The Chicago Region: A Unique and Distinguished Place to Explore Plants

The Chicago Region is a 22-24 county region at the base of Lake Michigan with some 2800 vascular plant species. This rich diversity is primarily because we occupy a transition zone between large-scale ecosystems), standing at the precipice and convergence of two major biomes (Temperate Grasslands and Temperate Broadleaf & Mixed Forests) with three distinct bioregions: the Northern Great Lakes Forests Bioregion from the Northwest, Tallgrass Prairie to the West, and Temperate Eastern Deciduous Forest. The term ‘ecotone’ is often used to name the transitional interface between two or more biomes or ecosystems.

From a top-down perspective, we might see the Chicago Region as part of a Natural Division, which is nested within a larger ecoregion, nested within a larger bioregion, nested within a larger subrealm, nested within the larger realm of Northern America:

1. Realm: Northern America
2. Subrealm: We are at the intersection of the Great Plains subrealm and Northeast American Forests subrealm
3. Biome: Temperate Grasslands, Temperate Broadleaf & Mixed Forests
4. Bioregion: The Midwestern Tallgrass Prairie & Forest Transition Bioregion; traveling East into Indiana we find ourselves in the Interior Plateau & Southern Great Lakes Forests Bioregion; traveling Northwest into central Wisconsin we find ourselves in the Northern Great Lakes Forests Bioregion
5. Ecoregion: Central US Forest-Grasslands Transition ecoregion
6. Natural Division: Northeastern Morainal Division
7. Ecosystem: depends on where you walk!
8. Plant Community: also depends on where you walk, but most likely (barring the persistence of asphalt, urbanization, and the lifeless lawns of suburban sprawl), we would hope to find Oak Savanna

Oak Savanna would be considered our unique ecotone or ecosystem that arises from this convergence highlighted by one of our primary keystone species, Oak (Quercus spp.)!

The major factors contributing to the transitions among biomes include soil composition, changes in temperature, & precipitation, among other factors.