Midwestern Canyons

With few exceptions, the Midwest is extremely flat.  Illinois, for instance, is the third flattest state in the country, and central Illinois is the flattest part.  Excluding the Illinois River Valley and Sangamon River Valley, there is virtually no significant elevation change in this region.   This makes areas like Starved Rock State Park or Matthiessen State Park a virtual wonder.  Cool north-facing canyons hold geologic and floral rarities for this part of Illinois.

At first I was extremely happy to have this sort of place in Illinois.  Then I noted a trend.  In Indiana sit Turkey Run and Shades State Parks.  The same ecotype, north-facing canyons and rarities both botanical geological.  And then I start reading about Hocking Hills State Park in Ohio, which is similar, although not exactly the same.

Is there a canyon-filled, popular state park in every Midwestern state?  And what is the equivalent in Michigan and Wisconsin?

Glacial meltwaters carved these canyons, it is said. That must have been a decently-sized flood.  I find it curious that at each of these places I have visited,  hemlocks grow wild, whether naturalized or not. (At present, I am delayed by several causes from determining anything related to the hemlocks that grow in Starved Rock.  I understand that most of my readers are probably people who see my blog linked on Blue Jay Barrens,  Steve Wilson's excellent blog.  Most of those who visit that blog I presume live east of me, and likely see Eastern Hemlocks (Tsuga canadensis) on a regular basis.  I, on the other hand, see such marvels as Prairie Trilliums (Trillium recurvatum)  in the woods nearby and find them extremely common.  I understand that this is a rare species anywhere east of Indiana, so to each his own treasure.)

To return to what I was saying, hemlocks are not common in the Midwest, and thus dwell exclusively on such sites as Starved Rock and Shades State Parks.  Other rarities of such sites include Canada yew (Taxus canadensis) and a diversity of fern species.  I am not implying that all these fern species are rare, but Starved Rock State Park, by itself, contains roughly a third of Illinois fern species.  I myself saw roughly eight species on my last trip, which was after a hard frost had killed off the leaves of most deciduous species.  One of the evergreen ferns was Asplenium trichomanes, which according to BONAP does not grow north of the Shawnee Hills in southern Illinois.  (There will be a future post entitled "When BONAP Is Wrong")

There are several reasons why Midwestern canyons are so biodiverse.

One is the fact that, as in my second to last post, the Midwest is the crossroads of the nation's plants and animals.  Starved Rock's summit, pictured below, holds both northern white pines (Pinus strobus) and the eastern red-cedar, (Juniperus virginiana), two plants from different parts of the world.  The cedar is a southern or western immigrant going north, and the pine is a dweller of the north at its southern limit.

 A second reason is that topography lends itself to diversity, obviously due to water-runoff.   Rocky upland areas provide dry habitat, while the bottoms of canyons are permanently wet.

Third comes temperature.  The cold rocks, shaded by trees, lead to a cool micro-climate with distinctly un-Midwestern  temperatures, while the hot rocks on the edges of bluffs provide a differing micro-climate entirely.  Plants such as White Pines, denizens of the north, can be found along these slopes.

All of this contributes to unique and diverse landscapes that are very worthy of exploring.