The Depths We Go… to Study Bats

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Bat Conservation International, TPWD Nongame and Rare Species Program, and Texas A&M University biologists and volunteers during bat surveys in the Texas Panhandle.

Texas bats are in danger. White-nose syndrome (WNS), a devastating fungal disease, is almost here. The disease is caused by a fungus that thrives in the cold environments where bats hibernate. Hibernating bats with WNS often display white fungus on their noses and other hairless parts of their bodies, including their wings.The fungus isn’t always visible to the naked eye, however, and usually is not seen on bats found flying or dead outside of their hibernacula or at their summer roosts.

White-nosed syndrome kills bats during hibernation by agitating their skin which causes them to wake up and preen. This expends their extremely limited energy reserves needed to sustain them for the entire winter and can eventually lead to starvation.

White-nosed syndrome was first discovered in New York in 2006 and has since spread westward towards Texas at a rate of about 200 miles a year. The disease is responsible for the deaths of nearly six million bats across North America. It is now just 170 miles from the Texas border in Arkansas and was just recently found in eastern Oklahoma. White-nosed syndrome does not affect humans.wns_map_20160216.jpg

Texas hosts 32 species of bats, more than any other U.S. state. Three species of Texas bats are known to be impacted by WNS and five others have been found with the fungus but exhibit no disease symptoms. The effects of WNS on the remaining 25 bat species in Texas are not known.

Many bats can live for 20 years or more and are very slow to reproduce. Stressors, such as introduced diseases like WNS, can result in significant population declines and push species towards regional extirpations or even extinction. The loss of bats due to WNS could have wide-ranging impacts to the ecosystem services provided by these night-flying, insectivorous mammals. From a human perspective, bats provide billions of dollars in pest control to agriculture annually through their insect feeding activities. Loss of bat populations would likely raise agricultural costs and increase pesticide applications.

Fortunately, the Mexican free-tailed bats, which roost in the millions in Bracken Bat Cave, Old Tunnel State Park, and the Congress Avenue Bridge in Austin, migrate instead of hibernate during the winter months. While this will likely shield them from the worst effects of the disease, Mexican free-tailed bats could still spread the fungus to more susceptible species across the western U.S.

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Biologist examines a bat in a Texas Panhandle cave.

The Nongame and Rare Species Program at Texas Parks and Wildlife Department is partnering with Bat Conservation International and Texas A&M University to monitor bat populations and the spread of WNS. In early February 2016, biologists from both groups, along with some dedicated volunteers, met in the Texas Panhandle (Childress County) to test bats in several caves for WNS. Caves in this region of Texas are thought to contain environmental conditions (cold, humid) conducive to WNS infection.

Biologists searched caves for bats and when found, counted and swabbed individuals to test for WNS infection. The biologists are currently looking for additional caves in northern Texas to sample for the disease. This work is being supported by a grant through the U.S. Fish and Wildlife Service’s White-nose Syndrome Grants to States and the Pittman-Roberson Grants Programs. For more information about this disease visit White-nose Syndrome.org.

 

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