The Upper Midwest forest–savanna transition is a
terrestrial ecoregion that is defined by the
World Wildlife Fund. An
oak savanna plant community located in the
Upper Midwest region of the
United States, it is an
ecotone (a transitional area) between the
tallgrass prairies to the west and the
temperate deciduous forests 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 and conversion to
agriculture.
Fire and disturbance
Historically,
wildfire has been the primary driver and determinant of the
forest dynamics in the plant community. Due to this the resulting
canopy structure has been relatively sparse (the
basal area ranges approximately from 4 to 29 meters
hectare−1). Presence and
biodiversity of plant species is largely controlled by the frequency of fire. Typical tallgrass prairie vegetation such as
grasses,
forbs,
shrub
A shrub (often also called a 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 ...
s, and
sedges, increase with an increase in the amount of fire, whereas tree density and basal area decrease.
After
European American
European Americans (also referred to as Euro-Americans) are Americans of European ancestry. This term includes people who are descended from the first European settlers in the United States as well as people who are descended from more recent Eu ...
settlement and the abandonment of fire as a land management regime, most savannas have been converted into
closed canopy woodlands, with
shade tolerant and
fire-intolerant
Fire ecology is a scientific discipline concerned with natural processes involving fire in an ecosystem and the ecological effects, the interactions between fire and the abiotic and biotic components of an ecosystem, and the role as an ecosystem p ...
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
Works
* ...
and
secondary succession species dependent on fire.
Species distribution
Trees:
* ''
Quercus macrocarpa'' (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 eastern United States. Sugar maple is best known for being the prima ...
'' (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 introdu ...
'' (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
A state forest or national forest is a forest that is administered or protected by some agency of a sovereign state, sovereign or federated state, or territory (country subdivision), territory.
Background
The precise application of the terms va ...
but comes under the administration of the states'
Department of Natural Resources organizations or federal entities such as the
Fish and Wildlife Service. Remaining intact habitat areas include:
*
Devil's Lake State Park, on the
Baraboo Range
The Baraboo Range is a syncline located in Columbia and Sauk Counties, Wisconsin. It consists of highly eroded Precambrian metamorphic rock. It is about long and varies from 5 to in width. The Wisconsin River, previously traveling in a north ...
in south-central Wisconsin
*
Savanna Army Depot
Savanna Army Depot was a installation, located on the eastern bank of the Mississippi River, in Carroll and Jo Daviess counties, around north of Savanna, Illinois. It was opened in 1917 as a proving and testing facility for weapons developed at ...
in extreme northwestern Illinois
* Parts of the
Upper Mississippi River National Wildlife and Fish 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 ease ...
in the
Driftless Area of southeastern Minnesota
*
Whitewater State Park
Whitewater State Park is a state park of Minnesota, United States, preserving a stretch of the Whitewater River surrounded by rocky bluffs. It is located in Winona County in the southeastern blufflands area of the state. The park features s ...
, also in the Driftless Area
*
Necedah National Wildlife Refuge in central Wisconsin
*
Horicon Marsh in southeastern Wisconsin
*
Kettle Moraine State Forest in southeastern Wisconsin
See also
*
List of ecoregions in the United States (WWF)
*
Cedar Creek Ecosystem Science Reserve – an
ecological research
Ecology () is the study of the relationships between living organisms, including humans, and their physical environment. Ecology considers organisms at the individual, population, community, ecosystem, and biosphere level. Ecology overlaps w ...
station specializing in
fire ecology and its effects on oak savannas run by the
University of Minnesota
*
Big Woods
*
Oak savanna
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