Objectives: Students will: 1) identify native and exotic plant and animal species through observation and research; 2) identify the effects of introduced species on ecosystems.
Materials: writing materials, field guides, reference material (newspaper articles, Web sites, natural resource agency material).
Background: Alien invaders, also known as non-native or exotic species are those plants or animals that have been brought into a new area. Examples in Wisconsin are purple loosestrife, garlic mustard, gypsy moth, and zebra mussels. While species often move from one place to another over time, natural land barriers have prevented indiscriminate movement. Humans have changed these barriers. For example, organisms and seeds can be transported in a ship's ballast water, on clothing, and in cars or on boats as we move from one place to another. In some cases, species are introduced on purpose. Purple loosestrife was brought to the United States from Europe in the 1800s for use as a landscape plant.
Non-native species tend to out-compete native species for resources. They lack natural predators and parasites to control them since they didn't evolve in these new areas.
The main objectives of this activity are for students to identify non-native plant and animal species and to examine the positive and negative effects of their presence.