biologically effective management of grazinglands · biologically effective management of...

BIOLOGICALLY

EFFECTIVE

MANAGEMENT OF

GRAZINGLANDS4th Edition

North Dakota State UniversityDickinson Research Extension Center

2014 4015b

North Dakota State University 2014Dickinson Research Extension CenterRangeland Research Outreach Program DREC 14-4015b

Biologically Effective Management of Grazinglands

4th Edition

Llewellyn L. Manske PhDResearch Professor of Range Science

Project AssistantSheri A. Schneider


1041 State AvenueDickinson, North Dakota 58601

Tel. (701) 456-1118Fax. (701) 456-1199

North Dakota State University is an equal opportunity institution.

CONTENTS

Rangelands of the Northern Plains

Northern Plains Rangelands.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Physiography, Soil, and Native Vegetation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Seasonal Weather Patterns.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Soil Formation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Prehistorical Conditions of Rangelands.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Problems Inherent in Grasslands. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

Effects of Environmental Factors

Climatic Factors Affect Plant Growth. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Plant Water Stress Frequency and Periodicity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Grazing Starting Dates. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

Grass Growth in Height. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

Effects of Fall Grazing on Height. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

Proactive Management of Pest Grasshopper Habitat.. . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

Effects of Partial Defoliation

Grazing Effects on Rangeland Vegetation.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

Grazing Effects on Tillering and Rhizosphere Volume.. . . . . . . . . . . . . . . . . . . . . . . . . . 87

Tillering Responses to Partial Defoliation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

Tiller Initiation and Tiller Density. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135

Forage Tiller Response to Partial Defoliation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148

Effects of Grazing Management Treatments

Cow and Calf Performance on Grazing Strategies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174

Cow and Calf Performance on Fall Pastures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202

Preface

Biologically effective management of grazinglands places priority with the livingcomponents of ecosystems for the purpose of meeting the biological requirements of grasslandplants and soil organisms contrary to traditional grazing practices that place priority on the use ofgrasslands as a source of forage for livestock. The biologically effective twice-over rotationgrazing management strategy with complementary domesticated grass spring and fall pasturescoordinates partial defoliation by grazing with grass phenological growth stages for the beneficialmanipulation of grassland ecosystem biogeochemical processes. Grass plants developeddefoliation resistance mechanisms during the period of coevolution with graminivores that helpgrass tillers withstand and recover from partial defoliation by grazing. These essential biologicalmechanisms are the scientific basis for biologically effective management strategies; thesemechanisms are triggered by partial defoliation by grazing during phenological growth betweenthe three and a half new leaf stage and the flower (anthesis) stage, and these mechanisms arefully activated when 100 lbs/ac soil mineral nitrogen is available from the rhizosphere organisms. The three main mechanisms are: compensatory internal physiological processes within remainingleaf and shoot tissue that increase growth rates of replacement leaves; internal vegetativereproduction from axillary buds that increases secondary tiller density and herbage biomass; andexternal rhizosphere organism symbiotic activity that increases available mineral nitrogenconversion from soil organic nitrogen; thereby enhancing productivity of grassland ecosystems.

The basic concepts for biologically effective management of grazinglands weredeveloped from research projects conducted in the Northern Plains, however, the resultinggrazingland management strategies and recommendations are applicable to all grazinglandregions where perennial grass plants reproduce vegetatively and are exposed to frozen soil duringthe winter season.

RANGELANDS

OF THE

NORTHERN PLAINS

Northern Plains Rangelands

Llewellyn L. Manske PhDReport DREC 03-17b Range Scientist


Northern Plains rangelands are a valuablerenewable natural resource that provides a multitudeof benefits. Much of the region’s economic base isdependent on rangelands, which are the principal landtype for the area’s recreation, wildlife, and tourismindustries and provide the majority of the forage basefor the livestock industry. The use of rangelands asgrazinglands for domesticated livestock is the premierexample of high-value-added sustainable agriculturewith low energy input. The vegetation is selfperpetuating, and the animals harvest their ownforage. Grazing livestock on rangelands convertsperennial vegetation that cannot be directly consumedby humans into a high-quality food and providesbeneficial secondary products such as fibers,medicines, cosmetics, oils, glues, and basecompounds. The vegetation on rangelands provideshabitat for wildlife and scarce plants and animals andstabilizes the soil, protecting it from wind and watererosion. Through photosynthesis, the plants reducethe levels of carbon dioxide in the air and releaseclean oxygen into the atmosphere. Rangelandscollect, filter, and store water in aquifers and smallbasins (pot holes), then slowly release it into streamsand rivers by processes that reduce the damagingeffects of fast runoff and floods. Rangelands provideclean water for plants, animals, and humans. Theopen spaces of rangelands are aesthetically appealingand offer opportunities for recreation and sightseeing.

Properly managed, rangelands can be maintained at high levels of production in perpetuity. Rangelands are managed with ecological principles,unlike cropland, which is managed with agronomicprinciples. Proper management of rangelandsrequires an understanding of the effectsenvironmental forces have on plant growth and of thecomplex processes within the plants and ecosystems. Ecological and biological requirements of grassplants can be met by properly timed defoliation bygrazing. Rangeland plants have become biologicallyadapted to grazing. The adaptations are expressedthrough resistance mechanisms plants have developedin response to the evolutionary selective forces ofdefoliation. To maintain adequate activity of thesebiological processes, healthy range plants requireannual defoliation by grazing. Management that isfocused on a single use and that does not includeannual defoliation at the appropriate growth stagescannot sustain a healthy ecosystem over time. Management that places the biological requirementsof the plants as the highest priority and facilitates theoperation of ecosystem functions at potential levelswill sustain healthy, productive rangelands that willremain a valuable renewable natural resource,providing forage for livestock, habitat for wildlife andplants, clean air, clean water, open spaces forrecreation and sightseeing, and food, fiber, andenergy for people. The greatest attribute ofrangelands is that when managed properly, they canprovide all of these valuable benefits at the sametime.

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Physiography, Soil, and Native Vegetation of the Northern Plains

Llewellyn L. Manske PhDReport DREC 08-3048 Range Scientist


Land resources of the Northern Plains arethe source of new wealth generated by livestockagriculture. The land natural resources consist ofcomplex ecosystems with several trophic layers ofliving organisms that have individual biologicalrequirements and nonliving (abiotic) components thathave changeable characteristics. Biologicallyeffective management benefits all living andnonliving ecosystem components by meeting thebiological requirements of the plants and soilorganisms and by fostering the characteristics of thesoil resulting in continuation of ecosystem productionat potential sustainable levels. The potentialproductivity of healthy ecosystems are effected by thesame environmental and biological factors that causechanges in physiographic landform characteristics,soil characteristics, and native vegetation types. Thecharacteristics and relationships of the physiography,soil, and native vegetation of the Northern Plains aredescribed in this report.

Physiographic Regions

The Northern Plains are part of the NorthAmerican Interior Plains that extend from the foot ofthe Rocky Mountains eastward to the CanadianShield and Appalachian Provinces and extend fromthe Athabasca River on the Alberta Plateau southwardto the Gulf Coastal Plains (Fenneman 1931, 1946;Hunt 1974; Goodin and Northington 1985). TheInterior Plains are divided east and west into theGreat Plains and the Central Lowland PhysiographicProvinces (Fenneman 1931, 1946). The NorthernPlains are separated from the Southern Plains by theNorth Platte-Platte-Missouri River Valleys (Raisz1957). The portions of the Great Plains and CentralLowland Provinces that exist in the Northern Plainsare separated in North and South Dakota andSaskatchewan by an eroded east facing escarpment atthe eastern extent of the Tertiary sedimentary depositsof material eroded from the Rocky Mountains thatform a fluvial plain overlaying the Cretaceousbedrock (Hunt 1974). The surface landform featurethat shows the location of this boundary is the eastescarpment of the Missouri Coteau (Finneman 1931). In eastern Nebraska, the separation of the GreatPlains and Central Lowland Provinces is the western

limit of older pre-Wisconsin glacial drift which has amantle of loess (wind deposited silt) (Fenneman1931).

Great Plains Province

The Missouri Plateau Section and thenorthern portion of the High Plains Section of theGreat Plains Province are separated in southern andeastern South Dakota by the north facing Pine RidgeEscarpment and the southern bluffs of the MissouriRiver Valley (Fenneman 1931). The portion of theHigh Plains that extends into the Northern Plains isdivided into Pine Ridge, Sand Hills region, LoessPlain, and Goshen Hole Lowland landscape features. The Missouri Plateau, including the Alberta Plain, isdivided into three sections: Glaciated, Unglaciated,and Black Hills, along with smaller domed mountains(Fenneman 1931, 1946; Hunt 1974).

Missouri Plateau Section

The Unglaciated section of the MissouriPlateau is north of the Pine Ridge Escarpment inSouth Dakota, south of the Missouri River inMontana, and west of the Missouri River in Northand South Dakota (Fenneman 1931, 1946; Hunt1974). Portions of this section were undoubtedlyglaciated during glacial advances earlier thanWisconsin Age. However, there is little geologicevidence of older glaciation. The importantdistinction between the Unglaciated and Glaciatedsections is the type and age of parent material fromwhich the soil develops. The landscape surface of theUnglaciated section is highly eroded fluvialsedimentary deposits of material removed from theuplifted Rocky Mountains. Most of the depositionoccurred from slow meandering streams during theLaramide Orogeny, that formed the mountains, andduring the 20 to 30 million years of the lateCretaceous and early Tertiary Periods following theuplift. Intense widespread erosion of these sedimentsoccurred from about 5 to 3 million years ago duringthe late Pliocene Epoch (Bluemle 2000). Theextensive erosion during this period removed about500 to 1000 feet of sediments (Fenneman 1931). These fluvial Tertiary sediments had great differences

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in hardness and durability. The soft andunconsolidated material was easily removed and theharder coherent material had greater resistance toweathering and to erosional forces of wind andrunning water. Differential erosion formed alandscape with well developed integrated drainagesystems of broad mature valleys and gently rollinguplands containing widely spaced large hills andbuttes with erosion resistant caps raising 500 to 650feet above the plain (Bluemle 2000).

In addition to the high relief from erosionresistant capped remnant hills and buttes on thelandscape, several isolated domed mountain groupswith 1500 to 2000 foot rise formed on the MissouriPlateau. These laccolithic mountains developed fromthe upward push of rising igneous intrusions (moltenmagma) that did not penetrate through to the surfacebut caused a diastrophic bulge with a single fold inthe uplifted sediments. Differential erosion has sinceexposed the underlying tilted strata (Froiland andWeedon 1990) and sometimes the intrusive rock(Robinson and Davis 1995). Along with the largedome uplifted Black Hills in South Dakota andWyoming, which is treated as a separate section, theSweetgrass Hills, and the Highwood, Bearpaw, LittleRocky, Moccasin, Judith, and Big Snowy mountainsin Montana are smaller domed mountain groups(Fenneman 1931, Hunt 1974). The Highwood andBearpaw domed mountains include extinct volcanoes(Fenneman 1931).

Drainage of the Missouri Plateau during thehighly erosional period of the Pliocene (5 to 3 millionyears ago) was primarily north and northeast towardsthe Hudson Bay area. The climate became coolerabout 2.6 million years ago and, about 700,000 yearsago, the climate was cold enough to producecontinental glaciers (Bluemle 2000). Early glacialadvances blocked the northward paths of the riversdraining the Unglaciated section and diverted waterflow into steeper southern routes. The increasedgradient of several rivers caused drastic downcuttingthrough areas of poorly consolidated, soft, finetextured sediments resulting in formation of badlandregions (Fenneman 1931).

The Glaciated section of the MissouriPlateau is north of the Missouri River in Montana,including the Alberta Plain between the foot of theRocky Mountains and the Missouri CoteauEscarpment in Canada, and extends southwardbetween the Missouri River and the east escarpmentof the Missouri Coteau in North and South Dakota(Fenneman 1931, Hunt 1974). The section has amantle of glacial and glacier related drift deposited

between 70,000 and 10,000 years ago during theWisconsin Age. The Missouri Coteau has 500 to 600feet of terminal moraine deposits. The thick depositsof unsorted glacial sediment are a result of the largequantities of additional rock and sediments picked upfrom beneath the ice and forced upward into theglacier along shear planes that were generated bygreat internal stress (Bluemle 2000) when theadvances of numerous glaciers were forced toprogress up the steep escarpment of Tertiarydeposited fluvial sediments. Large masses ofstagnant ice remained buried under debris on theCoteau area for about 3000 years following thenorthern retreat of the last continental glacier. As thestagnant blocks of ice melted, the overlying materialslumped down forming depressions (Bluemle 2000). The resulting topography is an irregular surface withclosely spaced hills of 100 to 150 feet in heightenclosing basins, or kettles, that usually containponds (Fenneman 1931). The drainage is local andcompletely unintegrated with only a few shortstreams.

The glaciated areas north of the MissouriRiver and on the Alberta Plain have a mantle of tilland outwash. The topography is generally rough. The plain is dissected by broad river valleys that haveentrenched 200 to 400 feet. The upland areas containseveral erosional remnants that have local relief ofabout 1000 to 2000 feet. The Cypress Hills inSaskatchewan are the highest and have a height tallenough that they were not overriden by glacial ice. The gravel capped Cypress Hills were part of anancient valley where a thick layer of rock from theRocky Mountains was deposited by rivers. Thisheavy gravel layer protected the surface during thesevere erosional period of the late Pliocene, whilesurrounding higher areas were eroded down to levelsbelow the gravel layer forming an invertedtopography (Fenneman 1931).

High Plains Section

A small portion of the High Plains Sectionof the Great Plains Province exists between the PineRidge Escarpment in South Dakota and the NorthPlatte-Platte River Valley in Nebraska and is includedwithin the Northern Plains (Fenneman 1931, 1946;Hunt 1974). Contrary to the erosional surface of theUnglaciated section of the Missouri Plateau north ofPine Ridge, the northern portion of the High Plains isprimarily a depositional surface. The uplands of PineRidge north of the Niabrara River are exposedTertiary fluvial sediments of the Arikaree Formationdeposited during the Miocene and have a gentlyrolling to nearly flat topography. The Goshen Hole

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Lowland located in western Nebraska south of thewest end of Pine Ridge is a landform about 50 mileswide and 150 miles long where the North Platte Riverremoved about 700 feet of fine textured clay Tertiarysediments during a period when the river had arelatively steep gradient. The Sand Hills region inNebraska is located south of the Niobrara River andnorth of the Platte River. Wind deposited sandcovers the Tertiary sediments of the region and formsa sand dune topography. Small areas have activedune movement, however, most of the region hasbeen stabilized by grassland vegetation. Some of thesand hills are several hundred feet high. Lakes,ponds, or wetlands form in the depressions. TheLoess Plain in north central Nebraska is located eastof the Sand Hills region. Wind deposited silt (loess)about 100 feet thick covers the Tertiary sediments ofthe area and forms a gently rolling topography(Fenneman 1931).

Central Lowland Province

The Small Lakes Section and the DissectedTill Plains Section of the Central Lowland Provinceare separated by the age of the glacial till and thedegree of development of integrated drainagesystems. The Small Lakes Section is located in thenorthwestern part of the Central Lowland Provinceand extends eastward from the escarpment of theMissouri Coteau to the Great Lakes Section (Hunt1974). However, for this report, the Small LakesSection description extends eastward only to thetransition between the Tall Grass Prairie and the OakForest in western Minnesota.

Small Lakes Section

The Small Lakes Section has a mantle ofWisconsin Age glacial till and glacial lake deposits. The Saskatchewan Plain between theMissouri Coteau Escarpment and the ManitobaEscarpment in Canada and the Glaciated Plains (DriftPrairie) east of the Missouri Coteau in North andSouth Dakota extending into western Minnesota arean undulating plain of ground moraine forming aknob and kettle topography with low to moderaterelief (Hunt 1974). Water collects in the lowerportions of the landscape forming lakes and ponds ormarshes with the size decreasing westward with thedecrease in annual precipitation (Hunt 1974). TheSmall Lakes Section does have a few river systems,however, these rivers are still at the early stages ofdeveloping complex integrated drainage systems. Thick glacial deposits forming a hummocky collapsedtopography (Bluemle 2000) cover Moose Mountainin Saskatchewan and the Turtle Mountains in

Manitoba and North Dakota as a result of shear stressplanes developing in the ice as the glaciers advancedover preexisting high relief erosional remnant hills.

Glacial Lake Plains of relatively flat finesediments and reworked till were formed by glaciallakes that developed when meltwater collected inlandscape depressions, along the edge of recedingglaciers, or as a result from ice damming drainageroutes (Ojakangas and Matsch 1982, Bluemle 2000). Lakes Agassiz, Aitkin, Dakota, Duluth,Minnewaukan, Regina, Souris, and Upham weremajor glacial lakes that existed for periods sometimebetween 12,200 and 7,500 years ago. Lake Agassizwas, by far, the largest of the glacial lakes and itswestern edge is defined by the Manitoba-PembinaEscarpment. This escarpment was formed during thehighly erosional period of the Pliocene when artesianground water from the Cretaceous Dakota sandstoneformation and overland water from the Grand,Cheyenne, and White Rivers flowed into the ancestralRed River, cut through the relatively soft Cretaceoussediments down to the west sloping Precambrianigneous rock of the Canadian Shield, andprogressively shifted the erosional face westward(Bluemle 2000). These erosional surfaces were latercovered with thick layers of glacial till and lakesediments during the Pleistocene glaciation. Theexceptionally flat surface of Glacial Lake Agassizsediments east of the Manitoba-Pembina Escarpmentform the Manitoba Plain in Canada and the Red RiverValley Plain in eastern North Dakota and westernMinnesota.

Dissected Till Plains Section

The Dissected Till Plains Section was notglaciated during the Wisconsin Age. The glacial tillof this section is from older glacial advances. Theold dissected till deposits extend westward from theMississippi River across southern Iowa and northernMissouri and narrows northward into southwesternMinnesota and southeastern South Dakota (Fenneman1946, Raisz 1957). The western limit of the oldglacial till occurs in eastern Nebraska. The drainagesystems on older till have had longer to develop acomplex integrated pattern with closely spaced deepvalleys and rounded uplands. There are few lakesand ponds in this section and a younger mantle ofabout 30 feet of wind blown loess (silt) covers theregion (Hunt 1974).

Soil Characteristics

Soil development is effected by climate,parent material, topography, living organisms, and

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time (Brady 1974). The main climatic factors thataffect soil development are temperature andprecipitation. Climate determines the type and rate ofweathering that occurs. The rates of biogeochemicalprocesses in soil are effected by soil temperature andsoil moisture. Climate determines the type of nativevegetation and the quantity of biomass production. There is a relationship between the type of nativevegetation and the kind of soil that develops. Increases in soil moisture, increase the biomassproduction and tend to increase organic content ofsoils. Increases in soil temperature, increase the rateof decomposition and tend to decrease organiccontent of soils (Brady 1974).

The Northern Plains has a continentalclimate with cold winters and hot summers. Mean airtemperatures increase from north to south changingfrom about 35E - 40E F (1.7E - 4.4E C) in the north toabout 48E - 51E F (8.9E - 10.6E C) in the south. Mostof the precipitation occurs during the early portion ofthe growing season. Total annual precipitationfluctuates greatly from year to year. Periods of waterdeficiency during the growing season occur morefrequently than growing seasons without deficiencies. Drought conditions are common. Mean annualprecipitation increases from west to east and increasesfrom north to south. In the northern portion,precipitation ranges from about 12 inches (304.8 mm)in the west to about 24 inches (609.6 mm) in the east. In the southern portion, precipitation ranges fromabout 14 inches (355.6 mm) in the west to about 32inches (812.8 mm) in the east.

Evapotranspiration affects the quantity ofmoisture in the soil and the duration infiltrated waterremains available for plant growth. The potentialevapotranspiration for most of the Northern Plains isgreater than annual precipitation. Potentialevapotranspiration demand increases from north tosouth, and increases from east to west. Along theeastern edge of the Northern Plains, the precipitationis greater than potential evapotranspiration duringmost years. The region also has several local areaswhere the combination of stored soil water,precipitation, plus water runin is greater thanevapotranspiration. Subirrigated soils where therooting zone is moist for most of the growing seasonwould be comparable to conditions with greaterprecipitation than evapotranspiration.

The properties of the parent material thataffect soil development include texture and structure,and chemical and mineral composition. The textureand structure of parent material varies from fine tocoarse and is related to the type of source material

and the degree of weathering. The texture of theparent material determines the texture of the soil andthe relative content of clay, silt, sand, and gravel. The texture of the soil controls the downwardmovement of water. The chemical and mineralcomposition of the parent material strongly influencesthe growth of the native vegetation and determinesthe effectiveness of the weathering forces. Parentmaterial influences the quantity and type of clayminerals that develop (Brady 1974). The parentmaterial on the Northern Plains is eroded Tertiaryfluvial sedimentary deposits, unsorted glacial till,sorted glacier related deposits of outwash and lakesediments, and wind deposited sand and silt.

Landform topography modifies soildevelopment by influencing the quantity ofprecipitation absorbed and retained in the soil,determines aspect to solar radiation, and influencesthe rate of soil removal by erosion. Water, organicmatter, mineral matter, and soluble salts move downslope, whether over the surface or internally. Thesteeper the gradient, the greater the movement. Soiltemperature changes with slope aspect. Increases insoil temperature, increase evapotranspiration anddecomposition rates. Upper slope soils tend to havelower soil moisture, less organic matter, and thinnerhorizon development than lower slope soils fromsimilar parent material (Brady 1974).

Living organisms (including plants, animals,and soil microorganisms) affect soil development byinfluencing organic matter accumulation, profilemixing, nutrient cycling, and structural stability. Thesource of soil organic matter is the dead tissue andwaste from organisms, decomposition is performedby soil organisms, nutrient cycles are complexprocesses involving living organisms, burrowingcritters mix soil material, and soil aggregation is aresult of soil organism secretions (Brady 1974).

Time is required for soils to develop andmature. However, soils do not all develop at thesame rate. Conditions that increase soil developmentare warm humid climate, parent material highlypermeable by water, unconsolidated material, lowlime content, depression or level topography, gooddrainage, and forest vegetation. Conditions thatretard soil development are cold dry climate, parentmaterial not permeable by water, consolidatedmaterial, high lime content, steeply slopingtopography, poor drainage, and grassland vegetation(Brady 1974). Some very old soils in the NorthernPlains show little or no evidence of horizondevelopment because they exist in dry regions, onsteep, actively eroding slopes where the rate of soil

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removal is as great or greater than the rate of soildevelopment.

The soils that are developing in the NorthernPlains fit into the order classification descriptions ofMollisols, Aridisols, and Entisols.

Mollisols are mineral soils that developunder grassland vegetation with a thick mollicepipedon that is “soft”, high in organic matter, anddark colored. The limited leaching results in a highbase saturation with a concentration of positivelycharged exchangeable cations other than hydrogen. Most Mollisols in the Northern Plains have, or aredeveloping, an argillic (clay) layer in an uppersubhorizon and have an accumulation of calciumcarbonate (lime) at some level of the profile (SoilSurvey Staff 1975).

Aridisols are mineral soils that develop inaridic (dry) or torric (hot and dry) climates with a thinochic epipedon that is low in organic matter and lightcolored. Soil water is not available to plants for longperiods during the growing season. In the NorthernPlains, the Aridisols have an argillic (clay) layer in anupper subhorizon and as a result of limited leaching,soluble salts, like calcium carbonate, accumulate in azone that marks the average depth of moisturepenetration (Soil Survey Staff 1975).

Entisols are mineral soils that show little orno evidence of horizon development and have a thinochic epipedon that is low in organic matter and lightcolored. In the Northern Plains, considerableretardation of soil development produces Entisolswhere dry and/or salty medium to fine texturedsediments with sparse grass or shrub vegetation arelocated on gentle to steep, actively eroding slopeswith the rate of soil removal as great as the rate ofsoil development, or where coarse textured, wellsorted, wind deposited sand with low water holdingcapacity and thin grass vegetation become dry and areeasily moved by wind (Soil Survey Staff 1975).

Classification of soils into principalsuborders is based on differences caused by climateand associated native vegetation. The biologicalprocesses in soil are effected by soil temperature andsoil moisture. The different climatic characteristicsimportant in soil development are separated intospecific soil temperature regimes and soil moistureregimes.

The Northern Plains has two soiltemperature regimes based on mean annual soiltemperature. The mean annual soil temperature is

considered to be the mean annual air temperature plus1.8E F (1E C ) (Soil Survey Staff 1975). The Frigidsoil temperature regime has mean annual soiltemperatures of less than 47E F (8E C). The Mesicsoil temperature regime has mean annual soiltemperatures higher than 47E F (8E C) and lower than59E F (15E C) (Soil Survey Staff 1975). Theseparation between the Frigid and Mesic soiltemperature regimes occurs along a wide irregularbelt that extends eastward from central Wyomingalong its north border with Montana and continues tonorth central South Dakota just south of its northborder with North Dakota, then extends at asoutheasterly diagonal to about the center of SouthDakota’s east border with Minnesota, and thenextends at a northeasterly angle to the boundary of theOak Forest.

Soil moisture regimes are based on the soilmoisture conditions in the soil. The Northern Plainshas four north-south zones of soil moisture regimesthat increase in soil moisture from west to east. Thesoils in the Aridic and Torric soil moisture regime,typically of arid climates, are dry in all parts for morethan half the time and the soils are never moist for aslong as 90 days during the growing season (SoilSurvey Staff 1975). The soils in the Ustic soilmoisture regime, typically of semi arid climates, aredry in some or all parts for 90 or more days in mostyears, but not dry in all parts for more than half thetime, and are not dry for as long as 45 days during the4 months that follow the summer solstice in 6 or moreyears out of 10 years (Soil Survey Staff 1975). Thesoils in the Udic soil moisture regime, typically of subhumid climates, are not dry for as long as 90 days. During the summer, the amount of stored moistureplus rainfall is approximately equal to or exceeds theamount of evapotranspiration (Soil Survey Staff1975). The soils in the Perudic soil moisture regime,typically of humid climates, are rarely dry. Duringthe summer, the precipitation is greater than theevapotranspiration (Soil Survey Staff 1975).

The combination of four soil moistureregimes (Aridic, Ustic, Udic, and Perudic) and twosoil temperature regimes (Frigid and Mesic) results ineight distinct soil moisture-temperature regimes in theNorthern Plains. The soils in the Aridic-Frigid soilmoisture-temperature regime are primarily AridicBorolls (arid cool Mollisols) and Torriorthents (hotdry recently eroded medium to fine textured Entisols)and support vegetation of short grasses with somemid grasses. The soils in the Ustic-Frigid soilmoisture-temperature regime are primarily TypicBorolls (semi arid cool Mollisols) and supportvegetation of mid and short grasses. The soils in the

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Udic-Frigid soil moisture-temperature regime areprimarily Udic Borolls (sub humid cool Mollisols)and support vegetation of mid grasses with some tallgrasses. The soils in the Perudic-Frigid soil moisture-temperature regime are primarily Aquolls (humidcool Mollisols that are saturated and absent of oxygenat times for unknown lengths) and support vegetationof tall grasses. The soils in the Aridic-Mesic soilmoisture-temperature regime are primarily Argids(arid warm Aridisols with thin horizons, dry for longperiods, and have a clay layer) and Aridic Ustolls(arid warm Mollisols) and support vegetation of shortgrasses. The soils in the Ustic-Mesic soil moisture-temperature regime are primarily Ustipsamments(semi arid warm Entisols that are well sorted winddeposited sands) and Typic Ustolls (semi arid warmMollisols) and support vegetation of mid and shortgrasses with lower topographic slopes supporting tallgrasses. The soils in the Udic-Mesic soil moisture-temperature regime are primarily Udic Ustolls (subhumid warm Mollisols) and support vegetation of midgrasses and tall grasses. The soils in the Perudic-Mesic soil moisture-temperature regime are primarilyUdolls (humid warm Mollisols that do not have acalcium carbonate layer) and support vegetation oftall grasses.

Native Vegetation Types

Development of plant communities andvegetation types is effected by the climaticcharacteristics of temperature, precipitation, andevapotranspiration demand; the soil characteristics oftexture, structure, and chemical and mineralcomposition; and the landform topographiccharacteristics of slope, aspect, and elevation. Vegetation of the Northern Plains separates into 10grassland vegetation types and 7 grassland withwoodland or forest vegetation types. The vegetationof the Northern Plains map (figure 1) developed byDr. W.C. Whitman (Barker and Whitman 1989) is acompilation of information from several sourcessupplementary to the basic map of potential naturalvegetation by Kuchler (1964). Modifications tovegetation type designations, distributions, andboundaries were conflated into the base map fromstate vegetation maps for Montana (Ross and Hunter1976, Hacker and Sparks 1977), Nebraska (Kaul1975, Bose 1977), North Dakota (Shaver 1977),South Dakota (Baumberger 1977), and Wyoming(Shrader 1977). Vegetation type designations anddistributions from scientific papers were added forCanada (Clarke, Campbell, and Campbell 1942;Moss and Campbell 1947; Coupland and Brayshaw1953; Coupland 1950, 1961). A new concept of aplains rough fescue mixture along a portion of the

northern border of North Dakota was introduced tothe map details by Whitman and Barker (1989).

No living plant species are known to haveoriginated in the Northern Plains. All plant speciesconsidered to be native to the Northern Plainsoriginated and developed in other regions andsometime later migrated into the Northern Plains. The plant communities and vegetation types,however, are relatively young and began developmentin place about 5,000 years ago when the currentclimate with cycles of wet and dry periods began. Nomenclature of plants in the vegetation types of theNorthern Plains followed Flora of the Great Plains(1986) in Barker and Whitman (1989) and, inaddition, nomenclature of grass plants follows Floraof North America (2003, 2007) in this report.

Tall Grass Prairie

The Tall Grass Prairie, Bluestem-Switchgrass-Indiangrass Type, exists on the easternmargin of the Northern Plains Grasslands and extendsfrom southern Manitoba through eastern North andSouth Dakota and western Minnesota southward intonorthwestern Iowa and northeastern Nebraska to thePlatte River. The physiography of the region consistsof the Manitoba Plain and the Red River Valley Plainof the Small Lakes Section and extends into theDissected Till Plains Section of the Central LowlandProvince. The climate is humid withevapotranspiration lower than precipitation. The soilmoisture regime is Perudic and the soil temperatureregime is Frigid in the north and Mesic in the south. The soils are primarily Aquolls in the north andUdolls in the south. The major grasses of theBluestem-Switchgrass-Indiangrass Type of the TallGrass Prairie (table 1) are big bluestem,porcupinegrass, switchgrass, prairie dropseed, andindiangrass. Cool-season grass species increasetowards the northern portions and warm-season grassspecies increase towards the southern portions. Bigbluestem occupies the lower slopes and subirrigatedsoils in the north and increases in dominance in thesouth. Prominent forbs are prairie clover, tall blazingstar, large beardtongue, stiff sunflower, scurf pea,white prairie aster, white sage, prairie goldenrods,and violets. Major shrubs are leadplant, whitespiraea, wild roses, western snowberry, and willows. Most of this vegetation type has been converted tocropland, and only fragments of tall grass prairievegetation remain. Plant communities with tall grassspecies exist in several other vegetation types wherenear equivalent environmental conditions developfrom combinations of precipitation, stored soil water,

7

and water runin that are greater thanevapotranspiration.

Transition Mixed Grass Prairie

The Transition Mixed Grass Prairie,Wheatgrass-Bluestem-Needlegrass Type (figure 1),exists between the Tall Grass Prairie on the east andthe Mixed Grass Prairie on the west and extends fromeast central Saskatchewan and southwesternManitoba through east central North and SouthDakota and east central Nebraska to the Platte River. The physiography of the region consists of theSaskatchewan Plain and the Glaciated Plains (DriftPrairie) of the Small Lakes Section of the CentralLowland Province and extends into the easternportion of the High Plains Section of the Great PlainsProvince. The climate is sub humid withevapotranspiration greater than precipitation overmost of the area except for subirrigated soils andtopographic slope positions with water runin. Thesoil moisture regime is Udic and the soil temperatureregime is Frigid in the north and Mesic in the south. The soils are primarily Udic Borolls in the north andUdic Ustolls in the south. The major grasses of theWheatgrass-Bluestem-Needlegrass Type of theTransition Mixed Grass Prairie (table 2) are westernwheatgrass, thickspike (northern) wheatgrass, littlebluestem, porcupinegrass, needle and thread, andgreen needlegrass. Cool-season grass speciesincrease towards the northern portions and warm-season grass species increase towards the southernportions. The needlegrasses and thickspikewheatgrass increase in the north. Little bluestemincreases in the south. Prominent forbs are whiteprairie aster, scurf peas, prairie coneflower, purpleconeflower, milkvetches, dotted blazing star, whitesage, soft goldenrod, curlycup gumweed, hairygolden aster, and stiff sunflower. Major shrubs arewild roses, western snowberry, silverberry, leadplant,white spiraea, and willows. Plant communitieschange with topographic position. Wetlandcommunities develop in nearly concentric ringsaround depressions. The salt-affected “pot holes”support saline plant communities. Wet meadowcommunities develop on subirrigated soils. Uplandcommunities develop on well drained soils and xericcommunities develop on shallow soils. Kentuckybluegrass and western snowberry communities havegreatly increased in this region as a result of highstocking rates and too early of grazing starting dates.

Mixed Grass Prairie

The Mixed Grass Prairie has a high midgrass component with some short grasses and some

tall grasses present and is separated into threevegetation types based on differences resulting fromsoil texture and soil temperature regime.

The Mixed Grass Prairie, Wheatgrass-Needlegrass Type (figure 1), exists on semi arid coolsoils between the Transition Mixed Grass Prairie onthe east and the Short Grass Prairie on the west andextends from mid Saskatchewan through westernNorth Dakota and eastern Montana to north centraland northwestern South Dakota. The physiography ofthe region consists of the eastern portions of theGlaciated and Unglaciated sections of the MissouriPlateau Section, including the Alberta Plain, of theGreat Plains Province. The climate is semi arid withevapotranspiration greater than precipitation. Thesoil moisture regime is Ustic and the soil temperatureregime is Frigid. The soils are primarily TypicBorolls. The major grasses of the Wheatgrass-Needlegrass Type of the Mixed Grass Prairie (table3) are western wheatgrass, needle and thread, bluegrama, prairie Junegrass, and green needlegrass. Prominent forbs are white prairie aster, scarlet gaura,scarlet globemallow, purple prairie clover, dottedblazing star, purple locoweed, fringed sage, whitesage, hairy golden aster, curlycup gumweed, Hood’sspiny phlox, prairie smoke, green sage, and prairiechickweed. Major shrubs are silver sagebrush,buffaloberry, wild roses, western snowberry, broomsnakeweed, and creeping juniper. This vegetationtype grows in soils developed from glacial till northand east of the Missouri River and grows in soilsdeveloped from Tertiary sedimentary deposits southand west of the Missouri River. Soils in theunglaciated section are developing an argillic (clay)layer and accumulating soluble salts in a subhorizonat decreasing depths from east to west.

The Mixed Grass Prairie, Wheatgrass-Grama Type (figure 1), exists on semi arid warm claysoils south of the Wheatgrass-Needlegrass Type andis in southwestern South Dakota. The physiographyof the region consists of the southeastern portion ofthe Unglaciated section of the Missouri PlateauSection of the Great Plains Province. The climate issemi arid with evapotranspiration greater thanprecipitation. The soil moisture regime is Ustic andthe soil temperature regime is Mesic. The soils areprimarily clay textured Typic Ustolls. The majorgrasses of the Wheatgrass-Grama Type of the MixedGrass Prairie (table 4) are western wheatgrass, bluegrama, and buffalograss. This vegetation type isseparated from the Wheatgrass-Needlegrass Typebecause the clay textured soils and warmer soiltemperature regime result in near removal of needle

8

and thread and in greatly increasing blue grama andbuffalograss.

The Mixed Grass Prairie, Wheatgrass Type(figure 1), exists on semi arid warm dense clay soilssouth of the Wheatgrass-Needlegrass Type and is innorthwestern South Dakota. The physiography of theregion consists of the central portion of theUnglaciated section of the Missouri Plateau Sectionof the Great Plains Province. The climate is semi aridwith evapotranspiration greater than precipitation. The soil moisture regime is Ustic and the soiltemperature regime is Mesic. The soils are primarilydense clay textured Typic Ustolls. The major grassesof the Wheatgrass Type of the Mixed Grass Prairie(table 5) are western wheatgrass, green needlegrass,and thickspike wheatgrass. This vegetation type isseparated from the Wheatgrass-Needlegrass Typebecause the dense clay textured soils and warmer soiltemperature regime result in removal of blue gramaand near removal of needle and thread.

Short Grass Prairie

The Northern Short Grass Prairie, Grama-Needlegrass-Wheatgrass Type (figure 1), exists onthe western side of the Northern Plains Grasslandsand extends from southeastern Alberta andsouthwestern Saskatchewan through central Montanaand southward into northeastern Wyoming. Thephysiography of the region consists of the westernportions of the Glaciated and Unglaciated sections ofthe Missouri Plateau Section of the Great PlainsProvince. The climate is arid with evapotranspirationgreater than precipitation. The soil moisture regimeis Aridic and the soil temperature regime is Frigid inthe north and Mesic in the south. The soils areprimarily Aridic Borolls and Torriorthents in thenorth and Argids and Aridic Ustolls in the south. Themajor grasses of the Grama-Needlegrass-WheatgrassType of the Northern Short Grass Prairie (table 6) areblue grama, needle and thread, small needlegrass,western wheatgrass, thickspike wheatgrass, greenneedlegrass, and buffalograss. Prominent forbs arefringed sage, green sage, milkvetches, Hood’s spinyphlox, curlycup gumweed, and prairie chickweed. Major shrubs are big sagebrush, silver sagebrush,rabbitbrush, broom snakeweed, plains prickly pear,greesewood, shadescale, saltbush, and winterfat. Dr.Whitman (Barker and Whitman 1989) continued theseparation of this vegetation type from theWheatgrass-Needlegrass Type because of the notableincrease in the shortgrass component and the relativedecrease of western wheatgrass and needle andthread. Cool-season grass species increase towardsthe northern portions and warm-season grass species

increase towards the southern portions. Theneedlegrasses increase in the north. Blue grama andbuffalograss increase in the south. Because of thepresence of mid cool-season grasses, the NorthernShortgrass Prairie has sometimes been combined withthe Northern Mixed Grass Prairie. However, thesetwo vegetation types are distinct and should remainseparated. The Grama-Needlegrass-Wheatgrass Typehas the appearance of a shortgrass prairie and has anarid soil moisture regime, less soil horizondevelopment, shallower soil depth to theaccumulating soluble salts and developing argillic(clay) layer, shallower rooting depth, lower soil waterholding capacity, greater evapotranspiration potential,and generally more xeric than the Wheatgrass-Needlegrass Type.

The Northern Short Grass Prairie, SaltgrassType, exists on salt affected soils distributed in localareas across the Northern Short Grass Prairie region. The major grasses of the Saltgrass Type of theNorthern Short Grass Prairie (table 7) are saltgrass,alkali cordgrass, basin wildrye, foxtail barley, littlebarley, and Nuttall’s alkali grass. Few plant speciescan tolerate the harsh environmental conditions ofsalt-affected areas. The tolerant species havemechanisms to exclude uptake of salts, orphysiologically separate and discharge the undesiredsalts.

The Southern Short Grass Prairie, Bluegrama-Buffalograss Type (figure 1), exists innorthwestern Nebraska and extends into east centralWyoming north of the North Platte River. Thephysiography of the region consists of a smallwestern portion of the High Plains Section of theGreat Plains Province. The climate is arid withevapotranspiration greater than precipitation. Thesoil moisture regime is Aridic and the soiltemperature regime is Mesic. The soils are primarilyArgids and Aridic Ustolls. The major grasses of theBlue grama-Buffalograss Type of the Southern ShortGrass Prairie (table 8) are blue grama andbuffalograss. This vegetation type is separated fromthe Grama-Needlegrass-Wheatgrass Type because thearid soil moisture regime and mesic soil temperatureregime severely reduce the mid cool-season grassesand greatly increase the short warm-season grasses. Only a small area of the Southern Short Grass Prairieextends into the Northern Plains.

Sandhills Prairie

The Sandhills Prairie, Bluestem-Sandreed-Grama-Needlegrass Type (figure 1), exists in thenorth central portion of Nebraska south of the

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Niobrara River and north of the Platte River. OtherSandhills Prairie areas exist scattered throughout theNorthern Plains. Many areas are too small to map. Alarge area of Sandhills Prairie exists along theSheyenne River in southeastern North Dakota andanother large area exists near Swift Current,Saskatchewan. The physiography of the NebraskaSandhills consists of the Sand Hills region of theHigh Plains Section of the Great Plains Province. The climate is semi arid with evapotranspirationgreater than precipitation. The soil moisture regimeis Ustic and the soil temperature regime is Mesic. The soils are primarily Ustipsamments. The majorgrasses of the Bluestem-Sandreed-Grama-Needlegrass Type of the Sandhills Prairie (table 9)are big bluestem, little bluestem, sand bluestem,prairie sandreed, sideoats grama, needle and thread,and switchgrass. Prominent forbs are purple prairieclover, silky prairie clover, scurf peas, goldenrods,sunflowers, white camas, and wild lily. Major shrubsare leadplant, wild roses, western snowberry, willows,creeping juniper, common juniper, eastern red cedar,and yucca. This vegetation type is fundamentally theTall Grass Prairie vegetation on sand soils. The tallgrass species occupy the lower slopes andsubirrigated soils while the mid and short grassesoccupy the dryer upper slopes. A unique assemblageof grasses grow in blowout areas with active winderosion and deposition and are blowout grass,sandhill muhly, sand dropseed, indian ricegrass, andSchweinitz cyperus.

Foothills Prairie

The Foothills Prairie, Plains Rough FescueType (figure 1), exists as a fringe along the montaneforest of the Rocky Mountain foothills from Albertato south central Montana and along the aspengroveland and aspen parkland bordering the borealforest zone in Alberta and Saskatchewan and the typemingles with the Wheatgrass-Bluestem-NeedlegrassType extending across Saskatchewan andsouthwestern Manitoba and into northern NorthDakota. The physiography of the region consists ofthe northern portion of the Glaciated section of theMissouri Plateau Section of the Great Plains Provinceand the northern portion of the Small Lakes Sectionof the Central Lowland Province. The major grassesof the Plains Rough Fescue Type of the FoothillsPrairie (table 10) are plains rough fescue, Parry’soatgrass, timber oatgrass, bluebunch wheatgrass,slender wheatgrass, western wheatgrass, thickspikewheatgrass, Nelson’s needlegrass, and Richardson’sneedlegrass. Prominent forbs are lupines, talllarkspur, sticky-leaved geranium, and arrowleafbalsamroot. Major shrubs are shrubby cinquefoil and

big sagebrush. This vegetation type consists of a highproportion of tussock-forming grass species that arenow known to develop on other landforms thanRocky Mountain foothills.

Grassland with Woodland or Forest

The Pacific Bunchgrass Prairie, Bluebunch-Fescue Type (figure 1), exists in the south centralportion of Montana. Numerous other areas too smallto map exist within the Great Plains. Thephysiography of the region consists of theUnglaciated section of the Missouri Plateau Sectionof the Great Plains Province. The major grasses ofthe Bluebunch-Fescue Type of the PacificBunchgrass Prairie (table 11) are bluebunchwheatgrass, Idaho fescue, western wheatgrass,sideoats grama, and little bluestem. Prominent forbsare white prairie aster, western yarrow, Americanvetch, scarlet gaura, and fringed sage. Major shrubsare western snowberry, silver sagebrush, rabbitbrush,broom snakewood, and plains prickly pear. Thisvegetation type is commonly associated with bigsagebrush and exists as open grasslands betweensavanna stands of ponderosa pine or Rocky Mountainjuniper.

The Badlands and River Breaks, WoodyDraw and Savanna Types (figure 1), exist in centralMontana along the Missouri and Musselshell Rivers,in western North Dakota along the Little MissouriRiver, and in southwestern South Dakota along theWhite River. The physiography of the region consistsof the Unglaciated section of the Missouri PlateauSection of the Great Plains Province. The majorgrasses of the Woody Draw and Savanna Types of theBadlands and River Breaks (table 12) are westernwheatgrass, needle and thread, blue grama, greenneedlegrass, and prairie Junegrass. The grasslandcommunities of this vegetation type exist as opengrasslands or understory grasslands associated withthin stands of trees growing in highly eroded badlandareas, on steep east and north facing slopes, or insteep, sharply eroded breaks along streams and rivers. The woodlands and savannas consist primarily ofponderosa pine and Rocky Mountain juniper, and thehardwood draws consist of green ash, American elm,boxelder, and hawthorn. Major shrubs are wild roses,Juneberry, chokecherry, skunk bush, westernsnowberry, and shrubby cinequefoil.

The Pine Savanna, Pine-Juniper-BluebunchType (figure 1), exists on rough uplands in southcentral and southeastern Montana, north centralWyoming, western South Dakota, and southwesternNorth Dakota. The physiography of the region is the

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Unglaciated section of the Missouri Plateau Sectionof the Great Plains Province. The major grasses ofthe Pine-Juniper-Bluebunch Type of the PineSavanna (table 13) are bluebunch wheatgrass, westernwheatgrass, thickspike wheatgrass, needle and thread,blue grama, green needlegrass, and little bluestem. The grassland communities of this vegetation typeexist as open grasslands or understory grasslandsassociated with numerous disconnected savannastands of ponderosa pine and Rocky Mountainjuniper growing on eroded uplands with thin soils. Major shrubs are big sagebrush, bitterbrush, westernsnowberry, skunk bush, rabbitbrush, and commonjuniper.

The Black Hills Pine Forest, Pine-Spruce-Aspen Type (figure 1), exists in southwestern SouthDakota and northeastern Wyoming. Thephysiography of the region consists of the Black Hillssection of the Missouri Plateau Section of the GreatPlains Province. The major grasses of the Pine-Spruce-Aspen Type of the Black Hills Pine Forest(table 14) are western wheatgrass, bluebunchwheatgrass, needle and thread, green needlegrass,prairie Junegrass, and blue grama. The grasslandcommunities of this vegetation type exist as opengrasslands or understory grasslands associated withthe open park stands of ponderosa pine in the higherhills and with the savanna stands of ponderosa pine inthe lower hills. Grassland communities are notimportant in the deep cool canyons with dense, nearlyclosed stands of white spruce and paper birch, in thedense secondary growth of aspen and paper birch, orin the dense deciduous forest stands of green ash, buroak, American elm, boxelder, and hackberry alongstreams. Important shrubs are beaked hazelnut,Juneberry, chokecherry, willows, big sagebrush, sandsagebrush, and mountain mahogany.

The Montane Forest, Pine-Fir-Spruce Type(figure 1), exists on the Sweetgrass Hills, and theHighwood, Bearpaw, Little Rocky, Moccasin, Judith,and Big Snowy mountains in Montana and theCypress Hills in Saskatchewan. The physiography ofthe region consists of the laccolithic domedmountains in the Unglaciated section and theerosional upland remnant in the Glaciated section ofthe Missouri Plateau Section of the Great PlainsProvince. The major grasses of the Pine-Fir-SpruceType of the Montane Forest (table 15) are bluebunchwheatgrass, Idaho fescue, Nelson’s needlegrass, spikefescue, prairie Junegrass, needle and thread, andspike oatgrass. The grassland communities of thisvegetation type exist as open grasslands andunderstory grasslands associated with open stands ofponderosa pine and Douglas fir on the lower

elevations of the domed mountains. Prominent forbsare arrowleaf balsamroot, lupine, sticky-leavedgeranium, bluebells, and prairie smoke. Major shrubsare western snowberry, white spiraea, and bearberry. Grassland communities are not important at thehigher elevations with closed forest stands ofsubalpine fir, Douglas fir, and Engelmann spruce. Grassland communities are associated with the openforest stands of lodgepole pine, white spruce, paperbirch, and aspen on the Cypress Hills.

The Upland Woodlands, Aspen-Ash-Oak-Juniper Types (figure 1), exist as scattered areas withvarious types of trees, shrubs, and grasses in NorthDakota, Manitoba, and Saskatchewan. Thephysiography of the region consists of uplandpositions of the Small Lakes Section of the CentralLowland Province and of upland positions of theUnglaciated section of the Missouri Plateau Sectionof the Great Plains Province. The major grasses ofthe Aspen-Ash-Oak-Juniper Types of the UplandWoodlands (table 16) are roughleaf ricegrass, littlericegrass, and long-beaked sedge. Grass plants ofthese vegetation types are part of the understorycommunity. Prominent forbs are northern bedstraw,wild strawberry, violets, anise root, and blacksnakeroot. Major shrubs are beaked hazelnut,western snowberry, Juneberry, chokecherry, redraspberry, bittersweet, gooseberry, wild plum, andnorthern hawthorn. The aspen woodlands containtrembling aspen, balsam poplar, paper birch, greenash, and sometimes bur oak. The ash woodlandscontain green ash, American elm, boxelder, andoccasionally hackberry. The oak woodlands containbur oak, green ash, American elm, boxelder, aspen,and occasionally ironwood. The juniper woodlandscontain Rocky Mountain juniper.

The Riparian Woodlands, Cottonwood-Ash-Elm Type (figure 1), exists along the floodplains ofthe larger rivers and streams and as small grovesalong minor drainage ways located throughout theNorthern Plains. The major grasses of theCottonwood-Ash-Elm Type of the RiparianWoodlands (table 17) are Canada wildrye, slenderwheatgrass, Virginia wildrye, prairie sandreed, needleand thread, green needlegrass, marsh muhly, reedcanarygrass, prairie cordgrass, bottlebrush grass, andmountain ricegrass. The grassland communities ofthis vegetation type exist as understory grasslandsassociated with open woodlands and sometimes fairlydense forest stands of cottonwood, green ash,boxelder, American elm, hackberry, peach-leavedwillow, and occasionally bur oak. Prominent forbsare false solomon’s seal, dogbane, wild licorice,fringed loosestrife, and meadow rue. Major shrubs

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are western snowberry, wild roses, skunk bush, golden currant, gooseberry, dogwood, poison ivy,bittersweet, wild grape, thicket creeper, and westernclematis.

The environmental and biological factorsthat affect development of plant communities andvegetation types are the same factors that affect soildevelopment. Soil moisture regimes affectdistribution of plant species affiliations. The speciesaffiliations that are the major vegetation types in theNorthern Plains; Tall Grass Prairie, Transition MixedGrass Prairie, Mixed Grass Prairie, and Short GrassPrairie; coincide with the four soil moisture regimes;Perudic, Udic, Ustic, and Aridic; respectively. Thefour soil moisture regimes are further separated intotwo soil temperature regimes; Frigid in the northernportions and Mesic in the southern portions. Soiltemperature regimes affect composition anddistribution of cool-season and warm-season grasseswithin the vegetation types. In the northern Frigidtemperature regime, warm-season grass speciesdecrease and cool-season grass species increase. Inthe southern Mesic temperature regime, cool-seasongrass species decrease and warm-season grass speciesincrease.

Changes in elevation, slope, and aspectresulting from the various physiographic landforms inthe Northern Plains affect plant species topographicdistribution and plant community productivity bycausing differential distribution and retention of soilwater. Lower slopes have greater soil water thanupper slopes. East and north facing slopes retainmore soil water longer than south and west facingslopes. Lowland landscape slopes have soil water inamounts greater than precipitation levels because ofwater runin from upper slopes. Upland landscapeslopes have soil water in amounts similar toprecipitation levels because water runin and waterrunoff occur in low quantities and are about the same. Xeric landscape slopes have soil water in amountsless than precipitation levels because of restrictedwater infiltration, low water holding capacity, highevapotranspiration demand, and/or high water runoff.

Some slope positions have sufficiently lowevapotranspiration demand and/or receive sufficientquantities of water runin for woodland and forestplant communities to develop. Woodlands andforests also develop along rivers and streams and athigher elevation positions that receive greaterquantities of precipitation.

Enhancement of the Land Natural Resources

Generating greater new wealth withlivestock agriculture requires enhancement of theland natural resources. These essential changes aredoable and not the herculean task that they firstappear to be. A few small catalyzing changescorrectly timed can have remarkable effects.

The forces that change hills into valleys,rocks into clay, and forests into grasslands workslowly over thousands and millions of years. Thephysiographic landform characteristics have changedlittle during the past 10,000 years. The currentclimate with wet and dry periods, and the current soilmoisture and soil temperature regimes have beenoperational for about 5,000 years. The native plantspecies completed development of their physiologicalprocesses and defoliation resistance mechanisms inconjunction with early herbivore evolution millions ofyears ago.

By contrast, the soils, plant communities,and vegetation types in the Northern Plains arerelatively young and their development is stillongoing. These developmental processes can bemanipulated through implementation of biologicallyeffective management that benefits all living andnonliving ecosystem components by meeting thebiological requirements of the plants and soilorganisms which causes improvements in thebiogeochemical processes, ecosystem health, soilquality, plant community composition, and vegetationtype affiliations. These important improvementsenhance the quality and productivity of the landnatural resources and result in generation of greaternew wealth.

Acknowledgment

I am grateful to Sheri Schneider forassistance in production of this manuscript and fordevelopment of the tables.

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Table 1. Major Grasses of the Tall Grass Prairie; Bluestem-Switchgrass-Indiangrass Type.

Standardized Common Name Flora of the Great Plains1986

Flora of North America2003, 2007

Big bluestem Andropogon gerardii Andropogon gerardii

Porcupinegrass Stipa spartea Hesperostipa spartea

Switchgrass Panicum virgatum Panicum virgatum

Prairie dropseed Sporobolus heterolepis Sporobolus heterolepis

Indiangrass Sorghastrum nutans Sorghastrum nutans

Northern reedgrass Calamagrostis stricta Calamagrostis stricta inexpansa

Prairie cordgrass Spartina pectinata Spartina pectinata

Sideoats grama Bouteloua curtipendula Bouteloua curtipendula

Slender wheatgrass Agropyron caninum majus majus

Elymus trachycaulus trachycaulus

Bearded wheatgrass Agropyron caninum majus unilaterale

Elymus trachycaulus subsecundus

Kentucky bluegrass Poa pratensis Poa pratensis

Needle and thread Stipa comata Hesperostipa comata

Little bluestem Andropogon scoparius Schizachyrium scoparium scoparium

Mat muhly Muhlenbergia richardsonis Muhlenbergia richardsonis

Needleleaf sedge Carex eleocharis Carex duriuscula

Sun sedge Carex heliophila Carex inops heliophila

Woolly sedge Carex lanuginosa Carex pellita

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Table 2. Major Grasses of the Transition Mixed Grass Prairie; Wheatgrass-Bluestem-Needlegrass Type.



Western wheatgrass Agropyron smithii Pascopyrum smithii

Thickspike wheatgrass Agropyron dasystachyum Elymus lanceolatus




Green needlegrass Stipa viridula Nassella viridula

Bearded wheatgrass Agropyron caninum majus unilaterale

Elymus trachycaulus subsecundus




Blue grama Bouteloua gracilis Bouteloua gracilis

Prairie Junegrass Koeleria pyramidata Koeleria macrantha

Prairie sandreed Calamovilfa longifolia Calamovilfa longifolia




Threadleaf sedge Carex filifolia Carex filifolia


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Table 3. Major Grasses of the Mixed Grass Prairie; Wheatgrass-Needlegrass Type.








Plains reedgrass Calamagrostis montanensis Calamagrostis montanensis



Sandberg bluegrass Poa sandbergii Poa secunda




Small needlegrass Stipa curtiseta Hesperostipa curtiseta

Bluebunch wheatgrass Agropyron spicatum Pseudoroegneria spicata

Buffalograss Buchloe dactyloides Buchloe dactyloides




16

Table 4. Major Grasses of the Mixed Grass Prairie on Clay Soils; Wheatgrass-Grama Type.








Table 5. Major Grasses of the Mixed Grass Prairie on Dense Clay Soils; Wheatgrass Type.






Associated Grass


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Table 6. Major Grasses of the Northern Short Grass Prairie; Grama-Needlegrass-Wheatgrass Type.










Associated Grasses

Red threeawn Aristida purpurea robusta Aristida purpurea longiseta

Indian ricegrass Oryzopsis hymenoides Achnatherum hymenoides

Plains muhly Muhlenbergia cuspidata Muhlenbergia cuspidata



Deteriorated Grassland

Cheatgrass Bromus tectorum Bromus tectorum

Japanese brome Bromus japonicus Bromus japonicus

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Table 7. Major Grasses of the Northern Short Grass Prairie on Salty Soils; Saltgrass Type.



Saltgrass Distichlis spicata stricta Distichlis spicata

Alkali cordgrass Spartina gracilis Spartina gracilis

Basin wildrye Elymus cinereus Leymus cinereus

Foxtail barley Hordeum jubatum Hordeum jubatum jubatum

Little barley Hordeum pusillum Hordeum pusillum

Nuttall’s alkali grass Puccinellia nuttalliana Puccinellia nuttalliana

Common squirreltail Sitanion hystrix Elymus elymoides elymoides

Tumblegrass Schedonnardus paniculatus Schedonnardus paniculatus

Table 8. Major Grasses of the Southern Short Grass Prairie; Blue grama-Buffalograss Type.





Associated Grasses



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Table 9. Major Grasses of the Sandhills Prairie; Bluestem-Sandreed-Grama-Needlegrass Type.





Sand bluestem Andropogon hallii Andropogon hallii




Switchgrass Panicum virgatum Panicum virgatum


Blowout Areas

Blowout grass Redfieldia flexuosa Redfieldia flexuosa

Sandhill muhly Muhlenbergia pungens Muhlenbergia pungens

Sand dropseed Sporobolus cryptandrus Sporobolus cryptandrus

Indian ricegrass Oryzopsis hymenoides Achnatherum hymenoides

Schweinitz cyperus Cyperus schweinitzii Cyperus schweinitzii

20

Table 10. Major Grasses of the Foothills Prairie; Plains Rough Fescue Type.



Plains rough fescue Festuca scabrella Festuca hallii

Parry’s oatgrass Danthonia parryi Danthonia parryi

Timber oatgrass Danthonia intermedia Danthonia intermedia






Nelson’s needlegrass Stipa columbiana Achnatherum nelsonii nelsonii

Richardson’s needlegrass Stipa richardsonii Achnatherum richardsonii



Idaho fescue Festuca idahoensis Festuca idahoensis

Spike oatgrass Helictotrichon hookeri Avenula hookeri



Deteriorated Grassland

Cheatgrass Bromus tectorum Bromus tectorum

Japanese brome Bromus japonicus Bromus japonicus

21

Table 11. Major Grasses of the Pacific Bunchgrass Prairie; Bluebunch-Fescue Type.








Red threeawn Aristida purpurea robusta Aristida purpurea longiseta


Plains muhly Muhlenbergia cuspidata Muhlenbergia cuspidata




22

Table 12. Major Grasses of the Badlands and River Breaks; Woody Draw and Savanna Types.








Plains reedgrass Calamagrostis montanensis Calamagrostis montanensis








Saltgrass Distichlis spicata stricta Distichlis spicata

23

Table 13. Major Grasses of the Pine Savanna; Pine-Juniper-Bluebunch Type.










24

Table 14. Major Grasses of the Black Hills Pine Forest; Pine-Spruce-Aspen Type.









Hairy grama Bouteloua hirsuta Bouteloua hirsuta




Table 15. Major Grasses of the Montane Forest; Pine-Fir-Spruce Type.





Nelson’s needlegrass Stipa columbiana Achnatherum nelsonii nelsonii

Spike fescue Hesperochloa kingii Leucopoa kingii



Spike oatgrass Helictotrichon hookeri Avenula hookeri


25

Table 16. Major Grasses of the Upland Woodlands; Aspen-Ash-Oak-Juniper Types.



Roughleaf ricegrass Oryzopsis asperifolia Oryzopsis asperifolia

Little ricegrass Oryzopsis micrantha Piptatherum micranthum

Long-beaked sedge Carex sprengelii Carex sprengelii


Associated Grasses







26

Table 17. Major Grasses of the Riparian Woodlands; Cottonwood-Ash-Elm Type.



Canada wildrye Elymus canadensis Elymus canadensis



Virginia wildrye Elymus virginicus Elymus virginicus




Marsh muhly Muhlenbergia racemosa Muhlenbergia racemosa

Reed canarygrass Phalaris arundinacea Phalaris arundinacea

Prairie cordgrass Spartina pectinata Spartina pectinata

Bottlebrush grass Hystrix patula Elymus hystrix

Mountain ricegrass Oryzopsis racemosa Piptatherum racemosum


Yellow sedge Carex pensylvanica Carex pensylvanica

Long-beaked sedge Carex sprengelii Carex sprengelii

27

Literature Cited

Barker, W.T., and W.C. Whitman. 1989. Vegetation of the Northern Great Plains. North Dakota State University ExperimentStation Research Report #111. Fargo, ND. 26p.

Baumberger, R. 1977. South Dakota rangelandresources. Old West Regional Commission.Society for Range Management, Denver,CO. 150p.

Bluemle, J.P. 2000. The face of North Dakota. Third Edition. North Dakota GeologicalSurvey. Educational Series 26. 205p.

Bose, D.R. 1977. Rangeland resources of Nebraska. Old West Regional Commission. Societyfor Range Management, Denver, CO. 121p.

Brady, N.C. 1974. The nature and properties ofsoils. MacMillan Publishing Co., Inc., NewYork, NY. 639p.

Clarke, S.E., J.A. Campbell, and J.B. Campbell. 1942. An ecological and grazing capacitystudy of the native grass pastures in southernAlberta, Saskatchewan, and Manitoba. Division of Forage Crops Dom. ExperimentStation. Technical Bulletin 44. SwiftCurrent, SK. 31p.

Coupland, R.T., and T.C. Brayshaw. 1953. Thefescue grassland in Saskatchewan. Ecology34:386-405.

Coupland, R.T. 1950. Ecology of mixed prairie inCanada. Ecological Monographs 20:271-315.

Coupland, R.T. 1961. A reconsideration ofgrassland classification in the NorthernGreat Plains of North America. Journal ofEcology 49:135-167.

Fenneman, N.M. 1931. Physiography of westernUnited States. McGraw-Hill BookCompany, New York, NY. 534p.

Fenneman, N.M. 1946. Physical divisions of theUnited States. USDI Geological Survey. Map.

Flora of North America Editorial Committee, eds. 2003, 2007. Flora of North America. Oxford University Press, New York, NY. Vols. 24-25.

Froiland, S.G., and R.R. Weedon. 1990. Naturalhistory of the Black Hills and badlands. TheCenter for Western Studies, Sioux Falls, SD. 225p.

Goodin, J.R., and D.K. Northington (eds.). 1985. Plant resources of arid and semiarid lands. Academic Press, Inc., Orlando, FL. 338p.

Great Plains Flora Association. 1986. Flora of theGreat Plains. University Press of Kansas, Lawrence, KS. 1392p.

Hacker, P.T., and T.P. Sparks. 1977. Montanarangeland resources. Old West RegionalCommission. Society for RangeManagement, Denver, CO.

Hunt, C.B. 1974. Natural regions of the UnitedStates and Canada. W.H. Freeman andCompany, San Francisco, CA. 725p.

Kaul, R.B. 1975. Vegetation of Nebraska (Circa1850). Conservation and Survey Division,Institute of Agriculture and NaturalResources, University of Nebraska, Lincoln,NE. Map.

Kuchler, A.W. 1964. Potential natural vegetation ofthe conterminous United States. AmericanGeographical Society. Special PublicationNo. 36. New York, NY. 116p. + Maps.

Moss, E.H., and J.A. Campbell. 1947. The fescuegrassland of Alberta. Canadian Journal ofResearch. 25:209-227.

Ojakangas, R.W., and C.L. Matsch. 1982. Minnesota’s Geology. University ofMinnesota Press, Minneapolis, MN. 255p.

Raisz, E. 1957. Landforms of the United States. Copyrighted Erwin Raisz Map.

Robinson, C.S., and R.E. Davis. 1995. Geology ofDevils Tower National Monument. DevilsTower Natural History Association, WY. 96p.

28

Ross, R.L., and H.E. Hunter. 1976. Climaxvegetation of Montana based on climate andsoils. USDA, Soil Conservation Service. Bozeman, MT. 64p.

Shaver, J.C. 1977. North Dakota rangeland resources. Old West Regional Commission. Society for Range Management, Denver,CO. 118p.

Shrader, J.A. 1977. Wyoming rangeland resources. Old West Regional Commission. Society for Range Management, Denver,CO. 87p.

Soil Survey Staff. 1975. Soil taxonomy. USDAAgriculture Handbook No. 436. Washington, DC. 754p.

Whitman, W.C., and W.T. Barker. 1989. Mapping North Dakota’s natural vegetation. Proceedings of the North Dakota Academyof Science. 43:4-5.

29

Seasonal Weather Patterns of the Northern Plains



Precipitation Pattern

The current climate of the Northern Plainshas existed for the past 5,000 years (Bluemle 1977,Bluemle 1991, Manske 1994, Bluemle 2000). Theseasonal distribution of precipitation (figure) isclassified as the Plains Precipitation Pattern(Humphrey 1962), in which most of the precipitationoccurs during the growing season (85%) and thesmallest amount occurs in winter (10%). Totalprecipitation for the 5-month nongrowing season ofNovember through March averages less than 2.5inches (63.5 mm) (15%) of precipitation. Thegreatest amount of precipitation occurs in spring andearly summer (60%). The precipitation received inthe 3-month period of May, June, and July accountsfor over 50% of the annual precipitation, and Junehas the greatest monthly precipitation (22%).

Weather Air Mass Pattern

The weather of the Northern Plains iscontrolled by three major air masses that dominate atdifferent times of the year (Redmann 1968). ThePacific air mass dominates the region from Septemberthrough January, a period that is generally drybecause the orographic effect of the Rocky Mountainscauses a rain shadow as the air mass moves east. Themean monthly precipitation during this dry period isless than 1.0 inch (25.4 mm). The Polar air massdominates the region from February through May, aperiod with mean monthly precipitation between 1.0and 2.0 inches (25.4 mm and 50.8 mm). ThroughoutJune, combinations of Gulf, Polar, and Pacific airmasses mix and produce a relatively rainy period witha monthly precipitation average around 3.5 inches(88.9 mm). The summer months of July and Augustare dominated by the Gulf air mass, with little mixingof other air masses and a reduction of monthlyprecipitation to about 2.0 inches (50.8 mm), whichcomes generally in intermittent thunderstorms. Thechange from the dominance of one air mass to thenext results in transition periods, which can varyannually. Differences in the transition periodscontribute to the variation in conditions from year toyear.

Literature Cited

Bluemle, J.P. 1977. The face of North Dakota: thegeologic story. North Dakota Geological Survey. Ed. Series 11. 73p.

Bluemle, J.P. 1991. The face of North Dakota.Revised edition. North Dakota GeologicalSurvey. Ed. Series 21. 177p.

Bluemle, J.P. 2000. The face of North Dakota. 3rd edition. North Dakota Geological Survey. Ed. Series 26. 206p. 1pl.

Humphrey, R.R. 1962. Range ecology. TheRonald Press Company. New York, NY. 234p.

Manske, L.L. 1994. History and land use practicesin the Little Missouri Badlands and western North Dakota. Proceedings-Leafy spurge strategic planning workshop. USDINational Park Service. Dickinson, ND. p. 3-16.

Redmann, R.E. 1968. Productivity and distributionof grassland plant communities in western North Dakota. Ph.D. Thesis, University ofIllinois. IL. 153p.

30

Soil Formation in the Unglaciated Northern Plains



Soil is the medium in which grassland plantsgrow. Major variations in soil properties result fromdifferences in the type of parent material and in thesoil developmental processes. Plant communitydynamics and plant growth potentials are affected bythe changing characteristics occurring during thecontinuous progression of soil formation, and soil,climate, and plants have complex cause-effectrelationships regulating soil formation. Managementpractices affect these relationships and can enhanceor impair soil developmental processes.

Parent Material from Sedimentary Deposits

The unglaciated region of the NorthernPlains is part of a large geologic depression, whichhas been filled over a period of 515 million yearswith accumulations of sedimentary rocks deposited inoff-shore shallow seas and in near-shore marineenvironments or by running water on floodplains ordeltas. For about the last 5 million years, runningwater and wind have been eroding the generally flat-lying sedimentary deposits in the unglaciated region. These erosional forces have been selective in theiraction because hard, relatively resistant sandstone,limestone, scoria, chert, or other erosion-resistantmaterials were present in some of the sedimentarydeposits and have remained as protective caps, whilethe soft, weakly consolidated, less resistant silt andclay layers have been easily washed or blown away. The landforms that have resulted from unevensediment removal are gently rolling to hilly plainsintermingled with buttes, which have flat tops andsteep slopes. Over the last 600,000 years, badlandstopography has developed near some streams andrivers from erosional forces that accelerated sedimentremoval when glacial ice blocked the northward flowof the drainage systems. The diverted routes to theeast were shorter and steeper, and the water flowingin the drainage systems caused deep, rapid erosionthat resulted in badlands landforms (Hunt 1974,Bluemle 1977, Trimble 1990, Bluemle 1991,Bluemle 2000).

Soil Development from Sedimentary Deposits

Soils in the unglaciated region have beendeveloping from weathered sedimentary deposits of

soft shale, siltstone, and sandstone. Soil formation isa long, slow, continuous process. Temperatures andprecipitation levels of the area have been important inthe development of the regional soils. The climatehas determined the type of vegetation and the amountof annual growth, which, in turn, have influenced theamount of soil organic matter accumulated.

Temperature affects the rate of oxidation oforganic matter. Higher temperatures promote rapidoxidation of organic matter, and soils in regions withlong periods of high temperatures contain littleorganic matter. Little or no oxidation of organicmatter occurs in frozen soil. Organic matter hasaccumulated in the soils in the Northern Plainsbecause the climate has cold periods during whichlittle chemical activity takes place. In most years,soils in the unglaciated region have frost penetrationto a depth of 3 to 5 feet for a period of approximately120 days (Larson et al. 1968), a condition thatcontributes to soil organic matter accumulation. Thedark surface layer of most soils in the region has anaccumulation of 2 to 5% organic matter (Larson et al.1968, Wright et al. 1982).

Temperature and precipitation haveinfluenced the amount and kinds of physical andchemical weathering of the region’s parent material. High temperatures and high precipitation haveencouraged rapid weathering and clay formationduring the summer, while low temperatures duringfall, winter, and early spring have caused cracks,fissures, and breaks in the parent material anddeveloping soil as a result of the expansion andcontraction forces of frost.

Precipitation level has influenced the amountof water in the soil. The amount of water that hasentered the soil has not been the same as theprecipitation level, and the amount of soil water hasnot been the same on all parts of the landscape. Theamount of soil water has been less than the amount ofprecipitation received in areas that have had rain runoff, and the amount of soil water has been greaterthan the amount of precipitation received in areas thathave had rain run in. The amount of soil waterpresent has affected the rate of leaching. The depthof the downward movement of the water has not been

32

uniform for the soils on different topographicpositions on the landscape.

Soil water has dissolved calcium carbonate(lime), soluble salts, exchangeable sodium, and clayparticles from the upper horizons of the soil andmoved them downward into a lower horizon. Theamount of these dissolved materials in the soil profilehas been dependent on the amount present in theweathered parent material. The depth to which theyhave been moved has varied with the amount of soilwater. The layer where the dissolved material hasaccumulated indicates the approximate average depthof downward water movement. The depth of theaccumulation layer decreases when the precipitationdecreases. Soils with a high lime content havedeveloped a layer of natural cement (hardpan) thatrestricts plant root penetration. Soils high in solublesalts and/or exchangeable sodium have developedaccumulation layers containing sufficient amounts ofthese chemicals to impair plant growth. Soils high insoluble salts have developed into saline soils; soilshigh in exchangeable sodium have developed intosodic soils; and soils high in both have developed intosaline-sodic soils (Omodt et al. 1968, Soil SurveyStaff 1975, Foth 1978).

Soil water has also dissolved clay particlesand moved the clay downward. When the soil waterwith dissolved clay has hit areas of dry soil, the waterhas been withdrawn and the clay particles have beendeposited. Over time this clay film layer has built upto form what is called an argillac horizon. Lowamounts of argillac horizon in a soil can be beneficialbecause the clay helps increase the amount of waterand nutrients stored in that zone; however, when theclay accumulation becomes great, the effects can bedetrimental because water movement and plant rootpenetration are severely restricted. Soils that have awell-developed argillac horizon are called clay-pansoils (Omodt et al. 1968, Soil Survey Staff 1975, Foth1978).

The depth of the layer where the dissolvedmaterial accumulates is very important because itdetermines the thickness of the plant growth medium;the soil above the layer of accumulation holds thenutrients and soil water needed to sustain plant life. Shallow soils restrict plant growth. The depth of theaccumulation layer decreases westward with thereduction in precipitation and ranges from 6 inches to4 feet. Most soils in western North Dakota haveformed the accumulation layer between 15 and 24inches below the soil surface (Larson et al. 1968,Omodt et al. 1968, Soil Survey Staff 1975, Foth1978, Wright et al. 1982).

Literature Cited

Bluemle, J.P. 1977. The face of North Dakota: thegeologic story. North Dakota Geological Survey. Ed. Series 11. 73p.

Bluemle, J.P. 1991. The face of North Dakota.Revised edition. North Dakota GeologicalSurvey. Ed. Series 21. 177p.

Bluemle, J.P. 2000. The face of North Dakota. 3rd edition. North Dakota Geological Survey. Ed. Series 26. 206p. 1pl.

Foth, H.D. 1978. Fundamentals of soil science. John Wiley and Sons. New York, NY. 436p.

Hunt, C.B. 1974. Natural regions of the UnitedStates and Canada. W.H. Freeman andCompany. San Francisco, CA. 725p.

Larson, K.E., A.F. Bahr, W. Freymiller, R.Kukowski, D. Opdahl, H. Stoner, P.K.Weiser, D. Patterson, and O. Olsen. 1968.Soil survey of Stark County, North Dakota.U.S. Government Printing Office.Washington, DC. 116p.+plates.

Omodt, H.W., G.A. Johnsgard, D.D. Patterson,and O.P. Olson. 1968. The major soils ofNorth Dakota. Department of Soils. Bulletin No. 472. North Dakota StateUniversity. Fargo, ND. 60p.+map.

Soil Survey Staff. 1975. Soil Taxonomy. Agriculture Handbook No. 436. USDA SoilConservation Service. U.S. GovernmentPrinting Office. Washington, DC. 754p.

Trimble, D.E. 1990. The geologic story of theGreat Plains. Theodore Roosevelt Natureand History Association. Medora, ND. 54p.

Wright, M.R., J. Schaar, and S.J. Tillotson. 1982. Soil survey of Dunn County, North Dakota.U.S. Government Printing Office. Washington, DC. 235p.+plates.

33

Prehistorical Conditions of Rangelands in the Northern Plains

Llewellyn L. Manske PhDReport DREC 08-3015b Range Scientist

North Dakota State University Dickinson Research Extension Center

An accurate representation of the NorthernPlains rangelands does not match the static romanticimage of a vast, ageless, pristine grassland inexcellent health, with large herds of free-roamingbison accompanied by elk, antelope, wolves, andgrizzly bears in idealistic harmony. The presentgrassland assemblage of communities and ecosystemsin the Northern Plains started to develop only about5,000 years ago, and the plants that migrated into theregion respond to environmental changesdynamically, with shifts in species composition andbiological status. Populations of plants and animalsin grassland ecosystems experience peaks and crashesin cycles of variable highs, lows, and duration, inresponse to the complex set of interrelated forces inthe environment. Grassland ecosystems have neverbeen static nor can they be managed to remain at anidealistic static goal. Most idealistic staticmanagement goals for grasslands are based on aperceived image of “presettlement conditions” thatevokes strong nostalgia but does not provide acomplete set of guidelines on which to base soundgrassland management. To formulate an accuraterepresentation of the integral parts of the NorthernPlains grasslands and to develop an understanding ofthese interrelated processes we must look further backin time at the environmental forces and the processeswithin the plants and the ecosystems.

Climate

The climate of the Northern Plains haschanged several times during geologic history. Amajor climate change resulted when the RockyMountains began to uplift about 70 to 80 millionyears ago, forming a barrier that prevented humidPacific Ocean air masses from flowing eastward. The Plains became much drier. Two million years ago theclimate became cooler and more humid, with severalperiods of glaciation. Glacial advances occurredduring periods when the winter snow accumulation ontop of the glacier was greater than the amount of icemelted during the summer. The periods of glacialadvance were cool and humid, the interglacial periodswarmer and drier.

The changes in climate since the last glaciation period, which occurred between 100,000

and 10,000 years ago, have strongly influenced thepresent conditions of the region. The last ice sheetreached its maximum advance between 14,000 and12,000 years ago. About 10,000 years ago, a suddenchange in the climate to drier and warmer summersbut colder winters occurred. This major changeaccelerated the melting of the glacial ice. A spruce-aspen forest developed in the cool, moist conditionsat the ice margin; this community graded into adeciduous forest, which graded into a grassland southof the Northern Plains. The climate was much drierand warmer for the period between 10,000 and 5,000years ago. During the period between 8,500 and4,500 years ago, the vegetation was a sage and shortgrass plant community similar to vegetation in partsof Wyoming, and the region experienced frequentsummer droughts and extensive soil erosion fromwind (Bluemle 1977, Bluemle 1991).

The climate changed about 5,000 years agoto conditions like those of the present, with cycles ofwet and dry periods (Bluemle 1977, Bluemle 1991,Manske 1994). The wet periods have been cool andhumid, with greater amounts of precipitation. A briefwet period occurred around 4,500 years ago. Relatively long periods of wet conditions occurredbetween 2,500 and 1,800 years ago and between1,000 and 700 years ago. Recent short wet periodsoccurred from 1905 to 1916, 1939 to 1947, and 1962to 1978. During the wet periods, the vegetationchanged, with increases in taller grasses anddeciduous woodlands. The dry periods have beenwarmer, with reduced precipitation and recurrentsummer droughts. A widespread, long drought periodoccurred between 1270 and 1299, and more recentdrought periods occurred in the 1860's and from 1895to 1902, 1933 to 1938, and 1987 to 1992 (Manske1994). During the dry periods, the vegetationchanged, with decreases in woodlands and increasesin grasslands, and the plant composition shifted fromtaller grass species to shorter grass species. Thisclimatic pattern with cyclical changes in amounts ofprecipitation oscillating between wet and dry periodshas caused noticeable changes in the plant speciescomposition as it shifted from deciduous woodlandspecies to tall grass, mixed grass, short grass, anddesert shrub plant communities, then reversed the

34

cycling process, returning to increases in tallergrasses and woodland plants.

Vegetation

The plant species in this region originated inother areas and migrated into the Northern Plains bydifferent mechanisms and at different times and rates. The present vegetation has plant species withaffinities to the tall grass, mixed grass, and short grassprairies, deciduous and coniferous forests, and RockyMountain and desert shrub plant communities(Zaczkowski 1972). This wide mix of plant speciesin the Northern Plains formed from remnants of plantcommunities that reached periods of greaterdevelopment during the periods of wet and dry cycleswhen conditions favored these various plantcommunity types. The diversity of plant species inour native plant community permits it to responddynamically to changes in climatic conditions byincreasing the plant species favored by any set ofconditions.

The grass plants that migrated into theNorthern Plains had previously developed biologicalmechanisms to exist and thrive with defoliation bygrazing herbivores. This evolutionary process startedmillions of years ago. The earliest grass fossilsappeared in the late Tertiary Period during the timewhen the earth’s climate was becoming cooler anddrier as a result of the build up of an ice cap at thesouth pole on Antarctica. The earth’s lush tropicaland subtropical forests diminished and movedsouthward, and grasslands expanded and movednorthward. Grass species evolved quickly during thelower Miocene Epoch, 20 million years ago,developing characteristics that are similar to those ofpresent grasses and that identify these plants tomodern genera.

Grass plants and grazing mammals evolved together (Manske 1994). During the period ofcoevolution with herbivores, grasses developeddefoliation resistance mechanisms like hormonalgrowth regulation and symbiotic soil organismrelationships as compensatory processes to grazing. Close cropping of plants by herbivores exertedselective pressure that improved the survival ofgrasses over that of other plants and promotedgrassland expansion.

Herbivores

Grazing mammals appeared in the fossilrecord at about the same time as grass plants. Theearly grazing mammals had cecal fermentation

digestive systems (small horses, rhinoceroses, tapirs,brontotheres, and chalicotheres) and primitiveruminant digestive systems (camels and oreodonts). Herbivore characteristics changed and improved inresponse to changing characteristics in grasses. Grassplants developed a complex chemical compositionand deposited silicates in their tissue, rendering ittough and nearly indigestible. Herbivores developeddeep, hard teeth with enamel ridges on the crownsand digestive systems with improved effectiveness. Increased predatory pressure on open grasslands ledto herbivores’ development of longer legs with hornyhooves, and increases in overall body size. The latestand most successful group of herbivores to evolveduring this coevolutionary process was the bovine(deer, sheep, cattle, and antelope), which haveadvanced true ruminant digestive systems, long legs,and hard, moon-shaped cusps on their teeth. Bisonare an advanced bovine with a true ruminant digestivesystem, fast legs, and hard teeth. Early bisonmigrated to North America from Asia about a millionyears ago. The early populations remained small inresponse to competition. Bison have changed formseveral times, with a gradual decrease in body andhorn size.

Several large mammals became extinct inNorth America between 10,000 and 8,000 years ago,after the sudden climatic change that set offecological changes in the vegetation communities. Most paleontologists believe that these largemammals could have adjusted to the climate changehad extra pressure from human hunters not altered thebirth-death ratios and had increased competition forforage resources not disadvantaged territorial animalsand given herding animals a survival advantage. Themastodon, mammoth, camel, tapir, sloth, horse, largelong-horned bison, middle-sized bison, and dire wolfbecame extinct during this time. Caribou, musk oxen,and the small bison survived the climate change,hunting pressure, and forage competition. Thedramatic success of the bison following this periodresulted in part from the extermination of previousprairie competitors. The small bison was thedominant herbivore between 5,000 and 115 years ago(Manske 1994). Domestic cattle have been thedominant herbivore on Northern Plains rangelands forover one hundred years.

Humans

The early human inhabitants of the Northern Plains were descendants of Asian immigrants whomoved across the Bering Land Bridge between19,000 and 14,000 years ago (Snow 1989,Wormington 1957). They later moved into this

35

region at the time of the retreating ice sheet. Thesepeople lived in small family groups, traveled andtraded over long distances, and do not appear to haveclaimed territories. They had fire for warmth andcooking, used well-made stone-tipped spears to huntlarge game animals, and conducted hunting as anefficient, coordinated group activity. These peopleused fire intentionally as a hunting aid to change thevegetation to attract herds of game animals to adesired region (Bryan 1991, Holder 1970). Duringthe early portion of human occupation in the Northern Plains, many types of large herbivores roamed theregion and were used for food. Following a climatechange about 10,000 years ago, the availability ofgame animals decreased for several thousand years,and the humans made a noticeable shift in their dietby increasing the use of plants. During this period,humans intentionally distributed seeds of food plantsacross the territory. Starting around 2,250 years ago,the inhabitants cultivated large plots of arable land forproduction of domesticated food plants (Manske1994).

Conclusion

The rangelands of the Northern Plains arehighly advanced, complex ecosystems that functionsimilarly to living organisms, with response andfeedback processes. Defoliation by herbivores is aprocess grass plants require at specific growth stagesif healthy productive rangelands are to be maintained. Attempting to develop modern grazing managementpractices that emulate a perceived model of bisonmovement is naive. Grass plants developed theirbiological processes of defoliation resistancemechanisms 20 million years ago in areas outside theNorthern Plains and in conjunction with earlyherbivores that are now extinct. Grass plantsmigrated from numerous types of environments intothe Northern Plains and initiated development ofdynamic plant communities only about 5,000 yearsago, when the present climatic pattern started. Themodern small bison did not coevolve with the grassspecies of the Northern Plains but migrated from Asiato North America about a million years ago. Thelarge herds did not develop before 5,000 years ago. The bison has played a role in plant communitydynamics and plant species composition, but it wasnot a part of the fauna when the grasses developedtheir biological mechanisms in resistance todefoliation. The 5000-year tenure of the bison onNorthern Plains grasslands has the same relationshipto the 20-million-year age of the grass plants as 6.8days has to the age of a 75-year-old person. In order to be successful and maintain a healthy productive grassland ecosystem in the Northern Plains, modern

grazing management practices must meet the grassplants’ biological requirements as the first priority.

Management Implications

A. The present rangeland ecosystems haveexisted in the Northern Plains for only about5,000 years, and the plant communities arestill developing.

B. The normal Northern Plains climatic patternis cyclical between wet and dry periods andcauses changes in plant species composition,with periodic increases and decreases inwoody plants and increases and decreases intaller and shorter grasses.

C. Plants on the Northern Plains rangelandsoriginated elsewhere and migrated into theregion, developing dynamic plantcommunities in place.

D. Plants developed defoliation resistancemechanisms during coevolution withherbivores prior to migration into the regionand require defoliation at specific growthstages to remain healthy and productive.

E. The early herbivores that coevolved withgrass plants in North America are extinct. All extant herbivores require control ofgrazing patterns so that plant requirementsare met.

F. Humans lived in the Northern Plains prior tothe development of the present rangelandecosystems and have used varioustechniques and practices to manipulateherbivore movement and plant growth. Theinhabitants distributed seeds of food plantsacross the region and cultivated arable landfor food plant production from about 2,250years ago.

Acknowledgment

I am grateful to Amy M. Kraus and Naomi J.Thorson for assistance in preparation of thismanuscript. I am grateful to Sheri Schneider forassistance in production of this manuscript.

36

References

Barker, W.T., and W.C. Whitman. 1988. Vegetation of the Northern Great Plains. Rangelands 10:266-272.

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Bluemle, J.P. 1991. The face of North Dakota:revised edition. North Dakota GeologicalSurvey. Ed. Series 21. 177p.

Branson, F.A. 1985. Vegetation changes onwestern rangelands. Society for RangeManagement. Denver, CO. 76p.

Bryan, L. 1991. The buffalo people. University ofAlberta Press. Edmonton, Alberta. 215p.

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Eyre, S.R. 1963. Vegetation and soils, a worldpicture. Aldine Publishing Co. Chicago, IL. 324p.

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Gilmore, M.R. 1991. Uses of plants by the Indiansof the Missouri River Region. University ofNebraska Press. Lincoln, NE. 125p.

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Range Management Practices Addressing Problems Inherent in the Northern Plains Grasslands

Llewellyn L. Manske PhDReport DREC 08-3002c Range Scientist


Range management practices that arebiologically effective address the inherent problemsand conditions of the geographic region in which thepractices are implemented. In the Northern Plainsgrassland ecosystems, the vegetation is characterizedby three major features that have implications foranimal production: 1) plant growth is limited byseveral environmental factors, 2) ungrazed grasses arelow in nutritional quality during the latter portion ofthe grazing season, and 3) plants grazed too early inthe growing season or late in the growing seasonsuffer negative effects. The twice-over rotationgrazing system on native rangeland withcomplementary domesticated grass spring and fallpastures was developed with consideration of thesefeatures and has been successfully implementated onthe Northern Plains.

In this region, the most important of theenvironmental factors limiting plant growth (Manske1998) are moderate annual precipitation, limiteddistribution of precipitation during part of thegrowing season, cool temperatures in the spring andfall, and hot temperatures in summer. The seasonalprecipitation pattern is characterized by a period ofmaximum precipitation in late spring and earlysummer, tapering off to a moderately light amountduring fall and winter. Periods with precipitationlevels sufficiently low to place plants under waterstress and limit growth occur frequently. Herbageproduction within grassland communities is alsolimited by temperature. The frost-free period isusually short, from 120 to 130 days. Perennialgrassland plants can sustain growth for longer thanthe frost-free period, but they require temperaturesabove the level that freezes water in plant tissue andsoil. Plant growth is greatly limited by low airtemperatures during the early and late portions of thegrowing season and by high temperatures, highevaporation, drying winds, and low precipitationduring mid summer.

The growing season for perennial grassescovers about six months, from mid April to midOctober. However, because favorable precipitationand temperature conditions occur during May, June,and July (Manske 1998), most plant growth in height

is attained within this three-month period (Goetz1963). Peak aboveground herbage biomass is usuallyreached during the last ten days of July. Herbagebiomass of ungrazed plants increases in weight duringMay, June, and July; after the end of July the weightof the herbage biomass decreases because the rate ofsenescence (aging) of the grass leaves exceeds growthand the cell material in aboveground structures isbeing translocated to the belowground structures. This translocation causes a decrease in the nutritionalquality of the aboveground structures. Ungrazedplants of the major upland sedges, cool-seasongrasses, and warm-season grasses drop below the9.6% crude protein level around mid July (Whitmanet al. 1951), as they attain maximum growth in heightand weight.

The nutritional quality of the nativevegetation during the latter portion of the grazingseason is a limiting factor in animal performance. A1000-pound lactating cow requires a crude proteinlevel of at least 9.6% (NRC 1996). Most ruminantanimals require a daily dry matter intake of about 2%(1.5-3.0%) of their body weight (Holechek et al.1989). Cows may be able to compensate for lower-quality forage for a short time by increasing intakeand/or selecting plant parts higher in nutritionalquality than average plant parts. However, cows onseasonlong and deferred grazing systems lose weightfrom early or mid August to the end of the grazingseason (Manske et al. 1988). The loss of weight doesnot hurt the animals but does cause decreased milkproduction (Landblom 1989) and a subsequentreduction in the daily gain of calves (Manske 1996).

The negative effects suffered by plants on aseasonlong system with grazing begun too earlyinclude great reductions in herbage biomassproduction, which cause reductions in stocking ratesand animal production per acre. Data from threestudies indicate that if seasonlong grazing is started inmid May on native rangeland, 45-60% of thepotential peak herbage biomass will be lost and neverbe available for grazing livestock. If the starting dateof seasonlong grazing is deferred until early or midJuly, nearly all of the potential peak herbage biomasswill grow and be available to the grazing livestock,

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but the nutritional quality of the available forage willbe at or below the crude protein levels required by alactating cow. If the starting date is deferred untilafter mid July, less than peak herbage biomass will beavailable to grazing livestock because of senescenceand the translocation of cell material to belowgroundparts (Campbell 1952, Rogler et al. 1962, Manske1994a), and the crude protein levels of the availableforage will be insufficient to meet the nutritionalrequirements of a lactating cow.

The phenological growth stage of the grassplants is the best indicator of appropriate grazingstarting dates. Grazing plants before the third newleaf stage causes negative effects in grass growth,while starting grazing after the third new leaf stagestimulates tiller production, a process that leads toincreased aboveground herbage biomass andincreased nutritional quality of available herbage. Most native cool-season grasses reach the third newleaf stage around early June, and most native warm-season grasses reach the third new leaf stage aroundmid June. This phenological development indicatesthat within each management system, starting grazingon each pasture sometime between early June andearly July would produce the fewest negative effectson herbage biomass production and nutritional qualityof the available forage. Seasonlong grazingmanagement systems on native rangeland should waituntil mid June to begin grazing, but rotation grazingsystems could start in early June.

Continuation of grazing late in the seasoncan also produce detrimental effects on plants. Severe defoliation of grass plants during fall andwinter reduces herbage production of the grasslandsthe following growing season. Late-stimulated tillersremain viable over winter and continue growth thefollowing growing season. Cool-season speciesinitiate tillers the previous fall and continue growththe following season. Defoliation of late-stimulatedtillers and cool-season tillers during fall and winterreduces their contribution to the ecosystem thefollowing season.

The twice-over rotation system on nativerangeland with complementary domesticated grassspring and fall pastures times grazing to maximizevegetation and animal performance. A spring pastureof crested wheatgrass is grazed during May. Thetwice-over rotation grazing management system usesthree to six native rangeland pastures. Each of thepastures in the rotation is partially defoliated bygrazing for 7 to 17 days during the first period, the45-day interval from 1 June to 15 July when grassesare between the third new leaf stage and flowering

(anthesis) stage. The length in number of days of thefirst grazing period on each pasture is the samepercentage of 45 days as the percentage of the totalseason’s grazable forage each pasture contributes tothe complete system. During the second grazingperiod when lead tillers are maturing and defoliationby grazing is only moderately beneficial, after midJuly and before mid October, each pasture is grazedfor double the number of days it was grazed duringthe first period. A fall pasture of Altai wildrye isgrazed by cows and calves from mid October untilweaning in mid November.

The twice-over rotation system withcomplementary domesticated grass pastures has agrazing season of over 6.5 months, with the availableforage above, at, or only slightly below therequirements for a lactating cow for nearly the entiregrazing season. It requires fewer than 12 acres percow-calf pair for the entire 6.5-month grazing seasonon grassland that when grazed for 6.0 monthsseasonlong requires 24 acres per cow-calf pair. Thecow-calf weight performance on the twice-overrotation grazing system with complementarydomesticated grass pastures is improved over theperformance on other systems (Manske 1994b,Manske 1996).

It is possible that no range managementpractice can address all the problems inherent in anecosystem, but successful practices will incorporateadjustment for the most serious problems. The twice-over rotation system with complementarydomesticated grass pastures is one system that hasbeen shown to be well adapted to the conditions ofthe Northern Plains grasslands and to producepositive results in vegetation and animal performance. Acknowledgment

I am grateful to Amy M. Kraus forassistance in preparation of this manuscript. I amgrateful to Sheri Schneider for assistance inproduction of this manuscript.

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