A study on waterlogging as a potential tool to control Ligustrum sinense populations in western Tennessee

Abstract

Ligustrum sinense (Chinese privet) is an introduced species in the United States. Dense stands of L. sinense are found in the understory in many bottomland forests in western Tennessee. The widespread abundance of this species is problematic because of the potential loss of valuable native bottomland species due to competition. Flooding has been proposed as a potential means of eradicating this species. Therefore, the objectives of this experiment were to examine survival, growth, and physiological responses of L. sinense under various flooding and shading regimes. An experiment consisting of three levels of flooding (control, shallow flooding, and deep flooding) and three levels of shading (full sun, 30–35% full sun (photosynthetic active radiation), and 10–15% sun) was performed in a greenhouse. Plant gas exchange was adversely affected in all flooded plants. Likewise, growth (height and diameter) was lower in those plants that were flooded as compared to non-flooded plants. However, morphological adaptations (i.e., lenticels and adventitious roots) were observed by the third week of the experiment. Plant survival in flooded treatments was 75% by the conclusion of the experiment, with an equal rate of survival seen in the shaded treatments compared to non-shaded. Although flooding alone did have significant effects on physiological function and growth, shading and shading × flooding interaction were not significant. Our data support the hypothesis that L. sinense is capable of withstanding both short-term flooding and shading; thus, short-term flooding is unlikely to irradicate this species from the infested bottomland stands.