Peter August, URI professor of natural resources science, began tracking the population of little brown bats at the campus in 1982, and he typically counted about 150-175 bats flying out of the barn at dusk during most years. The Woodvale barn is a maternity colony of little brown bats and consists of females and their young born in early summer. The population declined dramatically beginning around 2010, and this month he counted just 49 bats exiting the barn.
“The decline is almost certainly due to white nose syndrome, the deadly disease that is killing bats in the caves they hibernate in,” said August. “Woodvale Farm is one of the only places in Rhode Island where data had been collected on bat numbers prior to the disease outbreak, and this information is helping us understand the impact the disease has had on bats in the state.”
White nose syndrome is caused by a fungus native to Europe that scientists believe irritates the bats into waking up from their winter hibernation. When the bats become active at a time when food is unavailable, they use up their storage of fat, which leads to their death. The little brown bats that breed in Rhode Island hibernate primarily in caves and mines in New Hampshire, Vermont and Upstate New York, which is where the first outbreak of white nose syndrome began in 2006.
“We don’t have firm proof that white nose syndrome has caused the decline in our local bat populations,” said August. “But I can’t imagine any other factor that would cause such a precipitous decline so quickly, especially when you consider the high mortality rates of bats in the caves and mines infected with the fungus. Over 90 percent of the hibernating bats can die in the span of a few years in a single cave. It is believed that more than six million bats in the northeastern U.S. have died in the past six years. There is a strong correlation between when white nose syndrome started and when Alton Jones bats declined.”
Charles Brown, a wildlife biologist for the Rhode Island Department of Environmental Management, has been carefully tracking bat colonies on private property in Little Compton, Narragansett, West Greenwich, Coventry and South Kingstown for two or three years, and all have declined from historic estimates provided by the landowners.
“The Woodvale Farm barn is the best documented and likely the most dramatic example of how white nose syndrome has affected bats in the state,” said Brown.
When Brown counted the bats at the Alton Jones Campus colony in June, he observed just 26 bats emerging from the barn. He said that the increase to 49 bats that August counted a month later probably represents baby bats born this summer that have just begun to take flight.
“Now is the time of year that the young are beginning to wean,” August said. “It is difficult or impossible to age bats as they emerge from the barn. All you typically see is a dark-colored bat quickly darting away from the building.”
The W. Alton Jones Campus is celebrating its 50th anniversary this year. In addition to bat research, the campus has been the site of dozens of research projects through its history, including studies of salamander migration, fish populations, eels, lilac blooms, soil moisture, caddisfly larva, and colors that elicit avoidance behavior in mallard ducks. The 24-hour BioBlitz event in 2004, sponsored by the Rhode Island Natural History Survey, counted 1,004 species of wildlife living on the campus. The undisturbed nature of the campus makes it an ideal site to study plants and wildlife in pristine ecological conditions.