An ecological study of a relict of grassland and an adjacent grazed pasture in Beaverhead Valley,
Montana
by Michael P Britton
A THESIS Submitted to the Graduate Faculty i n partial fulfillment of the requirements for the degree
of Master of Science in Plant Ecology at Montana State College
Montana State University
© Copyright by Michael P Britton (1955)
Abstract:
A detailed ecological study was made of a relict area which has been protected for 39 years and an
adjacent grazed pasture in Beaverhead Valley in southwestern Montana during the summers of 1953
and 1954. The study area is located at an elevation of 5100 to 5200 feet. The soils were classified as
sierozems, and four separate types occurred. The average annual precipitation at Dillon, Montana is
15.97 inches, 67 percent being received during the period April 1 to September 30. The average
temperature for this period is - 55.6° F. Vegetation density was determined by the point-transect
method. List quadrats were used to measure frequency and abundance of forbs and shrubs. Sampling
areas were located on each of the four soil types in the relict area and the grazed pasture. Soil profile
descriptions were made for each soil type. Differences in community composition on each soil type in
the relict area and the grazed pasture are presented in tabular form and are discussed. The
Agropyron-Poa type found on the most mature soils was assumed to be the climatic climax of the
region. Two edaphic climaxes are discussed. Agropyron spicatum was the dominant plant on the relict
area, whereas the grazing disclimax was dominated by Stipa comata. . 4 -3
S -S "
ANA RESOURCES .
COLLECTION
AN E C O L O G I C A L S T U D Y OF A R E L I C T OF G R A S S L A N D
AN A D J A C E ' N T G R A Z E D P A S T U R E I N B E A V E R H E A D V A L L E Y ,
BY
MICHAEL P e BRITTON
A THESIS
S u b m itte d to the
Graduate
Faculty
in
partial fulfillm ent
for th e
Master
of th e r e q u i r e m e n t s
degree
of S c i e n c e
of
in P la n t Ecology
at
M ontana State
College
Approved:
Head,
Major
Chairman,
Dean,
Department
Examining
Graduate
Com mittee
Division
Bozeman, Montana
April, 1955
MONTAINA STATE COLLEGE LlBhARN
BOZEMAN
AND
MONTANA
—
TABLE
A B S T R A C T ........................................................
INTRODUCTION
.....................................
OF
2
—
CONTENTS
Page
3
4
A C K N O W L E D G E M E N T S .........................
6
D E S C R I P T I O N OF S T U D Y
6
AREA .
C L I M A T E ........................................................
, 9
.........................
9
D I S C U S S I O N AND CO N CL U SI O N S
10
S U M M A R Y ........................................................
22
LITERATURE
22
M E T H O D S OF S T U D Y
CITED
3
ABSTRACT
A d e t a i l e d e c o l o g i c a l s t u d y was m a d e of a r e l i c t a r e a w h i c h has b e e n
p r o t e c t e d f o r 39 y e a r s a n d a n a d j a c e n t g r a z e d p a s t u r e i n B e a v e r h e a d V a l l e y
i n s o u t h w e s t e r n M o n t a n a d u r i n g t h e s u m m e r s of 1 95 3 a n d 1 9 5 4 .
The study
a r e a is l o c a t e d a t an e l e v a t i o n of 5 1 0 0 to 5 2 00 f e e t .
The soils were c l a s s i­
f i e d as s i e r o z e m s , a n d f o u r s e p a r a t e t y p e s o c c u r r e d .
The average annual
p r e c i p i t a t i o n a t D i l l o n , M o n t a n a is 1 5 . 9 7 i n c h e s , 67 p e r c e n t b e i n g r e c e i v e d
du rin g the p e r io d April I to S e p te m b e r 30.
T h e a v e r a g e t e m p e r a t u r e for
t h i s p e r i o d i s -5 5 . 6° F .
V e g e t a t i o n d e n s i t y was d e t e r m i n e d by th e p o i n t transect method.
List q u a d r a ts w ere u se d to m e a s u r e f r e q u e n c y and a b u n ­
d a n c e of forbs a nd sh r u b s.
S a m p l i n g a r e a s w e r e l o c a t e d on e a c h of t h e
four soil ty p e s in th e r e l i c t a r e a and the g raz ed p a s t u r e .
Soil profile d es­
c r i p t i o n s w e r e m a d e for e a c h s o i l t y p e .
D if fe re n c e s in c o m m u n i t y c o m p o ­
s i t i o n on e a c h s o i l t y p e i n t h e r e l i c t a r e a a n d t h e g r a z e d p a s t u r e a r e p r e ­
se n te d in ta b u la r form and are disc u sse d .
T h e A g r o p y r o n - P o a t y p e f o u n d on
th e m o s t m a t u r e soils was a s s u m e d to be th e c l i m a t i c c l i m a x of th e r e g i o n .
Two e d a p h ic c l i m a x e s are d iscu ssed .
A gropyron s p ic a t u m was the d o m in a n t
p l a n t on t h e r e l i c t . a r e a , w h e r e a s t h e g r a z i n g d i s c l i m a x was d o m i n a t e d by
Stip a c o m a t a .
- .4
INTRODUCTION
" Current range vegetation
degrees
of p a s t d i s t u r b a n c e
over such v ast are a s,
not realize
once
k i n d of v e g e t a t i o n . " ^
Since the
of such l o n g s t a n d i n g ,
and terraces
spring- fall ranges
(Weaver
and
communities
of p l a n t s
viscidiflorus
(Fig.
in the
1800s,
vegetation
Clements,
the ap p e aran c e
1 9 38).
types:
of v e g e t a t i o n .
Short grass,
Morris
on m o s t of
Mixed Prairie
g rasslan d are
and Chrysothamnus
of M o n t a n a i n t o t h r e e
mixed
and fo o th ills.
and arid associations
for e a c h
grass,
occupying the
of th e
regions
They in c lu d e d Beaverhead Valley
open
(1946) classified the
Mixed Prairie
were indicated
of the
In te r s p e rs e d in the
d o m i n a t e d by E u r o t i a l a n a t a
Montana.
of s o u t h w e s t e r n M o n t a n a has n o t b e e n s t u d i e d i n t e n s i v e l y .
the western valleys
sem iarid,
o c c u r r i n g on
g rasslan d has b e e n
d o m in a n t grass
M o u n t a i n R e g i o n w h i c h was d e s c r i b e d
bunchgrass type.
com plexes:
m o s t of t h i s
S t i p a c o m a t a is t h e
and gives them
dom inant type
Central
of th e g r a s s l a n d s
different
of B e a v e r h e a d V a l l e y in s o u t h w e s t e r n
R e i t z a n d M o r r i s (1 9 3 9 ) d i v i d e d t h e r a n g e l a n d s
on the
a quite
I).
The v eg e ta tio n
based
occur
t h a t m a n y s t o c k m e n do
did and can ag a in produce
v a l l e y was s e t t l e d in th e l a t e
Association
Grazing d isc lim a x e s
This ap p e ars to be true
u s e d for s p r i n g - f a l l r a n g e .
these
o f t e n t h a n no t a p r o d u c t of v a r y i n g
by m a n 's li v e s t o c k .
and are
their ranges
the lower benches
is m o r e
.,
as b e i n g
forest,
grasslands
Great Plains,
These in turn were
up of f o u r
and the pacific
■s
of M o n t a n a i n t o two
and Palouse
P ra irie in
divided into subhumid,
c o rre sp o n d in g to soil zones.
associations
made
under m oderate
Dom inant species
and heavy
grazing
I Cooper, H. W ., 1953. Amounts of b ig sagebrush in p la n t co m m u n ities near T ensleep, W yoming, as
a ffe c te d by grazing tre a tm e n t. Ecology 34, p . 186»
5
on tw o d i f f e r e n t s o i l t e x t u r e s .
study
of t h e
ten re lic t
The
grasslands
areas
diversity
extreme
Prairie
topographic
variation,
W r i g h t (1 9 4 8 ) m a d e
M ontana.
They
described
into types based upon the
of s o u t h - c e n t r a l
in d e ta il
dominant
grasses.
M o n t a n a was a t t r i b u t e d
with its a s s o c ia te d
t o as a t e n s i o n z o n e l y i n g b e t w e e n
an e c o l o g i c a l
the
clim atic
Palouse
differences,
Prairie
and
to the
and
Mixed
Associations.
author
vations
and grouped these
grasslands
Observations
the
of s o u t h - c e n t r a l
of t h e
was r e f e r r e d
Wright and
made
on r e l i c t
th a t the p r e s e n t
of B e a v e r h e a d
Mixed
areas during
Prairie
1 953
and 1 954 h av e
Association
occupying
V a l l e y is a d i s c l i m a x t h a t has r e s u l t e d
indicated
to
the lower e l e ­
from
overgrazing
6
an o rig in a l Palouse
these
or B u n c h g r a s s P r a i r i e
observations this thesis presents
type
of v e g e t a t i o n .
In s u p p o r t of
t h e r e s u l t s of a d e t a i l e d s t u d y of a
r e li c t area which has been p ro te c te d
from
g r a z i n g for t h e l a s t 39 y e a r s .
ACKNOWLEDGEMENTS
The
directed
au th o r wishes to a c k n o w le d g e
assistance
the study and a i d e d in the p r e p a r a t i o n
a p p r e c i a t i o n is e x t e n d e d to Mr.
vice
the
for a s s i s t a n c e
Soil. C o n s e r v a tio n
A.
A.
J.
C.
W right who
of the m a n u s c r i p t .
A n d e r s o n of th e Soil
in d e s c r ib in g the soil p r o f i l e s .
Service,
of Dr.
Dr.
E.
Sincere
Conservation Ser­
J.
generously contributed literature
Dyksterhuis,
from his p e r ­
sonal files.
D E S C R I P T I O N OF S T U D Y A RE A
The study area lies
level
a n d is l o c a t e d
about three
gently sloping terrace
Creek.
The soils are
or a n d c a l c a r e o u s
at an a l t i t u d e b e t w e e n
5100 and 5200 fe e t above sea
m i l e s sou th of D i l l o n ,
formed between Beaverhead
classified
throughout.
as s i e r o z e m s ,
M o n t a n a on a lo w
River and B l a c k t a i l Deer
b e in g l i g h t g ra y - b ro w n in c o l ­
T h e p a r e n t m a t e r i a l is t e r t i a r y
lake bed sed i­
ment.
The r e lic t
mile
long (Fig.
1915,
a r e a is f e n c e d
2).
on a l l s i d e s a n d is a b o u t 16 f e e t w i d e
A cc o rd in g to the p r e s e n t ow ners,
and p re v io u s to t h a t t i m e
of the pastures presently
on s e v e r a l
grazed since
the
a r e a was fe n c e d in
i t was g r a z e d a n d h a d th e
general appearance
a d j a c e n t to. i t .
occasions when the
and one
Although
the
area has bee n
f e n c e s w e re in n e e d of r e p a i r ,
grazed
it has n o t.b e e n
1940,
Four soil types
are found in the
study area (Table
I).
Three
are lo a m s ;
7
two
of t h e l o o m s
a shallow
soil and rec eiv e s
or p e r i o d s
ing
of r a p i d
a lim e
pasture.
calves
there
were
until
o n e of w h i c h is g r a v e l l y .
additional
snowmelt.
The
moisture
fourth
T h e t h i r d l o a m is
from runoff during heavy rains
soil type
is a d e e p
sandy loam l a c k ­
layer.
An a c c u r a t e
acre
are deep soils,
h i s t o r y of g r a z in g use was n o t a v a i l a b l e
However,
turned into
July I .
approxim ately
during
19 5 3 and 1954 a p p ro x im a te ly
the pasture
The pasture
I 50 c o w s
during the
was u t i l i z e d
during
the
a g a in in the
entire
adjoining
year.
fall
640
150 cows with
first w eek in May
for a four to six w e e k p e r i o d .
ed in th e p a s t u r e p e r i o d i c a l l y
on t h e
and were
kept
of t h e y e a r by
About five horses
According
to the
graz­
owner
TABLE I.
SOIL TYPE HORIZON
DEEP
LOAM
AND DEEP
GRAVELLY
LOAM*
DEPTH BOUNDARY
Al
0-6"
B2
6-15"
Cca
15-25"
C
25-38"
D
38"plus
Al
0-6"
B2
6-11"
SHALLOW
LOAM
C ca
C
DEEP
SANDY
LOAM
COLOR
B2
3-11"
C
11-22"
A lb
22-25"
B2b
25-36"
Cb
36-43"
43"plus
DESCRIPTIONS
TEXTURE
dry: lig h t brownish gray lo am
moist: dark grayish brown
silt lo a m
dry: p ale brown
m oist: brown
STRUCTURE
CONSISTENCE
REACTION
m oderate, th in p la ty
dry: soft
m oist: friable
dry: slig h tly hard
m oist: friable
slight
effervescence
slight
effervescence
dry: soft
m oist: friable
dry: soft
moist: friable
strong
effervescence
slight
effervescence
m o d erate, coarse
prism atic to coarse
subangulcr blacky
lo am
w eak, m edium
dry: very p ale brown
c le a r,
subangular black y
smooth
m oist: brown
dry: lig h t yellow ish brown fine sandy m assive
clea r,
m oist: yellow ish brown
lo am
smooth
unassorted sands and gravels
c le a r,
smooth
c le a r,
smooth
dry: lig h t brownish gray
m oist: dark gray-brow n
dry: p ale brown
m oist: brown
dry: very p ale brown
c lea r,
smooth
moist: brown
2 2 -3 0 "plus; unassorted sands and gravels
0-3"
♦♦sticky w hen w et
PROFILE
11-22"
Al
♦contains 20% gravel
c le a r,
smooth
c le a r,
smooth
SOIL
c lea r,
smooth
clea r,
smooth
abrupt,
smooth
clea r,
smooth
clea r,
smooth
c le a r,
sm ooth
unassorted
dry: lig h t brownish gray
m oist: dark gray-brow n
dry: lig h t brownish gray
m oist: dark gray-brow n
dry: p a le brown
moist: brown
dry: lig h t brownish gray
m oist: dark gray-brow n
dry: lig h t brownish gray
m oist: dark gray-brow n
dry: p a le brown
m oist: brown
sands and gravels
lo a m
silt lo a m
silt lo am
m o d erate, th in p laty dry: soft
moist: friable
dry: slightly hard
m o d erate, coarse
p rism atic to m cder- moist: friable
a te ly coarse
subangular blocky
m oderate, m edium dry: slig h tly hard
subangular blocky
m oist: friable
sandy lo am w eak, fine crum b
dry: soft
moist: friable
silt lo a m m o d erate, coarse
dry: slig h tly hard
m oist: friable
p rism atic
sandy lo am m edium ,
dry: soft
subangular blocky
m oist: friable
silty clay m o d erate, th in p la ty dry: slig h tly hard
lo am
moist: stick y ♦♦
silt lo a m m o d erate, coarse
dry: slightly hard
subangular blocky
m oist: friable
fine sandy massive
dry: soft
lo am
moist: friable
*■
slight
effervescence
slight
effervescence
v io len t
effervescence
strong
effervescence
strong
effervescence
strong
effervescence
strong
effervescence
strong
effervescence
strong
effervescence
9
this rate
of s t o c k i n g
has b ee n p r a c t i c e d
f o r t h e p a s t 4 0 or 50 y e a r s .
CLIMATE
Average
covering
monthly
a period
precipitation
and te m p eratu re
data
o f S3 y e a r s a r e p r e s e n t e d i n T a b l e
TABLE I I .
CLIMATIC
for D i l l o n ,
Montana
II.
D A TA FOR DILLON,
MONTANA
Apr. I
to
S e p .30
1 0 .7 8
5 5 .6
Ann­
ual
Ave.
Nov
Dec
Sep
Oct
Aug
Jul
Jun
Apr
May
Feb
Mcr
Jan
Ave. p p t. ( in .) 0 .8 3 0 .7 2 1 .1 6 1 .6 8 2 .6 9 2 .4 4 1 .3 9 1 .1 8 1 .4 0 0 .9 4 0 .8 0 0 .7 4 1 5 .9 7
Ave. te m p . ( 0Ft ) 2 2 .5 2 7 .0 3 4 .0 4 3 .2 5 0 .6 5 7 .8 65.1 6 3 .0 5 4 .0 4 5 .8 3 4 .5 2 6 .2 4 3 .9
The sierozem
soils
cipitation received
ever,
seasonal
tem peratures
there
months
has
of h e a v i e s t r a i n f a l l .
where the
cool summers.
M a y 22 a n d t h e
12,
giving
thwaite
The
average
an a v e r a g e
clim ate
April
date
The average
date
of th e
for t h e
same
with little
clim ate,
or no w a t e r
of p l a n t s
encountered
at Dillon.
May and June are
during the period
City,
a G reat Plains
Dillon
f r o s t i n t h e s p r i n g is
frost in the
f a l l is S e p t e m b e r
According
to the T h o r n -
D illo n has a m i c r o t h e r m a l ,
surplus.
OF S T U D Y
on t h e
How­
and m onthly
p e r i o d i s 6 2 . 9 ° F. ,
of th e l a s t k i l l i n g
frost free s e a s o n of 112 d a y s .
annual p re­
annual precipitation
30.
tem perature
first k illin g
of c l a s s i f y i n g
average
annual
average
C o m p a r e d to Miles
METHODS
All sp e cie s
total
I and S ep te m b er
tem perature
average
and average
Of t h e
30 is 5 5 . 6 ” F.
average
(1 9 4 8 ) s y s t e m
subhumid
between
th a t the
lower than reported
of p r e c i p i t a t i o n
s h o u ld be c o m p a r a b l e .
April I to S e p te m b e r
station,
study are a in d ic a t e
is c o n s i d e r a b l y
distribution
67 p e r c e n t is r e c e i v e d
the
of t h e
area were
collected
and
dry
10
identified
(Table
III).
The v e g e ta tio n
'
of the
stu d y a r e a an d th e p a s t u r e was s a m p l e d in d e t a i l by
the p o in t- tr a n s e c t m ethod (Clarke
tangular
rats.
frame
et al. ,
1942)
and by lis t
four fee t long and one foot wide
D en sity of the
vegetation
quadrats.
A rec­
was used in m a k i n g l is t q u a d ­
was o b t a i n e d by th e p o i n t - t r q n s e c t m e t h o d .
List q u ad ra ts w ere used to d e t e r m i n e
frequency
and abundance
of h e rb a c e o u s
and shrubby species. .
The p o in t- tr a n s e c t
the
areas
studied.
T h e p o i n t f r a m e was p l a c e d
a 200 foot t r a n s e c t
soils.
loam
m e t h o d was m o d i f i e d to a d a p t i t to t h e s m a l l size of
on t h e
One foot i n te r v a ls
soil.
deep loam ,
of t e n p o i n t s
p o in t was in c o n t a c t* w ith
shrubs w ere sc o re d
the
each.
A " hit"
only when the p la n t ca m e
grass p la n ts.
shrubs,
ground,
Because
the
and sandy loam
w as s c o r e d on g r a s s e s
the p la n t at ground le v e l.
above
c a u s e i t was n o t i c e d t h a t w hen th e b r a n c h e s
above the
gravelly loam,
graz ed and u n g r a z e d v e g e t a t i o n was s a m p l e d
g round l e v e l to a h e i g h t of two in c h es
inches
of two f e e t a l o n g
a l o n g a 1 00 f o o t t r a n s e c t w e r e u s e d on t h e s h a l l o w
On each, s o i l t y p e
by 100 fra m es
deep
at intervals
the
" Hits"
i t was f e l t t h a t a m e a s u r e m e n t
on forbs and
in c o n t a c t w ith the p o in t from
the
ground.
This was done b e ­
o f t h e s h r u b s w e r e t w o or m o r e
a r e a u n d e r n e a t h was f re q u e n tl y
grass p la n ts
only if the
actually
d o m i n a t e d by
dom inated the
of c o m p l e t e
soil under the
crown cov erag e
of t h e
shrubs was n o t s i g n i f i c a n t . •
Soil profile
used,by the
Soil
descriptions were made
Conservation
according
to the m e t h o d p re s e n tly
Service.
D I S C U S S I O N AND C O N C L U S I O N S
Considering the r e lic t area
as a w h o l e ,
the p ercen tag e
of so il s u r f a c e
11
TABLE I I I .
SCIENTIFIC
NAMES OF P LA NT S
GRASSES AND SEDGES:
Agropyron cristatum (L. ) Beany.
Agropyron sm ith ii Rydb.
Agropyron spicatum (p u rsh ,) Scribn. and Sm ith
Bouteloua g racilis (FfflK) Lag.
Bromus te cto ru m L.
C alam agrostis m ontanensis Scribn.
K oeleria c rista ta ( L .) Pers.
Cryzopsis hym enoides (R oem . and S chult. ) R icker
Poa conbyi (Scribn. ) Piper
Poa pratensis L.
Poa secunda Presl.
S itanion hysterix ( N u tt.) J . G . Sm ith
S tipa c o m a ta T rin. and Rupr.
S tipa virid u la T rin,
C arex eleocharis Bailey
FORBS AND SHRUBS:
A ch illea la n u lcsa N utt,
Agcseris g lauca (P ursh,) D. D ietr.
A llium te x tile N els. and M acbr.
A ntenna ria m ic ro p h y lla Rydb,
A rtem isia frigida W illd.
A rtem isia lu d o v ician a N utt.
A rtem isia trid e n ta ta N utt.
Aster scopulcrum Gray
A stragalus inflexus Dougl,
Astragalus m iser Dougl. vcr. decum bens (N u tt.) Cronq.
A triplex~nuttallli A. Watts
Besseya c in e ria ( R a f .) Penn,
Chrysotham nus nausecsus ( P a ll.) Britt.
Chrysothamnus viscidiflorus (Hook, ) N utt.
Cynogiossum o ffic in a le ET
Erigeron com positus Pursh.
Erigeron p u m ilis N utt.
Eriogonum ov alifo liu m N utt.
Eriogonum m icrothecum N utt.
Erysimum ch eiranthoides L.
Eurotia Ia n a ta (P ursh.) Moq.
G aura co c c in e a Pursh.
G rindelia squarrosa (P ursh.) Dunal
H aplopappus acaulis ( N u tt.) Gray
L appula redow skii (H c rn e m .) G reene
L ithosperm um i ncisum Lehon.
M usineon d iv a ricatu m (P u rsh .) R af.
O puntia p o ly acan th a Haw.
Phlox hoodii R ich.
Phlox lo n g ifo lia Nutt.
P o ten tilla pennsylvanica L.
R ibes setosum Lindl.
S p h aeralcea c o c c in e a (P ursh.) Rydb.
T araxacum officin ale Weber
Tragopogon dubius Scop.
V ic ia sparsifolia N utt.
USED.
“ 1 2 “
o c c u p i e d by a ll s p e c ie s
10.6
p e r c e n t of this
averaged 15.3
cover,
shrubs
A g r o p y r o n spi c a turn was t h e
the to tal
and 7.2
density.
grasses.
byi in the
a n d f orbs 1 . 6
field;
therefore,
eleocharis
the basal
m ontanensis,
were
species
Stipa c o m a ta ,
den­
s e c u n d a a n d P o a c a,n -
Oryzopsis h y m e n o i d e s ,
and
m a k i n g up 1 4 . 4 p e r c e n t of
area.
m a k i n g up 4 6 . 8
and shrubs.
E u r o t ia l a n a t a was the
p e r c e n t of th e n o n - grassy c o v e r .
was of n e x t i m p o r t a n c e
forming 14.9
percent
most im portant component,
Chrysothamnus vlscidiflorus ,
of the
Phlox I o n g ifo lia 1 Lappula red o w sk ii,
decumbens,
tallii
p e r c e n t of th e n o n - grassy c o v e r .
formed 25.5
Abundance
V ic i a S p a r s if o lia 1 and th e shrub
d a t a s h o w t h a t 20 s p e c i e s
ly a b u n d a n t to occur in an a v e r a g e
(Table
c o m b i n e d a r e a of f orbs
Sphaeralcea
ragalus miser v a r.
coccinea,
Ast­
A trip l ex n u t -
of f orbs and 6 shrubs w e r e s u f f i c i e n t ­
of tw o p e r c e n t
or m o r e
IV).
Variation
relative
total
a r e r e f e r r e d t o a s P_. s e c u n -
of se c o n d a ry i m p o r t a n c e ,
Of "t he f o r bs a n d s h r u b s ,
rats
most im portant
5 4 .9 p e r c e n t of the
to d i f f e r e n t i a t e betw e en_P »
of t h e s e
p e r c e n t of
forming 14.4 percent
were the
grasses form ed
both
percent.
m a k i n g up 3 3 , 3
and Agropyron s m i th ii,
These three
Calamagrostis
Carex
percent,
dominant grass,
Poa s e c u n d a
No a t t e m p t was m a d e
da.
3.1
G ra s se s ' a n d s e d g e s m a d e up
p e r c e n t of the t o t a l co v e r r e s p e c t i v e l y ,
associated
sity.
percent.
of th e l i s t
quad­
'
in soil te x tu r e
dominance
and profile
depth
caused a significant
as c a n b e s e e n f r o m a n e x a m i n a t i o n
of T a b l e
chan g e in
V and Figure
3.
On t h e
total
deep loam
vegetation,
soil (Fig.
4),
d e c l i n e d to 5 1 .8
A.
spicatum
p e r c e n t on th e
m a d e up 6 6 . 8
deep
p e r c e n t of th e
gravelly loam
( F i g . 5),
v
I3
TABLE I V .
FREQUENCY
AND A B U N D A N C E OF SHRUBS
SPECIES NAME
Phlox lo n g ifo lia
S p h aeralcea c o c c in e a
A triplex n u tta llii
E urotia la n a ta
Chrvsotham nus viscidiflcrus
L appula re'dowskii
A rtem isia M g id a
V ic ia spofsifc lia
O puntia poly acan th a
G aura c o c c in e a
T araxacum officinale
A stragalus m iser
Chrysotham nus nauseosus
H aplopappus acdulis
A ntennaria m icrophylia
A rtem isia lu d o v ician a
Phlox hoodii
Tragopogon dubius
A ch illea ld n u lc sa
Agcseris plane a
Erigeron pum ilis
Eriogonum ovalifolium
Eriogonum m icro th ecu m
G rindelia squarrosa
M usineon d ivaricatum
Erysimum cheiranthoides
A llium te x tile
A rtem isia M d e n ta ta
Aster scopuldrum
Astragalus inflexus
Besseya c in e ria
Cynoglcssum officin ale
Erigeron com pcsitus
Lithosperm um incisum
P o ten tilld pennsyl'vanica
Ribes setosum
*
A verage num ber of plants per 100 square fe e t of a re a .
** Frequency less than 2 %.
*** Less than I p la n t per 200 square fe e t of a re a .
FREQUENCY %
54
38
32
30
30
28
18
10
10
8
8
4
4
4
4
2
2
2
2
2
2
2
2
2
2
2
t**
t
t
t
t
t
t
t
t
t
AND F OR BS .
ABUNDANCE*
7 6 .0
2 1 .0
8 .0
2 5 .5
1 3 .5
5 6 .0
6 .5
1 0 .5
2 .5
2 .0
2 .0
5 .5
1 .5
1 .0
1 .0
4 .0
1 .0
1 .0
0 .5
0 .5
0 .5
0 .5
0 .5
0 .5
0 .5
0 .5
-* * *
-
TABLE V.
GRASSES AND GRASSLIKE
PLANTS
D E N S I T Y OF V E G E T A T I O N IN PERCENT
DEEP LOAM
DEEP GRAVELLY
DEEP SANDY
ENTIRE STUDY
SOIL
LOAM
SHAl.LOW LOAM
LOAM
AREA
PROPROPROPROPROTECTED GRAZED TECTED GRAZED TECTED GRAZED TECTED GRAZED TECTED GRAZED
Agropyron spicatum
Poa canbyi
)
Poa secunda )
Agropyron sm ithii
C alam agrostis m ontanensis
Stipa c o m ata
Oryzopsis hym enoides
C arex eleocharis
.7
————
.2
.5
- —
———
.9
.5
TOTAL GRASS DENSITY
1 3 .7
3 .0
1 .6
1 .3
.4
1 .6
.2
.2
1 1 .7
1 .5
6 .9
1 .8
1 .8
.4
.6
.1
.7
—
1 .5
.1
2 .3
.4
—
1 .3
3 .7
1 .0
.3
.3
1 .4
.6
4 .7
.2
.1
9 .3
4 .6
9 .9
6 .5
.1
1 .2
.7
.1
.2
.3
.1
.7
—
.4
1 .4
.1
— —
.1
———
5 .1
.9
6 .3
2 .4
2 .2
.6
1 .6
.4
.4
.1
2 .8
.3
.1
.4
.2
1 .1
.9
.6
.5
.2
9 .3
6 .3
1 0 .6
5 .2
8 .6
2 .3
2 .2
.7
.5
.2
.2
.1
.1
.1
.5
.5
.1
.1
mmmmmm
1 .0
3 .3
mmmmmmmm
SHRUBS AND FORBS
Eurotia la n a ta
Chrysothamnus viscidiflcrus
Phlox lo n g ifo lia
A triplex n u tta llii
Lappula redow skii
S p haeralcea co ccin ea
Astragalus m iser var. decum bens
V icia sparsifo lia
Chrysothamnus nauseosus
O puntia p o ly acan th a
Phlox hoodii
A rtem isia lrigida
Astragalus inflexus
G aura c o c cin ea
T araxacum officinale
TOTAL SHRUBS AND FORBS
TOTAL DENSITY
—eeeeee
.3
.1
mammm
M ———
.2
.4
.3
mmammm
— ———
■ ■■■
“ ■■■
.1
.1
.3
.1
.1
.1
.3
■■■»
.1
■■ ■
.3
.1
.1
mmrnmmm
——■
mm^mm
mmmmmm
.3
.2
.1
_w
.3
.1
.1
.2
.9
.1
mmrnmmm
mmrnmmm
mmmmrn
.3
.2
i ——
■ •i —
mmmmmm
mm■ ##
___
mmmmmmmm
mmmmmmm
.1
.1
.mmmmmmm
.2
. t
.1 5
.1
■ ■w
mmmmmmm
——I
____
mmrnmmm
mmrnmmm
m m m m
m m m m
mmmmmm
— ——
mmrnmmm
mmrnmmm
mmrnmmm
3 .8
2 .7
3.1
1 .1
1 .5
0 .5
9 .8
2 .6
4 .7 *
1 .7 *
1 7 .5
5 .7
1 3 .3
5 .7
1 1 .3
7 .0
19.1
8 .9
1 5 .3 *
6 .8 *
♦T otals in these colum ns are averages of the sums of th e to tals shown for each of th e four so il types,
DEEP
GRAVELLY
LOAM
DEEP
LOAM
RELICT
SHALLOW
LOAM
AREA
C, viscidiflorus
GRAZED
FIG.
3.
PASTURE
PERCENTAGE COMPOSITION OF MAJOR PLANTS BY SOIL TYPES,
SANDY
LOAM
- 1 6 -
FIG . 4.
FIG.
5.
AGROPYRON-BOA TYPE ON DEEP LOAM SOIL.
AGROPYRON-POA TYPE ON DEEP GRAVELLY LOAM SOIL.
IS p e rc e n t
on t h e s h a l l o w l o a m
sandy loam
(Fig.
7).
In c o n t r a s t ,
form ing' 3 . 4 p e r c e n t of the
deep
the
gravelly loam ,
deep
and
C.
and deep
forming
sandy loam
together
soils.
low ed the
9.0
on t h e
same trend
percent
as A.
on th e
compared
from 10,6
from
to 6 . 8
percent;
however,
of 5 . 1
A.
on th e r e l i c t
deep
sandy loam ,
p e r c e n t bn t h e
deep
soil.
The
percent;
d e n s i t y of t h e
spicatum
_P.
p e r c e n t to 0 . 4 p e r c e n t ,
grazed pasture
grasses dropp
d ecreased in density
secunda from
p e r c e n t to 2 .8
percent
2.2
percent
Stipa co m ata,
percent,
composing
c o m p a r e d to 4 , 0 p e r c e n t
area.
D e n s i t y of shrubs
gely
oh t h e
soil.
p e r c e n t on t h e s h a l l o w l o a m ,
. A g ro p y r o n
p e r c e n t to 0 . 9
vegetation
smithii
density,
on t h e r e l i c t a r e a was 1 5 . 3
i n c r e a s e d in d e n s ity from 0 . 6
p e r c e n t of th e
1.5
up 9 .1
deep sandy'loam
from 1.1
A.
Chrysothamnus viscidiflorus fol-
grazed area.
percent..
p e r c e n t of th e t o t a l
making
gravelly loam,
smithii
was m o s t a b u n d a n t on t h e s h a l ­
a n d i t was a m i n o r c o m p o n e n t of t h e
spicatum ,
p e r c e n t on th e
p e r c e n t on t h e
a n d 3 2 . 9 p e r c e n t on
d o m i n a n t p l a n t on t h e
of th e v e g e t a t i o n
p e r c e n t to 5 . 2
an a v e r a g e
to 0 . 6
33,3
density
5.3
on t h e s h a l l o w l o a m
soil types.
a n d i t was n o t e n c o u n t e r e d on t h e
The total
shallow loam ,
of d o m i n a n c e
other three
secunda increased,
deep loam ,
m a k i n g up 4 4 . 2
E_. I a n a t a w a s t h e
o f P.
on t h e d e e p
The two rhizom atous grasses,
45 p e r c e n t of t h e v e g e t a t i o n ,
communities
loam,
the im p o rta n ce
p e r c e n t on t h e
greatest degree
Of t h e s h r u b s ,
and was not r e c o r d e d
Stipa co m ata likewise
m ontanensis,
assum ed the
6),
v e g e t a t i o n , on t h e
13.2
sandy lo am ,
low l o a m
(Fig.
a n d f orbs
declined
as a r e s u l t of t h e r e d u c t i o n i n v i g o r
nificant decline
in d en s ity
from 2 .2
from
4.7
p e r c e n t to 1 . 7
percent lar­
o f jE. l a n a t a , w h i c h s u f f e r e d a s i g ­
p e r c e n t to 0 . 5
percent.
The cover
of
— 18 —
FIG.
6.
EDAPHIC CLIMAX OF RHIZOMATOUS GRASSES OCCUPYING DEPRESSION IN CENTER
FOREGROUND, WITH AGROPYRON- POA TYPE IN IMMEDIATE FOREGROUND, ON
SHALLOW LOAM SOIL.
FIG.
7.
EROTIA-POA TYPE ON DEEP SANDY LOAM SOIL.
19
Co v i s c i d i f l o r . n s a v e r a g e d s l i g h t l y l e s s o n t h e
ed,
but because
of th e r e d u c t i o n
up 7 .3 p e r c e n t of the
in t o t a l
vegetation
on t h e
grazed area than
density,
on th e u n g r a z ­
this u n p a la ta b le
shrub m a d e
g r a z e d a r e a as c o m p a r e d to 4. 5 p e r ­
c e n t on the u n g ra z e d .
The
clim atic
clim ax
of a n y g iv e n r e g i o n is g e n e r a l l y c o n s i d e r e d to o c c u ­
py the m o s t m a t u r e
soils.
one m a y r e c o g n iz e
edaphic
As a r e s u l t o f e d a p h i c
and topographic
and topographic
variations,
clim axes w ithin the region
(Odum,
1953).
Following this sch em e,
a r e a was th e
deep loam
this soil was th e
(Tisdale,
spicatum
type,
clim atic
zone in ^ so u theastern
1947).
the
Washington
the
infrequently
deep loam
getation
Two
A g ro p y ro n - Poa type w hich
This type
(Daubenm ire,
is s i m i l a r to t h e
The
Montana.
occupied
A g r o p y r o n - Po,a
1942) and in British
a sim ilar
Agropyron
d escrib ed by T is d a le ,
and Wright and
gravelly loam
Wright,
grasslands
only s ig n ific a n t "difference in co m m u n ity
and deep
Columbia
K o ele ri a c r i s t a t a was an im p o r t a n t
e n c o u n t e r e d in the low e l e v a t i o n
of B e a ­
composition
soils was th e low er to t a l
on
d e n s i t y of v e ­
on t h e l a t t e r t y p e .
edaphic
climaxes
w ere r e c o g n iz e d in the
loam
soil
loam
a E u r o t i a - Po a t y p e was
a C alam agrostis- Agropyron type
The dom inance
on th e sh a llo w l o a m
pure
soil w h ic h oc c u r e d in the study
Wright and Wright (1948) described
c o m p o n e n t of th e v e g e t a t i o n
verhead Valley.
and the
clim ax.
type in southw estern
but has been
most m ature
study are a.
was f o u n d ,
On t h e s h a l l o w
and on th e
deep sandy
evident.
of t h e r h i z o m a t o u s
grasses,
soil was a t t r i b u t e d to th e
C^_ m o n t a n e n s i s
a n d A.
fact that they formed
stands in the depressions where runoff water
accum ulated.
smithii,
almost
However,
20 where
additional
much like
m o is tu re was n o t r e c e i v e d ,
t h a t d e s c r ib e d for the
The E u ro tia- Poa type
the
area.
deep loam
of this
extensive
into
the buried
fibrous roots
o f JE.
driest and most im m a tu re
buried
lanata,
clay loam portion.
a f f o rd e d by the
clay loam profile
the. m a j o r
Because
of t h e
s a n d y s u r f a c e h o r i z o n , _E. l a n a t a
cesses well into the
summer
dry seaso n ,
dominant,
deep
utilizing
the
cupied
s e c u n d a , whose shallow root system
clay loam ,
f o u n d on t h i s s o i l ,
V).
of th e
The clim a x
com munities
winter precipitation
is t h e
climax vegetation.
dominants
owing season te m p eratu re s
clim atic
However,
(Table
grass
G re at Basin r e g i o n ,
factor
controlling the
in B e a v e r h e a d V a lle y th e
may be the
are
cha­
where
development
m ajority
and summer m onths.
in B e a v e r h e a d V a ll e y
clim ax. ■
of t h e stu d y a r e a w e r e
to th a t o c c u r rin g in the
a n d i t is f e l t t h a t t h i s
m e n t of a b u n c h
plant
and L appula sp. were
of the
during the spring
d i s t r i b u t i o n is s i m i l a r
Plains region
did not extend into
o f " W i n t e r f a t 11 t y p e s i n t h e s o u t h ­
of t h e r e l i c t p o r t i o n
major
t h e p r e c i p i t a t i o n is r e c e i v e d
of m o i s t u r e
o f _E. l a n a t a w e r e o c ­
N o rth ern D ese rt Shrub F o r m a tio n in U ta h .
r a c t e r i z e d by sp e cie s w h ich are
of th e
its growth p r o ­
abundant interstitial
( 1 9 4 0 ) n o t e d t h a t _E_. l a n a t a
a s s o c i a t e d sp e c ie s in s e c o n d a ry su c ce ssio n s
I).
extended well
a l t h o u g h i t was n o t a b u n d a n t on a n y o t h e r s o i l t y p e
Shantz and P iem eisel
ern p o r tio n
the plants
L a p p u la re d o w sk ii was a n o th e r
(Table
m o i s t u r e stor'ed in th e
The in te rstic e s b etw e en
the
soil in
moisture penetration
can continue
buried soil p ro file.
m a i n l y by P.
c o m p o s i t i o n was
soil was c o n f i n e d to the u p p e r two f e e t;
b e l o w t h a t d e p t h was a w e l l - d e v e l o p e d ,
The
com munity
soil.
was f o u n d on t h e
The sandy nature
the
of
This type
Great Plains.
Gr­
co o ler th a n in the G reat
factor
co n tro llin g the develop
21
FIG.
When the
species
8.
com petition
of p l a n t s
typical
UNION PACIFIC RIGHT-OF-W AY.
of t h e
of t h e
clim ax plants
Mixed
Prairie
ci i m ax d o m i n a t e d by S t i p a
com ata results.
of v e g e t a t i o n
elevations
In s o m e
on t h e l o w e r
areas
interspersed with
com munities
Bouteloua
com munities
the
occur
Stipa
gracilis reaches
author
this
grass was p r e s e n t ,
sandy
soils.
textured,
the
road rig h t-o f-w ay
S_. c o m a t a
areas
short grass d i s c l i m a x .
the
Figure
12 m i l e s
on t h e r i g h t - o f - w a y
catum
of p l a n t s
i s A_.
has b ee n p r a c t i c a l l y
loam
I.
Generally
soils ( T a b le
elim inated
are
these
V).
in B e a v e r h e a d
g raz in g was p r a c t i c e d
County.
in areas where
on g r a v e l l y
or
A g r o p y r o n - P oa t y p e is c o n v e r t e d
of D i l l o n ,
spicatum .
type
Valley.
of its r a n g e
8 is a p h o t o g r a p h
north
most widespread
w a s r e p l a c e d b y B_. g r a c i l i s
original
and a dis­
d o m i n a t e d b y _C_. v i s c i d i f l o r u s
deep,
limits
in d en s ity ,
T h i s is t h e
in B e a v e rh e a d
o b se rv e d th a t if very h e a v y
On s u c h
increase
a s p e c t as s h o w n i n F i g u r e
on m e d i u m
The
is r e d u c e d b y o v e r g r a z i n g ,
of the
Montana,
Union
The
vegetation
Rail­
abundant plant
On t h e h e a v i l y - g r a z e d
and the
Pacific
to a
pasture,
A.
is e s s e n t i a l l y
spia
22 pure
s t a n d o f J3.
gracilis.
•SUMMARY
'
The d a t a p r e s e n te d in this study show t h a t the
lower
elevation
grassland
bunch
grass p r a i r i e
clim ax vegetation
of B e a v e r h e a d V a l l e y in s o u t h w e s t e r n
d o m in a te d by Agropyron s p i c a t u m .
of t h i s
a r e a is t h e
A gropyron- Poa type
s .o ils .
Two ed a p h ic
o t i a - Poa ty p e were
climaxes:
occurring
The
on t h e
M o n t a n a is a
clim atic
mature
climax
deep loam
A C a la m a g ro stis - Agropyron type
found on a s h a l l o w . l o a m
of th e
and a Eur-
and a deep sandy lo a m
soil res­
pectively.
It is e v i d e n t t h a t as a r e s u l t of h e a v y
grazing the
original bunch
p r a i r i e has b e e n l a r g e l y r e p l a c e d by a grazing d i s c l i m a x
com ata.
and th a t if h ea v ie r
l a c e d by a short grass
gravelly soils.
g r a z i n g is p r a c t i c e d
florus occur in th e -d is c lim a x ,
of p l a n t s
■
d o m i n a t e d by S tip a
this d i s c l i m a x w ill be r e p ­
d i s c l i m a x d o m i n a t e d by B o u te lo u a g r a c ilis
Communities
grass
on s a n d y or
d o m i n a t e d by C h r y s o t h a m n u s v i s c i d i -
g e n e r a l l y on m e d i u m
textured,
deep loam
soils.
LITERATURE
Clarke,
S.E.,
J . A. C a m p b e l l
grazing c a p a c ity
Saskatchewan
Cooper,
H.W .
Tensleep,
189
a n d J . B. C a m p b e l l .
stu d y of t h e n a t i v e
and M anitoba.
1953.
Amounts
Wyoming,
CITED
Dom.
I 9 42.
An e c o l o g i c a l
grass p astu re s in so u th e rn
Can. Dept,
Agr.
Tech,
Alberta,
Bul.
of big s a g e b r u s h in p l a n t c o m m u n i t i e s
as a f f e c t e d b y g r a z i n g t r e a t m e n t .
Ecology
and
54.
31 p p
near
34:1 8 6 -
23
Daub enm ii e ,
R . F.
1942.
ern W a sh in g to n
Morris,
M.S.
An e c o l o g i c a l
and a d ja c e n t Idaho.
1 946.
E0 P.
1953.
delphia.
Reitz,
L. P .
plants
Tisdale,
1947.
C.
clim ate.
H . L.
Valley,
Mont.
for t h e
Acad.
of E c o l o g y .
12:53-79.
classification
Sci.
of M o n t a n a
6:41-44.
W.B.Saunders
Company,
Phila
1 939.
The
Mont.
grasslands
Geog.
1948.
Rev.
a n d R . L.
Utah,
Agr.
Exp t .
Sta.
Bui.
375.
of t h e s o u t h e r n i n t e r i o r
35pp.
of British
CoIum
$
28:346-382.
W.
Im p o rta n t grasses and other com m o n
An a p p r o a c h
toward a rational
classification
of
38:55-94.
Piemeisel.
as i n d i c a t o r s
1940.
of soil
T y p e s of v e g e t a t i o n
conditions.
U .S.D .A .
in E sca la n te
Tech.
Bui.
46pp.
W eaver,
J . E.
Co.,
Wright,
Morris.
on M o n t a n a r a n g e s .
Ecology
713.
Fundamentals
a n d H . E.
Thornthwaite,
Shantz,
Proc.
Monogr.
of s o u t h e a s t ­
384pp.
E. W.
bia.
Ecol.
An e c o l o g i c a l b a s i s
g rasslan d s (a s u m m a r y ) .
Odum,
stu d y of th e v e g e t a t i o n
a n d F . E.
Inc.,
J. C.
tana.
Clements.
New York.
a n d E. A.
Ecology
601
Wright.
29:449-460.
1938.
Plant Ecology.
M c G r a w - H i l l Book
pp.
1948.
Grassland types
of s o u t h
central
Mon­
B 7V M