How was the creation of national parks - a network of protected lands - a response to these changes in migrations and land use?

The creation of a national park is an expression of faith in the future. It is a pact between generations, a promise from the past to the future. In 1916, Congress established the National Park Service to conserve the parks "unimpaired for the enjoyment of future generations." This act and the many others that have created the National Park Service and related programs echoes the promise of the Constitution "to secure the Blessings of Liberty for ourselves and our Posterity." We are that future, and we too must act on behalf of our successors. We must envision and ensure a system of parks and programs that benefits a new generation of citizens in a changing world.

Explanation: National parks are greatly admired. Inspiring us, uplifting our spirits, they serve as powerful reminders of our national origins and destiny. Yet there are opportunities unfulfilled. The parks should reach broader segments of society in ways that make them more meaningful in the life of the nation.