Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Extinction risk factors for New Zealand birds today differ from those of the past

03.08.2012
What makes some species more prone to extinction? A new study of nearly 300 species of New Zealand birds — from pre-human times to the present — reveals that the keys to survival today differ from those of the past.

The results are important in light of the growing number of studies that try to predict which species could be lost in the future based on what kinds of species are considered most threatened today, said lead author Lindell Bromham of Australian National University.

In the roughly 700 years since humans arrived in the remote islands that make up New Zealand, more than one out of four of New Zealand's native bird species have been wiped out.

Gone are birds such as the massive Haast's eagle, which weighed up to 33 pounds (15kg), and the giant moa, a flightless bird that stood up to ten feet (3m) tall.

Many species were hunted to extinction. Others were eaten by the animals humans brought with them — such as cats, rats and weasels — or pushed off their land as humans cleared and burned forests to make way for farms and pastures.

In a new study, a team of researchers examined whether biological traits such as body size might help scientists predict which species were likely to perish, and whether those risk factors held up over time.

To find out, they analyzed extinction patterns for New Zealand's native birds across four time periods in New Zealand's history, from pre-human times to the present. The data set included 274 species of living and extinct birds, such as ducks, penguins, geese, gulls, pigeons, parakeets and wrens.

The researchers looked for the biological traits that best predicted extinction risk in each time period. After accounting for similarities among closely related species, the researchers found that the traits that make some species more vulnerable today differ from what made species more prone to extinction in the past.

When the researchers compared the last 700 years of human occupation to pre-human times, for example, they found that flightless species such as moa and rails have been consistently hard-hit — presumably because species that can't fly make easy snacks.

"There was no difference in extinction risk between flightless and flighted species until humans arrived," said co-author Robert Lanfear, currently a visiting researcher at the U.S. National Evolutionary Synthesis Center.

Other risk factors for extinction changed with each new wave of human settlement.

In the period after Polynesians appeared until Europeans arrived in the 1820s, for example, bigger species were more likely to die out. According to one study the extinct giant moa — a group of ostrich-like birds that weighed up to 600 pounds (270 kg) — was hunted to extinction within less than one hundred years.

The researchers were surprised to find that after Europeans arrived, size was no longer a factor. Instead, species having males and females of different color were the hardest hit —possibly because those species were prized for museum collections.

Today, species that nest on the ground and lay only a few eggs at a time are considered most threatened, including the iconic kiwi, and a giant flightless parrot called the kakapo — two birds found only in New Zealand.

Why do the extinction risk factors for New Zealand birds living today differ from those of the past? Size, for example, was only associated with extinction risk in the period after Polynesians arrived but before European settlement.

"It could be that that's when birds were most heavily hunted for food," Bromham said. "Or it might be that all the largest birds went extinct soon after human arrival, so now there are no longer enough large species to spot the raised extinction risk!"

"If extinction has already caused the loss of a susceptible trait, then this trait may no longer be relevant to surviving species even though it is still the original cause of past extinctions. This is known as an 'extinction-filter'," explained co-author Phillip Cassey of the University of Adelaide in Australia.

For studies of extinction risk, the results mean we should proceed with caution when analyzing different time periods. "We can't guarantee that the patterns we detect in contemporary extinction risk are the same as those that have caused extinctions in the past, or will be the ones that are most important in the future," Bromham said.

Marcel Cardillo of Australian National University and Gillian Gibb of Massey University in New Zealand were also authors on this study.

The team's findings were published online on August 1, 2012 in the journal Proceedings of the Royal Society B.

CITATION: Bromham, L., R. Lanfear, et al. (2012). "Reconstructing past species assemblages reveals the changing patterns and drivers of extinction through time." Proceedings of the Royal Society B. http://dx.doi.org/10.1098/rspb.2012.1437.

The National Evolutionary Synthesis Center (NESCent) is a nonprofit science center dedicated to cross-disciplinary research in evolution. Funded by the U.S. National Science Foundation, NESCent is jointly operated by Duke University, The University of North Carolina at Chapel Hill, and North Carolina State University. For more information about research and training opportunities at NESCent, visit www.nescent.org.

Robin Ann Smith | EurekAlert!
Further information:
http://www.nescent.org

More articles from Ecology, The Environment and Conservation:

nachricht International network connects experimental research in European waters
21.03.2017 | Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB)

nachricht World Water Day 2017: It doesn’t Always Have to Be Drinking Water – Using Wastewater as a Resource
17.03.2017 | ISOE - Institut für sozial-ökologische Forschung

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Pulverizing electronic waste is green, clean -- and cold

22.03.2017 | Materials Sciences

Astronomers hazard a ride in a 'drifting carousel' to understand pulsating stars

22.03.2017 | Physics and Astronomy

New gel-like coating beefs up the performance of lithium-sulfur batteries

22.03.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>