How Wolves Change Rivers

flickr photo shared by Oregon State University under a Creative Commons ( BY-SA ) license


A perception of separation has emerged on a number of levels throughout our society; between humans and the natural environment, between species, cultures, each other and even within ourselves. Many people have lost the understanding that, if one part suffers, the whole suffers. By definition, elements of a system do not operate in isolation. But often, we seem to function as if they do. Of course perceptions vary widely depending on culture, politics and belief systems. Many societies which live in close proximity to the natural environment retain a sense of connection and sensitivity. However, in other countries much of the population has migrated to urban centres, subsequently losing the sense of connection to the natural environment. It is important that we all now remember that the universe as a whole is fundamentally interconnected - we are the universe and the universe is us.

The Yellowstone national park, USA gives us an iconic example for highlighting this. When the wolves that roamed the park were killed off by various ‘predator control’ programs in the 1920’s, the knock on effect of this human interference in the ecosystem dramatically compromised the health of the entire Yellowstone area, the park started to fall apart. However with the recent re-introduction of a small number of wolves to the area, not only has the ecosystem started to stabilize but the entire geography has started to build resilience.

In this exercise participants will take the case of Yellowstone national park and apply it to their own scenario in which they will ‘build an ecosystem’ role-playing animals, plants, humans, trees’ etc. Participants will gain an awareness of the interdependence and complexity of our planet's system.

Activity Type

Group / Theoretical 


90 minutes

Learning Outcomes

  • To understand the ecosystem as a whole

  • To understand the impact of environmental degradation

  • To understand the importance and role of each part of the system


Required materials and tools:

  • A device to watch the short video clip

  • Ball of string

Step-by-Step Instructions:

  1. Show participants the short “How Wolves Change Rivers” video clip on Yellowstone national park.

  2. Open a discussion guided by the following questions, recording down key words or themes on a flip chart for everyone to see [Allow 20 minutes for this step];

    1. What were some of the unpredicted impacts of the killing off of the wolves?

    2. What happened with the reintroduction of the wolves?

    3. What are the implications of this for other systems?

    4. What is the overall message of this case study?

  3. Play the game:

    1. Get participants to stand in a circle with one person standing in the centre with the ball of string [Allow 20 minutes for the whole string exercise].

    2. The person in the middle will name herself or himself as a particular animal, plant or other part of nature eg. rock, pond etc.

    3. Each person then names what animal, plant or object they are, try to pick within the same bio-region.

    4. The person in the centre hands the end of the ball of string to the person they are connected to. For example, if the person in the centre was a koala, they would hand the end of the ball of string to the person who is the eucalyptus tree.

    5. Continue along every person in the group. Each time they form a connection, they hold onto the string and pass on the end of the string to the person they’re connected to. Some things will end up connected to more than one other thing.

    6. Now go around the circle asking each person to tug on their string (this will represent this animal, plant, person, being taken out of the system), ask them to notice how many people feel it.

  4. After each person has had a turn in being (taken out) of the ecosystem ask the group to share about what they learned from the string exercise, recording key words or themes on flip chart paper for everyone to see.

Support Files

‘George Monbiot: For more wonder, rewild the world’ [More on the case of Yellow Stone Park]

Instructions for Submission

Upload 1 photos of the string exercise and/or used flip charts. Submit a written reflection of the process. Instructions on how to upload photos and how to submit things in Moodle can be found here: Instructions on Submission&Uploading

Instructions for Assessment

Provide feedback to at least one participant that has done this activity. Instructions on providing feedback can be found here: Instructions on Feedback

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