March 12, 2007, 9:11 PM CT

Disease opened door to invading species

Plant and animal diseases can play a major and poorly appreciated role in allowing the invasion of exotic species, which in turn often threatens biodiversity, ecological function and the world economy, scientists say in a new report.

In particular, a plant pathogen appears to have opened the gate for the successful invasion of non-native grasses into much of California, one of the world's largest documented cases of invading species and one that dramatically changed the history and ecology of a vast grassland ecosystem.

The study, published recently in Proceedings of the National Academy of Sciences, a professional journal, should improve the understanding of invasive species and possibly suggest new tools to combat them, said scientists at Oregon State University.

"Even if we can't control all the diseases that help species invade, at least now we know to consider diseases when studying invasion," said Elizabeth Borer, an assistant professor of zoology at OSU. "In analyzing the ecology of exotic plant or animal species, it's clear that diseases are one part of the equation".

About 50,000 exotic species have been introduced into the United States, and the havoc they wreak upon agricultural crops, wildlife, ranch animals, forests and grasslands costs about $137 billion a year, researchers say. Invading species are also responsible for about half of all native species that go extinct, studies show......... Posted by: Erica      Read more         Source

March 12, 2007, 9:06 PM CT

About Caribbean extinctions

Smithsonian researchers and his colleagues report a new study that may shake up the way paleontologists think about how environmental change shapes life on Earth. The scientists summarized the environmental, ecological and evolutionary consequences for Caribbean shallow-water marine communities when the Isthmus of Panama was formed. They concluded that extinctions resulting when one ocean became two were delayed by 2 million years.

Scientists from the Smithsonian Tropical Research Institute, Scripps Institution of Oceanography and London's Natural History Museum report their study in the Proceedings of the National Academy of Sciences on March 12.

Three to 4 million years ago, the Isthmus of Panama land bridge rose to connect North and South America, and divided one vast ocean into two. In response, a major extinction of marine animals that had flourished under open seaway conditions occurred on the Caribbean side of the new Isthmus.

"We may be way off-track when we search for the causes of extinctions by looking only at the time the extinctions occur in the fossil record, which is what paleontologists normally do," said Aaron O'Dea, postdoctoral fellow at the Smithsonian Tropical Research Institute and Scripps Institution of Oceanography. "In our case, we see that most coral and snail species died off a good 2 million years after the environmental change that caused their demise."........ Posted by: Kelly      Read more         Source

March 12, 2007, 8:58 PM CT

Lifting the Chinese tiger trade ban

WASHINGTONAny easing of the current Chinese ban on trading products made from tigers is likely a death sentence for the endangered cats, as per a new TRAFFIC report released recently by World Wildlife Fund and TRAFFICthe wildlife trade monitoring program of WWF and IUCN.

The report warns that Chinese business owners who would profit from the tiger trade are putting increasing pressure on the Chinese government to overturn its successful 1993 ban and allow domestic trade in captive-bred tiger parts for use in traditional medicine and clothing to resume. For example, investors in the growing number of large-scale captive-breeding "tiger farms" in China are pushing for legalizing trade of products from these facilities, which now house 4,000 tigers. The farms keep captive-bred tigers together in large enclosuresa condition not found in the wildand feed live animals to them before busloads of tourists. Such farmed tigers are unsuitable for reintroduction into the wild.

"Reopening any legal trade in tiger parts would be an enormous step backwards for tiger conservation," said Leigh Henry, Program Officer for TRAFFIC North America. "A legal market in China would muddy the waters for enforcement officials and provide smugglers with a convenient cover for laundering wild tigers since farmed and wild products are indistinguishable. Raising tigers in captivity is 250 times more expensive than poaching wild tigers so there's plenty of incentive to poach and smuggle the last remaining wild populations to extinction"......... Posted by: Kelly      Read more         Source

March 6, 2007, 3:38 PM CT

Amazonian Basin Not Well-Populated

There's a scholarly debate brewing about whether pre-Columbian Amazonian populations settled in large numbers across Amazonia and created the modern forest setting that many conservationists take to be 'natural.'.

This view has become fashionable among many archaeologists and anthropologists, and is challenged in a recent paper from Dr. Mark Bush of the Florida Institute of Technology. The findings of Bush's research may rekindle a debate has major implications for land use and policy-setting in the rain forest.

"We don't contradict that there were major settlements in key areas flanking the Amazon Channel -- there could have been millions of people living there," says Mark Bush, a British-born paleo-ecologist who travels to extremely remote rain forest locations to collect core samples from ancient lakes. He then analyzes those samples for pollen and charcoal and thus is able to conclude with a high degree of accuracy the extent of human settlement in that region.

"What we do say is that when you start to look away from known settlements, you may see very long-term local use," he says. "These people didn't stray very far from home, or from local bodies of water for several thousands of years. We looked at clusters of lakes and landscapes where people lived, and asked, did they leave their homesite to farm around other nearby lakes? No they didn't. These findings argue for a very localized use of Amazonian forest resources outside the main, known, archaeological areas"......... Posted by: Janet      Read more         Source

March 6, 2007, 4:52 AM CT

New View On Biology Of Flavonoids

Flavonoids, a group of compounds found in fruits and vegetables that had been thought to be nutritionally important for their antioxidant activity, actually have little or no value in that role, according to an analysis by scientists in the Linus Pauling Institute at Oregon State University.

However, these same compounds may indeed benefit human health, but for reasons that are quite different the body sees them as foreign compounds, researchers say, and through different mechanisms, they could play a role in preventing cancer or heart disease.

Based on this new view of how flavonoids work, a relatively modest intake of them the amount you might find in a healthy diet with five to nine servings of fruits and vegetables is sufficient. Large doses taken via dietary supplements might do no additional good; an apple a day may still be the best bet.

A research survey, and updated analysis of how flavonoids work and function in the human body, were recently published in Free Radical Biology and Medicine, a professional journal.

"What we now know is that flavonoids are highly metabolized, which alters their chemical structure and diminishes their ability to function as an antioxidant," said Balz Frei, professor and director of the Linus Pauling Institute. "The body sees them as foreign compounds and modifies them for rapid excretion in the urine and bile"......... Posted by: Erica      Read more         Source

March 6, 2007, 4:40 AM CT

Tundra disappearing at rapid rate

Forests of spruce trees and shrubs in parts of northern Canada are taking over what were once tundra landscapes--forcing out the species that lived there. This shift can happen at a much faster speed than researchers originally thought, as per a new University of Alberta study that adds to the growing body of evidence on the effects of climate change.

The boundary, or treeline, between forest and tundra ecosystems is a prominent landscape feature in both Arctic and mountain environments. As global temperatures continue to increase, the treeline is expected to advance but the new research shows that this shift will not always occur gradually but can surge ahead.

"The conventional thinking on treeline dynamics has been that advances are very slow because conditions are so harsh at these high latitudes and altitudes," said Dr. Ryan Danby, from the Department of Biological Sciences. "But what our data indicates is that there was an upslope surge of trees in response to warmer temperatures. Its like it waited until conditions were just right and then it decided to get up and run, not just walk".

Danby and Dr. David Hik, also from the Faculty of Science, reconstructed changes in the density and altitude of treeline forests in southwestern Yukon over the past 300 years. Using tree rings, they were able to date the year of establishment and death of spruce trees and reconstruct changes in treeline vegetation. The study is reported in the "Journal of Ecology"......... Posted by: Janet      Read more         Source

March 5, 2007, 10:05 PM CT

How buddies help alpha males get the girl

Why do some individuals sacrifice their own self-interest to help others? The evolution and maintenance of cooperative behavior is a classic puzzle in evolutionary biology. In some animal societies, cooperation occurs in close-knit family groups and kin selection explains apparently selfless behavior. Not so for the lance-tailed manakin. Males of this little tropical bird cooperate in spectacular courtship displays with unrelated partners, and the benefits of lending a helping wing may only come years down the line. Instead of fighting over females, pairs of male lance-tailed manakins team up to court prospective mates. Two males dance together for interested females, using tightly synchronized 'leapfrog' and flight displays to impress the opposite sex. But when the dance is over, only the dominant male, the alpha, gets the chance to mate. Emily DuVal, of UC Berkeley's Museum of Vertebrate Zoology, studied these birds to answer the question of why subordinate beta males cooperate. Starting in 1999, DuVal color-banded and observed wild lance-tailed manakins in Panam to follow changes in status over multiple years. Then she used genetic analyses to determine chicks' paternity and genetic relationships among adults.

The results of DuVal's work, would be reported in the recent issue of The American Naturalist, showed that male partners were unrelated, and betas rarely sired chicks, ruling out two of the major hypotheses explaining males' cooperative behavior. Following males across years showed that betas became alphas more often than other males, but not necessarily at the same territory where they were betas. Even when the local alpha slot was empty, some betas moved to be helpers elsewhere rather than take over the vacant position. "Without being an alpha, there's essentially no chance for these males to reproduce," says DuVal. "My results suggest that betas could actually benefit from staying betas for a while, for example by gaining courtship skills during a sort of apprenticeship or by forming alliances with other males who later act as their betas." These results contrast with those from studies of other birds with cooperative courtship displays: wild turkeys strut cooperatively with close relatives, and ruffs (a shorebird) form alliances of males that often both mate while they are partners. These contrasts are interesting because they show that similar behavior can result from very different social and selective environments. DuVal is now a postdoctoral researcher at the Max Planck Institute for Ornithology, Gera number of, where she is investigating how female lance-tailed manakins choose their mates......... Posted by: Kelly      Read more         Source

March 5, 2007, 9:54 PM CT

Migration Of Avian Flu Virus

UC Irvine scientists have combined genetic and geographic data of the H5N1 avian flu virus to reconstruct its history over the past decade. They observed that multiple strains of the virus originated in the Chinese province of Guangdong, and they identified a number of of the migration routes through which the strains spread regionally and internationally.

By knowing where H5N1 strains develop and migrate, health officials can better limit the spread of the virus by strategically intervening. Local vaccinations can be better administered by using strains from regions that have repeatedly contributed to infections.

"If you can control the virus at its source, you can control it more efficiently," said Walter Fitch, professor of ecology and evolutionary biology in the School of Biological Sciences at UCI and co-author of the study. "With a road map of where the strain has migrated, you're more likely to isolate the strain that you should be using to make the vaccine".

The study appears this week in the online early edition of the Proceedings of the National Academy of Sciences.

This research offers the first statistical analysis detailing the geographic distribution of influenza A H5N1, the bird flu strain. While prior work informally identified H5N1 strains by location, the UCI analysis is the first to systematically track the migration of H5N1 through its evolutionary history, adding new details that identify the relative importance of the geographic and evolutionary advances the virus makes......... Posted by: Kelly      Read more         Source

March 5, 2007, 8:41 PM CT

Scientists Expand Microbe "Gene Language"

An international group of researchers has expanded the universal language for the genes of both disease-causing and beneficial microbes and their hosts. This expanded "lingua franca," called The Gene Ontology (GO), gives scientists a common set of terms to describe the interactions between a microbe and its host.

The Plant-Associated Microbe Gene Ontology (PAMGO) consortium and the GO consortium staff at the European Bioinformatics Institute approved and released more than 450 new terms for describing gene products involved in microbe-host interactions.

The National Science Foundation (NSF) and the USDA's Cooperative State Research, Education and Extension Service (CSREES) support the PAMGO project through grants from their joint Microbial Genome Sequencing program.

This new "common terminology" will speed development of new technologies for preventing infections by disease-causing microbes, while preserving or encouraging the presence of beneficial microbes. Researchers say the Gene Ontology will provide a powerful tool for comparing the functions of genes and proteins in a wide range of disease-related organisms.

"A common set of terms for exchange of information about microbe-host interactions will help scientists communicate information, and expand concepts from studies of microbes and their hosts," says Maryanna Henkart, director of NSF's Division of Molecular and Cellular Biology......... Posted by: Janet      Read more         Source

March 1, 2007, 10:00 PM CT

Evolutionary History Of Vespid Wasps

Researchers at the University of Illinois have conducted a genetic analysis of vespid wasps that revises the vespid family tree and challenges long-held views about how the wasps' social behaviors evolved. In the study, reported in the Feb. 21 Proceedings of the National Academy of Sciences, the scientists found genetic evidence that eusociality (the reproductive specialization seen in some insects and other animals) evolved independently in two groups of vespid wasps.

These findings contradict an earlier model of vespid wasp evolution, which placed the groups together in a single lineage with a common ancestor.

Eusocial behavior is quite rare, and generally involves the breeding of different reproductive classes within a colony. The sterile members of the group perform tasks that support their fertile counterparts. Eusociality occurs in only a few species of insects, rodents, crustaceans and other arthropods.

The evolution of eusociality in wasps has long been a source of debate, said U. of I. entomology graduate student Heather Hines and entomology professor Sydney Cameron, who is the principal investigator of the study. A previous model of vespid wasp evolution placed three subfamilies of wasps - the Polistinae, Vespinae and Stenogastrinae - together in a single evolutionary group with a common ancestor. This model did not rely on a genetic analysis of the wasps, but instead classified them as per several physical and behavioral traits......... Posted by: Kelly      Read more         Source