Regional mapping of plant invasion based on expert opinion

Three of the most pervasive nonnative invasive species in the Southeast United States are kudzu (Pueraria montana), cogongrass (Imperata cylindrica), and Chinese privet (Ligustrum sinense). Their combined impact on the region results in hundreds of millions of dollars in economic losses and ecological damage, in addition to the high costs associated with controlling these aggressive invasive plants. Despite their importance, the distributions of these plant invasions are poorly known. Presence locations are available in a few localized databases, but regional data have not been collected or synthesized. Here, we use information collected from local experts to develop a comprehensive, high resolution map of these three species across 11 southeastern states. We map species presence using ¼ USGS quadrangles, which are at approximately 6 km resolution. Data were collected from local experts through an electronic survey campaign. The resulting distribution map is an appropriate tool for weed managers to determine hot spots of invasion and coordinate large-scale management across the Southeast United States. Additionally, the map is useful for gauging ecological and economic risk presented by these invasive species.