Bats in Atlantic Canada are being decimated by a fungus. Do we have what it takes to help populations survive?
When bat researchers are asked why they’ve chosen to study the mammals, the general consensus is, “Bats are cool.” As for the rest of us, bats are not so cool. They are considered by many to be a nuisance at best, or vilified.
Yet consider this: bats are voracious consumers of insects, many of which are agricultural pests. Estimates hold that bats save the US agricultural sector alone anywhere from $3.7 billion to $53 billion a year in pest control costs.
Here’s something else: bats really are cool. They are the only mammal capable of true flight—as opposed to flying squirrels, for example, which glide. And the skin on their wings is like that of a frog: it’s responsible for respiration, water conservation and heat regulation—literally helping bats to keep cool (or warm up, depending on the conditions).
Six years ago, an invasive fungus began killing cave-hibernating bat populations across North America. The fungus, Geomyces destructans, was unwittingly introduced by a tourist into a cave near Albany, New York, and has since spread into 10 states and four Canadian provinces—including Nova Scotia and New Brunswick, as well as Ontario and Quebec.
Now, more than ever, bats are in serious need of some goodwill.
In Atlantic Canada, three commonly seen species of bats—little brown bat, northern long-eared bat, and tri-coloured bat—spend the winter months in caves, where they enter a state of low metabolic and physical activity, subsisting entirely off stored fat reserves until spring. Before or during overwintering, which can last up to eight months, the bats mate.
In summer the sexes segregate, and females seek out dry, hollow spaces in which to give birth and raise pups. The bats in these colonies—known as maternity colonies—are frequently the bats we find living in our attics and barns. (Bats in barns, especially in small numbers, can also be colonies of males.)
During winter, bats conserve energy by lowering their body temperature, and are vulnerable to any disruption that increases the rate at which they normally wake up and warm up. Bats infected with Geomyces destructans waken frequently during hibernation, depleting fat reserves, and are often found with a white nose: hence this disease has been dubbed white-nose syndrome (WNS). Ultimately, these bats starve or freeze to death.
Past, present and future
Dr. Don McAlpine, zoologist and curator of the New Brunswick Museum in Saint John, has studied bats for more than 30 years. He and his graduate student Karen Vanderwolf detected New Brunswick’s first case of WNS in 2011. This year, only a year later, NB’s largest bat population has been decimated: a colony originally numbered in the thousands is reduced to just a handful of individuals, all of them infected with WNS.
To date, 90 per cent of the little brown bat population in NB and NS has been wiped out by WNS, and some researchers believe that the less common northern long-eared bat and tri-coloured bat may be harder hit.
Biologist Dr. Hugh Broders, of Saint Mary’s University, in Halifax, is hopeful that islands like PEI and Newfoundland will be refuges from WNS: one of the questions he is investigating is whether mainland bats—largely infected with WNS—can cross the water to PEI or Newfoundland. If not, the bats of those provinces may be spared the devastating effects of WNS. However, given that the fungus was introduced to North America by tourists and not bats, it could similarly be introduced to PEI and Newfoundland by people.
As for right now, bats in NB and NS are on course for quick extinction.
“We don’t really understand what the impact of this loss is going to be,” says Vanderwolf.
Since defending her graduate thesis, Vanderwolf has secured a two-year contract from the Canadian Wildlife Federation to investigate WNS. She considers herself lucky to get the funding. The devastating nature of WNS leaves a grim future for Atlantic Canadian bats, and when compounded with the lack of funding for research, hope may be especially hard to come by.
Public participation, however, could go a long way in helping bats survive.
How people can help
Don McAlpine says the most important thing the public can do is to protect maternity colonies. This can be done by hanging bat boxes, or by choosing to humanely remove bats living in our homes.
“In New Brunswick, bats have recently been removed from the nuisance wildlife list,” says McAlpine. “An exterminator now has to be much more careful in removing bats from homes, [allowing bats to] receive protection they might [not] have had in the past.”
Dr. Scott McBurney, wildlife pathologist at the Canadian Cooperative Wildlife Health Centre, Atlantic Region, in Charlottetown, agrees. “The public has a really big part in the recovery of these bats. When they are found roosting in our attics, we have to take the appropriate [measures] to remove them in a way that allows them to go on and reproduce.”
Another vital measure is reducing the traffic in caves and abandoned mines in order to minimize disturbance of hibernating bats in late fall, winter, and early spring, and to prevent the accidental spread of the fungus causing WNS during the rest of the year.
“We need to be more aware as humans of what we do because we are now a global society,” says McBurney. People who explore caves—or cavers—are active in this regard, taking measures to encourage tourists and fellow cavers to stay out of caves during fall and winter, and to thoroughly clean spelunking (caving) gear between visits to different caves.
Although there’s still much that’s not understood about bats and white-nose syndrome, what we do know is this: WNS has set the stage for quick extinction of species that make Atlantic Canada home, as well as several other North American species.
Despite the grim prognosis, scientists continue to study bats, hopeful some discovery may unlock a secret to the protection of this unique and mysterious mammal.