Invasive exotic plants have become a major threat to ecosystem health in protected areas worldwide. Invasive plants are species that can multiply so successfully that they blanket an area and crowd out more desirable native plants. Exotic plants are those that have been introduced, both accidentally and intentionally, into areas outside of their native range. The changes caused by invasive exotic plants to the vegetation of an area can affect species richness and abundance by removing food sources, shelter and nest sites for wildlife, bird and insects. Exotic plants can also alter water availability and soil chemistry and can cause major economic losses. The detection, control and/or eradication of invasive exotic plants have become a key focus of the National Park Service and other federal agencies.