Assessment of Biocontrol Agents in the Lower Columbia River Estuary: 2006-2008
The Goal of this project, funded by the Army Corps of Engineers, is to assess Biocontrol Agent populations at 15 release sites made in 2005 in the Columbia River Estuary (RM 18-52).
Results will be used to determine where future biocontrol agents releases will be made and will help to identify environmental factors that lead to successful establishment and control of the invading plant.
We have found adult Galerucella at 13 of the 15 USACE release sites during 2006 and 2007. This strongly suggests that these biocontrol agent populations are becoming established (organisms need to be recovered for three years before populations are considered to be established).
Table 1. Project elements by year.
|I||a: Estimate plant damage|
|b: Estimate presence/absence and population levels of biocontrol agents using adults, larvae and eggs|
|b: Distance to shrub/forest and high ground|
|c: Tidal stage/water depth|
|III||Helicopter surveys of 35 transects/remote sensing|
|IV||Model optimal release sites|
|V||Tolerance of Galerucella pusilla to submersion|
We are now beginning to look at environmental factors that may favor biocontrol agent populations at some site and not others.
Table 2. Galerucella spp. found.
|Eureka Bar Downstream|
|Eureka Bar Upstream|
|Miller Sands Downstream|
|Miller Sands Upstream|