Navigation Links
Tropical birds return to harvested rainforest areas in Brazil
Date:6/28/2011

Bird species in rainforest fragments in Brazil that were isolated by deforestation disappeared then reappeared over a quarter-century, according to research results published today in the journal PLoS 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 Dinmica Biolgica de Fragmentos Florestais, Instituto Nacional de Pesquisas da Amaznia 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, especially ones that show unexpectedly low extinction rates.


'/>"/>

Contact: Cheryl Dybas
cdybas@nsf.gov
703-292-7734
National Science Foundation
Source:Eurekalert  

Related biology news :

1. GW researchers receive award from NCI to study cancer from a neglected tropical disease
2. Unique gene combinations control tropical maize response to day lengths
3. 2,300-year climate record suggests severe tropical droughts as northern temperatures rise
4. Tropical blueberries are extreme super fruits
5. NASAs Aqua satellite sees weaker Tropical Depression Errol crossing West Timor
6. Surprise! Biodiversity and resource use may co-exist in tropical forests
7. Antifungal compound found on tropical seaweed has promising antimalarial properties
8. The water temperature in the subtropical Atlantic falls due to wind action
9. New tropical mistletoe described just in time for Christmas
10. IP-K extends research deal with Novartis Institute for Tropical Diseases
11. Novel services for tropical forest monitoring with satellite
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Tropical birds return to harvested rainforest areas in Brazil
(Date:12/20/2016)... 2016   Valencell , the leading innovator ... STMicroelectronics (NYSE: STM), a global semiconductor leader serving ... today the launch of a new, highly accurate ... includes ST,s compact SensorTile turnkey multi-sensor ... sensor system. Together, SensorTile and Benchmark deliver the ...
(Date:12/16/2016)... 2016 Research and Markets has announced the ... Forecast to 2021" report to their offering. ... The biometric vehicle access system ... CAGR of 14.06% from 2016 to 2021. The market is estimated ... reach 854.8 Million by 2021. The growth of the biometric vehicle ...
(Date:12/15/2016)... , Dec. 15, 2016   WaferGen Bio-systems, Inc. ... genomics technology company, announced today that on December 13, ... Department of The Nasdaq Stock Market LLC which acknowledged ... price of WaferGen,s common stock had been at $1.00 ... has regained compliance with Listing Rule 5550(a)(2) of the ...
Breaking Biology News(10 mins):
(Date:1/19/2017)... ... January 19, 2017 , ... ... the full spectrum of drug and device development, and Prism Clinical Research ... and clinicians, today announced Verified Clinical Trials (VCT) has been selected ...
(Date:1/19/2017)... Jan. 18, 2017 Acupath Laboratories, Inc., a ... formation of an Executive Committee that will guide the ... John Cucci , a 15-year veteran of ... of Business Development to Chief Sales Officer .  ... served in senior sales leadership roles at several leading ...
(Date:1/18/2017)... According to a new market research report "In situ ... & End User (Molecular Diagnostic Laboratories, Academic and Research Institutions) - Global Forecast ... Million by 2021 from USD 557.1 Million in 2016, growing at a CAGR ... ... MarketsandMarkets Logo ...
(Date:1/18/2017)... , Jan. 18, 2017   Parent Project Muscular ... to end Duchenne muscular dystrophy (Duchenne) , today ... New Jersey Institute of Technology (NJIT) and Talem Technologies ... of robotic technology to assist people living with ... NJIT,s technology – an embedded computer, software, a force ...
Breaking Biology Technology: