Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Undisturbed Amazonian forests are changing, say scientists

11.03.2004


A research team of U.S. and Brazilian scientists has shown that rainforests in central Amazonia are experiencing striking changes in dynamics and species composition. Although the cause of these changes - in what are believed to be completely undisturbed, old-growth forests - is uncertain, a leading explanation is that they are being driven by rising levels of carbon dioxide in the atmosphere.



Carbon dioxide levels have risen by 30% in the last 200 years as a result of industrial emissions, automobiles, and rapid forest burning, especially in the tropics. Much of this increase has occurred since 1960. Plants use carbon dioxide from the air for photosynthesis.

"The changes in Amazonian forests really jump out at you," said William Laurance, a U.S. scientist with the Smithsonian Tropical Research Institute in Panama. Laurance was the lead author of the paper, which appeared this week in the scientific journal Nature (Mar 11). "It’s a little scary to realize that seemingly pristine forests can change so quickly and dramatically."


For the past two decades, the research team studied the fate of nearly 14,000 trees in the central Amazon, scattered across a landscape of 120 square miles in area. During the course of the study, most species of trees began growing faster. The forests also became more dynamic, with existing trees dying faster and being replaced by young new trees.

Even more important is that the species composition of the forest is changing. "There clearly are winners and losers," said Alexandre Oliveira of the University of São Paulo, Brazil, another team member. "In general, large, fast-growing trees are winning at the expense of smaller trees that live in the forest understory."

"The decline of many small trees is intriguing because they tend to be so specialized," said Henrique Nascimento, a Brazilian researcher at the Smithsonian Tropical Research Institute. "They live in the dark interior of the forest, and are the only trees that can flower and reproduce in deep shade."

The most likely reason for these changes, say the researchers, is that rising carbon-dioxide levels are fertilizing the forests, leading to faster growth and more competition among trees for light, water, and soil nutrients. Under these conditions, big, fast-growing species of trees probably have an advantage over small, slower-growing trees.

"Sadly, this could be a signal that the forest’s ecology is changing in fundamental ways," said team-leader Laurance. "Tropical rainforests are renowned for having lots of highly specialized species. If you change the tree communities then other species-especially the animals that feed on and pollinate the trees-will undoubtedly change as well."

"This appears to be yet another signal of effects on nature from increasing greenhouse gas concentrations and associated climate change," said Thomas Lovejoy of the Heinz Center for Science, Economics and Environment in Washington, D.C., who helped to establish the tree study in central Amazonian over two decades ago. "We really need more research to see if these remarkable changes are also happening in other tropical forests around the world. If they are, then it’s likely that even the world’s remotest forests are now being altered by human activities."



The Biological Dynamics of Forest Fragment Project, a joint effort of the National Institute for Amazonian Research (INPA) in Brazil and the Smithsonian Tropical Research Institute, seeks to answer questions about plant and animal relations, the biology of extinction, the process of forest regeneration, and the effects of forest edge and fragmentation on the genetic structure of tropical species.

The Smithsonian Tropical Research Institute is an international research center established in Panama by the Smithsonian Institution to increase knowledge of the past, present and future of tropical biodiversity and its importance to humanity. For more than 90 years, researchers, students and associates have conducted research in forest and marine habitats in Panama and at other sites throughout tropical regions of the world.

Dr. William F. Laurance | EurekAlert!
Further information:
http://www.stri.org
http://www.si.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: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

Im Focus: Dozens of binaries from Milky Way's globular clusters could be detectable by LISA

Next-generation gravitational wave detector in space will complement LIGO on Earth

The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...

Im Focus: Entangled atoms shine in unison

A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.

The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...

Im Focus: Computer-Designed Customized Regenerative Heart Valves

Cardiovascular tissue engineering aims to treat heart disease with prostheses that grow and regenerate. Now, researchers from the University of Zurich, the Technical University Eindhoven and the Charité Berlin have successfully implanted regenerative heart valves, designed with the aid of computer simulations, into sheep for the first time.

Producing living tissue or organs based on human cells is one of the main research fields in regenerative medicine. Tissue engineering, which involves growing...

Im Focus: Light-induced superconductivity under high pressure

A team of scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg investigated optically-induced superconductivity in the alkali-doped fulleride K3C60under high external pressures. This study allowed, on one hand, to uniquely assess the nature of the transient state as a superconducting phase. In addition, it unveiled the possibility to induce superconductivity in K3C60 at temperatures far above the -170 degrees Celsius hypothesized previously, and rather all the way to room temperature. The paper by Cantaluppi et al has been published in Nature Physics.

Unlike ordinary metals, superconductors have the unique capability of transporting electrical currents without any loss. Nowadays, their technological...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | 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

 
Latest News

Supersonic waves may help electronics beat the heat

18.05.2018 | Power and Electrical Engineering

Keeping a Close Eye on Ice Loss

18.05.2018 | Information Technology

CrowdWater: An App for Flood Research

18.05.2018 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>