Killing Predators on Islands is the Way Forward

Over at the Proceedings of the National Academy of Sciences, (PNAS), they note that invasive predators are implicated in a great deal of global biodiversity loss:

Invasive mammalian predators are arguably the most damaging group of alien animal species for global biodiversity. Thirty species of invasive predator are implicated in the extinction or endangerment of 738 vertebrate species—collectively contributing to 58% of all bird, mammal, and reptile extinctions. Cats, rodents, dogs, and pigs have the most pervasive impacts, and endemic island faunas are most vulnerable to invasive predators. That most impacted species are insular indicates that management of invasive predators on islands should be a global conservation priority. Understanding and mitigating the impact of invasive mammalian predators is essential for reducing the rate of global biodiversity loss.

I have noted the problem before. Back in 2004, I noted that rats have been responsible for more extinctions than anything else. Other predators such as feral cats, wild dogs, fox, and pigs have also hammered island endemics, as have feral goats.

The good news is that there is now a concerted campaign to kill off island predators, and it is resulting in a massive environmental turnaround where it is being done. Some examples:

• Seven islands in Baja Mexico were wiped clean of goats, rats, cats, rabbits, and burrows. Wildlife has roared back.


• On Ascension Island cats were eradicated and birds have roared back.


• On Saint Nicolas Island in California, cat eradication has resulted in the return of seals.


• On Cliperton Island, off of Mexico, feral pigs were shot out and the birds have returned.


• In the Galápagos Islands, feral goats have been wiped out and vegetation is growing back, and tortoises and birds are thriving as a result.


• In the Catalina islands, moving golden eagles and killing feral hogs has been a fabulous success for native Island Fox.