Insights for Colorado

What can Colorado learn from wolf reintroductions in other places and from experts representing different perspectives?


What was the actual impact of wolves in and around Yellowstone twenty years later?

More than twenty years have passed since the reintroduction of the gray wolf into Yellowstone in 1995. Much scientific research continues to investigate their impact on the ecosystem and people. In this activity you will examine some of that research to compare the actual impact with the anticipated impact expressed by the public during the decision-making process.

You will be gathering and presenting information about the long-term impact of Yellowstone’s wolves to help anticipate possible impacts wolves could have in Colorado. 

  1. Divide into seven Wolf Reintroduction Research Teams. 
  2. Gather and summarize information about your topic by reading the articles below that are linked to the topic, reading articles listed in “More Articles: Latest Research in Yellowstone,” or independently searching for other relevant paper or digital texts or videos. As you read articles, organize relevant information such as: publisher, purpose of the article, the message the author wants to give the reader, etc. Separate out scientific facts, perceptions, and perspectives.
  3. Note how this research could help inform the decision-makers in Colorado.
  4. Prepare to present to other teams at a simulated Colorado Wolf Conference Poster Session. The presentations can be in any multimedia (visual and written) format. Include a summary of the Yellowstone impacts and an explanation of how this information could be helpful to Colorado.
  5. Share findings with the other teams, and make them available for the class to use as reference material during the remainder of the Quest.

Yellowstone's Wolf Reintroduction Research

Describe how the wolves’ status as an endangered species has changed since the 1995 reintroduction.

Describe how many wolf attacks there have been on people and pets in the states around the park (Wyoming, Idaho, Montana) since 1995.

Latest Research in Yellowstone

Articles continue to be published about wolves in Yellowstone as research continues. The articles below, or others you find online, will offer more recent research for all teams. An internet search might uncover other articles describing ongoing research.


What can Colorado learn from wolf experts representing Native American, rancher, and wildlife biologist perspectives?


What can Colorado learn from wolf impact in other places? 

Scientists and wildlife managers are examining the impacts that wolves have had in other ecosystems and communities around the country. Identifying similarities and differences between these other places and Colorado can help these people make stronger predictions about what might happen here.

Examine this table describing the features of other wolf habitat sites, and compare them with Colorado.

  1. Take a look at the headings of the columns and talk about what each means for Colorado’s wolf reintroduction (e.g., what does land management mean for Colorado’s wolf reintroduction?).
  2. For each location identify what, if anything, is similar to the reintroduction effort in Colorado? 
  3. Using the table below as a reference, create a chart or table that organizes: “Similarities between Colorado and other locations,” and “Differences between Colorado and other locations.” Additional information might be found in previous parts of the quest or online.
Species report from US Fish and Wildlife Service. https://ecos.fws.gov/ecp0/pub/SpeciesReport.do?groups=A&listingType=L&mapstatus=1 Trump administration proposes stripping protections for wolves across the nation from EarthJustice. https://earthjustice.org/news/press/2019/trump-administration-proposes-stripping-protections-for-wolves-across-the-nation

What is unique about the wolf-moose relationship on Michigan’s Isle Royale National Park?

  1. Get familiar with this northern Michigan island by reviewing the park map and information. Then compare and contrast the park with the mountains of western Colorado. 
  2. Check out the graphed data on The population biology of Isle Royale wolves and moose: an overview.
    • This data represents 50 years of wolf-moose dynamics on the island. Describe the wolf and moose population dynamics over time. What happened to the moose population when the wolf population increased? What happened to the wolf population when the moose population increased?
  3. The dilemma! What is the plight of these island wolves, and how are wildlife managers trying to resolve the dilemma? To answer these questions, read articles from 2013-14, followed by the 2019 article.
educator note

What was the actual impact of wolves on Yellowstone’s ecosystem and nearby citizens twenty years after the reintroduction? 

  1. The instructions for comparing the impacts of Yellowstone wolves on the ecosystem and people twenty years after reintroduction are adapted from the Part 3 lesson. Team 7 has been added to address the new research on trophic cascades, additional more recent articles have been added, and students are asked to describe how the research in Yellowstone could be helpful to decision-makers in Colorado. 
  2. Students can revisit other sections of EXPLORE to review the scientific evidence and debate around the effects of wolf reintroduction on a trophic cascade. This was discussed in Yellowstone without Wolves and in Wolves Return. The summary of the more recent scientific evidence is repeated below.

Scientists Debate: Do Wolves Change Rivers? 

It is widely agreed that taking wolves out of their ecosystems has caused a host of negative effects. The primary effect of wolf elimination was an increase in elk and deer populations that led to overgrazing of woody trees like willow and aspen. This led to a reduction in beaver populations and degradation of rivers and riparian habitat. The animals that depended on these rivers, like birds and fish, were then affected negatively as well.  When wolves were reintroduced in Yellowstone, scientists identified positive effects like the restoration of woody tree species, gradual increases in beaver populations, and the improved health of rivers. However, the debate is about whether or not wolves were the sole driver of this restoration¹ ² ³. Research has uncovered other factors that also seem to be contributing to the positive shift⁴ ⁵. Water availability, effects of wolves on other predators, and human hunting all have been shown to have an effect on elk populations, and require further investigation⁶.  This is an important reminder that interactions among wolves, their prey, and the ecosystems’ vegetation are complex.  The common ground shared between both sides of this scientific debate is that the accurate story is way more complicated than the trophic cascade’s top-down, wolves-causing-ecosystem-rebalance-all-by-themselves explanation. In the field of ecology, each organism in an ecosystem plays a unique role. When one organism is removed, the rest of the ecosystem can be affected. If people help an organism return, the goal is not to restore the ecosystem to what it used to be, but to try to help improve or maintain the health of the ecosystem as it is now. The case study of Yellowstone suggests that restoring wolves to the landscape can help restore balance. It also indicates that more research needs to be done.  Even if their role as a main driver of the trophic cascade is debated, scientists agree that wolves are important to the ecosystem, and that bringing them back could push the ecosystem further towards a healthier balance.

What is unique about the wolf-moose relationship on Michigan’s Isle Royale National Park?

If you want students to investigate another unique wolf population, Part 4 is a lesson of the wolves of Isle Royale National Park. These wolves migrated to the island on an ice bridge during a cold winter. Since neither land animals can leave the island until and unless another ice bridge forms, the wolf and moose are in a closed-system predator-prey relationship. The webpage includes articles for students to read. A suggested classroom procedure is in this lesson on p. 21-24.

Part 4: Isle Royale National Park, Wolves of Yellowstone Teacher Guide, p. 21-24.