Delaware bat decline tracked with grant money
Wildlife scientists get $22,693 from the U.S. Fish & Wildlife Service to monitor Delaware bat population
- White-nose syndrome is a bat disease caused by a fungus.
- It has caused mass mortality among several bat species in the region.
- Thirty-four states and the District of Columbia also are getting grants.
Amid the damp, twisting corridors at Fort Delaware State Park, wildlife scientists track the last known stronghold of wintering bat populations in the state.
This week they were awarded another $22,693 from the U.S. Fish & Wildlife Service to continue population monitoring both during hibernation in the winter and during the early summer as maternal colonies of bats are raising their young.
The grant is part of a $1 million national effort to control the spread and learn more about white nose syndrome, a bat disease that is caused by a fungus and has caused mass mortality among several bat species in the region.
Delaware doesn't have many caves, the typical habitat where bats spend winter. There is just one natural cave in the state.
But “the cave-like conditions at Fort Delaware provide ideal temperature and humidity levels for bats to hibernate and for the fungus that causes WNS to survive,” said state wildlife biologist Holly Niederriter, who heads the Division of Fish & Wildlife’s bat monitoring efforts. White-nose syndrome "continues to be a threat to bats that hibernate there. Our winter surveys at the fort have shown a steady decline in bat numbers, with 40 percent fewer bats counted in 2015 compared to 2013.”
There could be other factors at play at the Fort site, but the decline probably is caused by the fungus, she said.
Bat species that hibernate can contract white-nose syndrome. These include the little brown, big brown, tri-colored, northern long-eared and eastern small-footed bats – all of which were once found in Delaware. Northern long-eared and little brown bats were added to the state endangered species list in 2014. In addition, the northern long-eared bat was added to the federal endangered species list in last year.
“Bats are important to Delaware’s ecology, feeding on millions of insects, including mosquitoes, beetles, moths and agricultural pests," said Davis Small, state environmental secretary. They are "also helping us ward off potential threats to public health and the food supply.”
Thirty-four states and the District of Columbia also are getting grants.
While winter hibernating colonies are a key concern, state biologists, working with citizen volunteers, see declines in summer monitoring at the maternal colonies – typically in old barns and buildings throughout the state.
Delaware used to have little brown bats.
"Now they are completely gone," she said. "All of our small bats are going away."
Among the species rarely or never caught during summer monitoring in recent years are little brown bats, northern long-eared bats and tri-colored bats, she said. Big brown bat populations continue to hang on in the state.
Niederriter said that some of the federal grant money coming to Delaware will be used for outreach and education because state officials don't want visitors to the popular Civil War fort to accidentally track the tiny fungus spores to another state or region that is fungus-free.
Dozens of areas within the Fort Delaware complex tested positive for the fungus that causes the bat syndrome.
When bats contract the fungal disease it causes white areas on the nose, wing tips, tail and ears. It can lead to death.
It was discovered 10 years ago in New York. Delaware's first cases were found in 2012 among hibernating populations at Fort Delaware and Fort DuPont. The fungus in now found in 29 states and has been linked to an estimated 5.7 to 6.7 million bat deaths.
Money for the latest monitoring work in Delaware comes from the U.S. Fish & Wildlife Service Endangered Species Recovery and Science Applications program.
Niederriter said the grant will allow continued population monitoring and population recovery strategies.
In addition, Niederriter said, it will help prevent the spread of the fungus to other states.
“We’ll also be using the funding to continue our efforts to educate visitors at Fort Delaware about bats " and white-nose syndrome, she said.
"The focus is on increasing survival of bats," where the fungus is already established, said USFWS Northeast Regional Director Wendi Weber. "It’s also on limiting the spread, and where the disease has not been discovered, it’s on preventing the arrival" of white-nose syndrome.
Reach Molly Murray at (302) 463-3334 or email@example.com. Follow her on Twitter @MollyMurraytnj.