Invasive Species – Fact or Invasive Species – Fact or Fiction?Fiction?

NameNameDateDate

Fact or Fiction…All non-native species are invasive.

Brown trout

Rainbow trout

Fact or Fiction…If it is pretty or Fact or Fiction…If it is pretty or beneficial it can’t be a beneficial it can’t be a

problem.problem.

Dave Brenner, MI Sea Grant

Fact or Fiction…Biological Fact or Fiction…Biological controls should be avoided at controls should be avoided at all cost because the solution all cost because the solution may be worse than the initial may be worse than the initial problems.problems.

Kurt Stepnitz, Michigan State University

Fact or Fiction…By the time Fact or Fiction…By the time you notice the spread of an you notice the spread of an

exotic species, it is too late to exotic species, it is too late to control it.control it.

GLSGN Exotic Species Library

Fact or Fiction…All aquatic Fact or Fiction…All aquatic plants are weeds. plants are weeds.

WI Lakes Partnership

Fact or Fiction - It is natural for Fact or Fiction - It is natural for plants and animals to move plants and animals to move around. And since it is nature, around. And since it is nature, it’ll all even out in the end.it’ll all even out in the end.

WI Lakes Partnership

Fact or Fiction…All exotic Fact or Fiction…All exotic species are spread by “natural species are spread by “natural mechanisms such as birds and mechanisms such as birds and the wind”.the wind”.

Fact or Fiction…Some non-Fact or Fiction…Some non-native species are native species are

beneficial/desirable. beneficial/desirable.

Chinook and Coho Salmon

Fact of Fiction…Using only Fact of Fiction…Using only herbicides is preferred to hand herbicides is preferred to hand pulling specimens as a control pulling specimens as a control method or vice-versa.method or vice-versa.

Fact or Fiction…Herbicide Fact or Fiction…Herbicide use is always bad and use is always bad and

inappropriate. inappropriate.

WI DNR

Fact or Fiction…Wetland Fact or Fiction…Wetland invasive plants such as reed invasive plants such as reed canary grass and purple canary grass and purple loosestrife are only a problem loosestrife are only a problem in wetlands, and not upland in wetlands, and not upland habitats.habitats.

Fact or Fiction…Native species Fact or Fiction…Native species do not become nuisance or do not become nuisance or

problem species.problem species.

Fact or Fiction…If a plant is Fact or Fiction…If a plant is available for purchase at a available for purchase at a

garden center, it must not be garden center, it must not be invasive. invasive.

Water hyacinth

Fact or Fiction…Some invasive Fact or Fiction…Some invasive plants also have beneficial plants also have beneficial

uses. uses.

John Lyons, WI DNR

Fact or Fiction…A cattail marsh Fact or Fiction…A cattail marsh is a good example of a wetland is a good example of a wetland

community. community.

Fact or Fiction…It is okay to Fact or Fiction…It is okay to release unused live bait into a release unused live bait into a

water body.water body.

MN Sea Grant

Fact or Fiction…Commercial Fact or Fiction…Commercial fishing for carp or white perch fishing for carp or white perch is a common sense approach is a common sense approach to removing PCBs from Green to removing PCBs from Green Bay.Bay.

White Perch, John Lyons, WI DNR

Fact or Fiction…The decline in Fact or Fiction…The decline in yellow perch populations in yellow perch populations in Green Bay can be attributed to Green Bay can be attributed to exotic species like carp, white exotic species like carp, white perch and zebra mussels.perch and zebra mussels.

Illustration by Virgil Beck

Fact or Fiction…The Fact or Fiction…The introduction of invasive plant introduction of invasive plant species can add to the number species can add to the number of species in an area, which of species in an area, which will be good for biodiversity.will be good for biodiversity.

WI Lakes Partnership

Fact or Fiction…Zebra mussels Fact or Fiction…Zebra mussels can increase water clarity. can increase water clarity.

Fact or Fiction…The increased Fact or Fiction…The increased water clarity as a result of water clarity as a result of zebra mussel’s filtering zebra mussel’s filtering activities will benefit people activities will benefit people who live on, or recreate on who live on, or recreate on lakes. lakes.

Fact or Fiction…Zebra mussels Fact or Fiction…Zebra mussels will not do well in northern will not do well in northern Wisconsin lakes because the Wisconsin lakes because the water temperatures are too water temperatures are too cold. cold.

David Brenner, MI Sea Grant

Fact or Fiction…Zebra mussels Fact or Fiction…Zebra mussels densities will be higher in densities will be higher in euthrophic or nutrient rich euthrophic or nutrient rich waters where there is more waters where there is more food compared to oligotrophic food compared to oligotrophic or nutrient poor waters.or nutrient poor waters.

Fact or Fiction…It is inevitable Fact or Fiction…It is inevitable that zebra mussels will that zebra mussels will eventually infest all Wisconsin eventually infest all Wisconsin water bodies; therefore we water bodies; therefore we should not waste our time in should not waste our time in trying to control their spread.trying to control their spread.

Fact or Fiction…Diving ducks, Fact or Fiction…Diving ducks, an important predator of zebra an important predator of zebra mussels, are capable of mussels, are capable of effectively controlling their effectively controlling their populations.populations.

Fact or Fiction…When striped Fact or Fiction…When striped snails show up in a lake, it snails show up in a lake, it

must be zebra mussels.must be zebra mussels.

Fact or Fiction…Rusty crayfish Fact or Fiction…Rusty crayfish are no longer spreading to new are no longer spreading to new

waters in Wisconsin. waters in Wisconsin.

Jeff Gunderson, MN Sea Grant

Fact or Fiction…Rusty Crayfish Fact or Fiction…Rusty Crayfish can only move through water. can only move through water.

WI DNR

Fact or Fiction…Rusty crayfish Fact or Fiction…Rusty crayfish are only carnivorous feeders are only carnivorous feeders (animal matter feeders), and (animal matter feeders), and therefore only affect the fish therefore only affect the fish population by eating eggs and population by eating eggs and fry, small adult or juvenile fish, fry, small adult or juvenile fish, and dead fish on the bottom. and dead fish on the bottom.

MN Sea Grant

Fact or Fiction…Because rusty Fact or Fiction…Because rusty crayfish can destroy large crayfish can destroy large amounts of aquatic vegetation, amounts of aquatic vegetation, they can and should be used to they can and should be used to control nuisance aquatic control nuisance aquatic plants, native or non-native. plants, native or non-native.

Richerson, Myriah and Amy Benson - USGS

Fact or Fiction…Once Fact or Fiction…Once introduced into new waters the introduced into new waters the negative impact of rusty negative impact of rusty crayfish is on going, and the crayfish is on going, and the damage done is permanent. damage done is permanent.

Roger Thoma

Fact or Fiction…Rusty crayfish Fact or Fiction…Rusty crayfish cannot take over a lake if a cannot take over a lake if a native crayfish species already native crayfish species already inhabits that lake. inhabits that lake.

Fact or Fiction…Increased Fact or Fiction…Increased numbers of crayfish either numbers of crayfish either native or non-native will native or non-native will improve the overall fishery in a improve the overall fishery in a lake. lake.

Richerson, Myriah and Amy Benson - USGS

Fact or Fiction…It is legal to Fact or Fiction…It is legal to possess live crayfish and possess live crayfish and angling equipment angling equipment simultaneously on any simultaneously on any Wisconsin inland waters. Wisconsin inland waters.

Fact or Fiction…Commercial or Fact or Fiction…Commercial or private harvest of any crayfish private harvest of any crayfish including rusty crayfish including rusty crayfish requires a permit. requires a permit.

Fact or Fiction…Commercial or Fact or Fiction…Commercial or private harvest of rusty private harvest of rusty crayfish can help control the crayfish can help control the problem. problem.

Fact or Fiction…The purple Fact or Fiction…The purple loosestrife problem in loosestrife problem in Wisconsin has already been Wisconsin has already been brought under control by past brought under control by past efforts of the Wisconsin DNR. efforts of the Wisconsin DNR.

Fact or Fiction…Once a Fact or Fiction…Once a biological control agent has biological control agent has been released into a purple been released into a purple loosestrife infested area, loosestrife infested area, nothing more needs to be done nothing more needs to be done to control the problem.to control the problem.

Fact or Fiction…Purple Fact or Fiction…Purple loosestrife can be eradicated loosestrife can be eradicated by physically removing the by physically removing the plant or by chemical plant or by chemical treatment.treatment.

Dave Brenner, MI Sea Grant

Fact or Fiction…The insects Fact or Fiction…The insects released to control purple released to control purple loosestrife have no predators loosestrife have no predators of their own. of their own.

Kurt Stepnitz, Michigan State University

Fact or Fiction…Once these Fact or Fiction…Once these insects run out of purple insects run out of purple

loosestrife, they will likely eat loosestrife, they will likely eat something else. something else.

Dave Brenner, MI Sea Grant

Fact or Fiction…Purple Fact or Fiction…Purple loosestrife (loosestrife (Galerucella)Galerucella) beetles are stationary.beetles are stationary.

Fact or Fiction…Enough of Fact or Fiction…Enough of these insects have already these insects have already been raised and released in all been raised and released in all the important locations across the important locations across the state to eventually control the state to eventually control purple loosestrife in Wisconsin.purple loosestrife in Wisconsin.

Doug Landis, MI Sea Grant

Fact or Fiction…Purple Fact or Fiction…Purple loosestrife doesn’t spread in loosestrife doesn’t spread in

my garden, so it will not my garden, so it will not spread to a wetland. spread to a wetland.

Dave Brenner, MI Sea Grant

Fact or Fiction…Purple Fact or Fiction…Purple loosestrife is legal to sell or loosestrife is legal to sell or

distribute in Wisconsin. distribute in Wisconsin.

Dave Brenner, MI Sea Grant

Fact or Fiction…Once Fact or Fiction…Once introduced into a new location, introduced into a new location, purple loosestrife quickly purple loosestrife quickly becomes the dominant plant. becomes the dominant plant.

Dave Brenner, MI Sea Grant

Fact or Fiction…Plants with Fact or Fiction…Plants with purple flowers growing along purple flowers growing along the shoreline means purple the shoreline means purple

loosestrife is present.loosestrife is present.

Fact or Fiction…The beetles Fact or Fiction…The beetles that have been used to control that have been used to control purple loosestrife are the same purple loosestrife are the same as the nuisance Asian lady as the nuisance Asian lady beetles.beetles.

Kurt Stepnitz, Michigan State University

Fact or Fiction…In a lake with Fact or Fiction…In a lake with just a few aquatic plants or just a few aquatic plants or structure for fish habitat, it structure for fish habitat, it would be a good idea to would be a good idea to introduce Eurasian water-introduce Eurasian water-milfoil.milfoil.

Dave Brenner, MI Sea Grant

Fact or Fiction…Drawing down Fact or Fiction…Drawing down an impoundment will kill an impoundment will kill Eurasian water-milfoil. Eurasian water-milfoil.

Fact or Fiction…The native Fact or Fiction…The native milfoil weevil is effective at milfoil weevil is effective at eradicating Eurasian water-eradicating Eurasian water-milfoil so we don’t need to milfoil so we don’t need to worry about controlling the worry about controlling the spread.spread.

Wendy Crowell, MN DNR

Fact or Fiction…There is Fact or Fiction…There is nothing we can do to control nothing we can do to control the spread of Eurasian water-the spread of Eurasian water-

milfoil. milfoil.

Ted Ritter

Fact or Fiction…If Eurasian Fact or Fiction…If Eurasian water-milfoil enters a lake via water-milfoil enters a lake via the boat landing, the launch the boat landing, the launch

site should be closed. site should be closed.

Dave Brenner, MI Sea Grant

Fact or Fiction…If Eurasian Fact or Fiction…If Eurasian water-milfoil has been found in water-milfoil has been found in a lake, in no time it will be so a lake, in no time it will be so choked with plants that the choked with plants that the lake will be unusable.lake will be unusable.

Fact or Fiction…The weevil that Fact or Fiction…The weevil that feeds on Eurasian water-milfoil feeds on Eurasian water-milfoil must be an invasive species. must be an invasive species.

Fact or Fiction…Eurasian Fact or Fiction…Eurasian water-milfoil has absolutely no water-milfoil has absolutely no

value.value.

Fact or Fiction…All species of Fact or Fiction…All species of milfoil are bad. milfoil are bad.

Northern water-milfoil, UW Herbarium

Whorled water-milfoil, UW HerbariumBoth native species!

Fact or Fiction…Rainbow smelt Fact or Fiction…Rainbow smelt are a native Wisconsin fish are a native Wisconsin fish

species.species.

John Lyons, WI DNR

Fact or Fiction…Smelt have no Fact or Fiction…Smelt have no impact on native fish impact on native fish

communities.communities.

John Lyons, WI DNR

Fact or Fiction…Smelt are only Fact or Fiction…Smelt are only found in big lakes like Lakes found in big lakes like Lakes

Michigan and SuperiorMichigan and Superior..

John Lyons, WI DNR

Fact or Fiction…Opening up Fact or Fiction…Opening up fisheries to smelt harvest will fisheries to smelt harvest will

control smelt numbers.control smelt numbers.

John Lyons, WI DNR

Fact or Fiction…Smelt are Fact or Fiction…Smelt are spread to inland lakes on the spread to inland lakes on the feet of ducks and other birds.feet of ducks and other birds.

Fact or Fiction…Reed canary Fact or Fiction…Reed canary grass is a beneficial forage grass is a beneficial forage

grass and should be planted in grass and should be planted in wetlands. wetlands.

Fact or Fiction…Reed canary Fact or Fiction…Reed canary grass was widely planted as grass was widely planted as “marsh hay” during the last “marsh hay” during the last

century.century.

Fact or Fiction…Forested areas Fact or Fiction…Forested areas do not have a reed canary do not have a reed canary

grass problem.grass problem.