From the driest deserts to the lushest rainforests to frigid polar regions, ecosystems around the world each have a natural system of checks and balances. Within an ecosystem, plants and animals have evolved together over millennia, developing specific adaptations to thrive in their habitat and coexist with each other. Predators, prey and nutrient levels keep each other in check, ensuring that the natural functioning of an ecosystem stays relatively stable over time. However, history has proven that some species move, migrate, and get transported from their native habitat - a seed in a shoe, a fisherman releasing fish into a small pond, or larvae in an undrained boat bilges - and that's when trouble can begin.