ScienceNews: As climate changes, some environments are becoming hostile to the flora and fauna that long nurtured them. Species that can migrate have begun to move into regions where temperatures and humidity are more hospitable. And that can prove a conundrum for officials charged with halting the invasion of non-native species, notes Jon Jarvis, a biologist who for the past year has headed the National Park Service. One problem: What’s native? Species move at will as conditions change. What’s …