Friday, October 18, 2013

Australian climate change researchers look to penguin poo

Climate change -- October 15, 2013

By: News Desk

If you're going to study the effects of climate change on a food chain, you have to look at how that food, ahem, ends up. Researchers from the Australian government's Antarctic Division will study the Antarctic food chain, specifically, the historical feeding habits of Adelie penguins and impacts of ocean acidification on phytoplankton and bacteria, the smallest building blocks of the southern continent's ecosystem, according to a report from AFP.

Seabird expert Barbara Wienecke will lead the survey as the team excavates ancient droppings to dertermine changes in the penguins' diets over time.

She explained the research to AFP:
"We will be digging down into the old soils formed from bird waste and looking for the remains of prey, such as fish ear-bones and squid beaks," said Wienecke.
"It is the first time this type of work has been done in the Davis region and we are hopeful of finding out whether Adelie diets changed in the past, for example, from krill to fish-based diets," she added.
"Gaining this knowledge can help manage Southern Ocean fisheries to avoid disrupting the Antarctic food chain."


Thursday, October 10, 2013

Longer Life for Humans Linked to Further Loss of Endangered Species

Endangered yellow eyed penguin. New Zealand has a high percentage of endangered birds. (Credit: © paradoxdes / Fotolia)
Oct. 9, 2013 — As human life expectancy increases, so does the percentage of invasive and endangered birds and mammals, according to a new study by the University of California, Davis.

The study, published in the September issue of Ecology and Society, examined a combination of 15 social and ecological variables -- from tourism and per capita gross domestic product to water stress and political stability. Then researchers analyzed their correlations with invasive and endangered birds and mammals, which are two indicators of what conservationist Aldo Leopold termed "land sickness," the study said.

Human life expectancy, which is rarely included among indexes that examine human impacts on the environment, surfaced as the key predictor of global invasions and extinctions.

"It's not a random pattern," said lead author Aaron Lotz, a postdoctoral scholar in the Department of Wildlife, Fish and Conservation Biology when the study was conducted. "Out of all this data, that one factor -- human life expectancy -- was the determining factor for endangered and invasive birds and mammals."

The study analyzed data from 100 countries, which included roughly 87 percent of the world's population, 43 percent of global GDP per capita, and covered 74 percent of Earth's total land area.

Additional factors considered were agricultural intensity, rainfall, pesticide regulation, energy efficiency, wilderness protection, latitude, export-import ratio, undernourishment, adult literacy, female participation in government, and total population.
The findings include:
  • New Zealand, the United States and the Philippines had among the highest percentages of endangered and invasive birds.
  • New Zealand had the highest percentage of all endangered and invasive species combined, largely due to its lack of native terrestrial mammals. The study said that in the past 700 to 800 years since the country was colonized, it has experienced massive invasion by nonindigenous species, resulting in catastrophic biodiversity loss.
  • African countries had the lowest percentage of invasive and endangered birds and mammals. These countries have had very little international trade, which limits opportunities for biological invasion.
  • As GDP per capita -- a standard measure of affluence -- increased in a country, so did the percentage of invasive birds and mammals.
  • As total biodiversity and total land area increased in a country, so did the percentage of endangered birds. (Biodiversity in this context is not a measure of health but refers to the number of species in an area.)
Lotz said the study's results indicate the need for a better scientific understanding of the complex interactions among humans and their environment.

"Some studies have this view that there's wildlife and then there's us," said Lotz. "But we're part of the ecosystem. We need to start relating humans to the environment in our research and not leave them out of the equation. We need to realize we have a direct link to nature."

Story Source:
The above story is based on materials provided by University of California - Davis.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:
  1. Aaron Lotz, Craig R. Allen. Social-Ecological Predictors of Global Invasions and Extinctions. Ecology and Society, 2013; 18 (3) DOI: 10.5751/ES-05550-180315
University of California - Davis (2013, October 9). Longer life for humans linked to further loss of endangered species. ScienceDaily. Retrieved October 10, 2013, from­ /releases/2013/10/131009130122.htm

Wednesday, October 9, 2013

An ancient dinosaur-era bird turns out to have two tails

A prehistoric bird with two tails.
A reconstruction of a two-tailed 120-million-year-old Jeholornis.
Illustration courtesy Aijuan Shi
Dan Vergano
National Geographic
Published October 7, 2013

The early bird gets two tails? A 120-million-year-old bird sported a long tail and a second, unexpected tail frond, paleontologists suggest. The discovery points to a complicated evolutionary path for the tails we see in birds today.

One of the oldest known birds, Jeholornis, lived in what is today China, along with a trove of other feathered dinosaurs discovered in the region over the last decade. It was also thought to sport only a long fan-feathered tail at its back end. Now, however, paleontologists are claiming discovery of a second tail frond adorning the bird.

"The 'two-tail' plumage of Jeholornis is unique," according to the study, which was led by Jingmai O’Connor of the Chinese Academy of Sciences in Beijing. The report of the discovery of the tail frond was published in the Proceedings of the National Academy of Sciences.

Of 11 Jeholornis fossils that retain evidence of ancient plumage, 6 have signs of this frond of 11 feathers, which would have jutted above the bird's back at a jaunty, upright angle in a "visually striking" manner, according to the study.

Two-Tailed Display

"Clearly the display aspect of the frond would have been undeniable," says paleontologist Mark Norell, of the American Museum of Natural History in New York, who was not part of the study. "It calls to mind living birds, even peacocks, which display broad plumes of feathers."
In peacocks and other birds, such feathery features are more for attracting the attention of potential mates than for any functional purpose.

Since male birds today are the ones with the striking plumage, the authors suggest that perhaps only one sex of Jeholornis sported the eye-catching tail fronds.

Early Aviation Advantage?

Jeholornis is not thought to be directly related to modern birds, which seem to have evolved from a different line of early avians. The study authors suggest that the tail frond may have played a stabilizing role in the flight of these early birds and that if the arrangement of feathers had proven advantageous enough, modern birds might have evolved to sport such two-tailed features. They see the fronds as flattening to offer a streamlined appearance when the bird was in flight.

Other researchers aren't convinced the newly discovered tail frond played much of a role in aviation, however. "Feathering in the new specimens is quite interesting, but we have to remember it is a feature so far only known in one species," says University of Texas paleontologist Julia Clarke, who adds the frond wasn't seen in all the fossils.

"Thus, its implications for the origin of flight are unclear," she says. "It could have been a peculiarity of the one species, as the authors note." Perhaps more likely, she suggests the frond simply evolved as an easy-to-notice "sexual display" flaunted by these early birds.