The Prairie Peninsula is an eastward projection of vegetation typically found in the American

prairie Prairies are ecosystems considered part of the temperate grasslands, savannas, and shrublands biome by ecologists, based on similar temperate climates, moderate rainfall, and a composition of grasses, herbs, and shrubs, rather than trees, as the ...

s into

Wisconsin Wisconsin () is a state in the upper Midwestern United States. Wisconsin is the 25th-largest state by total area and the 20th-most populous. It is bordered by Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake Michi ...

Illinois Illinois ( ) is a state in the Midwestern United States. Its largest metropolitan areas include the Chicago metropolitan area, and the Metro East section, of Greater St. Louis. Other smaller metropolitan areas include, Peoria and Rockfo ...

Indiana Indiana () is a U.S. state in the Midwestern United States. It is the 38th-largest by area and the 17th-most populous of the 50 States. Its capital and largest city is Indianapolis. Indiana was admitted to the United States as the 19th st ...

, and

Ohio Ohio () is a state in the Midwestern region of the United States. Of the fifty U.S. states, it is the 34th-largest by area, and with a population of nearly 11.8 million, is the seventh-most populous and tenth-most densely populated. The sta ...

. It is so named because it is an extension of grassland into the forests of the eastern United States. Natural fire regimes are considered to have helped maintain the eastern prairies. The Prairie Peninsula is considered an endangered ecosystem today. Through human settlement and farming, the peninsula has become heavily fragmented.

Geographic history

The Prairie Peninsula was mostly forested during the early Holocene. Prairie species began to thrive as aridity in the region increased between 10,000 and 8,500 years ago, displacing trees such as

elms Elms are deciduous and semi-deciduous trees comprising the flowering plant genus ''Ulmus'' in the plant family Ulmaceae. They are distributed over most of the Northern Hemisphere, inhabiting the temperate and tropical-montane regions of North ...

, ashes, ironwoods, and

sugar maple ''Acer saccharum'', the sugar maple, is a species of flowering plant in the soapberry and lychee family Sapindaceae. It is native to the hardwood forests of eastern Canada and eastern United States. Sugar maple is best known for being the prima ...

s. Trees recolonized the area between 8,500 and 6,200 years ago, such as oaks and hickories. The prairie ecosystem became dominant again around 6,200 years ago, despite the climate being less arid than it was between 10,000 and 8,500 years ago. It is hypothesized that the tallgrass prairie persisted through wildfires started by anthropogenic activity and by lightning. It has been theorized that the Native American use of fire in ecosystem management contributed to the formation and maintenance of the ecosystem. The formation of the peninsula is thought to be due to soil moisture retention that differs from the surrounding forests of the region. Deep soil moisture is not retained year-round, as the rates of

evapotranspiration Evapotranspiration (ET) is the combined processes by which water moves from the earth’s surface into the atmosphere. It covers both water evaporation (movement of water to the air directly from soil, canopies, and water bodies) and transpira ...

are high during the growing season. While shallow rooting grasses are less affected, tap-rooting trees are disadvantaged. The area receives 750 to 1200 mm of precipitation annually. However, periodic droughts, fire regimes, and browsing by elk and deer have contributed to the high mortality of colonizing tree saplings.

References

{{coord missing, United States Prairies Grasslands of the United States