How Wolves Change Rivers

Watch the following video clips then try to answer the questions below.  Until the last video, just try to pay attention and understand what is happening.  The last video sums it all up very well, so it’s a good one to use to answer the questions.

Video #1: https://www.youtube.com/watch?v=SAGEXDlUHDE

Video #2 (a great summary) https://www.youtube.com/watch?v=ysa5OBhXz-Q

Banff animal crossings: https://www.youtube.com/watch?v=9JX6cqME6Hw

1. What do wolves mostly eat in this protected park land?
2. What do elk like to eat? Try to be specific.
3. Tree roots near the river’s edge can keep the banks of rivers from eroding.  One type of tree is very good at helping the river this way. What type of tree did they focus on in these videos?
4. Wolves killed some of the elk, but what is more important is that the wolves changed the elk’s behavior.  What important behavior difference happened with the elk that ended up changing the rivers? (Hint: where would be good places and where would be bad places to hide from wolves?)
5. When the trees began to come back to the banks of the rivers, what other animals started to come back too?  List at least 4 here.
6.  Summarize the concept by filling in the blanks below:

Wolves disappeared from this protected park a long time ago.  This caused the r________s in the area to change.  The banks of the rivers were er____ing into the water too much.  This is because there were no r____ts from Aspen t_____s to hold the banks together.  The Aspen trees were gone because e___ were not afraid to go out into the open to eat the young trees.  So w_______s were brought back into the park and released.  The elk stopped coming out into the open to eat the trees by the r______rs.  The Aspen trees grew back and their roots stopped the rivers from ________ing.  This made the water clearer with less dirt in it.  The Aspen trees are a great habitat for many other animals such as song birds and beavers which slowly came back to the park.