CONSERVING VULNERABLE POPULATIONS
The value of bats to the North American agriculture industry is roughly $53 billion per year, according to the U.S. Geological Survey. The estimates include the reduced costs of pesticide applications that would otherwise be needed to suppress the insects consumed by bats. Some bat species can eat the equivalent of more than 70 percent of their body mass in insects per night. In an hour, a single little brown bat can eat up to 1,000 insects such as mosquitoes that can carry dangerous diseases, including the West Nile virus.
Bats are also pollinators. Long-nosed bats, which inhabit the dry portions of the North American tropics from El Salvador to northern Mexico, are the primary pollinators of the agave plant, from which tequila is derived. Through pollination, the bats promote the genetic diversity and vitality of wild agave. So, without bats, there might be no tequila.
In addition to the important role bats play in insect and pest control, pollination and seed dispersal, soil fertility, and nutrient distribution, they are also important prey for higher-level predators, such as owls, hawks, raccoons and snakes.
As a researcher, Loeb has been studying bat ecology since 1999. In partnership with scientists from the National Park Service, U.S. Fish and Wildlife Service, U.S. Geological Survey and Canadian Wildlife Service, she created the North American Bat Monitoring Program (NABat).
NABat’s mission is to identify priority bat species for conservation and measure the success of conservation efforts. In 2015, NABat published A Plan for the North American Bat Population that prescribes four approaches wildlife ecologists and land managers can use to gather data to assess changes in bat distributions and abundances: winter hibernaculum counts, maternity colony counts, mobile acoustic surveys along road transects and acoustic surveys at stationary points.
“The disease [white-nose syndrome] has progressed faster than I thought it would,” Loeb says. “It’s only going to get worse and continue to spread until a treatment or cure is found. But we’re continuing to work here on campus and with our partners to understand the spread of this deadly disease and to minimize its impacts.”
Currently 40 states and all 10 Canadian provinces participate in the NABat survey and data collection system.
Last year, Loeb and Jachowski performed a survey of bats at 11 sites in the Sumter and Chattahoochee national forests. They also deployed acoustic technology to record bat calls in an effort to document species variety, as they are doing in Stumphouse Mountain Tunnel. They then compared their findings to data collected at the Sumter and Chattahoochee sites in 2006, the year the deadly disease arrived in the U.S. The survey results were disheartening.
“Bats affected by white-nose syndrome have vanished from some of the survey sites,” Loeb says. “It can take years to rebuild bat colonies, if they can even rebuild at all. Bats don’t reproduce quickly. Most species only have one pup per year, and many of those die.”
As a Clemson University wildlife biology graduate student, Ben Neece led the first South Carolina statewide bat survey as part of the NABat project. The project was funded by the South Carolina Department of Natural Resources.
The goal of the study was to check the efficacy of the NABat survey for South Carolina bat populations, understand the factors affecting detection success and assess environmental factors influencing populations.
Neece used both mobile and stationary surveys to collect bat echolocation sounds from 38 survey cells across South Carolina. The survey sites were chosen for an array of factors, including habitat variety, maximum bat species diversity and low clutter that would interfere with recording.