The fungus known to cause White-nose Syndrome (WNS), a disease that has decimated hibernating bat populations in the United States and Canada, has been discovered for the first time in Texas.
The fungus Pseudogymnoascus destructans (Pd) was detected on three species of hibernating bats in northern Texas: the cave myotis, Townsend’s big-eared bat, and the tri-colored bat. This is the first discovery of Pd on the cave myotis and the first detection of the fungus on western populations of Townsend’s big-eared bats – two bat species with distributions extending further into the west.
“This is devastating news for Texas, and a serious blow for our western bat species,” says Mike Daulton, Executive Director for Bat Conservation International (BCI).
Katie Gillies, Director of Imperiled Species for Bat Conservation International added, “We have been surveying hibernating bats and monitoring for the arrival of Pd for the Texas Parks and Wildlife Department (TPWD) since 2011. At this early stage of detection, we have not observed any visible signs of the disease on any bats in the state, such as white fungal growth on the nose and wings. Detecting the fungus when it first arrives gives us a chance to take action and try to minimize the impacts from White-nose Syndrome on our Texas bats.”
The fungus was detected in six Texas counties from samples collected by biologists from BCI and Texas A&M University (TAMU). The cave and bat samples collected in Childress, Collingsworth, Cottle, Hardeman, King, and Scurry counties were analyzed by researchers at the University of New Hampshire as part of University of California at Santa Cruz, TAMU, and BCI research projects.
“We need to expand our targeted surveillance to get a better understanding of the distribution of the fungus,” explains Gillies. “We will also be reaching out to landowners and the community to help protect bat roosts and emphasize decontamination to reduce the likelihood of an accidental spread of the fungus to a new location.”
White-nose Syndrome has been rapidly expanding westward since its discovery in New York in 2007. Millions of bats have been killed by the disease, with population declines greater than 90% in some states.
Texas, with 32 bat species, has the greatest diversity of bat fauna in the country. The state is also home to the famous roosts of Mexican free-tailed bats at the Ann. W. Richards Congress Ave Bridge in Austin and Bracken Cave, one of the largest bat colonies in the world, near San Antonio. However, Mexican free-tailed bats do not hibernate all winter and may not be highly susceptible to the disease.
“While we are cautiously optimistic that Mexican free-tailed bats will not be heavily impacted by the disease, we do have serious concerns for hibernating species, such as the cave myotis, that often share their roosts,” says Winifred Frick, BCI Senior Director of Conservation Science.
Texas is the most eastern edge of the distribution for the cave myotis, with the species being found throughout southwestern USA and into Mexico. The discovery of the fungus in Texas is significant on a national scale as biologists are concerned that the spread of Pd into western states will be exacerbated as this and other western species are exposed.
“The detection of Pd in Texas comes on the heels of last week’s announcement of White-nose Syndrome being confirmed in Nebraska. This emphasizes the need for us to not only increase our surveillance but also our research efforts to identify and develop tools to improve survival for bats exposed to the fungus. Although there is no known treatment for White-nose Syndrome, we are actively working on research that may prove effective,” she explained.
Working to minimize the impact of White-nose Syndrome is not only important for the future of Texas’s bats but its agricultural industry as well. Studies have shown that the value of ecological services by bats to agriculture is $1.4 billion dollars annually in Texas alone. This value includes reduced crop loss from insect pests, reduced spread of crop diseases, and reduced need for pesticide application.