Conserving the rarest species on the planet can be a complex problem, and a silver bullet solution has so far been evasive. However, like the silver bullet which killed mythical creatures, mammal eradications appear to solve this problem and indeed save species. This week two open access papers have independently been published, both demonstrating the supremacy of invasive mammal eradications for saving species. A large international consortium of scientists (of which I was one) today published in Proceedings of National Academy of Sciences a global review which shows not only the large number of mammal eradications on islands which have taken place but also the large number of species which have benefited. The study found 596 populations of 236 native species on 181 islands benefited from these eradications. Four species on the IUCN red-list were in part saved by mammal eradications from their islands.
Our regionally focused paper on the distribution of introduced mammals on the 2,000 islands of the Western Indian Ocean was also published in the open access journal Global Ecology and Conservation. These islands are a particularly forgotten part of the world, with a great story and history to tell. Although there have been far fewer eradications in this region, only 45, the results support the global study. Predator eradication, along with control and habitat management, has contributed to the recovery of at least 24 threatened species, and 8 species down-listed on the IUCN red-list. Greater investment and prioritisation in island conservation in the region is warranted.
Such clear-cut evidence for the value of invasive mammal eradications has previously been lacking, with only a few local examples of benefits in the literature. With larger reviews such as these now available, it is becoming increasingly difficult to oppose invasive mammal eradications to save species – literally from extinction. In another paper with the same group of authors we make a clear ethical case for invasive mammal eradications on islands. Why should the suffering and rights of species being eaten to extinction by invasive mammals be ignored, after we introduced those very same mammals to the islands?