"[T]he real dune-building action happens within inches of the ground. Even in a modest offshore wind, sand grains moving on the beach either roll and ripple along in a movement pattern called surface creep or actually play a kind of micro-geologic hopscotch called saltation, tiny grains slamming hard enough into a sequence of downwind neighbors to send them bounding into the air."
"Here, as in other coastal dune systems, a single blade of marram grass---or any of a handful of other colonizers---can begin the building of a giant. A tiny mound of blowing sand collects around the obstruction. More and more sand collects on the back side of the tiny mound, interrupting the force of wind enough for still more sand to drop out, until a ridge forms in a classic dune-ish shape: a long slope on the windward side, a steepdrop on the lee. In time beach grasses wil thoroughly colonize the new dune, stabilizing it with a webwork of roots and rhizomes."
"The Indiana Dunes National Lakeshore is the most fragmented unit in all the national park system, its protected patches broken by housing and industrial development. At just over 14,000 acres, it is a tiny national park, compared with placed like the Everglades (1.5 million acres) or Yellowstone (2.2 million acres). Yet the dune park harbors more total biological diversity than all but three national parks, and by far the highest plant diversity per acre. Here you can find arctic bear-berry hundreds of miles south of its usual boreal range, growing within feet of prickly pear cactus; you can find southern dogwood just over a rise from jack pine, normally a tree of the far-north woods."
A classic article on dunes
Henry Chandler Cowles, "The Ecological Relationships of the Vegetations of the Sand Dunes of Lake Michigan" .
Cowles studied the succession of plant communities, to climax forests, and first got the idea from hiking dunes and observing the changing plant communities. His study is the first example in America of the science of ecology, building on an idea that had been circulating among some contemporary European scientists that posited that ecosystems could change and evolve as species could. Cowles' was the first study to put these ideas to the test, with a detailed study of communities of plants and animals interacting in a specific environment over time.
On the Origins of the Name for Sleeping Bear Dune
|"The extraordinary biodiversity in rainforests and coral reefs is due in part to their complicated 'structure'---multilayered intermingling of micro-habitats. While old-fashioned shaded coffee farms [in Central America] are not as layered as natural forest, they offer much more structure than most crops---and surely more than coffee fields planted in full sun or even in groves of Inga trees."
Chris Wille, "The Birds and the Beans," Audubon Magazine, Nov./Dec. 1994: 62.
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