15 Mart 2013 Cuma

Ecoregions Level 4: Sections - South Dakota

Ecoregions Level 4: Sections - South Dakota


Cross Section Map
This article identifies and describes Section-level ecological units for the state of South Dakota.
Sections are smaller and more homogeneous ecosystems that nest within Provinces. Each section is described by the predominant environmental and biological features used in its delineation, along with other pertinent or characteristic factors. These include physiography, geologic formations and naturally occurring vegetative cover types. These descriptions are not intended to be detailed, but rather to present enough information to describe the salient features of the units.
Information was obtained from various sources. Climatic information of provinces was extracted from information presented by Bailey (1995). Physical features and vegetation of many sections were abstracted from descriptions of map units (McNab and Avers, 1995), published sources (such as Garrison et al. 1977, Albert 1995), and other sources (U.S. Department of Agriculture 2000).
See the "Ecoregion Introduction" for complete information about Ecoregions.
SECTION 251A
RED RIVER VALLEY
Section 251A 
Geomorphology (landforms)
This Section is part of the Central Lowland geomorphic province. It forms the southern extension of a large, level lacustrine plain (Glacial Lake Agassiz) that extends far to the north and west into Manitoba, Saskatchewan, and Alberta. The plain is bisected by the Red River valley. Prominent alluvial fans formed where the Pembrina and Sheyenne Rivers entered the glacial lake from the west. Beach and morainal ridges border the Section on the east. Other features include kettles, wetlands, and dunes adjacent to the fans. Drainage is a modified trellis pattern; tributaries enter the Red River from uplands to the east and west. Geomorphic processes operating in the Section are fluvial erosion, transport and deposition. Elevation ranges from 825 to 1,150 ft (250 to 350 m). Local relief is 3 to 25 ft (1 to 8 m).
Lithology (rock types) and Stratigraphy (rock layer types)
Pleistocene (Wisconsinan) till (mixed glacial sediment) and lacustrine sand-siltclay- peat-muck cover bedrock to a depth of 200 to 400 ft (60 to 120 m). Quaternary (last 2 million years) alluvium (river sediment) covers the lacustrine sediments in the fans and major river valleys. Bedrock is predominently Archean granite, metasediments, and greenstone; Cretaceous shale and minor Jurassic sandstone overlap the Archean on the western and southern margins.
Potential Natural Vegetation
Kuchler types are bluestem prairie and northern flood plain forest, with the latter mapped in a narrow strip along the Red River and its major tributaries.
Fauna (animals)
Historically there were large populations of bison, elk, and antelope. Large predators included the prairie wolf and grizzly bear. (This Section marked the eastern-most range of both the grizzly bear and antelope). Other common species were the prairie chicken, sharptail grouse, prairie dog, and meadow lark. This area supported large numbers of both nesting and migrating waterfowl such as the mallard, pintail, greenwing teal, bluewing teal, and Cinnamon teal, canvasback and redhead ducks, as well as Canada and snow geese. Agriculture now dominates the Section; the major characteristic species are the introduced ringneck pheasant, cottontail rabbit, jack rabbit, coyote, red fox, and a host of species adapted to small grain agriculture. white-tailed deer are very common in the wooded draws and riparian (streamside) shrublands. The bison, elk, antelope, wolf, and grizzly bear have been extirpated (locally eradicated). Prairie chicken, sharptail grouse, and the prairie dog survive only in scattered remnants of suitable habitat. Many of the original waterfowl species have been substantially reduced (pintail, mallard, teal, and canvasback) but others (Canada goose and sandhill crane) are faring well, largely due to waste grain residues in agriculture operations.
Climate
Precipitation averages 18 to 23 in (470 to 580 mm.). About 40 percent occurs during the growing season. Precipitation in winter is almost entirely snow. Mean annual temperature ranges from 36 to 45°F (2 to 7°C). The growing season lasts 111 to 136 days.
Surface Water characteristics
Drainage is to the Red River of the north, which dissects the Section, and flows to the north. Drainage network is minimally developed. Streams meander through the level topography. Most wetlands have been ditched and drained for agriculture. Flooding is common in early spring, often intensified by frozen conditions to the north, causing water to back up. There are few lakes; they are most common in the southeast on a till (mixed glacial sediment) plain. Characteristically they are shallow and perched.
Disturbance Regimes
Fire, drought, and annual flooding are significant. High wind events are also common. Historically, bison grazing and ant activity caused important faunal modifications of vegetation and soils.
Land Use
The dominant land use is farming. Most wetlands have been drained for agriculture.
Cultural Ecology
Humans have occupied the area for at least 10,000 years, adapting their ways of life in a variety of changing environments. Conditions have ranged; from cool, wet, tundra supporting herds of open land grazing animals such as bison and caribou; through a warm, dry, savanna period when availability of water and aquatic resources was drastically altered; to the tall grass prairie of the present. People lived in small, nomadic groups and larger villages, changing their hunting, fishing, and gathering methods as environmental conditions changed, to enable the most efficient resource use. Horticulture has been practiced for about 1,000 years. Within the last 300 years, the near extinction of some species of fur-bearing mammals for the fur trade and cultivation of the land have significantly altered the environment. Today, farming and recreation are the major human activities affecting the ecosystem.

Data Source: United States Department of Agriculture, Forest Service.
Compiled by Eastern Region and Minnesota Department of Natural Resources.

SECTION 251B
NORTH-CENTRAL GLACIATED PLAINS
Section 251B 
Geomorphology (landforms)
This Section is part of the Central Lowland geomorphic province. It is mostly level to rolling till (mixed glacial sediment) plain. A series of low, sub-parallel, south to north and southeast to northwest trending morainal ridges is featured in the northwestern third of the Section. The Coteau des Prairies, a moderately dissected (cut by erosion), relatively high plateau with a much thinner till cover, is prominent in the northwestern portion. The Minnesota River's broad valley was created by the Pleistocene draining of Glacial Lake Agassiz. There are scattered lacustrine lowlands and outwash (glacier-melt sediment) channels as well. Elevation ranges from 750 to 2,000 ft (225 to 600 m). Local relief is generally 20 to 100 ft (6 to 30 m); it is higher in a few localized areas, notably the edge of the Coteau des Prairies.
Lithology (rock types) and Stratigraphy (rock layer types)
Pleistocene till (mixed glacial sediment), stratified drift, and lacustrine sand and clay mantle virtually the whole Section, from 30 to 300 ft (9 to 90 m) thick; most is Wisconsinan, but Illinoisan-Kansan covers the southwestern portion. A signifiant part of the area is capped with up to 20 ft (6 m) of Quaternary (last 2 million years) loess (wind-borne silt). Quaternary (last 2 million years) alluvium (river sediment) fills the valley of the Missouri River and other major drainages. Cretaceous shale, limestone, and sandstone form bedrock across most of the west half of the Section and in isolated outliers farther east. These units lap onto Archean granite and gneiss to the north, and Devonian (345-405 mya), Mississippian (310-345 mya), and Pennsylvanian (280-310 mya) limestone and shale to the south. Small but significant outcrops of Proterozoic quartzite occur across the Section, where they cap paleo-topographic high points. The Paleozoic rocks are exposed intermittently in the deeper drainages.
Soil Taxa (groups)
Types are mostly Mollisolls, with some Alfisols and Entisols. Temperature regimes are mostly mesic (avg. 8-15°C), with some frigid (avg. <8°C) in the north. Moisture regimes are mostly udic (perpetually moist), with some aquic (saturated) and some ustic (seasonally moist). Well-drained to moderately well-drained loamy soils formed in gray calcareous till (lime-rich mixed glacial sediment) of Des Moines lobe origin are dominant.
Potential Natural Vegetation
Kuchler type is mapped as almost entirely bluestem prairie, with a narrow corridor of northern flood plain forest along the Minnesota River, and a few fingers of oak-hickory forest along other drainages in the southern part.
Fauna (animals)
Historically there were large populations of bison, elk, and antelope. The major large predator was the prairie wolf. Other common species were the prairie chicken, sharptail grouse, prairie dog, and meadow lark. This was "pothole" country — areas of small, saucer-shaped wetlands. It supported large numbers of both nesting and migrating waterfowl, such as the mallard, pintail, greenwing, bluewing and Cinnamon teal, canvasback, and redhead ducks, as well as Canada and snow geese. Agriculture now dominates the Section; and the major characteristic species are the introduced ringneck pheasant, cottontail rabbit, jack rabbit, coyote, red fox, and a host of species adapted to small grain agriculture and woodlands. white-tailed deer are very common in the wooded draws and riparian (streamside) shrublands. The gray squirrel is common in woodlands, and recently the wild turkey has substantially increased as a result of re-introductions. The bison, elk, antelope, and wolf have been extirpated (locally eradicated). Prairie chicken, sharptail grouse, and the prairie dog survive only in scattered remnants of suitable habitat. Many of the original waterfowl species have been substantially reduced (pintail, mallard, teal, and canvasback) but others (Canada goose and sandhill crane) are faring well, largely due to waste grain residues in agriculture operations.
Climate
Annual precipitation averages 20 to 33 in (500 to 850 mm). About half falls during the growing season. Mean annual temperature is about 40 to 48°F (5 to 9°C). The growing season lasts 120 to 160 days
Surface Water Characteristics
Drainage is to the Mississippi via the Minnesota, Big Sioux, Des Moines, and Missouri Rivers. The drainage network is well established in the western part. The eastern part has relatively low frequency of shallow drainages. Natural lakes are rare, except in the Des Moines lobe in the eastern part. Many of these lakes tend to be shallow and perched. Small, saucer-shaped wetlands called prairie potholes were common, especially across the western part of this Section. Most wetlands have been drained for agriculture.
Disturbance Regimes
Historically, fire was the most common natural disturbance. Floods and tornadoes also occurred. Fire suppression has allowed woodlands to develop from what was originally oak openings or brush prairies.
Land Use
Current land use is dominantly agriculture.
Cultural Ecology
Humans have occupied the area for at least 10,000 years, adapting their ways of life in a variety of changing environments. Conditions have ranged; from cool, wet, tundra supporting herds of open land grazing animals such as bison and caribou; through a warm, dry, savanna period when availability of water and aquatic resources was drastically altered; to the tall grass prairie of the present. People lived in small, nomadic groups and larger villages, changing their hunting, fishing, and gathering methods as environmental conditions changed, to enable the most efficient resource use. Horticulture has been practiced for about 1,000 years. Within the last 300 years, the near extinction of some species of fur-bearing mammals for the fur trade and cultivation of the land have significantly altered the environment. Today, farming and recreation are the major human activities affecting the ecosystem.

Data Source: United States Department of Agriculture, Forest Service.
Compiled by Eastern Region and Minnesota Department of Natural Resources.

SECTION 251C
CENTRAL DISSECTED TILL PLAINS
Section 251C 
Geomorphology (landforms)
This is part of the Central Lowland geomorphic province. It is characterized by moderately dissected (cut by erosion), glaciated, flat to rolling plains that slope gently toward the Missouri and Mississippi River valleys, which bracket the Section on the west-south and east, respectively. Local relief is 20 to 165 ft (6 to 50 m). A minor anthropogenic (man-made) landform, strip-mined areas, exhibit hummocky or ridge-swale topography. Drainage is dendritic (branching); current geomorphic processes are fluvial erosion, transport and deposition, and minor mass wasting (landslides). Elevation ranges from 600 to 1,500 ft (185 to 450 m).
Lithology (rock types) and Stratigraphy (rock layer types)
Quaternary (last 2 million years) loess (unconsolidated wind-borne silt), as much as 25 ft (8 m) thick and thinning to the east, mantles most uplands. Pleistocene (pre-Illinoisan) till (mixed glacial sediment) and stratified drift underlie the loess and cover most bedrock up to 300 ft (90 m) deep, thinning to less than 30 ft (9 m) to the east and south. The Mississippi and Missouri floodplains have up to 150 ft (45 m) of unconsolidated Tertiary (2-63 mya) and Quaternary (last 2 million years) alluvium (gravel, sand, silt, and clay) overlying bedrock; other river valleys across the Section have somewhat less alluvial (river-borne) fill. Isolated outliers of Cretaceous shale and sandstone occur beneath the drift in the northwestern corner of the Section; Permian (230-280 mya) sandstone forms bedrock along the western margin; Pennsylvanian (280-310 mya) shale, limestone, and minor coal underlie most of the Section; and Mississippian (310-345 mya), Devonian (345-405 mya) and Ordovician (425-500 mya) shale and carbonate form bedrock to the east and south. Bedrock is exposed locally along the deeper drainages and in "windows" eroded through the unconsolidated surficial material.
Soil Taxa (groups)
Types are mostly Mollisols, some with claypan, with lesser extent of Alfisols. Moisture regime is mostly udic (perpetually moist), with some aquic (saturated). Temperature regime is mesic (avg. 8-15°C). Minerology is montmorillonitic or mixed. Soils are generally deep, rich, and dark-colored.
Potential Natural Vegetation
Kuchler vegetation types are mapped as dominantly mosaic of bluestem prairie and oak-hickory forest, with oak-hickory forest along drainageways. An estimated 60 percent of the land surface was bluestem (tall-grass) prairie, with bur oak and white oak savannas interspersed and in transitional areas. Upland forest (white oak-shagbark hickory) occurred on more dissected land, grading into bottomland forests and wet bottomland prairies along rivers.
Fauna (animals)
Prairie animals are now uncommon, since fewer than 20 natural prairies remain, all less than 20 acres in size. The major ungulates (hoofed mammals) were bison and elk, which have been extirpated (locally eradicated); white-tailed deer and cattle are prevalent today. The major predator is coyote (wolves and cougar were extirpated). Raccoon, badger, skunk, rodents. Open-lands birds like hawks, bobwhite quail, meadowlarks, sparrows, swallows are numerous; there are also savanna and woodland species such as turkey, and warblers. The numbers of prairie chicken, already low, declined recently. Introduced ring-necked pheasant are common. There are moderate numbers of reptiles and amphibians.
Climate
Mean annual precipitation is 30 to 40 in (760 to 1,020 mm). About two-thirds of this amount occurs during the growing season. Most winter precipitation is snow. Mean annual temperature is 50 to 56°F (10 to 13°C). The growing season lasts 160 to 180 days.
Surface Water Characteristics
A well developed and integrated dendritic (branching) drainage network is carved into the land surface. Natural lakes and ponds are rare or non-existent. Many streams that formerly meandered across broad valleys now are straightened by channelization and silted-in from agricultural run-off. A few bottomland wetlands have been preserved from drainage enterprises.
Disturbance Regimes
Fire and grazing by herds of bison and elk were most important in creation and maintenance of this landscape.
Land Use
Nearly all of this area is used for agriculture. About one-half is tilled crop land; the rest is used for haying or pasture. Tree cover is increasing.
Cultural Ecology
Ten thousand years ago, the river valleys of the Missouri and Mississippi were choked with floods from heavy rainfall and the outwash of northern glaciers. Interglacial periods were marked by dust storms. As the glaciers retreated, the Missouri River and its tributaries became a network of routes for water-traveling people to and from Missouri in any direction. Three thousand years ago there was widespread interaction with groups located along the Tennessee and Lower Mississippi Rivers. Two thousand years ago, people lived in villages located near the mouth of tributary rivers. One thousand years later, Cahokia, a major population center, existed with full-scale agriculture. The Missouri tribe continued agriculture and hunting and gathering until European settlement. Later, use of fire was discouraged to increase forest cover, grassland was converted for agricultural use, and strip mining for coal became prominent.

Data Source: United States Department of Agriculture, Forest Service.
Compiled by Eastern Region.

SECTION 331F
NORTHWESTERN GREAT PLAINS
Section 331F 
Geomorphology (landforms)
This area includes gently sloping to rolling, moderately dissected (cut by erosion) shale plains. There are some steep, flat-topped buttes, particularly in eastern Wyoming. Badlands with eroded escarpments (steep slopes) are in North Dakota and western South Dakota. Elevation ranges from 1,500 to 3,900 ft (458 to 1,200 m). This Section occurs on the Missouri Plateau and High Plains within the Great Plains physiographic province.
Lithology (rock types) and Stratigraphy (rock layer types)
This Section has soft Cretaceous and Lower Tertiary (2-63 mya) non-marine sedimentary rocks.
Soil Taxa (groups)
Soils include mesic (avg. 8-15°C) and frigid (avg. <8°C) Borolls and Ustolls, particularly in the northern, southern, and eastern parts of the Section. These soils are generally moderately deep to deep and have loamy to clayey textures. Argids, Orthents, and Orthids also occur, mostly in the central and western parts of the Section and on the badlands. These soils range from shallow to deep and generally have clayey textures.
Potential Natural Vegetation
Kuchler mapped vegetation as wheatgrass-needlegrass. Most of the Section has natural prairie vegetation, which includes western wheatgrass, green needlegrass, blue grama, needleandthread, and buffalograss. Bluebunch wheatgrass, little bluestem, and sideoats grama occur on shallow soils. Common shrubs in draws and along streams include buffaloberry, chokecherry, snowberry, and sagebrush. Ponderosa pine, juniper, and some aspen occur in North Dakota and on the Pine Ridge in South Dakota.
Fauna (animals)
Birds are dry grassland and badland species, and riparian (streamside) associates. Typical species are ferruginous hawk, golden eagle, sharp-tailed grouse and sage grouse, gray partridge, mourning dove, black-billed magpie, horned lark, western meadowlark, lark bunting, grasshopper sparrow, and chestnut-collared longspur. Riparian (streamside) or wetland associated species include dabbling duck, eastern kingbird, blue jay, brown thrasher, and yellow warbler. Species near the edge of their range include chimney swift; eastern, western and mountain bluebirds; dickcissel; field sparrow; and orchard oriole. Typical herbivores and carnivores include white-tailed deer, mule deer, pronghorn, and bobcat. Smaller common herbivores include the white-tailed jackrabbit, white-tailed prairie dog, and black-tailed prairie dog. Less common species associated with this Section includes bighorn sheep and the black-tailed jackrabbit. Rare species includes the black-footed ferret. Bison are historically associated with this Section. Herpetofauna typical of this Section are the snapping turtle, spiney softshell turtle, smooth green snake, and prairie rattlesnake.
Climate
Precipitation ranges from 10 to 20 in (250 to 510 mm), with more than half falling during the growing season. Winters are extremely cold with desiccating winds. Precipitation is snow. Climate is cold continental. Temperature averages 37 to 48°F (3 to 9°C). The growing season lasts 110 to 160 days.
Surface Water Characteristics
There are long, structurally controlled second and third order streams with low gradient, which are fed by high density, dendritic (branching) first order tributaries. Alternating hard and soft layers at low angles produce a complex pattern of resistant layers, temporary base levels, and headward and sideward erosion by undercutting. Ground water is scarce over most of the area but does occur locally in sand and gravel deposits. Major rivers include the Missouri, Cheyenne, Little Missouri, and Niobrara.
Disturbance Regimes
Fire and drought are the principal natural sources of disturbance.
Land Use
Dryland farming and livestock grazing occur on about 85 percent of the area. Some commercial timber harvests also occur.
Cultural Ecology
Reserved.

Data Source: United States Department of Agriculture, Forest Service.
Compiled by Northern Region
.

SECTION 331M
MISSOURI PLATEAU
Section 331M 
Overview
This section has mostly moderately dissected, unglaciated flat to slightly rolling plains with areasof badlands. Sandstones with some small areas of shales and coal form the geologic substrate. Vegetation includesGreat Plains grasslands and ponderosa pine cover types.

Data Source: United States Department of Agriculture, Forest Service.

SECTION 332B
WESTERN GLACIATED PLAINS
Section 332B 
Geomorphology (landforms)
Nearly level to undulating continental glacial till (mixed glacial sediment) plains occur, with areas of kettle holes, kames (layered sediment mounds), moraines (glacial debris deposits), and glacial lake plains. Glacial lake plains and some steep slopes are adjacent to streams. Elevation ranges from 1,000 to 2,000 ft (305 to 610 m). This Section is within the Central Lowland physiographic province.
Lithology (rock types) and Stratigraphy (rock layer types)
Glacial till (mixed glacial sediment) is underlain by Cretaceous marine sedimentary rock.
Soil Taxa (groups)
Soils include mesic (avg. 8-15°C) and frigid (avg. <8°C) Borolls and Ustolls, with poorly drained Aquolls in depressional areas. These soils are generally deep and range in texture from sandy to clayey.
Potential Natural Vegetation
Kuchler mapped vegetation as wheatgrass-bluestemneedlegrass. The natural prairie vegetation is mainly western wheatgrass, needleandthread, green needlegrass, and blue grama. Little bluestem is important on sloping and thin soils. Northern reedgrass, prairie cordgrass, big bluestem, and slim sedge are important species on wet soils. Northern flood plain forest occurs along major drainages.
Fauna (animals)
This Section is an important migration corridor for most species of waterfowl, but especially for American coots, snow goose, mallard, and blue-winged teal. Potholes or associated wetlands provide breeding habitat for many of these species and others, such as grebe and black-crowned night-heron. Where non-grassland habitat occurs, many birds associated with eastern avifauna nearly reach their westernmost extent; these include broad-winged hawk, ruby-throated hummingbird, Philadelphia vireo, cardinal, rose-breasted grosbeak, and rusty blackbird. Other typical species include greater prairie chicken, great crested flycatcher, eastern phoebe, blue jay, brown thrasher, dickcissel, and orchard oriole. Typical herbivores and carnivores include white-tailed deer, mule deer, and bobcat. Smaller common herbivores are the white-tailed jackrabbit, white-tailed prairie dog, and black-tailed prairie dog. Less common is the black-tailed jackrabbit. Bison are historically associated with this Section. Representative herpetofauna are the Great Plains toad, snapping turtle, spiney softshell turtle, smooth green snake, and prairie rattlesnake.
Climate
Precipitation ranges from 14 to 24 in (350 to 610 mm), with more than half falling during the growing season. Winter precipitation is mostly snow. Climate is cold continental with hot, humid summers. Temperature averages 39 to 43°F (4 to 9°C). The growing season lasts 110 to 155 days.
Surface Water Characteristics
The Missouri river is the major drainage. Few widely spaced perennial streams occur; there are some ponds and reservoirs. Sandstones yield high quantities of mineralized artesian water, while shales yield very little water.
Disturbance Regimes
Fire and drought are the principal natural sources of disturbance.
Land Use
Dryland farming occurs on about 65 percent of the area; the rest is grazed by livestock. A small amount of the area is irrigated.
Cultural Ecology
Reserved.

Data Source: United States Department of Agriculture, Forest Service.
Compiled by Northern Region.

SECTION 332C
NEBRASKA SAND HILL
Section 332C 
Geomorphology (landforms)
This area has rolling to steep, irregular sand dunes stabilized by vegetation, with narrow, elongated, gently rolling sloping valleys between dunes. Elevation ranges from 1,970 to 3,950 ft (600 to 1,200 m). This Section is within Fenneman and Johnson's Great Plains geomorphic physical division.
Lithology (rock types) and Stratigraphy (rock layer types)
This Section is composed of Tertiary (2-63 mya) sandstones, conglomerates, and minor shales; with Quaternary (last 2 million years) windblown dune sand and loess (wind-borne silt) covering the Tertiary sandstones and conglomerates throughout much of the area.
Soil Taxa (groups)
Soils include mesic (avg. 8-15°C) Psamments.
Potential Natural Vegetation
Mid and tall grass plant communities are present including Nebraska sandhills prairie (bluestem, sandreed). Kuchler classified vegetation as sandhills prairie, wheatgrass-bluestem-needlegrass, and, along major drainages, northern flood plain forest.
Fauna (animals)
Bison and wolves are historically associated with this section. Current large mammals include white-tailed deer, and mule deer and pronghorn antelope, for which this is the eastern range. Smaller mammals typical of the area are jackrabbit, cottontail, prairie dog, bobcat, and red fox. Typical year-round avifauna include bobwhite, greater prairie chicken, and mallard. Kestrel, eastern bluebird, swallow, and belted kingfisher are summer nesters. The northern extent of the sharp-shinned hawk's winter range lies in the Section, and the goldeneye duck is a winter resident. Typical herpetofauna are the snapping turtle, painted turtle, Great Plains toad, plains hognose snake, and bull snake. Catfish are common in rivers and ponds.
Climate
Precipitation ranges from 17 to 23 in (430 to 580 mm). Temperature averages 48 to 52°F (9 to 11°C). The growing season lasts 140 to 150 days.
Surface Water Characteristics
There are many small lakes and ponds and a few streams. Ground water is abundant and of good quality. The Niobrara, North and Middle Loup, Snake, Dismal, Elkhorn, Calamus, and Cedar Rivers flow through here.
Disturbance Regimes
Fire, insect and disease are predominant natural disturbances.
Land Use
Nearly all of this area is in large ranches, most of which are grazed. Use of sprinkler irrigation has increased over recent years.
Cultural Ecology
Reserved.

Data Source: United States Department of Agriculture, Forest Service.
Compiled by Compiled by Rocky Mountain Region.

SECTION 332D
NORTH-CENTRAL GREAT PLAINS
Section 332D 
Geomorphology (landforms)
There are nearly level to gently rolling till (mixed glacial sediment) plains with potholes and well defined dendritic (branching) drainage system. Moderate to steep slopes are adjacent to major valleys. River and creek valleys have smooth floors and steeps walls. Higher parts of tablelands are moderately sloping, but steeper areas occur on ridges and drainage ways. Drainages are well defined except in some undulating areas where eolian materials cover the bedrock. Elevation ranges from 1,310 to 2,950 ft (400 to 900 m). This Section is within Fenneman and Johnson's Great Plains geomorphic physical division.
Lithology (rock types) and Stratigraphy (rock layer types)
Most of the Section is Cretaceous marine shale, with local Tertiary (2-63 mya) sandstones and claystones in the extreme south.
Soil Taxa (groups)
Mesic (avg. 8-15°C) temperature and ustic (seasonally moist) moisture regimes occur. Soils include Mollisols, including Agriborolls and Haplustolls.
Potential Natural Vegetation
Kuchler mapped potential vegetation as wheatgrassneedlegrass prairie and wheatgrass-bluestem-needlegrass prairie and wheatgrassbluestem- needlegrass prairie with northern flood plain forests along the Missouri River lowlands. Other communities consist of mixed and natural prairie.
Fauna (animals)
Bison are historically associated with this Section, and black-footed ferrets are former inhabitants. White-tailed deer and a smaller population of mule deer are current herbivores. Small herbivores include the jackrabbit and prairie dog. Bobcat, red fox, and swift fox are present. Prairie potholes are important habitat for many species of migrating waterfowl. Horned lark, bobwhite, and greater prairie chicken are year-round residents. Summer residents include burrowing owl and belted kingfisher in riparian (streamside) zones. Dark-eyed junco and pine siskin are winter residents. Typical herpetofauna include the Great Plains toad, snapping turtle, painted turtle, and prairie rattlesnake. Black crappie and catfish are common fish species.
Climate
Precipitation averages 15 to 24 in (370 to 600 mm). Temperature averages 45 to 50°F (7 to 10°C). The growing season lasts 130 to 160 days.
Surface Water Characteristics
The Missouri, Niobrara, and White Rivers flow through here. There is a limited supply of ground water available. Shallow water developments exist, such as dug ponds and small reservoirs. Some deep artesian wells exist. Reservoirs occur on the Missouri river.
Disturbance Regimes
Fire, insects, and disease are the primary natural disturbances.
Land Use
Most of the area is in farms or ranches, with limited urban expansion. About 50 percent of the area is in dry crops. Grazing is common, especially on the Dakota- Nebraska Tableland. Irrigation occurs along the Missouri River.
Cultural Ecology
Reserved.

Data Source: United States Department of Agriculture, Forest Service.
Compiled by Rocky Mountain Region.

SECTION M334A
BLACK HILLS
Section M334A 
Geomorphology (landforms)
Slopes range from moderate on some of the high plateaus to very steep along drainage ways and on peaks and ridges. Narrow valleys are mostly gently sloping to strongly sloping. Elevation ranges from 2,950 to 7,220 ft. (900 to 2,200 m). This Section is within Fenneman and Johnson's Great Plains geomorphic physical division.
Lithology (rock types) and Stratigraphy (rock layer types)
The central part of the Section is Precambrian granite and metamorphosed sedimentary and volcanic rocks. The periphery of the North Dakota area of the Section is Paleozoic carbonates and shales. Most of the Wyoming part of the Section is Cretaceous sandstones, siltstones, shales, and Tertiary (2-63 mya) intrusive igneous rocks.
Soil Taxa (groups)
There are mesic (avg. 8-15°C), frigid (avg. <8°C), and cryic (0°-8°C) temperature regimes. Soils include Alfisols, Inceptisols, and Entisols, including Orthents and Boralfs.
Potential Natural Vegetation
Kuchler classified vegetation as dominates open to dense forest vegetation. Black Hills ponderosa pine forest.
Fauna (animals)
Typical large mammals of this Section are mule deer, white-tailed deer, elk, and mountain lion. Smaller common mammals are jackrabbits, red foxes, swift foxes, porcupines, and bushy-tailed wood rats. Year-round forest dwelling bird species include the pygmy nuthatch, red-breasted nuthatch, black-capped chickadee, and Cooper's hawk. Summer residents include sharp-shinned hawk, belted kingfisher, chipping sparrow, and swallow. Representative herpetofauna are the prairie rattlesnake, wandering garter snake, snapping turtle, spiney softshell turtle, boreal chorus frog, and Great Plains toad.
Climate
Precipitation ranges from 15 to 26 in (370 to 650 mm). Temperature averages 37 to 48°F (3 to 9°C). The growing season 80 to 140 days.
Surface Water Characteristics
Perennial streams, springs, and shallow wells are present. Cold Brook Reservoir and Pactolo Reservior are sizable man-made reservoirs in this area. The Belle Fourche and Laramie Rivers, and the South Fork of the Powder River flow through here.
Disturbance Regimes
Fire, insects, and disease are principal natural disturbances.
Land Use
Most of this area is national forest land. A small amount of acreage is in small farms, and ranches. Timber harvest, grazing, mining, and recreation are uses of this Section.
Cultural Ecology
Reserved.

Data Source: United States Department of Agriculture, Forest Service.
Compiled by Rocky Mountain Region.

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