Going, going . . .
Creatures that live in North America’s streams, lakes and rivers are in just as much danger of extinction as the denizens of tropical rainforests, says Anthony Ricciardi of Laval University in Quebec. He has devised a computer model that predicts the extinctions likely to be caused by pollution, dam construction, dredging and the introduction of exotic species (Conservation Biology, vol 13, p 1220). The model predicts that fish, crayfish,