Point Mapping Integrates Data Collection and Weed Control Operations

In this case study, we evaluated a point-mapping method for simultaneously collecting data while controlling three invasive woody plant species: black locust, Chinese privet, and hardy orange. The study in Arkansas Post National Memorial included seven project areas ranging in size from 2.7 to 27.3 ha and spanned six field seasons (2010 to 2015). The control techniques varied depending on plant size and always included the application of herbicide, which also varied over the course of the study to include glyphosate, imazapyr, and triclopyr. Each person responsible for controlling plants simultaneously collected global positioning system point data to estimate the foliar cover of the plants treated. The resulting data demonstrated evidence of decreases in all three plant species in most project areas during the 6-yr period. Initial increases in area treated for some species—area combinations reflected differences in the preliminary efforts required to control invasive plants in entire project areas, but by 2012 six of seven project areas were treated in their entirety. Despite a high level of reduction, in some cases, the plants persisted at low levels even during the sixth year of the project. Our findings support the ability of this method to granularly detect changes in plant abundance while simultaneously controlling invasive plants. With several acknowledged limitations, this streamlined project-based monitoring approach provides data that allow managers to assess the effectiveness of weed control treatments. Nomenclature: Glyphosate; imazapyr; triclopyr; black locust, Robinia pseudoacacia L.; Chinese privet, Ligustrumsinense Lour.; hardy orange, Poncirus trifoliata (L.) Raf.