White-nose syndrome has killed up to 6.7 million bats

A biologist holds a Townsends big-eared bat. PHOTO USFWS.

Outbreak may be the worst wildlife epidemic in North America’s recorded history

By Summit Voice

SUMMIT COUNTY — Federal biologists this week upped their estimates of bat deaths from white-nose syndrome, after recent surveys showed that the disease has killed all bats at some locations, although a few isolated populations have survived in a few spots.

At least 5.7 million to 6.7 million bats have succumbed to the disease, first discovered in New York in 2006. Since then, it has spread northward to Novia Scotia and southwest to Tennessee, infecting bat colonies in 16 states and four provinces.

The outbreak is the worst wildlife disease epidemic in North America’s history. Congress recently directed the Department of the Interior to allot $4 million for research and management of the disease.

“This number confirms what people working on white-nose syndrome have known for a long time — that bats are dying in frighteningly huge numbers and several species are hurtling toward the black hole of extinction,” said Mollie Matteson, with the Center for Biological Diversity, which has filed several petitions to save bats and stem the spread of the disease. “We have to move fast if we’re going to avoid a complete catastrophe for America’s bats.”

“This startling new information illustrates the severity of the threat that white-nose syndrome poses for bats, as well as the scope of the problem facing our nation. Bats provide tremendous value to the U.S. economy as natural pest control for American farms and forests every year, while playing an essential role in helping to control insects that can spread disease to people,” said Fish and Wildlife Service Director Dan Ashe. “We are working closely with our partners to understand the spread of this deadly disease and minimize its impacts to affected bat species.”

The new mortality estimate was calculated by biologists who met last week at the Northeast Bat Working Group’s annual meeting in Pennsylvania, one of the states hit hardest by the bat die-off. The grim figure follows recent news that a few surviving bats were confirmed in Vermont this past summer — a discovery that had buoyed hopes that some individuals may have resistance to the devastating disease, meaning they could possibly form the nucleus of a future recovery effort.

Overall populations of affected bat species in places like Vermont, New York, Pennsylvania and other parts of the Northeast are down 70 percent to 98 percent  since 2006, which also makes the populations more vulnerable to other threats, such as habitat loss, human persecution and environmental contaminants.

“America’s bats are in the throes of an unprecedented crisis and some species face the very real prospect of extinction,” Matteson said. “While it’s heartening to see some money allocated for white-nose syndrome, today’s new mortality estimates are a wake-up call that we need to do more, and fast.”

White-nose syndrome has affected six bat species so far; it kills them during their hibernation period, when they occupy caves and mines in a state of “suspended animation.” The affected bats are insect eaters; their hibernation is a response to a lack of prey available during the winter months.

The loss of so many bug-eating bats has likely had an impact on insect populations, including those that are pests on crops. Scientists have estimated that bats save farmers between $3.7 billion and $53 billion per year on pesticides that did not have to be used on crops like corn, cotton, vegetables and fruit because of the help bats give. Since the bat disease has only shown up in the Midwest and South in the last couple of years, the full effects of declining bat numbers on regions more strongly dominated by agriculture than the Northeast may take some time to show up.

The South and Midwest contain some of the largest and most diverse bat colonies in the world. Already one federally endangered bat has been hit by the disease; the Indiana bat has declined by 70 percent in the Northeast since 2006, though it had been on an upward trajectory in that region before the onset of the disease.

Scientists fear that as white-nose syndrome spreads in the Midwest, the species’ core range, the total population of Indiana bats could plummet. Other bat species are at risk too, and three are currently under review by the U.S. Fish and Wildlife Service for addition to the endangered species list due to the threat posed by white-nose syndrome.

Bats with white-nose syndrome exhibit unusual behavior during cold winter months, including flying outside during the day and clustering near the entrances of caves and mines where they hibernate. Bats have been found sick and dying in unprecedented numbers near these hibernacula.

Estimating the total number of bat deaths has been a difficult challenge for biologists. Although consistent population counts for federally listed endangered bats, like the Indiana bat, have been a priority for state and federal biologists, establishing population counts of once “common” bat species, like little brown bats, was historically not the primary focus of seasonal bat population counts.

“White-nose syndrome has spread quickly through bat populations in eastern North America, and has caused significant mortality in many colonies,” saidDr. Jeremy Coleman, coordinator of a national, interagency effort formed to study the disease. “Many bats were lost before we were able to establish pre-white-nose syndrome population estimates.”

The USFWS is the primary resource for up-to-date information and recommendations for all partners, such as important decontamination protocols for cave researchers and visitors and a cave access advisory that requests a voluntary moratorium on activities in caves in affected states to minimize the potential spread of WNS.

In addition to developing science-based protocols and guidance for land management agencies and other partners to minimize the spread of WNS, the Service has funded numerous research projects to support and assess management recommendations and improve our basic understanding of the dynamics of the disease.


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