Reading Pictures

The Art of Catastrophe

To the photographer, this image is a study in shapes and colors.

To the ecologist, it’s a drama — stability versus catastrophe.

One dropseed grass plant dominates the scene. The scattering of maroonish dogwood leaves make up the rest of the context, with a variety of prairie flowers poking through.

But this isn’t exactly a prairie. If it were, there’d be more native grass mixed with the wildflowers. Instead, it’s a battle zone.

Any three or four of those sprouts of native dogwood shrubs could make enough shade to finish off the dropseed and the other prairie species. If you look carefully, you may be able to find such prairie plants as prairie dock (large leaves at 10:30 and 12:00 — if you imagine the dropseed as a clock), wild quinine (large leaves at 2:30 and 3:00), and heath aster (white flowers at 11:00).

But something has been killing back these shrubs. It may have been mowing, or fire. But if it was fire, it hasn’t been very regular for very long. With regular fire, prairie species dominate.

Much of what’s growing here doesn’t belong to the prairie. What we have, in addition to the dogwood shrub sprouts, is such shrubland wildflowers as wild coffee (five insect-eaten yellowish leaves at 2:00), and cream gentian (at 5:00, leaves only, flowers or buds eaten by the deer).

Unlike the prairie, shrublands are maintained by occasional, catastrophic fire. The shrubs grow bigger and bigger, blotting out most prairie species while making temporary habitat for a whole suite of birds and other animals. Then fire burns the shrubs off, and the process starts over again.

In this case, however, the prevalence of “weedy” species such as tall goldenrod (yellow) suggests that this area was formerly plowed or bulldozed. Yet as the recovery here shows, even bulldozing is not the biggest catastrophe for an ecosystem. There’s a more insidious kind. In the absence of intentional management for conservation, this area is likely to gradually lose almost all its plant and animal species to what’s called “unassociated woody growth.” When the ecosystem reaches that terminal stage, its few species of native and nonnative trees will support very little wildlife and biodiversity, and, for that matter, little opportunity for people to enjoy aesthetics or nature.

Thanks to Chicago Wilderness, there is a good deal less of that biggest catastrophe — the catastrophe of neglect — and a good deal more of those controlled burns that maintain stability in our majestic oak woods and prairies — even some of those friendly little catastrophic fires that keep shrublands vigorous and thriving.

Photo by Joseph Kayne.
Words by Stephen Packard.