Die-back and re-growth of Phragmites australis (common reed) following drought

Background/Question/Methods

Common reed (Phragmites australis) is one of the most widely distributed flowering plants. The native and introduced lineages occur in wetland and riparian areas covering a range of climate types. In the Central Great Plains, significant alterations have occurred in hydraulic regimes through the erecting of dams, bridges, and irrigation diversion structures. The changes in stream flow and subsurface moisture content due to scheduled releases and periodic pulse flows of water have allowed for the creation of new plant assemblages. While the conditions of low water flow and availability can deter the establishment of native riparian plant species, introduced common reed is thought to be able to survive and even spread due to extensive underground rhizomes, stomatal pore distribution on leaves, and high leaf area index. Therefore, a greenhouse study was conducted at the University of Nebraska in North Platte to determine the response of introduced common reed to induced drought conditions. Using large macrocosms, drought stress was imposed by maintaining low (-0.092 MPa), medium (-1.5 MPa), and high (>-1.5 MPa) soil water potentials for up to 41 days.

Results/Conclusions

Following the removal of drought stress treatments, medium stressed plants had the highest re-growth (628 g m^-2) compared to the low (278 g m^-2) and high (273 g m^-2) stressed plants. The recovery of introduced common reed following extended periods of drought could create additional management challenges in riparian and wetland areas that may experience dramatic hydrological changes under future climate scenarios.