Osceola County: Rush Lake

A wetland at the Top Of Iowa seems like a good place to talk about…wind! The highest spot in the state (Hawkeye Point) is about 10 miles from this shallow lake/wetland outside Ocheyedan, in the far NW part of the state. The landscape nearby is dotted with wind turbines (did you know that Iowa is a leader in both wind energy production, and turbine manufacturing??). DSC_0014[1]

Rush Lake has a fringe of emergent vegetation (i.e., plants growing up from the water), presumably the shallow edge of the basin. The central area is open water. This is a sizable lake (about 350 acres/140 hectares) and in open country: wind-swept, no doubt. So…how are the “rushes” at Rush Lake affected by the wind? From a plant’s point-of-view, is the wind a blessing, or a curse?

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The clear answer is “Yes.” First, it is almost certain that wind is the reason those “reeds” (actually, Cattail, Typha) found this wetland in the first place. A cattail seed is attached to a bit of fluff, appearing under a microscope like a parachute. Wind-borne seeds blow everywhere, colonizing any newly-formed wetland (or ditch, or mud-puddle). All that wind blowing across the lake also helps oxygenate the water, and that aids the plant’s metabolism (all those cells down in the mud need oxygen, as so many cells do!).

The downside is the kinetic energy of that blowing wind; at times the wind moving across the water creates destructive wave action. I noted a section of interwoven cattail, torn from its mat and bobbing about in the open channel (visible in the photo above). A stiff wind blowing consistently across a water surface, can set up a considerable physical force, so these plants must literally contend with the force of nature. Their narrow, smooth, flexible leaves move well in the air and water currents. Quickly rooting wherever the wind plops the plant, is another important adaptation.

In the end, the wind is gonna blow, and we must all adapt. I can report that the Cattail is doing all right, here at the Top Of Iowa.

Author: Paul Weihe

Associate Professor of Biology at Central College, traditional author (Textbook of Limnology, Cole & Weihe, 5th ed.; Waveland Press), and now...blogger!

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