H2O18 as An Analyzer of Phragmites Australis Invasion Potential From Wet to Dry Sites.

The invasive wetland plant species Phragmites australis has become a major concern for land managers. The primary method of P. australis reproduction is vigorous expansion of an interconnected rhizome system.  Studies have shown that rhizomes are capable of translocating water over short distances but have not shown the extent to which this is possible.  Thus, it may be possible for P. australis to colonize upland sites and support satellite populations by translocating water through the rhizome system.   .

During our study, P. australis was grown in nine, 3.0 m long vinyl watering troughs containing vermiculite. The treatments were: a control (wetland conditions), an upland condition with satellite population connected to parent plant and an upland condition with a severed satellite population. All treatments were replicated three times. The parent plants were watered through the pulse-trace method, in which H₂O¹⁸ was used to trace water flow from the parent plant to the satellite community. Then, 5 cm shoot clippings from the shoot/rhizome interface were collected every 30 centimeters and water was removed through vacuum extraction. Samples were tested via isotope ratio mass spectrophotometer to determine concentration of H₂O¹⁸ within each sample.  Sample analysis indicates translocation of water from parent plant to satellite community along with survival of the satellite community.