Invasive exotic plants pose a serious threat to the natural resources of many national parks. Invasive species can displace native plant species, inhibit the regeneration of native forest trees, degrade habitats for rare species, and alter vegetation community structure and composition. Due to these potentially serious impacts; the status, trends, and early detection of invasive species is currently considered a Tier 1 vital sign for terrestrial ecosystems in the Eastern Rivers and Mountains Inventory and Monitoring Network.