2011全球保育名錄：紅豆杉瀕危、西部黑犀牛絕種

One-quarter of all the world's mammals are at risk of extinction despite conservation efforts, according to the latest update of the IUCN Red List of Threatened Species, released today. One rhinocerus subspecies has been declared Extinct in the updated list, and other rhino subspecies are teetering on the brink.

Plant species, too, are disappearing. The West Himalayan yew, Taxus contorta, which is used to produce the chemotherapy drug Taxol, has been reclassified from Vulnerable to Endangered due to over-exploitation for medicinal use and over-collection for fuel wood and fodder. The decline is continuing and in many areas will not be reversible, said the IUCN.

"This update offers both good and bad news on the status of many species around the world," said Jane Smart, director of the IUCN Global Species Programme. "We have the knowledge that conservation works if executed in a timely manner, yet, without strong political will in combination with targeted efforts and resources, the wonders of nature and the services it provides can be lost forever."

The reassessments of several rhinoceros species show that the subspecies of the black rhino in western Africa, the western black rhino, Diceros bicornis longipes, has officially been declared Extinct. These rhinos were once widespread on the central-west African savannah but were wiped out by poachers.

The subspecies of the white rhino in central Africa, the northern white rhino, Ceratotherium simum cottoni, is teetering on the brink of extinction and has been listed as Possibly Extinct in the Wild.

Simon Stuart, who chairs the IUCN Species Survival Commission, said, "In the case of both the Western Black Rhino and the Northern White Rhino the situation could have had very different results if the suggested conservation measures had been implemented. These measures must be strengthened now, specifically managing habitats in order to improve breeding performance, preventing other rhinos from fading into extinction."

The Javan rhino, Rhinoceros sondaicus, is making its last stand, as the subspecies Rhinoceros sondaicus annasmiticus is probably Extinct, following the poaching of what is thought to be the last animal in Vietnam in 2010.

The Javan rhino is not yet extinct but it is reduced to a single, tiny, declining population on the Indonesian island of Java. A lack of political support and will power for conservation efforts in many rhino habitats, international organized crime groups targeting rhinos and increasing illegal demand for rhino horns are the main threats faced by rhinos.

The Przewalski's horse, Equus ferus, is another success story, improving its status from Critically Endangered to Endangered. Originally, it was listed as Extinct in the Wild in 1996, but thanks to a captive breeding program and a successful reintroduction program, the population is now estimated at more than 300.

Global figures for 2011.2 IUCN Red List of Threatened Species:
Total Species Assessed = 61,914
Extinct = 801
Extinct in the Wild = 64
Critically Endangered = 3,879
Endangered = 5,689
Vulnerable = 10,002
Near Threatened = 4,389
Lower Risk/conservation dependent = 257 (this old category is gradually being phased out of the Red List)
Data Deficient = 9,709
Least Concern = 27,124

In recent years, many more reptile species have been assessed, including most of those found in Madagascar the island nation off the southeastern coast of Africa.

The updated Red List shows that 40 percent of Madagascar's terrestrial reptiles are threatened. The 22 Madagascan species currently identified as Critically Endangered, which include chameleons, geckoes, skinks and snakes, are now a conservation challenge.

Encouragingly, said the IUCN, there are new conservation areas being designated in Madagascar that will help conserve some of its Critically Endangered species, such as Tarzan's chameleon, Calumma tarzan, the bizarre-nosed chameleon, Calumma hafahafa, and the limbless skink, Paracontias fasika.

Plants are an essential resource for human well-being and are a critical component for wildlife habitats, yet they are still underrepresented on the IUCN Red List.

Current work underway to increase knowledge of plants includes a review of all conifers that has uncovered some "disturbing" trends, the IUCN said.

The Chinese Water Fir, Glyptostrobus pensilis, which was formerly widespread throughout China and Vietnam has moved from Endangered to Critically Endangered. The main cause of decline is the loss of habitat to expanding intensive agriculture and in China there appear to be no wild plants remaining. The largest of the recently discovered stands in Laos was killed through flooding for a newly constructed hydro scheme and very few, if any, of the trees in Vietnam produce viable seeds, so this species is rapidly moving towards becoming Extinct in the Wild.

"There are 380,000 species of plants named and described, with about 2,000 being added to the list every year. At Kew we estimate one in five of these are likely to be under threat of extinction right now, before we even factor in the impacts of climate change," says Dr. Tim Entwisle, director of conservation, living collections and estates, the Royal Botanic Gardens, Kew.

"For plants we are calibrating the Barometer of Life," he said. "For their relatives, the fungi and algae, we still have little sense of what is out there and what we are losing."

The majority of endemic flowering plants in the granitic Seychelles islands have been assessed and current studies show that of the 79 endemic species, 77 percent are at risk of extinction. Most of these are new assessments but one species, the infamous Coco de Mer, Lodoicea maldivica, has been uplisted from Vulnerable to Endangered. Known for its supposed aphrodisiac properties, the Coco de Mer faces threats from fires and illegal harvesting of its kernels. Presently, all collection and sale of its seed is highly regulated, but there is thought to be a black market trade in kernels.

The IUCN Red List keeps pace with scientific discoveries. For example, until recently only one species of manta ray was known, but new comparisons of field observations now reveal that there are actually two species of manta ray: the Reef Manta Ray, Manta alfredi, and the Giant Manta Ray, Manta birostris, both now classified as Vulnerable.

The results of the assessments of all species of scombrids (tunas, bonitos, mackerels and Spanish mackerels) and billfishes (swordfish and marlins) were published recently in the magazine "Science." The detailed results now on the IUCN Red List show that the situation is particularly serious for tunas.

Five of the eight species of tuna are in the threatened or Near Threatened categories. These include: Southern Bluefin, Thunnus maccoyii, Critically Endangered; Atlantic Bluefin, T. thynnus, Endangered; Bigeye, T. obesus, Vulnerable; Yellowfin, T. albacares, Near Threatened; and Albacore, T. alalunga, Near Threatened.

This information is expected to inform governments as they make decisions regarding the future of these species, many of which are of high economic value. In January, a single giant bluefin tuna caught in Japanese waters fetched a record 32.49 million yen (US$396,000) at the world's largest wholesale fish market in Japan.

Amphibians form a vital role in ecosystems, are indicators of environmental health, and are literally "hopping pharmacies" being used in the search for new medicines. As one of the most threatened groups, amphibians are closely monitored by IUCN and 26 recently discovered amphibians have been added to the IUCN Red List.

The Blessed Poison Frog, Ranitomeya benedicta, is currently listed as Vulnerable and the Summers' Poison Frog, Ranitomeya summersi, is Endangered. Both are threatened by habitat loss and harvesting for the international pet trade.

"The IUCN Red List is critical as an indicator of the health of biodiversity, in identifying conservation needs and informing necessary changes in policy and legislation to drive conservation forward," says Jean-Christophe Vie, deputy director of IUCN's Global Species Programme.

Said Stuart, "Human beings are stewards of the Earth and we are responsible for protecting the species that share our environment."

"It is clear to me that society now has the capability to reverse species declines," said Professor Jonathan Baillie, director of conservation programs at Zoological Society of London. "Fundamentally, it is our values that need to change if we are to avert the looming extinction crisis."