The Power of 0.0007

UrSpo recently left a great question in the comments. It bears a bit more examination than a simple answer in the comments section, so I'm responding in a full post.

Spo: I forget the % of actual prairie remains; and is it growing or shrinking?

The first part of the question is relatively easy. Over 99.9% of the prairie in Illinois has been destroyed (99.93% to be exact). This figure was arrived at from an inventory, compiled in the mid-1970s, of natural areas remaining in Illinois. The graphic that accompanies this post gives a partial illustration of just how small this is. The red area is 0.07% of the blue square. In the case of Illinois prairie, it’s important to recognize that the remaining fragments are not all lumped together in one single place. There are over 100 parcels of varying size left. To be an accurate illustration, the red section would have to be divided into more than 100 little bits, also of varying size, scattered in a seemingly random distribution across the blue field.

Faced with this staggering loss, it’s no surprise that people have been trying to save what’s left, and even to restore bits of land to their former ecological state. Which ties in directly to the Spo question. Sadly, even the identification of these tiny remnants of remaining prairie has only slowed the complete destruction. More than a dozen sites located in the initial inventory have been destroyed. So in some senses, the number has gotten smaller.

Counterbalancing this, ecological restoration activities have tended to make the number larger. But even this is not simple. In rare cases, people have managed to intervene at nearly the last possible moment. Invasive brush is removed from an area, fire is restored as the herbaceous vegetation recovers, and the tiny wisps of native vegetation that had nearly been choked out burst forth and a beautiful diverse ecosystem returns to life.

Much more frequently, the restoration ecologist is faced with the prospect of starting over. The invasive shrubs and trees are cleared, but unless the area is seeded with native plants, the future is an endless succession of weeds. Unfortunately, these prairie recreations are very different ecologically from remnant prairies. The floristic quality is lower. That is, the number of plant species present is lower, and those species that show up show a weaker fidelity to undisturbed prairies. The vegetative structure is also different. Animal species, particularly insects, are typically much less diverse.

What is the overall result of all of these trends? I don’t have hard, quantitative data. My guess is that the overall area covered with native prairie vegetation has increased slightly in the last 30 years, but that the area cloaked in very high quality vegetation has declined somewhat. It can be distressing to feel that no bit of original vegetation is truly safe, and that we will be left with bits and pieces of a poor imitation.

Restoration techniques are improving, and newer restorations show more promise of authenticity than some of the earlier efforts. Still, it can be frustrating when those with economic interests accuse conservation-minded folk of politically-motivated intransigence when we resist compromise on the 0.007% that’s still here. We won’t meet you half way? Hey, half way came and went a long, long time ago.