Student/presenter: Justin Dawsey, undergraduate, Natural Resources Management
Format: Poster presentation
Title: Competitive Ability in Silverleaf Nightshade, an Invasive Weed
Justin Dawsey1 and Cade Coldren2
Texas Tech University, 1Department of Natural Resources Management and 2Department of Plant and Soil Science
Silverleaf Nightshade (Solanum elaeagnifolium) (SLN) is a noxious, invasive weed that is responsible for lowering crop yields and invading disturbed sites across North America, Australia, and several other regions around the world. The objective of our study was to examine how SLN competes with other species at the Quaker Farm on the Texas Tech University campus. Plots were set up around individual SLN plants and plant height, cover, and distance and bearing were recorded for each individual plant, several times during the growing season. We found that increased rainfall and average temperature were drivers in the time of SLN emergence. Shortly after emergence, no pattern existed between density of non-SLN plants and their distance from each SLN plant. However, after one month of growth, few non-SLN plants were found close to SLN plants, and their density increased with distance away from SLN plants, reaching a peak at about 12 cm. This pattern held through the end of the growing season. Regarding cumulative rainfall, mean height by species tended to increase with increasing rainfall, but this was significant for only one species (Convolvulus arvensis), implying that water availability for growth was limited. Given these results, we suspect SLN is competitive via several non-mutually exclusive strategies: allelopathy, reliance on use of previous disturbance, and an inefficient but flexible use of water. More research will be needed to understand the role each may play in SLN invasion.