99% of threatened species are at risk from human activities. The principle threats are habitat loss and degradation, invasive species, over-harvesting/hunting, pollution and disease and now climate change is increasingly recognized as a growing threat.
| HABITAT LOSS AND DEGRADATION |
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Habitat loss, fragmentation and degradation are the greatest threats to terrestrial wildlife. It affects 86% of th threatened birds and mammals and 88% of threatened amphibians.
| Isolated mountain lizards |
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Aran rock lizard (Iberolacerta aranica) Critically Endangered. Photo © Lasse Bergendorf |
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The very restricted ranges of several Spanish mountain lizards makes them very susceptible to habitat degradation and loss, particularly due to the development of alpine tourism, all-terrain vehicle use and overgrazing by cattle. The Critically Endangered Aran Rock lizard Iberolacerta aranica is confined to a mere 26 km2 in the Central Pyrenees and the closely related I. martinezricai to a single mountain top and nearby valley in central Spain. Even small scale changes could have a major impact on these populations, and as with all montane species, they may be threatened by future climate change.
| UNSUSTAINABLE USE, OVER-HARVESTING AND OVER-HUNTING |
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Over-exploitation is a major threat to mammals (33% of threatened species), birds (50% of threatened species) and amphibians (29%), and is the most serious threat to marine species.
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Atlantic sturgeon, one of the few unthreatened sturgeon species. Photo © Imene Meliane |
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Most of the 27 sturgeon species are threatened with extinction. Overfishing and poaching for caviar and meat, and habitat loss and degradation, due to pollution and damming rivers are the main causes. Caviar, the unfertilized sturgeon eggs, are a highly prized delicacy and wild caviar can sell for over $500 per kilo on the black market. Caviar stocks in the Black and Caspian seas have collapsed, causing the United States, the world's biggest consumer to ban Beluga sturgeon (Huso huso) caviar from the Caspian Sea. However, poaching will remain a serious threat until all major importers can ensure imports are from legal sources, such as licensed catches and caviar from sturgeon farms.
In early 2006, in response to the worsening situation, the U.N. Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) blocked caviar-producing countries from exporting their products until they can prove their sturgeon stocks are sustainable - all sturgeon species were listed in CITES in 1997 and export quotas were set in response. CITES has not yet authorised export quotas for 2006. IUCN SSC Sturgeon Specialist Group SSC Wildlife Trade Programme CITES
| Asian Yews threatened by exploitation for pharmaceutical industry |
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Asian Yew tree (Taxus chinensis var. mairei). Vulnerable. Photo © Rob Nicholson |
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Yew trees (Taxus spp.) are slow-growing, long-lived evergreen trees and shrubs. Over-exploited for taxanes (powerful chemical compounds which are widely used in the production of drugs for cancer treatment) found in their bark, Asian yews in particular have suffered drastic declines. Paclitaxel, the most important taxane, is exported as an extract; but the bark of 3,000 trees is needed to produce one kilo. 80% of the yew resources in China’s Yunnan Province, which used to be the country’s main area for yews, were destroyed in a three year period.
Widespread declines across Asia have resulted in five species being on the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), to control exports, and one species, Taxus fauna, is listed as Vulnerable on the IUCN Red List. However, illegal harvesting is still a serious problem.
Paclitaxel can be artificially synthesised, but not yet on a viable commercial scale. Some cultivation has been carried out, but only on a very small scale, as yews are such slow-growing species. Without urgent measures to only harvest trees in a sustainable way, the last populations of scattered yews in Asia will disappear rapidly and an important source for a vital drug will be lost. IUCN SSC Medicinal Plant Specialist GroupGlobal Tree Specialist GroupSSC Wildlife Trade Programme CITES
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