Conservationists divided on Florida’s decision to kill off invasive iguanas

By Erica Cirino

Florida is struggling with a fast-increasing population of invasive green iguanas that began as a small group of released and escaped pets. Thriving in the warm sunshine and humid climate, experts believe hundreds of thousands of nonnative iguanas now call the Sunshine State “home.”

Green iguana in Florida. Photo: Slegrand (Wikimedia Commons)

There, state conservation officials claim they threaten the wellbeing of native animals, including the rare Miami blue butterfly: The green iguana likes to munch on the leaves of the Nickerbean blue plant, the same plant on which the endangered butterfly lays its eggs. Officials also say iguanas are responsible for damage to sewer lines, roads, homes and gardens; and pose a disease risk to humans and other animals.


To reduce the green iguana population, the state has taken what a group of scholars and scientists is calling an “inhumane” approach to the issue: A 15-person team from the University of Florida is currently storming across the state, killing wild green iguanas by zapping them with electric cattle guns and smashing their heads against their trucks, boats and other hard objects. The $63,000-project, an attempt to reduce the population of invasive reptiles across the state, is contracted by the Florida Fish and Wildlife Conservation Commission. Opponents to the killing project have sent a letter to the commission urging it consider nonlethal control methods, such as birth control, or at the very least, to investigate more humane methods of killing the invasive species.

“It is important to stress that, as scientists ourselves, we are committed to the health of our ecosystems and we know that this conversation is an important one. Our central point, however, is this: There is no extreme urgency faced in Broward County in 2018 by the behavior of these iguanas and no reasonable justification for the extreme actions being taken,” they wrote. The letter is signed by 20 individuals, including prominent animal behavior and neuroscience experts including Marc Bekoff of the University of Colorado, Denver; and Safina Center Creative Affiliate Lori Marino, formerly of Emory University and currently executive director of the Kimmela Center for Animal Advocacy, Inc., and the Whale Sanctuary Project.

Both the letter-writing group and the Humane Society of South Florida contend that no iguanas should be killed, and instead, efforts toward coexisting with the invasive species should be made.

While some take a hard stance against any method of killing invasive species for population control, the extinction of native species might be a more frightening prospect. Take for example the case of invasive rats being introduced to the Hawaiian island of Lehua after hitching rides on ships from other parts of the world. After rats began harming the population of native Laysan albatross and many other species on the island (including native vegetation), wildlife managers dropped poison to kill the rats without harming any other species. As of November 2017, the island has been rat-free and native birds “are flourishing with no further sign of rat attacks on eggs, chicks or adults on nests. Plant leaves and new shoots that were previously consumed by rats are persisting. Many of the plants are in bloom,” according to the Hawaii Department of Land and Natural Resources.

Lehua island, Hawaii. Photo: Christopher P. Becker, Polihale: (Wikimedia Commons)

“Humans brought those invasives, so humans must address the consequences,” said Safina Center Fellow Hob Osterlund, founder of Kauai Albatross Network, a nonprofit organization working to reduce threats to the survival of albatross and other birds on the Hawaiian islands. “If we do nothing, we are inadvertently condoning the extinction of countless natives. On Lehua Islet in Hawaii last year—before the rat extirpation began—only two albatross chicks fledged.  This year, after the pellet distribution, there were close to one hundred and forty albatross nests. The results tell us what we need to know.”

Like rats, green iguanas, which are native to Central and South America, found refuge in a new land thanks to people. The letter signed by Bekoff and Marino emphasizes the fact that the state’s iguana problem is a result of human carelessness. The letter states that, while they are deemed invasive and possibly harm the native environment, green iguanas “deserve compassionate treatment by scientists just as individuals of non-invasive species do.” Its authors also strongly suggest Florida implement stricter rules about ownership of exotic animals, including iguanas, as pets.

Green iguana in Florida. Photo: Korall (Wikimedia Commons)

“While we overlook our responsibility to the environment with lenient regulations on exotic animal pet trade and the [commodification] of other species, we ask the iguanas to ‘take the fall for us,’” Marino said in a message to one of the letter’s co-signatories, Barbara King, emerita professor of Anthropology at the College of William and Mary. “There is nothing humane or even scientifically-sound about ‘fixing the landscape’ to our liking. But that is exactly what is being done by the University of Florida in the [wanton] killing of healthy iguanas.”

Originally posted 2018-04-19 23:51:15.

To native birds’ benefit, conservationists declare South Georgia clear of invasive rodents for first time in more than 200 years

South Georgia. Photo: Carl Safina

Celebrated sea captain James Cook implanted a British flag down into the rocky, icy ground on the shore of South Georgia in 1775. When he did so, he claimed ownership of the icy, mountainous Antarctic island not only for his country’s humans, but, inadvertently, also for its rodents. From the arrival of Cook onward, ships carrying explorers, scientists, whalers, fishers and seal hunters continued to fuel the island’s exploding population of rats and mice. The rodents quickly adapted to the cold and icy conditions of their unforgiving new home—subsisting off local animals, particularly seabird chicks, which—like most remote island animals—never evolved defenses against such ruthless predation.

Wild rat. Photo: Reg Mckenna/Wikimedia commons

After more than 200 years after they first colonized South Georgia, by the early 2000s, rats and mice had munched many native species to the very edge of existence, including the South Georgia pipit, a tiny songbird, and South Georgia pintail, a duck—two birds found nowhere else in the world. But after seven years of eradication work, launched in 2011, conservation group South Georgia Heritage Trust has just announced it has completely rid the island of rodents. This, the Trust says, will provide a safer future for South Georgia’s native wildlife—especially its vulnerable native birds. South Georgia is home to the largest and second-largest king penguin colonies in the world, as well as countless other bird species, including albatross, shearwaters, petrels, cormorants, skuas and more.

Gray-headed albatross in ground nest in South Georgia. Photo: Patricia Paladines

“Thanks to the outstanding work of the passionate and committed members of Team Rat and the Board of Trustees, the birds of South Georgia are free from the threat of rodents,” said Mike Richardson, chairman of the South Georgia Heritage Trust said in his announcement. “The Trust can now turn its attention and efforts to working with the Government of South Georgia & the South Sandwich Islands on conservation of a different kind: the conservation and reinterpretation of the island’s historic cultural heritage to educate and enlighten future generations about our environment.”

South Georgia Heritage Trust rolled out its rodent eradication work over four phases, from 2011 to present. For three field seasons, “Team Rat”—a group of pilots, engineers, chefs, doctors and field staff—was deployed to South Georgia. The field team prepared hundreds of tons of poisoned bait that was dropped from several helicopters cruising over the island. The hope was that the rodents would take the bait and then retreat to their underground burrows to die, out of reach of scavenging animals, like gulls, that could potentially be poisoned by eating dead rats and mice.

In 2017, two years after it dropped its final round of poison, South Georgia Heritage Trust rolled out the final phase of its project: checking the island for signs of rodents. Field staff placed thousands of wooden stakes into the ground, and tied to them wax tags and plastic cards dipped in vegetable oil or peanut butter—attractive snacks for gnawing rats—to check for signs of rodents. Two canine handlers lead three rodent-detection dogs across South Georgia. By the end of 2017, the devices and dogs exposed no signs of rats.

King Hakkon Bay, South Georgia. Photo: Carl Safina

The presence of invasive rodents on remote islands is extremely dangerous to native species. I have seen the incredible devastation rats can cause to seabird colonies on islands in the Atlantic, on Midway Atoll, in New Zealand’s sub-Antarctic, and in South Georgia.

In South Georgia, with black-browed albatross. Photo: Patricia Paladines

But I have also witnessed the benefits of eradication, the more-incredible resurgence of birds and vegetation when rats are vanquished from the same oceanic islands, including the outer islands of South Georgia; those smaller islands had already been made rat-free by the last time I visited a little over a year ago. Rats have probably driven more island-bird extinctions than any other human-introduced species. South Georgia’s pipit has now been saved from likely extinction and there will probably be hundreds of thousands, perhaps millions, more seabirds nesting there in coming years.

Black-browed albatrosses in South Georgia. Photo: Carl Safina

Ecologist Carl Safina is author of seven books, including the best-selling “Beyond Words; What Animals Think and Feel,” and “Song for the Blue Ocean,” which was a New York Times Notable Book of the Year. His writing has won a MacArthur “genius” prize; Pew and Guggenheim Fellowships; book awards from Lannan, Orion, and the National Academies; and the John Burroughs, James Beard, and George Rabb medals. His work has been featured in The New York Times, The Los Angeles Times, The Washington Post, National Geographic, and elsewhere, and he hosted the 10-part “Saving the Ocean” on PBS. Safina is founding president of The Safina Center at Stony Brook University.

Originally posted 2018-05-12 01:55:49.


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