Out on a mountainside in Hawaii are a bunch of snails we’re concerned about. Some we’re concerned about because their numbers have dwindled far too low to be sure they are buffered against extinction. Others are invasive species, such as the African giant land snails that compete with the Oahu snails, and predatory snails like the rosy wolf snail that eat the native snails. How to address the invasive snails–and many other invasive species, from plants to rats–is a huge, unanswered challenge that you can read about here .