White-nose Syndrome, Bats, State Parks, and WMAs
What is White-nose Syndrome (WNS)?
White-nose syndrome (WNS) is a devastating, emergent disease afflicting hibernating bats that has spread from the northeast to other parts of the United States at an alarming rate. Since 2006, hundreds of thousands of bats across multiple states have died from WNS. The disease is named for the white fungus (Pseudogymnoascus destructans) seen on the muzzles, ears, and wings of affected bats. This disease poses a serious threat to bats that hibernate in caves. WNS has killed up to 95% of bats at individual sites. The disease causes bats to exhaust fat reserves as they hibernate, forcing them to venture from their hibernacula to forage. Unfortunately, this occurs mid-winter when conditions are extreme and bats either cannot find food or do not survive exposure to the elements.
TPWD White-Nose Syndrome Action Plan
Is WNS dangerous to humans?
While researchers are still learning about WNS, there are no known human health risks from the disease. Many researchers and cavers have worked in close contact with the fungus and as of yet there have been no reports of any human illnesses.
Does WNS occur in Texas?The Texas Parks and Wildlife Department (TPWD) has been funding researchers with Bat Conservation International (BCI) to conduct surveillance WNS since 2011. Since 2015, an additional team with Texas A&M University has been funded to intensify surveillance. These surveillance efforts did not detect WNS in Texas from 2011 through 2016. However, surveys conducted January-February, 2017 detected the fungus that causes WNS in 6 counties in the panhandle region of Texas (Childress, Collingsworth, Cottle, Hardeman, King, Scurry). The fungus was detected on three bat species; tri-colored bat (Perimyotis subflavus), cave myotis (Myotis velifer), and Townsend’s big-eared bat (Corynorhinus townsendii). Though the fungus has been detected on tri-colored bats in other states, this is the first ever detection of the fungus on cave myotis and Townsend’s big-eared bats. It is important to note that although the fungus has been detected, there has been no bat found exhibiting symptoms of WNS in Texas.
Why be concerned?
As mentioned, WNS has had devastating impacts on bat populations in the northeastern U.S. where winter conditions are extreme. Because the fungus thrives in cold environments, researchers hope that the relatively milder winters in Texas will spare our bats from the same level of devastation seen in more northerly latitudes. Additionally, research has shown that the disease affects various species differently. Some may carry the fungus, but not exhibit the disease. Some may exhibit the disease, but survive. Some are highly susceptible and succumb.
The Mexican free-tailed bats that congregate in large numbers in Texas are migratory and do not hibernate. While nobody knows for sure, researchers hope that WNS will not cause high levels of mortality in this species.
Texas, including the cave-rich Edwards Plateau region in the central Hill Country, is one of North America's most important regions for bats. Texas is home to 32 species of bats and has more public bat-viewing locations than any other state. That includes the largest known bat colony in the world, Bracken Cave near San Antonio. Our state also boasts the United States’ most famous urban bat colony, the Congress Avenue Bridge in Austin. We are concerned because of the severity of the disease and the important role bats play in our environment. Recent research shows most Texas bat species eat large amounts of agricultural insect pests, saving farmers millions of dollars. In a 2006 article in the scientific journal Frontiers in Ecology and the Environment, university researchers reported bats provided almost $1.7 million in avoided yield loss and avoided pesticide costs for cotton grown in the eight-county study region around Uvalde, Texas. Scientists say bat insect control benefits farmers into the Midwest and Canada, and that this shows the need to protect large bat colonies and promote public education and bat ecotourism.
Bats are also worth millions of dollars in nature tourism to Texas communities. According to Bat Conservation International, more than 100,000 people visit the Congress Avenue Bridge in Austin each year to witness the summer season evening bat flights, generating $10 million dollars in tourism revenue annually. Finally, Texas is a critical geographic nexus where eastern U.S. bat species overlap with western U.S. bat species. Texas is also a gateway for disease transmission from the U.S. to Central and South America. Therefore, the detection of Pseudogymnoascus destructans in Texas is worrying for the potential impact to bat populations far beyond our state’s borders.
What are TPWD and other Texas authorities doing about WNS?
TPWD employees in the Wildlife and State Parks Divisions are aware of the serious threat posed by WNS to bat populations in Texas. We have been, and will continue coordinating with partners like BCI, Universities, and private landowners to protect bats in Texas.
Is TPWD closing caves and/or locations where bats may be viewed?
- TPWD’s current plans are to continue public viewings of evening bat emergences at sites like Devils Sinkhole State Natural Area and Old Tunnel Wildlife Management Area. However, we intend to prohibit public entry into select wild caves with bats at TPWD sites. We want to prevent people from transporting fungal spores that could infect bats.
What about caves on private land?
Texas has numerous privately-owned caves that provide tours and bat-viewing opportunities to the public. TPWD is working with operators of these facilities to encourage them to take voluntary actions to prevent the potential spread of fungal spores.
What can I do to help monitor and prevent the potential to spread WNS in Texas?
Report any large-scale bat mortalities to TPWD, especially those that occur during the winter months. If you see dead or dying bats call a TPWD Kills and Spills Team or our 24-hour Communication Center (512-389-4848).
Given that WNS and other pathogens may be transmitted by humans, it is important to practice appropriate hygiene when engaged in activities such as caving or touring caves. The following link contains up-to-date decontamination protocols that address decontamination of caving equipment to control the spread of WNS in bats, but also provides guidelines that are applicable to decontamination with respect to other emerging pathogens. These protocols are intended for wildlife researchers but may be applicable to anyone who may enter a cave for work or entertainment.