Thanks to Ted Williams at Cool Green Science for this article about the eviction of an invasive species in a remote location with charismatic species both native and introduced:
Early in the 20th century settlers on the islands of Chañaral and Choros off northern Chile had a brainstorm: They’d create a ready supply of fresh meat by unleashing European rabbits.
It worked out as well as rabbit introduction in Australia.
In short order the aliens stripped away a rich array of native plants (many imperiled), reducing the islands to eroding dirt and rubble. They took over the nesting burrows of Humboldt penguins and Peruvian diving-petrels, now listed by the International Union for Conservation of Nature as vulnerable and endangered respectively. And they knocked down populations of the Atacama tree iguana, many-spotted tree iguana, braided tree iguana, Chilean slender snake, a spider found only on Chañaral and countless insect species including a beetle found only on Choros.
About half a century later settlers had another brainstorm: To cure Chañaral’s biblical plague of rabbits they’d introduce foxes. But the rabbits found sanctuary underground; and the foxes dined on petrels instead, wiping out a nesting population that had once numbered around 200,000. This deprived native burrowing owls of their most important natural diet. It also eliminated the foxes.
Finally, in 2013, people who knew what they were doing worked out a real solution. Island Conservation, a nonprofit team of biologists dedicated to preventing extinctions around the globe, partnered with the Chilean National Forestry Corporation. And, with support from Wisconsin-based pesticide manufacturer Bell Laboratories, Inc. and other U.S.-based funders, they eradicated rabbits on Choros in one year. Chañaral, bigger and with more complex terrain, was certified rabbit free late in 2017.
As on so many other islands success was made possible by the anticoagulant poison brodifacoum, sufficiently fast acting to kill rodents and rabbits before they learn to avoid it. The bait formulation, developed and produced by Bell Labs largely at its own expense, was the same one used in the recent salvation of Desecheo National Wildlife Refuge off Puerto Rico. This time, though, crews were able to deliver bait by hand instead of helicopter because rabbits move around more than rodents.
All it takes is one part brodifacoum per 40,000 parts bait. But fear and loathing of all poisons in all situations is a global phobia. Always the objections are these, and I’m quoting directly from hard copy and online commentary: “Poison is cruel.” “There has to be a better way.” “The nonnatives didn’t ask to be put there.” “Nontarget wildlife will die.” “Who are humans to call other species invasive?” “Don’t play God by killing one species in favor another.”
“Cruelty” by poisoning aliens doesn’t approach cruelty to natives by not poisoning aliens. There is no “better way,” in fact, no other way. “God” was played by people who made the mistakes of alien introductions, not by people correcting those mistakes. No recovery project ever “killed a species,” only individuals of abundant species in order to prevent extinction of entire species.
Constant practice has rendered Island Conservation adept at outreach. One advantage it had on Choros and Chañaral was that in 1990 Chile had designated these islands — along with a third, Damas — as the Humboldt Penguin National Reserve. Settlers left, and the islands became important for ecotourism, mostly for the rich marine life surrounding them. Today the 2,123-acre reserve sustains 80 percent of the planet’s remaining Humboldt penguins…
Read the whole article here.