This study was conducted to provide insight into the response of Achyranthes japonica to management tools in the form of complete shoot removal (clipping) and herbicide application at Cypress Creek National Wildlife Refuge (CCNWR) in southern Illinois. Field herbicide experiments indicate that A. japonica is susceptible to foliar applications of systemic, broad leaf herbicides. The removal of A. japonica by herbicide, however, did not allow for re-establishment of the surrounding plant community in years 2011 and 2012. Seedlings at node stage 3, 4 and 6 were able to regrow following complete shoot removal indicating that this species can sustain perennial growth when it develops three nodes and that the node stage at which plants were clipped did not affect their regrowth potential. In the greenhouse, A. japonica was able to regrow following complete shoot removal at the 3 node stage and the number of branches and apical nodes on a plant are the best predictors of the regrowth potential for this species. Achyranthes japonica's susceptibility to foliar applications of systemic herbicides in the greenhouse was high. Herbicide titration results indicate that of the six herbicides tested (2,4-D ester, triclopyr, glyphosate, aminopyralid, triclopyr+fluroxypyr, and aminopyralid+metsulfuron) triclopyr required the least amount of active ingredient to reduce the growth of A. japonica by 50% (GR-50). Results overall suggest that A. japonica reaches perennial growth by the time it has three nodes, making clipping as a management tool only successful if done before plants have developed three nodes. Achyranthes japonica perennial plants are highly susceptible to foliar applications of broad leaf systemic herbicides making them a good management tool in the field.

AN ABSTRACT OF THE THESIS OFNicholas Seaton, for the Master of Science degree in Plant Biology, presented on December 4, 2019 at Southern Illinois University Carbondale. TITLE: THE EFFECT OF DEER BROWSE ON ACHYRANTHES JAPONICAMAJOR PROFESSOR: Dr. David GibsonPlants respond in many ways to damage. These responses vary between sites depending on the severity and duration of the incident. One common form of damage in the forest understory is herbivory or browse. White tailed deer (Odocoileus virginianus) have been observed to change the dominant species of forests by selectively browsing palatable species in the understory. These changes in species dominance can lead to unwanted consequences, sometimes resulting in a proliferation of weedy or invasive plants or a reduction in performance and competitive abilities based on morphological traits. Understanding the changes that occur to undesirable species after deer browse can help land managers in their prioritization of sites for land management and understand the driving forces behind a species’ success or failure. Using deer exclosure plots, this study looks at the effects of white-tailed deer on Achyranthes japonica, an herbaceous invasive species in the Ohio River floodplain of Illinois and surrounding states. White tailed deer have been observed to browse A. japonica throughout the invaders range, but little is known about the plant’s response. Deer browse data were collected in the summer of 2018 from May to August. Estimated deer densities among six study sites ranged from 8 to 22 deer per km2. Plants that were browsed during the growing season were morphologically different to those that were not browsed. Browsed plants were 11.5 ± 0.1 cm shorter (F1,218=11.658; p<0.001) on average and produced 0.33 ± 0.09 fewer nodes (F1,216= 4.045; p<0.05). Browsed plants also produced 2.7 ± 0.32 fewer flowering spikes and were similar in length to those of un-browsed plants. These morphological differences showed significant variation between sites. Floristic Quality Indices of the herbaceous plant communities (Ȳ =3.5) ranged from 3.2 to 3.9 among study sites. This study shows that site conditions can impact the response of A. japonica growth as it continues to invade across its current introduced range and that the species is adaptive and grows along-side other similar weedy species such as Microstegium vimineum and Parthenocissus quinquefolia. This study also indicated that deer browse has little to no impact on the growth of Achyranthes japonica.Keywords: Achyranthes japonica, Odocoileus virginianus, herbivory, browse, deer density, site quality