Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Study may help predict extinction tipping point for species

09.09.2010
What if there were a way to predict when a species was about to become extinct—in time to do something about it?

Findings from a study by John M. Drake, associate professor in the University of Georgia Odum School of Ecology, and Blaine D. Griffen, assistant professor at the University of South Carolina, may eventually lead to such an outcome—and that is only the start. Their study also has implications for understanding drastic, even catastrophic, changes in many other kinds of complex systems, from the human brain to entire ecosystems.

The paper, "Early warning signals of extinction in deteriorating environments," published in the early online edition of the journal Nature, describes a study of the fluctuations in experimental populations of water fleas (Daphnia magna) undergoing environmental stress until they reach a tipping point beyond which they do not remain viable. The study is unique in its careful comparison of these stressed populations with other, healthy populations in the context of new theories about dynamic systems undergoing transitions at a tipping point, particularly a phenomenon known as "critical slowing down."

"This is the first experimental demonstration of critical slowing down in a biological system," said Drake. He explained that critical slowing down is a term used to describe a pattern in data that has previously been observed in physics and the Earth sciences, but until now has been only a theoretical possibility in biology. It describes the decreasing rate of recovery from small disturbances to a system as it approaches a tipping point. When a system is close to a tipping point, it can take a long time to recover from even a very small disturbance. "The theory was originally used to describe drastic changes in other kinds of systems—everything from epileptic seizures to regime shifts in the earth's climate system," Drake said. "But these attributions of CSD primarily have been after-the-fact explanations of anomalous observations without clear controls."

This also is the first time the theory has been applied to extinction.

The experiment featured populations of water fleas that were assigned to either deteriorating environments (in this case, declining levels of food) or stable environments (the control group). The experiment lasted for 416 days, when the last population in the deteriorating environment group became extinct. Depending upon the amount of food they received, populations in the deteriorating environment group reached the population viability tipping point after approximately 300 days. Populations in the control group never reached it; those populations persisted.

The researchers next looked at a variety of statistical indicators, early warning signals that could detect the onset of CSD and thereby predict the approach to a tipping point. They compared the indicators with the timing of the decrease in food and with the achievement of the tipping point, mathematically referred to as a "transcritical bifurcation." They found that each of the indicators—some more strongly than others—showed evidence of the approaching tipping point well before it was reached.

According to Drake, what is even more important is the generality such statistical indicators are expected to exhibit. That is, although precise quantitative models are required to predict most natural phenomena—in any domain of science—with any degree of accuracy, the theory of critical slowing down applies qualitatively anytime a bifurcation is in the vicinity. "You don't have to know the underlying equations to use the theory," Drake said, "and this is important in biology, where the dynamics are typically sufficiently complex that we often do not know which equations to use. In fact, we may never come to such a complete understanding, given the range of biodiversity out there and the fact that species are evolving all the time."

Drake pointed out that potential applications, such as predicting extinctions based on evidence of CSD, are still in the future. "This is the first step in the fundamental research that would underlie such an application," he said. "We have shown that CSD can happen in populations—that is all. The real world is a lot 'noisier' than the lab. Using early warning signals to predict approaching tipping points could eventually be a powerful tool for conservation planning, though, and for better understanding a host of other kinds of systems as well."

John Gittleman, dean of the Odum School of Ecology, agreed. "This study fits into one of the core missions of the Odum School by developing a predictive science of ecology," he said. "We now have clear, predictive research programs dealing with extinction, conservation, and disease, all critically important areas for a more robust science of ecology."

John M. Drake | EurekAlert!
Further information:
http://www.uga.edu

Further reports about: Biodiversity CSD Ecology Odum science of ecology water fleas

More articles from Studies and Analyses:

nachricht Smart Data Transformation – Surfing the Big Wave
02.12.2016 | Fraunhofer-Institut für Angewandte Informationstechnik FIT

nachricht Climate change could outpace EPA Lake Champlain protections
18.11.2016 | University of Vermont

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

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

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>