Invasive species are costing the world at least $423bn every year and have become a leading threat to the diversity of life on Earth, according to a UN assessment.

From invasive mice that eat seabird chicks in their nests to non-native grasses that helped fuel and intensify last month’s deadly fires in Hawaii, at least 3,500 harmful invasive species have been recorded globally in every region, spread by human travel and trade. Their impact is destructive for humans and wildlife, sometimes causing extinctions and permanently damaging the healthy functioning of an ecosystem.