Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Down by the river

29.01.2003


As Rebecca Brown kayaked down the Nolichucky River in North Carolina one summer, she followed a path similar to many of her own study subjects. Seeds and other propagules often float downstream before settling along riverbanks. Rampant with change, these areas offer a nutrient-rich location for new plants, yet pose the danger of sweeping vegetation away in a flood. It is this high volatility that makes the area resource rich and perfect for invasive and native plants to put down their roots. In a study presented in January’s Ecology, researchers Rebecca Brown and Robert Peet found areas subject to frequent flooding also showed a higher number of invasive exotic plants than upland regions outside of floodplains.



Mild to low-intensity disturbances, such as a small flood from a rainstorm every year, or larger floods every few years, create space and make nutrients available, allowing new plants to grow. Scientists call this an immigration process. In contrast to extinction processes such as competition, extreme disturbances, and environmental stresses, the immigration process sets the stage for new life.

“Community composition is driven by immigration. Areas disturbed frequently, such as riversides and roadsides, are more receptive to propagules from native species and also prove to be just as hospitable for exotics,” said Brown.


Brown and Peet, along with a team of field assistants, traversed the countryside collecting data along rivers and uplands in the southern Appalachian forests of North Carolina to compare the relationship between exotic and native species richness. Combining information from the Carolina Vegetation Survey database and the United States Department of Agriculture Plants database, the duo studied riparian areas within 100-year flood zones and uplands outside of the floodplains. They also took into account differences in soil pH, geology, and other factors, recording both herbs and trees in almost 1200 plots.

The researchers found species diversity to be significantly higher for both native and exotic species in the riparian areas than in upland areas.

“Riparian areas have roughly 40 times greater mean exotic species per plot then upland areas,” said Brown.

Even when examining areas with comparable amounts of light availability and soil fertility the results remained fairly similar. As flood frequency decreased, the number of exotic species decreased. But species richness -- the variety of species -- for native and exotics also decreased. According to the researchers these results may be a combination of fewer seeds and less disturbances, leading to fewer opportunities for exotics to invade the upland sites.

Brown and Peet also looked at the results in terms of scale.

Previous research suggests that high species diversity should reduce invasibility because the more species compete in an area, the fewer resources are available to incoming species. Brown and Peet’s study validated this concept at the small scale. However it did not hold true when they compared diversity of exotic and native species in large scale areas. Brown explains why this is so:

“It is possible that we see this phenomenon only at small scales because plants compete at small scales, while at large scales, flooding, variations in seed supply, or variations in resource availability allow the immigration of all types of new species, native and exotic, into the community.”


###
Ecology is a peer-reviewed journal published twelve times a year by the Ecological Society of America (ESA). Copies of the above article are available free of charge to the press through the Society’s Public Affairs Office. Members of the press may also obtain copies of ESA’s entire family of publications, which includes Ecology, Ecological Applications, and Ecological Monographs. Others interested in copies of articles should contact the Reprint Department at the address in the masthead.

Founded in 1915, the Ecological Society of America (ESA) is a scientific, non-profit, organization with over 7800 members. Through ESA reports, journals, membership research, and expert testimony to Congress, ESA seeks to promote the responsible application of ecological data and principles to the solution of environmental problems. For more information about the Society and its activities, access ESA’s web site at: http://www.esa.org.


Annie Drinkard | EurekAlert!
Further information:
http://www.esa.org/

More articles from Ecology, The Environment and Conservation:

nachricht Scientists team up on study to save endangered African penguins
16.11.2017 | Florida Atlantic University

nachricht Climate change: Urban trees are growing faster worldwide
13.11.2017 | Technische Universität München

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: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

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...

Im Focus: Visual intelligence is not the same as IQ

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...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

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....

Im Focus: Researchers Develop Data Bus for Quantum Computer

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,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Previous evidence of water on mars now identified as grainflows

21.11.2017 | Physics and Astronomy

NASA's James Webb Space Telescope completes final cryogenic testing

21.11.2017 | Physics and Astronomy

New catalyst controls activation of a carbon-hydrogen bond

21.11.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>