The Driftless Area: Is There A Future Without Knowing The Past?

    There is a common misconception that most of the beauty and allure of the Midwest landscape lays in the awe of the Great Lakes. Well, this idea is likely fueled by the fact that most Midwest states form what is known as the “Corn Belt”. In 2007, the Midwest consisted of 20,360,396 hectares of corn and 14,277,472 hectares of soybean, while the total area of agricultural land spans well over 127 million acres. Flat and homogenous landscapes of corn and soy are quite often what comes to mind when most Americans conceptualize the imagery of the Midwest. Though this may be a predominantly true narrative, there are many relatively small ecoregions that constitute the ecological diversity of the Midwestern landscape, one of which is a distinct region referred to as the Driftless Area. Extending across 4 state borders, this region is constructed by Southwestern Wisconsin, Southeastern Minnesota, Northeast Iowa, and a very small portion of Northwestern Illinois. It is known to have been skipped over by glacial drift at the end of the last Ice Age, which saved this relatively small region from the flattening effects of glaciation notable on the surrounding landscape. Diverse and karst topography allows for the watersheds to run cold with groundwater-dominant streams that support a world-class trout fishery. To the enticement of an angler’s solitude, the extent of national publicity that this region has received is strikingly low considering that the Mississippi corridor that flows through the Driftless Area is home to over 40% of waterfowl in the US, more than 300 bird species, and 260 species of fish. Not to mention that it functions as a massive recreational resource to more than 3 million people annually (more than Yellowstone), which produces a $6.6 billion annual recreational/tourism economy.

   Consequently, agricultural and cattle operation land expansion is undoubtedly a leading factor in ecological degradation and poses the largest threat to the ecological integrity of this region, which doesn’t align with the simultaneously high ecological and ecotourist economic value previously mentioned. Many ecological restoration efforts are actively combating degradation. In hopes to protect what is left and recreate an ecologically diverse and healthy future, it is vital that we consider the impact of perspective in this reconstruction. This may go without saying, but its worth reiterating so I’ll say it here for emphasis, “in order to know where we are going, first, we must know where we have been”.

    So, let's take a look at the past. The Shea et al. (2014) study attempts to reconstruct pre-Euro colonial vegetative composition of the Driftless Area. They bluntly recognize the critical role of “reference conditions and the development of knowledge regarding the processes that contributed to development of those conditions and their variability across landscapes” (Shea et al., 2014). Public Land Survey records were used to collect mid-1800’s land condition data. The data was analyzed in two intersectional groupings:

1. Vegetation cover and structure
• i.e. whether the composition of tree cover and species resulted in the existence of:
1. Prairie (No trees)
2. Savanna (Few trees)
3. Open Forest (Open canopy; substantial sunlight penetration to ground)
4. Closed Forest (Closed canopy; very little sunlight penetration to ground)
2. Statistical analysis of cover class associations with environmental factors, specifically: 
1. Soil Texture (silt, sand, or clay)
2. Topographic Roughness (diversity in elevation of the landscape)
3. Distance From Waterway

The cover classes are important for determining the demographic composition of the vegetative distribution to determine a relative biome type throughout the region. Complimentary to these data is the importance of understanding the conditions which led to the formation of these species compositions.

After collecting the data, Shea et al. found that pre-Euro colonial Driftless Area was predominantly comprised of oak savanna with 72.6% of all recorded trees being bur oak (Quercus macrocarpa), white oak (Q. alba), and black oak (Q. velutina) and 69.4% of the area was dominated by savannas. Importantly, they also found that their work similarly reflects other larger scale statewide assessments in other studies.

As a result of their ecologically distinct small-sale study Shea et al. was able to reconstruct a more precise representation of the tree cover and species composition of the area.  In alignment with greater precision was their ability to distinguish narrower assessments of environmental factors leading to the resulted vegetative composition. For example, this precision exposed that the prevalence of oak and the diverse oak cover classes, and being distinctly associated with savannas suggest a critical presence of low intensity fire in pre-Euro colonial eras as an Indigenous ecological management technique. Relevantly, they propose that variance of fire intensity and frequency has been known to have direct impacts on tree species composition; exemplified here by the absence of fire in oak savanna leading to mesophication. 

    This leads to comparatively reference present-day land cover in the Driftless Area. We know that today ~47% of the Driftless Area is agricultural land, 13% is developed, and 34% is forested, mostly in small fragments of closed forest. So, understanding that this study, as the first of its kind for this region, is intended to further inform management decisions is vital to recognize as a tool for future restoration efforts in the Driftless Area. The largest public concern and strongest political draw would undoubtedly be trout stream management and restoration. Shea et al. has already given us a outlook at potential future impacts by suggesting that hackberry (Celtis occidentalis), boxelder (Acer negundo), and honeylocust (Gleditsia triacanthos) are likely to increase in dominance. Strong efforts have been made to remove encroaching riparian boxelder communities and replace with prairie grasses, and more recently prairie cord grass strips have been planted as riparian buffers. This one area of interest where I could see Shea et al. offering a more critical look at restorative management. Although open to further interpretation, it is vital to critically and collectively inform future restoration. 

Work Cited

- Shea, M. E., Schulte, L. A., & Palik, B. J. (2014). Reconstructing vegetation past: pre-Euro-American vegetation for the midwest driftless area, USA. Ecological Restoration, 32(4), 417-433.

Image Sources

- https://www.extension.iastate.edu/news/driftless-region-beef-conference-jan-24-25

- https://www.mnopedia.org/thing/oak-savanna

- Shea, M. E., Schulte, L. A., & Palik, B. J. (2014). Reconstructing vegetation past: pre-Euro-American vegetation for the midwest driftless area, USA. Ecological Restoration, 32(4), 417-433.