The River That Wolves Moved

What happens when one piece of a biome is removed? It can be catastrophic, even when it’s completely well-intentioned. This story of the Yellowstone wolves is a great example. Author Mary Kay Carson uses the structure of This is the House that Jack Built to show how interdependent flora and fauna in a biome are. In the early 20th century, all wolves were removed. This meant the elk had fewer predators and their numbers increased. With more elk, they decimated some plant life, particularly willows that prevented erosion which would muddy the waters. Since cutthroat trout need clear water to procreate, their populations fell. And on and on.

Carson, in addition to the poem, includes excellent sidebar information about the various flora and fauna affected. Her writing is conversational and will engage young readers throughout the whole book. Gorgeous illustrations by David Hohn use subtle colors and are filled with lots of details to keep youngsters’ eyes on the pages. The story is brought full circle and shows how a biome can be brought back when the missing component is reintroduced. This book belongs in every elementary classroom and library.