Lizard Hunting Styles Impact Ability To Walk, Run

Source:

http://www.sciencedaily.com/releases/2008/04/080421145204.htm

ScienceDaily (Apr. 26, 2008) — The technique lizards use to grab their grub influences how they move, according to researchers at Ohio University.

A research team led by doctoral student Eric McElroy tracked 18 different species of lizards as they walked or ran in order to understand how their foraging styles impact their biomechanics.
Lizards use two basic foraging techniques. In the first approach, aptly dubbed sit-and-wait, lizards spend most of their time perched in one location waiting for their prey to pass. Then, with a quick burst of speed, they run after their prey, snatching it up with their tongues.
In the other form of foraging, known as wide or active foraging, lizards move constantly but very slowly in their environment, using their chemosensory system to stalk their prey, according to the research team, which included McElroy’s adviser Stephen Reilly, professor of biological sciences, and undergraduate honors thesis student Kristin Hickey.
Although wide foraging evolved from the sit-and-wait technique, these two styles are almost opposites. Some wide foragers are on the move about 80 percent of the time while sit-and-wait foragers may move only about 10 percent of the time, said Reilly, co-author of a recent book on the topic, Lizard Ecology, published by the Cambridge University Press.
While all lizards have the ability to run, a predatory defense mechanism, the study found that sit-and-wait lizards won’t walk. Lizards that use the sit-and-wait method of foraging use running mechanics even when moving at slower speeds.
Wide foragers, however, evolved a walking gait and mechanics. They must move at slower speeds in order to use their advanced chemosensory system to locate their prey.
Foraging and locomotion are so closely linked, in fact, that three groups of wide foragers that had reverted to using the sit-and-wait technique actually lost the ability to walk, the researchers reported.
“The most interesting aspect of this research is that it demonstrates a clear link between animal behavior and functional morphology. It’s quite amazing and surprising that the behavioral diversity that everyone knows about and is inspired by is grounded in form, function and physiology,” McElroy said.
The researchers used a race track with a built-in force plate to record the forces generated by the lizards and a high-speed video camera to record each critter moving at various speeds. The scientists collected data from the force plate and analyzed the video to determine whether the lizard was using running or walking mechanics.
The study used a large, representative sample of lizards made up of 18 different species, such as skinks, iguanas and monitor lizards. This extensive study uses one of the largest data sets for center of mass mechanics, McElroy said, and is one of the few that focuses on reptiles instead of mammals.
“Everybody works with people, dogs or horses. But they’re all freaks,” Reilly said. “They’ve gone erect, they have extra joints. They are the kings of bouncing vaulting and running fast. We are working on the sprawlers.”
The study, funded by the National Science Foundation, was featured in the April 1 edition of the Journal of Experimental Biology.
Adapted from materials provided by Ohio University.

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Arctic Marine Mammals On Thin Ice

Source:

http://www.sciencedaily.com/releases/2008/04/080423154558.htm

ScienceDaily (Apr. 26, 2008) — The loss of sea ice due to climate change could spell disaster for polar bears and other Arctic marine mammals. Sea ice is the common habitat feature uniting these unique and diverse Arctic inhabitants. Sea ice serves as a platform for resting and reproduction, influences the distribution of food sources, and provides a refuge from predators.

The loss of sea ice poses a particularly severe threat to Arctic species, such as the hooded seal, whose natural history is closely tied to, and depends on, sea ice.

The Arctic undergoes dramatic seasonal transformation. Arctic marine mammals appear to be well adapted to the extremes and variability of this environment, having survived past periods of extended warming and cooling.
"However, the rate and scale of current climate change are expected to distinguish current circumstances from those of the past several millennia. These new conditions present unique challenges to the well-being of Arctic marine mammals," says Sue Moore (NOAA/Alaska Fisheries Science Center).
The April Special Issue of Ecological Applications examines such potential effects, puts them in historical context, and describes possible conservation measures to mitigate them. The assessment reflects the latest thinking of experts representing multiple scientific disciplines.
Climate change will pose a variety of threats to marine mammals. For some, such as polar bears, it is likely to reduce the availability of their prey, requiring them to seek alternate food. Authors Bodil Bluhm and Rolf Gradinger (University of Alaska, Fairbanks) note that while some Arctic marine mammal species may be capable of adjusting to changing food availability, others may be handicapped by their very specific food requirements and hunting techniques. Species such as the walrus and polar bear fall under this category, while the beluga whale and bearded seal are among those who are more opportunistic in their eating habits and therefore potentially less vulnerable, at least in this regard.
Using a quantitative index of species sensitivity to climate change, Kristin Laidre (University of Washington) and colleagues found that the most sensitive Arctic marine mammals appear to be the hooded seal, polar bear, and the narwhal, primarily due to their reliance on sea ice and specialized feeding.
Shifts in the prey base of Arctic marine mammals would likely lead to changes in body condition and potentially affect the immune system of marine mammals, according to Kathy Burek (Alaska Veterinary Pathology Services). She and fellow researchers point out that climate change may alter pathogen transmission and exposure to infectious diseases, possibly lowering the health of marine mammals and, in the worst case, their survival. Changing environmental conditions, including more frequent bouts of severe weather and rising air and water temperatures, also could impact the health of Arctic marine mammals.
The effects of climate change will be compounded by a host of secondary factors. The loss of ice will open the Arctic to new levels of shipping, oil and gas exploration and drilling, fishing, hunting, tourism, and coastal development. These, in turn, will add new threats to marine mammal populations, including ship strikes, contaminants, and competition for prey.
Timothy Ragen (US Marine Mammal Commission) and colleagues describe how conservation measures may be able to address the secondary effects of climate change, but that only reductions in greenhouse gas emissions can--over the long-term--conserve Arctic marine mammals and the Arctic ecosystems on which they depend.
Lead authors of the collection of papers in the Special Supplement to Ecological Applications are:
John Walsh (U. of AK, Fairbanks)--climatological understanding
C.R. Harrington (Canadian Museum of Nature)--evolutionary history of arctic marine mammals
Maribeth Murray (U. of AK, Fairbanks)--past distributions of arctic marine mammals
Gregory O'Corry-Crowe (Southwest Fisheries Science Center)--past and current distributions and behaviors
Bodil Bluhm (U. of AK, Fairbanks)--food availability and implications of climate change
Kristin Laidre (U. of WA)--sensitivity to climate-induced habitat change
Kathy Burek (Alaska Veterinary Pathology Services)--effects on Arctic marine mammal health
Grete Havelsrud (Center for International Climate & Environmental Research-Oslo)--human interactions
Vera Metcalf (Eskimo Walrus Commission, Kawerak)--walrus hunting
Sue Moore (NOAA/Alaska Fisheries Science Center)/Henry Huntington (Huntington Consulting)--resilience of Arctic marine mammals to climate change
Timothy Ragen (U.S. Marine Mammal Commission)--conservation in context of climate change
Adapted from materials provided by Ecological Society of America.

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Mercury In River Moves Into Terrestrial Food Chain Through Spiders Fed To Baby Birds

Source:

http://www.sciencedaily.com/releases/2008/04/080417175221.htm

ScienceDaily (Apr. 20, 2008) — Songbirds feeding near the contaminated South River are showing high levels of mercury, even though they aren’t eating food from the river itself, according to a paper published by William and Mary researchers in the journal Science.
Lead author Dan Cristol said his paper has wide-ranging international environmental implications. Mercury is one of the world’s most troublesome pollutants, especially in water. The South River, a major tributary of Virginia’s Shenandoah River, has been under a fish consumption advisory for years, as are some 3,000 other bodies of water in the U.S.
The paper shows high levels of mercury in birds feeding near, but not from, the South River. Cristol and his colleagues also identify the source of the pollutant—mercury-laden spiders eaten by the birds. The Science paper is one of the first, if not the first, to offer scientific documentation of the infiltration of mercury from a contaminated body of water into a purely terrestrial ecosystem.
“In bodies of water affected by mercury, it’s always been assumed that only birds or wildlife that ate fish would be in danger,” said Cristol, an associate professor in William and Mary’s Department of Biology. “But we’ve now opened up the possibility that mercury levels could be very high in the surrounding terrestrial habitat, as well. It’s not just about the fish, the people who eat the fish and the animals that eat the fish. We’ve also got to look at a strip of habitat all the way around the lake or river that is affected.”
Cristol and his co-authors, all students at the College of William and Mary, have been researching mercury impacts on birds along the South River for the past three years. The waters of the river were polluted with industrial mercury sulfate from around 1930 to 1950. He explained that mercury enters the food chain through a process called methylation, in which bacteria convert the mercury to a more potent form. The methylated mercury is passed up the food chain, becoming more concentrated in the bodies of larger animals through a phenomenon known as biomagnification.
Biomagnification of mercury in fish and fish-eating birds and other animals has been studied extensively, while little attention has been paid to the effects on animals near the river, but with no direct connection to the aquatic ecosystem. The researchers studied the food actually brought by songbird parents to their nestlings.
“The birds eat a lot of spiders. Spiders are like little tiny wolves, basically, and they’ll bioaccumulate lots of contaminants in the environment. The spiders have a lot of mercury in them and are delivering the mercury to these songbirds,” Cristol said. “The question that remains is this: How are the spiders getting their mercury?”
Cristol’s group is a part of the Institute for Integrated Bird Behavior Studies at William and Mary. Co-authors on the paper are master’s degree students Ariel E. White ’07, Rebecka L. Brasso ’07, Scott L. Friedman ’07 and Anne M. Condon ’08, along with undergraduates Rachel E. Fovargue ’09, Kelly K. Hallinger ’09 and Adrian P. Monroe ’08. Cristol and his group will continue their studies of the effect of mercury in the songbirds of the Shenandoah Valley, including an examination of the effects of the contaminant on the reproduction and lifespan of the birds.
Their paper appears in the April 18 issue of the journal Science.
Adapted from materials provided by The College of William & Mary.

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Almost Extinct Turtle Discovered Living In Wild In Northern Vietnam

Source:

http://www.sciencedaily.com/releases/2008/04/080416213653.htm

ScienceDaily (Apr. 19, 2008) — "Swinhoe's soft-shell turtle" was thought to be extinct in nature. Cleveland Metroparks Zoo has just announced the discovery of a critically endangered turtle in northern Vietnam that previously was thought to be extinct in the wild. Experts from the Zoo's Asian Turtle Program confirmed that they have identified the only known living specimen of a Swinhoe's soft-shell turtle (Rafetus swinhoei) in nature.
After three years of searching lakes and wetlands along the Red River in northern Vietnam, researchers sponsored by Cleveland Metroparks Zoo and the Cleveland Zoological Society, turned their focus to a lake just west of Hanoi, where local residents claimed to have occasionally seen the gigantic soft-shell turtle. Field biologist Nguyen Xuan Thuan, with Education for Nature in Vietnam, found and photographed the turtle as it basked on the lake's surface, allowing scientists to confirm the animal was the extremely rare Swinhoe's turtle.
This is an incredibly important discovery because the Swinhoe's turtle is one of the most critically endangered species of turtle in the world," said Doug Hendrie, the Vietnam-based coordinator of Cleveland Metroparks Zoo's Asian Turtle Program. "This species has legendary status among the people of Vietnam, so this is perhaps an opportunity for the legend to live on."
Other than the turtle discovered by Cleveland Metroparks Zoo's Asian Turtle Program, only three of the giant turtles are known to remain. Two of them are at zoos in China, and one is in the Hoan Kiem Lake in Hanoi. The Swinhoe's soft-shell turtle is considered by many in Vietnam to be a national treasure.
According to folklore, the rare turtle has emerged at key points in Vietnam's history. The legend says that in the 15th century, the giant turtle rose from Hoan Kiem Lake to reclaim a magical sword that was given to Emperor Le Loi to expel the Chinese army from Vietnam. Some people believe that the single, large soft-shell turtle that occupies the lake today is the very same turtle that retrieved the sword from the Emperor and returned it to God.
Hanoi residents often line the banks of Hoan Kiem Lake in hopes of spotting the legendary turtle, which some believe brings good fortune to those who see it.
"This is one of those mythical species that people always talked about but no one ever saw, so it's hugely significant that we found this lone turtle in the wild," said Geoff Hall, General Curator of Cleveland Metroparks Zoo. "It gives us some hope for a species that truly is on the verge of extinction."
The demise of this revered species is largely due to hunters who captured and killed them for food or to make traditional medicine from their bones. Loss of nesting habitats along major rivers and pollution also are to blame. And while the recent discovery of another specimen of the Swinhoe's turtle is promising, the future of the species remains uncertain.
"Our hopes are set on finding other turtles that have somehow been overlooked by hunters or were preserved in lakes and wetlands along the Red River," Hendrie said. "However, without evidence of reproduction, the future of the legendary Hoan Kiem turtle and its three surviving cohorts looks bleak."
Efforts are underway to unite the male and female soft-shell turtles at the two separate Chinese zoos in hopes they may reproduce and ensure another generation of the species.
The largest freshwater turtle in the world, the Swinhoe's soft-shell turtle also is referred to as the Shanghai soft-shell turtle or the Yangtze soft-shell turtle. The giant turtles can weigh up to 300 pounds and measure up to 3_ feet with some living to more than 100 years old. The species historically could be found in the Red River basin of northern Vietnam, extending north into southern China and along the Yangtze River in eastern China.
Before announcing their big discovery, the team of Zoo-supported researchers notified senior government officials and took measures to protect the turtle in its natural habitat. The Swinhoe's turtle remains in the lake where it was found.
The Asian Turtle Program is a special conservation program of Cleveland Metroparks Zoo and the Cleveland Zoological Society, with all work in Vietnam being carried out in partnership with Education for Nature -- Vietnam (ENV). Additional funding and support for the Asian Turtle Program comes from Conservation International, the Turtle Survival Alliance, the Wildlife Conservation Society, Melbourne Zoo, the Turtle Conservation Fund, the Wade Foundation and the Bachelor Foundation.
Cleveland Metroparks Zoo is home to 3,000 animals representing 600 species from six continents. Committed to improving the future for wildlife, the Zoo runs conservation initiatives both locally and abroad, supporting field scientists and conservation efforts in Asia, Latin America and Africa.
Adapted from materials provided by Cleveland Metroparks Zoo.

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Early Exposure To Common Weed Killer Impairs Amphibian Development

Source:

http://www.sciencedaily.com/releases/2008/04/080416091015.htm

ScienceDaily (Apr. 18, 2008) — Tadpoles develop deformed hearts and impaired kidneys and digestive systems when exposed to the widely used herbicide atrazine in their early stages of life, according to research by Tufts University biologists.

The results present a more comprehensive picture of how this common weed killer -- once thought to be harmless to animals -- disrupts growth of vital organs in amphibians during multiple growth periods.
In recent years, worldwide amphibian population declines have fueled concerns over the potentially harmful effects of pesticides on "sentinel" organisms. Previous research had revealed negative effects of atrazine on amphibians extremely early and late in development. The Tufts study, published in the February 2008 edition of "Environmental Health Perspectives," examined tadpoles during an often overlooked period of development, organ morphogenesis.
Study Results Broadens Knowledge of Herbicide's Effects During a Vulnerable Stage
Organ morphogenesis is a brief, extremely sensitive phase in the tadpoles' growth cycle when they are starting to develop organs, noted Kelly A. McLaughlin, Associate Professor of Biology and lead researcher in the study. She explained that experiments were designed to broaden the understanding of how chemicals affect biological growth in amphibians over multiple stages of development. A $5,000 Tufts University Faculty Research Marshall Grant helped fund the study.
"Amphibians are very vulnerable to contamination since atrazine is used in the same environs where they live and breed," McLaughlin said.
Atrazine is used to control broadleaf and grassy weeds on golf courses and residential lawns, according to the Federal Environmental Protection Agency. Farmers use it to treat corn and soybeans. Atrazine blocks photosynthesis once it is absorbed by plants. Chronic exposure to the herbicide during metamorphosis altered amphibian gonadal development, according to previous research.
To study the consequences of atrazine exposure during organ morphogenesis, McLaughlin and her colleagues, Professor of Biology J. Michael Reed, doctoral candidate Jenny R. Lenkowski and Lisa Deininger, a Summer Scholars program undergraduate student, collected eggs from adult female frogs and then fertilized them in vitro. Scientists exposed the developing tadpoles to 10, 25 and 35 mg/L of atrazine. The 35 mg/L dosage simulated the average amount of herbicide used when it is applied in the field, said McLaughlin.
Multiple Impacts
Twelve to 24 hours after exposure to atrazine, tadpoles were examined for abnormal heart growth, visceral hemorrhaging, intestinal coiling, edema and apoptosis (normal cell death that is "programmed" by the body).
Compared with control populations, the tadpoles that were exposed to atrazine had a dramatically higher incidence of abnormalities. The degree of deformities generally corresponded to the size of the dose. After 48 hours of exposure, the point at which organ development is disrupted most profoundly, 57 percent of the tadpoles exposed to 35 mg/L of atrazine had hearts that were smaller than normal, compared with 2% to 3% for the two control groups.
Ectopic Cell Death
The Tufts scientists also examined atrazine exposed tadpoles for increased incidence of apoptosis by measuring levels of active caspase-3 in the pronephric kidney and midbrain. Caspase-3 is a protein needed for apoptosis to occur. They conducted measurements after 6, 12, 24 and 48 hours of exposure in tadpoles exposed to 25 and 35 mg/l of atrazine. Researchers observed that the atrazine-exposed tadpoles showed significant increases in caspase-3 levels in the kidney and midbrain at 12 hours and beyond when compared with controls. The findings indicated a high incidence of ectopic, or abnormal, apoptosis.
"The increased levels of apoptosis in the midbrain and pronephric kidney we observe suggest that atrazine may cause tissue malformation by inducing ectopic programmed cell death, either directly or indirectly through a mechanism that has not been identified," wrote the researchers.
McLaughlin and her team hope that their findings will lay a foundation for further research to determine the underlying mechanism by which atrazine exposure can affect so many different organ systems during the same stage of early development.
"Our work here documents that atrazine affects amphibian's early development, so the second question is how is this happening?" she said. "We know it blocks photosynthesis in plants but why does it have such negative impact on amphibians?"
Adapted from materials provided by Tufts University, via EurekAlert!, a service of AAAS.

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Hawaiian Plant, Thought To Be Newcomer, Actually Shaped Ecology Of The Islands From The Beginning

Source:

http://www.sciencedaily.com/releases/2008/04/080415210623.htm

ScienceDaily (Apr. 18, 2008) — Scientists at the Smithsonian Institution have discovered data that suggests one of Hawaii's most dominant plants, Metrosideros, has been a resident of the islands far longer than previously believed.

Metrosideros, commonly called "ohi'a" in the Hawaiian Islands, has puzzled researchers for years. Although previously thought to be a newcomer to the islands, these plants are well integrated into the islands' ecosystems.
However, scientists from the Smithsonian's National Museum of Natural History and the Smithsonian's National Zoo now are able to show, through molecular research, that Metrosideros may have colonized the islands soon after they formed. If so, these plants would have played an important role in shaping the ecology of the islands from the beginning.
The isolated Hawaiian Islands are home to many unique and endemic species of plants and animals. To know how these species came to interact with one another and form functioning ecosystems, scientists must first know how and when each species came to be on the islands. This is particularly important in the case of Metrosideros--many species of birds and insects are specialized to coexist and feed on these plants. Knowing when Metrosideros dispersed and colonized the islands also will give scientists a better understanding of how and when the fauna that rely on them evolved.
Until now, no definitive phylogeographical study (combining evolutionary history with current distribution patterns in order to understand both) has been done on ecologically dominant species in this island group.
"What we are finding," said Scott Miller, a Smithsonian scientist working on the project, "is a distinct geographical pattern that supports a hypothesis that these plants colonized the Hawaiian Islands sequentially as they formed." This could prove that Metrosideros played a far more important role in Hawaii's ecology than once thought.
Scientists at the Smithsonian will continue to research Metrosideros in Hawaii to further determine the plant's historical colonization pattern and its influence and role in the biodiversity of the islands.
Their findings are being published in the journal Proceedings of the Royal Society B in London on April 16.
Adapted from materials provided by Smithsonian, via EurekAlert!, a service of AAAS.

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Lizards Undergo Rapid Evolution After Introduction To A New Home

Source:

http://www.sciencedaily.com/releases/2008/04/080417112433.htm

ScienceDaily (Apr. 18, 2008) — In 1971, biologists moved five adult pairs of Italian wall lizards from their home island of Pod Kopiste, in the South Adriatic Sea, to the neighboring island of Pod Mrcaru. Now, an international team of researchers has shown that introducing these small, green-backed lizards, Podarcis sicula, to a new environment caused them to undergo rapid and large-scale evolutionary changes.
“Striking differences in head size and shape, increased bite strength and the development of new structures in the lizard’s digestive tracts were noted after only 36 years, which is an extremely short time scale,” says Duncan Irschick, a professor of biology at the University of Massachusetts Amherst. “These physical changes have occurred side-by-side with dramatic changes in population density and social structure.”
Researchers returned to the islands twice a year for three years, in the spring and summer of 2004, 2005 and 2006. Captured lizards were transported to a field laboratory and measured for snout-vent length, head dimensions and body mass. Tail clips taken for DNA analysis confirmed that the Pod Mrcaru lizards were genetically identical to the source population on Pod Kopiste.
Observed changes in head morphology were caused by adaptation to a different food source. According to Irschick, lizards on the barren island of Pod Kopiste were well-suited to catching mobile prey, feasting mainly on insects. Life on Pod Mrcaru, where they had never lived before, offered them an abundant supply of plant foods, including the leaves and stems from native shrubs. Analysis of the stomach contents of lizards on Pod Mrcaru showed that their diet included up to two-thirds plants, depending on the season, a large increase over the population of Pod Kopiste.
“As a result, individuals on Pod Mrcaru have heads that are longer, wider and taller than those on Pod Kopiste, which translates into a big increase in bite force,” says Irschick. “Because plants are tough and fibrous, high bite forces allow the lizards to crop smaller pieces from plants, which can help them break down the indigestible cell walls.”
Examination of the lizard’s digestive tracts revealed something even more surprising. Eating more plants caused the development of new structures called cecal valves, designed to slow the passage of food by creating fermentation chambers in the gut, where microbes can break down the difficult to digest portion of plants. Cecal valves, which were found in hatchlings, juveniles and adults on Pod Mrcaru, have never been reported for this species, including the source population on Pod Kopiste.
“These structures actually occur in less than 1 percent of all known species of scaled reptiles,” says Irschick. “Our data shows that evolution of novel structures can occur on extremely short time scales. Cecal valve evolution probably went hand-in-hand with a novel association between the lizards on Pod Mrcaru and microorganisms called nematodes that break down cellulose, which were found in their hindguts.”
Change in diet also affected the population density and social structure of the Pod Mrcaru population. Because plants provide a larger and more predictable food supply, there were more lizards in a given area on Pod Mrcaru. Food was obtained through browsing rather than the active pursuit of prey, and the lizards had given up defending territories.
“What is unique about this finding is that rapid evolution can affect not only the structure and function of a species, but also influence behavioral ecology and natural history,” says Irschick.
Results of the study were published March 25 in Proceedings of the National Academy of Sciences. This research was supported by the National Science Foundation and the Fund for Scientific Research in Flanders. Additional members of the research team include Anthony Herrel of Harvard University and the University of Antwerp, Kathleen Huyghe, Bieke Vanhooydonck, Thierry Backeljau and Raoul Van Damme of the University of Antwerp, Karin Breugelmans of the Royal Belgian Institute of Natural Sciences and Irena Grbac of the Croatian Natural History Museum.
Adapted from materials provided by University Of Massachusetts, Amherst.

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Presumed Extinct Javan Elephants May Have Been Found Again - In Borneo

Source:

http://www.sciencedaily.com/releases/2008/04/080416223340.htm

ScienceDaily (Apr. 18, 2008) — The Borneo pygmy elephant may not be native to Borneo after all. Instead, the population could be the last survivors of the Javan elephant race – accidentally saved from extinction by the Sultan of Sulu centuries ago, a new publication suggests.
The origins of the pygmy elephants, found in a range extending from the north-east of the island into the Heart of Borneo, have long been shrouded in mystery. Their looks and behaviour differ from other Asian elephants and scientists have questioned why they never dispersed to other parts of the island.
But a new paper published supports a long-held local belief that the elephants were brought to Borneo centuries ago by the Sultan of Sulu, now in the Philippines, and later abandoned in the jungle. The Sulu elephants, in turn, are thought to have originated in Java.
Javan elephants became extinct some time in the period after Europeans arrived in South-East Asia. Elephants on Sulu, never considered native to the island, were hunted out in the 1800s.
“Elephants were shipped from place to place across Asia many hundreds of years ago, usually as gifts between rulers,” said Mr Shim Phyau Soon, a retired Malaysian forester whose ideas on the origins of the elephants partly inspired the current research. “It’s exciting to consider that the forest-dwelling Borneo elephants may be the last vestiges of a subspecies that went extinct on its native Java Island, in Indonesia, centuries ago.”
If the Borneo pygmy elephants are in fact elephants from Java, an island more than 1,200 km (800 miles) south of their current range, it could be the first known elephant translocation in history that has survived to modern times, providing scientists with critical data from a centuries-long experiment.
Scientists solved part of the mystery in 2003, when DNA testing by Columbia University and WWF ruled out the possibility that the Borneo elephants were from Sumatra or mainland Asia, where the other Asian subspecies are found, leaving either Borneo or Java as the most probable source.
The new paper, “Origins of the Elephants Elephas Maximus L. of Borneo,” published in this month’s Sarawak Museum Journal shows that there is no archaeological evidence of a long-term elephant presence on Borneo.
“Just one fertile female and one fertile male elephant, if left undisturbed in enough good habitat, could in theory end up as a population of 2,000 elephants within less than 300 years,” said Junaidi Payne of WWF, one of the paper’s co-authors. “And that may be what happened in practice here.”
There are perhaps just 1,000 of the elephants in the wild, mostly in the Malaysian state of Sabah. WWF satellite tracking has shown they prefer the same lowland habitat that is being increasingly cleared for timber rubber and palm oil plantations. Their possible origins in Java make them even more a conservation priority.
“If they came from Java, this fascinating story demonstrates the value of efforts to save even small populations of certain species, often thought to be doomed,” said Dr Christy Williams, coordinator of WWF’s Asian elephant and rhino programme. “It gives us the courage to propose such undertakings with the small remaining populations of critically endangered Sumatran rhinos and Javan rhinos, by translocating a few to better habitats to increase their numbers. It has worked for Africa’s southern white rhinos and Indian rhinos, and now we have seen it may have worked for the Javan elephant, too.”
Adapted from materials provided by World Wildlife Fund.

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World's Oldest Living Tree -- 9550 years old -- Discovered In Sweden

Source:

http://www.sciencedaily.com/releases/2008/04/080416104320.htm

ScienceDaily (Apr. 16, 2008) — The world's oldest recorded tree is a 9,550 year old spruce in the Dalarna province of Sweden. The spruce tree has shown to be a tenacious survivor that has endured by growing between erect trees and smaller bushes in pace with the dramatic climate changes over time.

For many years the spruce tree has been regarded as a relative newcomer in the Swedish mountain region. "Our results have shown the complete opposite, that the spruce is one of the oldest known trees in the mountain range," says Leif Kullman, Professor of Physical Geography at Umeå University.
A fascinating discovery was made under the crown of a spruce in Fulu Mountain in Dalarna. Scientists found four "generations" of spruce remains in the form of cones and wood produced from the highest grounds.
The discovery showed trees of 375, 5,660, 9,000 and 9,550 years old and everything displayed clear signs that they have the same genetic makeup as the trees above them. Since spruce trees can multiply with root penetrating braches, they can produce exact copies, or clones.
The tree now growing above the finding place and the wood pieces dating 9,550 years have the same genetic material. The actual has been tested by carbon-14 dating at a laboratory in Miami, Florida, USA.
Previously, pine trees in North America have been cited as the oldest at 4,000 to 5,000 years old.
In the Swedish mountains, from Lapland in the North to Dalarna in the South, scientists have found a cluster of around 20 spruces that are over 8,000 years old.
Although summers have been colder over the past 10,000 years, these trees have survived harsh weather conditions due to their ability to push out another trunk as the other one died. "The average increase in temperature during the summers over the past hundred years has risen one degree in the mountain areas," explains Leif Kullman.
Therefore, we can now see that these spruces have begun to straighten themselves out. There is also evidence that spruces are the species that can best give us insight about climate change.
The ability of spruces to survive harsh conditions also presents other questions for researchers.
Have the spruces actually migrated here during the Ice Age as seeds from the east 1,000 kilometres over the inland ice that that then covered Scandinavia? Do they really originate from the east, as taught in schools? "My research indicates that spruces have spent winters in places west or southwest of Norway where the climate was not as harsh in order to later quickly spread northerly along the ice-free coastal strip," says Leif Kullman.
"In some way they have also successfully found their way to the Swedish mountains."
The study has been carried out in cooperation with the County Administrative Boards in Jämtland and Dalarna.
Adapted from materials provided by Umeå University.

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Bikini Corals Recover From Atomic Blast, Although Some Species Missing

Source:

http://www.sciencedaily.com/releases/2008/04/080415101021.htm

ScienceDaily (Apr. 16, 2008) — Half a century after the last earth-shattering atomic blast shook the Pacific atoll of Bikini, the corals are flourishing again. Some coral species, however, appear to be locally extinct.

These are the findings of a remarkable investigation by an international team of scientists from Australia, Germany, Italy, Hawaii and the Marshall Islands. The expedition examined the diversity and abundance of marine life in the atoll.
One of the most interesting aspects is that the team dived into the vast Bravo Crater left in 1954 by the most powerful American atom bomb ever exploded (15 megatonnes - a thousand times more powerful than the Hiroshima bomb). The Bravo bomb vapourised three islands, raised water temperatures to 55,000 degrees, shook islands 200 kilometers away and left a crater 2km wide and 73m deep.
After diving into the crater, Zoe Richards of the ARC Centre of Excellence for Coral Reef Studies and James Cook University says, “I didn’t know what to expect – some kind of moonscape perhaps. But it was incredible, huge matrices of branching Porites coral (up to 8 meters high) had established, creating thriving coral reef habitat. Throughout other parts of the lagoon it was awesome to see coral cover as high as 80 per cent and large tree-like branching coral formations with trunks 30cm thick. It was fascinating – I’ve never seen corals growing like trees outside of the Marshall Islands.
“The healthy condition of the coral at Bikini atoll today is proof of their resilience and ability to bounce back from massive disturbances, that is, if the reef is left undisturbed and there are healthy nearby reefs to source the recovery.”
However the research has also revealed a disturbingly high level of loss of coral species from the atoll. Compared with a famous study made before the atomic tests were carried out, the team established that 42 species were missing compared to the early 1950s. At least 28 of these species losses appear to be genuine local extinctions probably due to the 23 bombs that were exploded there from 1946-58, or the resulting radioactivity, increased nutrient levels and smothering from fine sediments.
“The missing corals are fragile lagoonal specialists – slender branching or leafy forms that you only find in the sheltered waters of a lagoon,” Zoe explains. While corals in general have shown resilience, Zoe adds that the coral biodiversity at Bikini Atoll has proven only partially resilient to the disturbances that have occurred there.
Maria Beger from the Commonwealth Research Facility for Applied Environmental Decision Analysis at The University of Queensland took a Geiger counter with her on the expedition.
“The ambient gamma radiation the residential island of Bikini atoll was fairly low – pretty much like the background radiation in an Australian city. However when I put the Geiger counter near a coconut, which accumulates radioactive material from the soil, it went berserk,” Maria remembers.
Extensive decontamination works have been carried out at Bikini atoll making it safe to visit, however local produce is unsafe to eat, and it is unlikely the Bikinian people will return to live on Bikini Atoll in the near future.
The coral survey was carried out at the request of the atoll’s local government.
For comparison the team also dived on neighbouring Rongelap Atoll, where no atomic tests were carried out directly although the atoll was contaminated by radioactive ash from the Bravo Bomb and local inhabitants were also evacuated and for the most part, have not returned. The marine environment at this Atoll was found to be in a pristine condition.
The team thinks that Rongelap Atoll is potentially seeding Bikini’s recovery, because it is the second largest atoll in the world with a huge amount of coral reef diversity and biomass and lies upstream from Bikini.
Zoe says that ironically, thanks to the bombs, Bikini Atoll represents a priceless laboratory showing how in the absence of ongoing stress, some corals have the capacity to recover from vast upheavals, which may contain valuable lessons for the management of reefs in other parts of the world including Australia.
“Apart from occasional forays of illegal shark, tuna and Napoleon Wrasse fishing, the reef is almost completely undisturbed to this day. There are very few local inhabitants and the divers who visit dive on shipwrecks, like the USS Saratoga, and not on the reef” says Maria.”
Because of its incredible history and current undisturbed character Bikini Atoll is now part of a larger project to have northern Marshall Island Atolls World Heritage listed. The expedition served to illustrate the tragic history of the Bikinian people is not entirely reflected below the surface because the reefs of Bikini are recovering to present themselves as havens of abundance to the marine life of the Northern Pacific Ocean.
The team’s report on Bikini corals surviving atom bombs appears in Elsevier’s Marine Pollution Bulletin No. 56, March 2008 page 5-3-1-515.
Adapted from materials provided by ARC Centre of Excellence in Coral Reef Studies.

Fausto Intilla - www.oloscience.com

Ancient Komodo Dragon Has Space-age Skull

Source:

http://www.sciencedaily.com/releases/2008/04/080414091357.htm

ScienceDaily (Apr. 14, 2008) — The fearsome Komodo dragon is the world's largest living lizard and can take very large animal prey: now a new international study has revealed how it can be such an efficient killing machine despite having a wimpy bite and a featherweight skull.

A member of the goanna family with ancestors dating back more than 100 million years, the dragon (Varanus komodoensis) uses a combination of 60 razor-sharp serrated teeth, powerful neck muscles and what researchers are calling a "space-frame" skull to butcher prey with awesome efficiency, the study found.
They note that the dragon -- inhabiting the central Indonesian islands of Komodo, Rinca, Flores, Gili Motang and Gili Dasami -- shares the feeding and dental characteristics of extinct dinosaurs, sharks and sabre-toothed cats. Scientists Karen Moreno and Stephen Wroe from the University of New South Wales have used a computer-based technique called Finite Element Analysis (FEA) to test the bite force and feeding mechanics of the predator. Their findings are to be published in the latest issue of the Journal of Anatomy.
Normally used in the analysis of trains, planes and cars, the technique allowed the team to "reverse engineer" nature's design to assess the mechanical forces that a Komodo skull can handle. "The Komodo has a featherweight, space-frame skull and bites like a wimp," according to Wroe, "but a combination of very clever engineering, and wickedly sharp teeth, allow it to do serious damage to even buffalo-sized prey.
"The Komodo displays a unique hold and pull-feeding technique," says Dr Wroe. "Its delicate skull differs greatly from most living terrestrial large prey specialists, but it's a precision instrument, beautifully optimised to make the most of its natural cranial and dental properties.
"Unlike most modern predators, Varanus komodoensis applies minimal input from the jaw muscles when killing and butchering prey. But it compensates using a series of actions controlled by its postcranial muscles. A particularly interesting feature of the skull's performance is that it reveals considerably lower overall stress when these additional forces driven by the neck are added to those of the jaw-closing muscles.
"This remarkable reduction in stress in response to additional force is facilitated partly by the shape of the bones, but also by the way bone of different strengths are arranged within the skull."
The Komodo dragon grows to an average length of two to three metres and weighing around 70 kilograms. The reptile's unusual size is attributed to island gigantism, since there are no other carnivorous mammals to fill the niche on the islands where they live. As a result of their size, these lizards are apex predators, dominating the ecosystems in which they live. Although Komodo dragons eat mostly carrion, they will also hunt and ambush prey including invertebrates, birds, and mammals.
Its saliva is frequently blood-tinged, because its teeth are almost completely covered by gingival tissue that is naturally lacerated during feeding. Discovered by Western scientists in 1910, the Komodo dragon's large size and fearsome reputation makes it a popular zoo exhibit. In the wild its total population is estimated at 4,000-5,000: its range has contracted due to human activities and it is listed as vulnerable by the IUCN.
Adapted from materials provided by University of New South Wales, via EurekAlert!, a service of AAAS.

Fausto Intilla - www.oloscience.com

Insects Evolved Radically Different Strategy To Smell

Source: http://www.sciencedaily.com/releases/2008/04/080413161035.htm

ScienceDaily (Apr. 14, 2008) — Darwin's tree of life represents the path and estimates the time evolution took to get to the current diversity of life. Now, new findings suggest that this tree, an icon of evolution, may need to be redrawn. In research to be published in the April 13 advance online issue of Nature, researchers at Rockefeller University and the University of Tokyo have joined forces to reveal that insects have adopted a strategy to detect odors that is radically different from those of other organisms -- an unexpected and controversial finding that may dissolve a dominant ideology in the field.

Since 1991, researchers assumed that all vertebrates and invertebrates smell odors by using a complicated biological apparatus much like a Rube Goldberg device. For instance, someone pushing a doorbell would set off a series of elaborate, somewhat wacky, steps that culminate in the rather simple task of opening the door.
In the case of an insect's ability to smell, researchers believed that when molecules wafting in the air travel up the insect's nose, they latch onto a large protein (called a G-protein coupled odorant receptor) on the surface of the cell and set off a chain of similarly elaborate steps to open a molecular gate nearby, signaling the brain that an odor is present.
"It's that way in the nematode, it's that way in mammals, it's that way in every known vertebrate," says study co-author Leslie Vosshall, head of the Laboratory of Neurogenetics and Behavior at Rockefeller University. "So it's actually unreasonable to think that insects use a different strategy to detect odors. But here, we show that insects have gotten rid of all this stuff in the middle and activate the 'gate' directly."
The gate, a doughnut-shaped protein called an ion channel, provides a safe pathway for ions to flow into a cell. When molecules bind to the odor-sensitive ion channel, the protein changes its shape much like a gate or door changes its conformation as it is opened and closed. Opened, it allows millions of ions to surge into the cell. Closed, it prohibits the activity of the ions from sending a signal to the brain that an odor is present.
At the University of Tokyo, Vosshall's colleague Kazushige Touhara and his lab members puffed molecules onto cells engineered to make insect olfactory receptors. They then measured how long it took for the ion channel to open and recorded their electrical movement as they surged inside the cell via the channel. The rush of electrical activity occurred too fast for a series of steps to be involved, says Vosshall. In addition, poisoning several proteins involved in the G-protein pathway didn't affect the ions or the ion channel, suggesting that G-protein signaling isn't primarily involved in insect smell.
Experiment after experiment, "the most consistent interpretation is that these are ion channels directly gated by odors," says Vosshall. "But the dominant thinking in the field may have reflected an experimental bias that aimed at proving a more elaborate scheme."
The ion channels don't resemble any known ion channel on Earth, says Vosshall. They are composed of two proteins that work in tandem with one another: an olfactory receptor and its coreceptor, Or83b. While the coreceptor is common to every ion channel, the olfactory receptor is unique. Together, they form the olfactory receptor complex. Vosshall and Touhara specifically show that this complex forms nonselective cation channels, meaning that they allow any ion to pass through the gate as long as it has a positive charge.
Touhara and Vosshall developed their ion channel hypothesis in parallel with Vosshall's work on DEET, a widely used chemical in bug spray that jams the receptor complex. This research, which was published in Science last month, also showed that DEET jams other proteins that have nothing to do with smell, including several different types of ion channels that play important roles in the human nervous system. What these radically different proteins have in common, though, is that they all specifically inhibit the influx of positively charged ions into the cell. "Now the curious result in the DEET paper showing that this insect repellent blocks insect olfactory receptors and unrelated ion channels makes sense," says Vosshall. "I am optimistic that we can come up with blockers specific for this very strange family of insect olfactory ion channels."
This research was supported in part by the Foundation for the National Institutes of Health through the Grand Challenges in Global Health Initiative, the National Institutes of Health's U.S.-Japan Brain Research Collaborative Program and the Japan Society for the Promotion of Science's Japan-U.S. Cooperative Science Program.
Adapted from materials provided by Rockefeller University, via EurekAlert!, a service of AAAS.

Fausto Intilla - www.oloscience.com

First Lungless Frog Discovered

Source: http://www.sciencedaily.com/releases/2008/04/080407123824.htm

ScienceDaily (Apr. 8, 2008) — Researchers have confirmed the first case of complete lunglessness in a frog, according to a report in the April 8th issue of Current Biology. The aquatic frog Barbourula kalimantanensis apparently gets all the oxygen it needs through its skin.
Previously known from only two specimens, two new populations of the aquatic frog were found by the team during a recent expedition to Indonesian Borneo.
"We knew that we would have to be very lucky just to find the frog," said David Bickford of the National University of Singapore. "People have been trying for 30 years. But when we did and I was doing the initial dissections -- right there in the field -- I have to say that I was very skeptical at first [that they would in fact lack lungs]. It just did not seem possible. We were all shocked when it turned out to be true for all the specimens we had from Kalimantan, Indonesia.
"The thing that struck me most then and now is that there are still major firsts (e.g., first lungless frog!) to be found out in the field," he added. "All you have to do is go a little ways beyond what people have done before, and -- voila!"
Of all tetrapods (animals with four limbs), lunglessness is only known to occur in amphibians. There are many lungless salamanders and a single species of caecilian, a limbless amphibian resembling an earthworm, known to science. Nevertheless, Bickford said, the complete loss of lungs is a particularly rare evolutionary event that has probably only occurred three times.
The discovery of lunglessness in a secretive Bornean frog supports the idea that lungs are a malleable trait in amphibians, which represent the evolutionary sister group to all other tetrapods, according to the researchers. Barboroula kalimantanensis lives in cold, fast-flowing water, they noted, so loss of lungs might be an adaptation to a combination of factors: a higher oxygen environment, the species's presumed low metabolic rate, severe flattening of their bodies that increases the surface area of their skin, and selection for negative buoyancy--meaning that the frogs would rather sink than float.
The researchers said that further studies of this remarkable frog may be hampered by the species' rarity and endangerment. They therefore strongly encourage conservation of the frogs' remaining habitats.
"This is an endangered frog -- that we know practically nothing about -- with an amazing ability to breathe entirely through its skin, whose future is being destroyed by illegal gold mining by people who are marginalized and have no other means of supporting themselves," Bickford said. "There are no simple answers to this problem."
The researchers include David Bickford, National University of Singapore, Singapore; Djoko Iskandar and Anggraini Barlian, of Institut Teknologi Bandung, Java, Indonesia.
Adapted from materials provided by Cell Press, via EurekAlert!, a service of AAAS.

Fausto Intilla
www.oloscience.com