From memory... If I remember correctly, sea oats do not propagate using rhizomes while American beach grass does. This facilitates the lateral spread of the beach grass but not of the oats. As a result, areas where the American beach grass is dominant have dune walls with few gaps while areas where the sea oats are dominant have dunes with gaps. When a storm comes, it is then more likely to break through the dune wall and dump large amounts of sands behind the wall. Generally, areas in the North of North Carolina, where American beach grass is dominant, have thinner barrier islands. Areas in the South, where sea oats are dominant, have "thicker" barrier islands.
One of the park rangers had a talk about the sea turtles and much specifically about the loggerhead turtle. She mentioned a program from a group at the University of Georgia. In the program, they were collecting one egg from some of the turtle nests and analyzing its DNA. From these data, they could match nest from different location as being from individual turtles.
After getting back home, we did some internet searches. We think the group is probably that of Brian M. Shamblin and Campbell J. Nairn. Here are a couple interesting papers we found: