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Keep an Eye on Those Beetles! Monitoring Methods.

July 18, 2011

It is an integral part of every Galerucella release to monitor, at least annually, the impacts your project is having on the loosestrife populations. Monitoring can involve a simple visual observation, or a more rigorous, plot-based setup to determine the impacts of your released Galerucella beetles.

Regardless of the scientific rigor you apply to your monitoring efforts, mapping your locations using a GPS is the easiest way to share the information with regulatory agencies and other collaborators with the project, but hand-mapped locations on a topographic map can be just as informative and useful.

For a simple monitoring protocol, returning to your release sites in the fall and spring of each year and determining an approximate percentage of control can be done, along with looking for evidence of increase in the beetle population and activity. Photo points are also simple to set up, when loosestrife is in full bloom. Find a location in a release site that is easy to return to every year; you can mark it yourself or use an existing landmark. Photograph that site annually, in fall and spring, to track visually the damage your beetles have done.

For a more rigorous monitoring effort, using quadrats (1 meter-squared plots made from a durable material such as pvc pipe) in specific locations that are measured twice annually can give you a wealth of data on your project. A sound scientific monitoring protocol was used at the Goodyear Swams Sanctuary, and can be found here:

The monitoring protocol consisted of biennial monitoring, in spring and fall. The spring monitoring involved determining the abundance of Galerucella at each life stage (egg, larvae, and adult), in 1 meter-squared quadrats, along with estimation of percent cover of loosestrife, measurement of the five tallest loosestrife plants in the quadrats, and the amount of damage to the plants that could be confidently attributed to Galerucella feeding activity. Fall monitoring measured the same variables, along with native plant cover in each quadrat as well.

The above monitoring protocol was developed by Bernd Blossey, and can be found in the paper Impact and Management of Purple Loosestrife (Lythrum salicaria) in North America: ( ) and at Bernd Blossey’s site:

This paper, and indeed a large portion of Bernd Blossey’s published works, are all excellent sources of information on invasive species biocontrol programs. He is currently working at Cornell University, and his webpage can be found here:

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