The Population Decline and Extinction of Darwin’s Frogs
Darwin’s Frogs are two species of frogs of the family Rhinodermatidae: Rhinoderma darwinii (also called the Southern Darwin’s frog) and Rhinoderma rufum (also known as Chile Darwin’s frog or Northern Darwin’s frog); the first native to Chile and Argentina and the second endemic to central Chile. Both frogs are named after Charles Darwin who had previously discovered it in Chile during his world voyage on the HMS Beagle.
A peculiarity of these frogs is that species are mouth-brooding and tadpoles develop inside the male vocal sac.
Rhinoderma darwinii is classified since 2004 as “Vulnerable" on the IUCN Red List and Rhinoderma rufum is listed as “Critically Endangered" since 2010. The main threats to these species are drought, pine forestry and clear-cutting of forest for R. darwinii, and he destruction of the native vegetation for R. rufum.
However, a study published in June 2013, developed by researchers at the University Andres Bello (Chile), University College London, Zoological Society of London and the University of Chile, which included extensive surveys carried out throughout the historical ranges of both species from 2008 to 2012, provide evidence that R. rufum is extinct and indicate that R. darwinii has declined to a much greater degree than previously recognized.
According with this study, the last sighting of R. rufum based on museum archives and the scientific literature, was in 1980. Although Rhinoderma darwini can still be found across a large part of its historical range, remaining populations are small and severely fragmented. Conservation efforts for this frog should be stepped up and the species re-classified as Endangered.
In addition, a later study (November, 2013) indicates that the amphibian disease chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis is also a factor in the decline of populations of Rhinoderma species.
Research groups around the world are attempting to resurrect extinct species.
by Abby Olena
The only ever successful de-extinction was the birth of a baby bucardo (Capra pyrenaica pyrenaica)—a type of ibex specifically adapted to the Pyrenees Mountains in Europe—in 2003, though the young animal died soon after birth because its lungs did not function properly, according to BBC News. The clone was generated using frozen cells harvested in 1999 from the last bucardo, an old female that died in 2000. Now, the BBC reports that the Centre for Research and Food Technology of Aragon (CITA) in Zaragoza, Spain, will begin a new project to examine the burcado frozen cells to determine whether de-extinction efforts ought to be resurrected.
“At this moment, we are not initiating a bucardo recovery plan,” Alberto Fernandez-Arias, the head of the Service of Hunting, Fishing and Wetlands in the Aragon government, told the BBC. “We only want to know if Celia’s cells are still alive after having been maintained frozen during 14 years in liquid nitrogen.” Fernandez-Arias told the story of the 2003 bucardo de-extinction experiment in one of 25 talks at the TEDxDeExtinction meeting held this spring (March 15) in Washington, D.C…
Researchers in Spain to attempt to clone extinct mountain goat
(Phys.org) — A team of researchers in Spain, with the Centre for Research and Food Technology of Aragon, has signed an agreement with the Aragon Hunting Federation (which they announced to the press) to begin testing the possibility of cloning a mountain goat that went extinct back in 2000.
The bucardo (Capra pyrenaica pyrenaica) was a sub-species of mountain ibex that lived in the Pyrenees—its numbers had been dwindling for years due to a number of factors, including a changing environment and hunting by humans. The last known survivor was a goat named Celia—she was killed by a tree falling on her—but not before researchers took tissue samples and froze them in liquid nitrogen. The hope was that as technology improved, eventually, cells from the samples could be used to clone new goats and thus resurrect the species…
5 Costa Rican frogs that came back from suspected extinction and 1 that didn’t
by Lindsay Fendt
After mass declines in populations in Costa Rica, scientists now have some hope for many of these tiny amphibians.
Climate change, habitat destruction, the illegal pet trade and the spread of a severe and incurable fungus have been killing off amphibian species in droves in Costa Rica since the late 1980s. Many once-abundant species are now extinct, but according to a study released this month in the journal Amphibia-Reptilia, there may be hope.
The study discusses the rediscovery of the orange or yellow and black harlequin frog species, known as the clown frog or Halloween frog, which was declared extinct – then rediscovered – in Costa Rica twice, most recently in 2008.
The species is among several types of harlequin frogs that have re-emerged in Costa Rica since 2005 and scientists believe this could be the beginning of a slew of amphibian rediscoveries following massive population declines…
(read more: Tico Times)
photos: Matt McGee; Smithsonian Tropical Research Institute; Robert Pushendorf; University of Kansas;
Extinction. The end of a species; no coming back. Many conservation efforts strive to save species from this fate, and a species’ risk of extinction can also be a major factor in determining its listing as endangered.
A recent study published in Nature suggests, though, that we may want to pay a bit more attention to something called “functional extinction” — the point at which a species has too few members to continue filling its ecological role, even though it may still have a way to go until traditional “numerical extinction.”
Researchers at Linköping University in Sweden ran a number of analytical models to determine how often and in what circumstances functional extinctions occur. They found that larger animals are more likely to become functionally extinct, often driving smaller animals in a food web to numerical distinction. What’s more, this functional extinction can occur following a population decline of as little as 30 percent, meaning that a species only has to lose a third of its members before other plants and animals in the same food web may start to disappear…
The North Island Takahē or Mōho, is an extinct rail that was found in the North Island of New Zealand. This flightless species is known from subfossils from a number of archeological sites and from one possible 1894 record (Phillipps, 1959). It appeared to have been even larger than the South Island Takahē and, if it did survive until the 1890s, would have been the largest rail in historic times. The decline of the species has generally been attributed to the increasing incursion of forest into the alpine grasslands through the Holocene, although hunting by the Māori also played a major role.
Traditionally the North Island Takahē was considered conspecific with the threatened South Island Takahe P. hochstetteri. Trewick (1996) presented evidence that the two taxa were independently derived from flying ancestors, so proved to be separate species.
Phylum : Chordata Class : Aves Order : Strigiformes Family : Strigidae Genus : Ornimegalonyx Species : O. oteroi, O. minor, O. gigas, O. acevedoi
Late Pleistocene (10 000 years)
1,1 m high and 9 kg
The sheer size of the first remains along with their proportions initially led to the identification that Ornimegalonyx was a phorusrhacid ‘terror bird’ similar to the smaller members of that group such as Psilopterus. This classification continued until 1961 when Pierce Brodkorb correctly identified the remains as that of a large ground dwelling owl (two years later Brodkorb would identify Titanis, the first phorusrhacid from North America).
Ornimegalonyx is thought to have used its long and powerful legs to chase after prey rather than flying. This behaviour would see Ornimegalonyx hunting for small to medium sized mammals, particularly large rodents that are common to Central American Islands. Ornimegalonyx would likely use its powerful feet and claws to strike out at its prey and cause fatal injuries to the spine, neck and face. These areas are often targeted for attack by owls that fly, the idea being to incapacitate their prey so that it cannot escape should the first attack not prove fatal.
Ornimegalonyx may not have limited itself to just running after its prey, but may have also used what is termed a pouncing strategy. This hunting behaviour would involve Ornimegalonyx taking up a position above the forest floor and waiting for prey to approach beneath. Ornimegalonyx could just hop off its perch and drop down, perhaps holding out its wings to both slow down and steer its descent for a precision strike on its unsuspecting prey.
Even though the wings are greatly reduced in size, Ornimegalonyx may have still been capable of limited bursts of flight. The keel of the breast bone while reduced would still allow for some development of the flight muscles that in other birds allowed for powered flight. Ornimegalonyx may have used its long legs to spring itself up into the air and then flap its wings to slow its descent and extend the range of the jump. This way Ornimegalonyx may have been able to take up positions off the floor where it could rest as well as hunt for food.
Florida declares two butterfly species extinct as pollinator crisis worsens
by Alexander Holmgren
Conservationist’s faced a crushing blow last month as two butterfly species native to Florida were declared extinct.
“Occasionally, these types of butterflies disappear for long periods of time but are rediscovered in another location,” said Larry Williams, U.S. Fish and Wildlife state supervisor for ecological services. We think it’s apparent now these two species are extinct.”
Neither species has been seen in any environment for at least nine years, the latter of the two not being seen since 2000. This calamity is only made worse by the fact that so much could have been done in order to save these creatures. The first species, the Zestos skipper butterfly (Epargyreus zestos oberon), had strong bodies with large black eyes and large wings that were adorned with spots that looked like eyes. While the Zestos skipper was visibly declining in its environment, the subspecies was denied access to the U.S.’s Endangered Species Act (ESA) because of the confusion between it and other skipper species in the Bahamas. In the end, what was thought to be a bountiful reserve in the Bahamas proved to be a completely different species. By the time the mistake was realized it proved too late.
The Rockland grass skipper butterfly (Hesperia meskei pinocayo), an amber golden insect with club like antenna and black eyes, was similarly thought to be making a comeback as the species that had not been seen since the 80’s was spotted back in 2000. But is now believed extinct…
Lipotes vexillifer is probably the most endangered cetacean, and may already be extinct. It lives only in the Yangtze River in China, where they feed on freshwater fish. It lives in small groups of three or four dolphins, although group sizes can reach up to sixteen individuals. It has been sighted swimming with finless porpoises (Neophocaena phocaenoides), which also live in the Yangtze River.
The Yangtze River is one of the busiest stretches of water in the world, which has put much pressure on L. vexillifer. A recent threat is the use of electricity for fishing, which has caused 40% of deaths of this species in recent years. Some also become caught in fishing equipment, and the entire river ecosystem is poisoned by pesticides and pollution.
L. vexillifer has been a protected species since 1975, but this did not help stop the decline in numbers. Five Baiji Semi-Natural Reserves were created in 1992 and it was planned that all wild individuals would be relocated to these areas. Unfortunately, catching the dolphins was extremely difficult, and those that were captured only survived for a few months. There have been no sightings since 2004, and this species may already be extinct.
An Australian bushman and naturalist claims to have captured video footage of the night parrot, a bird not seen alive for more than a century.
John Young, who describes himself as a wildlife detective, showed the footage and a number of still photos of the bird to a packed room of enthusiasts and media at the Queensland Museum on Wednesday.
The desert-dwelling night parrot, Pezoporus occidentalis, has never been photographed and the only evidence of its continued existence has been two dead birds found in 1990 and 2006.Wildlife authorities and birders responded to the sighting with excitement, saying the evidence supporting Young’s claim was overwhelming.
Dr Steve Murphy, senior ecologist at the Anangu Pitjantjatjara Yankunytjatjara Land Management Unit in South Australia, told ABC News that the finding was a certainty…
(1) The last documented sighting of China’s baiji dolphin, or Yangtze River dolphin, was in 2002, and while the species is listed as critically endangered, scientists say it may already be extinct. In 2006, scientists from the Baiji Foundation traveled up the Yangtze River for more than 2,000 miles equipped with optical instruments and underwater microphones, but were unable to detect any surviving dolphins. The foundation published a report on the expedition and declared the animal functionally extinct, meaning too few potential breeding pairs remained to ensure the species’ survival.
(2) The golden toad, which is sometimes referred to as the Monteverde toad or the orange toad, was a species that lived only in the Monteverde Cloud Forest Biological Reserve in Costa Rica. It was once a common species, but no specimen has been seen since 1989. The toad’s breeding sites were well-known and closely watched — in 1988, only eight males and two females could be found, and in 1989, only a single male could be located. Extensive searches for the golden toad since then have failed to locate another specimen, and the species was declared extinct in August 2007. The amphibian disease chytridiomycosis, airborne pollution and global warming probably contributed to the species’ demise.
(3) Hawaiian Crow. This native Hawaiian bird was declared “extinct in the wild” in 2002 when the last two known wild individuals disappeared. Some birds remain in captivity, and between 1993 and 1999, more than 40 birds were hatched in a captive breeding program. The birds were released into a lightly managed habitat and closely monitored, but releases were abandoned in 1999 because of increasing mortality. A reintroduction plan is being developed, but about 75 Hawaiian crows would be needed for the plan to work. The reasons for the bird’s extinction is not fully understood, but researchers speculate that an introduced disease, such as avian malaria, might have played a significant role in the species’ decline.
(4) The Pyrenean ibex is one of two extinct subspecies of the Spanish ibex. The species was once numerous and roamed across France and Spain, but by the early 1900s its numbers had fallen to fewer than 100. The last Pyrenean ibex, a female nicknamed Celia, was found dead in northern Spain on Jan. 6, 2000, killed by a falling tree. Scientists took skin cells from the animal’s ear and preserved them in liquid nitrogen, and in 2009 an ibex was cloned, making it the first species to become “unextinct.” However, the clone died just seven minutes later due to lung defects.
(5) The rarest of the black rhino subspecies, the West African black rhinoceros is currently recognized as “critically endangered,” but researchers fear it may be extinct. The species was once widespread in central Africa, but the population has been in decline due to poaching. By 1980, the population was in the hundreds, and by 2000 only an estimated 10 rhinos remained. A survey of the animal’s last remaining habitat in northern Cameroon failed to find any of the rhinos, but search efforts continue. No West African black rhinos are known to be held in captivity.
(6) Although 71 Spix’s macaws exist in captivity, the last known bird in the wild disappeared in 2000 and no others are known to remain. The species is currently listed as “critically endangered” instead of “extinct in the wild” because not all areas of potential habitat have been thoroughly surveyed. The bird is native to northern Brazil and in 1987 the three known remaining birds were captured for trade. However, a single male bird was discovered in 1990 and paired with a female bird in captivity, but seven weeks after the female’s release, she collided with a power line and died.
Rare newts in Prospect Park Zoo may be extinct in the wild
by Phyllis Sena
The Prospect Park Zoo in Brooklyn, New York City, is now home to five critically endangered Kaiser’s spotted newts (Neurergus kaiseri).These black, white, and orange amphibians are found only in a five-square-mile region in Iran. Severe habitat loss and the illegal trade of these rare amphibians has driven the species to possibly be extinct in the wild, and they are officially ranked as critically endangered by the IUCN. The Kaiser’s spotted newts live in the Animals in Art exhibit at the WCS Prospect Park Zoo, which is also home to a Amphibian Crisis exhibit that highlights the serious challenges amphibians face around the world.
PASSENGER pigeons once formed flocks so vast that they would darken the sky for days as they flew past. In the 19th century there were some 5 billion individual birds in North America, more than any other wild bird species in the world.
US environmentalist Stewart Brand has an ambitious plan to “de-extinctify” passenger pigeons – bring them back to life by identifying and then splicing the relevant genes into a relative, the band-tailed pigeon. The technical challenges are formidable, and even if it works, the species might still not be viable in the wild. Nor is it agreed that reintroducing extinct animals into the modern world is a good idea. Brand waves this objection away, saying that the pigeon’s old habitat is intact, adding: “In the rare case of unwelcome ecological disruption, we know the vulnerabilities of the formerly extinct animals, so we know exactly how to reduce their numbers or eliminate them again.”