Wildlife Disease News Digest

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Antarctic Penguins Reveal Steady DDT Levels
Discovery Channel - dsc.discovery.com
05 May 2008
J Marshall -- Map It
Area: Antarctica

Although use of the pesticide DDT was banned in the Northern Hemisphere in the 1970s, and DDT levels in the Arctic have declined steadily since then, new measurements show that DDT levels in Antarctic Adélie penguins have remained constant. "These levels are not high enough to be of concern," said lead researcher Heidi Geisz of the Virginia Institute of Marine Science in Gloucester Point, Va. But the presence of DDT suggests that other contaminants, some of which might have greater effects on seabirds, might be moving in the environment in similar ways, she added. The researchers blame melting glaciers for the continuing supply of DDT -- deposited in the ice in past decades -- to the environment, where it is taken up by phytoplankton and moves up the food chain, accumulating in the fat of animals at the top, such as Adélie penguins.

"There wasn't any DDT coming in on the air, or in the snow, or in the sea ice," Geisz said of other team members' environmental measurements, "but when they looked at the melt water, it was easily detectable there." The team measured DDT levels in the fat of 12 penguins they found dead and in 27 eggs found ruined at two study sites in the Antarctic. They compared these findings with measurements from the 1960s and 1970s and found no statistical change in the combined levels of DDT and its breakdown product, DDE. "It's not conclusive, given our sample size," Geisz noted, "but it appears that these levels aren't declining."

>>>FULL ARTICLE

New Reason For Bee Hive Collapse: Ecologists Tease Out Private Lives Of Plants And Their Pollinators
ScienceDaily - www.sciencedaily.com (Source: Wiley-Blackwell)
06 May 2008

The quality of pollen a plant produces is closely tied to its sexual habits, ecologists have discovered. As well as helping explain the evolution of such intimate relationships between plants and pollinators, the study -- one of the first of its kind and published online in the British Ecological Society's journal Functional Ecology -- also helps explain the recent dramatic decline in certain bumblebee species found in the shrinking areas of species-rich chalk grasslands and hay meadows across Northern Europe. Relationships between plants and pollinators have fascinated ecologists since Darwin's day. While ecologists have long known that pollinators such as honeybees and bumblebees are often faithful to certain flowers, and have done much work on the role of nectar as a food source, very little is known about how pollen quality affects these relationships.

Working on Salisbury Plain, the largest area of unimproved chalk grassland in north west Europe, ecologists from the universities of Plymouth, Stirling and Poitiers in France collected pollen from 23 different flowering plant species, 13 of which are only pollinated by insects while the other 10 species can either pollinate themselves or be insect pollinated. They analysed the pollen for protein content and, in the second part of the study, recorded bumblebee foraging behaviour. They found that without exception, plants that rely solely on insects for pollination produce the highest quality pollen, packing 65% more protein into their pollen than plant species that do not have to rely on insect pollinators. They also discovered that bumblebees prefer to visit plants with the most protein-rich pollen.

>>>FULL ARTICLE

Lost in migration: the perils of traversing a warming planet
Plenty Magazine - www.plentymag.com
06 May 2008
S Parsons
Illustration by Josh Cochran

Birds that navigate vast distances are especially vulnerable to climate change

Late last January, scientists in New Hampshire found something unusual on ice-covered Lake Winnipesaukee: seventeen frozen loons. Usually, changes in day length and temperature cue the threatened birds to leave in early January for their wintering grounds off the Atlantic coast; they return to the lake about four months later to breed. Biologists think unseasonably warm weather may have disrupted their migratory instincts, prompting them to linger on the lake. When conditions turned harsh mid-month, the birds were already molting new flying feathers, which usually happens after they migrate. Unable to fly away, they succumbed to the frigid conditions.

“It was very unexpected,” says Nick Rodenhouse, an ecologist at Wellesley College. “If warmer winters become more frequent, [loons] could die more often.” Scientists are unsure how much global warming had to do with the loons’ odd behavior, but they know that climate change will significantly affect birds. Some, like the migrating loons, will lose out; others could benefit. Among the winners may be residents—birds that stay put year round. At least one study suggests northeastern residents such as the tufted titmouse and northern cardinal might find more food as winter temperatures rise. But scientists predict rising temperatures may alter ecosystems, making habitat inhospitable and food scarce during breeding season.

>>>FULL ARTICLE

UCSB Researchers Focus on Animal-to-Human Disease Shifts
Santa Barbara Independent - www.independent.com
03 May 2008
B Licata
Area: United States

Say Urban Expansion Could Make Trend More Frequent

In recent years, infectious diseases has jumped from the animal kingdom onto human terrain with higher prevalence and lethal consequences, prompting the science world to investigate causes for this terrible outbreak. Emerging infectious diseases are those which occur in new populations or places, are reintroduced or newly introduced, or become highly virulent or resistant to certain treatments. Typically, emerging infectious diseases arise for multiple reasons, spanning from deforestation to human behavior, and entail certain harm for their host species, or the species which contains the infectious pathogen.

Jonathan Davies, a scientist at UCSB’s National Center for Ecological Analysis and Synthesis (NCEAS) and Amy Pederson, a research fellow at the University of Sheffield addressed the growing risk of emerging infectious disease in an analysis showing how both the proximity and similarities between species can determine the communicability of a pathogen between various hosts. “Infectious diseases crossing species barriers pose a huge and increasing threat to human health and the conservation of wild species,” said Davies. “The critical question we investigated is what determines the breadth of host species that a pathogen can infect.”

>>>FULL ARTICLE

Cited Journal Article
>>>Phylogeny and geography predict pathogen community similarity in wild primates and humans - Proc Biol Sci. 2008 Apr 29 [Epub ahead of print]

OTHER WILDLIFE HEALTH RELATED NEWS
Photo courtesy of Associated Press