Indiana Dunes: Where Ecology Was Born

The stretch of sand and forest along the southern shore of Lake Michigan here is not just scenic. It is, in a very specific scientific sense, the place where the modern discipline of ecology was invented.

In the eighteen nineties, a young botanist from the University of Chicago named Henry Chandler Cowles began making regular trips to the Indiana Dunes to study the plant life. He noticed something that seems obvious in retrospect but had never been formally described: the vegetation changed in a clear progression moving inland from the water. Right at the shoreline was bare sand. A little farther back came the first grasses, tough colonizers that could tolerate the wind and the shifting sand. Behind them came shrubs, then young trees, and then, farther inland still, old oak forests. What Cowles was seeing was time made visible in space. The plants closest to the water were the earliest stage of a process; the forests farther back were what those bare dunes would eventually become.

Cowles published his landmark paper in eighteen ninety-nine and used the dunes to show ecological succession in action. The idea that plant communities are not static, that they change over time in predictable stages moving toward a stable endpoint he called a climax formation, became one of the foundational concepts of ecology. The Indiana Dunes are sometimes called the birthplace of American ecology for this reason.

The dunes themselves were shaped by the retreat of the last glaciers about fourteen thousand years ago. Lake Michigan's waves and winds have been sculpting the sand ever since. The state park was established in nineteen twenty-six after decades of advocacy by conservationists who had watched industrial development claim most of the lakefront. It became part of the Indiana Dunes National Park in twenty nineteen. The park now supports more than fourteen hundred species of vascular plants, more biodiversity than many places far larger.