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Kill the Aliens: Controlling Leafy Spurge


Mary Ann L. McLean
Natural and Mathematical Sciences
St. Mary’s University
Gary T. Grothman
Natural and Mathematical Sciences
St. Mary’s University


The majority of people in the world interact with nature in an urban setting. Management issues in urban parks tend to be more challenging than in “natural” parks for a variety of reasons, including heavy use, proximity to housing, local advocacy, protection of native species, and the common inclusion of water bodies such as streams, ponds or lakes. In this case study, students explore such complexities by focusing on the invasion of leafy spurge (Euphorbia esula L.) in Fish Creek Provincial Park in Calgary, Canada. Students research the most appropriate weed control methods for this urban context and share their findings by using the jigsaw method. An important aspect of this case is the use of grey literature (academic literature informally published) and students will need to evaluate various web sources during their research. The case is appropriate for courses in introductory biology, ecology or high school AP biology. Students should have some prior understanding of ecological concepts including competition, predation, herbivory, plant life cycles, and invasive species.


  • Distill significant information from grey literature.
  • Evaluate the quality of web sources.
  • Develop expertise in a topic.
  • Share expertise with other experts in related but different topics.
  • Understand the complexity of factors involved in controlling pest species.
  • Critically examine the pros and cons of different approaches to a real-world problem.
  • Negotiate to reach consensus on complex issues.


Invasive species; urban parks; park management; leafy spurge; Euphorbia esula; grey literature; conservation; weed; weed control; parks; Fish Creek Park; Calgary; Canada

Topical Areas

Ethics, Policy issues, Regulatory issues, Scientific argumentation, Social issues

Educational Level

High school, Undergraduate lower division, Undergraduate upper division



Type / Methods

Analysis (Issues), Discussion, Jig-Saw



Subject Headings

Biology (General)  |   Botany / Plant Science  |   Ecology  |   Environmental Science  |   Natural Resource Management  |  

Date Posted


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