The Good News: Invasive species dying off because of cold snap

The good news about the cold:

DULUTH, MN — When it’s so cold your face hurts, and it’s hard to talk, it’s easy to forget there are actually some positives that come with these extreme cold temps.

We’re all-too-familiar with the Emerald Ash Borer in our region.

We’re also familiar with the bitter January cold, which right now, may be killing off the larvae of the invasive species.

“When temperatures get to about 20 below zero Fahrenheit, we see about 50% of the Emerald Ash Borer Larvae begin to die,” said Rob Venette, director of the Minnesota Invasive Terrestrial Plants and Pests Center with the University of Minnesota.

Researchers at the U of M have been studying the effects cold weather may have on the Emerald Ash Borer for years.

Experts say at 30 below and colder, as much as 90% of the ash borer larva could be dying off.

“Once ice begins to form in their bodies, that kills the insect,” said Venette.

The insects are not impacted by wind-chill. So, the actual temperature is what must be considered, which can oftentimes be colder than where insects burrow for the winter.

“Although we may be experiencing minus 40, it may only be maybe minus 35 under the bark of a tree. So, that helps the chances of an insect to survive,” said Venette.

Venette added, even though they are expecting large amounts of Emerald Ash Borers to die off as a result of this cold snap, that won’t impact how they survey the population in the spring.

Dr. Robert Sterner, director of the Large Lakes Observatory, says the cold could be putting a dent in the aquatic invasive species in Lake Superior, as well.

“The invasive species are coming from places in the world that typically aren’t as cold as we experience in a cold winter here,” he said.

Meaning the cold could be enough of a shock to kill at least a portion of them.

“We believe there is a relationship between warming conditions and the success of invasive species. So, weather like this is only good news as far as the native species go,” said Dr. Sterner.

And when lakes are covered in ice, water evaporation dramatically decreases, and typically, the water temperature is cooler in the summer.

“The combination of reduced winter evaporation and cooler summer surface temperatures means we keep more water within the lake volume,” said Dr. Sterner.

Increased water volume can be good for the shipping industry, and ecological systems within the lake. However, it is not very popular amongst shoreline homeowners as it can contribute to shoreline erosion.

More ice can also mean ice-out occurs later than normal, meaning colder lake water in the summer, which officials say could reduce the chances of algae blooms in lakes, as well.

That is contingent on the thaw and warming cycle in the spring and early summer.


2 thoughts on “The Good News: Invasive species dying off because of cold snap

  1. Seems we’re seeing evolution in action, the more cold hardy variants get a huge leg up for the next season, maybe enough to become the dominant variety.

  2. Good news about the Emerald Ash Borer dying off, as it’s been one of the most devastating invasives to hit my home state of Wisconsin. The Department of Natural Resources (WDNR) will continue doing their trapping program and limiting movements of infested wood from affected counties to those that aren’t affected, but a few more hard polar vortices will certainly help. And none of this is anything more than just cyclical weather patterns playing out in nature.

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