Plants, animals, insects and fish are moving in. Invasive species threaten local ecosystems and the planet's biodiversity, but are they all as bad as we think they are? In Nature Out of Balance:How Invasive Species Are Changing the Planet author Merrie-Ellen Wilcox profiles all-star invasive species around the world, starting in her own neighbourhood, and warns that humans are the most invasive species of all. We find out how and why species become invasive, what we can do to stop their spread and whether it's time to think differently about invasive species that are here to stay.