Text modified from Abell et al. 2000. Freshwater Ecoregions of North America: A Conservation Assessment. Island Press, Washington, DC, USA. Additional text provided by Jennifer Hales.
Major Habitat Type
Temperate floodplain rivers and wetlands
Drainages flowing into
This basin includes the mainstem Mississippi River and its tributaries from its headwaters in Lake Itasca in north-central Minnesota to the confluence with the Ohio River at Cairo, IL where it flows into the lower Mississippi (Robison 1986).
Main rivers to other water bodies
Among the major tributaries of the Mississippi River are the Chippewa and Wisconsin rivers in Wisconsin, the Minnesota River in Minnesota, the Des Moines and Iowa rivers in Iowa, and the Wabash and White rivers in Illinois.
A part of the Mississippi complex, this ecoregion includes most of Minnesota, most of western Wisconsin, part of northeastern South Dakota, most of Iowa, parts of northeastern and southeastern Missouri, most of Illinois, and a small extension into northwestern Indiana. The ecoregion is defined by the drainage area of the Mississippi and its many tributaries.
The ecoregion falls within the Central Lowlands physiographic province. Much of the area was glaciated during the Pleistocene, and thus lacks the topographic diversity of other unglaciated areas. During this time the Driftless Area remained unglaciated, displaying greater relief, including many carved river valleys (Burr & Page 1986).
There are numerous lakes, with the heaviest concentration in the northern half of the ecoregion, which was covered by a continental glacier as recently as 10,000 to 15,000 years ago. This ecoregion also contains the Driftless Area, located in the northwest corner of Illinois, southern Wisconsin, and eastern Iowa; this area is completely surrounded by once-glaciated land, but was itself never glaciated. Common in this region (as well as in ecoregions  and , and ) are isolated wetlands called prairie potholes, which harbor a variety of aquatic species. These wetlands are so numerous that a full catalog of species inhabiting them has never been completed.
Terrestrial habitats include mixed forest, tallgrass prairie and forest-grassland mosaic (Ricketts et al. 1999). Prior to settlement, the ecoregion was dominated by oak-hickory, beech-maple forest and bluestem prairie, with tracts of northern hardwoods, spruce-fire, pine and maple-basswood forests (Burr & Page 1986). Today, much of the land has been developed and modified for agriculture.
Description of endemic fishes
Despite its diversity, the Upper Mississippi contains no endemic fish since the ecoregion was glaciated as recently as 10,000 years ago. Rare or near-endemic species of fish within the bounds of the region include the greater redhorse (Moxostoma valenciennesi), the silver lamprey (Ichthyomyzon unicuspis), and the pugnose shiner (Notropis anogenus).
Justification for delineation
Ecoregion boundaries are taken from Abell et al. (2000) and are based on subregions defined by Maxwell et al. (1995).
- Burr, B. M. and Page, L. M. (1986). "Zoogeography of fishes of the lower Ohio-upper Mississippi Basin" C. H. Hocutt and E. O. Wiley (Ed.) The zoogeography of North American freshwater fishes ( pp. 287-324 ) New York, New York, USA: John Wiley & Sons.
- Robison, H. W. (1986). "Zoogeographic implications of the Mississippi River Basin" C. H. Hocutt and E. O. Wiley (Ed.) The zoogeography of North American freshwater fishes ( pp. 267-285 ) New York, New York, USA: Wiley.
- Ricketts, T. H.,E. Dinerstein,D.M Olson;C.J. Loucks (1999). "Terrestrial ecoregions of North America: A conservation assessment" Washington, D.C.: World Wildlife Fund.
- Abell, R.,Olson, D.,Dinerstein, E.,Hurley, P. T.,Diggs, J. T.,Eichbaum, W.,Walters, S.,Wettengel, W.,Allnutt, T.,Loucks, C. J.;Hedao, P. (2000). "Freshwater ecoregions of North America" Washington, D.C.: Island Press.
- Maxwell, J. R., Edwards, C. J., Jensen, M. E., et al. (1995) \A hierarchical framework of aquatic ecological units in North America (Nearctic Zone)\ St. Paul, MN. North Central Forest Experiment Station, USDA Forest Service.
- Köppen, W. (1936). "Das geographische System der Klimate" Köppen W. and R. Geiger (Ed.) Handbuch der. Klimatologie ( (Vol. 1, pp. 1–44 ) Berlin, Germany: Gebrüder Borntröger.
- Kottek, M., J. Grieser, C. Beck, et al. (2006). "World Map of the Köppen-Geiger climate classification updated" Meteorologische Zeitschrift 15 pp. 259-263.
- Upper Mississippi River Conservation Committee (UMRCC) (2000) \A river that works and a working river: A strategy for the natural resources of the Upper Mississippi River System\ Rock Island, ILL. Upper Mississippi River Conservation Committee.