"Our knowledge about species and extinction rates remains very poor, and this has negative consequences for our environment and economy," says Simon Stuart, Chair of IUCN's Species Survival Commission. "By expanding the current IUCN Red List of Threatened Species™ to include up to approximately 160,000 well-chosen species, we will have a good barometer for informing decisions globally."

To date, almost 48,000 species have been assessed on the IUCN Red List, which costs about US$4 million each year. Most of this work is carried out by thousands of volunteers worldwide through the Species Survival Commission.

Globally, only 1.9 million species have been identified, though the estimated number of species is thought to be somewhere between 10 and 20 million. While the Red List contains assessments of all species of mammals, birds, amphibians, reef-building corals, freshwater crabs, cycads and conifers, the vast majority of the world's species are poorly represented, including many plants, invertebrates, reptiles, fishes and fungi.

"The more we learn about indicator species (which can provide information on the quality of the environment around them), the more we know about the status of the living environment that sustains us all," says Edward O. Wilson, a prominent biologist at the Museum of Comparative Zoology at Harvard University. "Threatened species, in particular, need to be targeted to enable better conservation and policy decisions."

"We urgently need to ramp up current efforts to catalogue a far more representative selection of our vast biodiversity, while we still can, and we should focus first and foremost on those areas of highest extinction risk," says Russell Mittermeier, President of Conservation International and Chair of IUCN/SSC Primate Specialist Group. "Such information will also help governments and communities to design appropriate responses to climate change and to other pressing conservation challenges."

"Another important challenge is to strengthen scientific capacity for performing Red List assessments in biodiversity-rich areas. The developing world is home to most of the earth's species, but human resources for monitoring this natural wealth are seriously lacking," says Jon Paul Rodríguez, an ecologist at the Venezuelan Institute for Scientific Investigation and the Venezuelan NGO Provita, who serves as Deputy Chair of IUCN's Species Survival Commission.

"The fact that we will not achieve the 2010 target to halt the loss of biodiversity is disheartening," says Jeff McNeely, Senior Science Advisor, IUCN. "But complaining will not help nearly as much as a redoubled effort to conserve what remains of our planet's living wealth. The Barometer of Life offers us an effective tool for measuring our progress towards saving life on earth."

The authors of the Science article, "The Barometer of Life," are: Simon Stuart, Chair of IUCN's Species Survival Commission (SSC), Bath, UK; Edward O. Wilson, Museum of Comparative Zoology, Harvard University, Cambridge, MA, USA; Jeffrey A. McNeely, Senior Science Advisor, IUCN, Gland, Switzerland; Russell A. Mittermeier, President of Conservation International, Arlington, VA, USA, and Chair of the IUCN SSC Primate Specialist Group; Jon Paul Rodriguez, Centro de Ecología, Instituto Venezolano de Investigaciones Cientificas, Caracas, Venezuela, and SSC Deputy Chair.

About the IUCN Red List of Threatened Species™

The IUCN Red List of Threatened Species™ (or the IUCN Red List) is the world's most comprehensive information source on the global conservation status of plant and animal species. It is based on an objective system for assessing the risk of extinction of a species should no conservation action be taken.

Species are assigned to one of eight categories of threat based on whether they meet criteria linked to population trend, population size and structure and geographic range. Species listed as Critically Endangered, Endangered or Vulnerable are collectively described as 'Threatened'.

The IUCN Red List is not just a register of names and associated threat categories. It is a rich compendium of information on the threats to the species, their ecological requirements, where they live, and information on conservation actions that can be used to reduce or prevent extinctions. www.iucnredlist.org

Note: If no author is given, the source is cited instead.

• Nature
• New Species

• Ecology
• Environmental Policy

• Land Management
• Environmental Policies

• Conservation status
• Giant clam
• Canada Lynx
• Columbian White-tailed Deer
• Caribbean Monk Seal
• Wild Horse