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Ontario bats showing signs of recovery after 10 years of die-off
Blair CrawfordMore from Blair Crawford
Updated: December 25, 2019 6:47 PM EST
A decade after a devastating fungus first appeared in Ontario, wiping out up to 95 per cent of the province’s bats, scientists are beginning to see encouraging signs that bats may be on the rebound.
That means that now, more than ever, bats need a helping hand, said Lauren Hooton, a bat biologist and PhD candidate at Trent University in Peterborough.
“I think it’s a lot more hopeful than we originally thought — at least for a couple of species,” Hooton said. “I think the most important thing is to support that. Maintaining bat habitat has always been important, but especially now that they’re having really, really rough winters.”
The epidemic, called white-nose syndrome because of the white fungus that grows on the animals faces and wings, was first identified in New York state in 2006. WNS was found in Ontario and Quebec hibernacula — the formal name for the caves, mines and attics where bats like to roost — in the winter of 2009-2010. It has since spread west into Manitoba and across the U.S. South and Midwest. It’s even jumped the Rockies into California and Washington state.
The fungus causes bats to awaken from hibernation in mid-winter, depleting their fat reserves at a time when there are no insects around to feed on. They die of starvation.
A huge cave near Renfrew that is thought to have been home to upwards of 30,000 bats before WNS arrived, had crashed to just about 2,000 bats by 2015. Other smaller hibernacula lost 100 per cent of its bats within a few years of the arrival of WNS, Hooton said.
“The big picture is that the bats in Ontario — little brown bats, tricoloured, small footed and northern long-eared bats — they’ve experienced a 95 to 100 per cent collapse,” Hooton said.
“The bigger hibernacula like the one in Renfrew County have had a 92 to 95 per cent die off. In the smaller one, the bats are 100 per cent gone.”
Estimating bat populations is difficult. Not only are bats mobile, nocturnal and hard to count, but for the past five years, scientists have been forbidden to enter the hibernacula to prevent further spreading the fungus and to avoid disturbing the already stressed population.
So many bats have died in North America, scientists have given up counting, said Craig Willis, a biologist who runs the Willis Bat Lab at the University of Winnipeg.
“We stopped counting at five to seven million. Now it’s millions and millions and millions,” he said.
Willis collects some data from volunteers in his Bat Watch program, who observe and record bat activity around known colonies. Researchers like Hooton set up non-lethal bat traps outside the entrances of hibernacula to gauge how many bats are entering and leaving. Some bats are tagged with aluminum clips on their forearms so researchers can track movement and recapture rates.
“We have been seeing some really good capture numbers, on par with what we were seeing pre-white-nose,” she said.
Why small numbers of bats have survived the die off has puzzled scientists, but tests show the survivors seems to have a gene mutation that somehow protects them...
Ontario bats showing signs of recovery after 10 years of die-off
Blair CrawfordMore from Blair Crawford
Updated: December 25, 2019 6:47 PM EST
A decade after a devastating fungus first appeared in Ontario, wiping out up to 95 per cent of the province’s bats, scientists are beginning to see encouraging signs that bats may be on the rebound.
That means that now, more than ever, bats need a helping hand, said Lauren Hooton, a bat biologist and PhD candidate at Trent University in Peterborough.
“I think it’s a lot more hopeful than we originally thought — at least for a couple of species,” Hooton said. “I think the most important thing is to support that. Maintaining bat habitat has always been important, but especially now that they’re having really, really rough winters.”
The epidemic, called white-nose syndrome because of the white fungus that grows on the animals faces and wings, was first identified in New York state in 2006. WNS was found in Ontario and Quebec hibernacula — the formal name for the caves, mines and attics where bats like to roost — in the winter of 2009-2010. It has since spread west into Manitoba and across the U.S. South and Midwest. It’s even jumped the Rockies into California and Washington state.
The fungus causes bats to awaken from hibernation in mid-winter, depleting their fat reserves at a time when there are no insects around to feed on. They die of starvation.
A huge cave near Renfrew that is thought to have been home to upwards of 30,000 bats before WNS arrived, had crashed to just about 2,000 bats by 2015. Other smaller hibernacula lost 100 per cent of its bats within a few years of the arrival of WNS, Hooton said.
“The big picture is that the bats in Ontario — little brown bats, tricoloured, small footed and northern long-eared bats — they’ve experienced a 95 to 100 per cent collapse,” Hooton said.
“The bigger hibernacula like the one in Renfrew County have had a 92 to 95 per cent die off. In the smaller one, the bats are 100 per cent gone.”
Estimating bat populations is difficult. Not only are bats mobile, nocturnal and hard to count, but for the past five years, scientists have been forbidden to enter the hibernacula to prevent further spreading the fungus and to avoid disturbing the already stressed population.
So many bats have died in North America, scientists have given up counting, said Craig Willis, a biologist who runs the Willis Bat Lab at the University of Winnipeg.
“We stopped counting at five to seven million. Now it’s millions and millions and millions,” he said.
Willis collects some data from volunteers in his Bat Watch program, who observe and record bat activity around known colonies. Researchers like Hooton set up non-lethal bat traps outside the entrances of hibernacula to gauge how many bats are entering and leaving. Some bats are tagged with aluminum clips on their forearms so researchers can track movement and recapture rates.
“We have been seeing some really good capture numbers, on par with what we were seeing pre-white-nose,” she said.
Why small numbers of bats have survived the die off has puzzled scientists, but tests show the survivors seems to have a gene mutation that somehow protects them...