Hoptellectual: The Nature of Invasive Species

Two summers ago I went camping along the Mississippi River at Wyalusing State Park. The small park sits on a bluff on the Wisconsin side of the river and looks out towards the confluence of the Wisconsin and Mississippi Rivers.

One of the oldest state parks in Wisconsin, the whole place serves as a reminder of another time. Off in the distance you can see paddle steamers still coasting along the Mississippi visiting towns like DuBuque in Iowa and Prairie du Chien in Wisconsin while Native American burial mounds dot the bluff. The forest itself is old growth Wisconsin forests. Maple, oak and elm trees  provide a canopy with a bevy of maple saplings and birches jousting for sunlight underneath (Editor’s Note: Morel mushroom season is fast approaching and although instances of morels are rare, most mycologists and ecologists I’ve talked to recommend searching for the fungi under fallen elm trees. Fry in butter with a little bit of beer. Consume the beer alongside. Beware of false morels.). Overall, time and ecological succession have been good to the forest, allowing for steady growth of wildlife and strong nutrient flows. On the ground though, many feel invasive plants are starting to colonize.

It’s hard to go camping in Wisconsin without coming into contact with garlic mustard, the most prevalent invasive in the Upper Midwest, if not the United States. With dangerous looking leaves and a singular delicate flower at the tip, garlic mustard absorbs nutrients faster than most native plants and requires minimal effort for long-distance pollination (wash your dogs and wipe your feet). Though most conservationists treat the plant as a terrible invasive—which by some definitions, it is—the plant was originally used as a spice and the young plants can be used for delicious pesto.

The enemy. Or is it?

When walking through Wyalusing, it’s hard to imagine the park without garlic mustard. It demands on answer to one of the more perplexing questions in conservation biology and restoration ecology: When is an invasive species no longer invasive?

I’ve been working my way through Emma Marris’s Rambunctious Garden, a book trying to answer exactly that question. I liked the book right away as Marris emphasizes the importance of scaling and definition. It really allows us to see how flux and flow drive ecological systems, especially the academic discipline itself (Clements v. Gleason, the ecological bout of the century). Ecosystems constantly shape-shift, as if to stop is to die. Old gradients dissipate, and new ones form that often provide the nutrients for common invasives. Zebra mussels continue to punish the Great Lakes urban watersheds because they can handle all the nutritious effluents. Some see this as the tarnishing of the oft-idealized and hardly accurate “nature.” To me, it appears to be the next step.

The idea of “restoration ecology” always seemed kind of esoteric and pointless, especially considering the problem of invasives. Restoration ecology makes the assumption that there is some baseline that we can recreate with resources and understanding. Marris walks us through some tremendous and awe-inspiring restoration efforts, but is quick to point out the unnaturalness of these well-defined “natures.” Again, ecology is about changes in energy and nutrient gradients and those that survive are the ones that can make use of a current ecosystems resources. Invasives are often the next part of history, rather than a nuisance meant to be tamed.

I find Marris’ writing of particular interest because of my academic and professional interest in watershed renewal. Not unlike William Cronon, Marris asks us to consider how we can grow with this new nature rather than against it. What can we do as architects of our growth to make sure we make the most of urban green space? How can we use our knowledge of ecosystems and invasive plants to relieve overtaxed storm-water management facilities or clean the air? In an ironic sort of way considering the Clements and Gleason debate, it’s often about making sure everything is in its right place. Not a static right place, but the right place with potential to efficiently flow through a system.

Bored by ecological theory? Grab a pitcher of Ale Asylum, think about it, then Tweet (@midwestbeer), Facebook or email us (mwbeercollective@gmail.com).


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