Biologists have been working for three decades on a recovery project for the Illinois-endangered Blanding’s turtle, whose numbers were declining due to an increase in predators and habitat destruction.
Now the species faces a new threat: a fungal disease that eats through the shell creating a Swiss cheese effect.
Recently, three wild Blanding’s turtles in northeastern Illinois tested positive for the fungus. Chicago-area facilities that raise turtle hatchlings before releasing them into the wild also learned that water in 40% of their habitat tubs contained the fungus.
“When we first learned about the fungus, panic and fear set in,” said Gary Glowacki, manager of conservation ecology with the Lake County Forest Preserve District, where hatchlings are raised.
“Looking at the bigger picture, we’re thinking we’re fortunate we caught this early, and that ultimately this will make our recovery program stronger,” said Glowacki. He has worked with Blanding’s turtles for more than two decades.
Since the recovery program started in 1994, nearly 6,000 young Blanding’s turtles have been raised and released into northern Illinois wetlands by biologists.
University of Illinois scientists discovered the fungus — naming it Emydomyces testavorans — after testing turtles with shell disease in zoo collections. They later also confirmed a wild population of endangered western pond turtles in Washington state also had the disease caused by the fungus. The shell disease can lead to infection and premature death.
Though disease-causing agents like fungi and viruses normally appear in the environment, “more fungal diseases recently have been showing up in wildlife,” said Matt Allender, director of the wildlife epidemiology lab at the University of Illinois’ veterinary diagnostic laboratory.
The reasons are unclear, but it could be due to climate change, deteriorating ecosystems, loss of habitat and declining populations.
“A study published 10 years ago found that of all the emerging diseases in plants and animals, 75% were caused by fungus,” Allender said.
In Illinois, a fungus similar to the one found in the turtles is affecting other reptiles, including the state-endangered eastern massasauga rattlesnake. The species has experienced a 90% mortality rate at its last stronghold near Carlyle Lake in southwestern Illinois, Allender said. Many species of snakes in Illinois, including milk snakes in Lake County, have tested positive for the fungus.
White nose syndrome, caused by a fungus, has killed millions of cave-hibernating bats across the eastern United States since the early 2000s. It has also ravaged an Illinois population in LaSalle County, said Brad Semel, endangered species recovery specialist for the Illinois Department of Natural Resources.
Scientific articles are reporting a rise in fungal diseases. Yale University School of the Environment reported in 2016 that an “unprecedented global wave of virulent fungal infections is decimating whole groups of animals — from salamanders and frogs, to snakes and bats.” An article published in American Society for Microbiology in 2020 cited an increase in fungal diseases in plants and humans.
In May, another fungus killed endangered piping plover Monty, a popular fixture at Montrose Beach for the three previous summers. But that fungus is different from the kinds found in turtles, snakes and bats, said Karen Terio, chief of the University of Illinois Zoological Pathology Program, who works with Allender.
In the case of globally imperiled species like the Blanding’s turtle, diseases can be devastating since the animal’s numbers have already significantly declined, Allender said.
After U. of I. pathologists found the fungus in the zoo animals, they decided to test the Blanding’s turtles in Illinois even though they weren’t showing any signs of disease. Allender said they caught the fungus early and that gives them hope for preventing an outbreak.
“All the stakeholders are on the same page. We’re working to save the turtles,” said Allender. His team tests turtles, snakes and other reptiles for signs of disease in a state program called Wellness of Wildlife.
This summer, biologists plan to test for the fungus in the wetlands where the Blanding’s turtles live in DuPage, Lake, Cook, Kane, McHenry, Will, Lee and Ogle counties.
Semel said the Blanding’s recovery program, which he leads, has “literally come to an immediate halt. We have to better understand our actions to see if it could jeopardize these populations, if we are introducing this emerging threat we were not aware of.”
Blanding’s turtles historically lived across the northern two-thirds of Illinois.
“Conversion of natural lands through urbanization and agriculture has greatly reduced available habitat such that in most cases, remaining Blanding’s turtle populations are small and highly fragmented by roads and development,” Semel said.
The species was listed as endangered by the state in 2009 because it had declined significantly in abundance and distribution and was dependent upon a rare and vulnerable habitat.
“This is a species that needs sedge meadows and high-quality wetlands that were historically present. They need uplands to lay eggs, shallow sedge meadows to forage in summer and deeper water for overwintering,” Semel said.
Only six sites — in Lake, McHenry, Grundy, Carroll and Whiteside counties — are left in the state where the population is viable, according to Semel. The species’ range also extends to New York, Wisconsin and Minnesota. The U.S. Fish and Wildlife Service is assessing whether to list the Blanding’s turtle as federally endangered.
Several decades ago, researchers in northern Illinois discovered that when female Blanding’s turtles laid eggs, predators like raccoons, whose numbers are growing in the state, immediately dug them up and ate them.
“There wasn’t any successful reproduction going on,” Semel said. They weren’t finding any young turtles that could, at the age of 10, start reproducing.
The head-start project began in McHenry and DuPage counties. Biologists don wading boots and collect females at egg-laying time, being careful not to harm them. They bring the females to a lab to lay eggs and then return them to the wild. Female Blanding’s turtles take no part in rearing young — they lay the eggs and leave — so taking the eggs does not harm them, Semel said.
Then the biologists raise the hatchlings until the shells are hard enough and the young are big enough to be released into the wild without being preyed upon. Today, turtle-hatching facilities are located at the Peggy Notebaert Nature Museum and Shedd Aquarium in Chicago, Brookfield Zoo, Cosley Zoo in Wheaton, the McHenry County Conservation District and the Lake County Forest Preserve District.
“We’ve been having positive results year after year,” Semel said. “The survivorship is increasing, and turtles hatched in captivity are starting to breed in the wild. We thought if we’re this successful, we can start adding to some other populations in Illinois.”
That’s not going to be happening, at least for now.
Terio said the fungus affecting the Blanding’s turtles is the same that caused shell lesions in aquatic turtles in zoological collections across the nation and in the state of Washington.
“There are pockets of the western pond turtle population where over 80% of them have shell disease,” Terio said.
Allender said his team has been testing Blanding’s turtles for different diseases for the past six years. In winter, they decided to test samples they had taken from turtles in the wild over the past few years for the newly emerged fungus.
“We didn’t want the Blanding’s turtle to go the way of the western pond turtle,” he said.
The Blanding’s turtle hatchling facilities are now establishing biosecurity protocols such as requiring employees to work with the turtles known to be negative for the fungus before working with those that are positive and to use gloves before handling the turtles.
“The overarching principle of conservation ecology is: Do no harm,” Glowacki said. “It’s a scary thought to think you could be doing more harm than good. We’re at this crossroads. How do we continue to reap the benefits of all of our efforts? It adds a new wrinkle.”
Members of the public who have paid to adopt a turtle in the Lake County Forest Preserve District program have been notified, and many agreed to donate funds to outbreak prevention, Glowacki said.
Terio said drugs have been identified that could treat the turtles with the fungus.
“But the question is how do you deliver that drug to a turtle? Can we do it as an implant or as a slow-release capsule?” she said.
Her department also is working on other strategies, including filtration systems that use different wavelengths of light to target the fungus, much like a filter on a fish tank.
“We are looking to see which of these methods of filtration might be best not only to reduce the fungus levels but also to promote overall turtle health,” Terio said. But they need to be careful not to create a completely sterile environment, which Terio said is “often not a healthy one.”
The Shedd Aquarium has been studying how head-start projects to help endangered turtles may best be conducted to avoid spreading the fungus. The aquarium has eight western pond turtles from the Washington state recovery program, which is very similar to the Blanding’s turtle program in Illinois.
Allender said his team has been working with a Blanding’s turtle that came from a homeowner who was illegally raising it in a pond in the backyard. That turtle tested positive for the fungus.
“Within the last two months, we got our first negative test on the turtle we’ve been treating for eight or nine months,” he said. Treatments have included drugs, inhalers and other methods, but further testing is needed to see what works best, according to Allender.
It could be a long time before a treatment will easily be available for Blanding’s turtles in the wild, he added.
“I’m concerned about the options for treatment. We have developed novel treatments for snake fungal diseases, lowering mortality and disease rate. But turtle shell fungus disease is a lot more problematic,” Allender said.
Terio said biologists are wondering, “Why are we now all of sudden starting to see a number of these different fungi popping up? All of them have come out in the last couple of decades.”
The reasons could include climate change and degraded ecosystems, and humans are responsible, Terio said. “It’s our obligation to do all we can to help the wild creatures affected by these changes,” she said.
The case of the Blanding’s turtle also shows the complexities of helping endangered species recover.
“It’s such a multifaceted approach,” Semel said. “People used to think, we won’t hunt them anymore. That was the most direct approach. Then we realized they need a place to live. Let’s do habitat management. Then you realize, we have climate change and the timing can be off for some species. For example, Karner blue butterflies are hatching before their food is available.
“Now we’ve added health assessments. … Diseases will be a really critical component in understanding how to recover an endangered species,” Semel said.
Sheryl DeVore is a freelance reporter.