Marram Grass "Forest"
Marram Grass (seen here from a worm's eye view) is one of the first plants to take hold on a Great Lakes sand dune.
Once it takes hold, it's roots not only keep the sand from blowing away in the wind, the decaying grass begins to condition the sand. Once the sand has enough humus, it begins to support additional plant life, and that in turn offers more humus and shade so larger plants can survive.
Over hundreds or thousands of years, the dunes become rich in plant and animal life.