Category Archives: Extinction

EXTINCTION: White-nose syndrome threatens bats with extinction

Posted on
1

Image: Little brown bat with white-nose syndrome

A fungus is threatening to wipe out certain species of North American bats. According to Mylea Bayless of Bat Conservation International, “‘We’re watching a potential extinction event on the order of what we experienced with bison and passenger pigeons for this group of mammals.‘” The problem is severe, because “U.S. Fish and Wildlife Service biologists and
[their] partners estimate that at least 5.7 million to 6.7 million bats have now died from white-nose syndrome.” Apparently, the fungus kills the bats by aggravating colonies, which should be hibernating, during the winter months, and the aggravation causes these colonies to burn up too much energy. Bats can’t normally feed during the cold winter months, so they perish after burning up all their energy stores.

Bats provide an important ecosystem service by consuming insects “that feed on agricultural crops and forests. For example, “a reproductive female consumes her weight in bugs each night[, and] in a single summer, a colony of 150 brown bats can eat enough adult cucumber beetles to prevent the laying of eggs that result in 33 million rootworm larvae … .” The fungus, which causes the disease, Geomyces destructans, “originated in Europe, where some bats acquired immunity, and was somehow transmitted to bats in North America which lack any immunity to the disease[, so] … some officials … argue that humans may also transmit WNS from infected sites to clean sites, probably on clothing and equipment.” More via Scientific American:

[E]xperiments show that bats are quite effective at spreading the destructive fungal disease to their neighbors. “Bats are very good agents of transmission of the disease,” Chaturvedi says. And that—plus the European analysis—may suggest that G. destructans is an invasive species, according to Blehert, which possibly traveled to the U.S. on a European who visited a public cavern in New York State. WNS was first observed in a wild cave connected to that commercial cave complex near Albany, N.Y. Chaturvedi’s work has shown that G. destructans in North America is genetically similar wherever it is found.

Video: Economic effects of White Nose Syndrome

Video: Declining Bat Population (from September 7, 2009)

On the Net:

  1. Bat Conservation International
  2. It’s Official: Fungus Causes Bat-Killing White-Nose Syndrome
  3. Nearly 7 million bats may have died from white-nose fungus, officials say
  4. U.S. Fish & Wildlife Service: White-Nose Syndrome
  5. North American bat death toll exceeds 5.5 million from white-nose syndrome

EXTINCTION: Rhinos face bleak future

Posted on
1

These images, via the Daily Mail and photographer Michael Raimondo, illustrate the extremes that conservationists must take in order to save wildlife from extinction. According to the Daily Mail, these “images show exactly how conservationists used a military helicopter to carry the herd of 1,400-kilo rhinos to their new home, away from poachers.”

According to the IUCN Red List of Threatened Species, several species of rhinoceros continue to hurdle towards extinction as poaching and habitat degradation, loss, and fragmentation continue to expand. The group also warns that “a quarter of all mammal species assessed are at risk of extinction.” The story of extinction is a story of human expansion. In order to stop extinction, governments must seriously implement policies that address overconsumption, alleviate imprudent development, and consider conservation. Without prudent conservation policies that work, more remarkable species will continue to go extinct. More via the AFP:

All told, a quarter of all mammal species assessed are at risk of extinction, the International Union for the Conservation of Nature (IUCN), which compiles the list, said on Thursday.

About a third of the 61,900 species now catalogued by the IUCN are classified as “vulnerable,” “endangered,” “critically endangered,” or extinct, with some groups, such as amphibians and reptiles, in particularly rapid decline.

Rhinoceros have been hit especially hard in recent years. Their fearsome horns — prized for dagger handles in the Middle East and traditional medicine in east Asia — can fetch hundreds of thousands of dollars on the black market.

The new assessment shows that a subspecies of the western black rhino (Diceros bicornis longipes) native to western Africa is now extinct, joining a long list of creatures — from the Tasmanian tiger to the Arabian gazelle — that no longer stride the planet.

Central Africa’s northern white rhino (Ceratotherium simum cottoni) is listed as “possibly extinct in the wild”, while the Javan rhino (Rhinoceros sondaicus) is making a last stand after the remaining specimen of its Vietnamese counterpart was killed by poachers last year.

“Human beings are stewards of the earth and we are responsible for protecting the species that share our environment,” Simon Stuart, head of the IUCN Species Survival Commission, said in a statement.

“In the case of both the western black and the northern white rhinos the situation could have had very different results if suggested conservation measures had been implemented.”

There were a few slivers of good news showing that species can be prevented from slipping into oblivion.

The southern white rhino subspecies (Ceratotherium simum simum) is back from the brink, its numbers up from 100 at the end of the 19th century to some 20,000 today.

Certainly, zoological parks will continue to play an important role in preventing species from vanishing from the Earth forever. Via McClatchy:

The eastern black rhinoceros is a critically endangered species, but the Kansas City Zoo just keeps churning them out.

Or, rather, it is Luyisa who has been doing the work, having just produced her third healthy calf in 10 years.

“Everybody was very thrilled about it,” said General Curator Liz Harmon, referring to the reaction of the zoo world and conservation experts to this birth, which occurred Oct. 18. “When it was born — and it was a girl — everybody was ecstatic.”

First, any birth in a species that only has a few hundred left in the wild is a good thing. Second, there are more males than females in the captive population, so girls are celebrated. Third, the father in this case had never sired a calf before, so his genes are not overrepresented.

And fourth, Luyisa, the mom, was born in the wild, so her genes are a welcome infusion into the captive gene pool.

The latest addition in Kansas City has been named Layla. The zoo has not made a splash about her because she won’t be on public display until the African section of the animal park reopens April 1, but The Kansas City Star got a sneak peak on Friday.

The Kansas City Zoo went to Africa to acquire Luyisa in 1997 in a trip chronicled by The Star. At the same time, the Cleveland Metroparks Zoo brought back a female of its own. She produced her fourth calf in August this year.

As a bonus, all seven offspring of those two animals have been female.

“It was good trip,” Harmon said of that 1997 expedition. “It helped the population a lot.”

EXTINCT SPECIES: Study determines that Tasmanian tiger’s jaws were too weak to kill sheep

Posted on
1

Image of a shot thylacine and thylacine cubs via Wikipedia

Scientists, with the help of computer software, recently discovered that the now-extinct Tasmanian tiger, or thylacine, wasn’t the sheep-killer that ranchers made them out to be. Via the BBC:

This digital “crash test” revealed that thylacine’s jaws were simply too weak to have brought down an adult sheep.

“If a large carnivore – like a big cat for example – wants to take down a big prey item, it has to clamp down on its throat and suffocate it,” said Dr Wroe.

“A thylacine wouldn’t have been capable of this.”

The digital “crash test” revealed the weak points in thylacine’s jaws
Dr Wroe also explained that thylacine’s teeth were “built for slicing” rather than for crushing bone.

Comparing its skull performance with closely related, living species with known diets, the scientists were able to predict the likely body size of its prey.

“It probably fed on small animals, such as possums,” said Dr Wroe. “And its limited diet would have made it more vulnerable to extinction.”

.       .       .

“The terrible loss of the thylacine signifies unjustified, negligent destruction of our native flora and fauna. It is a cautionary reminder of what we have lost, and that without urgent intervention other species will suffer the same fate.”

CONSERVATION: Scientists introduce non-native species in an attempt to save island ecosystem

Posted on
Reply

Image via Joachim S. Müller on Flickr.

Scientists are “re-wilding islands and even continents” in order to remedy sickened or damaged ecosystems. In one example of re-wilding ecosystems, scientists introduced a species of giant tortoise, from Aldabra Atoll in the Seychelles, to take on the ecological role that was played by a similar species of giant tortoise that went extinct on Ile aux Aigrettes, which is an island associated with Mauritius. More via Scientific America:

In 1965 the largely denuded 25 hectares of [Ile aux Aigrettes] were declared a nature reserve. But even in the absence of logging, the slow-growing ebony forests failed to thrive. Why? Because they had lost the animals that ate their fruit and dispersed their seeds. So in 2000 scientists relocated four giant tortoises from the nearby Aldabra atoll in the Seychelles, and by 2009 a total of 19 such introduced tortoises roamed the island, eating the large fruits and leaving behind more than 500 dense patches of seedlings. The team reported its results in April in the journal Current Biology.

For this tiny island, at least, rewilding appears to have worked. And that holds out hope for other restoration ecology projects in the midst of the sixth mass extinction in the earth’s history. In Europe conservationists have received €3.1 million to begin bringing bison, bovines and horses back to “abandoned” agricultural lands in places such as western Spain or the Carpathian Mountains. Ecologists have proposed repopulating parts of the U.S. with elephants, which would replace extinct mastodons. The Dutch, for their part, have already built what amounts to a Pleistocene park at Oostvaardersplassen, adding Konik horses and Heck cattle to replace extinct wild horses and cattle.

Of course, humans have a mixed track record when it comes to interfering in natural ecological systems—the introduction of the cane toad to Australia to manage other pests has resulted in a frog march of havoc across the continent. “There are no guarantees when trying to manipulate nature,” notes ecologist Mark A. Davis of Macalester College in Minnesota. Others argue that humans should fix what they have broken. “There is no place on this planet that humans have not interfered with, and it is time for us to become actively involved in engineering solutions,” says marine biologist Ove Hoegh-Guldberg of the University of Queensland in Australia. “There are no other options except extinction at this point.”

Continue reading this article at Scientific America.

IVORY-BILLED WOODPECKER: More evidence suggests that the ivory-billed woodpecker isn’t extinct

Posted on
4

The images, by Dr. Michael Collins, are purported to be of ivory-billed woodpeckers living in Louisiana. Dr. Michael Collins’s images are via Wildlife Extra.

An amateur birdwatcher claims that photographs and audio recordings, which he took, are of ivory-billed woodpeckers living around the Pearl River area of Louisiana. Apparently, his evidence has been dismissed by the professional ornithological community. Nonetheless, he defends the authenticity of his data and is publishing his work in the Journal of the Acoustical Society of America. Via LiveScience.com:

[Michael] Collins is an outsider to the ornithology community—he’s just a hobbyist bird-watcher—and few insiders take his work seriously. His evidence has been rejected by a string of ornithology journals – often, he says, without explanation.

And so he has turned to acoustics scientists to confirm his recordings. This month he will finally publish what he believes is solid evidence that ivory-billed woodpeckers live at Pearl River in the Journal of the Acoustical Society of America.

Collins, a researcher at the Naval Research Laboratory-Stennis Space Center in Mississippi, first started searching for the bird when a team of Cornell ornithologists captured putative footage of a specimen in Arkansas in 2005. That possible sighting, the first well-documented (though not definitive) human encounter since about 1940, made it onto the cover of Science Magazine. The birds were said to have lived at Pearl River in the past, so when Collins heard that they might still exist as a species, he decided to look for them there.

.       .       .

The audio recordings, which he obtained in conjunction with the videos, also smack of the Lord God bird, which makes very distinct double knocks when pecking, and makes vocalizations somewhat like a blue jay’s and nothing like a pileated woodpecker’s. Collins used his mathematics expertise to construct sophisticated acoustical models of the bird’s vocalizations. The audio and video evidence combined, he says, give firm support to his claim that ivory-billed woodpeckers live at Pearl River.

.       .       .

“Professional jealousy is a huge problem in the field of ornithology,” Collins said. “There are groups who have received a lot of funding to obtain conclusive data on these birds and haven’t managed to do so, and I’ve done it independently.” One such group, he said, is the Cornell Lab of Ornithology, the country’s leading center of ornithology research and the group who may have sighted the elusive woodpecker in 2005.

.       .       .

The Cornell group, which Collins accuses of having exerted its influence to keep his work out of ornithology journals, commented briefly on his new acoustics paper.  ”Although we believe the evidence presented is inconclusive, we applaud Collins’s continued efforts to locate and document possible ivory-billed woodpeckers and to publish his findings for all to evaluate,” Kenneth Rosenberg, director of conservation science in the group, said.

You can read the rest of this article at LiveScience.com. More on Collins’s claims can be found at Wildlife Extra.