An Invasive Plant Watch List for the National Capital Regional National Parks (USA)

Abstract

Early detection and rapid response (EDRR) are critical tools for managing invasive plants. A watch list made up of high-priority early detection species that are not yet known to occur in the target area is an important EDRR tool. To make a watch list I used the EDDMapS database of plant occurrences to identify nonnative plants reported within 150 miles of the District of Columbia. I sorted the list to include only species not reported by park staff to be invasive in park natural areas. The resulting 97 candidate species were prioritized using NatureServe's Invasive Species Assessment Protocol (ISAP) to produce an Invasive Species Impact Rank (I-Rank). The ISAP includes questions in four categories (Ecological Impact, Current Distribution and Abundance, Trend in Distribution and Abundance, and Management Difficulty). Each category contributes to an overall I-Rank. The 20 species with the highest I-Rank became the basis for a priority watch list. The watch list will be used to guide presence/absence data collection and treat all identified populations on park land. Removing these populations will protect natural areas and reduce management costs in future years.