Invasive Plant Removal
Duration: 30 to 40 minutes
Vocabulary: invasive, native, multiflora rose, garlic mustard, indigenous, ecosystem
Summary: Students learn the difference between invasive and native species and learn to recognize certain common invasive plants.
Objectives: Students will gain a deeper understanding of how invasive species come to an area and why they are harmful. They also understand that, while humans can cause the problem of introducing an invasive species to an area, they can also work to solve it.
Materials: hefty garbage bags or other container for collecting pulled plants, gloves, hand shears (optional), grass seed
As people started traveling around the world and trade occurred between different areas, invasive species became more and more of a problem, and continue to be to this day. An invasive species is any play or animal species that is not indigenous to an area and that causes harm to the natural habitat. It might cause this harm by changing the soil, or taking up too many resources so that native plants can’t grow.
A native species, on the other hand, is a plant or animal that has lived in an area for along time and are well adapted to it. Native plants and animals also form relationships with each other based on the long period of time they have spent sharing the same space. Together, they form an ecosystem that is specific to that area. Most species that come in from outside do not do well in a new environment because they are not well adapted to it. For example, a polar bear would not do well in the tropics, and a palm tree wouldn’t do well in Northern Canada. There are some species, however, that DO adapt well to a new place and have a tendency to take over, driving out the native inhabitants.
Some invasive species were brought in by humans for food or medicine. Foxes were introduced by people to Australia purely so they would have something to hunt for sport. Other invasive species attach themselves to ships or imported goods, and spread around that way.
Because invasive species often do not have natural predators, they can grow/breed unchecked and push out native species.
Ask students what they think of when they hear the word “invasive.” What are some examples of invasive species that have been damaging to natural habitats? Are there any species that have gone extinct because of invasives? Ask them what measures they would take to get rid of an invasive species that was taking over an area.
This activity focuses on two common invasive plant species, garlic mustard and multi-flora rose. Garlic mustard was originally brought here from Europe for herbal purposes, and multi-flora rose was brought over from Asia to prevent soil erosion along cattle fields. Unfortunately, it grows too quickly and takes up other desirable land as well. Multi-flora rose spreads by “layering,” which is when the plant grows straight up until it eventually falls over to the ground, and then the tip of the plant sends out roots and it grows up again. This means that their root systems can be enormous and difficult to remove.
One of the primary ways to control both of these invasive plants is to pull them up and plant something else on top of the space to compete with it.
Teach students how to identify these two invasive species using the pictures in the Handouts section. Divide them in to groups of 2 or 3 and give them a bag, gloves, and a container of grass seed. Students will identify garlic mustard and/or multi-flora rose plants, pull them up, throw them away in the trash bag, and sprinkle grass seed in its place. The pulled up plants can be used in a compost pile, or discarded.
Ask students to describe what makes an invasive plant different from a native plant. Why do we consider invasive plants “bad?” What are some ways we can get rid of them?
Have students form teams to debate the question of “Should we stop invasive species or not.” For example, one side could argue that we must protect native species, while another could argue that nature is based on “survival of the fittest” and it is messing with the natural order. There are many other arguments related to this topic on both sides of the issue (i.e. do you remove them if they are human-introduced but not if they occurred naturally? how long does something have to be in an area before it is considered native? etc).