White-nose syndrome has killed 5.5 million bats so far
Read more about white-nose syndrome in the Summit Voice archives
A fungal pathogen that has wiped out bat populations across the eastern third of the U.S. has now been found in Texas, according to state wildlife officials, who documented the fungus for the first time on two new bat species: the cave myotis and a western subspecies of Townsend’s big-eared bat.
White-nose fungus first emerged in 2006 in New York and his since spread into 30 states and killed at least 5.5 million bats. Wildlife conservation advocates said the recent announcement from is a biological disaster, considering the potential risks to huge, world-famous bat colonies that thrive in unique cave ecosystems in the state.
No sickened or dead bats have been found in Texas yet, but biologists expect they will start showing up within the next two to three years if the disease follows the same pattern as before. There are now 30 states and five Canadian provinces where the disease has been reported. The fungus has been found in Oklahoma, Mississippi and now Texas, but no incident of the white-nose disease has yet been documented.
The bat disease has afflicted seven bat species so far. With the fungus now reported in Texas and discovered for the first time on two western bat species, bats in the West are being hemmed in on two sides by the advancing lines of the disease. Scientists do not know how western bat species, such as the cave myotis and Townsend’s big-eared bat, will fare.
Most bats in North America are voracious hunters of insects, including those that attack farm crops and timber stands. Scientists have estimated the economic value of insect-eating bats to American agriculture at $22 billion annually. Bat guano is essential to the survival of extremely rare cave organisms like cave salamanders and fish.
The cave myotis and Townsend’s big-eared bat have large western ranges, and the discovery of the fungus on them marks a turning point in the westward spread of the bat malady. Just last week white-nose syndrome was announced for the first time in Nebraska. Last spring the disease was reported for the first time on the West Coast, in Washington state.
Many leading bat biologists have emphasized precautionary measures, such as cave closures and site-specific caving gear requirements, as the best management responses. The Center for Biological Diversity filed a petition in 2010 to close all caves and abandoned mines on federally controlled lands in the lower 48 states, keeping all but essential human activity out of caves. Such closures also would reduce disturbance of vulnerable hibernating or roosting bats.
White-nose syndrome has resulted in dramatic declines among several bat species. The disease has caused mortality rates ranging up to 100 percent among bats in affected caves. The northern long-eared bat, tricolored bat, little brown bat and Indiana bat are the hardest-hit species.
The U.S. Fish and Wildlife Service listed the northern long-eared bat as a threatened species in 2015, primarily because of the ravages of the disease. The Service is currently considering protecting the tricolored bat and the little brown bat, both of which have also drastically declined. The Indiana bat was listed as endangered decades prior to the arrival of white-nose syndrome, but the bat disease has exacerbated its tenuous hold on survival.
White-nose syndrome is passed from one bat to another, or from the cave environment to bats, but it also likely spreads when people inadvertently carry it from one cave to another on their shoes, clothes or equipment.
Learn more about white-nose syndrome in this FAQ.