Stan Harpole, assistant professor of ecology, evolution and organismal biology at Iowa State University, is founding organizer of a team of more than 70 researchers working at 65 sites worldwide that tested that assumption.
They wanted to know if it is true that problematic invasive species often spread widely in their new habitats because they don’t encounter predators or diseases that help keep them in check in their home ranges.
“There is this assumption that when plants invade a new area that they become much more abundant in the new area than they were in the native areas,” said Harpole. “It turns out that, on average, they aren’t any more abundant away from home than they are at home.”
Harpole says there is a “rule of 10s” that can apply to invasive species.
“Of, say, 100 plants that arrive in a new area, only about 10 percent of those will survive without being in a greenhouse or some other controlled area,” said Harpole. “Of those 10 that can survive, only about 10 percent of those really cause problems.
“When you think about all the species we’ve brought over from other areas, relatively few have become serious pest species. The problem is we’ve brought over so many that quite a few have become major problems and they get a lot of attention.”
Harpole points to the kudzu plant as an example.
Kudzu was introduced from Asia as a soil erosion plant more than a century ago. It now chokes out native species from Texas to Maine to Florida, according to the U.S. Department of Agriculture.
Problem plants like this are uncommon when compared to all the exotic species in a region, but they do get the most interest and may give the impression that species that escape their home range often spread and take over new habitats and become more abundant than before, says Harpole.
Invasion can also be thought of more generally as a process in which new species enter new habitats. Even plants now considered native were once invaders, says Harpole.
When glaciers receded from the Midwest 10,000 years ago, there were no native species in the area – the retreating ice left bare ground open for invasion.
“All the plants that are now seen as native were invasive in the past in the sense that they had to spread across the landscape,” he said.
“What’s different today is that we move plants so much faster than they would move by themselves. Now a species can become global in a matter of years, where it may have taken tens of thousands of years in the past,” said Harpole.
Harpole is coauthor of a research paper led by Jennifer Firn of Queensland University of Technology, Australia, and is published in the journal Ecology Letters. Coordination of the study was funded by the National Science Foundation.
Stanley Harpole, Ecology Evolution and Organismal Biology, 515-294-7253, email@example.com
Stanley Harpole | Newswise Science News
Scientists team up on study to save endangered African penguins
16.11.2017 | Florida Atlantic University
Climate change: Urban trees are growing faster worldwide
13.11.2017 | Technische Universität München
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
17.11.2017 | Physics and Astronomy
17.11.2017 | Health and Medicine
17.11.2017 | Studies and Analyses