Tue, Aug 03, 2021:On Demand
Background/Question/Methods
The purpose of this investigation was to determine the effect of soil moisture on the growth of Lythrum spp: purple loosestrife (Lythrum salicaria) and winged loosestrife (Lythrum alatum). Wetlands provide essential ecosystem services such as water purification and flood control. Purple loosestrife, an herbaceous perennial, native to Europe and Asia, has become invasive in North America, spreading in wetlands throughout the eastern United States and Canada and becoming a serious threat to the biodiversity of wetlands. It forms dense stands, crowding out native plants, resulting in loss of habitat for native plant and animal species and changes in nutrient flows within the wetland ecosystem. Winged loosestrife, a congener native to North America, is a non-aggressive member of wetland communities in eastern North America. Seeds for purple loosestrife from Sussex County NJ, USA, and the United Kingdom, and winged loosestrife from the Midwest region of the USA were grown under greenhouse conditions and supplied different amounts of water during the growing season. The height of each plant was measured weekly and, three times during the growing season, some plants were harvested, dried, and weighed.
Results/Conclusions Purple loosestrife plants from Sussex County seeds had lower height and mass at the least amount of water supplied but grew more with the medium and higher water levels. Purple loosestrife plants grown from seeds from the UK had greater height in the medium and wet conditions than in the dry condition. Winged loosestrife plants from Midwest USA seeds showed lower growth in height and mass in the dry and medium conditions than in the wet condition. These results indicate that purple loosestrife is able to grow well with less water than winged loosestrife, while still growing well in the wet conditions in which winged loosestrife grew best. Both purple loosestrife and winged loosestrife would be able to grow in areas close to a water source, while purple loosestrife would also be able to grow further upland away from the water source. The ability to grow well in a wider range of conditions would allow purple loosestrife to cover greater areas within the wetland and may contribute to its invasiveness.
Results/Conclusions Purple loosestrife plants from Sussex County seeds had lower height and mass at the least amount of water supplied but grew more with the medium and higher water levels. Purple loosestrife plants grown from seeds from the UK had greater height in the medium and wet conditions than in the dry condition. Winged loosestrife plants from Midwest USA seeds showed lower growth in height and mass in the dry and medium conditions than in the wet condition. These results indicate that purple loosestrife is able to grow well with less water than winged loosestrife, while still growing well in the wet conditions in which winged loosestrife grew best. Both purple loosestrife and winged loosestrife would be able to grow in areas close to a water source, while purple loosestrife would also be able to grow further upland away from the water source. The ability to grow well in a wider range of conditions would allow purple loosestrife to cover greater areas within the wetland and may contribute to its invasiveness.