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 Successful calculation of human and natural influence on cloud formation
04.11.2016 | Goethe-Universität Frankfurt am Main

nachricht Invasive Insects Cost the World Billions Per Year
04.10.2016 | University of Adelaide

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: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>