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 Loss of habitat causes double damage to species richness
02.04.2019 | Deutsches Zentrum für integrative Biodiversitätsforschung (iDiv) Halle-Jena-Leipzig

nachricht Deep decarbonization of industry is possible with innovations
25.03.2019 | Fraunhofer-Institut für System- und Innovationsforschung (ISI)

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: Energy-saving new LED phosphor

The human eye is particularly sensitive to green, but less sensitive to blue and red. Chemists led by Hubert Huppertz at the University of Innsbruck have now developed a new red phosphor whose light is well perceived by the eye. This increases the light yield of white LEDs by around one sixth, which can significantly improve the energy efficiency of lighting systems.

Light emitting diodes or LEDs are only able to produce light of a certain colour. However, white light can be created using different colour mixing processes.

Im Focus: Quantum gas turns supersolid

Researchers led by Francesca Ferlaino from the University of Innsbruck and the Austrian Academy of Sciences report in Physical Review X on the observation of supersolid behavior in dipolar quantum gases of erbium and dysprosium. In the dysprosium gas these properties are unprecedentedly long-lived. This sets the stage for future investigations into the nature of this exotic phase of matter.

Supersolidity is a paradoxical state where the matter is both crystallized and superfluid. Predicted 50 years ago, such a counter-intuitive phase, featuring...

Im Focus: Explosion on Jupiter-sized star 10 times more powerful than ever seen on our sun

A stellar flare 10 times more powerful than anything seen on our sun has burst from an ultracool star almost the same size as Jupiter

  • Coolest and smallest star to produce a superflare found
  • Star is a tenth of the radius of our Sun
  • Researchers led by University of Warwick could only see...

Im Focus: Quantum simulation more stable than expected

A localization phenomenon boosts the accuracy of solving quantum many-body problems with quantum computers which are otherwise challenging for conventional computers. This brings such digital quantum simulation within reach on quantum devices available today.

Quantum computers promise to solve certain computational problems exponentially faster than any classical machine. “A particularly promising application is the...

Im Focus: Largest, fastest array of microscopic 'traffic cops' for optical communications

The technology could revolutionize how information travels through data centers and artificial intelligence networks

Engineers at the University of California, Berkeley have built a new photonic switch that can control the direction of light passing through optical fibers...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Revered mathematicians and computer scientists converge with 200 young researchers in Heidelberg!

17.04.2019 | Event News

First dust conference in the Central Asian part of the earth’s dust belt

15.04.2019 | Event News

Fraunhofer FHR at the IEEE Radar Conference 2019 in Boston, USA

09.04.2019 | Event News

 
Latest News

Proteins stand up to nerve cell regression

24.04.2019 | Life Sciences

New sensor detects rare metals used in smartphones

24.04.2019 | Life Sciences

Controlling instabilities gives closer look at chemistry from hypersonic vehicles

24.04.2019 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>