Featured Research

from universities, journals, and other organizations

New model more accurately describes migratory animals' extinction risk

Date:
November 16, 2011
Source:
University of Georgia
Summary:
Predicting the risk of extinction is a complicated task, especially for species that migrate between breeding and wintering sites. Researchers have now developed a mathematical model that may make such predictions more accurate.

A piping plover wanders a beach on Little St. Simons Island in August 2010.
Credit: Image courtesy of University of Georgia

Predicting the risk of extinction is a complicated task, especially for species that migrate between breeding and wintering sites. Researchers at the University of Georgia and Tulane University have developed a mathematical model that may make such predictions more accurate. Their work appears in the early online edition of the Royal Society journal Biology Letters.

Related Articles


"The concern is that for a lot of species, we don't know very much about their wintering grounds," said Richard Hall, assistant research scientist in the UGA Odum School of Ecology. "Here in the U.S. we do a pretty good job of conserving breeding habitat for species of concern, but often we have no idea what kinds of threats are facing their non-breeding areas."

Hall and Tulane University's Caz Taylor developed a new model that builds upon a theory of population dynamics known as metapopulation theory.

"A metapopulation is made up of many sub-populations that live in patchily-distributed sites across a landscape," Hall said.

In its simplest form, metapopulation theory describes the fraction of suitable habitat patches occupied by a species. Individuals from a sub-population emigrate from their original site to colonize previously unoccupied patches of suitable habitat where they either thrive or die out. When the rate of successful colonization exceeds the rate of extinction, the proportion of occupied patches rises and the metapopulation is likely to persist.

The problem with simple metapopulation theory is that it assumes colonization occurs continually and is possible from any adjacent patch. It is therefore not applicable to migratory species that seasonally vacate their breeding sites to move to wintering sites, and vice versa. So while the theory has worked for certain conservation efforts -- such as informing decisions about the extent of suitable habitat needed to support endangered species such as the northern spotted owl in the Northwest and Bachman's sparrow in the Southeast -- it does not fit in all cases.

To adapt the theory for migratory species, Hall and Taylor added more complexity to the model. They divided habitat patches into two categories: those used during breeding season and those used for wintering. In their model, colonization only occurs between breeding and wintering (non-breeding) patches, not between patches of the same type.

"With the migratory model, having an unoccupied breeding patch surrounded by lots of suitable breeding habitat does not necessarily mean that the colonization rate is likely to be high," said Hall. "With migratory animals, the colonists of breeding patches come from non-breeding patches far away."

Piping plovers provide a good example. There are only a limited number of suitable habitat patches -- open, sandy beaches that aren't excessively disturbed by human activity -- so the number and size of the breeding patches in the north and the wintering patches in the south -- and the distances between them -- are well known. Through bird banding and tracking technologies, researchers are beginning to develop an understanding of the migration patterns between breeding and wintering patches. Taylor and Hall's model could be applied to describe these birds' population dynamics.

Hall said that the model highlights the importance of taking into account the colonization and extinction rates at both breeding and non-breeding sites, which is more easily said than done.

"What our model shows is that even if the populations in the breeding areas look healthy, without knowing the state of the non-breeding areas, we could be vastly underestimating the likelihood of extinction," he said.


Story Source:

The above story is based on materials provided by University of Georgia. The original article was written by Beth Gavrilles. Note: Materials may be edited for content and length.


Journal Reference:

  1. C. M. Taylor, R. J. Hall. Metapopulation models for seasonally migratory animals. Biology Letters, 2011; DOI: 10.1098/rsbl.2011.0916

Cite This Page:

University of Georgia. "New model more accurately describes migratory animals' extinction risk." ScienceDaily. ScienceDaily, 16 November 2011. <www.sciencedaily.com/releases/2011/11/111116104518.htm>.
University of Georgia. (2011, November 16). New model more accurately describes migratory animals' extinction risk. ScienceDaily. Retrieved November 29, 2014 from www.sciencedaily.com/releases/2011/11/111116104518.htm
University of Georgia. "New model more accurately describes migratory animals' extinction risk." ScienceDaily. www.sciencedaily.com/releases/2011/11/111116104518.htm (accessed November 29, 2014).

Share This


More From ScienceDaily



More Plants & Animals News

Saturday, November 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Research on Bats Could Help Develop Drugs Against Ebola

Research on Bats Could Help Develop Drugs Against Ebola

AFP (Nov. 28, 2014) In Africa's only biosafety level 4 laboratory, scientists have been carrying out experiments on bats to understand how virus like Ebola are being transmitted, and how some of them resist to it. Duration: 01:18 Video provided by AFP
Powered by NewsLook.com
New Dinosaur Species Found in Museum Collection

New Dinosaur Species Found in Museum Collection

Reuters - Innovations Video Online (Nov. 27, 2014) A British palaeontologist has discovered a new species of dinosaur while studying fossils in a Canadian museum. Pentaceratops aquilonius was related to Triceratops and lived at the end of the Cretaceous Period, around 75 million years ago. Jim Drury has more. Video provided by Reuters
Powered by NewsLook.com
Tryptophan Isn't Making You Sleepy On Thanksgiving

Tryptophan Isn't Making You Sleepy On Thanksgiving

Newsy (Nov. 27, 2014) Tryptophan, a chemical found naturally in turkey meat, gets blamed for sleepiness after Thanksgiving meals. But science points to other culprits. Video provided by Newsy
Powered by NewsLook.com
Classic Hollywood Memorabilia Goes Under the Hammer

Classic Hollywood Memorabilia Goes Under the Hammer

Reuters - Entertainment Video Online (Nov. 26, 2014) The iconic piano from "Casablanca" and the Cowardly Lion suit from "The Wizard of Oz" fetch millions at auction. Sara Hemrajani reports. Video provided by Reuters
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:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

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