Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Invading trees put rainforests at risk

04.03.2008
To the list of threats to tropical rainforests you can add a new one — trees.

It might seem that for a rainforest the more trees the merrier, but a new study by scientists at the Carnegie Institution warns that non-native trees invading a rainforest can change its basic ecological structure — rendering it less hospitable to the myriad plant and animal species that depend on its resources. Results are published in the Proceedings of the National Academy of Sciences.*

The research team, led by Gregory Asner of the Carnegie Institution’s Department of Global Ecology, used innovative remote sensing technology on aircraft to survey the impact of invasives on more than 220,000 hectares (850 square miles) of rainforest on the island of Hawaii. Previous studies of the impact of invasive plants on forests were limited to small areas. Instruments aboard the Carnegie Airborne Observatory (CAO) penetrate the forest canopy to create a regional “CAT scan” of the ecosystem, identifying key plant species and mapping the forest’s three-dimensional structure.

“Invasive tree species often show biochemical, physiological, and structural properties that are different from native species,” says Asner. “We can use these ‘fingerprints’ combined with the 3-D images to see how the invasives are changing the forest.”

This is the first use of this approach to track invasives in Hawaii, where roughly half of all organisms are non-native, and approximately 120 plant species are considered highly invasive. Undisturbed Hawaiian rainforests are often dominated by the ohia tree (Metrosideros polymorpha), but these slow-growing native trees are losing ground to newcomers, such as the tropical ash (Fraxinus uhdei) and the Canary Island fire tree (Morella faya).

CAO surveys of rainforest tracts on the Mauna Kea and Kilauea Volcanoes found that stands of these two invasive tree species form significantly denser canopies than the native ohia trees. Less light reaches lower forest levels, and as a result native understory plants such as tree ferns are suppressed.

Introduced trees can also pave the way for more invaders by altering soil fertility. The Moluccan albizia (Falcataria moluccana) “fixes” atmospheric nitrogen, concentrating it in the soil, which speeds the growth of a smaller invasive tree, the Strawberry Guava (Psidium cattleianum). The guava trees form a dense, mid-level thicket that blocks most light from reaching the ground and stifles young native plants.

“All of our invasive species detections were made in protected state and federal rainforest reserves,” says Asner. “These species can spread across protected areas without the help of land use changes or other human activities, suggesting that traditional conservation approaches on the ground aren’t enough for the long-term survival of Hawaii’s rainforests.”

“These new airborne technologies, which are sensitive enough to discern saplings and young trees, may make the problem more tractable,”comments study co-author Flint Hughes of the US Forest Service. “They allow scientists to probe the make-up of forests over large areas and detect invasions at earlier stages.”

Based on the success of this study, Asner and colleagues plan to expand CAO surveys of the ecological impacts of invaders in other forests on Hawaii and Kauai Islands, where premier, remote rainforest reserves remain virtually unmapped.

Gregory Asner | EurekAlert!
Further information:
http://www.CIW.edu

More articles from Ecology, The Environment and Conservation:

nachricht Dispersal of Fish Eggs by Water Birds – Just a Myth?
19.02.2018 | Universität Basel

nachricht Removing fossil fuel subsidies will not reduce CO2 emissions as much as hoped
08.02.2018 | International Institute for Applied Systems Analysis (IIASA)

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: BAM@Hannover Messe: innovative 3D printing method for space flight

At the Hannover Messe 2018, the Bundesanstalt für Materialforschung und-prüfung (BAM) will show how, in the future, astronauts could produce their own tools or spare parts in zero gravity using 3D printing. This will reduce, weight and transport costs for space missions. Visitors can experience the innovative additive manufacturing process live at the fair.

Powder-based additive manufacturing in zero gravity is the name of the project in which a component is produced by applying metallic powder layers and then...

Im Focus: Molecules Brilliantly Illuminated

Physicists at the Laboratory for Attosecond Physics, which is jointly run by Ludwig-Maximilians-Universität and the Max Planck Institute of Quantum Optics, have developed a high-power laser system that generates ultrashort pulses of light covering a large share of the mid-infrared spectrum. The researchers envisage a wide range of applications for the technology – in the early diagnosis of cancer, for instance.

Molecules are the building blocks of life. Like all other organisms, we are made of them. They control our biorhythm, and they can also reflect our state of...

Im Focus: Spider silk key to new bone-fixing composite

University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.

Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.

Im Focus: Writing and deleting magnets with lasers

Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.

Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...

Im Focus: Gamma-ray flashes from plasma filaments

Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.

The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

IWOLIA: A conference bringing together German Industrie 4.0 and French Industrie du Futur

09.04.2018 | Event News

 
Latest News

Getting electrons to move in a semiconductor

25.04.2018 | Physics and Astronomy

Reconstructing what makes us tick

25.04.2018 | Physics and Astronomy

Cheap 3-D printer can produce self-folding materials

25.04.2018 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>