Proceedings of the Third International Conference on Invasive ...

<strong>Proceedings</strong> <strong>of</strong> <strong>the</strong> <strong>Third</strong> <strong>International</strong> <strong>Conference</strong> on Invasive SpartinaChapter 4: Spartina Control and Managementpotting medium and each pot placed into a wet bed (1.83 mx 2.44 m wood-framed beds lined with three layers <strong>of</strong> 6 mmclear plastic) containing ei<strong>the</strong>r 0 ppt, 15 ppt or 35 ppt salinewater to a depth <strong>of</strong> 10 cm. A total <strong>of</strong> six wet beds werecreated (two at each salinity level) with three utilized for <strong>the</strong>San Francisco fragments and three for <strong>the</strong> Willapa Bayfragments. Salinity <strong>of</strong> <strong>the</strong> wet beds was monitored every oneto three days and adjusted with saline or fresh water asneeded.A total <strong>of</strong> 234 fragments, all having at least one culm,were potted from <strong>the</strong> San Francisco samples. A total <strong>of</strong> 353fragments having at least one culm were potted from <strong>the</strong>Willapa Bay samples. An additional 116 fragments with noculms attached were created from <strong>the</strong>se samples. Thepurpose <strong>of</strong> <strong>the</strong>se fragments was to test if survival wasdependent upon <strong>the</strong> presence <strong>of</strong> at least one culm assuggested by Randall and Milne (unpublished). Small andlarge rhizome fragments were immersed in <strong>the</strong> saline baths(0 ppt, 15 ppt or 35 ppt) for ei<strong>the</strong>r 4 or 16 days. Theimmersion duration treatments for <strong>the</strong>se culmless fragmentsTable 1: S. alterniflora rhizome fragment metrics following single-pass,winter rototilling effects in Willapa Bay.MeasureMean ± SDNumber <strong>of</strong> fragments per 0.25 m 2 x 0.1m deep 77.7 ± 13.7Percentage with ≥ 1 culm 87.8 ± 3.86Rhizome length (cm) 4.96 ± 3.38Rhizome diameter (cm) 0.58 ± 0.29Culm length (cm) 5.37 ± 3.58Culms per fragment 1.31 ± 0.89were extended by 1 day to allow adequate time for planting<strong>of</strong> <strong>the</strong> culm treatment groups. They were <strong>the</strong>n individuallypotted in <strong>the</strong> same sterile potting medium and placed in <strong>the</strong>wet beds.Pots were randomly positioned within <strong>the</strong> wet beds. All6.50.8Rhizome Length (cm)6.05.55.04.5Rhizome diameter (cm)0.70.60.54.00.412Quadrat312Quadrat381.6Culm Length (cm)765# <strong>of</strong> culms1.51.41.31.241.112Quadrat31.012Quadrat3Fig. 1: Interval plots by quadrat (with 95% C.I.) <strong>of</strong> rhizome length, rhizome diameter, culm length and number <strong>of</strong> culms per rhizome fragment foundimmediately following single pass, winter rototilling in Willapa Bay, WA.- 257 -