservation is the international trade in rare species. Second only to the illegal drug trade (http://www.newscientist.com/channel/life/endangered-species/dn2413), it is thought to be worth more than illegal arms, and may net $10 billion a year. Tropical fish (http://www.newscientist.com/channel/life/endangered-species/mg16822632.800), birds (http://www.newscientist.com/channel/life/endangered-species/mg15420801.200) (particularly parrots (http://www.newscientist.com/channel/life/endangered-species/dn836)), and other animals are captured and sold as pets (http://www.newscientist.com/channel/life/endangered-species/dn7529). Some – like turtles (http://www.newscientist.com/channel/life/endangered-species/mg17123074.800), whales (http://www.newscientist.com/channel/life/endangered-species/dn6548) and sharks (http://www.newscientist.com/channel/life/endangered-species/dn3068) - are prized as delicacies.
Others - such as tigers (http://www.newscientist.com/channel/life/endangered-species/mg18624963.900), rhinos (http://www.newscientist.com/channel/life/endangered-species/mg14920150.800) and saiga (http://www.newscientist.com/channel/life/endangered-species/dn3376) - are killed to supply bones (http://www.newscientist.com/channel/life/endangered-species/mg18825193.400), gall bladders (http://www.newscientist.com/channel/life/endangered-species/mg13318131.100), horns and other body parts for traditional medicine (http://www.newscientist.com/channel/life/endangered-species/mg15721154.600). Horns, feathers, eggs (http://www.newscientist.com/channel/life/endangered-species/mg15420818.500) and other trophies are smuggled to unscrupulous collectors (http://www.newscientist.com/channel/life/endangered-species/dn1937). Trade in elephant ivory was banned in 1990 (http://www.newscientist.com/channel/life/endangered-species/mg18324623.000), but despite the ban (http://www.newscientist.com/channel/life/endangered-species/dn3046) 4000 are still killed illegally (http://www.newscientist.com/channel/life/endangered-species/dn6413) each year.
The UN’s Convention on International Trade in Endangered Species (CITES) was set up in 1975 to stem the flow. Another body, TRAFFIC (http://www.newscientist.com/channel/life/endangered-species/mg14619790.900), monitors trade in rare species. One US forensics lab (http://www.newscientist.com/channel/life/endangered-species/mg16522224.600) is dedicated to uncovering the illegal trade. Detection kits (http://www.newscientist.com/channel/life/endangered-species/dn6739) for bear tissue and different kinds of fur (http://www.newscientist.com/channel/life/endangered-species/dn3115) may help uncover illegal imports. However, some experts argue that we must allow limited trade (http://www.newscientist.com/channel/life/endangered-species/mg18424701.900) of species in order to save them.
Pollution
Pollution is another serious issue. If it does not kill animals outright, pollution can affect reproduction (http://www.newscientist.com/channel/life/endangered-species/mg18625034.000), mess with sexual development (http://www.newscientist.com/channel/life/endangered-species/mg15821373.900) and trigger bizarre behaviour (http://www.newscientist.com/channel/life/endangered-species/dn6343).
Mercury (http://www.newscientist.com/channel/life/endangered-species/mg18524913.900), dioxins (http://www.newscientist.com/channel/life/endangered-species/mg16822590.400), flame retardants (http://www.newscientist.com/channel/life/endangered-species/mg18224511.500), synthetic hormone (http://www.newscientist.com/channel/life/endangered-species/dn7440), pesticides (http://www.newscientist.com/channel/life/endangered-species/mg16221803.100) and other hydrocarbons such as DDT (http://www.newscientist.com/channel/life/endangered-species/mg17723810.700) and PCBs (http://www.newscientist.com/channel/life/endangered-species/mg17323254.100) are ubiquitous and carried far and wide (http://www.newscientist.com/channel/life/endangered-species/mg18725093.900). Carcinogenic pollutants (http://www.newscientist.com/channel/life/endangered-species/dn1983) are behind cancers in Canadian beluga whales. Sewage (http://www.newscientist.com/channel/life/endangered-species/dn2416) is ravaging Caribbean corals, while acid rain (http://www.newscientist.com/channel/life/endangered-species/mg17423437.700) is killing fish and trees in Europe. Radioactive waste is found throughout oceans (http://www.newscientist.com/channel/life/endangered-species/mg15921454.500) and ecosystems (http://www.newscientist.com/channel/life/endangered-species/mg16822601.400).
Oil spills continue to kill seabirds, marine and coastal life in regions such as Spain (http://www.newscientist.com/channel/life/endangered-species/dn4100), Pakistan (http://www.newscientist.com/channel/life/endangered-species/dn4077) and the Galapagos islands (http://www.newscientist.com/channel/life/endangered-species/dn2372). Between 1993 and 2002, 580,000 tonnes of oil (http://www.newscientist.com/channel/life/endangered-species/dn4153) spilt into the sea in 470 separate accidents.
Conservation measures
The World Conservation Union (http://www.newscientist.com/channel/life/endangered-species/mg18424796.300) (IUCN) publishes the Red List (http://www.newscientist.com/channel/life/endangered-species/dn6684) - an annual index of threatened species. The IUCN, governments and conservationists try to protect these species by fencing them off and educating (http://www.newscientist.com/channel/life/endangered-species/mg18524854.300) local people.
In 1872 Yellowstone (http://www.newscientist.com/channel/life/endangered-species/dn6730) National Park, in the US, became the world’s first modern reserve. During the last century 44,000 protected areas were designated, covering 10% of Earth’s land. Marine reserves only cover 1% of oceans, and more are needed (http://www.newscientist.com/channel/life/endangered-species/dn439).
The identification of biodiversity hotspots (http://www.newscientist.com/channel/life/endangered-species/mg18524854.200) may help focus resources. Ecotourism (http://www.newscientist.com/channel/life/endangered-species/dn6293) may also be part of the solution, but could be part of the problem (http://www.newscientist.com/channel/life/endangered-species/dn4733) too. Returning the stewardship of forest reserves and other habitats to their indigenous inhabitants (http://www.newscientist.com/channel/life/endangered-species/mg18324581.100) could help.
In Africa (http://www.newscientist.com/channel/life/endangered-species/mg16722514.300), 2 million km2 is designated as protected: reserves such as Aberdare (http://www.newscientist.com/channel/life/endangered-species/dn2193), Tsavo (http://www.newscientist.com/channel/life/endangered-species/dn2193) and the Masai Mara (http://www.newscientist.com/channel/life/endangered-species/mg14719934.100) in Kenya; Quiçama (http://www.newscientist.com/channel/life/endangered-species/dn2776) in Angola; Kruger (http://www.newscientist.com/channel/life/endangered-species/mg18825193.800) in South Africa; Garamba (http://www.newscientist.com/channel/life/endangered-species/mg18725096.400) and Virunga (http://www.newscientist.com/channel/life/endangered-species/dn4109) in Congo; Queen Elizabeth (http://www.newscientist.com/channel/life/endangered-species/dn6818) in Uganda and the Serengeti (http://www.newscientist.com/channel/life/endangered-species/mg18725184.300) in Tanzania. In 2002 Brazil created the vast Tumucumaque National Park (http://www.newscientist.com/channel/life/endangered-species/dn2712), the largest tropical forest reserve in the world, the same year that Australia created the world’s largest marine reserve (http://www.newscientist.com/channel/life/endangered-species/dn2904).
Reintroducing species such as golden tamarin moneys (http://www.newscientist.com/channel/life/endangered-species/mg17022850.500), wolves (http://www.newscientist.com/channel/life/endangered-species/mg17823910.600) and condors (http://www.newscientist.com/channel/life/endangered-species/mg17623635.700), has been a success. Some researchers even advocate reintroducing large animals (http://www.newscientist.com/channel/life/endangered-species/mg17123104.800) such as lions and elephants (http://www.newscientist.com/channel/life/endangered-species/dn7862) to the US and wolves (http://www.newscientist.com/channel/life/endangered-species/mg18324581.100) to the UK.
Failing these methods, if we collect genetic material now, we may be able to reincarnate extinct species (http://www.newscientist.com/channel/life/endangered-species/mg18224526.100) by cloning them in the future.
John Pickrell, 20 October 2005
http://www.newscientist.com/channel/life/endangered-species
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