Thursday, November 12, 2009

Trip to southern Illinois prompts thoughts about invasive species

Trip to southern Illinois prompts thoughts about invasive species

Listen to the commentary
Real Audio : MP3 download

This past Saturday morning I found myself picking goldenrod seed from my favorite fleece pullover. I was waiting with another parent while our Boy Scouts prepared for a trip to Giant City State Park in southern Illinois. I remarked to him that it would probably be better for me not to bring along those seeds, which had gotten stuck on me at River Bend Forest Preserve the week before. Who knows what impact they would have, transported 200 miles from where they started?

That moment came back to me again and again on our trip, as I was reminded of the many ways people shape the world by moving plants and animals around.

Of course we were already not hauling firewood with us because we’ve gotten the message about emerald ash borer. That’s the small beetle from Asia that has killed tens of millions of North American ash trees since it arrived near Detroit via wooden packing crates sometime before 2002. Emerald ash borers fly only short distances—maybe half a mile from where they begin life—but they have spread hundreds of miles through the movement of infested nursery stock and firewood.

As we drove south I noticed more and larger stands of Phragmites australis, or common reed. This is an aggressive European strain of a wetland grass that squeezes out all other plant life where it becomes established in North American settings. And phragmites is equally happy in a roadside ditch or a high quality natural area. [Dense stands of phragmites bordering a pond in Champaign County. It's pretty to look at, but detrimental to wildlife.] With its tall, graceful stalks and its elegant plumes of seed, phragmites looks pretty until you think about how detrimental it is to wildlife. It is good for neither food nor cover, and it crowds out plants that are. As I gazed over the vast swaths of phragmites near Rend Lake, I found myself thinking how similar it looks to miscanthus, the Asian grass that’s now so heavily promoted as a potential energy crop.

Even during our time at Giant City State Park we were reminded that plants often behave badly when they’re introduced into new ecosystems, where the forces that would keep them in check at home are absent. At the trailhead for our hike on Saturday afternoon we found a boot brushing station, where visitors were asked to clean up their footwear before setting out. [Rest assured the Scouts were having fun at Giant City, not worrying about invasive plants.] The station was set up by the Illinois Department of Natural Resources as one component of its broad effort to maintain the natural character of the park. According to IDNR naturalist Angie Kirkpatrick, invasive plants such as Japanese stilt grass and multiflora rose affect even the more remote areas of Giant City, and it’s a constant battle to keep them under control.

It seems to me the practical impact of a single boot brushing station at the beginning of a heavily-used trail would likely be pretty small. But I like the gesture it represents. In the same way we show respect for other people by not tracking dirt into their houses, we can show respect for the natural world by not thoughtlessly moving plants and animals (including insects) into places they don’t belong.