Duration: 30 to 60 minutes
Vocabulary: invasive, native, species, adaptation
Summary: Students help identify and remove invasive plants and plant native plants.
Objectives: Students gain a deeper understanding of what makes a species native vs. invasive, and some of the methods used to remove invasive species.
Materials: wedding gloves, trash bags, hand trowels, optional: grass seed, invasive species ID book
An invasive species is any species of plant or animal that is not usually from an area where it is now living. Specifically, it invades an area and causes harm to the natural habitat. There are some species that are not native but do not greatly harm native species. Those usually classified as invasive, however, often out-compete the native plants/animals and can cause them to die out.
A native plant or animal is one that has been in an area for a long time. For example, the plants in Pennsylvania are well adapted to the amount of sunlight and water they receive, because they have been growing here for many years. Additionally, native plants and animals usually have native predators that help keep populations in check. Together, this forms an ecosystem that is specific to Pennsylvania.
There are many examples of invasive species coming in to an area and driving out native species. One famous example is that of the cane toad. The cane toad was introduced to Australia in an attempt to control another species, a beetle that was eating farmers’ crops. It was brought from Hawaii to Australia, and quickly took over! It did nothing to stop the beetles, and instead has caused many problems for native species, as anything that eats it is poisoned. In the place where the cane toad is originally from, predators have adapted to this over time and can eat the toad, but in a place that has never had them before, the predators are unprepared.
Many invasive species are introduced to an area by human involvement. Some have come from other countries on ships, and some were purposefully introduced by humans for profit or pleasure.
Ask students what they think would happen if they took a cat and introduced it to a world where mice had never seen cats before. Would the mice be afraid? Would they know what to do? What might happen?
One of the primary ways of controlling invasive plants is pulling them up (everything, including the roots) and putting a native plant in its place that can compete with it.
Have students take a tour of the school grounds in search of invasive species. One of the most common invasive plants in Pennsylvania is garlic mustard. When students find invasive plants, they should pull them up by grabbing as close to the roots as possible. If the roots remain in the ground, the plant can grow back, so it is important to get it all!
After pulling up the invasive plants, have students sprinkle grass seed on the place where the old plants used to be.
Have students put the invasive plants they pull up into trash bags to be thrown away.
Have students explain why invasive plants can be harmful. Have them explain why most invasive species don’t have predators the way native species do.
Have students each choose a different invasive species and research where it came from and why it is harmful in its new environment.
Have students look for invasive species outside of school grounds on a field trip.