The Upper Midwest forest–savanna transition is a

terrestrial ecoregion An ecoregion (ecological region) is an ecological and geographic area that exists on multiple different levels, defined by type, quality, and quantity of environmental resources. Ecoregions cover relatively large areas of land or water, and c ...

that is defined by the

World Wildlife Fund The World Wide Fund for Nature (WWF) is a Swiss-based international non-governmental organization founded in 1961 that works in the field of wilderness preservation and the reduction of human impact on the environment. It was formerly named the ...

. An

oak savanna An oak savanna is a type of savanna (or lightly forested grassland), where oaks (''Quercus ''spp.) are the dominant trees. It is also generally characterized by an understory that is lush with grass and herb-related plants. The terms "oakery" or ...

plant community A plant community is a collection or Association (ecology), association of plant species within a designated geographical unit, which forms a relatively uniform patch, distinguishable from neighboring patches of different vegetation types. The comp ...

located in the

Upper Midwest The Upper Midwest is a northern subregion of the U.S. Census Bureau's Midwestern United States. Although the exact boundaries are not uniformly agreed upon, the region is usually defined to include the states of Iowa, Michigan, Minnesota and Wi ...

region of the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

, it is an

ecotone An ecotone is a transitional area between two plant communities, where these meet and integrate. Examples include areas between grassland and forest, estuaries and lagoon, freshwater and sea water etc. An ecotone may be narrow or wide, and it ma ...

(a transitional area) between the

tallgrass prairie The tallgrass prairie is an ecosystem native to central North America. Historically, natural and Historical ecology#Anthropogenic fire, anthropogenic fire, as well as grazing by large mammals (primarily bison) provided periodic disturbances to th ...

s to the west and the

temperate deciduous forest Temperate deciduous or temperate broadleaf forests are a variety of temperate forest 'dominated' by deciduous trees that lose their leaves each winter. They represent one of Earth's major biomes, making up 9.69% of global land area. These forests ...

s to the east. A part of the Upper Mississippi River basin, it is considered endangered with less than 5% of the original ecosystem remaining intact, due mostly to

overgrazing Overgrazing occurs when plants are exposed to intensive grazing for extended periods of time, or without sufficient recovery periods. It can be caused by either livestock in poorly managed agricultural applications, game reserves, or nature ...

and conversion to

agriculture Agriculture encompasses crop and livestock production, aquaculture, and forestry for food and non-food products. Agriculture was a key factor in the rise of sedentary human civilization, whereby farming of domesticated species created ...

Fire and disturbance

Historically,

wildfire A wildfire, forest fire, or a bushfire is an unplanned and uncontrolled fire in an area of Combustibility and flammability, combustible vegetation. Depending on the type of vegetation present, a wildfire may be more specifically identified as a ...

has been the primary driver and determinant of the

forest dynamics Forest dynamics are the underlying physical and biological forces that shape and change a forest ecosystem. The continuous state of change in forests can be summarized with two basic elements: disturbance (ecology), disturbance and ecological suc ...

in the plant community. Due to this the resulting canopy structure has been relatively sparse (the

basal area Basal area is the cross-sectional area of trees at breast height (1.3m or 4.5 ft above ground). It is a common way to describe stand density. In forest management, basal area usually refers to merchantable timber and is given on a per hectare ...

ranges approximately from 4 to 29 meters

hectare The hectare (; SI symbol: ha) is a non-SI metric unit of area equal to a square with 100-metre sides (1 hm2), that is, square metres (), and is primarily used in the measurement of land. There are 100 hectares in one square kilometre. ...

⁻¹). Presence and

biodiversity Biodiversity is the variability of life, life on Earth. It can be measured on various levels. There is for example genetic variability, species diversity, ecosystem diversity and Phylogenetics, phylogenetic diversity. Diversity is not distribut ...

of plant species is largely controlled by the frequency of fire. Typical tallgrass prairie vegetation such as

grasses Poaceae ( ), also called Gramineae ( ), is a large and nearly ubiquitous family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos, the grasses of natural grassland and species cultivated in ...

forb A forb or phorb is a herbaceous flowering plant that is not a graminoid (grass, sedge, or rush). The term is used in botany and in vegetation ecology especially in relation to grasslands and understory. Typically, these are eudicots without woo ...

shrub A shrub or bush is a small to medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees by their multiple ...

s, and

sedges The Cyperaceae () are a family of graminoid (grass-like), monocotyledonous flowering plants known as sedges. The family is large; botanists have described some 5,500 known species in about 90 generathe largest being the "true sedges" (genu ...

, increase with an increase in the amount of fire, whereas tree density and basal area decrease. After

European American European Americans are Americans of European ancestry. This term includes both people who descend from the first European settlers in the area of the present-day United States and people who descend from more recent European arrivals. Since th ...

settlement Settlement may refer to: *Human settlement, a community where people live *Settlement (structural), downward movement of a structure's foundation *Settlement (finance), where securities are delivered against payment of money *Settlement (litigatio ...

and the abandonment of fire as a land management regime, most savannas have been converted into closed canopy

woodland A woodland () is, in the broad sense, land covered with woody plants (trees and shrubs), or in a narrow sense, synonymous with wood (or in the U.S., the '' plurale tantum'' woods), a low-density forest forming open habitats with plenty of sunli ...

s, with

shade tolerant In ecology, shade tolerance is a plant's ability to tolerate low light levels. The term is also used in horticulture and landscaping, although in this context its use is sometimes imprecise, especially in labeling of plants for sale in nursery (ho ...

and fire-intolerant species dominating rather than the historic

primary Primary or primaries may refer to: Arts, entertainment, and media Music Groups and labels * Primary (band), from Australia * Primary (musician), hip hop musician and record producer from South Korea * Primary Music, Israeli record label Work ...

and

secondary succession Secondary succession is the secondary ecological succession of a plant's life. As opposed to the first, primary succession, secondary succession is a process started by an event (e.g. forest fire, harvesting, hurricane, etc.) that reduces an a ...

species dependent on fire.

Species distribution

Trees: * ''

Quercus macrocarpa ''Quercus macrocarpa'', the bur oak or burr oak, is a species of oak tree native to eastern North America. It is in the white oak section, ''Quercus'' sect. ''Quercus'', and is also called mossycup oak, mossycup white oak, blue oak, or scrub oa ...

'' (Bur oak) * ''

Tilia americana ''Tilia americana'' is a species of tree in the family Malvaceae, native to eastern North America, from southeast Manitoba east to New Brunswick, southwest to northeast Oklahoma, southeast to South Carolina, and west along the Niobrara River to ...

'' (American basswood) * ''

Acer saccharum ''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 the eastern United States. Sugar maple is best known for being the p ...

'' (Sugar maple) * ''

Quercus rubra ''Quercus rubra'', the northern red oak, is an oak tree in the red oak group (''Quercus'' section ''Lobatae''). It is a native of North America, in the eastern and central United States and southeast and south-central Canada. It has been intro ...

'' (Red oak)

Intact habitat

A survey in 1985 concluded that only of oak savanna remain, roughly 0.02% of what is estimated to have existed at the time of European settlement. Highly dispersed and fragmented, none of the present habitat falls under the designation of

National Forests National Forest may refer to: * National forest or state forest, a forest administered or protected by a sovereign state ** National forest (Brazil) ** National forest (France) ** National forest (United States) ** State Forests (Poland) ** The N ...

but comes under the administration of the states'

Department of Natural Resources This article lists subnational environmental agencies in the United States, by state. Agencies that are responsible for state-level regulating, monitoring, managing, and protecting environmental and public health concerns. The exact duties of ...

organizations or federal entities such as the

Fish and Wildlife Service A fish (: fish or fishes) is an aquatic, anamniotic, gill-bearing vertebrate animal with swimming fins and a hard skull, but lacking limbs with digits. Fish can be grouped into the more basal jawless fish and the more common jawed fis ...

. Remaining intact habitat areas include: * Devil's Lake State Park, on the

Baraboo Range The Baraboo Range is a mountain range in Columbia County and Sauk County, Wisconsin. Geologically, it is a syncline fold consisting of highly eroded Precambrian metamorphic rock. It is about long and varies from 5 to in width. The Wisconsin ...

in south-central Wisconsin *

Savanna Army Depot Savanna Army Depot was a installation, located on the eastern bank of the Mississippi River, in Carroll County, Illinois, Carroll and Jo Daviess County, Illinois, Jo Daviess counties, around north of Savanna, Illinois. It was opened in 1917 as a ...

in extreme northwestern Illinois * Parts of the

Upper Mississippi River National Wildlife and Fish Refuge The Upper Mississippi River National Wildlife and Fish Refuge is a , See also * Izaak Walton League * List of National Wildlife Refuges *Trempealeau National Wildlife Refuge Trempealeau National Wildlife Refuge is a National Wildlife Refuge ...

in eastern Minnesota and western Wisconsin *

Richard J. Dorer Memorial Hardwood State Forest The Richard J. Dorer Memorial Hardwood State Forest is a reserve of current and former forest in Minnesota's Driftless Area. Only of the land is state owned, with the remainder owned by private individuals and community groups, governed by ea ...

in the

Driftless Area The Driftless Area, also known as Bluff Country and the Paleozoic Plateau, is a topographic and cultural region in the Midwestern United States that comprises southwestern Wisconsin, southeastern Minnesota, northeastern Iowa, and the extreme ...

of southeastern Minnesota * Whitewater State Park, also in the Driftless Area *

Necedah National Wildlife Refuge Necedah National Wildlife Refuge is a National Wildlife Refuge located in northern Juneau County, Wisconsin near the village of Necedah. It was established in 1939 and is famous as the northern nesting site for reintroduction of an eastern U ...

in central Wisconsin *

Horicon Marsh Horicon Marsh is a marsh located in northern Dodge and southern Fond du Lac counties of Wisconsin. It is the site of both a national and a state wildlife refuge. Geological history Horicon Marsh was created by the Green Bay lobe of the Wiscon ...

in southeastern Wisconsin *

Kettle Moraine State Forest The Kettle Moraine State Forest is a state forest in southeastern Wisconsin. The chief feature of the reserve is the Kettle Moraine, a highly glaciated area. The area contains very hilly terrain and glacial landforms, such as kettles, k ...

in southeastern Wisconsin

References

{{DEFAULTSORT:Upper Midwest forest-savanna transition Temperate broadleaf and mixed forests in the United States Temperate grasslands, savannas, and shrublands in the United States Ecoregions of the United States Plant communities of the Eastern United States