Blog dedicated primarily to randomly selected news items; comments reflecting personal perceptions

Monday, July 13, 2015

Sounding The Alarm

"Thousands and tens of thousands of bats dead. I mean, garbage bags full of little carcases [from one Nova Scotia colony alone]."
"The situation is extremely dire for northern long-eared bats, and very dire for little brown bats."
"If there is no evidence of reproduction happening, if there's no evidence of a survival response, then we need to do more dramatic things if we want to keep these bats from going extinct."
"It's important to see if we can do these things [treating bats]. But it's also important to think about whether they are a good idea. If they're effective, they could reduce the pressure on bats. (But) do we want to be doing this stuff forever? And is there a risk of the pathogen developing a resistance?"
"It could really help us [a corps of volunteer bat watchers] get some data on locations and particularly the numbers of bats so we can understand how many bats there are in the summer. We can visit some of the most promising colonies so we can get a handle on who's reproducing and the impact of the disease."
Craig Willis, biologist, University of Winnipeg
Little brown bats
A group of little brown bats hibernate at one of PhD candidate Mary-Anne Collis' study sites. She's one of several graduate students studying bats at the University of Winnipeg Willis Bat Lab. (Mary-Anne Collis)
"I'm not sure I can cope with it being without bats [ returning to a vast bat colony near Renfrew]. When I first went there, it was the 10th of May in 1965, and even then, in May, there were lots of bats. In the middle of winter there would be 20,000 bats there. Lately if you went, you'd be lucky to see 500."
"There's lots of big browns. There's no shortage of them at all. Unfortunately, with White-nose [Syndrome, a bat-deadly fungus], it's more what we don't know than what we do know."
Brock Fenton, professor emeritus, Western University
Little Brown Bat
The little brown bat usually roosts in tree hollows, under eaves or inside crevices of cabins. The species has now been listed in Manitoba as "threatened," the second-highest level of risk designation after "endangered." (Mary-Anne Collis)

First identified in a New York State cave in 2006, the then-emergent threat to the North American bat population has intensified as White-nose Syndrome has continued to spread inexorably through Eastern Canada from Nova Scotia to Thunder Bay and southward, and westward across the United States. As it spreads from one bat colony to another, it wreaks wholesale devastation. The deadly fungus is held to have been brought by inadvertence into North America from Europe.

An estimated seven million North American bats have died since White-nose Syndrome first began its deadly eradication of bats. The deadly white fungus appears to grow on the noses and wings of hibernating bats. Scientists believe that the fungus interferes with the bats' ability to hibernate. Its presence tends to rouse bats from sleep far more frequently than the natural every two or three weeks for an hour or so, causing them to wake three times more frequently. The situation is responsible for depleting their fat stores, leaving them dehydrated and starving.

A bat with white-nose syndrome is shown in Greeley Mine, Vermont, in 2009.

Bats tend to enter their caves communally in great numbers, huddling together in hibernacula and their close proximity to one another ensures that transmission from one infected bat to another is more efficient in spreading White-nose Syndrome. In contrast to the tendency of most bat species to live in close contact with one another through their hibernation periods, there are loner bats like the big brown bat that shelters in buildings and it has been less affected by White-nose Syndrome.

And there is also the syndrome of "survival of the fittest" at play here, where some bats appear to be able to survive the infection. That in itself presents as a hopeful sign, that these bats may reproduce and their genetic ability to withstand the deadly effects of White-nose Syndrome may result in nature cultivating a new type of bat resistant to WNS's fatal effect. On the other hand scientists have discovered some treatments that seem to control the fungus. The long-term effects of the treatments are unknown however, with respect to their potentially harmful effect on the environment.

Craig Willis (left) and Jamie Turner check their climbing gear before entering a cave in central Manitoba.

And the fear as well exists, that treatment of the bats might have an ultimately deleterious effect in halting nature's plan to have her creatures develop their own mode of resistance to the fungus. And as always when science steps in to produce an effective treatment for an infection or a disease the possibility arises that the challenged pathogen will develop a resistance of its own, or transform itself to the point where the treatment becomes ineffective, in which case the problem returns to its original puzzling challenge to surmount.

There has been an established "Neighbourhood Batwatch Program", where has enlisted the aid of people willing to help scientists keep track of activities emanating from known bat colonies. In operation in Quebec, the Batwatch is expanding into Ontario. It is funded partially by the Species at Risk Stewardship Fund. Volunteers committing their assistance can sign out a "bat detector", an electronic device which transforms bats' echolocation calls into sound that humans can hear to enable them to track the bats in their neighbourhood.

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