In Alachua County, the most problematic neighbor is likely a frog.
Most frogs nationwide are suffering from habitat destruction, climate change and pollutants. But in Alachua County, the most significant threat to native frog species is the Cuban tree frog.
The Cuban tree frog arrived in Florida in the 1920s, clinging onto cargo ships as they departed from Cuba and the Bahamas. Since then, these frogs have not been stealthy. From hanging out in bird baths to eating native frogs, these Cuban tree frogs are anything but nondisruptive.
“You don’t want to think that we could lose all of our native frogs,” said Aubrey Greene, research associate for the Florida Fish and Wildlife Conservation Commission.
The problem with this invasive species begins with their aggressive breeding habits. Greene said that Cuban tree frogs are very “opportunistic breeders” meaning you can often find tadpoles in bird baths, buckets and urban retention ponds.
The consumption of other species begins early. As tadpoles, these Cuban tree frogs will eat other native tadpoles and push them out of habitats. Once the tadpole becomes a frog, these Cuban frogs assert even more dominance in the ecosystem. But the secret to their success is also, in part, choosing habitats that have no competition.
“They find a lot of places to hide around our houses that they might not necessarily find as easily in the natural environment,” Greene said.
Cuban tree frogs will usually be found in urban areas. They are attracted to light, and the bugs that congregate at these artificial light sources. For them, these bugs are an easy and convenient food source.
Unlike most native frogs, Cuban frogs will not spend most of their time in natural habitats – a relief to native frogs and an annoyance to urban households.
Cuban tree frogs will sometimes come inside houses, choosing to pop up in toilets or sinks when you least expect it. Urban houses prove a luxurious destination for Cuban tree frogs looking to make a home.
“They can find just in one yard a bountiful amount of food, refuge and breeding sites,” Greene said. “Just in one person’s yard.”
But this makes them even harder to manage. It’s difficult to regulate a species that is hiding in the safety of neighborhood palm trees.
“We have all these animals we’re sharing our lives with and scientists can’t get in our backyards,” said Jade Salamone, conservation education curator at the Santa Fe College Teaching Zoo. “They don’t have the permission to get on everyone’s private property.”
FrogWatch USA is one way for scientists to know what’s going on behind the fence. A citizen science program, it relies on community members to collect localized data on frogs and toads. It launched in 1998 and has expanded to over 151 chapters nationally, reaching Alachua County in 2011.
The Santa Fe College Teaching Zoo operates the local chapter, which teaches volunteers the different frog calls of the 22 common species in Alachua and Bradford counties so they can record local frog populations. This helps scientists know what species are thriving and whether they are native or invasive.
In 2020, out of 35,500 assessed species threatened with extinction, about 40% of them were amphibians.
Frogs are a great indicator species of the environment, making them particularly valuable to watch. They have an important role in the food cycle, which can inform scientists about predators and prey in the ecosystem. Frogs also have absorbent skin which allows scientists to test the acidity in the water.
“They live on land and water,” Salamone said. “So, if you have contaminated land or water, they are going to reflect the health of that ecosystem.”
Trainees must pass an assessment to become a certified FrogWatch volunteer. Salamone said that out of the 40 or 50 people that show up to training courses, usually only about 10 go through with the certification. Therefore, the three-hour training is also promoted as a way of educating people about local wildlife.
Daniel Dunn is a former middle school environmental teacher and a prospective volunteer who is studying to take the FrogWatch certification assessment.
“It’s kinda fun to be able to hear a frog and go, I know what that is,” Dunn said.
But studying frog calls is not the only way community members can help protect native frogs.
Dr. Stephen Johnson is an associate professor at the University of Florida who researches Cuban tree frogs and potential control methods. His lab’s website gives instructions to citizen scientists on how to humanely euthanize them.
Euthanizing them helps control their spiraling reproduction in an environment that already sees pressure on native frogs due to habitat loss and climate change. In Florida, it is illegal to rerelease Cuban tree frogs into the environment.
Johnson suggests the most humane way to euthanize a Cuban tree frog is to apply a product that has 20% benzocaine in it, such as burn sprays, to its back and belly, which will render the frog unconscious. Once the frog is unconscious, place it in a plastic bag and put it in the freezer overnight. The frog should be dead in the morning.
While the website notes the fascinating qualities of Cuban tree frogs, it says the disruption to the current native frogs and urban populations means they do need to be managed.
“It’s about keeping common species common,” Greene said.