India, April 26 -- As they quietly expand their kingdoms, we can look in the mirror and ruefully shake our heads. Over the past two centuries, amid growing trade and amid colonisation, plants, trees, fish and mammals have been transported from their home territories to new regions, for a range of reasons. Some shrubs were pretty, so they were planted as hedges (see the story alongside, on the lantana, for a bit on how much damage this has done). Some trees grew fast and seemed intriguing; now, it turns out there are few ways to stop them. Fish, ants and other insects were moved along sea routes, both intentionally and unintentionally, and now suck oxygen and nutrients out of distant water bodies. Invasive alien species crowd out natives, al...