A keystone species is a species within an ecosystem that influences most all other species in that system. If a keystone species is removed from the system, the system will either collapse or the removal will cause a dramatic change in the species composition of the system. Use the link below to access the ISEE Exchange website to explore a systems model related to the removal of the wolves, a keystone species in Yellowstone National Park.
Click on the paw to open the model and read the background of the story. Next, explore the box-and-arrow type model of the effect of wolves on vegetation in Yellowstone National Park.
Summarize the cause-and-effect model in words, including the effect on other animals and ‘ecosystem’ or ‘land health’.
What would happen to a system if wolves are removed from it?
Next, explore the box-and-arrow model.
What is the connection/relationship between wolves and moose & elk?
How did the removal of wolves from Yellowstone change the behavior of the elk and moose?
What is the indirect effect of wolves on the beaver population?
Why does this happen?
How are birds in the system affected?
How does the decline of beavers lead to a decline in aquatic insect populations?
What did the extermination of wolves affect the ‘health’ of rivers?
How did the presence of wolf kills (carrion) affect other animals?
How did reintroduction of wolves change the bison and elk behavior?
How did this affect the vegetation along rivers?
How did this affect the beaver population?
Why do you think we refer to wolves as ‘keystone species’ to Yellowstone?
What is a ‘keystone species’?
Finally, follow this link How Wolves Change Rivers to watch the following video provide by Sustainable Human for more talking points: