Bat attack: a deadly plague threatens North America's bats. Can it be stopped?
Every winter, thousands of tiny bats blanket the walls of the abandoned Hibernia mine in New Jersey. The mine is the biggest bat hibernaculum in the state. The animals come here to hibernate, or be in a dormant sleeplike state, through the cold months. Hibernation allows bats to live off their reserves of body fat while food supplies are low. "Winter surveys [of the mine] had been relatively consistent at about 27,000 to 30,000 bats over the past couple of decades," says MacKenzie Hall, a biologist with the Conserve Wildlife Foundation in New Jersey. Sometimes bats form tight clusters of up to 400 per square foot.
Last winter, however, researchers witnessed a different scene. They counted only about 700 bats in the Hibernia mine. Their numbers had plummeted because of a mysterious illness called white-nose syndrome that has decimated more than 90 percent of the area's bat population.
White-nose syndrome, so named because of the telltale fuzzy white bloom found on infected bats' noses, was first discovered in bats in a New York cave in 2006. Since then, it has rapidly spread across 16 states in the northeastern and central United States and three provinces in Canada, wiping out as many as 1.5 million bats of at least eight cave-hibernating species (see The Spread of White-Nose Syndrome, right). Scientists expect the illness to continue to spread west, threatening the extinction of North America's most common bat species, the little brown bat (Myotis lucifugus), within the next 15 years.
The white, powdery substance that appears on the muzzles, ears, and wings of affected bats is a cold-loving fungus known as Geomyces destructans. More than 95 percent of afflicted bats die, many during the hibernation period and others a short time after leaving their winter roosts. Why? Hundreds of people across the country, from scientists and cavers to wildlife rehabilitators and government officials, are hard at work trying to find out.
Researchers have some theories: They suspect that the fungus growing on the bats irritates the animals, rousing them from hibernation. Though bats normally wake every few weeks during the winter, each time they do, they use up a portion of their stored body fat. If the bats wake too often, they deplete their energy reserves and starve to death. Bats that have contracted G. destructans have also been found to lose more body fluids, causing them to suffer from dehydration. If they survive until spring, bats may still die after leaving their hibernacula because white-nose syndrome causes severe wing damage, limiting their ability to fly and forage for food.
The fungus has even been found in several countries in Western Europe, though the European bats do not develop white-nose syndrome. Perhaps bats there had a mass die-off at some point in history and are now immune to the effects of the fungus. Many experts suspect that cavers in Europe brought the fungus to the U.S.
WHY SAVE BATS?
With more than 1,100 species, bats represent nearly a quarter of the world's mammals. North America has 45 native bat species. Each is essential to its local ecosystem. Most bats are insect-eaters and help control the population of harmful pests. Some bats are fruit-eaters and help to disperse seeds; others pollinate fruit-bearing plants like banana and mango.
Without bats, the populations of destructive and often dangerous insects would rise, likely resulting in increased use of toxic and costly pesticides. A single mouse-size little brown bat can devour as many as 1,000 mosquitoes in an hour.
HELP ON THE WAY
Jackie Kashmer, a wildlife rehabilitator and director of New Jersey Bat Sanctuary, nurses bats with white-nose syndrome back to health. "It's important to know that bats can survive this thing," she says. With proper care, 100 percent of afflicted bats can survive.
Discovering white-nose syndrome in its early stages may help save bats' lives. Fungi often fluoresce under ultraviolet (UV) light, so bats with the disease have spots that glow. "UV [light] can be used to identify early stages of G. destructans long before the typical white fungus is visible," says John Gumbs of BATS Research Center in Pennsylvania. Identifying these bats allows scientists to separate them for further study while minimizing contact with, and disturbance of, nearby bats.
Researchers are also testing various fungicides to see if they can be used to decontaminate bats. Others have built heaters that prevent bats from having to expend too much energy if white-nose rouses them during hibernation. The Nature Conservancy has an even more ambitious plan: to build an artificial bat cave in Tennessee, where scientists can test potential remedies for white-nose syndrome in a controlled setting (see Safe Haven for Bats, below).
Another pressing question is whether bats that have recovered from white-nose syndrome become immune to it. To find out the answer, bats from Kashmer's rehabilitation center will be brought back to hibernacula in New Jersey and Pennsylvania. Scientists will monitor them to see if they remain free of white-nose syndrome. If so, then the future for North America's bats might be better than scientists currently fear.
[WHAT DO YOU THINK?]
Some people suspect that cavers might help spread G. destructans. For this reason, many government-owned caves are now closed to caving. Some people want all caves to be off limits. What's your opinion?
THE SPREAD OF WHITE-NOSE SYNDROME
Since white-nose syndrome was first discovered in bats in New York in 2006, it has spread rapidly across much of North America. Have any bats in your state been found to have white-nose syndrome?
SAFE HAVEN FOR BATS
Scientists at the Nature Conservancy are proposing to build an artificial cave next to an existing bat cave in Tennessee. The cave could be disinfected of G. destructans, thus creating a safe haven for bats. If bats failed to go to the cave on their own, then scientists could use the artificial cave as an on-site laboratory, bringing bats in and studying antifungal agents and their effects on G. destructans.
NATIONAL SCIENCE EDUCATION STANDARDS:
Grades 5-8: Populations, resources, and environments
Grades 9-12: Interdependence of organisms
COMMON CORE STATE STANDARD:
1. Write arguments to support claims with clear reasons and relevant evidence
Understand how a mysterious fungus threatens North American bats and what is being done to save them.
* Why are bats important to the ecosystem? (They consume large amounts of insect pests, pollinate plants, and disperse seeds.)
* How many bat species are there in the world? (more than 1,200)
1. Go online to www.scholastic.com/scienceworld. Open up the digital edition to pages 8-9 and have students do the santo in their magazines. Call on a volunteer to read the headline and the text just below it. As a class, predict what the story will be about.
[TEXT HIGHLIGHTER] 2. Have another student use the highlighting tool to highlight the word hibernaculum in the opening paragraph. Ask the class what the word means.
[DIGITAL STICKY NOTES] 3. Write the definition on a sticky note. (a place where bats hibernate during the cold months) Ask a student to read the first two paragraphs to set the scene.
4. Pass out the "What's the Problem?" work sheet from the online skills sheet database at www. scholastic.com/scienceworld. Have students work in cooperative groups to read the article and identify the problem facing bats and list possible solutions on the work sheet.
[DIGITAL STICKY NOTES] 5. Have a representative from each group type one possible solution onto a digital sticky note. Then lead a discussion about the viability of their possible solutions. Which seems like it would be the most beneficial to the preservation of North American bat populations? Do your students think that bats will overcome and develop immunity to this disease? Why or why not?
Read the text in the box labeled "What Do You Think?" on page 11: "Some people suspect that cavers might help spread G. destructans. For this reason, many government-owned caves are now closed to caving. Some people want all caves to be off limits. What's your opinion?" Conduct a classroom debate about whether cavers could contribute to the spread of this fungus.
Go over the class's responses to the "What's the Problem?" work sheet. Did they understand what scientists are doing to help? Do they offer evidence to support their opinions?
DON'T TEACH BIOLOGY?
Go to www.scholastic.com/scienceworld to download these assessment skills sheets instead:
EARTH SCIENCE: FAMOUS CAVES
Many famous caves can be found around the world. Some contain cultural remnants, such as ancient drawings; others contain natural phenomena that can't be found anywhere else. Try out this mapping activity to learn about a few of these famous caves and where they are located.
PHYSICS: LISTENING TO BATS
Biologist Bruce Miller uses a listening device to study bat populations in Belize. Read this passage to learn more about his work with the Anabat detector which analyzes bat calls.
* VIDEO EXTRA: Watch a video about white-nose syndrome at: www.scholastic.com/scienceworld.
* Find more information about white-nose syndrome from the U.S. Fish and Wildlife Service Web site at: www.fws.gov/northeast/pdf/white-nosefaqs.pdf.
* 2011-2012 is the "Year of the Bat." Learn more about this bat-conservation program sponsored by the United Nations and how you can help at: www, yearofthebat.org.
|Printer friendly Cite/link Email Feedback|
|Title Annotation:||BIOLOGY: PRESERVATION; white-nose syndrome|
|Date:||Oct 17, 2011|
|Previous Article:||Halloween numbers.|
|Next Article:||Marijuana facts: breaking down the myths.|