List of ecoregions in Arkansas

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The level III ecoregions in Arkansas are the South Central Plains (35), Ouachita Mountains (36), Arkansas Valley (37), Boston Mountains (38), Ozark Highlands (39), Mississippi Alluvial Plain (73), Mississippi Valley Loess Plains (74). (Compare to map of Level IV ecoregions.) Level III ecoregions, United States, Arkansas.png
The level III ecoregions in Arkansas are the South Central Plains (35), Ouachita Mountains (36), Arkansas Valley (37), Boston Mountains (38), Ozark Highlands (39), Mississippi Alluvial Plain (73), Mississippi Valley Loess Plains (74). (Compare to map of Level IV ecoregions.)

This list of ecoregions in Arkansas provides an overview of ecoregions in the U.S. state of Arkansas designated by the U.S. Environmental Protection Agency (EPA) and the Commission for Environmental Cooperation (CEC). The Commission's 1997 report, Ecological Regions of North America, provides a spatial framework that may be used by government agencies, non-governmental organizations, and academic researchers as a basis for risk analysis, resource management, and environmental study of the continent's ecosystems. [1] Ecoregions may be identified by similarities in geology, physiography, vegetation, climate, soils, land use, wildlife distributions, and hydrology. [2]

Contents

The classification system has four levels. Levels III, and IV are shown on this list. Level I divides North America into 15 ecoregions; of these, the entire state is within the Eastern Temperate Forests level. Subdividing the Eastern Temperate Forests, Arkansas is split among three Level II ecoregions: the Southeastern Plains, Ozark, Ouachita, Appalachian Forests, and the Mississippi Alluvial and Southeast USA Coastal Plains. Level III subdivides the continent into 182 ecoregions; of these, seven lay partly within Arkansas's borders. Level IV is a further subdivision of Level III ecoregions. There are 32 Level IV ecoregions in Arkansas, [2] many of which continue into adjacent areas in the neighboring states of Oklahoma, Mississippi, Missouri, Louisiana, Tennessee, and Texas.

The task of defining and mapping these ecoregions was carried out by the United States Environmental Protection Agency (EPA) Region 6, EPA-National Health and Environmental Effects Research Laboratory (Corvallis, Oregon), and the Multi-Agency Wetland Planning Team. [Note 1] The new classification system they developed may differ from previous frameworks developed separately by the agencies.

Arkansas is ecologically diverse. Though often simplistically split into halves from southwest to northeast, with "uplands" in the northwest half and "lowlands" in the southeastern half, the CEC system of levels reveals the diverse forests and floodplains, prairies and plateaus, ridges and river bottoms, and loess hills and lowlands of Arkansas. [2]


South Central Plains

36 Ouachita Mountains

The Ouachita Mountains near Caney Creek, Arkansas WestHannahMountain.png
The Ouachita Mountains near Caney Creek, Arkansas
Mount Magazine, the highest point in Arkansas Mt. Magazine State Park 026.jpg
Mount Magazine, the highest point in Arkansas
Buffalo national river steel creek overlook Buffalo national river steel creek overlook.jpg
Buffalo national river steel creek overlook

37 Arkansas Valley

38 Boston Mountains

39 Ozark Highlands

73 Mississippi Alluvial Plain

74 Mississippi Valley Loess Plains

Notes

Related Research Articles

<span class="mw-page-title-main">Boston Mountains</span> Highland ecoregion in Arkansas and Oklahoma, United States

The Boston Mountains is a Level III ecoregion designated by the Environmental Protection Agency (EPA) in the U.S. states of Arkansas and Oklahoma. Part of the Ozarks, the Boston Mountains are a deeply dissected plateau. The ecoregion is steeper than the adjacent Springfield Plateau to the north, and bordered on the south by the Arkansas Valley. The Oklahoma portion of the range is locally referred to as the Cookson Hills. There are several theories of how the mountains were named, though apparently none are related to the Massachusetts city.

<span class="mw-page-title-main">Ouachita Mountains</span> Mountain range in Arkansas and Oklahoma, United States

The Ouachita Mountains, simply referred to as the Ouachitas, are a mountain range in western Arkansas and southeastern Oklahoma. They are formed by a thick succession of highly deformed Paleozoic strata constituting the Ouachita Fold and Thrust Belt, one of the important orogenic belts of North America. The Ouachitas continue in the subsurface to the northeast, where they make a poorly understood connection with the Appalachians and to the southwest, where they join with the Marathon uplift area of West Texas. Together with the Ozark Plateaus, the Ouachitas form the U.S. Interior Highlands. The highest natural point is Mount Magazine at 2,753 feet (839 m).

<span class="mw-page-title-main">Piney Woods</span> Temperate coniferous forests ecoregion of the United States

The Piney Woods is a temperate coniferous forest terrestrial ecoregion in the Southern United States covering 54,400 square miles (141,000 km2) of East Texas, southern Arkansas, western Louisiana, and southeastern Oklahoma. These coniferous forests are dominated by several species of pine as well as hardwoods including hickory and oak. Historically the most dense part of this forest region was the Big Thicket though the lumber industry dramatically reduced the forest concentration in this area and throughout the Piney Woods during the 19th and 20th centuries. The World Wide Fund for Nature considers the Piney Woods to be one of the critically endangered ecoregions of the United States. The United States Environmental Protection Agency (EPA) defines most of this ecoregion as the South Central Plains.

<span class="mw-page-title-main">Gulf Coastal Plain</span> Coastal Plain in the Southern United States and Eastern Mexico

The Gulf Coastal Plain extends around the Gulf of Mexico in the Southern United States and eastern Mexico.

<span class="mw-page-title-main">Willamette Valley (ecoregion)</span> Temperate broadleaf and mixed forests ecoregion of the United States

The Willamette Valley ecoregion is a Level III ecoregion designated by the United States Environmental Protection Agency in the U.S. states of Oregon and Washington. Slightly larger than the Willamette Valley for which it is named, the ecoregion contains fluvial terraces and floodplains of the Willamette River system, scattered hills, buttes, and adjacent foothills. It is distinguished from the neighboring Coast Range, Cascades, and Klamath Mountains ecoregions by lower precipitation, lower elevation, less relief, and a different mosaic of vegetation. Mean annual rainfall is 37 to 60 inches, and summers are generally dry. Historically, the region was covered by rolling prairies, oak savanna, coniferous forests, extensive wetlands, and deciduous riparian forests. Today, it contains the bulk of Oregon's population, industry, commerce, and agriculture. Productive soils and a temperate climate make it one of the most important agricultural areas in Oregon.

<span class="mw-page-title-main">Columbia Plateau (ecoregion)</span> Xeric shrubland ecoregion of Canada and the United States

The Columbia Plateau ecoregion is a Level III ecoregion designated by the United States Environmental Protection Agency (EPA) encompassing approximately 32,100 square miles (83,139 km2) of land within the U.S. states of Washington, Oregon, and Idaho. The ecoregion extends across a wide swath of the Columbia River Basin from The Dalles, Oregon to Lewiston, Idaho to Okanogan, Washington near the Canada–U.S. border. It includes nearly 500 miles (800 km) of the Columbia River, as well as the lower reaches of major tributaries such as the Snake and Yakima rivers and the associated drainage basins. It is named for the Columbia Plateau, a flood basalt plateau formed by the Columbia River Basalt Group during the late Miocene and early Pliocene. The arid sagebrush steppe and grasslands of the region are flanked by moister, predominantly forested, mountainous ecoregions on all sides. The underlying basalt is up to 2 miles (3 km) thick and partially covered by thick loess deposits. Where precipitation amounts are sufficient, the deep loess soils have been extensively cultivated for wheat. Water from the Columbia River is subject to resource allocation debates involving fisheries, navigation, hydropower, recreation, and irrigation, and the Columbia Basin Project has dramatically converted much of the region to agricultural use.

<span class="mw-page-title-main">Snake River Plain (ecoregion)</span> Ecoregion in the northwestern United States

The Snake River Plain ecoregion is a Level III ecoregion designated by the United States Environmental Protection Agency (EPA) in the U.S. states of Idaho and Oregon. It follows the Snake River across Idaho, stretching roughly 400 miles (640 km) from the Wyoming border to Eastern Oregon in the xeric intermontane west. Characterized by plains and low hills, it is considerably lower and less rugged than surrounding ecoregions. Many of the alluvial valleys bordering the Snake River are used for agriculture. Where irrigation water and soil depth are sufficient, sugar beets, potatoes, alfalfa, small grains, and vegetables are grown. Elsewhere, livestock grazing is widespread. Cattle feedlots and dairy operations are found locally.

<span class="mw-page-title-main">Northern Basin and Range ecoregion</span>

The Northern Basin and Range ecoregion is a Level III ecoregion designated by the United States Environmental Protection Agency (EPA) in the U.S. states of Oregon, Idaho, Nevada, Utah, and California. It contains dissected lava plains, rolling hills, alluvial fans, valleys, and scattered mountain ranges in the northern part of the Great Basin. Although arid, the ecoregion is higher and cooler than the Snake River Plain to the north and has more available moisture and a cooler climate than the Central Basin and Range to the south. Its southern boundary is determined by the highest shoreline of Pleistocene Lake Bonneville, which once inundated the Central Basin and Range. The western part of the region is internally drained; its eastern stream network drains to the Snake River system.

<span class="mw-page-title-main">Ozark Highlands (ecoregion)</span>

The Ozark Highlands is a Level III ecoregion designated by the Environmental Protection Agency (EPA) in four U.S. states. Most of the region is within Missouri, with a part in Arkansas and small sections in Oklahoma and Kansas. It is the largest subdivision of the region known as the Ozark Mountains, less rugged in comparison to the Boston Mountains in Arkansas, the highest part of the Ozarks.

The Mississippi Alluvial Plain is a Level III ecoregion designated by the Environmental Protection Agency (EPA) in seven U.S. states, though predominantly in Arkansas, Louisiana, and Mississippi. It parallels the Mississippi River from the Midwestern United States to the Gulf of Mexico.

<span class="mw-page-title-main">Arkansas Valley (ecoregion)</span> EPA Level III ecoregion

The Arkansas Valley is a Level III ecoregion designated by the Environmental Protection Agency (EPA) in the U.S. states of Arkansas and Oklahoma. It parallels the Arkansas River between the flat plains of western Oklahoma and the Arkansas Delta, dividing the Ozarks and the Ouachita Mountains with the broad valleys created by the river's floodplain, occasionally interrupted by low hills, scattered ridges, and mountains. In Arkansas, the region is often known as the Arkansas River Valley, especially when describing the history and culture of the region.

<span class="mw-page-title-main">Western Corn Belt Plains</span>

The Western Corn Belt Plains is a Level III ecoregion designated by the Environmental Protection Agency (EPA) in seven U.S. states, though predominantly in Iowa.

The Southern Limestone/Dolomite Valleys & Low Rolling Hills is one of the 99 Level IV ecoregions in the continental United States, as defined by a collaboration between the EPA, USGS and USDA. It covers portions of Southwest Virginia, East Tennessee, Northwest Georgia, and Northeast Alabama. This Level IV ecoregion is nested within the larger Level I, II, and III ecoregions as follows:

<span class="mw-page-title-main">Southeastern Plains (ecoregion)</span> Level III ecoregion in the United States

The North American Southeastern Plains are a Level III ecoregion designated by the Environmental Protection Agency (EPA) in ten U.S. states. The region takes a U shape starting in western Tennessee, going south through eastern Mississippi, and forming most of Alabama. On the eastern side, the plains lie between the Appalachian Mountains and the coastal plains, forming central Georgia, South Carolina, and North Carolina. It forms part of eastern Virginia before terminating in Maryland.

<span class="mw-page-title-main">Mississippi Valley Loess Plains (ecoregion)</span> Level III ecoregion in the United States

The North American Mississippi Valley Loess Plains are a Level III ecoregion designated by the Environmental Protection Agency (EPA) in six U.S. states. The region lies primarily on the eastern border of the Mississippi Alluvial Plain, from the Ohio River in western Kentucky, through Tennessee and Mississippi, to Louisiana. A separate unit that includes Crowley's Ridge occurs west of the river in Arkansas and Missouri. It has been divided into four Level IV ecoregions.

References

  1. "Ecological Regions of North America: Toward a Common Perspective" (PDF). Commission for Environmental Cooperation. 1997. Retrieved January 15, 2018.
  2. 1 2 3 4 Woods, A.J.; Foti, T.L.; Chapman, S.S.; Omernik, J.M.; et al. (2004). "Ecoregions of Arkansas (color poster with map, descriptive text, summary tables, and photographs)" (PDF). Reston, Virginia: United States Geological Survey.