We often hear that alien species are wiping out many native plants and animals. But the evidence is both scanty and overused

(Image: Andrzej Krauze)

SOME “facts” are just too good to check. You might hope science would be immune from this sort of pitfall, but it seems not.

In much of ecology, it is taken as read that invasive species were a major culprit in recent extinctions. This is widely stated, despite a lack of evidence for it. While doing research for my latest book, I found the claim being passed on in ways reminiscent of Chinese whispers.

The UK government’s Non-native Species Secretariat (NNSS) declares that invasive species have “contributed to 40 per cent of the animal extinctions that have …