The discovery of two Alberta caves being used by hibernating bats has raised the hopes of researchers tracking a disease that has killed millions of bats in Eastern Canada and the United States.
"It is a significant find because it's only the tip of the iceberg," said Cori Lausen, who is leading a new program in which cavers are teaming up with biologists to search for hibernating bats in Alberta and British Columbia.
The researchers used ultrasound recorders to help locate 103 northern myotis and little brown bats in the Alberta foothills.
"This is the first year we've had cavers from across British Columbia and Alberta putting detectors in underground, and we are just starting to get the data," said Dr. Lausen of the Wildlife Conservation Society Canada (WCS). "So the fact we've already got a couple [of finds] means our program is working. … We are actually discovering the places that bats are hibernating, which is our first step in being able to prepare for white nose."
White nose syndrome is a disease that has spread to bat colonies in 25 the United States and five Eastern Canadian provinces since it first emerged in New York State in 2007. The disease is linked to a white, cold-loving fungus (Pseudogymnoascus destructans) that attacks the bats as they sleep in hibernating caves known as hibernacula. Infected bats behave abnormally, disrupting their hibernation to go on daytime flights during the winter, which eats up their fat reserves and leaves them weak and emaciated.
Since the disease emerged, bat populations have declined by 80 per cent in the U.S. and in the Maritimes, Quebec and Ontario. Researchers are afraid it is spreading west. The full consequence of a massive decline in bats is unknown, but the U.S. National Wildlife Health Center has noted that "insect suppression services" provided by bats are worth $4- to $50-billion (U.S.) a year.
To find hibernating bats, the WCS began working with Albertan and B.C. cavers last fall to place electronic recording devices, known as roostloggers, in sites believed to be hibernacula. More than 50 of the instruments, which record bat ultrasound, have been set up in about 30 caves. (In some of the largest caves, more than one device had to be deployed.) They have been recording all winter, and the data is just now being retrieved.
Dr. Lausen says it is hard to determine which caves are used by bats as hibernacula because the creatures don't feed during their winter sleeps and thus don't leave telltale guano stains on the rocks. She says that when roostloggers capture ultrasound, teams of cavers go in to search out the bats.
"Basically, the only way we are going to know if white nose syndrome has arrived in the West is by people [seeing signs of it]," she said.
If the disease continues to spread at its current rate, she says, it may take years to reach British Columbia and Alberta. But there are fears that infected bats could speed up the process by hitchhiking into the area aboard semi-trailers, rail cars or vehicles such as RVs, where they have been known to hide under awnings.
"We are nervous it could hop, skip and jump across the Prairies in that way," she said.
People can also carry the disease on their boots or clothing if they have been in a cave with infected bats. That's why the so-called "bat cavers" working with the WCS take special precautions to ensure they are not contaminated, Dr. Lausen said. But despite such measures, the disease is expected to strike the West sooner or later.
"We have no reason at this point to believe it wouldn't [spread]. Because of that, it's a race against the clock," she said. "At this point, our best hope is to locate as many hibernacula as we can."
She says researchers need to know where the West's hibernacula are in order to monitor the health of colonies and to inoculate the bats if a vaccine is ever discovered.
Martin Davis, a bat caver and biologist who is co-ordinating the program in B.C., says the roostloggers are allowing researchers to focus on hot spots.
"It's a difficult thing [finding hibernating bats] because sometimes these passages are really tall, with massive chambers," he said.
Mr. Davis, who several years ago discovered a hibernacula with 40 bats of five different species near Tahsis on Vancouver Island, says it is easy to overlook the tiny creatures.
"People get this idea of thousands of bats using a cave – and you do see that in the tropics – but [in B.C. and Alberta] it's rare to see bats hibernating in caves and very often you only see one or two," he said.