When invasive species start obliterating a habitat, humans in the area often seek to eradicate the invader. People set up nets, lay traps, and aim firearms at the offenders.

Sometimes, these efforts aren’t enough, particularly if the invasion is widespread. More creative means are needed, and in recent years, ecologists have turned to novel ways to stop destructive species.

Identifying Invasive Species

The Federal government defines invasive species as any type of harmful “alien species” that are introduced to an area through human activity. They can be animals, plants, or pathogens.

Sea lampreys, for example, are an Atlantic fish that made their way into the Great Lakes through canals. They preyed upon native species like trout and whitefish, and by the 1950s, the Great Lakes fishing industry was nearly ruined. Eradication helped reduce the lamprey by 90 percent. 

Read More: The Familiar Plants and Animals That Invaded America’s Landscape

In the 1990s, conservationists began considering how trained dogs could be more effective than their human counterparts in identifying invasive species.

“Everyone knows that dogs have an amazing sensitivity for low odor detection. But what a lot of people don’t know is that dogs are also good at discrimination and telling the difference between two similar odors,” says Pete Coppolillo, the executive director of Working Dogs for Conservation in Missoula, Montana.

Conservation dogs can distinguish between a healthy sheep and one infected with an invasive pathogen. They can identify a brook trout from a rainbow trout. They can even sniff out seeds and distinguish whether they are invasive.

Read More: 10 Invasive Species You Can (and Should) Eat

Using Detection Dogs to Prevent Invasive Species

Coppolillo’s organization takes shelter dogs and trains them into conservation dogs. They also work with dogs that have been trained for other jobs. One of their dogs was a military cadet meant for Delta Force.

“But he didn’t like to bite,” Coppolillo says. “That works for us.”

The organization has trained more than 200 dogs to sniff out specific invasive species. One dog, Sami, is a Shibu Inu who works biosecurity to keep rodents out of South Georgia and the Sandwich Islands.

Any ship that intends to even be in the territorial waters must first stop in the Falkland Islands for a Sami sniff-down. Coppolillo says that Sami is 60 times faster than humans who attempt his job. In one training session, a live rat was contained and hidden on a giant cargo ship.

“Five people searched that boat for an hour and gave up; Sami found it in five minutes,” Coppolillo says.  

When Sami finds a rat or other potential invader, he is trained to alert the humans. They manage the rat removal so Sami doesn’t have to sully his paws, Coppolillo says.

But in other eradication attempts, scientists have considered novel ways in which the invasive species was made into prey.    

Read More: Working Detection Dogs Help Conservation Researchers Sniff Out Data

Toad Busting in Australia

In the 1930s, an Australian man traveled to Hawaii and brought back about 100 cane toads (rhinella marina). He released the toads with the hope they would chomp on crop-ruining insects. Instead, these poisonous toads proved deadly to the native species that tried to prey on them.

At first, many Australians were kind of cool with the cane toad taking out their most feared predators like crocodiles and snakes. But by the 1970s, Australia’s native animals were dying off at an alarming rate after coming into contact with the toad’s toxin. 

Some locals turned to “toad busting” events in which volunteers caught toads for officials to euthanize. At times, this helped drop the toad population by 27 to 48 percent.

But it wasn’t enough because the infestation was widespread. Cane toads can hop as far as 1.2 miles in one night, a distance that many amphibians never cover in a lifetime. 

In the early 2010s, scientists were hopeful the meat ant (iridomyrmex reburrus) could take out the toad because it was unbothered by its toxin. In trials, scientists attracted the ants to target areas by setting out cat food. The ants then swarmed the toads, killing half of them almost instantly. Of those who escaped, 88 percent died within a day due to their injuries. 

Read More: Stopping the Spread of Invasive Species

Exploring Cane Toad Cannibalism for Control

The ant idea didn’t become a widespread approach, and scientists have been experimenting with a new option that capitalizes on the toad’s cannibalistic tendencies.

In their tadpole stage, cane toads are cannibals. They sense a chemical released by other tadpole eggs and then gobble them up. Scientists worked to identify and replicate the chemical.

Conservationists are currently experimenting with a chemical bait that attracts the cane toad tadpole (but not its froggy counterparts) and then traps them so they can be humanely disposed of. Thus far, more than 1 million cane toad tadpoles have been removed from Australian waterways.

Read More: Why Cannibalism Is A Common Behavior For Some Animals

Using AI to Stop Invasive Hornets

Similar to how Australian species were defenseless to cane toad toxins, other species are helpless against invading wasps.

Wasps and bees have coevolved so that bees have defensive strategies against predatory hornets. But in the last few decades, species from Asia have made their way to Europe and the U.S., where the local bees are defenseless. 

In the U.S., the problem isn’t widespread, and officials have asked locals to alert them to the presence of Vespa mandarinia (also known as: giant northern hornet; murder hornets) But in Europe, the Vespa velutina, a close cousin of the murder hornet, is more widespread.

Scientists say they are past the point of relying on visual alerts from Europeans who spot a hornet or hive. They need earlier detection and think AI might be the answer. 

One possibility currently in development is called VespAI. This remote monitor has a bait station that can detect the presence of the murder hornet and distinguish it from other insects. The system then sends alerts so conservationists can manage the hornets’ nests.

Scientists are hopeful the early detection program can identify and eliminate the hornets before they have the chance to harm the defenseless bees.

Read More: The Negative Impact Goldfish Have on Freshwater Life

Article Sources

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Emilie Lucchesi has written for some of the country’s largest newspapers, including The New York Times, Chicago Tribune and Los Angeles Times. She holds a bachelor’s degree in journalism from the University of Missouri and an MA from DePaul University. She also holds a Ph.D. in communication from the University of Illinois-Chicago with an emphasis on media framing, message construction and stigma communication. Emilie has authored three nonfiction books. Her third, A Light in the Dark: Surviving More Than Ted Bundy, releases October 3, 2023, from Chicago Review Press and is co-authored with survivor Kathy Kleiner Rubin.