Hello, my name is Tom Alwin, and welcome to Invasive Species: The Basics. I’m an aquatic
biologist with the Department of Environmental
Quality working in the Aquatic Invasive Species Program.
Today I am going to introduce you to some basic invasive species concepts. Invasive
species impact every resident in Michigan to some degree, and it is important for everyone
to learn about Invasive Species and take action.
Invasive Species can come in many forms. It can be something that lives in the land
Or something that lives in the water. It can be a plant or an animal. It can even be a microbe.
The important thing to know about an invasive species is that it causes harm and is non-native.
HOWEVER, there are many non-native plants and animals that provide many benefits to Michigan.
The honey bee is a great example, native to Europe, it provides us with many benefits.
It's close cousin, however, the African Bee (or Killer Bee) is considered invasive due to its aggressive nature.
Generally speaking, the greater the invasive species population is, the greater the impact it will have.
A good example of this is feral swine, an invasive species that
can cause considerable damage to forests, crop lands, and water resources. They can
also host diseases that threaten humans, wildlife, and livestock.
While one hog will certainly cause damage, a group of swine can cause extensive damage.
Invasive species damage can be categorized into three main areas: the economy, the ecosystem,
and human health. Invasive species can have a negative economic
impact in two main ways. The first is economic loss, which is loss that does not
involve physical damage. An investment that results in losing money is an example of economic loss.
The second is management and control costs, which is just as it sounds: the cost to control or manage an invasive species.
To put this in perspective, lets talk about Eurasian water milfoil, an aquatic invasive
plant that is widespread in Michigan. A study conducted in Washington State focused on economic
loss caused by this invasive lake species. The study was published in 2014 and compared
property values around lakes without Eurasian watermilfoil to lakes with Eurasian watermilfoil.
They found that property values on lakes with Eurasian watermilfoil were 19% lower on average
than comparable property on non-infested lakes. In addition to reducing property value…
Eurasian watermilfoil can also inflict economic losses for businesses. Infestations that impede
recreation on a lake can hurt sales of local businesses. Additionally, Lake groups that
choose to combat the infestation to reduce the negative impacts incur management and control costs.
Once Eurasian Watermilfoil becomes established, management and control often become a long-term endeavor.
That's one reason why preventing the introduction of invasive species is vital.
The cost to manage and control aquatic plants using chemicals in Michigan has been estimated
to be $24 million/year. At the national scale… the economic costs
in terms of loss and management and control for all terrestrial and aquatic invasive species
is estimated to be as high as $137 billion per year.
So, it‘s clear that invasive species can have a big economic impact. Now let’s look at how they can impact the environment.
Once an invasive species becomes established
it will often displace native species and may even dominate the habitat.
Pictured here is garlic mustard, an herbaceous plant that grows in forests and urban areas.
Garlic mustard roots release chemicals that alter the soil, which harms native trees and
plants. Once established, it competes with tree seedlings for available light, nutrients
and water resources, preventing new trees. Garlic mustard has no known wildlife benefits.
Deer don’t eat it and it is toxic to some insects.
In addition to out-competing and/or crowding out native species, some invasive species are pests that feed
on and kill native species. The emerald ash borer is an example of a species established
in many parts of the state. Surprisingly, the larvae of the emerald ash
borer inflict the most damage, as it feeds on the inner bark of the tree. These little
things are responsible for killing tens of millions of ash trees in Michigan.
Where present, the emerald ash borer decimates ash tree populations.
But there are ash stands in the state that haven't been impacted by this invasive insect.
Unlike the emerald ash borer, the Asian Long-horn beetle has not been found in Michigan, but
has been observed in nearby states. It feeds on a number of trees, including maple, oak, and beech.
If it becomes established in Michigan, the damage it could do to forests and urban trees would be devastating.
Therefore, preventing the introduction of the Asian Long-horned beetle is crucial.
So now you know that invasive species can damage or ruin local economies and ecosystems—but
what about human health? Depicted here is a sea lamprey on a German horror film’s
promotional poster. Invasive species are sometimes sensationalized in pop culture as dangerous and life-threatening.
[Background: "Oh, that is hard, that is hard to get off."] This is rarely the case.
The truth is sea lamprey are a fish parasite and do not bother people. It’s not common for invasive species to directly harm human health.
There are however a few invasive species that
can directly harm a human. One such example is the sap of a plant called Giant Hogweed.
Upon contact with human skin, the sap can cause blistering and scarring. Thankfully
Giant Hogweed is rarely found in Michigan.
There are several native plant species that can be misidentified as Giant Hogweed. If
you think you found Giant Hogweed, avoid touching it .
If you want to learn more, there are many
great resources out there. A great place to start is michigan.gov/invasivespecies
This site provides information on invasive
species that are specific to Michigan. You can find info about: Laws, permitting, grants
volunteer opportunities and more. Remember: Even if an invasive species is widespread
it does not mean it is everywhere. So, please take care to ensure you are not spreading
invasive species. Thanks for watching!