Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Report challenges common ecological hypothesis about species abundance

05.10.2006
A new report finds little empirical evidence to support a widely held ecological assumption that species are most abundant near the centers of their geographic ranges and decline in abundance near the ranges' edges.

"When we reviewed data from published studies that looked at species abundance at multiple sites across a range, we found almost no evidence that supported the so-called 'abundant-center hypothesis' and strong evidence that contradicted it," said Raphael D. Sagarin, associate director for oceans and coastal policy at Duke University's Nicholas Institute for Environmental Policy Solutions.

"This is troubling," Sagarin said, "because a lot of current thinking on ecological and evolutionary issues -- including how species will respond to climate change, how to identify probable locations of pest outbreaks, how genetic diversity is distributed among populations and where to locate habitat preserves -- has been based on the hypothesis."

The validity of these ideas now needs to be re-examined using empirical studies, he said.

Sagarin is one of the principal authors of the report, which appeared in the September 2006 issue of the journal Trends in Ecology and Evolution. Other authors are Steven D. Gaines of the University of California-Santa Barbara's Marine Science Institute and Department of Ecology, Evolution and Marine Biology; and Brian Gaylord of the University of California-Davis's Bodega Marine Laboratory and Section of Evolution and Ecology.

For their analysis, the authors reviewed not only published studies but also some new sets of data that they had compiled from field observations in a number of coastal locations of such invertebrate species as sea urchins, sea anemones and snails. They found that most of the studies showed that patterns of abundance were affected by a complex interplay of environmental, physical, biological, genetic and geographical factors that the abundant-center hypothesis failed to take into account.

Population clusters and high abundance sometimes occurred right at the geographic edges of the species' ranges, they found.

"Ecologists need to go back into the field and sample populations, taking advantage of new technologies that allow us to see what populations are actually like on scales not previously possible," Sagarin said. "In some way, it's a return to old-school ecology, but armed with high-tech tools we didn't have 30 years ago."

Advances in remote sensing, biophysical monitoring, ecological physiology, molecular genetics and genomics are rapidly enhancing scientists' ability to identify population and individual patterns across large spatial scales, he said. Scientists can collect data on such factors as growth rates, genetics, climate, human-caused impacts and species interactions in different parts of a population's range, and then look at the overlay of these variables and see the larger story, rather than making a simplifying assumption based on one variable.

"Theory and experimentation have their place," Sagarin said. "They can play important roles in helping us predict, in general, future changes in species' ranges due to climate change. But you need empirical field-based data to know, more specifically, how this is going to look on the ground. When a range shifts, is it going to look like the gradual arrival of a new species, or like an actual invasion? Theory alone can't tell us that."

Tim Lucas | EurekAlert!
Further information:
http://www.duke.edu

More articles from Ecology, The Environment and Conservation:

nachricht Scientists on the road to discovering impact of urban road dust
18.01.2018 | University of Alberta

nachricht Gran Chaco: Biodiversity at High Risk
17.01.2018 | Humboldt-Universität zu Berlin

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: Artificial agent designs quantum experiments

On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.

We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

Im Focus: Room-temperature multiferroic thin films and their properties

Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.

Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

 
Latest News

Let the good tubes roll

19.01.2018 | Materials Sciences

How cancer metastasis happens: Researchers reveal a key mechanism

19.01.2018 | Health and Medicine

Meteoritic stardust unlocks timing of supernova dust formation

19.01.2018 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>