Featured Research

from universities, journals, and other organizations

Tropical birds return to harvested rainforest areas in Brazil

Date:
June 28, 2011
Source:
National Science Foundation
Summary:
Bird species in rainforest fragments in Brazil that were isolated by deforestation disappeared then reappeared over a quarter-century, according to new research.

The white-plumed Antbird had gone "extinct," then returned, several times in the forest.
Credit: Philip Stouffer/LSU

Bird species in rainforest fragments in Brazil that were isolated by deforestation disappeared then reappeared over a quarter-century, according to research results published June 28 in the journal PLoS (Public Library of Science) ONE. Scientists thought many of the birds had gone extinct.

The research was funded by the National Science Foundation (NSF), and conducted in cooperation with Projeto Dinâmica Biológica de Fragmentos Florestais, Instituto Nacional de Pesquisas da Amazônia and the Smithsonian Tropical Research Institute in Manaus, Brazil.

Lead author Philip Stouffer, an ornithologist at Louisiana State University and co-authors of the paper--Erik Johnson at the National Audubon Society; Richard Bierregaard at the University of North Carolina, Charlotte; and Thomas Lovejoy at The Heinz Center in Washington, D.C.--measured bird populations over 25 years in 11 forest fragments ranging from 2.5 acres to 250 acres in the Amazon rainforest near Manaus, Brazil.

In the first decade of the long-term study, birds abandoned forest fragments and, ornithologists believed, went extinct. Then in the past 20 years, many bird species returned, while others went extinct or remained extinct.

"Through long-term observations of fragmentation in tropical forests, this study provides verification that local extinction is accompanied by continual recolonization, dependent on habitat size," said Saran Twombly, program director in NSF's Division of Environmental Biology, which funded the research.

Although species loss following habitat changes can be inferred, long-term observations are necessary to accurately identify the fate of bird populations, said Stouffer.

As the project began, bird populations were tracked before the forests were cut.

During the first year after cutting, bird species disappeared in what the researchers call "localized extinction," meaning a species has disappeared from a particular area.

The area was fragmented in "cookie cutter chunks" as a result of policies that encouraged use of the land--mostly for cattle--but required landowners to leave a portion of the area uncleared.

Bird populations were measured before the deforestation process began, then again in 1985, 1992, 2000 and 2007.

Now agriculture has diminished, and areas where fragments meet nearby forests are recovering, Stouffer said. "Early on, the small fragments lost most of their understory birds, and the area that was cut had no forest birds at all."

Between the time the forest fragments were created and 2007, when the most recent measurements were taken, all fragments lost bird species, Stouffer said.

Losses ranged from below 10 percent in the largest, least fragmented areas to around 70 percent in the smallest, most fragmented spots.

Both extinction and colonization occurred in every interval. In the last two samples--taken in 2000 and 2007--extinction and colonization were approximately balanced.

The extinction process started with birds leaving or dying out. Now, they're coming back.

Of the 101 species netted--trapped with a fine-mesh "mist net"--before deforestation, the researchers detected 97 in at least one forest fragment in 2007.

"A handful of species have 'gone extinct,' but many more species are in flux," Stouffer said. "They come and go."

The project measured only understory, resident birds and not those that live in the forest canopy or may migrate.

"Our samples are snapshots in time," said Stouffer. "They show that forest fragments have the potential to recover their biodiversity if they're in a landscape that can rebound.

"They're not doomed."

The research demonstrates some of the ways birds exist in a human-modified environment, as well as the effects of allowing a forest to regenerate.

"If we consider a balance of abandoned and returned forests--within a 20-year window--birds will begin to treat the fragments as continuous forest," Stouffer said.

"Although a small subset of species is extremely vulnerable to fragmentation and predictably goes extinct, developing second-growth forest around fragments encourages recolonization."

Species biodiversity in today's forest fragments reflects local turnover, not long-term attrition of species, the scientists found.

They think similar processes could be operating in other fragmented ecosystems, expecially ones that show unexpectedly low extinction rates.


Story Source:

The above story is based on materials provided by National Science Foundation. Note: Materials may be edited for content and length.


Journal Reference:

  1. Philip C. Stouffer, Erik I. Johnson, Richard O. Bierregaard, Thomas E. Lovejoy. Understory Bird Communities in Amazonian Rainforest Fragments: Species Turnover through 25 Years Post-Isolation in Recovering Landscapes. PLoS ONE, 2011; 6 (6): e20543 DOI: 10.1371/journal.pone.0020543

Cite This Page:

National Science Foundation. "Tropical birds return to harvested rainforest areas in Brazil." ScienceDaily. ScienceDaily, 28 June 2011. <www.sciencedaily.com/releases/2011/06/110628112754.htm>.
National Science Foundation. (2011, June 28). Tropical birds return to harvested rainforest areas in Brazil. ScienceDaily. Retrieved September 17, 2014 from www.sciencedaily.com/releases/2011/06/110628112754.htm
National Science Foundation. "Tropical birds return to harvested rainforest areas in Brazil." ScienceDaily. www.sciencedaily.com/releases/2011/06/110628112754.htm (accessed September 17, 2014).

Share This



More Earth & Climate News

Wednesday, September 17, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Scientists Examine Colossal Squid

Raw: Scientists Examine Colossal Squid

AP (Sep. 16, 2014) — Squid experts in New Zealand thawed and examined an unusual catch on Tuesday: a colossal squid. It was captured in Antarctica's remote Ross Sea in December last year and has been frozen for eight months. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Man Floats for 31 Hours in Gulf Waters

Man Floats for 31 Hours in Gulf Waters

AP (Sep. 16, 2014) — A Texas man is lucky to be alive after he and three others floated for more than a day in the Gulf of Mexico when their boat sank during a fishing trip. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Researchers Explore Shipwrecks Off Calif. Coast

Researchers Explore Shipwrecks Off Calif. Coast

AP (Sep. 16, 2014) — Federal researchers are exploring more than a dozen underwater sites where they believe ships sank in the treacherous waters west of San Francisco in the decades following the Gold Rush. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Isolated N. Korea Asks For International Help With Volcano

Isolated N. Korea Asks For International Help With Volcano

Newsy (Sep. 16, 2014) — Mount Paektu volcano in North Korea is showing signs of life and there's not much known about it. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

    Environment News

      Technology News



      Save/Print:
      Share:  

      Free Subscriptions


      Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

      Get Social & Mobile


      Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

      Have Feedback?


      Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
      Mobile iPhone Android Web
      Follow Facebook Twitter Google+
      Subscribe RSS Feeds Email Newsletters
      Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins