. . . "Juvenile works" . "Discusses the tundra ecosystem and the role of lemmings as a keystone species in helping to maintain it, describing the lemmings' place on the food chain and what would happen to the tundra if they were to become extinct." . . . . . "What if there were no lemmings?" . . . . . "What if there were no lemmings? : a book about the tundra ecosystem" . .