Environmental 'one-two punch' imperils Amazonian forests

June 4, 2014

One of the world's longest-running ecological studies has revealed that Amazonian forests are being altered by multiple environmental threats – creating even greater perils for the world's largest rainforest.

"It's like a boxer getting hit by a flurry of punches," says lead author William Laurance of James Cook University in Cairns, Australia.

For the past 35 years, a team of Brazilian and international researchers has studied how diverse communities of trees and vines respond when the Amazonian rainforest is fragmented by cattle ranching.

The fragmented forests, they found, change rapidly. "Lots of trees have died while vines, which favour disturbed forests, proliferate rapidly," said Jose Luis Camargo of Brazil's National Institute for Amazonian Research.

But the biggest surprise is that nearby undisturbed forests, which were also being carefully studied, changed as well. Trees there grew and died faster, and the vines also multiplied.

"These changes might be driven by increasing carbon dioxide in the atmosphere," said Thomas Lovejoy of George Mason University in Virginia, USA, who initiated the long-term study. "Plants use carbon dioxide for photosynthesis and when it increases, the evidently becomes more unstable and dynamic, as long as the soils have enough nutrients."

The investigators say a key implication is that many forests are being affected not only by land-use changes such as habitat fragmentation, but also by global-scale changes such as rising and climate change. In some cases different drivers reinforce one another, increasing their impacts on forests.

"A big implication is that it's going to be harder to predict future changes to ecosystems if they're being affected by several environmental drivers," said Lovejoy.

The researchers expect such changes to increase in the future.

"Humans continue to dump billions of tons of greenhouse gases into the atmosphere every year, and it's evidently affecting even the remotest forests on Earth," said Laurance.

Explore further: Devastating human impact on the Amazon rainforest revealed

More information: William F. Laurance et al. (2014) Apparent environmental synergism drives the dynamics of Amazonian forest fragments. Ecology. www.esajournals.org/doi/abs/10.1890/14-0330.1

Related Stories

A new look at old forests

June 3, 2014

As forests age, their ability to grow decreases, a new study by Marine Biological Laboratory (MBL) scientists and colleagues has determined. Since most U.S. forests are maturing from regeneration that began about 100 years ...

Future grim for 'biggest and most magnificent' trees

December 7, 2012

Across the world, big old trees face a dire future globally from agriculture, logging, habitat fragmentation, exotic invaders, and the effects of climate change, warn leading scientists in an article published this week in ...

Nutrient-rich forests absorb more carbon

April 14, 2014

The ability of forests to sequester carbon from the atmosphere depends on nutrients available in the forest soils, shows new research from an international team of researchers including the International Institute for Applied ...

Recommended for you

Extreme downpours could increase fivefold across parts of the US

December 5, 2016

At century's end, the number of summertime storms that produce extreme downpours could increase by more than 400 percent across parts of the United States—including sections of the Gulf Coast, Atlantic Coast, and the Southwest—according ...

Climate change will drive stronger, smaller storms in US

December 5, 2016

The effects of climate change will likely cause smaller but stronger storms in the United States, according to a new framework for modeling storm behavior developed at the University of Chicago and Argonne National Laboratory. ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.