Nature across Wisconsin is not all the same. We can distinguish areas with a distinctive complex of climate, topography, soil, hydrology, flora, fauna, etc. These are often called "ecoregions," though the DNR calls them "ecological landscapes."
The biogeographical regions of Wisconsin have been distinguished in a number of ways.
US Forest Service: Ecological Subregions of the United States (in Wisconsin)
Wisconsin DNR: (16) Ecological Landscapes of Wisconsin
>> This is the system we will use in this class.