By Cassie Piccolo
If you thought there were more black flies and mosquitoes around this summer, you can blame the white-nose syndrome, a deadly fungus (Pseudogymnoascus destructans) that has killed almost all the bats in Nova Scotia. And with a single little brown bat eating up to 1,000 mosquitoes an hour, that’s a lot more mosquitoes in our backyards! This summer’s surprise discovery of a healthy colony in southern Nova Scotia offered at least a small ray of hope that bats might eventually make a comeback.
White-nose syndrome hit Nova Scotia in 2010, when the disease was first introduced into the province. The disease, which originated in Europe, kills bats by disturbing their winter hibernation. The fungus affects their noses, causing them to awaken from hibernation early. With nothing to eat, the bats die of starvation or freezing.
All bat species that hibernate in the Northern latitudes have been affected. The fungus was first detected in North America in New York and has since traveled to many parts of North America. It is predicted that eventually the fungus will spread farther west to affect all of Canada's bat populations.
The winter of 2012-2013 was devastating for Nova Scotia’s bats. Scientists estimate that white-nose syndrome killed 95% of all the bats in the province.
The affected species included the Little Brown Bat, the Northern Long-eared Bat, and the Tricoloured Bat. All three species were added to the province’s list of endangered species in 2013.
The bats of the Eastern Shore have been hit hard. Andrew Hebda, Curator of Zoology at Halifax's Museum of Natural History said that “One large site in your area has been lost due to the disease, and other potential sites are at risk”.
Hebda said that while the bats are in serious danger due to the disease, there is always a chance that bats will recover. Although the mortality rate is estimated at over 95% in the three species, there is the possibility that some populations will be spared—either through luck or by evolving a resistance to the fungus. One lucky colony was found in August of this year in southern Nova Scotia. With over 350 healthy bats, it’s the largest known colony remaining in the province.
Bat re-population is a long process. A female bat has one pup every year or two. At that rate, some colonies may not recover. And any remaining healthy hibernation sites could yet become contaminated.
People exploring caves are some of the remaining bats’ most dangerous enemies. Cavers can pick up the fungus on their clothes in one cave, and then go on to contaminate multiple caves and hibernation sites during their trips underground. Until bat populations have substantially recovered, people should avoid going to all bat hibernation sites. While the disease runs its course, aggressively reducing the risk of human contamination is the best defense for our beleaguered flying mammal friends.
If you’d like to help bats make a comeback, you can sign up for the Nova Scotia Bat Conservation’s bat sighting program. Reports of bat sightings help guide public and private conservation and recovery efforts. To encourage more participation, reports are confidential, and you don’t even have to give the exact location of your sighting. More info on the Nova Scotia Bat Conservation’s website at http://www.batconservation.ca, or you can call 1-866-727-3447.