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Horizon Education and Media Homeschool Science
Read the information ready for your diversity project.
Then scroll down and do the plant warfare lab to see how invasive species actually stop wilflowers from germinating by producing warfare chemicals. This is an optional extension.
Many plants and insects that we are familiar with are in fact invasive species that reduce local biodiversity. Since they were introduced from other ecosystems, they have no local pests or predators to keep them in check, so they can take over.
Restoration of local habitats include removal of invasives by weeding, biocontrol by releasing parasites from their original home that eat them, and purchasing of non-invasives by families for their yards and hillsides.
Families in California can use the PlantRight web site to help them find plants for their gardens that are alternatives to invasives.
The next lesson will include some of the following species in a project you will develop so read about them carefully on this page.
Black Mustard Brassica nigra blankets the hills with yellow and was introduced from the Mediterranean during the Mission period. Its young leaves are edible, like peppery spinach. Its roots leak chemicals that stop other plants from growing, and it crowds out native wildflowers.
Kyle Conle CC-BY-NC
Giant Reed Arundo donax is found near water and is also planted as a wind-break around agricultural fields. Although nurseries no longer sell it, the plant has taken over riversides throughout North America, stifling other plants. It was introduced from the Mediterranean to the Los Angeles area in the 1820s for roofing and erosion control.
dlbowls CC-BY-NC https://www.inaturalist.org/observations/223424335
The Goldspotted Oak Borer Agrilus auroguttatus is an invasive beetle that has killed over 80,000 oak trees in Southern California since arriving around 2004 from Arizona. Citizen Scientists are working with cities to track and eradicate the beetle if it appears in their neighborhood as it moves north.
Mike Lewis CC-BY-3.0 https://commons.wikimedia.org/wiki/File:Agrilus_auroguttatus.jpg
This invasive Brown Marmorated Stink Bug Halyomorpha halys has an egg of a Japanese parasite wasp on its back which is a biocontrol agent. The stink bug came from Asia and eats fruits and vegetable crops, as well as chaparral berries.
Hannah Robinson CC-BY-NC
The American Bullfrog is invasive to California and is a problem because it eats everything, including baby birds. The tadpoles are recognizable by their large size. The California Department of Fish and Wildlife Invasive Species program wants to hear from you if you see these frogs.
Chris Berry CC-BY-NC https://www.inaturalist.org/observations/46053304
The Nutria or Coypu Myocastor coypus is a very large water rodent that destroys river areas in the California Central Valley. They were introduced to the US from South America for the fur trade in the 1800s, and brought back illegally to California from Oregon recently. The California Department of Fish and Wildlife Invasive Species program removes them when notified.
Sam Fellows CC-BY-NC https://www.inaturalist.org/observations/36148519
Plant warfare lab
Plant warfare lab
Plants defend their space using chemicals!
Mustard greens and alfalfa sprouts are edible by humans, but they contain chemicals that reduce seed sprouting. This is a type of plant warfare.
In this experiment, alfalfa sprouts are used to show how they prevent regular packet seeds from sprouting.
You can also do this lab using mustard instead of alfalfa, and using wildflower seeds to see that invasive mustard also reduces California wildflower germination.
Courtesy KnoWeeds
From the desk of Hannah Robinson
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