Page 4 - Impact Fall 2024

Minnesota’s waters, fish, forests, and other natural
treasures are under attack from invaders like carp,
spiny water fleas, zebra mussels, the emerald ash borer,
and buckthorn. Unchecked, these and other invasive
species would wreak havoc on our ecosystems and
economy.
CFANS experts and eco-champions Peter Sorensen,
Mike Schuster, Gretchen Hansen, and Robert
Blanchette work with state agencies to curb these
invaders and protect our state’s resources.
Grounding the flying fish: stopping invasive carp
Peter Sorensen, professor emeritus in the Department of
Fisheries, Wildlife and Conservation Biology, warns that
invasive carp, including the silver and bighead species,
are threatening Minnesota's waters. These carp, which
can decimate ecosystems by starving native fish, have
spread across the Mississippi River watershed, and
Minnesota could be next.
Sorensen's solution is a bioacoustic fish fence (BAFF),
a strategically placed wall of vibrating bubbles designed
to deter carp from advancing through river locks. The
BAFF uses sound and bubbles to confuse the carp,
preventing them from passing through. Alongside this,
Sorensen advises using hydraulic modeling and continued
carp removal to reduce their numbers. This system could
block over 95 percent of invasive carp, safeguarding
Minnesota's fisheries and water recreation.
Sorensen emphasizes the urgency: “Experience shows
it’s critical to stop them now. If we can, we’ll be the first
state to do so.”
Beating the buckthorn blues
Buckthorn, an invasive shrub from Eurasia, has been
crowding out native plants in Minnesota since its
introduction in the 19th century. It thrives in forests and
urban areas due to its dense foliage and rapid growth.
However, researchers like Mike Schuster from the
Department of Forest Resources are uncovering new
ways to control this invasive species.
Schuster's research challenges the belief that
buckthorn seeds remain viable in the soil for five to six
years. “We provided strong evidence that that was not
based on data,” Schuster explains. His team found that
most buckthorn seeds germinate within the first two
years, making long-term seed banks less of a concern.
Additionally, Schuster discovered that planting
fast-growing native species like wild rye grasses can
outcompete and “shade out” new buckthorn growth. His
work is being applied through the U of M’s Cover It Up
project, where volunteers and professionals are replacing
buckthorn with native species.
Moreover, Schuster's team found that using the
herbicide fosamine can effectively prevent buckthorn
stumps from resprouting, providing another tool in the
fight against this persistent plant. These combined
efforts are helping Minnesota make strides in controlling
buckthorn’s spread.
Invasive
species meet
their match