Controlling Invasive Species

Lake Ottawa: Managing through partnership
In partnership with the Michigan DNR and the Ottawa National Forest, CAC researchers led by David Lodge are working to control the invasive rusty crayfish in Lake Ottawa in Michigan’s Upper Peninsula.  The rusty crayfish, a crayfish native to the Ohio River Basin, has invaded Lake Ottawa and decimated the lake’s aquatic plants.  With less habitat, there are fewer fish.   The Michigan DNR, in consultation with researchers from CAC, recently instituted a “no-kill” regulation on smallmouth bass in Lake Ottawa.  Managers believe that, with the newly implemented catch and release only regulations for anglers, the number and size of smallmouth bass will increase over the next few years. Because the smallmouth bass eat crayfish, researchers believe that they can play a role in reducing crayfish populations, especially as the average size of bass increases and they are able to feed on larger, more reproductive crayfish.  The Ottawa National Forest has committed to trapping and removing the rusty crayfish in concert with the “no-kill” regulation.  The researchers and resource managers believe that removing the crayfish, while simultaneously encouraging the predatory smallmouth populations, will reduce crayfish numbers enough that to allow macrophyte and fish populations to return to a pre-invasion state. The project is underway and the lake is being monitored for signs of rejuvenation.  Efforts are also underway to plan a test of this hypothesis in multiple lakes.

Preventing Invasive Species - Risk Assessment

Like the restoration underway at Lake Ottawa, control of invasive organisms is difficult and expensive.  For some organisms there are no effective control measures.  For this reason, CAC research focuses strongly on preventing invasive species from being introduced in the first place.   Researchers are developing risk assessments that inform decision makers where the highest risk for invasions will occur.   By identifying high-risk pathways and organisms, scientists at the Center are able to inform managers and policy makers where interventions should be developed.  Furthermore, scientists are also evaluating the effectiveness of these interventions.  Finally, in working with economists, CAC researchers are now able to inform decision makers about the cost effectiveness of these interventions in both economic and environmental terms.

Risks from Shipping

Currently, CAC researchers led by David Lodge are developing other risk analyses in a project funded by the Great Lakes Protection Fund (GLPF). Some of the goals of this project include identifying which shipping lanes have the highest risk of introducing organisms that will become invasive in the waters of a ship’s destination. In conjunction with this, researchers led by biologist Jeffrey Feder and engineer Chia Chang are developing new genetic probe technology to the problem of detecting harmful species in the ballast tanks of ships.  Once high risk shipping routes are identified, researchers plan to use the genetic probe to test ballast water for the presence of unwanted organisms and pathogens, and better inform the management of ships’ ballast water.

Intervention in dispersal of species by boaters

In another component of the Great Lakes Protection Fund (GLPF) project, CAC researchers are developing models of overland spread for aquatic invasive species by recreational boaters in Michigan and Wisconsin.  These models, developed in the Lodge laboratory, will guide managers about where to place interventions using this information.  In addition, researchers are evaluating the effectiveness of various intervention methods, including boat washing, inspection, and education.  In aggregate, results of this project will inform managers about the most cost-effective intervention strategies to implement in which locations.

Species Screening

In recent years, CAC researchers in the Lodge laboratory have developed screening protocols for fishes and mollusks, and are working on similar tools for plants. In addition, in evaluating national screening tools for plants, researchers found them to be highly beneficial economically as well as environmentally.  For intentional introductions, such protocols allows managers to decide on a level of risk and then decide what species should not be introduced based on this risk level.  Tools such as this, if implemented in the US, would allow managers to systematically make decisions about what species should be allowed in trade.  Lodge, his collaborators, and partners in The Nature Conservancy, are working with the City of Chicago, with the Great Lake States, and with USDA and USFWS, to implement screening protocols that better protect freshwater resources and human welfare.

Other communication to policy makers

CAC researchers also communicate their research results directly to decision makers.  They have testified at a congressional hearing, served on the national Invasive Species Advisory Committee, addressed the media at the National Press Club, and met with members of congress and their staffs to suggest policy options based on scientific and economic studies.  A joint initiative of The Nature Conservancy’s, Great Lakes Program and the Center for Aquatic Conservation includes more efforts like these to inform both policy and management for preventing and controlling the growing problem of invasive species.

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