Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Finding hidden invaders in a Hawaiian rain forest

08.03.2005


By applying novel measurement techniques from a high-altitude aircraft, scientists detected two species of invading plants that are changing the ecology of rain forest near the Kilauea Volcano in the Hawaii Volcanoes National Park. Lead author, Dr. Gregory Asner of the Carnegie Institution’s Department of Global Ecology, explained: "We found chemical fingerprints from the plant leaves and used them to tell which species dominated specific areas. We employed the recently upgraded NASA Airborne Visible and Infrared Imaging Spectrometer (AVIRIS) to measure leaf nitrogen and water content from the aircraft, and corroborated the data on the ground. The fingerprints showed where the native dominant tree ’ohia’ (Metrosideros polymorpha) has been taken over by the invading Canary Islands tree, Myrica faya, and more importantly identified areas where Myrica invasion is in its early stages. The aircraft imagery also showed us how the forest canopy chemistry is changing as a result of the invader." The study is published in the March 7-11, 2005, early online edition of the Proceedings of the National Academy of Sciences.


Traditional remote sensing of the forest canopy is shown at on the bottom. The middle and top images are the outputs from the new analytical techniques used in the study. They show canopy water content and leaf nitrogen concentration from high-altitude airborne imaging spectroscopy. (Image courtesy Gregory Asner.)



The new methods are exciting because they detect effects of biological invasions on ecosystems, not just the presence of an invader. Islands like Hawaii are vulnerable to biological invasion; new species can wreak havoc very quickly. The fact that the new techniques allowed the scientists to detect an invader before it dominated the landscape is important to future management strategies. As a result of the findings, the group has expanded to include collaborators from federal, state, and private organizations. Scientists and resource managers from Carnegie, Stanford University, the U.S. National Park Service, NASA, and The Nature Conservancy have teamed up with an unprecedented plan to map the chemical and structural composition of Hawaiian ecosystems and to find invasive species and track their ecological impacts. This month, Carnegie global ecologists and engineers from the NASA Jet Propulsion Laboratory are flying an upgraded version of the AVIRIS airborne spectrometer on a more nimble Twin Otter turboprop aircraft, not only to find invasive species, but to develop the next generation of ecosystem monitoring capabilities.

On Kilauea Volcano, the native Metrosideros tree typically has a low concentration of nitrogen in its leaves ( .6% to .8%), while the invading Canary Islands tree has relatively high nitrogen concentration (1.5% to 1.8%), because it can acquire nitrogen from the atmosphere.


"The high leaf nitrogen associated with the invading tree means that it is basically fertilizing the forest with more nitrogen," commented Asner. "The leaves turn over faster and there is more nitrogen in the soil. However, the invader shades out nearly all other species, so this excess nitrogen is not available to other species. Although we don’t know exactly what the domino effects of this invasion will be, we are in a good position to predict them as we learn more about the chemical changes the forest is undergoing."

The scientists also had a big surprise using the new aircraft-based techniques: they located another invader, the Kahili ginger plant (Hedychium gardnerianum), growing under the forest canopy. Ginger cannot be detected from above the forest canopy using traditional aircraft or satellite approaches, but the new methods are sensitive to its high water content. In addition, the aircraft-based analysis discovered that ginger reduces the amount of nitrogen in the Metrosideros forest canopy--a discovery that was later corroborated by ground-based sampling.

Peter Vitousek from Stanford University, who coauthored the paper, commented: "This is the first time where remote sensing showed me something new concerning how an ecosystem works. Up to this point, remote sensing has been invaluable for understanding how features or processes that have been observed in one or a few places are distributed in space and time. These new methods discovered a consequence of biological invasion that had not been detected before AND showed how it varies across the landscape."

"These findings are valuable to resource managers on two levels," remarked Tim Tunison, Chief of Resource Management of the Hawaii Volcanoes National Park. "We need to understand the ecological effects of invasions over the landscape to develop effective control strategies, and the Asner/Vitousek work gives us valuable insights about this problem. On a more practical level we need to know the distribution of invasives. Weeds are often difficult to find in dense, wet forest in Hawaii. This study has helped us with a particularly difficult-to-map species with confusing signatures, Myrica faya. This is the first time in my experience that remote sensing has detected an understory species, kahili ginger, one of the most disruptive weeds in Hawaiian rain forests."

Asner commented on the expanded effort with the multi-institutional team: "Because Hawaii contains so many different types of ecosystems, from desert grasslands to tropical rain forests, Carnegie’s ecological remote sensing program has focused on the area as the ideal outdoor research laboratory for devising the next generation of aircraft and spacecraft observations. Now we’ve added a major focus on the application of our techniques to invasive species problems in the Hawaiian Islands. It is a win-win combination for all involved."

Dr. Gregory Asner | EurekAlert!
Further information:
http://www.CarnegieInstitution.org

More articles from Ecology, The Environment and Conservation:

nachricht Bioinvasion on the rise
15.02.2017 | Universität Konstanz

nachricht Litter Levels in the Depths of the Arctic are On the Rise
10.02.2017 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung

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: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Stingless bees have their nests protected by soldiers

24.02.2017 | Life Sciences

New risk factors for anxiety disorders

24.02.2017 | Life Sciences

MWC 2017: 5G Capital Berlin

24.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>