White Nose Syndrome is a fungal disease that has been contributing to the deaths of vast numbers of bats in northern New England. But scientists have found that a bacteria in the soil has been linked to some bats’ ability to survive this disease. For more on this, we turn to David Brooks. He’s the author of the weekly Granite Geek science column for the Nashua Telegraph and he blogs at Granitegeek.org. He spoke with NHPR's Peter Biello.
How does white nose syndrome kill a bat?
It kills the bat by waking them up, of all things. It's sort of like, as humans age, we wake up in the middle of the night, well the bats wake up in the middle of hibernation. Because they’re a flying mammal, they use up a lot of energy, and they need to eat a lot of food to survive, so over the winter, when there isn’t much food out there, there aren’t many insects, they basically shut down. In fact, when I talked to the state’s bat specialist, Emily Preston, she said they really almost die, they go to the verge death.
When they’re hibernating?
When they’re hibernating, exactly. They do this all winter. And when the fungus grows into them, it actually wakes them up, and they go out and start feeding, and there’s nothing to eat, so basically they starve to death. It’s absolutely devastating. It’s killed 99% plus of the population of some bats in New Hampshire, throughout the Northeast, really throughout the whole eastern US, and it’s spread to the Midwest.
What about this bacteria is giving researchers hope?
It’s found in nature, so it would be easily spread. That’s part of the good thing about it. And it appears to dampen down the fungus on the bats. It’s only been studied in a lab, as Emily Preston was careful to point out. It’s only been studied on a relatively small number of bats. It’s not clear whether it works widespread on all colonies, or, if so, how it could be applied in the wild, but it’s the first time they found anything that seems to slow down or even reverse the growth of fungus on the bats.
How is the bat population? Is it on the rebound in New Hampshire?
No. It’s not shrinking as fast anymore, probably, which is about the best you can say, which is actually not too bad, because a couple of years ago, it seemed like we’d lose pretty much all our bats and apparently that’s not going to happen, but it still is a little uncertain. There are populations of bats, particularly in New York state, where it was first found, and in Vermont, where it hit early, there are populations of bats that are still living in areas that are completely covered with White Nose. And one of the other signs going above and beyond having the bacteria that can fight the disease is that maybe it’s possible for some bats to survive and pass on some kind of gene or trait that would allow other bats to survive, so natural regeneration. One possibility is that these are just greedy bats, so they eat lots more during the fall than the other bats do and therefore when they wake up during hibernation, it doesn’t quite kill them. If that’s the case, then it doesn’t sound like a terribly hopeful sign, because for one thing it’s probably not genetic so it wouldn’t be passed onto other generations. But who knows? So that’s another very small sign of hope.
How will scientists try to determine the health of the bat population going forward?
That’s a tricky one. New Hampshire doesn’t really have caves because we have the wrong geology. We have 11 official “hibernaculum” which is a place that bats gather to hibernate over the winter. Usually those are in caves but in New Hampshire it’s going to be in rock piles like that. Those hibernaculum is where the population went from 4,000 down to forty. But there’s other bats flying around, the little brown bat, and the big brown bat—not very clever species names, I have to say. They don’t live in hibernaculum; they live in barns and houses. I used to have some in my barn, and I haven’t seen them in a number of years. I have friends and in their barn there are bats, but I’m not sure which species it is that seems to have returned. So it’s not clear how many of those are out there. There is a program that NH Fish and Game is running asking people if they have some of these populations in their old buildings, you can actually fill out a form and try to keep an eye on it and count them and help them keep track of it. You can go to the NH Fish and Game website, hunt that up. It’s called the “Bat Tracker.”
And you also write that scientists are starting to use echolocation to try to track these bats.
We’re doing some of that to try to get population estimates, but it’s really, really rough, which is why it’s so hard to say if the population is declining, has bottomed out, or maybe been on the rebound.