Fort Knox Has a Treasure Other Than Gold

Since there are nearly 200 members of KY EXCEL, the Commonwealth’s voluntary environmental leadership program that is located in the Department for Environmental Protection, the program has more than 200 ongoing projects at any given time. Projects are chosen by the individual members and are as diverse as the members themselves. From recycling at home and work to planting rain gardens to minimizing air emissions to conserving water and energy, each member has the opportunity to make a difference in protecting our environment. Sometimes that difference is unusual and directly affects wildlife, which is true of one of the KY EXCEL projects undertaken by program member Fort Knox.

Fort Knox, a U.S. military installation located near Louisville, may be known for storing the nation’s gold bullion, but there is something else about it that is special. The facility has one of the largest known maternity colonies of federally endangered Indiana bats within the range of the species and the largest in Kentucky. The first maternity colony of Indiana bats on Fort Knox (approximately 150 individuals) was discovered in 1999. The total number of Indiana bats in existence has declined due to white-nose syndrome, a devastating wildlife disease; a lessening and contamination of their insect food supply due to pesticide usage and disturbances by humans during the bats’ winter hibernation in caves and mines. During hibernation, bats cluster in groups of up to 500 per square foot, which means a single event can destroy a large number of bats.

Fort Knox established the 1,458-acre Indiana Bat Management Area (IBMA) to manage and increase the population of Indiana bats, and later used this as one of its projects for KY EXCEL. Management activities in the IBMA include wetland monitoring/management, selective girdling of trees to create roosting sites, invasive species removal and timber stand improvement operations to provide a quality foraging habitat.

In the summer, Indiana bats roost, give birth and rear their young under slabs of loose bark of primarily dead or dying trees. Weighing only a fourth of an ounce, or about the weight of three pennies, Indiana bats are tiny, but in flight have a wingspan of 9 to 11 inches.

The maternity colony at Fort Knox has been monitored each year since its discovery in 2005, through the use of mist netting, radio telemetry and acoustical surveys. In 2006, Fort Knox initiated a project to augment summer roosting habitat through the use of installing artificial bark on standing dead trees in the IBMA near known maternity trees.

Over the course of the artificial bark project, several roost trees fell due to wind or natural deterioration. In 2012, in an attempt to create longer-lasting roosting structures, six power poles, pressure-treated only at the bottom to eliminate possible negative effects to bats, were placed in the IBMA and outfitted with artificial bark. Of the six structures, five had evidence of bat use within 60 days and all showed use within 85 days.

Jimmy Watkins, wildlife biologist at the military base said approximately $50,000 has been spent on the project. Though Fort Knox will not receive any economic value from the bat roosting project, the benefit to the continuation of the species and the environment is significant.

“The main challenge we encountered in this project was getting equipment to the site to erect the poles,” says Watkins. “Basically, it required the same equipment as power/ communication companies use to put up utility poles. Indiana bats occur in wooded areas in summer, so it can be challenging to get the roosting structures where they need to be. I recommend a partnership with a utility/communications company, or at least a cost-share conservation program with them.”

“Bats began using the artificial bark almost immediately,” says Watkins. “As many as 240 bats were observed emerging from two of the trees. Mist netting confirmed pregnant Indiana bats, indicating use as a maternity site.”

Artificial roost structures will last many years, providing quality roosting sites for Indiana bats and other species of tree-roosting bats. Indiana bats eat a variety of flying insects found along rivers or lakes, benefiting humans by feeding on insects that are considered pests or otherwise harmful to people, such as mosquitoes. Indiana bats eat up to half their body weight in insects each night, while a colony of bats can consume thousands of insects per night.

Fort Knox will continue to monitor the artificial roost structures and plans to install them in other areas of where suitable summer Indiana bat maternity habitat exists.

Joseph Yates, chief of the facility’s Environmental Compliance Branch says, “Fort Knox is grateful to KY EXCEL for opportunities to give back to the environment, making being green a wonderful experience.”

To see other photos about this fascinating Fort Knox project, click here.

For more information about the KY EXCEL program and to get ideas for projects, call 800-926-8111 or e-mail envhelp@ky.gov. Read about other KY EXCEL members and what they are doing to protect the environment at http://dca.ky.gov/Pages/ResourceDocuments.aspx under DCA Case Studies: KY EXCEL.

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