The Australian marsupial saw a rapid fall from "least concern" to "endangered" status after an infectious facial cancer wiped out 60 percent of its population. (See "Tasmanian Devils Named Endangered Species" [May 21, 2008].)
Also, the deadly chytrid fungus continues to threaten amphibians, which have hit a new low. (See "Deadly Frog Fungus Spreads in Virus-Like Waves" [April 1, 2008].)
Thirty-two percent of all amphibians are now threatened or extinct, said Simon Stuart, chair of IUCN's Biodiversity Assessments Sub-committee. For example, Holdridge's toad of Costa Rica, previously listed as critically endangered, has now been deemed extinct.
But most species are plummeting because of habitat destruction, "the most significant threat to [land] species," Stuart said.
For instance, the newly listed, "critically endangered" Rameshwaram parachute spider—a tarantula species found only on the Indian island of Rameshwaram—has lost nearly all its habitat to plantation development.
Likewise, Asia's fishing cat, now labeled endangered, has suffered from the draining of its wetland territory for farms and settlements.
There are a few bright spots in the findings.
The La Palma giant lizard—presumed extinct for the past 500 years—has been rediscovered on La Palma island in the Canary Islands—"very good news," according to Stuart.
Overall, 5 percent of threatened mammals show signs of improvement in the wild, the report found.
These two successes point to the potential of reintroduction programs to save species, Jan Schipper, of IUCN-Conservation International Global Mammal Assessment, told National Geographic News.
But reintroduction is not the most cost-effective strategy, Schipper added. Efforts should be made to stave off species extinction before the threat to a species reaches a critical level, he said.
"Dow Jones Index" for Species
As part of that effort to spot trouble early, IUCN and the Zoological Society of London have launched the sampled Red List Index, "which could be considered the Dow Jones Index for biodiversity," according to a press statement.
As in the Dow Jones approach to tracking stock market trends, a few individual "stocks" (in this case, species) are tracked as indicators of the overall health of the "market" (in this case, an overall taxon, or group of species—for example, reptiles).
The approach is also similar to election polling, in which the responses of a random sample are used to gauge trends.
"We need to know if things are getting better or getting worse. And when we have interventions, are they successful?" Jonathan Baillie, conservation-programs director for the zoological society, told National Geographic News.
Baillie and colleagues have already assessed reptiles and some invertebrate groups.
After adding the "Dow Jones" reptile data to the new Red List assessments of mammals and amphibians, he predicts that 24 percent of the world's land-dwelling vertebrates (animals with spines) may be under threat.
This initial use of the Dow Jones approach, "indicates that biodiversity is in peril," he said.
"And we don't see any [U.S.] $700-billion bailout plan on the horizon."
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