Columbia River CASI Imagery as part of our Biocontrol Project

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).

Lythrum salicaria occurs throughout the CR estuary
We have shown that Lythrum salicaria has the potential to affect both the structure and function of important tidal wetlands
Consequently, there is an interest in controlling Lythrum.
Several groups have released biocontrol agents at multiple sites in the CR estuary.

Release Sites

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).

Quadrats arranged along four transects at a release site. Circles represent buffered distances from release site to evaluate spread of biocontrol agents.

We are now beginning to look at environmental factors that may favor biocontrol agent populations at some site and not others.

Chris helping out with a transect, hiding in the jungle.

Table 1. Project elements by year.

Element

I a: Estimate plant damage

b: Estimate presence/absence and population levels of biocontrol agents using adults, larvae and eggs

II a: Elevation

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

2006

X

2007

X

2008

X