Description:
Intermountain Aquatics (IMA) worked with the Nature Conservancy in 2005 to address two key challenges that emerged during earlier phases of stream restoration efforts. First, plantings on expanded streambank areas created by placement of coir rolls (“Biologs”) on Stalker Creek were largely unsuccessful due to death of most planted plugs. Second, observations on Stalker Creek and other area streams suggest that reed canarygrass (Phalaris arundinacea), an aggressive rhizomatous grass, is a threat to long-term success of stream restoration projects in the area. Both problems were related to the distinctive hydrology of area streams, which reflected a predominant groundwater source and the influence of dense aquatic vegetation on stream levels during the growing season. Approximately 6000 ft2 of wetland sod was planted in 2005 on five separate “point bar” areas of Biologs and fill. Survival and growth of both sedge and bulrush sod were excellent. At the end of the growing season aerial cover of plants averaged 75% and 55%, respectively, in sedge and bulrush areas (sedge growth is naturally denser than bulrush). Glyphosate control of reed canarygrass was tested in six areas totaling 17,440 ft2 along Stalker Creek. The six areas represented a range of hydrologic conditions and moderate to extreme infestations of reed canarygrass. Test plots were mowed in late May and sprayed after re-growth in late June and again in late August. Three revegetation methods were tested in 2006: medium density plugs (individual plants) without hydromulch, high-density plugs with hydromulch, and wetland sod. An unplanted “passive revegetation” control was also evaluated. Results from the 2006 test plots will be summarized in 2007.