During surveys in 2009, we documented seven invasive exotic plant taxa in the Big Spring Pines Natural Area, Chubb Hollow, Long Bay Field and Long Bay at Ozark National Scenic Riverways. All species were known to occur on the park. The most widespread and abundant of the exotic plant species observed included Johnsongrass, ground ivy and Nepalase browntop. Each of these species covered seven or more acres in the park. In general, several invasive exotic plants are a major problem in the study area at Ozark National Scenic Riverways, but successful control is possible for a large group of species. The acreage estimates presented in the report may be used to plan management activities leading to control of exotic plants and the accomplishment of GPRA goal IA1b.

A review of NPS species, the national database registering plant occurrence in parks, indicated that 465 plant species occurred in Hopewell Culture National Historical Park. Of these, 148 (32%) are non-native, meaning that these plants were recently introduced through human agency. The authors detail the status of invasive plants and the resource management issue(s) for the park.

The authors conducted a second year of invasive plant surveys at Lincoln Boyhood National Memorial. This allowed a comparison of invasive plant species found in 2006 to those found in 2011. their findings are detailed in this publication.