Grasses are one of the most abundant floras on all continents except Antarctica. Their divergence is estimated to have taken place 200 million years ago. Humans have intentionally and unintentionally introduced these species to North America through travel and trade. On the North American plains, prairies, grasslands, and meadows at least 11% of grasses are non-native. North America is considered a hotspot for many invasive plant species of grasses, which threatens all of the endangered native grass species and potentially threatens other grass species. Conservation tactics and management policies can help prevent invasive species from taking over and driving native North American plants to extinction.