Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Social Bats Pay a Price: Fungal Disease, White-Nose Syndrome ... Extinction?

04.07.2012
Study determines which bat species are headed for trouble

The effect on bat populations of a deadly fungal disease known as white-nose syndrome may depend on how gregarious the bats are during hibernation, scientists have discovered.

Species that hibernate in dense clusters even as their populations get smaller will continue to transmit the disease at a high rate, dooming them to continued decline, according to results of a new study led by biologists at the University of California, Santa Cruz (UCSC).

One gregarious species has surprised biologists, however, by changing its social behavior.

The joint National Science Foundation (NSF) and National Institutes of Health (NIH) Ecology and Evolution of Infectious Diseases (EEID) Program funded the study. The Directorates for Biological Sciences and Geosciences at NSF supports the EEID Program.

"Managing disease outbreaks appears to be a daunting task, given the complexity of most ecosystems," said Sam Scheiner, EEID program director at NSF. "This study, however, shows that in fact we can identify the key factors needed for adequate management."

White-nose syndrome has decimated bat colonies throughout the northeast since it first appeared in New York in 2006. It continues to spread in the United States and Canada.

In the study, researchers analyzed population trends in six bat species in the northeast.

They found that some bat populations are stabilizing at lower abundances, while others appear to be headed for extinction.

The results, published in the current issue of the journal Ecology Letters, centered around data from bat surveys between 1979 and 2010, covering a long period of population growth followed by dramatic declines caused by white-nose syndrome.

"All six species were affected by white-nose syndrome, but we have evidence that populations of some species are beginning to stabilize," said Kate Langwig of UCSC, first author of the paper.

"This study gives us an indication of which species face the highest likelihood of extinction, so we can focus management efforts and resources on protecting those species."

The bats hibernate during the winter in caves and abandoned mines; the number of bats can vary tremendously from one site to another.

The fungus that causes white-nose syndrome grows on the exposed skin of hibernating bats, disrupting their hibernation and causing unusual behavior, loss of fat reserves and death.

Langwig and co-authors looked at how steeply the bat populations at each site declined after they were hit by white-nose syndrome, and whether the severity of the decline was the same in large and small populations.

They found that for species that hibernate alone, the declines were less severe in smaller colonies. For gregarious species, however, even small colonies declined steeply.

"We found that in the highly social species that prefer to hibernate in large, tightly packed groups, the declines were equally severe in colonies that varied from 50 bats to 200,000 bats," said co-author Marm Kilpatrick of UCSC. "That suggests that colonies of those species will continue to decline even when they reach small population sizes."

Trends in the declines of different bat species since the emergence of white-nose syndrome support these predictions.

As populations get smaller, the declines tend to level off for species that roost singly, but not for socially gregarious species.

Surprisingly, however, one highly social species is bucking the trend.

The little brown bat, one of the most common bat species in the northeast, appears to be changing its social behavior, going from a species that preferred to roost in dense clusters to one in which most bats now roost apart from other bats.

"Our analysis suggests that the little brown bats are probably not going to go extinct because they are changing their social behavior in a way that will result in their persisting at smaller populations," Kilpatrick said.

Another gregarious species, the Indiana bat, continues to hibernate mostly in dense clusters and will probably continue to decline toward extinction.

"Since the appearance of white-nose syndrome, both species have become more solitary, but the change is much more dramatic in the little brown bats," Langwig said.

"We now see up to 75 percent of them roosting singly. For Indiana bats, only 8 to 9 percent are roosting alone, which does not appear to be enough to reduce transmission rates."

Even solitary roosting habits may not be enough to save some species, such as the northern long-eared bat.

Although it declined less rapidly as its colonies got smaller, 14 populations of northern long-eared bats became locally extinct within two years after the detection of white-nose syndrome. No populations remained in the study area after five years.

In contrast, populations of tri-colored bats, another solitary species, stabilized at low levels three to four years after disease detection.

"Northern long-eared bats may be particularly susceptible to the disease, so they continue to get hit pretty hard even after transmission rates are reduced," Langwig said.

The two species least affected by white-nose syndrome--big brown bats and eastern small-footed bats--are mostly solitary, although occasionally they roost in small clusters.

It's not clear why they have been less affected by the disease than other species, Langwig said.

According to Kilpatrick, one possibility is that these species roost in sites where conditions are less conducive to the disease.

The study examined the influence of different microclimates within hibernation sites, and found that declines were less severe in drier and cooler sites.

"It appears that the driest and coolest caves may serve as partial refuges from the disease," Kilpatrick said.

In addition to Langwig and Kilpatrick, co-authors of the paper include Winifred Frick of UCSC; Jason Bried of Oklahoma State University; Alan Hicks of the New York State Department of Environmental Conservation; and Thomas Kunz of Boston University.

Much of the bat population data used in the study was collected in surveys conducted by state agencies during the past 40 years.

This research was also funded by Bat Conservation International and the U.S. Fish and Wildlife Service.

Media Contacts
Cheryl Dybas, NSF (703) 292-7734 cdybas@nsf.gov
Tim Stephens, UCSC (831) 459-2495 stephens@ucsc.edu
Related Websites
NSF Special Report: Ecology and Evolution of Infectious Diseases: http://www.nsf.gov/news/special_reports/ecoinf/index.jsp

NSF News: Investigating the Spread of Infectious Diseases: http://www.nsf.gov/news/news_summ.jsp?cntn_id=121607

The National Science Foundation (NSF) is an independent federal agency that supports fundamental research and education across all fields of science and engineering. In fiscal year (FY) 2012, its budget is $7.0 billion. NSF funds reach all 50 states through grants to nearly 2,000 colleges, universities and other institutions. Each year, NSF receives over 50,000 competitive requests for funding, and makes about 11,000 new funding awards. NSF also awards nearly $420 million in professional and service contracts yearly.

Useful NSF Web Sites:
NSF Home Page: http://www.nsf.gov
NSF News: http://www.nsf.gov/news/
For the News Media: http://www.nsf.gov/news/newsroom.jsp
Science and Engineering Statistics: http://www.nsf.gov/statistics/
Awards Searches: http://www.nsf.gov/awardsearch/

Cheryl Dybas | EurekAlert!
Further information:
http://www.nsf.gov

More articles from Ecology, The Environment and Conservation:

nachricht Dispersal of Fish Eggs by Water Birds – Just a Myth?
19.02.2018 | Universität Basel

nachricht Removing fossil fuel subsidies will not reduce CO2 emissions as much as hoped
08.02.2018 | International Institute for Applied Systems Analysis (IIASA)

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: Developing reliable quantum computers

International research team makes important step on the path to solving certification problems

Quantum computers may one day solve algorithmic problems which even the biggest supercomputers today can’t manage. But how do you test a quantum computer to...

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

Im Focus: Hybrid optics bring color imaging using ultrathin metalenses into focus

For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.

But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...

Im Focus: Stem cell divisions in the adult brain seen for the first time

Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.

The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

The RWI/ISL-Container Throughput Index started off well in 2018

22.02.2018 | Business and Finance

FAU researchers demonstrate that an oxygen sensor in the body reduces inflammation

22.02.2018 | Health and Medicine

Histology in 3D: new staining method enables Nano-CT imaging of tissue samples

22.02.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>