Invasive Cuban treefrog extends its presence in Florida
An invasive amphibian species, already in Gainesville, has started to invade the backyards and toilets of residents in north Florida communities.
The species was found in the Florida panhandle in January and has invaded areas of Georgia and Louisiana. Isolated sightings have also been reported from 29 other states and some Canadian provinces.
Recent scientific research predicts that, as the climate warms, most of the Southeastern U.S. will be suitable for Cuban treefrogs to inhabit. This data is taken from an unpublished report written by Steven A. Johnson, professor of herpetology, concerning the environmental and infrastructural impact of these invasive amphibians.
Cuban treefrogs are a native species of Cuba, the Cayman Islands and the Bahamas that came to the United States, more specifically Florida, in the 1920s. This species has had over a century to invade Florida ecosystems and negatively impact both human infrastructure and native species.
These frogs are attracted to dense forests and woodlands, and they are especially prone to dehydration, which is why they prefer moist and swampy environments. While this species loves to inhabit natural spaces, they are even more commonly found near human development and suburban neighborhoods. Cuban treefrogs usually hide around homes and buildings, and they are most active at night during high humidity levels.
Cuban treefrogs are the cause of much ecological damage to Florida ecosystems. These amphibians have a varied diet of snails, millipedes, spiders, and other insects, but are also predators of native Floridian frogs. Cuban treefrogs often eat native species as well as lizards and small snakes. The native squirrel treefrog is especially susceptible to predation from the much larger and more competitive Cuban treefrog species.
Besides being predators to many of the native species that are part of Florida’s environment, these frogs also pose a problem related to the quality of living for residents in the Gainesville and northern Florida areas. These frogs not only seek shelter near human infrastructure but also thrive in human-inhabited areas. Because homes and buildings provide ample shelter that promotes an abundance of food sources, scientists have seen a significant increase in the populations of the invasive species.
Cuban treefrogs leave their feces on walls and other surfaces that are not only unattractive but unsanitary as well. They also can enter people’s homes through open doors or windows, inadvertently brought inside on a house plant, or through a home’s plumbing system.
The frogs can end up in your bathroom. According to an unpublished report described “unsuspecting people … open[ing] the lid to their toilet only to find a bug-eyed Cuban treefrog staring up at them.” This problem could escalate to clogged drains and costly plumbing issues.
These creatures can also cause economic problems in the surrounding community. They are known to invade transformer boxes and electrical systems that damage the equipment. This can result in expensive maintenance costs for electrical utility companies.
Cuban treefrogs can be a health threat to people, animals and pets. When they feel threatened or harassed, Cuban treefrogs will secrete a toxin that is irritating to humans. The toxin can cause a burning and itching sensation that lasts for over an hour.
If the frog is ingested by animals or pets, the toxin can irritate the mouth, which causes the production of excessive saliva. While the toxin is not fatal to animals, there have been isolated reports of pets developing seizures as a reaction to the toxins.
Despite their harmful impact, Cuban treefrogs have one weakness: freezing temperatures.
“They tend to not tolerate freeze very well,” David Blackburn, curator of herpetology at the Florida Museum of Natural History, said.
Professor of herpetology Steven Johnson is optimistic about future weather patterns.
“I get a few emails about people seeing dead Cuban treefrogs, but I just got an email the other day about someone seeing one alive in Gainesville," Johnson said. "Again, they’re still persisting. The cold might knock back their populations a little bit, but it didn’t get rid of them. This next spring and summer, we’ll tell for sure whether there are frogs out there in the panhandle.”
There are still ways in which Cuban treefrogs can survive.
“Freeze tolerance is something that some species of amphibians have but not all. Because behaviorally [Cuban treefrogs] tend to be associated with humanly created structures that are warm, they can regulate their temperatures,” Blackburn said. “So, even if it gets quite cold, they can seek out places in the environment that humans create to stay warm.”
There are still issues with Cuban treefrogs in the Gainesville community and even on campus. There are no university or government programs that are established for the purpose of removing this invasive species.
“They can basically lay eggs and have tadpoles in pretty small ephemeral pools and puddles. We have that all over campus,” Blackburn said. “You won’t find a lot of other frogs breeding in those same places. But you can find some puddles on campus where Cuban treefrogs will colonize.”
There are some things that homeowners and residents of Gainesville can do to help combat the spread of Cuban treefrogs. The best way is to report any sightings to Steven Johnson or to EDDMapS, an online mapping system for invasive species in the U.S.
Otherwise, homeowners can try to euthanize the frogs themselves by placing them in a refrigerator for three to four hours and then in a freezer for about a day.
More information can be found on the UF Institute of Food and Agricultural Sciences website.
The next time you need to go to the bathroom, make sure to check inside your toilet for those bug-eyed amphibians before it jumps out at you.