Conservation Minnesota

Lessons from Starry Stonewort

We didn’t see this one coming.  Starry stonewort, a new invasive plant, was recently discovered in extensive areas of Lake Koronis (Stearns County) and in nearby Mud Lake.

Minnesota’s “State Management Plan for Invasive Species” didn’t even mention this plant; nor did the “Stearns County Rapid Response Plan for Invasive Species” (authored by me and Dr. Dan Molloy).

What could have been done differently?  What should have been done differently?

Probably nothing.

Starry stonewort has been in Michigan for over a decade, but it was only reported from the first lake in Wisconsin just last year.

In the Stearns County Plan, we outlined a detailed program for the early detection of invasive plants.  This may provide some useful perspective and illustrate just how difficult and expensive early detection really is.

In the plan we separate early detection of invasive plants and animals.

An early detection plan, to be meaningful, must detect an invasive plant introduction soon enough to have a reasonable chance to eradicate it or at least contain it to a small area.  To accomplish this, we outlined three levels of effort: 1) minimal using only volunteers, 2) intermediate and 3) intensive.

We used Lake Koronis as an example.  For the minimal effort, we estimated an annual cost of about $500.  For an intermediate effort, the estimated cost was up to $24,000.  For the intensive effort, the estimated annual cost was $60,000 to $95,000.

Here are a couple of local annual cost estimates for minimal, intermediate and intensive.

Lake Virginia:  $500; $1,200; and about $5,000.

Lake Independence:  $500; $7,000; and $35,000.

Lake Minnetonka (there could be some costs reductions at this scale):  $500; $117,000; and $323,000.

Here’s the bugaboo – the minimal effort is not likely to be sufficient for a meaningful response; the intermediate effort may be sufficient for containment, but only the intensive effort was sufficient for any realistic chance for containment.  Eradication under any circumstances is a stretch.

Simply, lacking a serious effort and a substantial financial commitment, there is not much chance of discovering new invasive plant infestations early enough to make much difference.

The story is even less hopeful for invasive animals.  At present, using current control options, the only invasive invertebrate animals for which eradication or containment has even been attempted are for zebra mussels and in the odds of their elimination or containment are slim because zebra mussels are almost always detected long after they have spread far and wide.

In the Stearns County Plan, we outlined the level of early detection effort (and cost) that would be required to increases the chances of detecting zebra or quagga mussels early enough to have some chance for containment.

Based on our evaluation in the Stearns County Plan, I estimated for the three examples above that the required intensive surveillance effort that might give a shot at finding zebra or quagga mussels early enough in a small area would cost: $180,000 (Virginia), $2.5 million (Independence) and $35 million (Minnetonka) per year.

Because of cost, I cannot recommend the kind of expensive intensive early detection efforts for mussels.  Further, I do not recommend attempting any early detection for other AIS animal because we have not control methods at this time.  So, even if detected early (a tall order), what would you do?  Unfortunately – there is nothing with much of chance at all for eradication or containment.

For reasons of high cost and slim likelihood of actionable early detection, we referred to such efforts as “early deception” in the Stearns County plan.  It is human nature to do something in the face of AIS threats, however hope ought to be tempered by reality.

Starry stonewort is in Minnesota to stay.  Other new invasive plants and animals are sure to get here too.  I think investing in research especially species-specific control measures is an appropriate long-term investment and strategy, but one that will take substantial resources and patience.

About Dick Osgood

Dick Osgood

Dick Osgood has authored numerous scientific journal papers, made hundreds of presentations at professional meetings, and recently co-authored his first book.  Now he’s working on his second book titled A Lake Manager’s Notebook.  Dick is a Certified Lake Manager and offers lake management consulting services through his business Osgood Consulting LLC.

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