On October 1, 2013 the United States Fish and Wildlife Service (USFWS) proposed listing the northern long-eared Bat (Myotis septentrionalis) as a federally endangered species. Currently it is in a 60 day review period, but most likely this species will be officially listed after this period of time. I have spent several years studying bats and have focused a great deal of my research on this species. It is tough to see a species that you have come to know very well, once common, in rapid decline. This species, that can be abundant in forested habitat throughout its range, is being hit hard by the emerging fungal pathogen White Nose Syndrome. White Nose Syndrome was first documented in New York in 2006 and has spread rapidly. It was first documented in southern Ohio in 2011 and in Cleveland Metroparks in 2012. This disease infects bats during their hibernation. It is a cold loving fungus that thrives in 40-50 degree, humid environments and grows within the skin membrane destroying tissue, disrupting circulation and causing the bat to awaken, groom and consume valuable energy in the process. The result is the bat either dies in the cave or leaves to try and find food and freezes to death. In addition to northern long-eared bats, little brown and tri-colored bats seem to be hit hard from this disease. Mortality rates can be over 90% in an infected cave.
Here are a few questions that I am often asked about White Nose Syndrome and my thoughts on each.
- Where did White Nose Syndrome come from?
There is strong evidence that this fungus was introduced from Europe. Using gene sequencing, scientists have matched the US strain to a strain in European bats. It is thought that someone most likely visited a cave in Europe and then visited the US and entered a cave in New York. Once the fungus became established, it most likely spread to other locations by both humans and bats.
- Are bats showing resistance or recovering?
It is a bit early to tell, but at this point in areas that were first infected the numbers are so low that recovery will take a very long time. Most bats only give birth to one or maybe two pups a year and those have a very high mortality within their first year
. Those that may survive to build a resistance will take a very long time rebuild a population. The good thing they have going for them is that they typically are long lived mammals once they make it through the first winter. A slight increase in numbers, while encouraging, can be just error in locating and counting all the bats.
- What can I do to help?
This is a real tough question. We all want to help, but there is not much we can do at this time except to try and slow the spread. Donating money to organizations that provide funding is crucial. Ongoing research in the pathogen and solutions needs to continue. Each of us needs to help in slowing the spread of White Nose Syndrome by adhering to the set rules limiting access to cave and other locations that have been infected. There has been some progress and one promising project is the creation of artificial caves that can be decontaminated each year.
To date it is believed that over 6.5 million bats have died from White Nose Syndrome and that number will continue to grow as the disease continues to spread. The impacts to ecosystems are still not known, but staying optimistic is important. Big brown bats, one of the most common and widespread bats, have not been hit as hard as other species. They can tolerate a wide range of hibernating temperatures and humidity, allowing them to hibernate in areas that are not ideal for the fungus to persist. Virginia big-eared bats, which are listed as a federal endangered species, seem to be doing fine in infected caves. They normally wake every couple of days, jump starting their immune system, allowing them to stay free of infection. There are other bats that don’t hibernate like red and hoary bats, sidestepping at least this threat. In other parts of the country, like the dessert southwest, conditions in caves are not suitable for White Nose Syndrome. There will be bats, just the number
s and diversity are sure to change.
In the end, the best thing we can all do is to continue to be good stewards of the land. Protecting habitat, supporting conservation, and doing all the little things in our homes and communities to provided the best opportunities for our bats to survive.