ArraySeptember 11, 2018 at 9:52 pm
[caption id="attachment_3119" align="alignright" width="449"] The installation crew and the first ever bat gate installed in Maine.[/caption]
By Shevenell Webb, MDIFW Wildlife Biologist
The Department and the U.S. Fish and Wildlife Service recently installed the first ever bat gate in the state which is designed to prevent people from unintentionally disturbing bats and spreading white-nose syndrome.
White-nose syndrome is caused by a fungus and is often fatal to hibernating bats. It has wiped out entire bat colonies and killed more than 6 million bats across North America. The fungus is an irritant which causes bats to wake up and fly around during winter when they should be hibernating, and conserving their energy until spring. It continues to spread in all directions and decimate bat populations.
Eight species of bats live in Maine, but we’ve only found a handful of traditional hibernacula (places where bats hibernate), such as caves and mines. Protecting these locations is critical to saving bats from further declines, and that’s why here in Maine, it is illegal to enter hibernacula from October 1 to April 30. Limiting contact between people and bats is one way for us to limit the spread of white-nose syndrome by humans, and we can help bats survive by eliminating disturbance by humans while they hibernate.
[caption id="attachment_3114" align="alignleft" width="446"] This former mine is an ideal hibernacula for bats. Installation of the gate will allow bats to enter and exit, but will help limit the spread of white nose syndrome.[/caption]
Scientists have discovered that white-nose syndrome is primarily passed from bat to bat or from hibernacula surfaces to bats, but can be spread by people because spores of the fungus may cling to clothing, backpacks, and shoes. When people visit caves and mines during any time of year, they could transport the fungus to uninfected areas and unknowingly cause the deaths of many bats (sometimes in the hundreds) in the process.
Unfortunately, it will take many years for bat populations to recover from the effects of white-nose syndrome. Unlike other small mammals that are prolific breeders, most female bats only have one pup each year. Bats that were once common in Maine, like the little brown bat and northern long eared bat, are now listed as state endangered species and the northern long eared is listed as threatened under the federal endangered species act. We’ve seen declines of more than 90 percent for some of these populations.
Under normal conditions, bats go into hibernation with enough fat reserves to survive the winter. During hibernation, bats wake up periodically. Waking up from hibernation is an energetically expensive process, causing bats to use up some of their fat and muscle reserves. One study of hibernating little brown bats found that every time a bat wakes up, it uses enough fat reserves to last for over 60 days of hibernation. Imagine if people visited a hibernacula three times over the winter- that could result in 180 days less of fat reserves that would help the bat survive the winter! Although most people don’t realize it, they have a significant and potentially deadly effect on bats when they enter hibernacula in the winter.
Gating bat hibernacula is not as simple as it sounds. The 10 ft. by 8 ft. steel gate took us 12 hours to construct and weighed just under 1 ton. We had to carry all the individual pieces of steel and construction equipment by hand to the site. Although the job was not easy, it was satisfying to know that this type of bat gate has successfully conserved bats all over North America. The unique design does not alter local environmental conditions that bats are sensitive to (e.g., temperature, air flow), and allows bats to come and go freely.
We hope the public will respect bat gate structures and understand that limiting visitation to hibernacula benefits bats and people. Bats benefit us many ways, including providing pest control for crops and forests and eating pesky bugs in our backyards and gardens. Protecting bat hibernation sites is just one way we can help these species survive and recover from the effects of white-nose syndrome.
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