Beyond the Dead River

by Carl Strang

The Dead River, in Illinois Beach State Park, is so named because most of the time it appears not to be flowing. It ends just shy of the edge of Lake Michigan, a sand bar between the two. Reportedly there are times when enough water comes into it that it breaks through this narrow barrier. The area south of that river is highly protected, and to enter it I needed a permit from the Illinois Nature Preserves Commission.

The Dead River and its extensions are free of invasive wetlands plants, though there are some unconnected wetlands in the area for which that is not the case.

The Dead River and its extensions are free of invasive wetlands plants, though there are some unconnected wetlands in the area for which that is not the case.

Sand savanna and prairie occupy the areas between the wetlands.

Sand savanna and prairie occupy the spaces between the wetlands.

My main goal was to survey the area for wetland singing insects. This was one of my last hopes for finding slender coneheads, but sadly there were none. I am beginning to think they have gone extinct in Illinois. On a much brighter note, I found that the area harbors a huge population of stripe-faced meadow katydids.

This male had developed his full facial color, but an intervening grass blade marred the portrait.

This male had developed his full facial color, but an intervening grass blade marred the portrait.

Profile view of a female.

Profile view of a female.

Illinois Beach remains the only place where I have found this wetland katydid, which even historically was never widely distributed.

I also heard a little chorus of nimble meadow katydids, out in the middle of a river offshoot in a patch of deeper-water arrowheads. There probably are other such groups elsewhere in the area. I plan to get a better idea of their numbers next year. This is the second place I have found them in the region, and the first for Illinois. I spent several days in my kayak this season searching for nimble meadow katydids in places in Illinois and Indiana where they were known in earlier decades.

Apparently the American lotus, shown here, and the yellow pond lily, which filled most of those sites, are too coarse for nimble meadow katydids.

Apparently the American lotus, shown here, and the yellow pond lily, which filled most of those sites, are too coarse for nimble meadow katydids.

I have found them among pickerel weeds and arrowheads, and historically they were known in patches of water knotweeds.

Water knotweed, like those others, is of intermediate coarseness.

Water knotweed, like those others, is of intermediate coarseness.

I suspect that the turbulence created by power boats favors the heavier plants that the insect apparently abhors. I wonder if Illinois Beach State Park also may harbor the last Illinois population of nimble meadow katydids. I have a few more places to check next year.

 

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