June 13, 2007, 9:47 AM CT

Massive Migration Revealed

Seen thundering across the landscape during an aerial survey, more than 1.3 million white-eared kob, tiang (African antelope), and mongalla gazelle are thriving in Southern Sudan, despite all odds. An estimated 8,000 elephants, concentrated mainly in the Sudd, the largest freshwater wetland in Africa, have also been observed. Researchers are astonished at the latest news: Based on experiences in other war-torn regions such as Mozambique and Angola, they believed wildlife had vanished from this area.

"I have never seen wildlife in such numbers, not even when flying over the mass migrations of the Serengeti," said J. Michael Fay, who conducted the surveys. Fay is a field scientist with the Wildlife Conservation Society (WCS) and a National Geographic Explorer-in-Residence. "This could represent the biggest migration of large mammals on Earth".

Paul Elkan, director of the WCS Southern Sudan Country Program, and Malik Marjan, a Southern Sudanese Ph.D. candidate from the University of Massachusetts Amherst, worked alongside Fay on the project. The team collaborated with the Ministry of the Environment, Wildlife Conservation, and Tourism of the Government of Southern Sudan (GoSS). USAID/Sudan and the U.S. Fish & Wildlife Service provided additional funding.

WCS last surveyed southern Sudan in 1982, one year before civil war broke out. During the decades-long war with northern Sudan, political obstacles and conflict precluded further scientific studies there. As part of a 2005 peace agreement, Southern Sudan formed an autonomous region and will hold a referendum on independence in 2011......... Posted by: Kelly      Read more         Source

June 13, 2007, 8:38 AM CT

Rove beetles act as warning signs

New research from the University of Alberta and the Canadian Forest Service has revealed the humble rove beetle may actually have a lot to tell us about the effects of harvesting on forests species. Rove beetles can be used as indicators of clear-cut harvesting and regeneration practices and can be used as an example as to how species react to harvesting. It has been observed that after an area of forest was harvested, the a number of forest species, including rove beetles, decreased dramatically. As the forest regenerated, it never fully replicated the full characteristics of the older forest it replaced.

As insects are the most abundant animal species in forests, they have enormous potential as indicators of habitat change and recovery and are increasingly being used in conservation studies.

We felt beetles were excellent candidates for this study because they are abundant and diverse, easily sampled, inhabit a variety of niches and are very sensitive to habitat change, said John Spence, professor of Renewable Resources at the University of Alberta.

A total of 13, 978 rove beetles were collected and 98 species were identified during this study.

Once the forest was harvested the overall abundance of rove beetles declined while the diversity of species increased. Also most mature forest-dwelling species became much less abundant or disappeared completely immediately after harvest. Even the low amount of mature forest beetles that survived the initial harvest would eventually die out or migrate elsewhere within a few years of harvest......... Posted by: Kelly      Read more         Source

June 13, 2007, 8:17 AM CT

Preserving Arctic Whale

Research on one of the oldest-living mammals - the bowhead whale - has helped preserve a primary food source for Eskimos in the far reaches of Alaska, and also may provide a useful tool for studying genetic variation in other migratory animals.

The bowhead whale, devastated in the 19th and early 20th centuries by commercial whaling fleets, has been a food staple for Eskimos and other indigenous arctic peoples dating to prehistoric times. Due in part to research done by Purdue University professor John Bickham, the International Whaling Commission ruled last week to allow Eskimos to harvest 56 whales per year, the same quota that had been in place but had expired.

"Eskimos have been whaling for more than 2,000 years and have never endangered the bowhead whale," said Bickham, the professor of forestry and natural resources who presented data from a study he co-authored at the scientific meeting of the commission in May.

Bickham said the bowhead's population has recently been increasing by 3 percent a year, even while being harvested by subsistence hunters. The bowhead, he said, which can be 50 feet long and weigh 50 tons, should be able to increase its 11,000 population under the quota.

At the commission meeting, which ended May 31, the 76 member nations voted to renew the subsistence hunt quota for the next five years. Members of the Alaska Eskimo Whaling Commission, worried the quota might not be renewed, celebrated the news......... Posted by: Kelly      Read more         Source

June 13, 2007, 7:30 AM CT

Divorce Among Galapagos Seabirds

Being a devoted husband and father is not enough to keep an avian marriage together for the Nazca booby, a long-lived seabird found in the Galapagos Islands off the coast of Ecuador.

A number of Nazca booby females switch mates after successfully raising a chick, as per a Wake Forest University study scheduled for publication in the journal Proceedings of the Royal Society B: Biological Sciences June 13.

This is surprising because there is an advantage to staying together, said Terri Maness, a doctoral student who co-authored the study with David J. Anderson, professor of biology at Wake Forest. The chance of successfully breeding probably improves as the pairs of birds get older and are together longer, as has been found in other birds.

But, often the female seeks a divorce after a few breeding seasons. Since males significantly outnumber females in the colony studied, there are plenty of bachelors available if the female has a wandering eye.

Our study population has 50 percent more males than females, creating the opportunity for females to trade a current mate, which may be worn-out from recent breeding effort, for a refreshed non-breeding male, Maness said.

It takes a lot of energy to raise a chick and the responsibility is shared by both males and females. They raise one chick at a time. Parents incubate the egg for 43 days. Then, it takes another 100 to 120 days of parental care until the baby bird can fly. The parents will commonly continue to provide some meals to the fledgling......... Posted by: Kelly      Read more         Source

June 11, 2007, 4:22 PM CT

Crammed with Charged DNA

It could be an artist's depiction of someone's stomach before and after a rather decadent meal. But it is a 3-D cryoelectron microscope reconstruction of the cross-section of a virus, before and after cramming itself full of its own DNA.

The virus, phi29, has a tiny motor that pumps its DNA into the capsid-outer shell-during the assembly process. The potential energy of the tightly coiled DNA may help phi29 inject its genetic material into the bacterial cells it infects. Now a team led by physicists at the University of California, San Diego has used laser tweezers to measure the forces exerted by the motor as it pushes the DNA into the capsid.

"The virus' motor has to do mechanical work to overcome two factors that create resistance," said Douglas Smith, an assistant professor of physics at UCSD who headed the team that published the discovery this week in the early on-line edition of Proceedings of the National Academy of Sciences. "First, the DNA must be forced to bend. Second, the electrostatic repulsion of the DNA's negatively charged backbone must be overcome. We observed that the positively charged ions in the solution are critical to overcoming this repulsion. Without the right combination of positively charged ions, the virus could not force all of its DNA into the capsid"......... Posted by: Janet      Read more         Source

June 11, 2007, 4:13 PM CT

Climate Change, Deforestation And Global Bird Diversity

Global warming and the destruction of natural habitats will lead to significant declines and extinctions in the world's 8,750 terrestrial bird species over the next century, as per a research studyconducted by biologists at the University of California, San Diego and Princeton University.

Their study, the first global assessment of how climate change and habitat destruction may interact to impact the distribution of a large group of vertebrates over the next century, appears in the June 5 issue of the journal PLoS Biology.

The researchers warn in their study that, even under the most optimistic scenarios of controlling climate change and protecting habitats, at least 400 bird species are projected to become imperiled by the year 2050 due to reductions in their geographic ranges of greater than 50 percent. All estimates in the study are based on the assumption that birds will not dramatically shift their geographic ranges in response to a changing climate.

"We found in our study that under certain assumptions by the year 2100, 950 to 1,800 bird species may be imperiled or even driven to extinction by climate change and habitat destruction," says Walter Jetz, an assistant professor of biological sciences at UCSD and the lead author of the study. "Most of these species are currently not recognized as imperiled"......... Posted by: Kelly      Read more         Source

June 10, 2007, 9:01 PM CT

Columbine Flowers Develop Long Nectar Spurs

In flowers called columbines, evolution of the length of nectar spurs--the long tubes leading to plants' nectar--happens in a way that allows flowers to match the tongue lengths of the pollinators that drink their nectar, biologists have found.

The scientists were Justen Whittall of the University of California at Davis and Scott Hodges of the University of California at Santa Barbara. They were funded by the National Science Foundation (NSF). Their results appear in this week's issue of the journal Nature.

Darwin once proposed a co-evolutionary "race" to explain how natural selection might account for the evolution of very long nectar spurs in flowers, said Hodges. "In Darwin's race, plants with the longest spurs and pollinators with the longest tongues [to tap the flowers' nectar] would be favored by natural selection, and--in a never-ending process--continually drive the plants' spurs and the pollinator tongues to exceptionally long lengths".

But it turns out, Whittall and Hodges found, that evolution acts in a more one-sided fashion in a number of plants: the plants evolve nectar spurs to match the tongue-lengths of the pollinators. Then the process stops, and only starts again when there is a change in pollinators.

Whittall and Hodges proved this idea by testing the columbine genus Aquilegia, which is pollinated by bumblebees, hummingbirds and hawkmoths......... Posted by: Erica      Read more         Source

June 10, 2007, 8:59 PM CT

History of Caribbean Frog Population

Nearly all of the 162 land-breeding frog species on Caribbean islands, including the coqui frogs of Puerto Rico, originated from a single frog species that arrived on a sea voyage from South America. They came 30 to 50 million years ago, as per DNA-sequence analyses by researchers at Penn State.

Similarly, the researchers observed that the Central American relatives of these Caribbean amphibians also arose from a single species that arrived by raft from South America.

"This discovery is surprising because no prior theories of how the frogs arrived had predicted a single origin for Caribbean terrestrial frogs, and because groups of close relatives rarely dominate the fauna of an entire continent or major geographic region," said Blair Hedges of Penn State, an evolutionary biologist who directed the research. "Because connections among continents have allowed land-dwelling animals to disperse freely over millions of years, the fauna of any one continent is commonly a composite of a number of types of animals".

The results would be reported in the June 12, 2007 issue of the Proceedings of the National Academy of Sciences and posted in the journal's online early edition this week.

The field work for the study mandatory nearly three decades to complete because a number of of the species are restricted to remote and isolated mountain tops or other inaccessible areas. Some species included in the study are thought to beextinct because of habitat degradation and other causes......... Posted by: Kelly      Read more         Source

June 10, 2007, 7:35 PM CT

Oxygen trick could see organic costs tumble

A simple, cheap therapy using just oxygen could allow growers to store organic produce for longer and go a long way towards reducing the price of organic fruit and vegetables, reports Lisa Richards in Chemistry & Industry, the magazine of the SCI.

Currently UK shoppers have to pay twice as much for some organic products. Organic apples, for example, are around double the price of conventionally grown apples in Sainburys, Waitrose and Tesco.

One of the major contributing factors affecting the price is the short shelf life of organic produce. Conventional produce can be treated with inexpensive chemicals to aid preservation. But these cannot be used for organic produce, as by definition no artificial chemicals are used during processing.

With some organic fruit and veg, there can be large losses [during storage], Claudia Ruane, spokes person for Abel & Cole organic produce retailers told C&I. Ruane explained that eventhough a number of organic farms do have reasonably sophisticated refrigeration units, there are very expensive and used only for brief storage before collection. These are important and costly but if paying out for these facilities can ensure a whole crop is not rejected by a retailer because it is a little limp or dehydrated, then it is a cost that has to be absorbed, she said......... Posted by: Erica      Read more         Source

June 7, 2007, 7:37 PM CT

Chimpanzees Can Sustain Multiple-tradition Cultures

Researchers have long wondered if local animal cultures exist, and now, based on findings by scientists at the Yerkes National Primate Research Center at Emory University, the University of Texas and St. Andrews University, Scotland, they have their answer: Yes.

The study, available in todays online edition of Current Biology, confirms captive chimpanzees have the capacity to sustain the same kind of multiple-tradition cultures a number of scientists believe exist in the wild, providing further evidence chimpanzees and humans shared a common ancestor five to six million years ago who had a similar level of cultural complexity.

For years, primatologists have suggested different communities of chimpanzees across Africa vary in a number of behavior patterns, indicating they have cultures specific to each community. In the wild, however, it is difficult to prove behaviors are passed on by observation and learning.

In this study, members of the international collaborative research team taught forms of tool use and food extraction techniques to high-ranking individuals in four different captive chimpanzee communities. Scientists then observed as those individuals passed on the techniques to other members of their communities. The scientists included Frans de Waal, PhD, Victoria Horner, PhD, and Kristin Bonnie from the Yerkes Research Center, lead scientists Andrew Whiten, PhD, and Antoine Spireti from St. Andrews University, and Susan Lambeth, PhD, and Steven Schapiro, PhD, from the University of Texas......... Posted by: Kelly      Read more         Source