Nature in Australia is a mess. There’s no need to go into details. You’ve seen it: the thousands of dead fish in drying rivers, three billion animals killed or displaced by bushfire, environmental legislation that privileges developers over endangered species. Up against all this are conservationists—scientists and activists slogging away in a losing battle to explain the size of the problem, to get laws changed, to stop a tree being felled or a mine being opened, to pluck species from the brink of destruction with monitoring and intervention.

For most of Australia’s conservation history, those fighting on the side of nature—from ecologists to birdwatchers to tree-sitters and warm-hearted animal lovers—have cleaved to the belief that native species are good and introduced species are bad, that getting rid of introduced species will go a long way to solving nature’s worst problems. As a child of environmentalists, I was fed this belief with my Vegemite on toast. But as natural systems begin to collapse, this belief is collapsing along with them.