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Goll-ly! Don't Take a Knapweed! The Impact of Nonnative Plants and Animals on Deer Mice

This article is from Issue Invasive Species - Vol. 8 No. 1.

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In the Western United States, spotted knapweed is one of the most widely found nonnative plants. Spotted knapweed was brought to the United States from Eastern Europe in the early 1900s. To control the spread of spotted knapweed, two types of gall flies have been released into areas with spotted knapweed. Unfortunately, these gall flies are not native to the arid grassland ecosystem either. The scientists wanted to study the effect of spotted knapweed and gall flies on the population of deer mice in arid grassland ecosystems. 

Welcome to the Invasive Species edition

Note to Educators

Invasive Species Lesson Plan

Student Notes Page

Reflection Section Answer Guide

Education Standards Correlations


Additional Resources for this Article:
Meet the scientists that contributed to this article:

"Science Topics" covered in this article:
  • Life Science
  • People and Science

"Environmental Topics" covered in this article:
  • Wildlife and Endangered Species (Educators)

Regions covered in this article:
  • Alaska
  • Forest Products Lab
  • Intermountain
  • International Institute of Tropical Forestry
  • Northern
  • Pacific Northwest
  • Pacific Southwest
  • Rocky Mountain
  • Southern
  • Southwestern

"Thinking About Science Themes" covered in this article:
In environmental science, scientists see no end to the problems they could study. Scientists often identify new problems to study from the findings of earlier research. When research is done, more questions always emerge at the end of a study. Scientists spend a lot of time reading and thinking about the results of previous research. They may also observe on their own what is happening. They then think about what information is missing. Often, scientists compare what they know with what is missing to develop hypotheses or predictions. This method of comparison is one way that science progresses. In this study, previous research had discovered information about the relationship between an invasive plant species and nonnative insects that might help to control it. Part of the insect's life cycle includes a larval stage. The scientists observed that a native mammal enjoyed eating these insect larvae. The scientists wondered if the substitution of the mammal's usual food with a nonnative food might affect the ecology of the whole area.
Specific "Thinking About Science" Themes:
  • Characteristics of Scientists
  • The Scientific Process

"Thinking About Environmental Themes" covered in this article:
An ecosystem is a community of plants and animals that interact with each other and with the nonliving environment. An ecosystem is not a specific size area. It can be any size one wishes to study. For the purposes of research, scientists often define an ecosystem by the plant or animal communities that live in a particular area. In this research, the scientists were interested in the ecosystem defined as an arid grassland (figure 1). One animal living within this arid grassland ecosystem is the deer mouse (figure 2). In an arid grassland ecosystem, deer mice usually breed and raise their young in the summer when food is most easily found. Deer mice eat a lot of different foods, including fruits, small nuts, insects, and spiders. Deer mice are prey for a wide variety of other animals, including snakes and owls. During the day, deer mice hide under rocks, in burrows, and use the thick grasses for protection. Using the deer mouse as an example, you can see that in an ecosystem many different plants and animals interact with and depend on each other.
Specific "Thinking About the Environment" Themes:
  • Ecosystems
  • Food chain

NSE Standards covered in this article:
  • Abilities necessary to do scientific inquiry (A)
  • Diversity and adaptations of organisms (C)
  • Nature of science (G)
  • Populations and ecosystems (C)
  • Regulation and behavior (C)
  • Risks and benefits (F)
  • Science and technology in society (F)
  • Science as a human endeavor (G)
  • Understandings about scientific inquiry (A)