Discovery
The armadillo effect, times 1,000
By Massie Santos Ballon
Philippine Daily Inquirer
First Posted 00:41:00 10/11/2008
Filed Under: Science (general), People
MANILA, Philippines—The annual Ig Nobel Awards—that irreverent ceremony that honors scientific research that makes you laugh, then makes you think—was held at Harvard University last week.
And this year’s archeology Ig Nobel went to Brazilian researchers Astolfo G. Mello Araujo from the Universidade de São Paulo and José Carlos Marcelino of São Paulo’s Department of Historical Patrimony, who studied how a single species could change history.
To be more precise, the two men looked at how the armadillo’s tendency to burrow into the ground and throw dirt upward could disturb stratified layers being studied at archeological dig sites. As the layers could indicate various historical time points, disrupting them could lead to misinterpretations of the findings.
Mello Araujo and Marcelino’s work appeared in a 2003 issue of the journal Geoarcheology.
Impact global ecosystem
If a single armadillo wandering amid ruins can affect historical accuracy, imagine how losing as much as a quarter of the world’s mammalian species would impact the global ecosystem.
“We estimate that one in four species is threatened with extinction and that the population of one in two is declining,” wrote the authors of a new report published online in the journal Science earlier this week.
According to the five-year study completed by over 1,700 researchers in 130 countries, 1,141 of the 5,487 mammalian species on land and sea identified since 1,500 are facing extinction. (And yes, the calculation suggests that roughly one in five mammals are being threatened with extinction, but it’s possible the scientists are using data not presented in their report.)
The work was led by researchers from the International Union for Conservation of Nature and updates the findings in the 1996 IUCN report. The authors wrote that they chose to update the 1996 study because “the assessments are officially outdated for about 3,300 mammals never assessed since.”
Of the 1,141 species threatened, 76 have gone extinct, and two species are found only in captivity. It’s worth noting here that the Chinese dolphin known as the baiji is one of 29 species considered “possibly extinct,” though many scientists believe that the mammal, which has not been seen in the Yangtze River for over 50 years, is truly gone.
Endangered species
Another 188 species are “critically endangered,” while 448 species are “endangered” and 505 species are “vulnerable.” Of greatest concern though is that another 836 species are listed as “data deficient,” which means there isn’t enough information on them to determine whether these populations are stable or not.
The IUCN report found that a significant portion of the land mammals threatened live in South Asia and Southeast Asia. Nearly 80 percent of the primates found in Southeast Asia, for example, reportedly face extinction. One threat factor is habitat loss, which affects 40 percent of species worldwide.
Among marine mammals, 78 percent are threatened by what’s called “accidental mortality,” where they’re caught unintentionally by fishing nets or are hit by ships. The next biggest threat, affecting 60 percent of the undersea species, is pollution, ranging from physical debris and chemical contamination to harmful noise levels.
It’s not all bad news in the report though; 5 percent of the threatened species are marked as having stable populations, suggesting their status might someday be downgraded from serious.
Additionally, of the 5,487 species listed in the report, 19 percent of them have been discovered since 1992.
Wake-up call
Despite the grim news, the authors of the current IUCN report want to use the data as a wake-up call rather than a premature eulogy.
“More than simply reporting on the depressing status of the world’s mammals, these Red List data can and should be used to inform strategies for addressing this crisis,” they researchers concluded.
(E-mail the author at massie@massie.com.)
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