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Graduate Student Theses, Dissertations, & Professional Papers Graduate School
1965
The distribution of plant communities in the Badlands of southeastern Montana
Raymond William Brown The University of Montana
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Recommended Citation Brown, Raymond William, "The distribution of plant communities in the Badlands of southeastern Montana" (1965). Graduate Student Theses, Dissertations, & Professional Papers. 6678. https://scholarworks.umt.edu/etd/6678
This Thesis is brought to you for free and open access by the Graduate School at ScholarWorks at University of Montana. It has been accepted for inclusion in Graduate Student Theses, Dissertations, & Professional Papers by an authorized administrator of ScholarWorks at University of Montana. For more information, please contact [email protected]. THE DISTRIBUTION OF PUNT COIMJNITIES IN THE
BADLANDS OF SOUTHEASTERN MONTANA
by
RAYMOND WILLIAM BRCWN, JR.
BoS.F. Montana State University, I 963
Presented in partial fulfillm ent of the requirements for the
degree of Master of Science in Forestry
MONTANA STATE UNIVERSITY
1965
Approved by:
Chairman, Board of Examiners
Dean, Graduate School
MAY 2 1 1965 Date UMI Number: EP37479
All rights reserved
INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted.
In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion.
UMT Dissertation Publishing
UMI EP37479 Published by ProQuest LLC (2013). Copyright in the Dissertation held by the Author. Microform Edition © ProQuest LLC. All rights reserved. This work is protected against unauthorized copying under Title 17, United States Code
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ProQuest LLC. 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 48106 -1346 ACKNOWLEDGMENTS
The Turiter wishes to express his appreciation to Dr. Arnold W.
Belle, Dean of the School of Forestry, for the financial support pro v id e d .
To my advisor and committee chairman. Professor Melvin S, Morris,
I wish to extend a special note of appreciation. I am sincerely grateful for having had the opportunity of receiving the benefit of his very
stimulating instruction and discussions throughout my undergraduate and
graduate career. For his most helpful suggestions throughout this study,
including the study outline, field work, laboratory analysis, and the preparation of the manuscript I am deeply appreciative.
Appreciation is extended to the members of the examining committee,
Professor Melvin S, Morris, Dr. Thomas J, Nimlos, Dr. James R, Habeck,
and Mr. J. E. Schmautz,for reviewing the manuscript and their many help
ful suggestions.
To my fellow students, Messrs. Harold Hunter and Laurance Rutagum- irwa, I express my appreciation for their help and suggestions with the field work.
This study would not have been possible without the cooperation of the personnel of the U, S, Forest Service. To Mr, R. C. McConnell of the Regional Office in Missoula, the writer expresses his sincere appreciation for reviewing the manuscript and many helpful suggestions.
To the personnel of the supervisor* s office of the Custer National
Forest in Billings, and particularly to Clarence Alman, the author's gratitude is given for suggestions and encouragement offered. A special note of appreciation is extended to the personnel of the Fort Howes and - i - -11 -
Ashland district offices, particularly Messrs, G, H, Nelson and
E. E, Bloedel for helpful suggestions and the loan of equipment and living quarters during the field work phase of the study.
Special thanks is extended to Dr, William R, Berg, Soil Scientist,
U. S, Forest Service, for his helpful instruction regarding the soils
and geology of the study area.
To my parents, Mr, and Mrs. R, W. Brown, I am sincerely grateful
for their generosity and willing assistance,
I am particularly grateful to my wife, Carole, for her continuous
encouragement and admirable patience during the course of this study. TABLE OF CONTENTS
Page
INTRODUCTim...... 1
LITERATURE REVIEW...... h
Recognition and Classification of Plant Communities, i;
Edaphic Effects on Plant Distribution ...... 8
Physiographic Effects on Plant Distribution ...... l5
DESCRIPTION OF THE STUDf AREA...... 21
L o c atio n ...... * ...... 21
G eology ...... 21
Drainage and Relief ...... 23
Vegetation and Soils, ...... 25
C lim ate...... 28
METHODS AND PROCEDURES...... 32
Vegetation Studies...... 32
Soil and Physiographic S tu d ies,,.,.,,..,...... Ul
FIELD AND IABORATORÏ RESULTS...... liU
Botanical Composition of Community-Types...... hS
Community Life-Form ...... U6
Relative Size and Area of the Community-Types...... h9
Species Composition of the Community-Types,...... 50
Shrub vegetation,,...... 53
Tree vegetation...... 56
Grass and grasslike vegetation...... 58
Forb vegetation ...... 6 l
Badland Microcommunities...... 62
- i i i - - i v -
Page
Dominant Species D istribution ...... 63
Dominant species variation among community-types.., 63
Dominant species variation within community-types.. 66
Edaphic Influences and Community Distribution, 68
Soil Physical Properties ...... 71
Soil texture ...... 71
Percent coarse fragments,...... 73
Permanent wilting percentage...... ih
Soil Chemical Properties...... 76
Soil reaction ,,, ...... ?6
Soil conductivity,,,..,,...... 77
Extract able sodium and calcium,,,,,,,,,,, ...... 78
Soil Morphological Features...... 80
Physiographic Influences and Community D istribution, ...... 82
Effects of Degree of S lo p e,,,.,,..,...... 83
Effects of Exposure ...... 88
Effects of Position on Slope...... 90
DISCUSSION...... 97
SUMMARY" AND CCKCLUSIONS...... 112
LITERATURE CITED...... 118
APPENDIX...... 126
I, lis t of the plant species found in the badlands of southeastern Montana,, ...... 12?
II, Summary of the number of feet of line intercept and soil samples collected by location ...... 130 -•V—
Page
I I I # Summary of th e frequency and abundance d ata fo r th e Sarcobatus community-type ...... 132
IV . Summary of th e frequency and abundance d a ta fo r the Atriplex-Artemisia community-type...... 133
V, Summary of the frequency and abundance data for the Artemisia-Atriplex-Agropyron community-type...... 13ii
VI. Summary of the frequency and abundance data for the Artemisia-Agropyron community-type ...... 13$
VII. Summary of the frequency and abundance data for the Rhus- Agropyron...... 136
VIII. Summary of the frequency and abundance data for the Juniperus-Agropyron community-type...... 138
IX. Summary of the frequency and abundance data for the Juniperus-Oryzopsis community-type...... liiO
X. Summary of the frequency and abundance data for the Pinus-Jurdperus community-type...... l l |l
XT. Soil profile descriptions for each community-type...... li|.2
XII, A summary of the environmental characteristics of each c ommuni ty -ty p e ...... LIST OF TABLES
Page
1. Summary of the relative area occupied by each community- type in the badlands,...... 50
2 . Summary of th e c h i-sq u a re a n a ly s is of dom inant sp e c ie s abundance variation between community-types ...... 65
3. Summary of the chi-square analysis of the variation in the abundance between major species w ithin c ommuni ty-typ es ...... 6? li. Summary of the soil characteristics of the upper and lower horizons for each community-type ...... 70
5. Summary of the soil characteristics of the two major badland microcommunities studied...... 82
-VI- LIST OF FIGURES
Page
1, Map of Montana showing the location of the study area and the Fort Union formation, .• * ...... 22
2, Average monthly precipitation for Ashland Ranger Station (elevation 2960 feet), and the former Fletcher Ranch 17 miles south of Ashland (elevation 3900 feet) for the p e rio d 19140-19Ü7 ...... 30
3, Close up view of a representative Sarcobatus community...... 3h
k* Close up view of a Atriplex-Artemisia community...... 3h
5. Close up view of a Artemisia-Atriplex-Agropyron community..... 35
6. Close up view of a Artemisia-Agropyron community...... 35
7. Close up view of a Rhus-Agropyron community...... 36
8. Close up view of a Juniperus-Agropyron community...... 36
9. Close up view of a Pinus-Juniperus community...... 37
10. The stick-line intercept sampling technique. * 37
11. Map of the Ashland Division of the Custer National Forest showing sampling locations and major drainages...... 39
12. A sketch of the sample line positions in a hypothetical community ...... UO
13. Summary of the abundance of forbs, grasses, shrubs, and trees for each community-type ...... U7 lii. Summary of th e abundance of th e m ajor sp ecies fo r each community-type, ...... 5 l
15. Summary of the physiographic characteristics in terms of slope percent and exposure for each community-type...... 8I|.
16 . A close up view of a clay bench on the slope contour support ing a dense stand of A triplex confertifolia, Artemisia tridentata, and Agropyron spicatum...... 87
17. A view of the general appearance of the parallel bands of vegetation on the contour of the slope supported by the clay benches ...... 87
—vi i — - V l l l -
Page
18# A profile of a south exposure near the mouth of Taylor Creek showing the position of some plant communities relative to slope and geological materials ...... 92
19# A profile of a south exposure near the mouth of Bloom Greek showing the position of some plant communities relative to slope and geological materials ...... 93
20, A profile of a south exposure near the mouth of 0*Dell Creek showing the position of some plant communities relative to slope and geological m aterials, ...... 9ii
21, A diagrammatic representation of the arrangement of each community-type on a badland slope ...... 95 INTRODUCTION
In a geographical sense southeastern Montana is related to the mid-continental Great Plains of North America, Vast areas of grassland vegetation, primarily composed of mid and short grass species of the mixed-grass prairie dominate the general landscape. Although these observations might suggest a degree of relative homogeneity in the vegetation, a close examination of the topography will show that a wide variety of habitats are provided in southeastern Montana, Soil and physiographic conditions vary sufficiently to suggest that an extensive array of many plant communities may be characteristic to this locality*
Under natural conditions various factors of the environment are responsible for the maintenance of productive native vegetation. How ever, since the introduction of domestic livestock grazing on the Great
Plains, many changes in the composition of the vegetation have occurred
(Reed and Peterson I 96 I ) , I t i s w e ll known th a t overgrazing im p airs th e productivity of the native vegetation and creates a situation for pos sible invasion by undesirable species (Reed and Peterson 1961, Arnold e t a l , I 96I4.). Although the dominant species are primarily composed of mid-grasses, increases in short grass species have occurred in some areas as a result of mismanagement and disturbance.
Guides to proper resource use are important particularly to assure full use of the resource without damage or loss. The range ecologist is interested in determining and understanding the relationships between the environment and vegetation for the purpose of making meaningful land management interpretations. An understanding of the soil and physio graphic and plant distribution relationships as well as the influence of
-1 - -2 - grazing is essential to making these management interpretations.
Through soi1-plant relationship studies various guidelines and objec tives for management can be formulated based on the capabilities and limitations of the area to support vegetation*
The author has had an unusual opportunity to participate in such a soil-plant relationship study cooperatively conducted by Montana State
University and the U.S. Forest Service* The general intent of this cooperative study is to provide a sound ecological basis for resource management of the native grassland vegetation of southeastern Montana,
Of particular interest to the author is the striking badland topography and its vegetation in this locality. This landform sup ports a sparse cover of xeric vegetation which present some difficult problems to the land manager. This complex vegetation type is classi fied as unusable or of limited value in terms of current management practices. There have been no previous attempts to study the soil- plant relationships of the badlands of southeastern Montana, conse quently little is known about the natural complexities of this type confronting the land manager. While these complexities involve a sparse vegetation cover coupled with extremely steep south facing slopes and a high soil erosion potential, little else is known.
Some readily distinguishable plant communities are arranged in a pattern composing the badland vegetation of southeastern Montana. It is suggested that these plant communities are regularly occurring elements, each significantly different from the others in terms of dom inant species abundance and soil and physiographic conditions. Each kind of community can be identified with rather specific edaphic and -3 - physiographic environmental conditions. The degree of dissim ilarity among th e v ario u s p la n t communities may be a ttr ib u te d to th e se s p e c ific environmental conditions.
These observations form the basis of a hypothesis concerning the environment-plant relationships of the badlands of southeastern Montana,
The specific objectives of the study are twofold: first, to determine if the various kinds of plant communities are significantly different in terms of the abundance of the dominant species; and second, to determine the influence of various physical, chemical, and morphological features of the soil and the physiographic conditions of the area on the distri bution of these plant communities. It is hoped that the results of this study w ill assist in establishing adequate guidelines for the effective management of the badlands of southeastern Montana. LITERATURE REVIEW
Recognition and Classification of Plant Comnmnities
It has long been recognized that it is possible to identify and describe natural groupings of plant species. These natural groupings or associations of species usually exhibit a characteristic physiognomy in a particular habitat. Natural aggregations of different plant species displaying uniform physiognomic characteristics are recognized as plant communities. The degree of uniformity in composition exhibited by the community, and its reoccurrence on different areas are related to the uniformity of, and interactions between the various environmental factors of the habitat.
The distribution of vegetation is a product of a complex of inter actions between all factors of the environment. The genetically pre determined physiological tolerance limits of each species is different
(Mason 19U6), Consequently, a given species of plant has a somewhat different ecological amplitude from all other species (Hanson 19^8,
Gleason 1939). Similarly, each habitat is different from all others and, as such, the vegetation in any two habitats is never identical
(Hanson 19^8, Gleason 1939). However, the amplitude of physiological limits overlap among species, with the result that species aggregation occurs in many habitats.
Although natural aggregations of species on similar habitats are never identical in terms of composition, they may resemble one another sufficiently to be recognized as one kind of community or community- type (Hanson 19^8, Hanson and Churchill 1961), The inclusion of -S- sim ilar communities into one community-type is most useful in the inter pretation of the relations between vegetation and environment (Hanson
1958)* Although habitats on various physiographic units tend to exhibit more or less pronounced environmental uniformity, the implication is not to be made that they exhibit absolute uniformity (Nichols 1923b).
Carpenter (1936) feels that local changes due to environmental factors may be common, y e t on th e whole th e same b io tic e n tity i s p re s e n t on similar habitats.
Gleason (1939) stresses that on any habitat the physical, chemical, and biotic factors vary in time and space, hence the vegetation varies.
He feels that logical and precise classification of communities is not possible because no two communities have a genetic or dynamic connec tion. Gleason (1939) attributes this to the individualistic nature of species and the continuous variability of environment. Hanson (19^8) suggests that quantitative analysis of the intrinsic characteristics of the community is necessary for classification purposes. Stands showing the greatest number of similar characteristics in terms of species composition and habitat structure can be grouped together, Hanson
(1958) recognizes, however, that with this must go the realization that a certain amount of variation exists among all similar stands.
The area over which a community occurs is controlled in varying degrees by the climatic, edaphic, physiographic, and biotic factors of the environment (Hanson 1958, Carpenter 1936), Clements (1936) believes the climax community of every succession to be the express product of climate and, as such, is the best indicator of it. The climax vegeta tion constitutes the major unit of vegetation, and thus forms the basis -6 - of the natural classification of plant communities (Clements 1936,
Phillips 193^)* The concept of climax as expressed by Clements (1928,
193k) 1936) considers the climax vegetation as the final stage of succession in permanent equilibrium with environment. The ultimate cause of community stabilization is species dominance, embracing the ability of the characteristic life-form to produce a reaction sufficient to control the community (Clements 1936, Phillips 1935, Weaver and
Clements 1938)#
Beadle (1951) stresses the importance of recognizing that climatic boundaries cannot always be relied upon to consistently indicate the boundaries of vegetation and soils. Although Clements (1928, 193k,
1936 ) emphasized the influence of climate on vegetation development, he recognized the influence of local edaphic and physiographic factors.
The concepts of postclimax and preclimax (Clements 1936) are outgrowths of the recognition that edaphic and physiographic conditions are more significant environmental factors for affording habitats not wholly commensurable with the general framework of the climax.
In regions having a uniform climate over a wide area the chief differences in vegetation appear to be due to local influences of top ography and soils (Phillips 1935, Nichols 1923b), In some areas a vég
éta tional continuum may be recognized where boundaries between communities are obscure. However, abrupt and definable boundaries between kinds of communities are common where environmental factors change abruptly (Hanson 1958, Mason 19k6, Gates et al, 1956, Daubenmire
1952). Daubenmire (19?6) recognized and distinguished between climatic -7 — climax communities and those influenced primarily by edaphic factors.
Daubenmire (1952) has classified groups of species exhibiting ecological sim ilarity throughout a particular vegetational matrix as unions, the smallest structural unit of vegetation. Cooper (I96 I) recognized the importance of microenvironmental variation influencing pattern in ponderosa pine.
The classification of communities is apparently strongly influenced by local environmental control of vegetation, Poulton and Tisdale (I 96 I) discuss a quantitative method for the description and classification of range vegetation based on vegetative and edaphic features of habitat- types. Weaver (195^, 1963) states that the prairie is a closed climax community with no waves of emigration or immigration. He feels that the prairie is a stable mosaic grassland capable of resisting invasion due to an extensive mat of root development in the soil, Ellison (I96O) has found, however, that extensive grazing pressure on the tall-grass and the mixed-grass prairie precludes extended climax stability. Denudation of climax vegetation under extended disturbance can grossly alter the aspect and composition of the community (Albertson and Weaver 19k 6 ,
E llis o n i 960 , Ellison and Woolfoik 1937, Reed and Peterson I 96 I , Sampson
1959). The ultimate distinction between kinds of communities is based pri marily on species composition and physiognomic appearance, Driscoll
( 196k) delineated plant communities of a relict area in Oregon on the basis of vegetational life-form, Daubenmire (1952) classified the com munities of northern Idaho and adjacent Washington into 13 climax plant associations, each characterized by a particular combination of plant - 8 - unions* Coupland (1950^ I 96 I) used dominance, distribution of sub dominants, and basal cover in determining grassland communities„ Looman
( 1963 ) proposed a preliminary classification of the grassland communi ties in Saskatchewan based on characteristic combinations of species
(kensorts) which are easily recognized in the field, Hanson and Whitman
( 1938) classified the grassland types of western North Dakota into nine major types in terms of the chief species in each, Clements (1936) con sidered life-form distinction as the primary distinction between climaxes.
M orris ( I 9L6 ) has indicated that the classification of grasslands in Montana on an ecological basis is needed to facilitate sound economic u se .
Edaphic Effects on Plant Distribution
On extensive areas having a uniform topography and climate, varia tions in vegetation type are usually due to differences in soil condi tions (Weaver and Clements 1938, Nichols 1923b). Every plant is a product of the conditions under which it grows, and is thereby a measure of these conditions (Clements 1928). Although the effects of climate may be dominant in determining the climax life-form , local dominance and community structure of either stable or serai communities can be expres sions of edaphic factors (Clements 1928), Extensive ecological research in the area of soil-plant relationships has shown that soil influences can be a major factor contributing to the distribution of vegetation.
The presence or absence of a plant can often be useful relative to the detection of specific soil conditions. In this sense, plants can be classified as edaphic indicators in terms of their response to soil - 9 - characteristics (Clements 1928, Sampson 1939)* Clements (1928) and
Sampson (1939) point out that dominant species having the most exacting requirements are the most important indicators because they receive the full impact of the habitat. The most reliable indicators of soil condi tions are stable plant communities that have occupied a particular soil
over a long period of time (Shantz and Piemeisel 19i|0, Clements 1928),
Small restricted plant communities may be important indicators of
specific soil characters (Sampson 1939).
The particular significance of indicator plants is the advantage they offer in identifying habitats on the basis of vegetative appearance.
This phenomena greatly facilitates the recognition and evaluation of the relationships between plants and environment.
The distribution of species and plant communities has definitely been shown to be an expression of edaphic influences in many cases.
Anderson (19$6) has shown that a shift of dominance in grassland climax
corresponds with changes in soil series. Plant communities ranging
from postclimax to preclimax are expressions of soil characteristics
(Clements 1936, Anderson and Fly 1955^ Burbanck and Platt 1961;), Pat
terns of serai communities have been found to be controlled by edaphic factors in many cases (Judd 1939^ Hanson and Whitman 1938, 1937).
Although considerable overlapping of species on different soil types may occur, differences in species composition may indicate edaphic control (Passey and Hugie I 963 ). Clements (193U) believes that within a climax formation, the presence of a relic t community representing a dif ferent climax is an indication of climatic compensation by edaphic factors. The closed nature of the prairie association is largely a -1 0 - function of intimate interaction between native species and soils
(Weaver I96 I , 1963 ).
Although no one factor of the environment completely controls plant distribution, the influence of a single factor or group of factors may be important. It is generally accepted that isolating and analyzing individual factors of the environment separately achieves more progress in understanding environmental relations (Daubenmire 19^9).
The influence of soil texture has been widely investigated and found to have a significant effect on plant distribution (Crockett 196k^
Box 1961 , Driscoll I 96I1, Shantz and Piemeisel 19i|0, Nixon 196ii, Nixon and McMillan 1961;, Hanson and Whitman 1938). Coupland (19^0, 196 I ) attributed the distribution of the major grassland climaxes of Saskatch ewan to the influence of available soil moisture as reflected in soil texture. Wright and Wright (19W) found that in the major grassland types of south central Montana raesic species often occur in xeric climates as the result of the compensatory effects of soil texture*
Clements (1936) considered soil texture important in determining post climax and preclimax communities.
In some instances soil texture has no apparent role in controlling the distribution of plants. Pase ( 19S8) found that texture plays a minor part in limiting the distribution of Artemisia tridentata in western Montana. Textural differences do not appear to be significantly different in soils of the Artemisia tridentata and A triplex conf ertifolia associations of Nevada and eastern California (Billings 19i;9)* Jameson e t a l . ( 1962 ) could find no consistent differences in texture between kinds of communities on Fishtail Mesa in Arizona, -1 1 -
Perhaps the most important soil factor influencing plant distribu tion is the availability of soil moisture as influenced by other edaphic factors (Potter and Green 1961;, Coupland 1950, 1961, McMinn 1952, Dauben mire and Slipp 19l;3> Smoliak 1956, Daubenmire 1959^ Dix 1958, Ellison and
Wollfolk 1937f Albertson and Weaver 19L6). The role of matrix, gravita tional, and osmotic tensions on soil moisture availability has been dis cussed by Buckman and Brady ( i 960 ), and the U.S. Salinity Laboratory
Staff (1951).
Potter and Green (1961;) found that moisture penetration is deeper in coarse textured and rocky soils. It appears that the distribution of
Pinus ponder osa in western North Dakota is restricted to coarse soils where it can successfully compete with herbaceous vegetation. In the
Madison Range of Montana, Patten (I 963 ) concluded that the availability of moisture is directly controlled by soil texture and other physical factors. Many salt-desert climax species are strongly influenced by soil moisture availability (Gates et 1956, Fautin 19^6, Shantz and
Peimeisel I 9U0 ),
The soil moisture content at field capacity and the permanent wilting percentage have been widely investigated, A significant differ ence in field moisture capacity between salt-desert associations was found by Gates ^ (1956). No significant difference was found for permanent wilting percentage however, Patten (I963 ) found the permanent wilting percentage to be significantly different between vegetation types in the Madison Range of Montana,
According to Daubenmire (1959) no other single value of the soil tells so much about its ecological character as soil reaction. Soil —12— reaction appears to be an important soil factor contributing to plant distribution (Crockett 1961;, Stone 19Ui, Fireman and Hayward 19^2,
Rickard 196$). Fireman and Hayward (1952) found a soil reaction gradient of decreasing magnitude from the Sarcobatus vermiculatus.
Atriplex confertifolia, and the Artemisia tridentata communities of the
Escalante Desert of Utah, Rickard (1965) found that the presence of
Sarcobatus vermiculatus influences soil pH, Soil reaction was highest
immediately under and around individual plants, but decreased with
increasing distance from the plant. Kelley (1922) found that soil pH is generally higher on dry exposed slopes than on less exposed slopes.
There is apparently no consistent pH in Artemisia tridentata soils in western Montana (Pase 1958). Bolen (1961;) concluded that pH is of
little or no consequence to the location of plant communities of salt marshes in western Utah. Gates et al. (1956) found no reliable statis
tical difference in pH between the soils of the Artemisia tridentata,
A triplex confertifolia, A. n u ttallii, Eurotia lanata, and Sarcobatus vermiculatus communities on the salt-desert of Utah,
The influence of soluble soil salts on plant physiology and d istri bution has been widely investigated. The characteristics of saline soils and their classification are discussed by the U.S. Salinity Laboratory
Staff (195k). Extensive reviews concerning the effects of salinity on plants are presented by Hayward and Wadleigh (I9k9), Magistad (19k5), and Black (195V).
It is generally agreed that permanent wilting of plants occurs when the stresses on soil moisture approach 15 atmospheres (Fox 1957,
U.S. Salinity Laboratory Staff 195k, Richards 1957, Richards and Weaver -13-
19Ü3). However, many halophytes are capable of growing on saline soils with a salt content sufficient to exert up to 200 atmospheres of tension on the soil moisture (Magistad 19hëf Hayward and Wadleigh 19h9)»
There is some question as to the indicator value of many saline tolerant species. Under conditions of freedom from competition, it appears that some halophytes can be expected to be found in saline hab itats, However, under increased pressure from competition the more salt-tolerant species are largely restricted to saline soils. Many species, such as Sarcobatus vermiculatus and Atriplex confertifolia, have a very wide tolerance range to saline conditions (Hayward and Wad le ig h I 9L9), Shantz and Peimeisel (I 9U0 ) found Sarcobatus vermiculatus on both saline and nonsaline soils, and concluded that its indicator value for saline conditions is questionable.
The possibility that Sarcobatus vermiculatus may be a salt tolerant species, but not a salt requiring one, has been suggested by Hayward and
Wadleigh (19ii9). Salt concentration was found to be highest under plants of Sarcobatus vermiculatus, and lower under Atriplex confertifolia and Artemisia tridentata plants (Fireman and Hayward 19^2, Rickard 196^ ) ,
Gates et al. (19?6) concluded that Sarcobatus vermiculatus has a very wide tolerance range for salinity conditions, and is not by itself a reliable indicator of high salt concentrations.
Perhaps one of the most common, widespread, and variable halophytes is A triplex conf ertifolia. This shrub species is one of the most drought tolerant desert plants, able to survive physiological drought but not physical drought (Billings 19k9, Stewart et al. I 9U0 ), Billings (19^9) found that A triplex confertifolia is not a reliable indicator of salinity —lii—
in the shadscale zone of Nevada and eastern California. However, tissue
fluids from this plant were found to have osmotic pressures as high as
153 atmospheres (Hayward and Wadleigh 19k9). Usually A trip lex conferti
folia is found on salt concentrations lower than Sarcobatus vermiculatus
(G ates e t a l. 1956, Rickard 1965) » Where salt concentrations are very
high in the lower soil horizons, A triplex confertifolia is capable of
surviving, but is usually found on moderate saline to nonsaline soils in
the northern desert shrub biome of Utah (Fautin 19U6), Similar results
were found by Shantz and Piemeisel (19^0).
The upper tolerance lim it of salt concentration of Artemisia tri
dentata has been reported to be about 1000 ppm. (Stewart et 19l|0).
However, Pase (1958) reported Artemisia tridentata in western Montana
occasionally occurs in salt concentrations as high as 6600 ppm. Under
the most usual circumstances this species is not an indicator of high
salt conditions (Gates et al. 1956, Fautin 19^6). Shantz and Piemeisel
(I 9I1O) reported it as a common associate of Sarcobatus vermiculatus on
nonsaline soils.
Mineral composition of soils has generally shown little or no sig
nificant influence on plant distribution. In most cases of positive
influence, the cause has been the over-abundance of certain cations such
as sodium, rather than a fertility deficit (Magistad 19U5). However,
W hite ( 1961 ) concluded that the distribution of Andropogon scoparius on
microridges in South Dakota was controlled by soil fertility . Nixon
(I 96L) reports that the distribution of Lupinus texensis is largely
restricted due to nitrogen and calcium deficiencies in soil.
Gates et al, (1956) conducted extensive soil chemical analyses of -1 5 - the soils of five consociations in the salt-desert of Utah, Their analyses have shown that there is no significant statistical difference among the various vegetation types for exchangeable sodium, base exchange capacity, exchangeable potassium, percent lime, and soluble sodium, calcium, magnesium, potassium, chlorides, sulfate, carbonates, and bicarbonates. Fireman and Hayward (1952), Hayward and Wadleigh
(I 9U9) and Rickard (1965) have found Sarcobatus vermiculatus to be very tolerant of high exchangeable sodium contents, but its distribution to be indifferent to it. A triplex confertifolia is moderately tolerant of high exchangeable sodium contents (Gates ^ a l, 1956, Hayward and Wad leigh 191:9).
Physiographic Effects on Plant Distribution
The primary physiographic effects on plant distribution are directly expressed in terms of moisture relations, as indirectly influ enced by exposure, slope, and position on the slope (Nichols 1923a, Dix
1958). Exposure affects the amount of solar insolation reaching the ground surface expressed in terms of heat energy and effects of drying.
The degree of slope is also related to moisture conditions and solar insolation intensity. The particular position on the slope occupied by a plant is significant from the standpoint of moisture runoff.
In areas of rugged relief, topogr^hic conditions, through their influence on moisture relations, seem to be of the greatest ecological importance (Nichols 1923b), It is apparent that in the Northern Hemi sphere north exposures usually provide more mesic habitats than south exposures, Cottle (1932) explains that the relatively xeric vegetation -1 6 - on south exposures differs from the mesic communities on north facing slopes primarily as a function of available soil moisture. Daubenmire and Slipp (19U3) attributed the differences in vegetation on north and south exposures as being one of water balance.
Although precipitation may be equal on all exposures of an area, higher wind velocities coupled with greater insolation received, tran spiration, and evaporation may account for the more xeric vegetation occurring on south slopes (Daubenmire and Slipp 19^3, Patten 1963 , Webb
I 96U). A significant difference between north and south slopes was found for soil moisture content, soil temperature, air temperature and vapor pressure deficit by Ayyad and Dix (196k). Their study of the vegetation-microenvironmental complex of the prairie slopes of
Saskatchewan indicated that for the nine different exposures studied, soil moisture and heat regimes of the soil layers controlled the dis tribution of vegetation,
Ayyad and Dix ( 196k) found the greatest difference in micro- climatic elements to be between north-north-east and south-south-west exposures. They feel that the greatest differences are not between north and south slopes because of the moderating effects of moisture,
A large part of the forenoon moisture in the soil and vegetation is dissipated by evaporation on east slopes in the morning. By afternoon the soil surface is comparatively dry before the maximum solar radiation reaches the south-west slopes. By the time solar insolation is directly received, the plants have lost turgor, and the energy received is applied largely toward an increase in temperature.
The relationship between vegetation distribution and exposure was -1 7 -
found to be more apparent than that with elevation in the Madison Range
of Montana (Patten 1963). Patten (I 963 ) found grasslands on all expo
sures. However, Pase (1958) found that this species was normally con
fined to north slopes and swales throughout its range in western
Montana. Where grazing had reduced the degree of competition with
grasses, Artemisia tridentata was found on the more xeric south slopes.
The basal area of woody species was found to increase over that of
herbaceous species on north exposures on the Wichita Mountains W ildlife
Refuge in Oklahoma (Buck 196i|). Herbaceous vegetation reached its
greatest basal area on south, east, and west exposures. Gumming (1953)
found similar results for the range vegetation in the desert grasslands
and oak woodlands of Arizona.
Coupland (1950, I 961 ) has indicated that there is a strong effect
of topography on plant succession in the grasslands of the northern
Great Plains. Exposure acts as a compensatory mechanism to relict
stands during periods of climatic shift. Exposure also provides
numerous habitats capable of supporting postclimax or preclimax com
munities within the climax formation (Clements 1928, 193U)* Clements
(I 93U) classified relict vegetation into two classes based on the com
pensatory features afforded by exposure. Mesoclines occur on cool moist
slopes, and represent the postclimax, while the xerocline represents the
preclimax community on warm, dry slopes.
In the subalpine zone of the Wasatch Plateau of Utah, Ellison
(195U) considered topography to be of greater importance to the d istri bution of vegetation than soils or parent materials, A striking feature
of the primary succession of the vegetation is the invasion by trees and -1 8 - shrabs on talus slopes and colluvium deposits on north exposures, regardless of the degree of slope (Ellison 195^).
The degree of slope reflects soil moisture conditions and solar insolation, and is intricately related to slope exposure. In the Little
Missouri Badlands of North Dakota, Dix (1958) found close sim ilarities in the vegetation on opposing east and west exposures where the degree of slope was sim ilar. Although east slopes might be considered less xeric, a greater comparative degree of slope may render its habitat more xeric (Dix 1958), Sampson (1939) indicates that species restricted to particular slope angles may be significant indicators of moisture con d itio n s .
Ellison (195U) felt that for a given stage in the landform cycle, a gentle slope is ordinarily older and more stable than steeper slopes.
He found that increased soil stability on gentle slopes supported herb communities which he considered successionally more advanced than shrubland and forest types. On talus slopes in northern Idaho, Dauben mire and Slipp (19^3) found that stability of the talus material is a prerequisite to climax development,
A close correlation between steepness of slope and vegetation types was observed by Patten (1963). Three successional forest types,
Pinus contorta , P. contorta-Picea-Abies, and Picea-Abies occur predom inately on slopes seldom over 30 degrees. Pseudotsuga menziesii was often found on slopes over 30 degrees. Permanent plant colonization on steep rockslides was lacking because steepness of slope prevented vege tative stabilization (Patten I 963 ). Shantz and Piemeisel (I 9U0 ) found that degree of slope is the principal factor separating the Artemisia -1 9 - and Jnniperus associations of the Escalante Valley in Utah, Where slopes are very steep, excessive water runoff, landslides, and earth- flows inhibit vegetation stabilization (Patten 1963, Dix 1958).
On the scoria and clay buttes of western North Dakota, degree of slope largely controls the stage of plant succession (Whitman and
Hanson 1939). Steep slopes up to 6o degrees support scattered plants of Artemisia tridentata, Atriplex confertifolia, Sarcobatus vermicu- latus, and other shrubs, while less steep slopes support stands of bunchgrasses and represent a later stage of succession.
The degree of slope is influential in determining the distribution
of salt-desert plants (Stewart et al, 19kO, Shantz and Piemeisel I 9L0,
F a u tin I 9L6 ), Stewart et (I 9U0) found that on dry slopes the soluble salt concentration increases with depth below the soil surface.
On flat playas the highest salt concentration is at the soil surface.
The more saline tolerant species are confined to the bottomlands, while the bunchgrasses and Juniperus stands occur on nonsaline upland soils.
Shrubs that are tolerant of moderate saline conditions are the most important competitors with grasses on the upland soils.
The habitat at various elevations on the same slope may differ for many reasons. One of the most important factors affecting habitat slope-position is the amount of water received or lost by runoff. Upper slope positions may be exposed to greater wind velocities (Weaver and
Clements 1936), and greater water drainage (Ayyad and Dix I 96 U). Differ ences in vegetative cover on the slope affect the heat and moisture balance near the soil surface (Ayyad and Dix I 96L).
Dix (1958) found that lower positions on slopes are areas of both -2 0 - deposition and erosion as the result of water runoff from steeper slopes above. Where runoff enters lower slope surfaces at a rate too fast to permit infiltration, high erosion damage and silting may result.
Ayyad and Dix (I 96U) found that soil temperatures on upper and middle positions are warmer than lower ones. Air temperature and vapor pressure deficit did not vary significantly from one position to another. Variations in soil moisture content proved to be significant in most instances. They found gradual consistent increases in soil moisture from upper to lower positions. For this reason lower positions usually support a denser vegetation than upper positions (Ayyad and Dix
I 96 U). DESCRIPTION OF THE STUDT AREA
L o cation
The area selected for study is on the Ashland Division of the
Custer National Forest in southeastern Montana. The study area occupies portions of western Powder River and southeastern Rosebud counties, and lies approximately 130 miles east of Billings, and 30 miles west of
Broadus, Montana, The area encompasses about hhS,000 acres within the
National Forest boundary, and of this about 2^,000 acres are privately owned.
Figure 1 is a map of Montana showing the location of the study a re a .
Geology
Most of the surface geology of eastern Montana belongs to the Fort
Union formation. The Ashland Division and most of the surrounding country belong to the Tongue River member of the Fort Union formation
(Warren 19^9). The geological material of this formation is of Paleo- cene age, having been deposited by fresh water streams originating from mountain sources to the west (Warren 1959). These sediments originated in the North American central cordilleran and were deposited following the up-lift of the Rocky Mountains during the lower Cretaceous period
(Schuchert and Dunbar 19L5).
The contact between the Fort Union formation above, and the dino saur fossil-containing Laramie sediments below is considered the sepa ration between the Cretaceous period and the Paleocene epoch of
—21— —22«"
Figure 1. Map of Montana showing the location of the study area and the Fort Union Formation,
£ frrr
y
4> m H 0 a H o •H m % —23*"
geological time (Schuchert and Dunbar 19hS)» The Fort Union sediments
contain fossils of eastern broadleafed deciduous flora and shells of
mollusks, but do not contain dinosaur fossils (Warren 1959). Petrified
logs and leaf imprints of broadleaf vegetation are abundant throughout
the study area.
The weakly consolidated sedimentary rocks of the study area consist
of nearly level beds of sandstone, silty sandstone, clay shales, and
lignite. The many lenses of lignite indicate that shallow brackish seas
were present at different intervals of time during the Paleocene epoch
(Schuchert and Dunbar 19L5). Where extensive beds of lignite have
burned, adjacent shale strata have been baked resulting in a reddish
iron-oxide colored porcellanite material (Warren 1959). Locally this
reddish porcellanite is called scoria or clinker.
Alluvium deposits of Quaternary age compose the stream and river
valleys. Terraces of primary drainages are composed of sands and
gravels of igneous origin, while the alluvium deposits of secondary
drainages are composed of porcellanite and sandstone (Warren 1959).
Drainage and Relief
Drainage of the study area is accomplished primarily by the Tongue
and Powder Rivers, which are located on the west and east boundaries of
the Ashland Division, The principal drainage within the study area is
Otter Creek, which flows from the south and drains into the Tongue River
to the north. The many tributaries of Otter Creek are oriented in east- west directions, leaving south and north facing slopes dominant in the
study area. The primary drainages run water throughout the year, while secondary drainages and their tribataries run water only during periods o f snowmelt or fo llo w in g high i n t e n s i t y summer sto rm s.
Most of the major streams within the study area are slow running and widely meandering. The principal drainage channels are usually broad valleys up to one-half mile wide, with old stream levels well defined as terraces above the present flood plain.
Most of southeastern Montana, Including the Ashland Division, is a portion of an extensive intricately dissected unglaciated plateau.
Narrow ridges and gently rolling topography are all that remain of the plateau in the northern portion of the study area. In the central and southern portions steep south-sloped surfaces exposing colorful geologi cal strata are common. In some places these exposed surfaces are found on west and east facing exposures where the slopes are very steep. The varying degrees of resistance to erosion of the various strata are dis played as a series of upland benches in some places. North exposures are usually less steep with more uniform slopes.
The maximum relief of the study area is about lUOO feet, ranging from 3000 to kkOO feet in elevation. On the steep rugged breaks of the major drainages relief of 500 feet or more may occur within distances of one-fourth mile or less.
The badland topography of the study area is composed of outcrops of shale and sandstone on steep slopes. Nearly level strata of interbedded shales of blue-gray to gray clay and buff-colored silt beds varying in thickness from a few inches to several feet are exposed on steep south slopes. These strata alternate with each other, with occasional beds of lignite coal separating the lenses of clay and silt. At various levels -2 5 -
massive outcroppings of sandstone and siltstone are exposed, often
exceeding 30 feet in thickness.
The general landform of the badlands displays several distinctive
topographical features. In some places the badland topography grades
into broad rolling upland benches where the shale slopes are capped
with porcellanite. Where the porcellanite beds have been eroded away,
or where they were never formed, the general badland topography takes on
a butte or mesa-like appearance. The mesa-like landform takes on the
appearance of a flat table-top capped with massive sandstone, while the
buttes have an irregularly defined top as the result of differentially
eroded clay shales and s ilt beds. In some places remnants of badlands
remain as cone-shaped knolls or as massive sandstone pillars and irregu
lar pillars. There is some indication that porcellanite-capped cones
are more resistant to erosion, and persist for longer periods of geolog
i c a l time*
Vegetation and Soils
The gently rolling upland benches above the badlands and drainage
terraces below, are composed primarily of mid-grass vegetation. The
principal species include stands of Agropyron sm ithii, Stipa viridula,
S. comata , and Festuca idahoensis. On north slopes below the upland
benches the principal vegetation is composed of Pinus ponderosa stands,
with some localized pockets of Juniperus scorpulorum. Pine woodlands
grade into gently sloping stream terraces of grassland vegetation.
The diversity in environmental conditions of the badland topography provides a variety of plant communities mostly composed of shrubs and - 2 6 - bunchgrasses. On steep south slopes of scoria ridges Rhus trilobata is
the dominant species, with scattered Agropyron spicatum as the principle
subdominant. The steeper exposed surfaces of weathered shale are
sparsely covered with scattered stands of mixed A triplex conf ertif olia
and Artemisia tridentata. On these steep surfaces the vegetation often
appears to occur in successive narrow parallel bands along the contour
of the slope (see Figure U), Talus slopes support a denser cover of
Artemisia tridentata, Atriplex confertifolia, and Agropyron spicatum.
Stands of Sarcobatus vermiculatus are common where high concentra
tions of salts accumulate on the soil surface, Sarcobatus vermiculatus
communities are most common on lower slopes and fla t areas, but may be
found on talus slopes or steep surfaces of exposed strata as well.
The deeper side drainages of the badland slopes support stands of
Pinus ponderosa and Juniperus scopulorum. Adjacent to the grassland
vegetation of the drainage terraces colluvium deposits from steep
slopes above and knob-like remnants of sandstone outcrops and columns
support scattered stands of pine and juniper. Scattered patches of
Pinus ponder os a on sandstone caps rimming the tops of buttes and mesas
a re common,
A species list of all of the plants found on the badlands of south
eastern Montana is included in Appendix 1,
The geologic materials of the study area are the principal parent
materials of the developed soils. The relationships between parent
materials and soils are reflected in terms of the amount of sand, silt,
and clay present. The dominant soil textures are silt loams and clay
loams, with some localized areas of sandy loams near sandstone outcrops. -2 7 -
Soil development is principally a feature of upland benches and drainage terraces supporting grasses, and moderate north slopes support ing Pinus ponderosa and Juniperus scopulorum woodland. These soils are primarily of the Chestnut, Brown, Regosal, Lithosol, and Solodized
Solonetz great soil groups. Some of the mois ter forested soils in some areas are of the Gray Wooded great soil group.
Soil development is not a feature of the badland topography how ever, although restricted areas of shallow soils and Lithosols may be found in some localized areas. For the most part exposed geologic material and mixed colluvium are the principal soil materials of this landform. The limited soil development that has occurred is on the gentler talus slopes and on localized benches shallowly underlain by san d sto n e.
Talus material tends to accumulate on benches, gentle slopes, and at the bases of steep south slopes of the badland landform. This material is primarily colluvial, ranging in depth from a few inches to several feet, and is composed of weathered fragments of sandstone, silt- stone, clay shale, and procellanite. Detached fragments of sandstone and siltstone flag material ranging in size from several inches to several feet in diameter are common constituents of these talus slopes.
On moderately steep slopes colluvium accumulates to depths of about one or two feet. On the toes of the steeper south slopes mounds of collu vium accumulate to greater depths of large sandstone and siltstone fra g m e n ts,
During the course of the soil survey conducted by the U. S. Forest
Service on the Ashland Division, soils were grouped geographically into -2 8 -
soil management areas. The badland topography was grouped into a single
s o i l management a re a r e f e r r e d to by th e s o i l s c i e n t i s t as th e Midway
shale outcrop. In general, the terms badland and shale outcrop can be
used interchangeably to mean the same topographic landform. Approxi
mately 8^,000 acres of this landform have been mapped on national forest
la n d .
The main big game species present include mule deer and antelope.
Game birds include turkeys, pheasants, sage grouse, and sharptail
grouse. Other wildlife species include coyotes, prairie dogs, bobcats,
and racoons. Stabler (1939) has made some interesting observations
concerning the mammals of the badlands of South Dakota, On badland
buttes he found populations of the badland chipmunk, Osgood deer mouse,
pale bushy tailed woodrat, white-tailed jack rabbit, and Wyoming cotton
tail, He indicates that on butte slopes devoid of vegetation, there is
a strong pelage-soil color correlation between mammals and geological
m a te ria l.
C lim ate
The mid-continental position of the mixed prairie grassland is so
situated that it is subject to great variations in weather conditions
(Borchert 19^0, Coupland 19^8, Thornthwaite 19Ul)* The continental
nature of the climate of this region has been characterized as dry-
subhumid to semi arid, but every kind of climate from arid to humid has been recorded (Thornthwaite 19^1).
The climate of the study area has been described as having cold winters, warm summers, and great variations in seasonal precipitation -2 9 -
(Dightman I 963 ). Normally about three-fourths of the annual precipita tion is received during the months of April through September, with May and June being the wettest months. For the most part, the lower eleva tions (below about 3300 feet) receive about 12 to 13 inches of annual precipitation, while the upper elevations receive as much as 18 inches.
It appears that the precipitation data recorded at established weather stations are not entirely indicative of the rainfall received on the areas on which the study was made. Most of the weather stations are located at elevations below 3300 feet, whereas the study was con ducted mostly above this elevation. At the former Fletcher Ranch located 17 miles south of Ashland, and at an elevation of 3900 feet, the annual average precipitation was 18,96 inches for the years 19UO-19t7*
The average annual precipitation at the Ashland Ranger Station in the town of Ashland, located at an elevation of 29^0 feet, was 1^,25 inches for the same period. These data indicate that perhaps local topography has a significant effect on precipitation in this area. Also, these data indicate that the actual annual precipitation on the areas studied is probably over l5 inches.
The histograms in Figure 6 compare the average monthly precipita tion for the period 19iiO-19ii7 for these two areas.
The average annual snowfall is about 30 inches in the valleys, but is somewhat greater at higher elevations (Dightman 1963).
The average annual temperature is about degrees F., with aver ages for all elevations ranging between ii3oO and 1|6,5 degrees (Dightman
1963 ). Summers are usually warm with July being the warmest month. The
Ju ly maximums range between 85 and 95 degrees F . , and th e minimums k r-
3 Ashland Ranger Station (Average annual 14.25 inches)
? m 0 1111 o H* C+H- % H* § H*» Former Fletcher Ranch 5’ s* (Average Annual 18.96 inches) 0) U) 1111 ■ ■ Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec
Figure 2. Average monthly precipitation for Ashland Ranger Station (elevation 2960 feet), and the former Fletcher Ranch IT miles south of Ashland (elevation 3900 feet), for the period 1940-19^7 (U. 8. Weather Bureau 1952). -3 1 - usually above $0 d e g re e s.
The length of the growing season during the frost free period i s about 128 days at Broadus, but is about 10 to 15 days longer on th e hillsides to the west (Dightman 1963). The coldest days occui" in
January, with temperatures seldom below zero degrees F,
For the most part, the study area is not as cold in the winter or as hot in the summer as areas further north (Dightman I 963 ),
Southeastern Montana lies in the Alberta storm belt, and re c e iv e s a mean transport of continental air from the eastern slopes of th e Rocky
Mountains 12 months of the year (Borchert 1950, Coupland 1958, 1959).
Abnormally strong westerly circulation of dry air results in the persis tence of drought conditions across eastern Montana. Drought conditions for periods of up to 35 days can be expected annually in the n o rth e rn
Great Plains (Coupland 1958).
Occasionally storms of a severe nature cross over the study a re a , but high winds of up to 50 or 60 miles an hour and tornados are uncommon
(Dightman I 963 ). The most severe damaging storms are summer thunder storms often accompanied by hail and occasional flash flooding. METHODS M D rflOCEDURES
A total of seven different plant commvmity-types characterize the vegetation of the badlands of southeastern Montana. Each type of plant community is easily distinguished from the others in terms of the char acteristic dominant species present, and rather specific edaphic and physiographic conditions.
These seven plant community-types have been identified by name in terms of the dominant species or association of species occurring in each. These are the Sarcobatus, A triplex-Artemisia, Artemis ia-Atriplex-
Agropyron, Artemisia-Agropyron, Rhus-Agropyron, Juniperus-Agropyron, and
Pinus-Juniperus communities.
Figures 3, k, 6, 7, 8, and 9 are photographs showing close up views o f each of th e p la n t commun!ty -ty p e s .
An additional plant community-type, the Juniperus-Oryzopsis commun ity , not occurring on the badland topography, was studied. This commun ity is found only in localized areas on north exposures in relatively moist microenvironments. This community displayed a close degree of relationship to the Juniperus-Agropyron community, hence it was included in the study.
The field work was accomplished during the summers of 1963 and 196L.
Laboratory analyses of the data and samples were conducted during the f a l l o f I 96I1, and winter of 1965.
Vegetation Studies
The vegetation of the various plant communities was analyzed using the line intercept sampling method described by Canfield (19^1). To
- 32- -3 3 - facilitate the sampling procedure on the steep slopes of the badland topography, and to enable the author to carry on the work without the need of another man, a modified form of the standard line intercept methods was devised. The author has identified this modification as the
"stick-line intercept method,"
A straight light weight stick, 5-feet long, and graduated in inter vals of hundredths of a foot was held in a horizontal position, and intercept values were recorded along its margin. An extended pocket- tape was used as a plumb to aid in reading the intercept of plants where the stick was elevated above the ground level.
The stick-line intercept sampling technique is illustrated in use in Figure 10.
This modified line intercept method was used for all vegetation sampling in all the plant communities studied. Basal intercept of grasses and forbs, and crown intercept of shrubs and trees was recorded in each community.
Each kind of plant community was sampled in a number of widely scattered locations. Some difficulty was encountered in locating suitable sampling locations for the various communities, and several of the types were found to be much more abundant than others. Therefore, not all the communities were sampled at the same number of locations, or with the same amount of total intercept.
An a ttem p t was made to sample each community-type in as many scattered locations throughout the study area as possible. Normally a sampling location constituted the south slope along a drainage channel or butte, However, in most cases a sampling location included a 2 %
Figure 3, Close up view, of a representative Sarcobatus community.
mmrn
###L
Figure 1|, Close up view of a Atriplex-Artemisia community. -3^ -
Figure 5* Close up view of a Artemisia-Atriplex-Agropyron community.
y
Figure 6. Close up view of a Artemisia-Agropyron community. -3 6 -
Figure 7 . Close up view of a Rhus-Agropyron community.
Figure 8. Close up view of a Juniperus-Agropyron community. -3 7 -
Figure 9, Close ap view of a Pinas-Juniperus community,
Figure 10. The stick-line intercept sampling technique, —38— composite of slopes and exposures. These included primarily the south exposures at the mouths of major drainages and the east and west exposures where badland vegetation occurred. Slopes of isolated buttes and mesas were also included where suitable sampling conditions were found.
A map of the study area showing the major sampling locations and drainages is presented in Figure 11,
No single location was found at which all seven plant community- types occurred together. In most instances only one or a few of the types could be sampled at one location. This prevented the possibility of pairing all of the sampled communities.
Sampling was restricted to communities of sufficient size to allow a minimum of from 50 to 100 feet of straight intercept line to be run through them. Sample lines were located in the central area of the com munity, and care was taken not to sample near the community boundary.
Sample lines were laid parallel to the length of the slope, and the num ber of lines varied from one to several. Individual lines were kept about 2$ feet apart. The total number of feet of intercept collected at each sample location for each kind of community varied somewhat, with a minimum o f 50 f e e t re c o rd e d .
Slightly less than half the data were obtained by recording inter cept for every consecutive 5-foot interval on a sample line. It was later felt desirable to record intercept data for every other 5-foot interval. More than half of the vegetation information was collected in this manner. A sketch of the sample line positions within a hypo thetical community is presented in Figure 12, —39— C u ster Co. Powder River Co.
S c a le
M iles
Ashland
CK.
CK
Rosebud Co
Bighorn Co lEGEND Forest Boundary . — County Line — Drainage # Sampling Location ^ Fort Howes Ranger Station Figure 11. Map of the Ashland Division of the Custer National Forest showing sampling locations and major drainages. 4 tO -
A summary of the number of feet of intercept recorded by location, and the total intercept collected for each kind of plant community is presented in Appendix II,
Line intercept data were analyzed in terms of abundance and fre quency, Abundance information was expressed in terms of intercept per
F ig u re 12, A sketch of the sample line positions in a hypothetical community. slope direction
5-foot intercept line
5-foot interval between intercept lin e s
community boundary
100 feet of line for each species in each community. The calculation of frequency was made by determining the percent of the 5-foot segments on which each species was found to occur of the total segments taken. Fre quency data were obtained only fTom those locations on which every other
5-foot segment of line intercept was recorded,
A summary of the frequency and abundance data for each species encountered in each community-type is presented in Appendix III, IV, V, 4 i l -
VI, VII, VIII, IX, and X.
Chi-square analysis was used to test the difference of the abundance between the dominant species in each kind of plant community (Snedecor
19$6). Chi-square analysis was also used to determine if there was any significant difference between the abundance values of the same species occurring in different kinds of communities. This latter test was accomplished only for paired stands of different communities.
Booth ( 1950) was used in the identification of conifers and monocots other than grasses. Grass nomenclature follows Hitchcock (19$0).
Dicotyledons were identified according to Booth and Wright (I 962 .
Soil and Physiographic Studies
The design of the study involved the determination of various phys ical, chemical, and morphological features of the soil for each plant community-types studied. Soil samples were analyzed in duplicate for texture, reaction, percent coarse fragments, moisture retention, soluble salt content, and extractable sodium and calcium.
As used in this study, the word soil includes undeveloped geologi cal material as well as developed soil. This generality will be used throughout the text unless otherwise noted.
Soil profile descriptions were made in the field for each kind of plant community studied. This involved the visual determination of horizon depth, color (Minsell color chart), structure, textural class, and the presence of carbonates (Soil Survey Staff 19$l). In most cases a typical horizon sequence was not detected, but often some differences in the soil material were apparent. A general profile description for each type of community is included in Appendix XI.
Soil samples were collected from each community studied. Soil pits were dug near the center of each community, and the soil material from each horizon was placed in labeled paper bags, and brought back to
Missoula for analysis. In some instances soil samples were not col lected at every location sampled for vegetation composition. Additional soil samples were collected for some communities at localities not analyzed for vegetation composition,
A summary of the locations at which soil samples were collected is presented in Appendix II.
Soil samples were sieved through a 2 millimeter screen to separate the coarse fragments from soil material (Buckman and Brady 19&0, Soil
Survey Staff 19^1). The percent coarse fragments was visually estimated in terms of volume of the soil material plus the coarse fragments.
Texture analysis was completed by determining the percent sand, s ilt, and clay using the hydrometer method (Bouycoucos 1936).
Soil reaction was determined with the Beckman model H2 glass elec trode pH meter (Davis 19U3). A saturated soil paste was used in this analysis, prepared according to the method prescribed by the U.S.
Salinity Laboratory Staff (19Sh)•
A pressure membrane apparatus was used to determine the permanent wilting percentage for each sample (Richards 19U7). Soil moisture reten tion at a pressure of 15 atmospheres is considered to represent the moisture content at which plants w ill permanently w ilt (Richards and
Weaver 19U3)*
Electrical conductivity was determined for the purpose of evaluating —il 3“ the soluble salt content of each soil sample* A Solu-Bridge Soil Tester model RD-15, and an A.H, Thomas Conductivity Cell was used for this determination. Conductivity was determined using a saturated soil paste as described by the U.S. Salinity Laboratory Staff ( 19$i|)*
E x tra c ta b le sodium and calcium were determ ined u sin g th e Beckman model W flame emission spectrophotometer. Two and one-half gram samples of soil were washed in 100 m illiliters of ammonium acetate adjusted to a pH of 7.0 (Jackson 19^3). Nine standard concentrations ranging from 0 to 100 parts-per-m illion were used for both sodium and calcium to establish the calibration curves. The values in ppm for the soil samples were converted to milliequivalents per100 grams of soil for each cation.
The latter analysis was conducted for all soil samples except for those of the Rhus-Agropyron, Juniperus-Agropyron, Juniperus-Oryzopsis$ and Pinus-Juniperus communities. Only selected samples of the latter fo u r communities were an aly zed , A minimum o f 60 p e rc e n t of th e t o t a l number of soil sanples from these communities were used in this analysis.
At each sampling location in the field the percent slope was deter mined with an Abney level. Exposure was determined with a Silva compass corrected for declination, and position on the slope was estimated to the nearest one-third of the slope length. FIELD MD lABORATCEY RESULTS
Eight types of plant communities, referred to as community-types, have been studied in terms of botanical composition, and the effects of soils and physiographic factors on their distribution. Each community- type appears to have some rather distinct vegetative, edaphic, and physiogr^hic characteristics which will serve to differentiate it from the others. Field observations indicate that each community-type occurs only where the particular environmental conditions specific to it exist in proper combination. It is the intent here to recognize, isolate, and analyze the distinguishing botanical features and the most influential environmental factors of each community-type.
The various stands of each community-type were identified primarily on the basis of the relative abundance of the species present. In the field little difficulty was encountered in associating the stands with a community-type. Usually the dominant species imparted a very conspicuous structure to the community, and this allowed for stand identification wholly on the basis of the vegetation present. It was never found neces sary to base stand recognition on other community-type characteristics of soil factors, slope gradient, exposure, or position on the slope.
However, with increased fam iliarity with the various habitats, it was found that most stands could be identified on this basis.
Most of the information and data presented represent averages of many individual stands for each community-type. The values from a par ticular stand, or for a particular species of a stand could be expected to differ from the average. The assumption was made in the beginning of the study that the various stands of a community-type are sufficiently
-kk- - w - similar in terms of the dominant species present and their relative abundances that they can be arranged into the same vegetation type. It is the intent here to show only the average characteristics of each community-type, but realizing that variations in botanical composition and environmental factors do exist among stands of each type. The results of the analysis w ill show that variation within a community- type is no greater, and usually much less than variation among community-types.
Botanical Composition of Commun!ty-Types
Each plant community-type was analyzed in terms of species abun dance and frequency. In this case abundance is an expression of the amount of intercept per 100 feet of intercept line. Frequency data represents the number of 5-foot sample segments on which a species occurred expressed as a percent of the total segments examined.
Abundance information was gathered in all the stands of each community-type that were sampled. On the other hand, frequency data were collected only during the latter phase of the study, and represent about 60 percent of the stands studied. Also, for the purposes of this study, the quantitative measure of cover in terms of abundance is a more meaningful expression of community composition. Frequency is an expression of plant dispersion (Greig-Smith 1957), but it gives no quan titative measure of plant cover. Frequency information was included only in as much as it presents a measure of species dispersion,
A summary of the average species abundance and frequency for each plant community-type is presented in Appendices III through X, The stands of each community-type were sampled in various widely scattered locations. The table in Appendix II indicates the number of locations sampled for each community-type. The frequency and abundance data pre sented represent averages of the data from each stand sampled. Abundance data are expressed in hundredths of feet for each species, and are sum marized as to life-form class. The grand total abundance value represents the total ground cover in hundredths of feet per 100 feet of line inter c e p t.
Community Life-Form
Each of the eight kinds of plant communities has a characteristic appearance imparted by its vegetation. Even from some distance it is quite possible to identify the community-types solely on the basis of their physiognomic appearance. It seems instructive to analyze this characteristic of the plant communities in an attempt to understand their composition and structure. The various life-forms considered include forbs, grasses, shrubs, and trees.
Figure 13 is a summary of the total abundance of each of the life- form classes considered for each plant community-type.
Considering only the badland communities, and excluding the
Juniperus-Oryzopsis community, there appear to be two major groups of communities in terms of life-form . Five community-types, the Sarcobatus,
Atriplex-Artemisia, Artemisia-Atriplex-Agropyron, Artemisia-Agropyron, and the Rhus-Agropyr on are dominated by shrubby vegetation. The second group include the Juniperus-Agropyr on and the Pinus-Juniper us communi ties, dominated by tree vegetation.
Of the five shrub community-types, the Sarcobatus, Atriplex- I I Forbs Grasses Shrubs Trees
20 56.2 29.1
<£ I I 10 &—J Is 1 o
KN KN M P inus- S arcobatus I Atriplex- | Artemisia-1 Artemisia- Rhus- I Juniperus- jJuniperus- Art eraisia Atriplex- Agropyron Agropyron Agropyron Oryzopsis ’ Juniperus Agropyron
Figure 13. Summary of the abundance of forbs, grasses, shrubs, and trees for each community-type, - 1 8 -
Artemisia, and the Artemisia-Atriplex-Agropyron have a substantially higher abundance of shrub cover than the other two. Of these three, the
Artemisia-Atriplex-Agropyron has a greater grass abundance. The
Atriplex-Artemisia community is distinguished as having the least vege tative cover of the three, exhibiting a lower abundance of shrubs, grasses, and forbs. The Rhus -Agropyron community is distinguished from the Artemisia-Agropyron community in terms of the greater abundance of forbs and the presence of some trees, which are completely lacking in the latter.
The Juniperus-Agropyr on and the Pinus-Juniperus communities are easily distinguished in terms of the greater abundance of shrubs in the former, and of grasses in the latter. However, another point of consid eration in this regard is the difference in general appearance between the two dominant species, Pinus ponderosa is usually a much larger tree than Juniperus scopulorum, the pine often attaining heights in excess of
60 feet, and the juniper seldom over 1$ feet. The differences in foliage and crown shape are also important considerations.
Differences between the Juniperus-Agropyron and the Juniperus-
Oryzopsis communities are more subtle since both community-types are dominated by Juniperus scopulorum. In fact, the principal ecological difference between them is not physiognomic, but rather physiographic.
However, a striking feature of these two community-types is the differ ence in abundance of the dominant species. The Juniperus-Agropyron com munity supports from 300 to 600 juniper trees per acre, these seldom exceeding 10 or 12 feet in height. The Juniperus-Oryzopsis community, on the other hand, supports from 700 to 1$00 trees per acre, these *"U9“ frequently exceeding 12 feet in height.
Relative Size and Area of the Comrrmnlty-Types
The various plant communities at the various sampling locations varied in size from several hundred square feet to several acres* The size and area of a community are functions of the physical environment, and the environmental complex of the badlands is such that particular habitats are often absent from large areas of badland topography. There fore it was rather difficult to determine the relative area occupied by each kind of plant community-type.
Through field observations and with the aid of aerial photographs, an estimate was made as to the percent of the total area of the badland topography each community-type occupied. Sketches on paper or photo graphs were often used to determine the community composition at any one or group of locations. The percentage values in Table 1 represent gross estimates only, and the composition at any one or group of locations may vary significantly from those given.
In making these estimates care was taken to gather information from many w id ely s c a tte re d lo c a tio n s throughout th e stu d y a re a . Thus, some of the locations from which this information was gathered were not necessarily the same locations at which vegetative samples were col lected, The problems and sources of error encountered in making these estimates include the fact that all the plant community-types do not occur at every badland location. Thus, it can be expected that in some places certain community-types comprise $0 to 100 percent of the badland topography, and yet at other locations they may be very scarce or lacking —^0— altogether. Defining the typical condition relative to community composition has thus proven very difficult.
Table 1 , Summary of the relative area occupied by each
community-type in the badlands,
Community-Type Percent
Sarcobatus ...... 3
Atriplex-Artemisia...... 10
Artemisia-Atriplex-Agropyron ...... 30
Artemisia-Agropyron ...... 10
Rhus-Agropyron ...... 17
Juniperus-Agropyron ...... 20
Pinus- Juniperus ...... 10
Species Composition of the Community-Types
A summary of the abundance of the major species found in each c ommuni ty-type is presented in histogram form in Figure lU, The symbols used in the histogram indicate species names as follows: Agsp,, Agro pyron spicatum; Bocu,, Bouteloua cur tip endula; Bogr, ^ Bouteloua gracilis;
Orhy,, Oryzopsis hymenoides; Ormi,, Oryzopsis micrantha; A rtr,, Artemisia tridentata; Atco,, Atriplex confertifolia; Rhtr,, Rhus trilobata; Save,,
Sarcobatus vermiculatus; Jusc,, Juniperus scopulorum; Pipo,, Pinus p o n d ero sa.
The following discussion of each of the life-form classes of A; -5 1 - Figure li;, Summary of the abundance of the major species for each 10 c ommuni ty -ty p e *
S arcobatus
5 -
0 ■ji m n n q , 10 Atriplex-Artemisia
« a 8 u &
0> o06 a 0 S 10 •H Artemisia-Atriplex Agropyron o t £
0 .01 .07 10 Artemisia-Agropyron
.05 0 1— 1I------1 1 1 1 o Ü A a -p (0 & I I f I »? - 5 2 -
F ig u re 11;, Summary of the abundance of the major species for each 10 community-type - Continued,
Rhu 8-Agropyron / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / r r / ltO.2 TO Juniperus-Agropyron
0 £ 5 - I K p 7 - 7 ^ .07 |/ / / / / | 55.6
Juniperus-Oryzopsis % « iS
0 10 V X. X X
Pinus-Juniperus
ZZZZ^ A •H o I I I a I -5 3 -
vegetation are discussed in their order of importance relative to
community-type distinction.
Shrub vegetation. As a group the shrubs represent the most impor
tant life-form element in the vegetation of the badlands. In five of
the badland community-types, shrub vegetation comprises no less than 68
percent of the total cover, and in most cases well over 80 percent.
Their dominate character in the community structure is quite apparent
from field observations, and the quantitative abundance and frequency
information bears this out. The typical physiognomic appearance of the
badland vegetation is characteristically one of shrubs.
The community-type in which shrub vegetation composes the greatest
percentage of the vegetative cover is the Atriplex-Artemisia community,
w ith 98.6 percent (Appendix: IV). The principal dominant species include
Atriplex confertifolia and Artemisia tridentata. Other important shrub
constituents include Eriogonum multiceps, Chrysothamnus graveloens, and
Gutierrezia sarothrae. The vegetative cover of the Sarcobatus community
is composed of 96.5 percent shrubs, and includes Sarcobatus vermiculatus
as the dominant. Other abundant shrubs include Artemisia tridentata,
Atriplex confertifolia, and Suaeda fruitocosa (Appendix III).
The remaining community-types are composed of a lower percentage of
shrub abundance, with an increased incidence in grass abundance. The
total vegetative cover of the Artemisia-Atriplex-Agropyron community is
composed of 89.7 percent shrubs, and the dominant species are Artemisia
tridentata and Atriplex confertifolia. The Artemisia-Agropyron commun
ity is composed of 71.5 percent shrubs, and the dominant species is
Artemisia tridentata. The Rhus-Agropyron community is composed of 68.2 -.Jit- percent shrubs, and the dominant species is Rhus trilobata.
The remaining two badland communities are principally dominated by
trees, and shrubs are probably not important in them, except as the
differences in species in each represent changes in environmental condi
tions, Shrubs make up only 3*8 percent of the total vegetative cover in
the Juniperus-Agropyr on community, prim arily composed of Ribes cereum,
Rhus trilobata, and Artemisia tridentata. The Pinus-Juniperus community is composed of 3.5 percent shrubs, mainly composed of Rhus trilobata,
Artemisia cana, and Gutierrezia sarothrae. Less than one percent of the vegetative cover of the J uniperus-Oryz opsis community is composed of
shrubs. Only three species were encountered, namely Rhus trilobata,
Gutierrezia sarothrae, and Symphoricarpos occidentalis.
Of the five shrub dominated community-types, four groups are obvious. The first of these is the Sarcobatus community supporting 9.9 feet per hundred feet of line of Sarcobatus vermiculatus. No other c ommuni ty-type has near this abundance of Sarcobatus vermiculatus
(Figure lli). The second is the A tripl ex-Artemi si a community, dominated by Atriplex confertifolia. No other community-type supports this species to such proportions. The third is the Rhus-Agropyron community, dominated by Rhus trilobata. This is the only c ommuni ty-type in which
Rhus trilobata occurs in such quantities.
The fourth group of the shrub dominated community-types includes the Artemisia-Atriplex-Agropyron and the Artemisia-Agropyron communities, dominated by Artemisia tridentata. The distinction between these two is obviously in terms of Atriplex confertifolia abundance. In the Artemisia-
Atriplex-Agropyron community, Atriplex confertifolia is more than half as abundant as Artemisia tridentata, and forms a very conspicuous part of the vegetation. In the Artemisia-Agropyron community, however, there is almost a complete lack of Atriplex confertifolia. The latter species does occasionally occur locally in some locations, but its role in the
structure of the community is obviously minor, having only 12.8 p e rc e n t
of the abundance of Agropyron spicatum, and 2.2 percent of Artemisia tridentata (Figure li;, and Appendix V and VI),
The distinction between tree-dominated community-types is more
subtle on the basis of shrub vegetation. In both the J unip erus-Agropyr on and the Pinus-Juniperus communities, Rhus trilobata is the most abundant
shrub. However, in the former c ommuni ty-type Artemisia tridentata is conspicuous, but in the latter it is completely lacking. Conversely, in the Pinus-Juniperus community, Artemisia cana is abundant but is lacking in the Junip era s-Agr opyr on community. The Junip eru s-Oryz ops is community has a conspicuous lack of shrub species, none of which are significantly abundant to impart any indication that they play an important role in community structure.
Two shrub species, Artemisia tridentata and Atriplex confertifolia, represent the two most abundant shrubs and the most wide-spread dominants in the badlands. Together these two species are dominants on nearly ^0 percent of the land area of the badland topography in southeastern Mon tana. Artemisia tridentata is a common constituent of the surrounding grasslands, and is wide spread throughout southeastern Montana, Beetle
( i 960 ) feels that the particular species in this area is Artemisia tri dentata subsp. vaseyana, which reaches its greatest development to the south in Wyoming. The general abundance of this plant in southeastern -5 6 -
Montana is of such a magnitude that its presence on the badland slopes seems almost expected. Even if badland topography did not exist in this area, it is certain that Artemisia tridentata abundance would be but little affected.
This is probably not quite true for Atriplex confertifolia, which
seems to reach its greatest abundance in the Great Basin (Billings 19it9),
This species is not found in the grassland vegetation of the study area, but is restricted entirely to the badland topography.
Although both Atriplex confertifolia and Sarcobatus vermiculatus
are more commonly thought of as northern desert species, Sarcobatus vermiculatus is a rather common species in many of the valleys and bottomlands of southeastern Montana, Extensive stands of this latter
species are common in the bottomlands as far west as Whitehall, Hardin,
and Billings, as well as on some of the flats and river terraces in the
study area.
Tree vegetation. Two of the badland c ommuni ty-types, the Juniperus-
Agropyr on and the Pinus-Juniperus communities, are dominated by tree vegetation. Included in this group, although not a badland community is the Juniperus-Oryzopsis community, A fourth community, the Rhus-
Agropyron community, was occasionally found to have a few scattered pine
and ju n ip e r p la n ts , b u t th ey a re n o t c o n s is te n t members of i t s v eg eta
tion, In the latter case, trees compose only 18,7 percent of the total veg etative c over,
Only two species of trees were encountered in the sanpling of the badland vegetation, Juniperus scopulorum and Pinus ponderosa, although a few scattered plants of Juniperus horizontalis were observed. In the ••5 7 —
Juniperus-Agropyron commanity tree cover accounts for 93,5 percent of the total vegetative cover. Very few trees of pine were encountered in this community, the principal species being Juniperus scopulorum. In the
Pinus-Juniperus community, tree cover composes88.1 percent of the total vegetative cover. Pinus ponderosa comprises about 70 percent of the total cover, and Juniperus scopulorum about 18 percent. The Juniperus-
Oryzopsis community is composed of 96.9 percent trees of the total vege tation, Juniperus scopulorum comprising96 percent, and Pinus ponderosa
less than one percent.
Community differentiation based on tree abundance is easily accom plished for the two tree-dominated badland c ommuni ty-types. The great abundance of Pinus ponderosa in the Pinus-Juniperus community, and its scarce presence in the Juniperu s -Agr opyr on community serve to distin guish these two communities. Distinction between the latter community and its close relative, the Juniperus-Oryzopsis community, based on tree species presence alone is more difficult. In terms of relative abundance the J uniperu s -Or y z op s i s community has a much higher cover of
Juniperus scopulorum, and a much higher frequency (Appendice VIII and IX).
Pinus ponderosa is a common southeastern Montana species, princi pally on north slopes and other moist areas. Booth (1950) indicates that the common eastern Montana species may be Pinus ponderosa var. scopulorum, a variety of the typical Rocky Mountain form. Occasionally morphological variations observed in some of these plants indicate that there may be more than one ecotype present in the study area. Most usually Pinus ponderosa attains a maximum height of 1|0 to 60 feet in the badlands, with diameters seldom exceeding 12 inches at breast height. -5 8 -
Grass and grasslike vegetation. Grasses and grasslike plants com pose a greater part of the vegetation of the c ommuni ty-types than forbs, and perhaps are ecologically one of the most important groups of plants in this case. A summary of the important grasses occurring in each commun!ty-type is presented in Figure Only four of the most abun dant species of grasses were included in the histogram, in addition to one subdominant of the Juniperus-Oryzopsis community.
Grasses are most abundant in the Artemisia-Agr opyr on community, composing 28.2 percent of the total abundance. The most abundant species, and by far the most important ecologically, is Agropyron spicatum with an abundance of 2.2 feet per hundred feet of line. Other important grasses include Bouteloua curtipendula and B. gracilis. The
Rhus-Agropyron community is composed of 12.2 percent grasses, primarily of Agropyron spicatum and Bouteloua curtipendula. The Artemisia-
Atriplex-Agropyron community is composed prim arily of Agropyron spicatum and Oryzopsis hymenoides. Grass cover comprises 10.2 percent of the total cover in this community. The Pinus-Juniperus community is unique in that although grasses comprise only 7.5 percent of the total cover, a greater number of highly abundant species is present than in any of the other community-types. The most abundant species include Agropyron spicatum, Andropogon scoparius, Bouteloua curtipendula, B, gracilis, and
Carex filifo lia.
Of the remaining badland commun!ty-types, the Sarcobatus community is composed of 3.2 percent grasses. The most important species include
Bouteloua gracilis and D istichlis stricta. The Junip erus-A gr opyr on community is composed of 2.3 percent grasses, primarily Agropyron -5 9 - spicatum and Bouteloua curtipendula. The lowest grass composition of a ll the c ommuni ty-types occurs in the Atriplex-Artemisia community, with a composition of 1*2 percent. Only two species of grass were encountered in this community, Agropyron spicatum and Oryzopsis hymenoides.
The Juniperus-Oryzopsis community represents a rather special case, in that one species of grass, Oryzopsis micrantha, and Carex pensylvanica were found in none of the other community-types. The name of this com munity was intended to reflect this phenomena rather than the relative
abundance of Oryzopsis micrantha. Agropyron spicatum is the most abun
dant grass, but the relatively high abundance of Oryzopsis micrantha is more striking and conspicuous. The total grass composition is 1,9 per cent of the total abundance.
From the standpoint of distinguishing between community-types on the basis of grasses, the abundance of the most important species is quite striking. The Sarcobatus community can be distinguished on the basis of the high abundance of Distichlis stricta, Bouteloua gracilis,
Agropyron sm ithii, and the exclusive occurrence of Agropyron dasystachyum. The Atriplex-Artemisia community is recognizable on the basis of the almost total lack of grass cover, and the occurrence of
only two or three species ^ere they are present.
The Artemisia-Atriplex-Agropyron, Artemisia-Agropyron, and Rhus-
Agropyron communities have an interesting feature in common, that of supporting by far the greatest abundance of Agropyron spicatum. In each community-type mentioned above, this one species composes more than
68 percent of the abundance of all grasses. The abundance values for
Agropyron spicatum are 1,1:, 2,2, and 1,3 feet per hundred feet of line -6 o - respectively in each community-type. On basis of the abundance of the subordinate grasses, including Bouteloua curtipendula, B. gracilis,
Stipa comata, and S. viriduala, the Artemisia-Agropyron community is easily distinguished. Also, the latter community supports almost twice as much Agropyron spicatum as the other community-types, The other two communities do not support Stipa viridula. A comparison of the grass species in the Rhus -Agropyron and the Artemi sia-A trlp 1 ex-Agr opyr on com munities shows that almost the same identical species are present.
There are two rather significant differences in the grass composition of these two community-types however. The Rhus -Agr opyr on community sup ports a substantial cover of Andropogon scoparius, which is completely lacking in the Artemi s i a-Atrip lex-A gr opyr on community, and a compara tively much greater abundance of Bouteloua curtipendula than the latter community.
Of the remaining community-types, the Juniperus-Oryzopsis community can easily be distinguished on the basis of the conspicuous and exclu sive presence of Oryzopsis micrantha. The most abundant grass in the
J uniperus-Agropyron community is by far Agropyron spicatum, and the other species are comparatively far less important. In the Pinus-
Juniperus community the high abundance of several species of grass is striking. Although Agropyron spicatum is the most abundant species,
Andropogon scoparius and Bouteloua curtipendula taken together have a higher abundance. Relative to the grass vegetation, dominance is shared in this community by several species rather than one.
The general over all abundance of Agropyron spicatum is of signifi cant importance in the badlands. This species is the most abundant - 61 -
grass species in every community-type except the Sarcobatus community.
The ecological amplitude of this species is considerably wider than that
of any other species of grass in the badlands. Field observations and
analysis of the vegetation data indicate that, in terms of abundance and
frequency, Agropyron spicatum is ecologically the most important species
of grass in the badlands of southeastern Montana,
Forb vegetation. Abundance data for forbs are not included in
Figure iL because no species of forb attained a sufficient abundance
magnitude comparable with that of the dominant and subdominant species,
Forbs compose less than one percent of the total abundance for every
stand of each community-type studied. The greatest forb composition
occurs in the Rhus-Agropyron and Juniperus-Oryz ops is communities, making up 0*9 percent of the total abundance in each. The most abundant forbs
in the Rhu s -Agr opyr on community include Artemisia dracunculus, Crypt-
anthe bradburiana, and Sphaeralcea coccinea. In the Juniperus-Oryzopsis community the most important forb species include Achillea millefolium,
Cerastium arvense, and Salidago missourlensis, In the Juniperus-
Agropyr on community, Cerastium arvense has the greatest abundance of any forb species in all the plant community-types.
In the Sarcobatus community the total forb abundance is 0,3 percent of the total species abundance, and the important species include Opuntia polycantha and 0. fragilis. The number of forb species in the Atriplex-
Artemisia and the Artemisia-Atriplex-Agropyron communities are very few.
These two communities have the lowest forb abundance of all the eight communities studied, being 0,2 percent of the total abundance. The most abundant species in the former community is Phlox caespitosa, and —62—
Sphaeralcea coccinea in the latter, Sphaeralcea coccinea is also the most abundant forb in the Ar temi s ia -A gr opyr on community, with a forb composition of 0,3 percent. Phlox caespitosa is the most abundant forb in the Pinus-Juniperus community,
Forbs are not a part of the dominant vegetative structure in any of the community-types and their ecological role is probably quite signifi cant, In this particular study the sanpling technique was designed with the dominant species primarily in mind. However, quantitative data for secondary forb species were collected for what information it might add to the total study,
Badland Microcommunities
Several interesting microcommunities were observed in the badlands occurring with the major community-types. The microcommunities are usually quite small, ranging from several square feet to several hundred square feet, and collectively composing less than one percent of the total badland surface area. Quantitative vegetation data were not col lected for these microcommunities, but species lists and field notes on estimated abundance were made. In some cases soil samples were also c o lle c te d .
Microcommunities are dominated by one species in most cases, and are named for the dominant in each case. The various microcommunities studied are: the Eriogonum multiceps, Sporobolus cryptandrus, Distichlis stricta, Agropyron sm ithii, Penstemon eriantherus, and the Oxytropis lam bertii microcommuni tie s , ■^3"*
Dominant Species Distribution
A considerable amount of species overlapping occurs among the
various community-types. This is to be expected because the ecological
tolerance lim its of most species are usually broad enough to permit a
certain amount of habitat overlap. A dominant species in one community-
type can be expected to be a subdominant in another kind, and possibly a
secondary species, or completely lacking in another community-type. The
variation in the environmental factors among habitats thus influences
the ecological status of every species. One measure of habitat influ
ence is the determination of the relative variation of a species socio
logical behavior relative to different habitat conditions.
Dominant species variation among community-types. Of all the plant
species encountered in the vegetation sampling, only seven are of domi
nant or sub dominant status. These seven species are: Agropyron
spicatum, Artemisia tridentata, Atriplex confertifolia, Juniperus scopu
lorum, Pinus ponderosa, Rhus trilobata, and Sarcobatus vermiculatus.
Each of these species is a dominant in at least one community-type
except for Agropyron spicatum. Also, each of the seven species occur in
different community-types other than that in which they are the dominant,
in which case they occur as subdominant or secondary species. For
example, Artemisia tridentata is a dominant in the Artemis ia -Atrip lex-
Agropyron and the Artemisia-Agropyron communities, a subdominant in the
Atriplex-Artemisia, and a secondary species in the Sarcobatus and
Juniperu s-Agropyron community-types,
A chi-square analysis was made to test if the abundance of each of these species is significantly different among the various community- -6U- types in which they are found. The abundance of each species in one
stand of a community-type was compared with its abundance in a paired
stand of another community-type. Stands of different community-types were paired only if they occurred at the same location. For example,
stands of the Artemisia-Atriplex-Agropyron and the Artemisia-Agropyron
communities were sampled at three of the same locations (Appendix II),
and were thus three paired stands. In one case, stands of two community-
types could be paired at only one location, whereas in most instances pairing was possible at three or four locations.
Stands of different community-types were paired only if they sup ported the same species as a dominant or subdominant. For instance,
stan d s of th e Juniperus-A gropyron and th e A trip le x -A rtem isia communi ties were never paired because the major species are different in each.
The null hypothesis was made that there is no significant differ
ence in the abundance of a species that occurs in different community- types, The observed abundance values in each of the paired stands were averaged at each location for the particular species being considered.
This average a t each location was considered the expected abundance as
suggested by Snedecor (19^6) and Ellison (19^9)* These observed and expected values were used in calculating the chi-square for each of the m ajor sp e c ie s between each communi ty -ty p e in which i t occurred.
Table 2 shows the results of this chi-square analysis, in which is also indicated the community-types which were paired for each species.
Appendix II indicates the number of locations at which stands of the community-types were paired. The results of this analysis indicate that there is a highly significant difference in the abundance of the T able 2 , Summary of chi-square analysis of dominant species abundance variation between community' ty p e s.
Species Community-Types Compared C hi-square
Agropyron Artemisia-Atriplex-Agropyron + Artemisia-Agropyron 320.2 ** spicatum Artemisia-Atriplex-Agropyron + Atriplex-Artemisia- 317c8 ** Artemisia-Agropyron + Rhus-Agropyron 71.6 ** Artemisia-Atriplex-Agropyron + Rhus-Agropyron A rtem isia Artemisia-Atriplex-Agropyron + Atriplex-Artemisia 910.6 ** tr id e n ta ta Artemisia-Atriplex-Agropyron + Sarcobatus 350.2 ** Artemisia-Atriplex-Agropyron + Artemisia-Agropyron 580.6 ^ Atriplex-Artemisia Sarcobatus 20.6 **
A trip le x Artemisia-Atriplex-Agropyron + Atriplex-Artemisia 266.8 ** confertifolia Artemisia-Atriplex-Agropyron + Artemisia-Agropyron 2129.2 ^ I Atriplex-Artemisia + Sarcobatus 941.2 ** ON vn I Ju n ip eru s Juniperus-Agropyron + Pinus-Juniperus 4464.2 ** scopulorum Rhus Rhus-Agropyron + Pinus-Juniperus 1659.2 ** t r i l o b a t a
Pinus Pinus-Juniperus + Juniperus-Agropyron 7501.8 ** ponderosa
S arcobatus Sarcobatus + Atriplex-Artemisia 1812.0 ** vermiculatus
* probability level between .05 and .01 ** probability level less than .01 major species between community types#
Although Agropyron spicatum is not a dominant species in any
community-type, it was included in this analysis because of its almost ubiquitous occurrence as a subdominant# This species is a subdominant in the Artemisia-Atriplex-Agropyron, Artemisia-Agropyron, Rhus-Agropyron,
and th e ^uniperus-Agropyron communities. It is only a secondary species
in all of the remaining community-types,
Dominant species variation within community-types. Another measure
of environmental variation on the distribution of vegetation is the sig nificance of the differences between dominant and subdominant species within the same community-type# Such an analysis was designed to mea
sure the uniformity in botanical composition from stand to stand within
each community-typeo The implication from such an analysis would be
that habitats repeat themselves with a degree of regularity as indicated by the mathematical measurement of variation. If the apparent differ
ences are consistent and significant the indication would be that they are not chance differences, but are due to rather specific and consistent
environmental c onditi ons,
A chi-square analysis was made to test for the significance of the differences between major species occurring in each community-type according to the method of Cook and Hurst (1962). Table 3 is a summary of this analysis. The results of this analysis indicate that there is more th a n 99 chances in a hundred that the disparity between species is due to environment, and less than one chance in a hundred that it is due to sampling# Cole (19h9) used a similar chi-square technique employing frequency -6 7 -
Table 3 , Summary of the chi-square analysis of the variation in the abundance between major species within community-types.
C ommuni ty-T ype Species Compared Chi-square
Sarcobatus vermiculatus + Artemisia tridentata 1 2 6 6 .S S arco b atu s Sarcobatus vermiculatus + Atriplex confertifolia L86.3 ^ Sarcobatus vermiculatus + Sueada fruiticosa 935,6 **
Atriplex confertifolia + Artemisia tridentata 6U1.6 -îHf A trip le x - Atriplex confertifolia * A rtem isia Eriogonum multiceps 559.5 ^ Atriplex confertifolia + Agropyron spicatum 79.9 **
Artemisia tridentata + A rte m isia - Atriplex confertifolia ii90.3 ^ A trip le x - Artemisia tridentata + Agropyron Agropyron spicatum 508.9 Atriplex confertifolia + Agropyron spicatum 367.8
A rte m isia - Artemisia tridentata + Agropyron Agropyron spicatum 270.U **
Rhus-Agropyron Rhus trilobata + Agropyron spicatum 3i.08 .1 **
Ju n ip e ru s- Juniperus scopulorum + Agropyron Agropyron spicatum 558.2 **
Ju n ip e ru s- Juniperus scopulorum + Oryzopsis micrantha 93.7 ^
P in u s- Pinus ponderosa + Juniperus scopulorum 9581.9 iwe Ju n ip eru s
^ probability level between ,05 and .01 ** probability level less than .01 -6 8 - data to quantify the amount of interspecific association between organ isms, Positive association is to be anticipated in the case of two species with overlapping habitat requirements which interact in such a way as to favor mutual presence. Although interspecific association was not investigated in this study, there are indications which suggest a certain amount of positive association between Artemisia tridentata and Agropyron spicatum in most of the badland habitats,
Edaphic Influences and Community Distribution
Soil samples were collected from various widely scattered stands of each community-type studied. The soils of some of the stands which were sampled for botanical composition were not collected, particularly those stands studied during the early phases of the study. However, a total of 103 soil samples were collected, counting both upper and lower hori zons, ninety-three of which were collected in badland community-types, eight from the Juniperus-Oryzopsis community-type, and two from the bad land microcommunities.
The presence of normally developed soils is largely lacking in the badland community-types. The limited amount of developed soils found belong to the azonal order of soils, and consist of the Lithosol and
Regosol great soil groups, Lithosols are the most extensive of the two, and are commonly found where massive sandstone occurs near the surface on gentle slopes or on flat mesa tops and local peninsular-like benches which project out from the badland slopes. These areas uaially support stands of the Pinus-Juniperus community-type, Regosols are commonly found as knolls of colluvium or sandstone outcrop remnants at the base - 6 9 -
of badland slopes, Plnus-Juniperus stands are usually found on these knolls also. The soils of the Juniperus-Oryzopsis community-type are
also probably Regosols,
For the most part the material in the badlands which serves as a medium for plant growth is not developed soil in the sense of the pedol
ogist, By far, the greatest amount of soil material is composed of con
solidated and unconsolidated geological materials composed of interbedded
shales of clay and s ilt, deposits of porcellanite, and colluvial talus
slopes, Colluvial slopes are composed of unconsolidated fragments of sandstone, silts tone, clay and s ilt shales, and often porcellanite frag ments which have accumulated from weathered material on the slopes above.
Often there was some difficulty in clearly designating the soil horizon sequence in this material. Although loosely referred to as soil, this material does not display the typical horizonation of normal soils. Therefore, where some differentiation in the soil material was apparent the different layers were referred to as upper and lower hori zons, When soil samples were collected from the very steep surfaces of interbedded shales of clay and silt, the clay material was referred to as the upper horizon, and the silt as the lower. This also is a non conformity in the sense that both beds are horizontal sedimentary deposits which are exposed on the slope surfaces, and have the appear ance of parallel bands. In porcellanite beds horizonation was observed at only one location, and the soil analysis data from it are not gener ally applicable to all lower horizons that may occur in this material.
A general summary of the soil analyses made for both horizons of each community-type is presented in Table ü. Each value presented Table 4. Summary of the soil characteristics of the upper and lower horizons for each community-type. (Values represent averages of soil samples.)
Community- Number P ercen t P ercent P ercent P ercent Perman, S o il Cond. Sodium Calcium Type S o il Sand S i l t Clay Coarse W ilt ing pH mmhos. me c/lOO me./1 0 0 Samples Frgrats-. P ercent 25°C. grams grams Sarcobatus Upper Ik 19.9 4 l . l 39.0 11 13.3 7 .9 7 .2 9 .1 9 .1 Lower 8 11.0 45.4 43.6 _ 8 15.4 8 .0 8 .7 12.0 15.4 A^triplex- A rtem isia Upper 9 14.4 39.2 46.3 28 10.5 7 .6 6 .2 2 .9 11.4 Lower 9 20.5 43.5 35.9 4 l 9.5 7 .7 5.8 4 .1 10.7 Artemisia- A trip le x - Agropyron Upper 8 31.4 35.1 34.0 18 9.5 7 .6 1.5 1 .0 10.5 Lower 3 19.6 58.0 22.2 13 9.4 8 .3 4 .9 5.5 14.7 I A rtem isla- I Agropyron Upper 5 32.6 30.3 37.1 21 10.9 7 .8 0 .7 0 .4 1 1 .7 Lower 5 37.0 2 7 .7 35.2 17 9 .3 7 .9 1.8 0*9 11 .9 Ettius- Agropyron Upper 10 51.9 2 9 .9 17.2 47 8 .9 7 .7 0 .5 0 .3 14.2 Lower 1 40.4 54.2 5.5 70 19.1 7 .9 2 .5 0 .4 400.0 Juniperus- Agropyron Upper T 2 5 .1 32.3 42.5 21 12.1 7 .7 0 .7 0 .4 8 .0 Lower 5 28.4 35.3 36.4 12 10.6 7 .9 0 .7 0 .5 9.5 Juniperus- O ryzopsis Upper k 32.1 38.5 29.4 5 10.4 7 .6 0 .6 0 .3 7 .3 Lower k 26.1 41.8 32.0 8 10.3 7.8 0 .9 0 .3 8 .8 Pinus- Ju n ip eru s Upper 6 34.4 31.4 34.2 10 9.2 7 .7 0 .6 0 .4 9.3 Lower ... 42.3 42.4 12 9 .9 7.8 0.6 0 .5 10.7 -7 1 - usually represents an average of from several to lli samples.
Soil Physical Properties
Soil texture. A soil textural analysis of the various soil frac tions ( sand, silt, and clay) was made to determine if there was a tex t u r a l d iffe re n c e among th e v a rio u s com m unity-types s tu d ie d , A summary of the percent sand, silt, and clay for the upper and lower horizon of each community-type is presented in Table h»
On the basis of percent sand in the upper horizon, three groups of community-types can be separated (Table I 4), The first of these include the Sarcobatus and the Atriplex-Artemisia community-types with a rela tively low percent sand. The second group includes the Artemisia-
A trip lex-Agr opyr on, Artemisia-Agropyron, Juniperus-Agr opyr on, Juniperus-
Oryzopsis, and the Pinus-Juniperus community-types with a moderate percentage of sand. The last community-type, the Rhus-Agropyron commun ity, has a much higher percent sand than any of the other community- ty p e s.
The Atriplex-Artemisia community-type has the least amount of sand, and the greatest amount of clay in the upper (clay) horizon, and repre sents the heaviest soil of all of the community-types. This community can be separated from the Sarcobatus community primarily on the basis of the coarser fractions in each of the soils. The former community has a substantially lower percentage of sand and s ilt than the Sarcobatus community. These relationships change somewhat in the lower horizons of the soils of these two communities. The A triple x-Artemi si a community has a lower percent of clay than the Sarcobatus community, and a higher .7 2 - percent of sand.
Of the second group of community-.types with moderate percentages of sand in the upper horizon, the J unip erus -Agr opyr on community can be dis
tinguished from the others on the basis of clay content. This community-
type has the highest clay content of this group, and the lowest sand
content. The Juniperus-Orzopsis community can be distinguished as
having the highest percentage of silt and the least amount of clay. The
Pinus-Juniperus community has the highest percentage of sand of this
group of community-types. Distinction of the remaining two shrub-
dominated communities on the basis of texture has proven quite diffi
cult, However, on the basis of texture in the lower horizon, the
Artemisia-Atriplex-Agropyron community has the greatest amount of s ilt,
and the least amount of clay. On the other hand, the Artemisia-
Agropyron community has the least amount of s ilt in the lower horizon,
and the greatest percentage of sand.
The Rhus -Agr opyr on community is distinct from a ll the other
community-types in terms of its high sand content. In both horizons, this community has by far the greatest sand content with $ 1.9 p ercen t in the upper, and i;0.h- percent in the lower horizon. Also, it has the
lowest clay percentage in each horizon, with 17.2 and $.$ percent in the upper and lower horizons respectively.
There appears to be no difficulty in distinguishing between the
Rhus-Agr opyr on and the Atriplex-Artemisia communities on the basis of texture. As might be expected, it seems that the more closely related community-types are the most difficult to distinguish between on the basis of soil texture. Thus the Sarcobatus and the Atriplex-Artemisia «73- communities are more similar to each other than to any other community» typBo The sim ilarity between the Artemisia-A trip lex~Agr opyr on and the
Artemisia-Agropyron communities is striking^ the primary differences being in the s ilt and clay composition^ The latter community-type has a greater percent sand and clay content than the former community^
Little difficulty arises in the separation of the three tree- dominated community-types„ The Juniperus-Agropyron community has the least amount of sand and the greatest amount of clay in the upper hori»
zon of this group, The Pinus-Juniperus community has the greatest
amount of sand^ and the least amount of silt In the upper horizon*
Percent coarse fragments* A distinction among the community- types based on the estimated percent coarse fragments is not possible in
all cases* A summary of the percent coarse fragments by volume for the upper and lower horizons of each community-type is presented in Table ko
The Rhus-Agropyron community-type has by far the greatest percentage of coarse fragments in both the upper and lower horizons^ being kl and 70 percent respectively, of any other c ommuni ty-type* The Juniperus-
Oryzopsis community has the lowest percent coarse fragments in both hor izons, being ^ and 8 percent respectively*
The percent coarse fragments in both horizons of the Atriplex-
Artemisia community do not necessarily represent the composition of rock material* The greatest proportion of the coarse fragments reported in this community represent consolidated clay and silt aggregates, and are considered more or less impenetrable by plant roots*
Three community-types, the Sarcobatus, Junip eru s -Or yz opsis „ and the
Pinus-Juniperus communities, have very low percentages of coarse «=7U“ fragments o The Juniperns-Oryzopsis community has the lowest percentage of all community-types in the upper horizon. The other two have similar percentages in the upper horizon^ but in the Sarcobatus commiunity the percent decreases with depth. The Juniperu s-Oryz op si s community also has 8 percent coarse fragments in the lower horizon, but the percentage decreases in the upper horizon. In the Pinus-Juniperus community on the other hand, the coarse fragment content is higher than in the Juniperus-
Oryzopsis communitybut also increases with depth (Table h) o
Three community-types, the Artemi sia -Atrip lex-Agr opyr on, Artemisia-
Agropyron, and the Juniperus-Agropyron communities, have sim ilar coarse fragment contents in the upper horizons. The percent coarse fragments in the Artemis ia-A gr opyr on and the Juniperu s -Agr opyr on communities are both 21 percent in the upper horizon. However, a distinction exists in the lower horizon, where the former community-type has 17 percent and the latter 12 percent coarse fragments (Table i|). The Artemisia-
Atriplex-Agropyron community has 13 percent in the lower horizon.
The differences reported in percent coarse fragments of the soils of some of the community-types are very small, and are within the lim its of sampling and analysis error. These data suggest that small differences among coirmiunity-types are not significant in most cases.
The Rhu s -Agr opyr on and Juniperus-Qryz opsis communities are the only ones that are clearly distinguishing from all the other community-types,
Permanent wilting percentage. The permanent wilting percentage of the soil is generally agreed to represent Lh^ moisture content at which plants w ill permanently w ilt and die (Richards and Weaver 19^3)« A soil matrix tension of 15 atmospheres is considered the stress limit for - 7 ^ -
available mois tare, and as reported here is entirely a function of the
proportion of the soil fractions present. Generally, as the percent
clay increases in a soil, the permanent wilting percentage increases,
and conversely, as the percent sand increases, the permanent wilting
percentage decreases. A summary of the permanent wilting percentages
of the upper horizon for each plant community-type is presented in
Table Uo
For the most part these data indicate that the differences among
the community-types in terms of permanent wilting percentage are within
the lim its of sampling and analysis error (Table U).
There appears to be an obvious distinction between the Sarcobatus
and Juniperus -Agr opyr on communities, and the rest of the community-types,
Both of these communities also have a high percentage of clay and silt.
Although the Atriplex-Artemisia community has the highest clay content,
the permanent wilting percentage in the upper horizon of this community
is relatively low.
Both horizons of the Sarcobatus community-type have higher perma nent wilting percentage values than any of the other community-types, w ith 1303 and percent respectively in the upper and lower horizons.
The next highest values are those of the Junip eru s -A gr opyr on community w ith 12o2 and 10*6 percent respectively in the upper and lower horizons.
The upper horizon data of the Rhus-Agropyron community shows this community-type to have the lowest permanent wilting percentage, which is an expression of the high sand content. For the remaining community- types, and except for the Atriplex-Artemisia community, the Artemisia-
Agropyron community has the highest wilting percentage and percent clay -7 6 - content in the upper horizon. The Atriplex-Artemisia and the Juniperus^
Oryzopsis communities are very similar in permanent wilting percentage in the upper horizon^ although the former community has a greater per- centage of clay. The Artemisia -Atri p lex-Agr opyr on and the Pinus-
Juniperus communities are quite similar also^ being 9.^ and 9.2 p ercent in the upper horizon respectively. Both communities also have similar percent clay contents in the upper horizon.
Differentiation among community-types on the basis of permanent wilting percentage of the lower horizon is as subtle as it is for the upper horizon. There appears to be no major differences among the values for the lower horizon of the Atriplex-Artemisia, Artemisla-
Atriplex-Agropyron, and the Pinus-Juniperus communities.
On the basis of the data analyzed, it is concluded that the perma nent wilting percentage is not a consistent or reliable factor upon which to base community distinction. However, the Sarcobatus and the
Junip eru s -A gr opyr on communities are easily distinguished fTora the other community-types. These two community-types can be distinguished from each other in the sense that the Sarcobatus community has a much higher combined s ilt and clay content, with a consequent higher permanent wilting percentage.
Soil Chemical Properties
Soil reaction. Soil reaction, or pHg is a measure of the soil acidity or alkalinity based on the hydrogen ion concentration in the soil solution. The principal value of soil pH analysis is that it indicates indirectly the relative amounts of certain exchangeable -7 7 -
cations, particularly in this case sodium and calcium. Soils with pH
values in excess of 8.5 are generally high in exchangeable sodium, and
may have a high concentration of calcium, while pH values below 7.0
indicate a high hydrogen ion concentration. High pH values of arid-land
soils usually indicate high salt contents,
A summary of the soil pH for the upper horizon of each plant
community-type is presented in Table U.
The results of this analysis indicate that there are no major
differences in soil pH among the community-types studied. Although the
pH differences are relatively subtle among the community-types, the
Sarcobatus community appears to consistently have the highest soil reac
tion, Soil reaction values of as high as 8,8 in the lower horizon have
been recorded for this community-type in the vicinity of natural seeps.
Soil conductivity. Conductivity is an electrical measure of the
amount of soluble salts present in the soil solution. The unit of
expression is the millimho, and is equal to 1000 times the reciprocal of
one ohm, A summary of the conductivity of the upper horizon for each
plant community-type is presented in Table ii.
On the basis of conductivity there are two groups of community-
types easily separable. The first group includes the Sarcobatus,
A triplex-A rtem isia, and the Ar temi s i a -A tr ip lex-Agr op yr on communities.
The second group includes a ll of the remaining community-types.
The Sarcobatus community has the highest conductivity values in
both horizons of all the community-types. The Atriplex-Artemisia com
munity has the second highest conductivity, and differs from the
Sarcobatus community somewhat. There is a distinct difference in the -7 8 . conductivity of the Artemisia-A trip lex^Agrop.yron community Arom a ll the other community-typeso It has a much lower salt content in the upper horizon from the preceding two community-types ^ and a much higher salt concentration in the lower horizon than all the remaining community- ty p es «
The Artemisia-Agropyron community^ although with a relatively low salt content in the upper horizon, can be distinguished in terms of the lower horizonc The remaining four community-types cannot be readily distinguished on the basis of soil conductivity because in all cases, both horizons show very similar salt concentrations,
Ex tractable sodium and calciumo As the concentration of sodium increases there is a concomitant increase in soil pHo From the stand point of plant nutrition very high concentrations of sodium induce deficiencies of the cations more critical to plant growths It has generally been found that a very high sodium concentration in the soil is an indication of a high sodium content in the plants growing in it
(Rickard 196^, Fireman and Hayward 1952)o Due to leaching, sodium con centrations are usually higher in lower horizonso
It appears that high sodium concentrations mainly induces defi ciencies of calcium in soils « Calcium is more critical to the plant from the standpoint of nutrition than sodium» With increasing concen trations of calcium, the soil pH usually also increases to a point »
It was found that sodium concentrations increase with increased soil depth in most cases » The greatest variations in individual samples occur within the Sarcobatus, A triplex-Artemisi a, and the Artemi si a-
A trip lex-Agr opyr on communities» However, sodium concentrations on the “ 7 9 ”
whole were relatively uniform for each horizon in each c ommuni ty-type»
On the basis of the mi H i equivalents of extra c tab le sodium in the
upper horizon, three community-types can be distinguished (Table 1^)»
The Sarcobatus community has the greatest sodium content of a ll the
community-types o The Atriplex-Artemisia community has a much lower
sodium concentration than the Sarcobatus community, but much greater
than a ll the other community-types» The Artemisia-A trip lex-Agropyr on
community can be differentiated by the relatively low sodium content in
the upper horizon, and with a much higher concentration in the lower
h o riz o n .
The Artemisia-Agropyron community has a relatively similar sodium
concentration in the upper horizon as the remaining community-types,
but a relatively higher concentration in the lower horizon. The differ
ences in th e m illie q u iv a le n ts of sodium fo r th e rem aining fo u r community»
types are very small, and on this basis the community-types cannot
effectively be separated.
There are two principal groups of community-types in terms of the
milliequivalents of calcium. The Atriplex-Artemisia, Artemisia-A triplex»
Agropyron, Artemisia-Agropyron, and Rhus Agropyron communities have much higher calcium contents than the other four community-types. The Rhus-
Agropyron community-type has the highest concentration and is followed by the Atriplex-Artemisia community. Actually, reliable separation of the Atriplex-Artemisia, Artemisia-A triplex-Agropyron, and the Artemisia-
Agropyron communities probably cannot be made on the basis of calcium a lo n e .
The second group of community-types include the Sarcobatus, “80“
Juniperus-Agropyron, Juniperas-Qryzopsis, and the Pinus-Juniperus com munities^ all with lower calcium concentrations than the above four community-types o The moister north slope site of the Juniperus -
Oryzopsis community has the lowest calcium content of all the community- types ^ followed by the Juniperus-Agropyron community. Separation of the
Pinus-Juniperus and the Sarcobatus communities would be unreliable on this basis, except that the latter community has a much higher calcium content in the lower horizon than the former c ommuni ty-type «
It is doubtful that calcium concentrations are significant between community-typese The differences among community-types appear to be within the lim its of sampling and analysis error (Table !;)„
In most of the stands sampled the concentration of calcium increased with depth, except that the average of the Atriplex-Artemisia community indicates the reverse (Table I&)« Actually, more stands of this community conform to the usual circumstance of increased content with depth, except in a few cases the upper horizon exhibited very high concentrations, often as high as 28„2 milliequivalents «
Soil Morphological Features
The principal value of the determination of the morphological features of the soil is to gain an indication of the relative degree of development of the various so ils„ However, for the most part in the badland community-types, there is very little or no soil development.
It was found that various features, including depth and color, are quite distinctive for some of the community-types (See Appendix XI),
One of the most distinctive features found is the shallow litter layer found in the Juniperus-Qryz opsis commun! ty-type. It is the only » 8 l“
comniunitj supporting a continuous layer of surface litte r o
On the basis of color alone two community-types, the Atriplex-
Artemisia and the Rhus-Agropyron communities, can be easily distin guished from all the others « The alternating bands of gray to blue-gray
clay shales and buff colored silt beds of the Atriplex-Artemisia
community-type are very striking» Also, the almost red to reddish brown
color of the porcellanite soils of the Rhus-Agropyron community-type is
distinctive even when viewed from a considerable distance away.
Soil depth can be used as a very reliable indicator of the Artemisia-
A triplex-Agropyron and the Artemisia-Agropyron community-types » Where
colluvium deposits accumulate to depths of no greater than about 5 l
inches, the former community-type is almost exclusively found. However,
as the colluvium accumulates to greater depths of up to2h or 30 inches
thick, the Artemisia-Agropyron c ommuni ty-type is found. This relation
ship was observed in many places in the field, and in every case this
condition was consistent with the above description»
No consistent relationship was found to exist among the various
community-types on the basis of soil structure or the presence of soil
carbonates as observed in the field*
Soil samples were also analyzed for the two most extensive badland microcommunities, the Eriogonum and the Sporobolus microcommunities,
The soil was sampled at only one location for each to a depth of Ic inches, A summary of the soil characteristics of each of these micro- communities is presented in Table .82.
Table Summary of the soil characteristics of the two major badland microcommunities studied.
Soil Feature Microcommunities Eriogonum Sporobolus
Percent Sand L o 16*8 Percent S ilt SO* 7 214*8 Percent Clay U5o3 58*1: Percent Coarse Fragments lo lo Permanent W ilting Percent 8*8 15*5 Soil Reaction 8*0 7.8 Conductivity 2*9 7*6 Sodium me*/ 100 grams of soil 0*9 12*2 Calcium me*/ 100 grams of soil IloU 7*2
Physiographic Influences and Community Distribution
Physiographic effects imply the consequences of the degree of slope^
slope exposure, and the position on the slope on the distribution of
plant communities* It was found that these three factors are highly
interrelated in the badlands, where a change in any one is concomitant
with a change in the plant c ommuni ty-type * Individual stands appear to
be highly influenced by these factors, as evidenced by rather sharp
boundaries between communities with relatively minor changes in the
physiography* The topographic conditions of the study area are such that the
vegetation often takes on the appearance of strong physiographic influ
ence* The almost exclusive occurrence of badland communities on steep
south exposures, and pine woodland on north exposures strongly suggests
this relationship* Extensive expanses of grassland vegetation are -8 3 - res trie ted to nearly flat or rolling topography where physiographic influences are not very great^ and where the influence of the general climate is dominant. However, on moderate to steep slopes, and on areas where active base-leveling is occurring the general influence of climate is exceeded by the effects of physiography.
A summary of the physiographic characteristics of each plant c ommuni ty-type is presented in Figure iS, Each circle represents the range of all possible exposures, with north at the top of the circle, east on the right, south at the bottom, and west on the left. Slope degree is recorded in percent, the center of the circle representing zero percent slope, and each increment of distance from the center of the circle in any direction toward the perimeter representing increasing degrees of slope. The maximum degree of slope of 100 percent(h$ degrees) is represented on the circle perimeter. Each dot in the circle represents an individual stand at a particular sampling location. Com munity position on the slope is not represented in this figure.
Effects of Degree of Slope
It was found that a definite relationship exists between the range in the degree of slope and the occurrence of a particular community- type. Normally, as the degree of slope increases the rate of water runoff is greater, and the habitat is rendered more xeric than those of less steep slopes. Also, on steeper slopes the accumulation of soil material either through normal development or as colluvium deposits is hindered. On south exposures steeper slope surfaces receive more direct solar insolation. As the degree of slope decreases, the sun's rays reach the ground surface at a greater angle, and their drying N
W
# --
S arco b atu s A rtr iplex-A rt emis ia Art amis la-Atrlplex A rt eml s 1 a - Agropyron Agropyron
rèo
Rhus-Agropyron Juniperus-Agropyron Juniperus-Oryzopsis Pinus-Juniperus
F ig u re 15. Summary of the physiographic characteristics In terms of slope percent and exposure for each community-type. “8^“
effectiveness through heat energy incidence is less»
The summary of the data presented in Figure 1$ indicates that each
commun!ty-type has a range of slope degree within which it will occur.
The Sarcobatus community-type was sampled on bottomland fla t areas and
on slopes of over 80 percent. Presumably this commun!ty-type is found
only where a relatively considerable moisture supply is available. On
steep slopes where it occurs it was found associated with areas where
the moisture runoff received was either high, or where lateral movement
of water through lignite beds was prominent. The Atriplex-Artemisia
c ommuni ty-type occurs on the steepest slopes, every stand occurring on
slopes of over 60 percent. Some stands were observed on slopes in
excess o f 100 percent, but these were not sampled because they repre
sent a rather extreme condition.
Of particular interest in the Atriplex-Artemisia community-type is
the general appearance from a distance of parallel bands of vegetation
contouring the slope. Close examination has shown that these bands
(visible in Figure 17) of vegetation are the result of heavy stands of
Atriplex confertifolia and Artemisia tridentata growing on nearly level benches contouring the slope. These benches form as the result of
erosion of the highly erodable lignite beds, which leaves a bench of
clay material protruding out from the slope as much as several feet wide. Runoff moisture from slopes above, and water moving horizontally through the lignite beds accumulates on the benches and presents a moister habitat than the slope above and below it. These benches sup port a very dense stand of A triplex confer tifolia and Artemisia tri dentata, and in some places grasses as well. Figure l6 is a closeup =86- view of a contour bench, and Figure 17 is a view of the general appear
ance of the resulting banding effect imparted in the vegetation»
On moderately steep slopes of sandstone, clay, and silt colluvium
the Artemisia-Atriplex-Agropyron community is prominent» This community-
type was found on slopes ranging between 5h and 69 percent» On the other
hand, the closely related Ar temisi a-Agr opyr on community-type was found
on more gentle slopes ranging between 3^ and 63 percent» The r e s u lts in
Figure 15 w ill show however, that this latter c ommuni ty-type occurs more predominately on slopes of less than 50 percent»
On porcellanite caps or where porcellanite outcrops in any exten
sive areas, the Rhus-Agropyron c ommuni ty-type is found» This community
occurs on a wide range of slopes, ranging from liO to 86 percent» On
slo p es much in excess o f 85 percent porcellanite outcrops consist pri
marily of this red baked scoria» Porcellanite material usually is not
found on slopes less than Uo percent except as local benches within
larger scoria outcrops»
Moderate to moderately steep slopes are the most usual habitat of the Juniperus-Agropyron community-type» It was found on slopes ranging from 30 to 59 percent, but in most cases was found on slopes of over hO percent. The Juniperus-Oryzopsis community-type on the other hand, was found on more moderate slopes » Although the range studied is between 30 and 5U percent, by far most of the stands observed in the field are on slopes less than kO percent.
The P in u s-Ju n ip e ru s commun!ty -ty p e occurs on g e n tle slopes» W ithin any one particular stand of this community-type, the degree of slope usually varies from 0 to 30 percent. Although the range of slope •87-
F ig u re l 6 , A closeup view of a clay bench on the slope contour support ing a dense stand of Atriplex confertifolia, Artemisia tridentata, and Agropyron spicatum.
' - A.J ' >h - % - 9 '
'-4 ir'
Figure 17. A view of the general appearance of the parallel bands of vegetation on the contour of the slope supported by the clay benches. -8 8 -
encountered was 0 to 55 percent, the majority of stands are restricted
to slopes of less than 30 p e rc e n t.
The effects of slope are particularly important to the distribution
of badland c ommuni ty-type on north exposures. In a few localities the
Sarcobatus and the Atriplex-Artemisia community-types were found on
north slopes where the degree of slope was very great. These are par
ticularly conspicuous within the Pinus-ponderosa or Juniperus scopulorum
stands where steep slopes expose the interbedded shales of clay and silt
parent materials of the forest and grassland soils. It is felt that
this distribution represents a rather special case, and is not entirely
representative of the badland topogr^hy or its vegetation. For this
reason these areas were not sampled, but they are mentioned here because
this phenomenon does illustrate the importance of slope degree and its
compensating effect on exposure. In most cases these north exposure
communities are very small and play an insignificant role in depicting
the typical badland vegetation.
Effects of Exposure
On any degree of slope, the direction that the slope faces, or
exposure, greatly influences the amount of heat energy received as solar
insolation, A striking relationship was found to exist between each of
the community-types studied and slope exposure. In the Northern Hemi
sphere it can be expected that south exposures support more xeric habi
tats than north exposures. When the effects of exposure are compounded with the effects of slope gradient, the relative degree of difference between opposing exposures can be intensified. Generally west facing slopes are more xeric than east exposures, except perhaps in cases where •=>89'=’ east slopes are steeper than west exposures„
The Sarcobatus community-type is almost exclusively restricted to south exposures, except on steeper slopes where it may also be found on south-west slopeso In one location it was found on a gentle west expo sure where presumably moisture conditions were favorable„ Also, a com munity was studied on a gentle east slope in the Powder River Valleyo
Many very dense stands of this community-type were observed on the more gentle east or west exposures in the larger river bottoms « The Atriplex-
Artemisia commun!ty-type is almost exclusively restricted to south expo sures, although a few stands were found and studied on dry west exposures,
For the most part, south exposures in the badlands are steeper, and this xeric community can largely be expected to be restricted to these drier habitats. In only a very few Instances was this community found on east exposures where the degree of slope was very steep, but it was not sampled in these locations,
A wider range of exposures is exhibited by the Artemisia-A triplex-
Agropyron community than the above two community-types. It was studied and found to be very common on exposures ranging from south-east to north-west. This commun!ty-type is most common however on south expo sures, The Artemisia-Agropyron community-type is largely restricted to south facing slopes, but was observed and sampled on south-west and south-east exposures.
The Rhu s -Agr opyr on c ommuni ty-type is not as specific to exposure as most of the other community-types, and is usually found on south expo sures, As the exposure approached a west of east aspect Pinus ponderosa begins to appear in the stand, and with increased distance from the -90» south slope, the Rhus-Agropyron community eventually gives way to pine woodlando
On west and east facing slopes the Juniperus-Agropyron community- type reaches its greatest development» This community-type was never found on south slopes, but it was studied on south-west slopes. In a few places it was observed and studied on the steeper north-west expo sures, This community is found on east slopes in somewhat less quantity than on west exposures, and was sampled at one location on an east expo» sure. The Juniperu s -Or yz op si s c ommuni ty-type is the only type studied that is exclusively restricted to north exposures. Its range was found only between north-west and north-east slopes, probably reaching its greatest development on north and north-east slopes.
The Pinus - Junip eru s c ommuni ty-type was found on a wide range of exposures from north-west, south, to east slopes. Its greatest develop ment is reached however, on gentle south, south-east, or south-west exposures. On the moderately steep west or north-west exposures, local stands of this community-type are usually found.
Effects of Position on Slope
It was found that each community-type can usually be expected to occur at a particular elevation on the slopes under certain conditions.
The significance of studying position on the slope stems primarily from the possible effects of water runoff received or lost. The upper posi tions on slopes can usually be expected to be more xeric, and the lower positions more mesic* Lower slope positions usually receive more mois ture than upper slopes in terms of runoff, but these sites also receive heavy s ilt deposition and erosion damage. -9 1 -
To facilitate an understanding of the position on the slope of each
community-type, various profiles were made of some representative slopes
in the badlands* An Abney level and the 5«foot stick used in vegetation
sampling were used to collect slope percentages and horizontal distances *
Figures 18, 19, and 20, represent profiles drawn to scale showing the
positions of the various community-types relative to each other and slope
degree and position. Figures 18 and 19 are the most typical and repre
sentative profiles of the badland slopes, and Figure 20 represents a
rather special condition common only to the 0*Dell Creek area.
A diagrammatic representation of the arrangement of each community-
type on a badland slope is presented in Figure 21.
The Sarcobatus community-type was found to occupy lower slope posi
tions usually, but in a few cases it was also found on middle or upper
p o s itio n s . I t i s r a th e r uncommon to fin d S arcobatus stan d s occupying
the upper position as shown in Figure 20, but this phenomenon was
observed in some locations. The Atriplex-Artemisia community-type
occupies the middle slope position usually, however, it may frequently
be found on the lower one-third of the slope also. In a few cases it
was observed on the entire slope of isolated buttes and on steep slopes
exhibiting interbedded shales of clay and silt.
The Artem isia-Atriplex-Agropyron community-type is found almost
exclusively on middle slope positions, although in a few cases it was
observed on the lower positions as well. The Artemi sia-Agr opyr on
community—type is usually closely associated with the above community-
type, and is mostly found on lower positions immediately below it. This community-type has also been observed on middle positions in a few cases. Pine Woodland
V
Rhus-Agropyron
Atriplex-pArtemisia Rhus trilobata
Atriplex confertifolia VO PO Artemisia tridentata G rasses I V V V Porcellanite Clay shales Artemisla-Atrlplex- ^ Juniperus scopulorum Agropyron Silt shales Pinus-Juniperus Sandstone Colluvium Pinus
S cale
F eet
F ig u re l 8 . A profile of a south expos^ure near the mouth of Taylor Creek showing the position of some plant communities relative to slope and geological materials « Rhus “Agropyron
Atriplex-ArtemiRia
S arcobatus
w So, Artemis la-Atriplex Agropyron Sarcobatus vermlc- L ig n ite u la tu s Atriplex confertl- Sandstone
Artemisia tridentat' Clay shales SP Rhus trilobata i Silt shales G rasses 1 Colluvium
V V Porcellanite Agropyron S cale
F ig u re I 9. A profile of a south exposure near the mouth of Bloom Creek showing the position of some plant coumiunities relative to slope percent and geological materials. Sarcobatus vermiculatus L ig n ite A trip le x * confertifolia Sandstone A rtem isia t r l d e n t a t a Clay shales G rasses Silt shales Colluvium S arcobatus
Atrlplex-Artemisia VO I
S arcobatus
S cale
Feet A rtem isla- Agropyron
F igure 20, A profile of a south exposure near the mouth of O'Dell Creek showing the position of some plant conmiunities relative to slope and geological materials. Woodland
Agropyron
- 3800 ------
. Artemisia- 3700 - A triP le x - Agr< pyron
/ / ^ 3600
3500 \ 'hrijyie6c/
G rassland Contour line Community “boundary - - - - 33OO Elevation in feet ' Secondary drainage
Figure 21, A diagrammatic representation of the arrangement of each community-type on a badland slope. -9 6 -
The Rhüs-Agropyron community-type was sampled exclusively on upper slope positions in porcellanite material* However, in a few cases it was observed on middle positions in small localized pockets of porcellanite talus. In some areas where porcellanite talus slopes extend down the full length of the slope, this community-type was found on the entire slope as well (Figure 7).
The Juniperus-Agropyron community-type was found entirely on middle and lower slope positions. The Juniperus-Oryzopsls community-type was studied in the middle slope position at one location, but in most places it occupied most of the slope.
In most locations the Pinus-Juniperus community is situated on lower slope positions, but in some cases it is found on middle positions as well. This community-type is usually found on colluvium deposits and knobs representing remnants of sandstone outcrops at the bases of the badland slopes. However, it has also been observed and sampled on flat benches and in sandstone rimrock on middle slope positions,
A general summary of the more important environmental character istics of each community-type is presented in Appendix XII, DISCUSSION
There is a rather distinct lack of uniformity in the physiographic
and edaphic conditions in southeastern Montana which give rise to local
differences in life-form dominance of the vegetation. This is quite
strongly reflected in the badlands where frequent local changes in
physiography and geological materials result in the distribution of some
distinct plant community-types. There are certain environmental factors
which influence and control the distribution of these plant communities,
including physiographic and edaphic conditions. It has been the objec
tive of this study to isolate the various prominent environmental fac
tors in each community-type and analyze them in terms of the vegetation
cover they influence.
Each of the community-types has been characterized in terms of
botanical characteristics based on relative species abundance and fre
quency. The results indicate that each community-type is significantly
different and distinct in terms of the abundance of the dominant species
present. Field observations indicate that individual stands of each
community-type can readily be identified in terms of their botanical
composition and life-form , and the quantitative information which was
analyzed has helped to substantiate these observations. These results
show that the botanical differences in the stands of different commun!ty-
types are not due to chance factors, but rather are due to definite
envir onmental variations.
The botanical information analyzed also serves to show that the individual stands of each community-type reoccur as similar communities in many widely scattered locations wherever environmental conditions
—97"= -9 8 -
conducive to their occurrence are present. The edaphic and physio
graphic conditions characteristic of each community-type also reoccur in
similar proportions in many different locations throughout the study
area. These conditions appear to reoccur in each habitat in consistent
proportions commensurate with the ecological tolerance lim its of the
characteristic dominant and sub dominant species. In this sense there
appears to be a certain degree of uniformity among the many habitats of
each community-type. Each of the individual stands of a particular type
support the same dominant and subdominant species in about the same pro
portions of relative abundance. However, a certain amount of variation
in the absolute abundance among the various habitats for the same species
was expected and observed. This condition more closely represents the
actual situation in terms of botanical composition because a certain
degree of variation in environmental factors is common among similar
h a b i t a t s .
On the basis of the preceding analyses and observations, it is con
cluded that each of the individual stands of each community-type belong to the same natural plant association. Each community-type is considered to be an individual abstract entity composed of many individually and physically identifiable plant communities which are similar in vegetative s tr u c tu r e .
Absolute uniformity in vegetative composition or habitat environ mental conditions among widely scattered stands of a community-type was not observed. Secondary species of forbs and some grasses were found to be quite variable in terms of abundance and frequency in the various stands, and therefore were not used in characterizing the community- -9 9 -
types* Although secondary species are a natural part of the ecological
structure of each community, their role in the characterization of the
community is rather limited. It is the dominant species which gives the
community its character in terms of life-form and ecological stability
(Clements 1936). Therefore, only those species which appeared to main
tain the maximum degree of dominance from one sim ilar habitat to another
were used as indicators of community structure.
Only the dominant and subdominant species taken collectively were
used as indicators of environmental conditions within each community-
type, Although some dominant species have been shown to be poor indi
cators of certain conditions, some environmental factors are more
specifically lim iting. The incidence of species overlap among habitats
of various community-types is highest in the secondary group of species.
The dominant and subdominant species were found to be the most reliable
indicators, and overlapping into other community-types is usually less
pronounced. In many cases the occurrence of a dominant of one community-
type in another type is restricted to a rather minor ecological status.
Only where community-types are very closely related in terms of habitat
conditions do the same species serve as dominants or subdominants in
each ty p e .
These results appear to be substantiated by the observations of
Clements (1928, 193^4) and Sampson (1939) that the plant community is the best indicator of environmental conditions. In terms of the community as an Indicator, the reactions of many species to the continuous varia tions in the environment are responsible for a particular community structure. In this sense, the character of the vegetation as a whole -100-
reacts rather significantly to changes in the environment. Although
adjacent stands on slightly different habitats may support many of the
same species, the structure of the vegetation in each in terms of rela
tive abundance and frequency is different. Thus, the character of a
plant community is not based purely on species presence or absence, but
primarily on structure as expressed through relative species abundance.
It was found that the Sarcobatus community-type is tolerant of, but
not entirely restricted to soils of high soluble salt and sodium concen
trations, This community-type has been found on soils ranging from very
low to very high soluble salt concentrations, and as such is probably
not a good indicator of them. These results are similar to those found
for Sarcobatus vermiculatus by Hayward and Wadleigh (19li9) and Gates
e t a l , ( 1956 ), The Sarcobatus community-type reaches its greatest
development on areas where moisture is readily available. The extensive
stands of this community-type in the bottomlands of the Powder and
Tongue Rivers indicate that in areas with a high water table, or where
substantial quantities of moisture are available from runoff, Sarcobatus
vermiculatus attains its highest abundance. These conclusions follow
those of Shantz and Piemeisel (19liO), who found the Sarcobatus associa
tion of the Escalante Valley to be restricted to bottomlands and to
mouths of drainages.
On the steep south facing slopes of the badlands the Sarcobatus
community-type appears to be restricted to areas where subsurface mois
ture moves out to the surface in substantial quantities. In these areas
high concentrations of salts and sodium accumulate in the soil surface,
A high degree of solar insolation through evaporation often helps to “ 1 0 1 “
create a thin surface crust in the soil containing visible crystals of
salt. The less salt-tolerant species of other community-types cannot
successfully compete with those of the Sarcobatus community on these
areas. It appears that the occurrence of lignite seams on the slopes is
a prerequisite to the establishment of this community, presumably through
their role as aquifiers.
The degree of variation in the abundance of secondary species among
stands was greatest in this community-type. Where salt concentrations
are very high, Sarcobatus vermiculatus and Distichlis stricta are the
primary members of this community. In relatively non-saline soils,
Sarcobatus vermiculatus s till maintains dominance, but Artemisia triden-
tata becomes a noticeable sub dominant. Thus, it appears that Sarcobatus vermiculatus maintains its dominant status in the community under condi
tions where competition is lacking. It is probably not a successful
competitor on non-saline soils, but because of its salt tolerance it
achieves dominance under saline conditions. This observation is sub
stantiated by the studies of Gates et al, (19^6), Shantz and Piemeisel
(ipliO), and Hayward and Wadleigh ( 19^9 ).
The A triplex-Artem isia community-type was found to be entirely restricted to outcrops on very steep dry slopes of interbedded shales of clay and silt. It is apparent that the degree of slope is probably the most critical factor influencing the distribution of this community- type. The exposed surfaces of bedded geological materials outcrop at the surface only on very steep slopes, and are usually restricted to south exposures. Exposure or position on the slope are not critical as evidenced by the presence of this community on all positions and —1,02—
exposures, including north where the slope gradient was sufficiently
steep to preclude soil development or the accumulation of talus.
These extreme environmental conditions render this community-type
the most xeric in the badlands of southeastern Montana* The range in
the degree of slope observed in the field is from 65 to well over 100
percent. Presumably a very large percentage of the precipitation
received in this commun!ty-type never is absorbed into the soil, but is
lost as runoff. Several observations of moisture penetration following
rain storms indicate that moisture probably seldom penetrates greater
than 3 inches in the clay shales, and 5 inches in the silt, Billings
(I 9U9) and Shantz and Piemeisel (19^0) have found Atriplex confertifolia
to be very drought resistant in the Great Basin region.
On extremely steep slopes the abundance of Artemisia tridentata
very noticeably decreases, and that of the grasses diminishes to almost
complete absence. The greatest abundance of species cover in this com
munity-type occurs on parallel clay benches that contour the slope below
eroded out lignite beds. The aquiferous nature of these lignite beds
undoubtedly is a contributing factor to the increased density of plant
cover. Root penetration studies made in the field indicate that the tap
roots of mature Atriplex confertifolia and Artemisia trldentata plants
extend to depths of six feet or more. In most cases vertical penetration terminates within a lignite seam where extensive lateral root development
o c c u rs.
Subsurface movement of water in this community-type may not be as great as in the Sarcobatus community, as evidenced by the rather low to moderate concentrations of soluble salts and sodium near the surface. -103-
Both of the dominant species, and particularly Atriplex confertifolia, are moderately tolerant of saline soils. Apparently the two dominant species are primarily restricted to the beds of clay shales, but roots penetrate both silt and clay material. It was never fully resolved just which bed, if any, from which the dominant species are more frequently grow ing.
The principal environmental factor controlling the distribution of the Artemisia-Atriplex-Agropyron and the Artemisia-Agropyron communities is the presence of talus material on the badland slopes. The only con sistent environmental factor that was found associated with both of these communities is the presence of talus slopes. "Where the talus is relatively shallow on steeper slopes, the Artemisia -Atrip 1 ex-Agr opyr on community predominates. As the slope becomes more gentle and the accum ulation of talus becomes deeper the Artemi si a-Agr opyr on community gains predominance.
The Artemi s i a -A tr iplex-Agr opyr on community-type is the most abun dant community occurring in the badlands. On every major badland slope in the study area this community-type was observed, and usually found to be the major community present.
From the analysis of the data it is apparent that Atriplex confert ifo lia is a subdominant in the Artemisi a-Atrip lex-Agr opyr on community as influenced by relatively drier conditions and higher salt and sodium concentrations. However, as the slope degree becomes less steep and the depth of the talus increases in the Artemisia-Agropyron community-type, the amount of runoff received increases with a consequent leaching of salts. Apparently the environmental changes in this case become more -lo ii-
favorable to Artemisia tridentata and Agropyron spicatum which are
successful in maintaining dominance to the exclusion or reduction of
Atriplex confertifolia.
The Artemisia -Ag r opyr on community-type is usually found immediately
above and adjacent to the grasslands of the stream terraces at the base
of badland slopes. Frequently there is a lack of a distinct boundary
between this community-type and the grassland. The ecotone between the
two is often on gentle slopes, and is composed of species from both
types. Thus, it is not uncommon to encounter small and limited stands
of Bouteloua curtipendula, Stipa comata, and S. viridula in the
Artemisia-Agropyron community-type.
A coarse textured soil coupled with a high percentage of coarse
fragments appears to be the principal factor influencing the distribu
tion of the Rhus-Agropyr on communi ty-type. This community reaches its
greatest development on porcellanite slopes where coarse fragments may
constitute as much as 1^0 percent of the soil volume. This community-
type is restricted to moderately steep slopes on south exposures composed
of red porcellanite.
Where the porcellanite material makes contact with the clay and silt beds below, the abundance of Rhus trilobata is greatest. The clay and
s ilt materials are relatively impervious to water penetration, and may
act almost as a hardpan to the rapid infiltration of water through the porcellanite. At this contact there is evidence that some water moves horizontally to the surface through the porcellanite. This character istic gives the community a relatively sharp boundary because Rhus trilobata is very dense at this contact zone. With increasing distance - lo g -
ap the slope away from the general contact zone, the abundance of Rhus
trilobata and Agropyron spicatum decrease. This characteristic often
gives this community the appearance of occurring as a narrow band along
the contour of the slope following the contact zone between porcellanite
and clay shale.
The la c k of tr e e s in th is communi ty -ty p e on south exposures i s
probably due to the high incidence of solar insolation. Scattered plants
of Pinus ponder os a are found on east and west exposures within this com
munity, and on north-west and north-east exposures the Rhus-Agropyron
communi ty-type gives way to pine woodland. In areas on south slopes where subsurface moisture is relatively high some mesic herbaceous and
shrub species have been found to move into the community. At one loca
tion a dense stand of Elymus cinereus was found with Rhus trilobata,
Ribes cereum was found in the stand in the East Fork of Hanging Woman
C reek,
The distribution of the Juniperus-Agropyron and the Juniperus-
Oryzopsis community-types appears to be controlled by the influence of exposure. The former community-type is restricted to west, south-west, or east and south-east exposures of badland topography, and the latter community-type to north slopes associated with pine woodland. The
Juniperus-Agropyron community-type is commonly found in the channels of side drainages that flow from badland slopes. Also, this community is frequently found extending out into the grasslands in the channels of these drainages. Its greatest development is reached on west and east exposures of badland slopes, but it has never been observed on south ex p o su res. - 106 -
The Junip era s -Agropyr on commimi ty-type is the second most abundant
type in the badlands, and it is estimated to cover 20 percent of the badland area* It is one of the more mesic communities studied* With
slight changes in exposure to a more xeric aspect, its boundaries are very sharp and distinct. On drier sites stands are composed of about
300 trees per acre, but on the moister sites this increases to about
600 trees per acre.
The Ju n ip e ru s- O ryzopsis communi ty -ty p e i s c lo s e ly r e la te d to the
Juniperus-Agropyron community in terms of the common species in each, except for the presence of Oryzopsis mi cran th a in the former community.
The distribution of this community is exclusively restricted to moist north exposures. The variation in the soil factors indicate that they are not important in influencing the distribution of this community- ty p e.
The principal factors controlling the distribution of the Pinus-
Juniperus communi ty-type appear to be its position on the slope and the occurrence of sandy knolls at the base of badland slopes. Apparently this community-type is restricted to gentle slopes, but exposure is not as specific. At the base of steep badland slopes this community-type receives a substantial amount of water runoff originating from the steep slopes above. Also, the rapid infiltration of precipitation into the sandy soil gives the tree species a competitive advantage over the relatively shallow rooted herbaceous and shrubby vegetation.
With an increase in the degree of slope the effects of exposure become pronounced on the distribution of the Pinus»Juniperus community.
In coarse textured soils on steep slopes on south exposures Rhus- <*•107 •“
trilobata assumes dominance, and Pinus ponderosa w ill not reassume dom
inance unless the exposure changes to north-west or north-east. The
factors of physiography and soil texture apparently are dominant in
influencing the distribution of this community.
Each of the community-types appears to be associated with certain
other types, although no generalization can be definitely made in this
case. The matter of community association is primarily controlled by
the distribution of topographical features. On long slopes with a wide
range in geological materials, patterns of various community-types are
arrayed in striking conformity with local habitat conditions. In the
most usual sense certain community-types are apparently associated with
certain other community-types as adjacent stands on the badland slopes.
However, it is not uncommon to find stands of any one of the community-
types occurring as an isolated community, completely disjunct from any
other badland community. This is particularly common on slopes of
rather small isolated buttes or on restricted and slightly elevated
remnants of badland topography which are surrounded by grassland or pine
woodland vegetation.
The Sarcobatus and the A triplex-A r temisia community-types are
almost always adjacent to each other. Most commonly the Sarcobatus com munity is below the Atriplex-Artemisia community, or beside it at the same elevation. It has been observed that the Sarcobatus community occurred above the latter community, but this is a rather special case.
In areas where the Sarcobatus community is absent, there is a c h a r a c te r is tic sequence of communities on th e slo p e very commonly observed throughout the study area. Where a porcellanite cap is lacking. -1 0 8 -
as on buttes and flat-topped mesas, the Atriplex-Artemisia community
commonly occupies the upper one-third of the slope. Immediately below
this there may be a thin or moderately thick bed of outcropping sand
stone, below which the greatest part of the slope is occupied by the
Artemisia-Atriplex-Agropyron community-type. The colluvium material
supporting this community is primarily derived from the weathering of
the massive outcrops of sandstone. The lower one-fifth to one-third of
the slope is occupied by the Artemisia-Agropyron community-type.
The Rhus-Agropyron communi ty -ty p e i s a s so c ia te d on th e upper end
with Pinus ponderosa stands which occupy north exposures immediately
over the crest of the badland slope. Below the Rhus-Agropyron commun
ity, and adjacent to it, is usually located the Atriplex-Artemisia com
munity on south exposures. On east and west exposures the Juniperus-
Agropyron community commonly occurs immediately below the Rhus-
Agropyron community. On slides composed of talus porcellanite this
community may occur as an isolated stand (Figure 7).
The Juniperus-Agropyron community-type is almost always associated
with the Artemisia-Atriplex-Agropyron communi ty-type. Usually the latter
community extends around the slope to the south-west or south-east where
the Juniperus-Agropyron community gains prominence. In a few places
th is community i s also associated with the Pinus-Juniperus community on
south-west or south-east slopes.
The Juniperus-Oryzopsis communi ty-type is always associated with pine woodland, or is an isolated community on north slopes,
Pinus-Juniperus stands are either isolated on colluvial knolls and remnants of sandstone outcrops at the base of badland slopes, or -109-
occasionally associated m_th the Juniperus -Agropyron or the Artemisia-
Atriplex-Agropyron communities. In some places the latter community,
or the Artemis ia-Agr opyr on community extends down the slope and borders
on these colluvium knolls.
There is some indication that the effects of climatic drought may
significantly affect the long term distribution of Pinus ponder os a and
Juniperus scopulorum. In the eastern portion of the study area near the
Powder River there was found extensive areas supporting stands of young
Juniperus scopulorum, but only dead snags of Pinus ponderosa. No evi
dence of charcoal was found to indicate fire as the cause of this
phenomenon. A very apparent lack of Pinus ponderosa seedlings indicate
that some historical change has taken place in the site. It is felt
that the possibility of drought as a factor cannot be entirely eliminated
as the cause. The effects of drought on mixed prairie vegetation has been extensively discussed, primarily by Coupland (19?8, 1 9 5 9 Albert
son and Weaver (I9U6 ), Ellison and Woolfoik (1937)> and Borchert (1950).
There are certain vegetation-environment relationships which indi
cate that some inference can be made relative to the probable geographic
affinities of the flora in the badlands. It appears that most of the
secondary species encountered, primarily the herbaceous vegetation, belong to the regional grassland climax of the northern Great Plains
(Coupland 1950, 196 I, Larson and Whitman 19lj-2, Quinnild and Cosby 1958,
Clements 193U> Weaver and Clements 1938, Albertson and Weaver I 9I46 ).
Also, there is abundant evidence that the majority of the shrub and tree species have centers of origin far removed from southeastern Montana
(Potter and Green 196k, B eetle 19 60 , Reed and Peterson I 96 I, Gates et al. -110-
1956, Billings 191(9).
The distribution of the woody species in southeastern Montana
appear to be controlled by physiographic features of the landscape. The
principal woody species, most of which also occur on the badland topog
raphy, appear to have originated in the Rocky Mountains, the Black Hills,
and the Great Basin. The principal Rocky Mountain species include Pinus
ponderosa, Juniperus scopulorum, Festuca idahoensis, and Rhus trilobata.
It has been suggested that Pinus ponderosa represents a relict of the
Black Hills region, but Potter and Green (1961;) discount this hypothesis
on the basis that evidence is lacking for post-Pleistocene migration of
this species in western North Dakota.
Of the climax formations of North America, Weaver and Clements
(1938) indicate that Atriplex confertifolia, Artemisia tridentata,
Sarcobatus vermiculatus, and Eurotia lanata are part of the climatic
climax only in the salt desert and northern desert shrub regions of the
Great Basin. It is evident from the literature that these species
reach their greatest ecological development in these regions (Gates et
a l. 1956, Fautin 19l;6, Stewart et al. 19l|0, Billings 19l;9, Fireman and
Hayward 1952, Shantz and Piemeisel 19l;0).
Although these same woody species have been reported to occur on
the buttes of western North Dakota by Judd (1939) and Whitman and Hanson
(1939)f it is apparent that they are not representative of the climax of
the northern Great Plains region. It is apparent that physiographic
conditions are the principal factors controlling the distribution of the vegetation in the badlands. Relative to the tree vegetation and Rhus trilobata, it is apparent that their distribution is restricted to the - I l l - mesic sites as controlled by exposure and soil texture* However, in the case of the shrub dominants native to the Great Basin, their distribution is restricted primarily to xeric sites. Although the precipitation of the study area is almost double that of the Great Basin region, the effects of an extreme slope gradient coupled with predominantly south
exposures and relatively heavy soils are sufficient to compensate for
the general climatic disparity. High concentrations of soluble salt
accumulations in the soil surface coupled with increased solar insola
tion and high evaporation create an environmental situation very similar
to the dry desert regions. Soil and vegetation data of this study appear
to be commensurate with that reported for these species in the Great
Basin (Gates et 19^6, Fautin 19^:6, Stewart et al, 191:0, Shantz and
Piemeisel 19LO, Billings 19U9). SUMMARY AM) CQNCIUSIGNS
The vegetation occurring on the badland topography of southeastern
Montana is composed of seven readily distinguishable plant community-
ty p e s, Each communi ty -ty p e occurs as many w idely s c a tte re d stands on
characteristic habitat conditions throughout the badlands of the study
area. It was the objective of this study to characterize each community-
type in terms of its botanical characteristics and associated environ
mental factors.
The stick-line interception sampling technique was used to deter
mine the relative abundance and frequency of each community-type. Soil
samples were collected from the upper and lower horizons of each
community-type, and were analyzed for soil texture, percent coarse frag
ments, permanent wilting percentage, pH, electrical conductivity, and
extractable sodium and calcium. Profile descriptions were also made for
each community-type. Physiographic information collected includes per
cent slope, slope exposure, and the community's position on the slope.
The various badland community-types studied are the Sarcobatus,
A triplex-Artemisia, Artemisia-Atriplex-Agropyron, Artemisia -Agropyron,
Rhu s -Agr opyr on, Juniperus-Agropyron, and the Pinus-Juniperus communities.
An additional communi ty-type was included because of its close relation ship with the J unip er us -Agropyr on community. This communi ty-type, the
Juniperus-Oryzopsis community, is never found on typical badland topog raphy, Several microcommunities were also observed and studied, the two most prominent ones being the Eriogonum multi ceps and the Sporobolus cryptandrus microcommunities.
In general, the results of the botanical studies indicate that the
.1 1 2 - -113- various cornmuni ty-type s are significantly different from each other in
terms of the kind and abundance of the dominant species* It follows
that the observed differences among the community-types are due to some
other factor or group of factors other than chance or sampling errors.
Thus, it is concluded that various environmental factors are influential
in controlling the distribution of the plant community-types of the bad
lands in southeastern Montana,
It has also been shown that the differences in abundance between the
various dominant and sub dominant species within each communi ty-type are
significant. There is a strong element of sim ilarity between stands of a
given communi ty-type. The relative abundances of the major species and
the resulting relationships were tested statistically and found to sup port this conclusion.
It is apparent from the analysis of environmental factors that physiographic conditions, in so far as they influence the availability
of soil moisture, are of prime importance to the distribution of the various community-types. Soil factors appear to be rather secondary in influencing community distribution, however certain edaphic conditions were found to be important. These include soil texture, percent coarse fragments, soluble salt concentration, and sodium content.
The Sarcobatus community-type was found to be tolerant of, but not restricted to soils of high salt and sodium concentrations. It reaches its greatest development in bottomlands with a high water table or that receives a substantial runoff from adjacent slopes. On steep slopes it was found only where there was sufficient movement of subsurface water out to the surface to increase the accumulation of salts and sodium in the upper two feet of the soil. The Atriplex-Artemisia community was
also found to be relatively tolerant of saline and high sodium soils, but not to the extent that the Sarcobatus community was observed. The
Atriplex-Artemisia community is entirely restricted to dry very steep
slopes where the geological strata outcrop at the surface. The greatest
abundance of Atriplex confertifolia and Artemisia tridentata occurs on
horizontal benches formed as the result of erosion of lignite seams. The beds of lignite coal are believed to play a very significant role in the
distribution of both of the above community-types through their capacity
to serve as aquifiers.
Talus slopes of sandstone fragments, clay shales, silt, and silt-
stone are prerequisite to the occurrence of the Artemisia-Atriplex-
Agropyron and the Artemisia-Agropyron communities. Accumulations of
talus usually develop on moderate slopes below massive outcroppings of
sandstone. The former communi ty-type occurs on the drier and steeper
slopes with the shallower talus accumulations. Usually, immediately below this community, where the slope is gentler and the talus accumu lates to greater depth, the Artemisia-Agropyron community occurs. This communi ty-type presumably receives a greater amount of runoff, and hence is the more mesic site of the two. This provides for greater leaching of salts and sodium, and provides more moisture for plant growth. It is felt that these factors allow for the successful competition of Artemisia tridentata and Agropyron spicatum with Atriplex confertifolia, with the result that the latter species is eliminated or reduced to a minor status in the community structure.
Coarse textured soils on south facing porcellanite slopes support -115-
th e Rhü 3-Agr opyr on communi ty -ty p e . The ra p id i n f i l t r a t i o n of m oisture
into the soil, coupled with high solar insolation on south slopes allows
Rhus trilobata to successfully compete with herbaceous and tree vegeta
tion, Stands of Rhus trilobata reach their greatest development in the
contact zone between porcellanite and interbedded shales of clay and
s i l t .
The closely related Junip eru s -Agr opyr on and Juniperus-Oryzopsis
communities are restricted to moist sites. The former community is
restricted to the badland topography, and the latter to moist micro
habitats on north slopes. The former community-type is found only in
drainage channels on south slopes or on gentle east and west facing
slopes of the badlands. The latter community-type is found in associa
tion with pine woodlands on north slopes, and is never found in the bad
lands, The chief difference between these two community-types is the
exclusive and conspicuous occurrence of Oryzopsis micrantha in the
J uni peru s-Or yz opsis community-type,
Sandy textured knolls representing colluvium deposits or remnants
of sandstone outcrops at the base of badland slopes support the Pinus-
Juniperus community-type. Presumably the lower incidence of solar
radiation and the increased amount runoff received on these sites are
sufficient to support this community. Apparently the degree of slope is
most important in limiting its distribution on south exposures. On south facing slopes with a slope gradient greater than 30 percent the Pinus-
Juniperus community gives way to the Artemisi a-Atrip lex-A gr opyr on or the
Rhus-Agropyron community.
It is concluded that the vegetation of the badlands of southeastern -1 1 6 -
Montana does not represent the climax for the study area. It is felt that the dominant ecological influence of climate w ill in time, through base leveling, create habitats unsuitable to the present vegetation, and more suitable to the regional mixed prairie grassland climax. The pres ent vegetation of the badlands represents extensions of vegetation with several different geographic affinities including the Black Hills,
Rocky Mountains, and the salt desert of the Great Basin. The dominant environmental influences controlling the distribution of the badland vegetation are physiographic factors which compensate for the regional climate, and create a complex of habitat conditions suitable for this heterogeneous vegetation. These compensating features of the landscape can be regarded as a passing-time phase in the development of the climax vegetation.
In terms of livestock and game use, the Artemisia-Agropyron and the Rhus-Agropyron community-types are probably the most important of the badland community-types. These two communities appear to be the only ones suitable for use in terms of abundance of feed and accessibil ity , Although other community-types support palatable species, the problems of accessibility preclude extensive grazing use of them.
The badlands are probably best suited to use by game. Field obser vations indicate that Rhus trilobate is grazed primarily by deer. The
Artemisia-Agropyron community supports the densest stand of grasses, and presents the most accessible topography in the badlands. In most cases this community-type is adjacent to the grassland types immediately below the badland slopes, and supports many of the same species.
Perhaps the most important implications of the badlands to the land -117- manager are those of watershed management. In this respect, direct application of runoff control measures or the construction of erosion control structures to the steep slopes would probably prove impractical.
It is suggested that the effects of water movement and soil erosion be controlled from the standpoint of sound grazing management principles.
Through the regulation of grazing and sound management applications, the grassland vegetation immediately adjacent to the base of the badland slopes should be maintained at maximum vigor and density to aid in desilting and controlling the force of runoff. It is recommended that only limited grazing in the spring and fall be permitted on these grass land terraces.
The rugged terrain of the badlands offer some measure of shelter to livestock during severe storms, and some seep areas where high salt con centrations accumulate on the soil surface offer natural licks. LITERATURE CITED -1 1 9 -
Albertson, F, W. and J. E. Weaver, 191^6, Redaction of angrazed mixed prairie to short grass as a result of drought and dust, Ecol. Monog, 16 : l4-ii9-U63.
Anderson, E. W, 1956. Some soi1-plant relationships in eastern Oregon, J o u r. Range Mgmt. 9r 171-175.
Anderson, K, L, and C. L, Fly, 1955. Vegetation-soil relationships in Flint Hills bluestem pastures. Jour, Range Mgmt, 8: 163 -I 69 .
Arnold, J. F ., D. A, Jameson, and E, H, Reid, I 96U. The piny o n -ju n ip er type of Arizona; effects of grazing, fire, and tree control, U. S, Forest Service, Prod, Res, Report No, 6U, 28 pp.
Ayyad, M, A. G, and R, L, Dix. 196ii, An analysis of a vegetation- microenvironmental complex on prairie slopes in Saskatchewan, Ecol, Monog , 3ht U2I-UU2 .
Beadle, N, C, W, 1951. The misuse of climate as an indicator of vegetation and soils. Ecology 32t3U3-3U5.
Beetle, A. A, i 960 , A study of sagebrush: the section Tridentatae of Artemisia. Univ. of Wyoming, Agric, Expt. Stat, Bull. 368 , 83 pp.
B illings, W. D, 191:9. The shads cale vegetation zone of Nevada and eastern California in relation to climate and soils. Amer, Midland Nat, 1:2: 87-109.
B lack, C, A, 1957 . Soi1-plant relationships, John Wiley and Sons, Inc. New Y ork, 332 pp.
Bolen, E, G, 1961:. Plant ecology of spring-fed marshes in western Utah* Ecol, Monog, 3hr 11:3-166,
Booth, W. E, 1950, Flora of Montana, Part I. Conifers and monocots, Montana State College, Bozeman, 232 pp.
______and J, C, Wright, 1962, Flora of Montana, Part II, Dicotyledons. Montana State College, Bozeman, 280 pp.
Borchert, J, R. 1950. The climate of the central North American grass- ^ land. Ann, Assoc, Amer, Geog, 1:0: 1-39.
Bouyoucos, G, J. 1936, Directions for making mechanical analysis of soils by the hydrometer method. Soil Sci. 1:2: 225-229.
Box, T, W, 1961 , Relationships between plants and soils of four range plant communities in south Texas, Ecology 1:2:791:-810.
Buck, P . I 96 I:. Relationships of the woody vegetation of the Wichita Mountains W ildlife Refuge to geological formations and soil types. Ecology 1:5: 336-3W:, -1 2 0 -
Buckman, H. 0, and N. C. Brady. I 96 O. The nature and properties of soils. Sixth Edition. Macmillan Co, New York, ^6? pp.
Burbanck, M. P. and R. B, P latt. 1961;, Granite outcrop communities of the Piedmont Plateau in Georgia. Ecology 292-306.
Canfield, R. H, 19l;l. Application of the line interception method in sampling range vegetation. Jour, For. 39: 388-391;•
Carpenter, J. R, 1936. Concepts and criteria for the recognition of communities. Jour, Ecol, 21;: 285-289•
Clements, F. E, 1928, Plant succession and indicators, H. W. Wilson Co. New Y ork. 1;53 pp.
. I 93I;. The relic t method in dynamic ecology. Jour, Ecol, 22; 39-68,
, 1936 . Nature and structure of the climax. Jour, Ecol, 21;s 252-
Cole, L, C, 19h9* The measurement of interspecific association. Ecology 30r 1;11-U29.
Cook, C, W. and R, Hurst, I 962 . A quantitative measure of plant associa tion on ranges in good and poor condition. Jour, Range Mgmt, l5: 266 - 273 .
Cooper, C. F . I961 , Pattern in ponderosa pine forests. Ecology 1;2: 1;93- 199.
Cottle, H, J, 1932, Vegetation on north and south slopes of mountains in southwestern Texas, Ecology 13:121-131;.
Coupland, R. T, 1950, Ecology of mixed prairie in Canada. Ecol. Monog, 20r 271 - 315.
______, 1958, The effects of fluctuations in weather upon the grass lands of the Great Plains, Bot, Rev, 2hs 273-317,
______, 1959. Effects of changes in weather conditions upon grasslands in the Northern Great Plains, in Grasslands, Publ. 53. Amer, Assoc, Advan, Sci. Washington, D. C, pp. 291-306,
______, 1961 , A reconsideration of grassland classification in the Northern Great Plains of North America, Jour. Ecol, 1;9: 135-167,
Crockett, J. J, 1961;, Influence of soils and parent materials on grass lands of the Wichita Mountains W ildlife Refuge, Oklahoma, Ecology 1;5: 326 - 335. -121-
Gumming, K, J . 19^3* The e f f e c t of slo p e and exposure on range veg eta tion in desert grassland and oak woodland area of Santa Cruz County, Arizona, Jour, Range Mgmt, 6r 219.
Daubenmire, R, 19^2, Forest vegetation of northern Idaho and adjacent Washington, and its bearing on concepts of vegetation classifica tion, Ecol, Monog, 22r 301-330.
______, 19^6, Climate as a determinant of vegetation distribution in eastern Washington and northern Idaho, Ecol, Monog, 26; 131-lïb,
. 1959. Plants and environment. Second Edition, John Wiley and Sons, I n c , New York, i;22 pp,
______and A, W. Slipp. 19U3. Plant succession on talus slopes in northern Idaho as influenced by slope exposure, Torrey Bot, Club Bull, 70: U73-U80,
Davis, L, E, 19ii3. Measurements of pH with the glass electrode as affected by soil moisture. Soil Sci, 56: i;05-U22,
Dightman, R. A, 1963. Climate of Powder River County, Montana, U, S, Dept, Commerce, Weather Bureau,
Dix, R. L, 1958. Some slope-plant relationships in the grasslands of the L ittle Missouri Badlands of North Dakota, Jour, Range Mgmt, 11: 88-92,
Driscoll, R. S. I 96U, A relict area in the central Oregon juniper zone. Ecology h$: 3^5-353.
Ellison, L, I 9U9. Establishment of vegetation on depleted subalpine range as influenced by microenvironment, Ecol, Monog, 19: 95-121,
, 195U, Subalpine vegetation of the Wasatch Plateau, Utah, Ecol, Monog, 2k: 89-18U,
, i 960 . Influence of grazing on plant succession of rangelands, Bot. Rev, 26: 1-78,
and E, J, Woolf oik, 1937. Effects of drought on vegetation near Miles City, Montana, Ecology 18; 329-336,
Fantin, R, W, 19L6, Biotic communities of the northern desert shrub biome in western Utah, Ecol, Monog. 16: 251-310,
Fireman, M, and H, E. Hayward, 1952, Indicator significance of some shrubs in the Escalante Desert, Utah, Bot, Gaz, III 4.: 1L3-155.
Fox, R. E, 1957 . A proposed method for estimating reduction of avail able moisture in saline soils. Soil Sci, 83: Lb9-L5^^ -1 2 2 -
Gates, D. H,, L. A. Stoddart, and C. W. Cook. 19$6. Soil as a factor influencing plant distribution on salt-deserts of Utah. Ecol. Monog. 26: 1^5-175.
Gleason, H, A. 1939. The individualistic concept of the plant associa tion, Amer, Midland Mat, 21: 92-110.
Greig-Smith, P. 19^7, Quantitative plant ecology. Academic Press Inc, New York. 198 pp.
Hanson, H, C, 19^8, Principles concerned in the formation and classifi cation of communities, Bot. Rev. 21;: 65-125.
and E. D. Churchill, I 96 I. The plant community. Reinhold Publ, Corp. New York. 218 pp.
______and ¥. Whitman. 1937. Plant succession on solonetz soils in western North Dakota, Ecology 18: 516-522.
______a n d ______, 1938, Characteristics of major grassland types in western North Dakota. Ecol. Monog, 8: 57-llL.
Hayward, H. E. and C. H. W adleigh, I 9I4.9. Plant growth on saline and alkali soils, Advan, Agron, 1: 1-38.
Hitchcock, A. S, 1950, Manual of the grasses of the United States. U. S, Dept, Agric. Mise, Publ. 200, 105l pp.
Jackson, M. L, 1958, Soil chemical analysis, Prentice-Hall, Inc, Engle wood C liffs, Û98 pp.
Jameson, D, A., J. A. Williams, and E, W. Wilton. I 962 . Vegetation and soils of Fishtail Mesa, Arizona, Ecology h3: i;03-hlO,
Judd, I, B. 1939. Plant succession on scoria buttes of western North Dakota, Ecology 20; 335-336.
Kelley, A. P. 1922. Plant indicators of soil types. Soil Sci. 13: Ull- 123. Larson, F. and W. Whitman, 19l|.2, A comparison of used and unused grass land mesas in the badlands of South Dakota. Ecology 23: L38-1:L5.
Looman, J, I 963 . Preliminary classification of grasslands in Saskatch ewan. Ecology Wi: 15-29,
Magistad, 0. C, 19^5, Plant growth relations on saline and alkali soils, Bot. Rev, 11; 181-230.
Mason, H. L, 19^6. The edaphic factor in narrow endemism. I. The nature of environmental influences, MadrorTo 8; 209-226. -123-
McMinrij, R. 19$2. The role of so il drought in the distribution of vegeta tion in the northern Rocky Mountains. Ecology 33: 1-1$.
Morris, M. S. 19L6. An ecological basis for the classification of Mon tana grasslands. Proc* Mont. Acad. Sci. 6: i|l-i|ii.
Nichols, G. E, 1923a. A working basis for the ecological classification of plant communities. Ecology i;: 11-23.
. 1923b, A working basis for the ecological classification of plant communities. Part II. Ecology I4: l$i;-179.
Nixon, E, S, 1961t. Edaphic responses of Lupinus texensis and Lupinus subcarnosus. Ecology It$: lt$9-i|69.
______and C. McMillan. 1961:. The role of soil in the distribution of four grass species in Texas, Amer. Midland Nat. 71: llit-lltO,
Pase, C. P. 19$8. An ecological study of sagebrush, Artemisia tridentata N utt,, in western Montana. M.S. thesis. Montana State University 6$ pp.
P assey , H. B. and V. K. H ugie. I 963 . Some plant-soil relationships on an ungrazed range area of southeastern Idaho, Jour, Range Mgmt, I6 ; 113- 11 8.
P a tte n , D. T, I 963 . Vegetational pattern in relation to environment in the Madison Range Montana. Ecol. Monog. 33: 37$-lt06.
Phillips, J, 193$. Succession, development, the climax, and the complex organism. II. An analysis of concepts. Jour. Ecol, 23: 210-21:6.
Potter, L. D. and D, L. Green. I 96 L. Ecology of ponderosa pine in western North Dakota. Ecology i|$: 10-23.
Poult on, C, E. and E. ¥. Tisdale. I96 I. A quantitative method for the description and classification of range vegetation. Jour, Range Mgmt. Hi: 13- 21.
Quinnild, C, L. and H. B. Cosby. 19$8. Relicts of climax vegetation on two mesas in western North Dakota. Ecology 39: 29-32,
Reed, M. J. and R. A. Peterson. I 96 I. Vegetation, soil, and cattle responses to grazing on northern Great Plains range. U, S. Dept. Agric. Tech, Bull, No, 12$2. 79 pp.
Richards, L. A. 191:7. Pres sure-membrane apparatus construction and use. A g ric . Engin. 28: 1:$1-1:$L, 1:60.
and L. R, Weaver. 191:3. Fifteen-atmosphere percentage as related to the permanent wilting percentage. Soil Sci. $6: 331-339. Rickard, W, H, 1965* The influence of greasewood on soil-moisture pene tr a tio n and s o i l chem istry. Northwest S c i, 39s 36-14.2,
Sampson, A. W, 1939. Plant indicators-concept and status, Bot, Rev, $: 155-206.
, 1959. Range management: principles and practices. John Wiley and Sons, Inc. New York, 570 pp.
Schuchert, C, and C, 0. Dunbar, 19^5. A textbook of geology. Part II, H istorical geology. Fourth Edition, John Wiley and Sons, Inc. New York, 5UU pp.
Shantz, H, L, and R, L, Piemeisel. 19^0, Types of vegetation in Escalante Valley, Utah, as indicators of soil conditions, U. S, Dept, Agric, Tech, Bull, No, 713.U6 pp,
Smoliak, S, 1956, Influence of climatic conditions on forage production of shortgrass rangeland. Jour, Range Mgmt, 9? 89-91.
Snedecor, G, W, 1956, S tatistical methods, Iowa State College Press, Ames. 53U pp.
Soil Survey Staff, 1951. Soil survey manual. U, S. Dept, Agric, Hand book No, 18. 503 pp.
Stebler, A, M. 1939, An ecological study of the mammals of the badlands and the Black Hills of South Dakota and Wyoming, Ecology 20: 382- 393.
Stewart, G., W. P, Cottam, and S. S. Hutchings, 19U0, Influence of unre stricted grazing on northern salt desert plant associations in western Utah, Jour. Agr, Res, 60: 289-316.
Stone, M. H, 19Wi. Soil reaction in relation to the distribution of native plant species. Ecology 25: 379-386,
Thomthwaite, C. W, 19Ul. Climate and settlement in the Great Plains, U. S, Dept, Agric. Yearbook. Climate and Man, pp. 177-187,
U. S, Salinity Laboratory Staff. 195U, Diagnosis and improvement of saline and alkali soils. U. S, Dept, Agric, Handbook No, 60 160 pp,
U. S. Weather Bureau, 1952, Climatic summary of the United States - supplement for 1931 through 1952, Montana, U. S, Dept, of Commerce,
Warren, W, C, 1959. Reconnaissance geology of the Bimey-Broadus coal field. Rosebud and Powder River counties Montana, U. S, Geol, Surv, Bull, 1072-J, pp, 561-585, -12S-
Weaver, J, E, 19$L. North American Prairie. Johnson Publ. Co. Lincoln. 3li8 p p .
• 1961 . The living network in prairie soils, Bot. Gaz. 123: I6 -
1963 . The wonderful prairie sod. Jour. Range Mgmt. I6 : 165-171.
and F. E, Clements. 1938. Plant ecology. McGraw Hill Book Co., Inc. New York. 60 I pp.
Webb, L. J. 19614.* An historical interpretation of the grass balds of the Bunya Mountains, South Queensland, Ecology 159-162.
White, E. M. I 96 I. A possible relationship of little bluestem distribu tio n to s o i l s . Jo u r. Range Mgmt. II4; 2U3-2147.
Whitman, W. and H, C. Hanson. 1939. Vegetation on scoria and clay buttes in western North Dakota. Ecology 20: 1455-W 7 .
Wright, J, G. and E, A. Wright. 191:8. Grassland types of south central Montana, Ecology 29: 1:99-^60. APPENDIX « 1 2 7 -
Appendix I* List of the plant species found in the badlands of south eastern Montana,
Grasses and Grasslike Plants
Agropyron dasystachum (Hook.) Scribn. A. smithii Rydb, A. spicatum (Pursh) Scribn. and Smith A. subsecundum (Link) Hitchc. A. trachycaulum (link) Malta, Andropogon gerardi Vitman. A. scoparius Michx. Aristida longiseta Steud. Bouteloua curtipendula (Michx.) Torr. B. gracilis (H.B.K.) Lag, ex Steud. Bromus tectorum L. Calamagrostis montanensis Scribn, Calamovilfa longifolia (Hook.) Scribn, Carex eleocharis Bailey. C. filifolia Nutt. C, pensylvanica Lamarck, D anthonia u n is p ic a ta (T hurb.) Munro ex Macoun. Distichlis stricta (Torr.) Rydb, Elymus cinereus Scribn, Festuca idahoensis Elmer, Koeleria cristata (L.) Pers, Muhlenburgia cuspidata (Torr.) Rydb. Oryzopsis hymenoides (Roem. and Schult.) Ricker. 0, micrantha (Trin. and Rupr.) Thurb, Poa secunda Presl. Sitanion hystrix (Nutt.) J. G, Smith Sporobolus airoides (Torr.) Torr. S. cryptandrus (Torr.) A. Gray. Stip a coma ta Trin. Rupr, S, viridula Trin.
Forbs
Achillea millefolium L, Allium textile Nels. and Macbr, Ambrosia artem isifolia L, Antennaria parvifolia Nutt, Artemisia dracunculus L, A. ludoviciana Nutt, A ste r spp. Astragalus bisulcatus (Hook.) Gray, A, drummondii Dougl. A, striatus Nutt, Atriplex argentea Nutt, = 1 2 8 —
Appendix I. List of the plant species found in the badlands of south- eastern Montana - Continued.
Forbs - Continued
Balsamorrhiza sagittata (Pursh.) Nutt* Besseya c in e r ia (R a f,) Penn* Cerastium arvense L* Chrysopsis villosa (Pursh*) Nutt* Cirsium undulatum (N utt.) Apreng. Comandra umbellata Nutt* Gryptanthe bradburiana Pays on. Echinacea pallida Nutt* Erigeron pumilus Nutt. Gaillardia aristata Pursh, Gaura coccinea Pursh, Geranium viscossissimum Fisch, and Mey, Geum triflorum Pursh, Grindelia squarrosa (Pursh.) Dunal. Hedeoma drummondii Benth, Helianthus annuus L. Lappula redowskii (Hornem,) Greene, Linum lew isii Pursh* Lupinus argenteus Pursh, Lygodesmia juncea (Pursh.) D, Don. Mentzelia albicaulis Dougl. Opuntia fragilis (Nutt.) Haw. 0. polycantha Haw. Osytropis lambertii Pursh* Fenstemon eriantherus Pursh, P* nitidus Dougl. Phacelia hastata Dougl. P* linearis (Pursh.) Holz, Phlox alyssifolia Greene P. caespitosa Nutt* Plantago purshii R and S. Polygala alba Nutt, Polygonum convolvulus L. P* douglasii Greene Psoralea argophylla Pursh. P* esculenta Pursh. Salsola kali L. Senecio canus Hook. Solidago missouriensis Nutt. Sphaeralcea coccinea (Pursh.) Rydb. Taraxicum officinale Weber. Verbena bracteata L. and R. Vicia americana Muhi. V iola spp. -129-
Appendix I, List of the plant species found in the badlands of south eastern Montana - Continued*
Shrubs and Trees
Artemisia cana Nutt, A, frigida VTilld. A. tridentata Nutt. Atriplex confertifolia (Torr*) S, Wats. Chrysothamnus nauseosus var* graveolens Hall, Eriogonum multiceps Nees. Eurotia lanata (Pursh.) Moq, Gutierrezia sarothrae (Pursh,) B. and R. Juniperus horizontalis Moench. J, scopulorum Sarg, Pinus ponderosa Laws. Rhus trilobata Nutt. Ribes cereum Dougl. Rosa arkansana Porter, Sarcobatus vermiculatus (Hook.) Torr, Suaeda fruiticosa (L.) Forsk, Symphoricarpos albus (L.) Blake. S, occidentalis Hook, Tetradymia spinosa H&A. Yucca glauca Nutt, Appendix II. Summary of the number of feet of line intercept and soil samples collected by location. ( * Indicates locations at which soil samples were collected.)
Community-type Sarco A trip le x A rtem .- A rtem .- Rhus- J u n ip .- J u n ip .- Pinus T o ta l L ocation b atu s A rtem is. A tr ip .- Agropy. Agropy, Agropy. Oryzop, Ju n ip e r I n te r Agropy. cep t Lee Cr, 150 * - 150 * - - 150 * - - 450
E. Fk, Hg. Wo, Cr.(^) - 1 5 0 ^ 150 * 150 150 *■ 150 * 300 * - 1050
Poker Jim Cr. - ---- 125 - 255 380
O 'D ell Cr. 350 * - * ------350
Bear Cr. ------300 * - 300
Horse Cr. - - 200 200 - - - - 400 y Indian-Taylor Cr. - _ * - - _ * - - _ -Jf - I
Cow Or. ------175 175
la y lo r Cr, - 275 800 * - 1050 * 250 - 500 * 2875
Dry Gulch - 150 * 300 - - 600 * -- 1050
F ir s t Cr. - 150 _ * 150 * - - -- 300
Stag Rock Cr. - * - * 100 335 - _ * - - 435
Lyon Cr. ------300 300
Goodspeed Butte - _ * ------
Fifteen Mile Cr. - 300 _ * - * -- - _ * 300 Appendix II. Summary of the number of feet of line intercept and soil samples collected by location. ( * indicates locations at which soil samples were collected.) - Continued,
Community-type S arco A trip le x A rtem .- Artem. - Rhus- J u n ip .- J u n ip .- Pinus T o ta l L ocation b a tu s A rtem is, A tr ip ,- Agropy, ‘Agropy. Agropy, Oryzop, Ju n ip e r I n te r Agropy, cept Pen M ile Cr. 50 - 150 * 150 * _ * - 70 * 420
Coleman Draw 150 250 - -- 125 - - 525
Spring Cr. 150 150 * ------300
Plum Cr. ------* - --
Bloom Cr. _ * _ * _ * 300 * - * - - - 300
Fk, Bloom Cr. --- - 300 * - - - 300 HI S* Fire Cr. 400 * --- 150 * - 150 * - 700
Powder River _ * - - * - _ * -- - -
Total Intercept 1250 1450 ITOO 1285 1800 1400 750 1300 10,910-
Total Soil Samples 6 9 T 5 8 6 3 6
( ) East Fork of Hanging Woman Creek Divide between Indian and Taylor Creeks Unnamed d rain ag e im m ediately south o f F ire Creek -1 3 2 -
Appendix III. Summary of the frequency and abundance data for the Sarcobatus community-type.
(1 ) (2) S p ecies Frequency Abundanc
Grasses and Grasslike Plants; (3) Agropyron dasystachyum A. s m ith ii 20.0 5.2 A. spicatum 1.7 5.1 Bouteloua gracilis 6 .0 23.3 Bromus tectorum 2 .0 0.3 Distichlis stricta 20.7 8.8 Oryzopsis hymenoides 2 .0 1.8 F orbs: A ste r sp p . - o.k Comandra umbellata 0 .7 0.1 Gryptanthe bradburiana - 0.1 Gaura coccinea 0.7 0.1 Grindelia squarrosa 0 .3 0 .1 Lappula redowskii 0.7 0 .1 Opuntia fragilis 0 .7 0,6 0. polycan tha 1.0 l.U Psoralea argophylla 0.7 0 .1 Salsola kali 1.7 0.5 Sphaeralcea coccinea 1 .3 0.1: Vicia americana 0 .7 0.1 S hrubs: Artemisia tridentata 10.0 236.9 Atriplex confertifolia 11.3 89.6 Chrys othamnus graveolens — 2.8 Eriogonum multiceps 7.0 18.7 Gutierrezia sarothrae It.O l l . l Sarcobatus vermiculatus 1*8.7 993.3 Suaeda fruiticosa 15.3 137.1
Grass total li9.0 Forb t o t a l 3.9 Shrub total 11:89.8
Grand total 1512.7
(1) Frequency expressed as a percent of the total $-foot segments observed; see Appendices IV, V, VI, VII, VIII, IX, and X. (2) Abundance expressed in hundredths of a foot per 100 feet of line intercept; see AppendicesIV, V, VI, VII, VIII, IX, and X. (3) - indicates that frequency information was not collected for that species; see AppendicesIV, V, VI, VII, VIII, IX, and X. -133-
Appendix IV. Summary of the frequency and abundance data for the Atriplex-Artemisia community-type.
S p ecies Frequency Abundanc
Grasses and Grasslike Plants: Agropyron spicatum 11.3 10.6 Oryzopsis hymenoides ii.3 ^.6 F orbs: Atriplex argentea 0.7 Ooh Chrysopsis villosa - 0.2 Comandra umbellata O.li Gaura coccinea 0 .7 0.1 Phlox caespitosa - 0.5 Salsola kali - 0.1 Sphaeralcea coccinea 2 .0 0.3 Vicia americana 0 .7 0.1 Shrubs : Artemisia tridentata 12.7 322.2 Atriplex confertifolia 17.7 820.8 Chrjrs othamnus grave olens 1.3 W .9 Eriogonum multiceps 1^.0 80.6 Gutierrezia sarothrae 6 .3 26.9 Rhus trilobata - 2 .5 Sarcobatus vermiculatus 2 .0 12.li Yucca glauca 0.7 1.9
Grass total 16.2 Forb t o t a l 2 .1 Shrub total 1313.2
Grand total 1331.5 -13i+-
Appendix V. Summary of the frequency and abundance data for the Artemisia-Atriplex-Agropyron community-type.
Species Frequency Abundance
Grasses and Grasslike Plants: Agropyron sm ithii 9.h 2 .6 A• spicatum lh l.8 Aristida londiseta Oo5 1 .3 Bouteloua curtipendual 1.7 1.0 B, gracilis - 0.2 Distichlis stricta o .g 0.1 Muhlenburgia cuspidata 1.1 0.2 Oryzopsis hymenoides Uo9 12.3 Sporobolus cryptandrus 1 .1 0.5 Stipa comata - 0 .3 F o rb s; Gryptanthe bradburiana - 0.2 Gaura coccinea 1 .1 0.1 Lappula redowskii 0.5 0 .1 Phlox caespitosa 0 .5 0 .1 Polygala alba 0 .5 0.1 Sphaeralcea coccinea 5 .0 0 .7 Vicia americana 1.1 0.2 Shrubs : Artemisia tridentata 35.0 822.8 Atriplex confertifolia 22.2 528.2 Chrys othamnus graveolens - l.U Eriogonum multiceps - 0.9 Eurotia lanata 0.5 8.ii Gutierrezia sarothrae 12.8 11.1 Rhus trilobata 1.1 6.7 Sarcobatus vermiculatus 3.3 25.9 Yucca glauca 0.5 6.9
Grass total 160.3 Forb t o t a l 2 .6 Shrub total 1112.3
Grand total 1575.2 -135-
Appendix VI. Summary of the frequency and abundance data for the Artem isia-Agropyron community-type.
Species Frequency Abundance
Grasses and Grasslike Plants; Agropyron riparium 0.8 A. s m ith ii 3.8 1.2 A. spicatum 7U-6 219.2 Aristida longiseta 1.7 2.5 Bouteloua curtipendula 11.3 22.8 B. gracilis 2.9 19.2 Bromus tectorum 3.8 0 .5 Carex filifolia — 0 .1 Danthonia unispicata — 0.7 Muhlenburgia cuspidata <-> o.li Oryzopsis hymenoides 5 .0 U.9 Stipa comata 0.8 2.9 S. viridula - k .o F o rb s; A ste r spp. 0.8 0.1 Artemisia dracunculus 0.8 0,1 Atriplex argentea 0.8 0 .1 Cerastium arvense 0.3 Comandra umbellata 1.7 0.2 Hedeoma drummondii 2.5 0 .3 Helianthus annuus 0.8 0.1 Lappula redowskii 1.7 0.2 Sphaeralcea coccinea 6.3 1.2 Vicia americana 1.7 0.2 Shrubs ; Artemisia frigida 0.8 0 .1 A. tridentata 35.0 636.5 Atriplex confertifolia 5.0 27.6 Eriogonum multiceps ii.2 0.7 Gutierrezia sarothrae 9 .6 18 .U Yucca glauca 2 .1 23.8
Grass total 279.2 Forb total 2.8 Shrub total 707.3
Grand total 989.3 -136
Appendix V II. Svimmary of the frequency and abundance data for the Rhus. Agropyron community-type.
Species Frequency Abundance
Grasses and Grasslike Plants; Agropyron sm ithii 5 .0 1,2 A. spicatum U .2 126.8 A. subsecundum - 0,6 Andropogon scoparius 2,2 5.5 Aristida londiseta 0 ,3 0 .3 Bouteloua curtipendula 9 .7 17.9 Bromus tectorum 7.2 1.7 Muhlenburgia cuspidata l.ii U .l Oryzopsis hymenoides 0,6 0.8 Sporobolus cryptandrus 0,6 0.2 Stipa comata 0.6 1.0 Forbs: Ambrosia artemisifolia 1.7 o.U Artemisia dracunculus 3.9 1.8 A ster sp p . l.h 0.3 Cerastium arvense - 0,1 Cirsium undulatum 0,8 0.7 Gryptanthe bradburiana 3.9 2.1 Echinacea pallida 0,6 0.1 Gaillardia aristata - 0.1 Gaura coccinea 8.1 1.3 Grindelia squarrosa 0,6 0,1 Hedeoma drummondii 0,6 0.1 Lappula redowskii 1.1 0.1 Mentzelia albicaulis 2,2 0.3 Oxytropis lambertii - 0.2 Fenstemon eriantherus 0.6 0.1 P. n itid u s 0,6 0.1 Phacelia hastata 1.7 0,3 P. linearis 1.7 0 .3 Polygonum convolvulus 0,6 0.1 P. douglasii — 0,1 Psoralea esculenta 1.1 0.1 Salsola kali 0.6 0.1 Sphaeralcea coccinea 9.U 2.0 Verbina bractiata 2,7 0.5 Vicia americana 2.2 o.L -137-
Appendix VII. Summary of the frequency and abundance data for the Rhus. Agropyron community*-type - Continued,
Species Frequency Abundance
S hrubs; Artemisia frigidia 0.3 1.1 Eriogonum multiceps 11.1 lU .^ Gutierrezia sarothrae 1.9 0.8 Rhus trilobata 827.8 Rosa arkansana 0.6 0.8 Ribes cereum 1.1 11.7 Yucca glauca 0.6 38.3
T re e s; Juniperus scopulorum - 102.7 Pinus ponderosa - lb2.5
Grass total I 60 .I Forb total 11.8 Shrub total 89$ .0 Tree total 2W.2
Grand total 1312,1 -138-
Appendix V III. Summary of the frequency and abundance data for the Juniperus-Agropyron community-type.
Species Frequency Abundance
Grasses and Grasslike Plants; Agropyron smithii 7.8 2.2 A. spicatum 53.9 70,3 Andropogon scoparius 3.9 6.9 Aristida longiseta - 0.8 Bouteloua curtipendula 20.6 11.8 B. gracilis 0.6 0.1 Calamagrostis montanensis 0.6 0 .1 Carex eleocharis 2.2 0.9 C. filifolia - 0.3 Distichlis stricta 0.6 0 .1 Koeleria cristata 2,2 1.9 Muhlenburgia cuspidata 2.2 1.7 Oryzopsis hymenoides 2.2 1.8 Stipa comata - 0.1 S. viridula - O.U F o rb s: Achillea millefolium 8,3 2.5 Antennaria parvifolia 0.6 2,6 Astragalus drummondii 0.6 O.U Artemisia ludoviciana 1.1 0,1 Besseya cineria 0.6 0 .1 Cerastium arvense 7.2 6.8 Erigeron pumilus 0,6 0 .1 Gaura coccinea 1.1 0.2 Geranium viscossissimum 0.6 0 .1 Geum triflorum 0.6 O.U Hedeoma drummondii 1 .1 0,2 Linum lewisii 2,8 O.ii Oxytropis lambertii 2,2 0.2 Phlox caespitosa 1.1 0,1 Polygala alba 2.8 O.U Psoralea argophylla 0,6 0.1 Solidago missouriensis 2.8 1,6 Vicia americana 0,6 0 ,1 Viola spp. 2,2 0,3 -139-
Appendix VIIT. Summary of the frequency and abundance data for the Junip erus-Agropyr on community-type - Continued,
Species Frequency Abundance
Shrubs ; Artemisia frigida 0.6 7.9 A. tridentata 0.6 28.9 Atriplex confertifolia 0.6 7.U Chrys o thamnu s grave olens 0.6 6.8 Gutierrezia sarothrae 8.9 13.1 Rhus trilobata U.U 63.8 Ribes cereum - 22,2 Symphoricarpos albus 0,6 2,2 Yucca glauca - 12,8 T rees: Juniperus scopulorum 66,6 itOl6,3 Pinus ponderosa 0,6 37#0
Grass total 9 9 .U Forb total 16,7 Shrub total 165,1 Tree total Uo53.3
Grand total 1:336,7 —lliO—
Appendix IX, Summary of the frequency and abundance data for the Juniperus-O ryz ops is community-type.
Species Frequency Abundance
Grasses and Grass like Plants; Agropyron smithii 7.6 1.7 A, spicatum Sl.l 5U.0 A, trachycaulum 1.1 0.2 Aristida longiseta 0,6 0 ,3 Bouteloua curtipendula 9,U 7,3 Carex filifolia 6,7 8,6 C, pensylvanica 2,1 Koeleria cristata 1.7 0,8 Oryzopsis hymenoides 1.1 2,7 0 , micrantha 22,8 32,3 F o rb s; Achillea millefolium 9,1; 2,6 Allium textile 0,6 0 ,1 Antennaria parvifolia 2,2 2,1 Artemisia ludoviciana 0,6 0,3 Astragalus bisulcatus 0,6 0,1 Besseya cineria 0,6 0,1 C erastium arvense lU.U 1;.8 Geum triflorum 1,7 0,8 Linum lewisii 1,1 0,2 Oxytropis lambertii 1.1 0,3 Phlox caespitosa 2,2 1,0 Polygala alba 1.1 0,2 Psoralea argophylla 1,1 0,2 Senecio canus 0,6 0 ,1 Solidago missouriensis 9,9 2,2 Sphaeralcea coccinea 0,6 0 ,1 Vicia americana 0,6 0,1 Viola spp, 2,8 0,6 S hrubs; Gutierrezia sarothrae 6,1 21,5 Rhus trilobata 2,8 22,2 Symphoricarpos albus 3,9 11,1 T rees; Juniperus scopulorum Si;,!; 5557,8 Pinus ponderosa 1.1 66,6
Grass total 110.0 Forb total l5 ,6 Shrub total 5U,9 Tree total 5621;,!;
Grand total 5805.2 Appendix X. Summary of the frequency and abundance data for the Finns- Juniperus community-type.
Species Frequency Abundance
Grasses and Grasslike Plants: Agropyron smith!! 3.3 l.U A. spicatum U6.8 91.9 Andropogon scoparius 16.2 5U.5 Aristida longiseta 7.1 Bouteloua curtipendula 23.8 45.2 B. gracilis u.u 19.0 Galamovilfa longifolia 1 .1 0 .4 Carex eleocharis 1.1 0 .4 C. filifoU a 13.8 13.9 Koeleria cristata 3.3 2.9 Huhlenburgia cuspidata 1 .1 4.4 S tip a comat a 1 .1 5 .3 F o rb sî Achillea millefolium 6.9 0.6 Antennaria parvifolia — 1.7 Gerastium arvense 1 .1 1.2 Ghrysopsis villosa L.6 0 .4 Erigeron pumilus — 0 .1 Gaura coccinea 3.3 0.3 Geranium viscossissimum 1.1 0 .1 Lygodesmia juncea 0.3 Cxytropis lambertii U.6 1 .0 Phlox alysslfolia » 0.5 caespitosa — 5.4 Polygala alba 1 .1 0 .1 Psoralea esculenta 1 .1 0 .1 Senecio canus 3.5 0.7 Solidago missouriensis 1 .1 0 .4 Sphaeralcea coccinea 1 .1 0 .4 Taraxicum officinale 1 .1 0 .1 S h ru b s; Artemisia cana _ 34.6 A. f r ig id a 3.5 6.7 Gutierrezia sarothrae 1.1 11.7 Rosa arkansana 2.7 Rhus trilobata h.h 6o.8 T re e s: Juniperus scopulorum H i.5 593.5 Pinus ponderosa 58.9 2315.1
Grass total 246.4 Forb total 13.1 Shrub total 116.5 Tree total 2908.6
Grand total 3302.6 - I l 2 -
Appendix XI, Soil profile descriptions for each community «type.
Sarcobatus Community (1) C ru st 0 to 2 inches, pale brown (lOTR 6/3, dry) to yellowish brown (lOYR $/U, m oist) weak blocky c la y loam; non-calcareous to strongly calcareous* 0 to U inches thick.
( 2) Upper 2 to 9 inches, gray (lOYR 5>/l, dry) to grayish brown (lOYR 5/ 2, moist) weak blocky clay loam; non-calcareous to strongly calcareous. U to 12 inches thick.
( 2) Lower 9 inches +, light gray (lOYR 6/1, dry) weak angular blocky fine sandy loam or silty clay loam; non-calcareous. 12 inches th ic k
Atriplex-Artemisia Community
The soil horizons of this community represent interbedded shales of clay and s ilt as the upper and lower horizon respectively.
Upper 0 to 12 inches, light gray (7.5 YR 7/1, dry) to gray (7.5 YR 6 / 1, moist) granular silty clay; weakly calcareous. 3 inches to several feet thick.
Lower 12 to 2h inches, pale yellow (2.5Y 7/k, dry) to light yellow ish brown (2.5Y 6 /U, moist) granular silty clay loam; weakly calcareous, 3 inches to several feet thick.
(1) Crust was observed in about one-half of the Sarcobatus communities sampled. It is present in areas with high salt concentrations.
(2) Because normal horizons of developed soils are lacking in badland communities, the terms "upper" and "lower" horizons are used to prevent confusion with the standard horizon designation used in soil survey practice (Soil Survey Staff 1951). Appendix XI> Soil profile descriptions for each community-type. _ Continued
Artemisia-Atriplex-Agropyron Community
These soils are characterized as shallow to moderately shallow colluvium deposits overlying interbedded geological materials *
Upper 0 to 10 inches, dark grayish brown (lOYR I4./2, dry) to dark brown (lOYR 3/3, moist) weak sub angular blocky or fine platy clay loam; weakly calcareous, 3 to 12 inches thick.
Lower 10 in c h e s +, l i g h t gray (lOYR 6 /I, dry) to pale brown (lOYR 6/3, moist) weak subangular blocky silty clay loam; calcar eous, 3 inches to 5 inches thick,
Artemisia-Agropyron Community
These soils are similar to those of the Artemi si a-Atriplex- Agropyron community, except for a deeper colluvium deposit,
(1 ) Upper 0 to 7 inches, light yellowish brown (10ÏR 6/k, dry) to yellowish brown (lOYR moist) granular or platy silt loam; weakly calcareous, 0 to 10 inches thick.
Lower ? to 2h inches, brown (lOYR 5/3, dry) to yellowish brown (lOYR 5/6, moist) sub angular blocky silt loam; weakly cal c areo u s, 15 to 2l(. inches thick,
Rhus-Agropyron Community
These soils are primarily composed of porcellanite chips and large coarse fragments.
Upper 0 to lU inches, reddish brown (5YR 5/L, dry, 5lR hfk, m oist) weak fine subangular blocky silt loam; strongly calcareous, lii inches + thick,
( 2 ) Lower II4. inches +, reddish brown (5ïH 5/It, dry) subangular blocky to granular silt loam; strongly calcareous, 0 inches thick, ( 1) This upper horizon is not present at every sampling location, and may represent an advanced stage of soil development not entirely indica tive of badland soils, ( 2) Lower horizon encountered only at Taylor Creek location, and is not characteristic of these soils. - 1I4U—
Appendix XI, Soil profile descriptions for each comjnunity-type - Continued»
Juniperas-Agropyron Community
These soils are mostly present in secondary drainage channels and on east, south-east, south-west, and west exposures.
Upper 0 to 7 inches, brown (lOTR ^/3, dry) to dark yellowish brown (lOTR h/hi moist) fine granular silt loam; weakly calcareous, 3 to 1)4 inches thick.
Lower 7 to 16 inches, yellowish brown (lOTR 5A, moist) fine granular silty clay loam; weakly calcareous, 5 to 20 inches thick.
Juniperus-Oryzopsis Community
These soils are characteristically found on north, north-west, or north-east exposures.
Litter 1 to 0 inch, partially decomposed leaves of juniper.
Upper 0 to 7 inches, dark yellowish brown (10ÏR dry) to dark brown (lOYR U/3, moist) fine granular silty clay loam; weakly calcareous, I4 to 12 inches thick.
Lower 7 to 18 inches thick, brown (lOYR 5/3, dry) to dark yellowish brown (lOYR h/k, moist) fine blocky clay loam; weakly calcar eous, 5 to 12 inches thick.
Pinus-Juniperus Community
These soils are characterized as occurring in colluvium deposits at the base of badland slopes, typically composed of large sandstone coarse fragments.
Upper 0 to 11 inches, dark brown (7.5% h/hf dry, 7.5% U/l, moist) angular blocky s ilt loam; weakly calcareous, k to 18 inches th ic k .
Lower 11 to 2k inches thick, light yellowish brown (lOYR 6 /I4, dry) to yellowish brown (10% 5/^^ moist) massive fine sandy loam; strongly calcareous, 10 to 2k inches thick. Community-types G eological Depth of Res idual Exposure Percent Slope - M aterial S o il or Slope P osition M aterial Transported Sarcoloatus Interbedded clay Upper 0-9" Residual 8W-88E 0-80 Middle I and s i l t sh ales, and and a and stream te r Lower 9" Alluvium (8) (36.4) Lower H races .
Atriplex- Interbedded clay Upper 0-12” Residual W-SSE 65-100 Middle- Artemisia and s i l t shales Lower 12” (8SW) (75.7 Lower
Artemisia- Talus of sand Upper 0-10” Colluvium SW-SE 54-69 Middle A triplex- stone, si It stone (60.7) Agropyron over interbedded Lower 10-15" (s) J39 fl) C+- hi . y shales ; shallow. n> n>
I Artemisia- Talus of sand Upper 0-T" Colluvium SW-SE 35-36 Lower- f?i e VJ1 Middle I Agropyron stone, siltstone (47.4) 3 I" 3 over interbedded Lower 7-24” (s) shales; deep. '5 H* (0
Eîhus- Red colored Upper 0-24” Residual W-SE 40-86 Upper Agropyron porcellanite bed Usually no or (64.6) m aterial lower Colluvium (s) II grg Juniperus- Fine-text ured SW-RE Middle- H»CQ O<+ Upper 0-7" Residual 30-59 w n> Agropyron talus over or (sw) (43.9) Lower 4 H‘ interbedded Lower 7-16" Colluvium *8 8- shales HJ H* rt> o 03 03 Entire- Juniperus- Fine-textured Upper 0-7" Residual mw-ïïE 30-54 1 % Qryzopsis soil over inter ( 3 8 . 5 ) Middle bedded shales Lower 7-18" (m e ) g s wg g- Pinus- Knolls of sand Upper 0-11" Residual NW-SE 0-55 Lower- Juniperus stone, siItstone Lower 11-24” or (ssw) (22.0) Middle fragments Colluvium