April 3, 2008, 8:38 PM CT

Asian waterbirds stage remarkable comeback

NEW YORK (April 3, 2008) As per a report released recently by the Wildlife Conservation Society (WCS), several species of rare waterbirds from Cambodias famed Tonle Sap region have staged remarkable comebacks, thanks to a project involving a single team of park rangers to provide 24-hour protection to breeding colonies. The project pioneered a novel approach: employing former hunters and egg collectors to protect and monitor the colonies, thereby guaranteeing the active involvement of local communities in the initiative.

The report suggests that some species, which include varieties of storks, pelicans, and ibises, have rebounded 20-fold since 2001, when WCS and the Ministry of Environment of the Royal Government of Cambodia established the conservation project. Before that time, rampant harvesting of both eggs and chicks had driven the colonies to the brink of local extinction.

"This is an amazing success story for the people and wildlife of Cambodia," said Colin Poole, Wildlife Conservation Society director for Asia Programs. "It also shows how important local people are in the conservation of wildlife in their own backyards".

Scientists first discovered the colonies in the mid 1990s in Prek Toal, an area within the massive Tonle Sapa seasonally flooded wetland critical to Cambodias people and wildlife. According WCS researchers, the colonies include the largest, and in some cases, the only breeding populations of seven Globally Threatened large waterbird species in Southeast Asia......... Posted by: Kelly      Read more         Source

April 3, 2008, 8:36 PM CT

Hatchery fish outnumber wild chinook salmon

A recent study indicates that wild salmon may account for just 10 percent of California's fall-run chinook salmon population, while the vast majority of the fish come from hatcheries. The findings are particularly troubling in light of the disastrous decline in the population this year, which will probably force the closure of the 2008 season for commercial and recreational salmon fishing.

The role of hatcheries in the management of salmon populations has been a contentious issue for a number of years. The new findings appear to support the idea that including artificially propagated fish in population estimates can mask declines in natural populations caused by a lack of suitable habitat.

"Our finding that 90 percent of the fish are from hatcheries surprised a lot of people," said Rachel Barnett-Johnson, a fisheries biologist with the Institute of Marine Sciences at the University of California, Santa Cruz.

Barnett-Johnson and her coworkers published their results in the December 2007 issue of the Canadian Journal of Fisheries and Aquatic Sciences. The main focus of the paper is the development of a new technique for distinguishing between wild and hatchery-raised salmon. The scientists validated the technique and used it to estimate the percentage of wild fish among the fall-run chinook salmon caught by commercial fishing boats along the central California coast in 2002......... Posted by: Kelly      Read more         Source

April 3, 2008, 8:32 PM CT

Genes key to hormone production in plants

Scientists at North Carolina State University have pinpointed a small group of genes responsible for telling plants when, where and how to produce a hormone that is key to their development. Their findings shed light on the ways in which hormone production in plants affects both a plants growth and its ability to adapt to changing environments.

Dr. Jose Alonso, assistant professor of genetics, and a team of geneticists and plant biologists from NC State, Gera number of and the Czech Republic conducted the research. Their findings appear in the April 4 edition of the journal Cell.

Plant growth and development are regulated by a small number of hormones, which plants combine in various ways so that they can adapt to and thrive in changing environmental conditions. Auxin and ethylene are two of the most important of these growth-regulating hormones.

Researchers had previously established that plants respond differently to ethylene depending upon the type of plant tissue it is applied to, the developmental stage of the plant, and the surrounding environmental conditions. They also knew that the presence of auxin, another key growth-regulator, often served as a trigger for a plant to produce more ethylene, but were unsure of the ways in which auxin was synthesized......... Posted by: Erica      Read more         Source

April 3, 2008, 8:04 PM CT

Role of bats in plant protection

Scientists at the Smithsonian Tropical Research Institute report that bats significantly reduce insect abundance and damage on plants. In a lowland tropical rainforest in Panama, bats can consume roughly twice as a number of plant-eating insects as do birds. This landmark study in the journal Science is the first to compare the ability of bats and birds to protect plants via insect predation in a natural forest ecosystem.

A prior study by the authors suggested that bats were underestimated predators of plant eating insects, based on video recordings of feeding events.

In the current study, Smithsonian short-term fellow Margareta Kalka, and co-authors Elisabeth Kalko, institute staff scientist and professor at the Institute of Experimental Ecology at the University of Ulm, and Smithsonian postdoctoral fellow Adam Smith, separated the insect-control effects of bats and birds by placing netting enclosures over five common tropical plant species only at night or only by day. Uncovered control plants accessed by both bats and birds lost merely 4.3 percent of their leaf area to insect herbivores. When only birds were excluded, plants lost 7.2 percent of their leaf area. When only bats were excluded, plants lost a striking 13.3 percent of their leaf area, demonstrating that in the tropical forest understory bats can be more effective pest control agents than birds......... Posted by: Kelly      Read more         Source

April 3, 2008, 7:39 PM CT

Are animals stuck in time?

Dog owners, who have noticed that their four-legged friend seem equally delighted to see them after five minutes away as five hours, may wonder if animals can tell when time passes. Newly published research from The University of Western Ontario may bring us closer to answering that very question.

The results of the research, entitled "Episodic-Like Memory in Rats: Is it Based on When or How Long Ago," appear in the current issue of the journal Science, which was released recently.

William Roberts and colleagues in Western's Psychology Department observed that rats are able to keep track of how much time has passed since they discovered a piece of cheese, be it a little or a lot, but they don't actually form memories of when the discovery occurred. That is, the rats can't place the memories in time.

The research team, led by Roberts, designed an experiment in which rats visited the 'arms' of a maze at different times of day. Some arms contained moderately desirable food pellets, and one arm contained a highly desirable piece of cheese. Rats were later returned to the maze with the cheese removed on certain trials and with the cheese replaced with a pellet on others.

All told, three groups of rats were tested in the research using three varying cues: when, how long ago or when plus how long ago......... Posted by: Kelly      Read more         Source

April 2, 2008, 10:19 PM CT

Will Avocados be Next?

Researchers with the USDA Forest Service Southern Research Station (SRS), Iowa State University, and the Florida Division of Forestry have provided the first description of a fungus responsible for the wilt of redbay trees along the coasts of South Carolina, Georgia, and Florida.

In the recent issue of Plant Disease, SRS plant pathologist Stephen Fraedrich and fellow scientists provide results from their assessment of the fungus, the beetle that carries it, and their combined effect on redbay and other members of the laurel family, including sassafras, spicebush, and avocado.

Extensive mortality of redbay, an attractive evergreen tree common along the coasts of the southeastern United States, has been observed in South Carolina and Georgia since 2003. Though the wilt was at first attributed to drought, the cause was soon found to be a fungal pathogen and the exotic redbay ambrosia beetle, Xyleborus glabratus, a native to Southeast Asia that was first found in the area in 2002. A number of ambrosia beetles carry species of fungi as food for their larvae; a previously undescribed fungus in the genus Raffaelea is a fungal symbiont of this ambrosia beetle.

To determine if the fungus was the cause of the wilt, Fraedrich and colleagues inoculated redbay trees and containerized seedlings with the Raffaelea fungus; the plants died within 5 to 12 weeks. To connect fungus and beetle, they also exposed redbay seedlings to X. glabratus beetles; the ambrosia beetles tunneled into almost all of the plants, causing 70 percent of them to die. The scientists found the fungus in 91 percent of the beetle-attacked plants......... Posted by: Erica      Read more         Source

April 2, 2008, 10:05 PM CT

Gypsy Moth Management Made More Efficient

A computer model that provides land managers with a more efficient and cost-effective approach for controlling gypsy moths and other invasive pests has been created by biologists at Penn State University and the University of Cambridge in the United Kingdom. Gypsy moths, which were introduced to North America in the late 1860s, are responsible for the defoliation of over a million acres of forest land each year and the loss of tens of millions of dollars. In a paper would be published later this month (April 2008) in the journal Ecological Applications, the team's results indicate that the best strategies for managing the destructive pests include eradicating medium-density infestations and reducing high-density infestations, rather than reducing spreading from the main infestation.

"Our model is state dependent, which means that it recommends different management strategies depending on the situation," said Katriona Shea, Penn State associate professor of biology and the team's leader. "Most managers currently use the same strategy in all situations, but our model suggests that by tailoring their approach to a particular situation, managers can be more effective in slowing the spread of invasive species".

Saving time and money is of the utmost importance with gypsy moths, which have by now spread throughout the northeastern United States and into the Midwest. "Some people argue that it's just a matter of time before the moths spread across the entire United States, so why bother trying to slow them down?" said Shea. "But we see it differently. We hope that by slowing their spread we can buy some time to find a better way to deal with them"......... Posted by: Kelly      Read more         Source

April 2, 2008, 10:01 PM CT

New fish has a face even Dale Chihuly could love

A fish that would rather crawl into crevices than swim, and that may be able to see in the same way that humans do, could represent an entirely unknown family of fishes, says a University of Washington fish expert.

The fish, sighted in Indonesian waters off Ambon Island, has tan- and peach-colored zebra-striping, and rippling folds of skin that obscure its fins, making it look like a glass sculpture that Dale Chihuly might have dreamed up. But far from being hard and brittle like glass, the bodies of these fist-sized fish are soft and pliable enough to slip and slide into narrow crevices of coral reefs. Its probably part of the reason that they've typically gone unnoticed until now.

The individuals are undoubtedly anglerfishes, says Ted Pietsch, a UW professor of aquatic and fishery sciences who has published 150 scholarly articles and several books on anglerfishes and is the world's leading authority on them. In the last 50 years researchers have described only five new families of fishes and none of them were even remotely correlation to anglerfishes, Pietsch says.

Husband and wife Buck and Fitrie Randolph, with dive guide Toby Fadirsyair, found and photographed an individual Jan. 28 in Ambon harbor. A second adult has since been seen and two more small, and obviously juveniles were spotted March 26, off Ambon. One of the adults laid a mass of eggs, just spotted Tuesday......... Posted by: Kelly      Read more         Source

March 31, 2008, 9:13 PM CT

Pathway plants use to fight back against pathogens

Plants are not only smart, but they also wage a good fight, as per a University of Missouri biochemist. Prior studies have shown that plants can sense attacks by pathogens and activate their defenses. However, it has not been known what happens between the pathogen attacks and the defense activation, until now. A new MU study revealed a very complex process that explains how plants counter attack pathogens. This discovery could potentially lead to crops with enhanced disease resistance.

There is a chemical warfare between plants and pathogens, said Shuqun Zhang, associate professor of biochemistry in the College of Agriculture, Food and Natural Resources and the College of Medicine. Normally, plants put effort into growth and development. However, when plants sense pathogens, they have to use some of their energy and resources to make secondary metabolites to fight disease. Until now, very little has been known about how this process is regulated.

As per the study, plants first sense the attack of a pathogen, and then activate defense responses by triggering a complex signaling cascade in plants. One of the defense responses is the induction and accumulation of anti-microbial defense chemicals, known as phytoalexins.

In his study, Zhang found the specific signaling path, known as a mitogen-activated protein kinase (MAPK) cascade, in the plants that ends when the defense chemical camalexin is created. Camalexin is essential for resistance to some plant diseases. Zhang used Arabidopsis, a small flowering plant and the first to have its entire genome sequenced, and Botrytis cinera, a fungal pathogen that causes grey mold disease in many plants including grapes and strawberries......... Posted by: Erica      Read more         Source

March 31, 2008, 8:09 PM CT

Study questions 'cost of complexity' in evolution

New Haven, Conn. Higher organisms do not have a cost of complexity or slowdown in the evolution of complex traits as per a report by scientists at Yale and Washington University in Nature.

Biologists have long puzzled over the relationship between evolution of complex traits and the randomness of mutations in genes. Some have proposed that a cost of complexity makes it more difficult to evolve a complicated trait by random mutations, because effects of beneficial mutations are diluted.

While a mutation in a single gene can have effects on multiple traits, even as diverse as the structures of brain, kneecap and genitalia, we wondered how often random mutation would affect a number of traits said lead author Gunter Wagner, professor and chair of ecology and evolutionary biology at Yale. The phenomenon wherein mutation in a single gene can have effects on multiple traits is known as pleiotropy.

This study showed that most mutations only do affect few traits. Further, the effect of an individual mutation is not dampened because of its effects on other traits.

Observing 70 skeletal characteristics in the mouse, the scientists identified total of 102 genomic regions that affect the skeleton. They concluded that substitution in each genome segment affected a relatively small subset of characteristics and that the effect on each characteristic increased with the total number of traits affected......... Posted by: Janet      Read more         Source