Disjunct Distributions and Range Extremes
The Chicago Region is an area where floristic zones come together from all directions. Here the eastern deciduous forests meet the prairies and savannas from the west. Likewise, the northern and boreal habitats of bogs and swamp forests mesh with disjunct Atlantic coastal plain zones. There are many populations of vascular plant species found in the Chicago Region that are far-separated from their next closest populations. Their location seems out of place in terms of geography, but when the geologic history is taken into account, the biogeographic patterns make sense.
There is a major disjunct trend of the Atlantic Coastal Plain that appears in the western Great Lakes. There are discontinuous populations of plants (and invertebrate animals) that typically occur along the eastern and southeastern coast of the United States that are found in these inland areas (although coastal in respect to the Great Lakes).
There are several species in the Chicago Region that exist at the farthest part of their range. Some are at the southern-most extent from the Boreal Forests of the north. Other species are the most eastern representatives of the Great Plains of the west. Still others are at the most west edge of the deciduous forests of the east.
Localization in the Dune Areas
Many of the Chicago Region disjunct species and those at the extremes of their range occur in the dune areas close to Lake Michigan. Some examples of species which have their typical ranges nested in the Atlantic Coastal Plain, the northern Boreal Forests, or the Western Great Plains are listed at the right.
Atlantic Coastal Plain Disjunct Plants
Western Plains Plants
Information provided on this page applies to the Chicago Region and may not be relevant or complete for other regions.