Ecological and morphological relationships of subspecies of Peromyscus maniculatus near St. Mary,
Montana
by Ronald Jay Glazier
A thesis submitted to the Graduate Faculty in partial fulfillment of the requirements for the degree of
MASTER OF SCIENCE in Zoology
Montana State University
© Copyright by Ronald Jay Glazier (1971)
Abstract:
For a period of five months between' June 22 to September 7, 1967 and from June 27 to September 5,
1968, a live trapping study was undertaken near the St. Mary region, Glacier National Park, Montana,
to determine the ecological distribution and analyze morphological variation of two subspecies of
Peromyscus maniculatus, P_. m. artemesiae and P. m. osgoodi. Morphological measurements were
taken on adult mice only. Mean lengths of tail, ear, hind foot and skull are significantly greater in P. m,
artemesiae than P. m. osgoodi. Body length, nasal length and mastoid breadth are not reliable
measurements for distinguishing between individuals of populations of the two subspecies, Nine
individuals of intermediate measurements are classified as suspected hybrids.
Three general habitats are found in the study area, grassland, aspen groveland and coniferous forest.
Allopatric P.m. osgoodi populations are found in the grasslands and meadows and disturbed areas of
the aspen groveland. Allopatric P_. m. artemesiae populations are found in the coniferous forest and
the meadows in that forest. The sympatric area corresponds roughly to the narrow
groveland-coniferous forest ecotone. Regardless of general habitat the mice are found in those areas
where ground vegetation is light but places for concealment are abundant. Although contact was found
between the subspecies in three areas, contact in general appears to be limited by the dense vegetation
along the sympatric contact line. Hybrids may occur, but they are limited in number. Isolating
mechanisms other than habitat selection may be involved. In presenting'this thesis in p a r t i a l fulfillment of t he require^
'ments for an a d v a n c e d degree at -Montana ,'State U n i versity, I .agree that
the .Library■shall make it freely a v a i lable for inspection.
I- further
agree that permis s i o n for extensive copying of t h i s . t h e s i s for scholarly
purposes m a y be g r a n t e d b y m y major,, p r o f e s s o r , or-, i n ‘his a b s e n c e , b y
the Direc t o r of.Libraries.
It is u n d e r s t o o d t h a t •any copy i n g or p u b l i ­
cation.of this thesis for fin a ncial gain shall .not. be,- allowed--witho'ut
m y written'permission.
E C O L O G I C A L A E D M O R P H O L O G I C A L . R E L A T I O N S H I P S OF SUBSPECIES
OF P E R O M Y S CUS MAEIC U L A T U S N E A R S T .•M A R Y , M O N T A N A
by
RONALD J A Y GLAZIER
A thesis submitted to the Graduate Facu l t y in p a r t i a l ■
fulfillment of the requirements for the degree
of
M A S T E R OF SCIENCE
in
Zoology
Approved:
Head, M a j o r Department
Chairman, E x a m ining Committee
Gradudte Dean
. M O N T A N A STATE U NIVERSITY
Bozeman, Montana
M a r c h , 1971
iii
-A c k n o w l e d g m e n t s
I w o u l d like to acknowle d g e Dr. Robert E. M o o r e for h is valuable
assistance in guiding this research and h e l p f u l suggestions in p r e p aring
the manuscript.
I w o u l d also like to t h a n k Dr. P a l m e r D. Skaar and Dr.
Don C. Q uimby for their critical reading and s u g g e s t i o n s . In addition
I am indebted to Dr. J o h n H. Rumely for his assistance in classification
of plant communities in the study area.
Al s o Francis Elmore, chief
natura l i s t . a t Glacier N a t i o n a l Park, and pe r s o n n e l of the N a t i o n a l P a r k
Service are to b e thanked for their c o o peration in a llowing m e to conduct
m y research w i t h i n the p a r k b o u n d a r i e s . Some fi n a n c i a l assistance was
provi d e d b y the N a t i o n a l Scie n c e Foundation, Research Grant GB-5934, and
by the D epartment of Zoology and Entomology.
I am also grateful to my
wife, K a r e n , for typing the manuscript.
Table of Contents
Page
V i t a
• • • • • • • • ♦
Q*b&*ba**bbba&*&*ca»ab*b&*»*t**&Abb***»***b*
iii
@ b @ o o * o b bObOb**ab@@»6***oobboob o*ob6bob****b*o*b*#
v
Acknowledgments
LlSt Of Tables
List of Figures
Abstract
Methods
6 6 0 6 6 6 0 6 6
6 "6 6 6 6 6
I
'
O O O O O O O O O O O O O O O O O e O O O O O O O O O O O O O O O O O O O O O O O O O O A O O O O O O O O O O O O
General A r e a
3
ooooooooooooooooooooooooeooo,ooooooooooo
5
o o o ooooooooooooeooooooooooooooo ooooooooooooooooooo
5
Collection Sites
O 66666
6 6 6 6 6 6 6 6 6 6 6 0 6 6 6 6 6 6 6 0 8 6 6 6 6
9
6 6 0 6 6 6 1 1 6 6 6 6 6 6 6
17
6 6 6 6 6 6 6 6 6 6 6 6 6 0 6 0 6 0 6 0 6 6 6 6 0 0 6 6 6 6 6 6 6 6 6 6 0 6 0 6 6 6 0 6 6 0 6 0 6 6 0 6 6 6 6 6 6
Morph o l o g i c a l Variation
0 6 6 6 6 6 6 6 0 6 6 6 6 6 6 6 6 6 6 6 6 6 6 0 6 6 6 0 6 6 6 6 6 6 6 6 6 6 6
E cological Distr i b u t i o n
6 0 0 6 6 6 6 6 6 0 0 6
D iscussion
v ii ■
O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O C
Descr i p t i o n of Study A r e a
Results
vi
O e e 6 6 0 0 6 6 6 0 C 0 6 6 6 6 6 » 6 o e 6 6 6 6 e » 6 e 6 6 6 d b l l 6 a e 6
O O O O O O O O O O O O O O O O O O a O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O
Introduction
ii
• ■ • d o o o o o o e o e o t i s &o&etittedboeeeeoeoocoeeeeeeea eeeeee*
■ 17
6 6 6 6 6 6 0 6 6 0 6 0 0 6 6 0 6 6 6 6 6 6 6 0 6 6
28
0 6 6 0 0 6 0 0 6 0 6 6 0 0 0 0 6 6 0 0 6 6 0 0 0 0 6 6 0 6 0 6 0 0 6 6 6 6 6 0 6 0 0 0 0 0 0 0 6 0 0 6 0 0
33
Literature Cited
6
6 6 6 6 6 6 0 0 6 6 0 6 0 0 6 0 0 0 0 0 0 0 0 6 6 0 6 6 6 0 6 6 6 6 0 0 0 0 0
6 0 0 6
0 6 6 0
6
39
V
List of Tables
Table
II.
. III.
IV.
V.
VI.
VII.
VIII.
Page
Means and ranges of b o d y m e a s u r e m e n t s of p o p u l a t i o n
samples of Peromyscus m a n i c u l a t u s osgoodi and
Peromyscus m aniculat u s arternesiae ....................
18
Means and ranges of skull m e a s u r e m e n t s of p o p u l a t i o n
samples of Peromyscus m a n i c u l a t u s osgoodi and
Peromyscus m aniculat u s a r t emesiae ....................
19
Results of the m o d i f i e d D u ncan n e w m ultiple range test
showing significant differences b e t w e e n p o p u l a t i o n
sample means of tail lengths and h i n d foot lengths:... '
20
Results of the m o d i f i e d D u n c a n n e w m u ltiple range test
showing significant differences b e t w e e n p o p u l a t i o n
sample means of ear l e ngth . . . . . . . . . o
.
.
21
.
Results of the m o d i f i e d D u n c a n n e w m u ltiple range test
showing significant differences b e t w e e n p o p u l a t i o n
sample means of the greatest l e n g t h of the skull and
nasal l ength .....O......................... ..........
22
Results of the m o d i f i e d D u ncan n e w m u ltiple range test
showing significant differences betw e e n p o p u l a t i o n
sample means of b o d y l e n g t h an d m a s t o i d b r e a d t h ......
23
S e l e c t e d b o d y a n d skull mea s u r e m e n t s of s u s p ected
Iiybrids
O v erall t r a pping success for t he t wo subspecies i n each
area sampled.
The totals incl u d e those m i c e u s e d for
m o r p h o l o g i c a l measur e m e n t s ...........................
29-30
vi
List of Figures
Figure
Page
Lo
Map of the stutiy area
o■o eoooooooooooooooo*oooooooooooooo»ooo
2.
R o a d t e d at D u c k Lake
...................
3 o
D i s t u r b e d a s p e n grovelan d • at W i n d y Creek ,, , , « , .
4.
A s p e n g r o v eland meadow, St, M a r y Lake
5«
M e a d o w in spruce-fir forest at Goat M o u n t a i n
6.
Serai stage Douglas fir forest at B a r i n g Creek site
To
Geographic v a r i ation in means of t a i l lengths of ]?.
r n amculatus across M o n t a n a o o o o , o , o o o o , , o o * o , , o , o ,
,o
^
10
. , ,
.. .......................
10
.. ........
13
o . «
,
13
,
o , , , o o o ,
l6
3‘5
I
Abstract
For a p e r i o d of five months between' June 22 to Se p t e m b e r T 5 19^7 5,
and from June 27 to September 9, 1968, a live t r a p p i n g study was u n d e r ­
taken near the St. M a r y .r e g i o n 5 Glacier Nat i o n a l Park, M o n t a n a 5 to
determine the ecological dist r ibution and analyze m o r p h o l o g i c a l v a r i a t i o n
of two subspecies of Peromysc u s m a n i c u l a t u s , P_» m. art erne siae and ]?. au
o s g o o d i . M o r p h o l o g i c a l measu rements w e r e taken on adult m i c e only.
Mean
lengths of tail, ear, h i n d foot and skull a r e .sig n i f i c a n t l y greater in
Pi. m, art erne siae than P. m. o s g o o d i . B o d y l e n g t h , n a s a l l e n g t h and
m a s t o i d b r e a d t h are not relia b l e . m e a s u r e m e n t s for d i s t i n g u i s h i n g b e t w e e n
individuals of p o p u l a t i o n s ■of the tw o s u b s p e c i e s , Ni n e individuals of
intermediate m e asurements are c l a s s i f i e d as suspected h y b r i d s .
Three general habitats are f o u n d in the study area, grassland, aspen
g r o v e l a n d and coniferous forest.
Allop a t r i c P» m. osgoodi populations are
found in the grasslands and mead o w s a nd d i s turbed areas of the aspen
groveland.
Allopatric P_. m, arternesiae populations are found in the
coniferous forest and the meadows in that f o r e s t „ The sympatric area
corresponds roughly to the n a r r o w groveland- c o n i f e r o u s forest ecotone.
Regardless of general habitat the m i c e are found in those areas where
ground vegeta t i o n is light but places for concealment are abundant.
Al­
t h o u g h contact was found b e tw e e n the subspecies in t h r e e areas, contact
in general appears to be limi t e d b y the dense v e g e t a t i o n along the
sympatric contact l i n e . . Hybrids m a y occur, but t h e y are limited in
n u m b e r . Isolating mechanisms other th a n habitat selection m a y be
involved.
IntroductionWhen, the end-populations of a circular chain of i n t e r grading -sub­
species -overlap and become sympatric w i t h o u t - i n t e r b r e e d i n g ,
has been demons t r a t e d (M a y r , 1963)-
speciation
T hese circular overlaps have be e n
u s e d as evidence for "speciation b y d i s t a n c e " , • A l t h o u g h genetic
divergence m a y be .achieved thr o u g h distance
(Wright, 1 9 ^ 3 ) gene fl o w a nd .
genetic homeostasis t e n d to limit the a m o u n t 'of genetic d i v e r g e n c e »
In
most ■of the w e l l - a n a l y z e d cases of circular overlap t he populations -are',
not continuous but have m a j o r gaps in the chains or at least show evidence
for the former existence of- such gaps
(M a y r , 1963-)»
The deer mouse,
Peromyscus m a n i c u l a t u s , has' also b e e n c i t e d as an example of circular
overlap
(Dice, 1931 and M a y r , 1942) »
In the n o r thern part of lower M i c h i g a n two subspecies j-'P. m, g r a c i l i s 1
and .R. m, b a i r d i i , are sympatric wit h o u t
showing: evidence of- inter­
breeding.
This occurs becaus e the t wo continue to- r e main ecologically
separated;
gracilis lives in dense m i x e d forests of beech, maple, y e l l o w
b i r c h and a ssociated t r e e s , .while b a i r d i i prefers prairies,
and.lake beaches .(Hooper-, 1942) „
open fields -
Repr o d u c t i v e is o l a t i o n was., most like l y
o riginally a c c o m p lished-by the extrinsic means of a g e o g r a p h i c barrier,
but n o w is m a i n t a i n e d in,areas of s y mpatry b y "habitat i s o l ation (M a y r ,1963. and- Meechan., .1 9 6 1 )4
The r a n g es.of two other subspecies, P_, m. ■art ernes i a e . and P. m.
o s g o o d i , overlap along the eastern edge of-^Glacier'-National Park.
Morpho­
logical evidence collected -by O s g o o d (1^09) and M u r i e (1933)'suggests no
hybridization.
■The"subspecie s artemesiae is a long-ta i l e d - f o r e s t fo r m ■
—2—
while osgopdi is a short-tailed g r a s s l a n d form, each b e i n g closely
^ restricted to their respective h abitats
(M u r i e , 1933).
K n o w ledge of th e
overlap in Glacier N a t i o n a l Park was origi n a l l y b a s e d on data from O s g o o d
(1909), who states that P_, m. art erne siae i n t ergraded to the south w i t h
P. m.
s o n o r i e n s i s , w h i c h is t h e o r e t i c a l l y connected g e n e t i c a l l y to the
east w i t h . P » m. r u f i n u s , and finally w i t h P. m. o s g o o d i .
Murie
(1933) b a s e d his conclusion that no h y b r i d i z a t i o n occurred from
the data collected on a small area, m o s t of w h i c h lies in or near the
sympatric area.
Murie gave no infor m a t i o n on either t he pat t e r n of
m o r p h o l o g i c a l v a r i ation among individuals of populations of mice or the
local d i stribution of mice in specific habitats in the area.
For a total of five months d u ring the summers of 1967 and 1968, I
conducted a live-t r a p p i n g study of P. manic u l a t u s near St. Mary,
Montana.
The objectives were
(l) to m e a s u r e m o r p h o l o g i c a l 'variation of
each subspecies t r a p p e d from a series of populations e x t e n d i n g across the
sympatric zone, and (2) to determine the ecological distribution of the
subspecies arternesiae and osgoodi in allopatric and sympatric areas
near the St. M a r y region.
Meth o d s
A l l mice used in this study w e r e
captured in Sherman live-traps.
T r a p p i n g w a s conducted from June 22 to September 7, 1967, and from June
27 to September 5, 1968.
The tra p p i n g sites w e r e located in the diverse
h a b i t a t s of the St. M a r y and Swif t c u r r e n t drainages and on the pra i r i e •
south of D u c k L a k e . • T h e s e areas i ncluded the sympatric zone and adjacent
allopatric areas of the two subspecies of mice.
M i c e w e r e collected for
m o r p h o l o g i c a l comparisons from eight sites w i t h i n the m a j o r habitats
the area, .grassland,
aspen groveland and s p r u c e - f i r forest.
in
In each of
these collection sites an attempt w a s m a d e to obtain twenty m i c e for
m o r p h o l o g i c a l comparisons.
However,
if a fter 400 t r a p-nights less,than
fifteen m i c e w e r e captured,
trapping at that site w a s d i s c o n t i n u e d . '
T h e criteria used in ass i gning m i c e to either of the two subspecies
w e r e those m o r p h o l o g i c a l measu rements
Osgood
(1909)
of tail and ear lengths as us e d b y
in his revision of the genus P e r o m y s c u s .
Individuals
w h o s e tail and ear length m e as u r e m e n t s w e r e intermediate of those d e s ­
cribed for the two subspecies w e r e tentatively classified according to
the classification of the pop u l a t i o n in w h i c h they w e r e trapped.
In addition to the eight areas s a m p l e d s p e c i f i c a l l y as collection
sites, other habitats w e r e sam p l e d to determine the l ocal distribution of
each subspecies and to delineate the sy m p a t r i c zone.
The traps were
p laced so as to sample as m a n y h a b i t a t s in each area as practicable.
/
Trap lines w e r e extended, w h e r e v e r possible,
ecotone.
A relative index of subspecies
across the forest-gr a s s l a n d
found in each h a b i t a t was
—4—
computed as a p ercentage b a s e d on the n u m b e r of mi c e caught per 100 trap
nights.
E a c h h a bitat
trapped w a s e x a m i n e d qualitatively and then described
according to g e neral vegetati o n cover an d community type wi t h reference
to H a b e c k
("1968) , K i r k w o o d
(1922)
and Lynch
for plants f o llow B o o t h and W r ight
animals, Hall and K e l s o n
(1962)
(1955) .
and Booth
S c i e n t i f i c names
(1950)
and for ■
(1959).
M i c e used for m o r p h o l o g i c a l comparisons w e r e m a i n t a i n e d in a l a bora­
tory at M o n t a n a State Univer s i t y for at least eight months,
age for adult classification
(Sheppe,
1963).
Standard m e asurements of total length,
tail length,
and right ear length w e r e recorded to the nearest 0.5 mm.
ments w e r e taken from dead animals.
m u s e u m specimens.
mastoid breadth
the m i n i m u m
right hi n d foot
All m e a s u r e ­
Skins and skulls w e r e prepared as
Greatest length of the skull, n a s a l length and
(Hoffman and P a t t i e , 1968)
twice to the n e arest
for each s k u l l w e r e m e a s u r e d
.05 m m u s i n g a dial caliper.
T h e s e measurements
h a v e p o s sible value in distin g u i s h i n g subspecies.
A m o d i f i c a t i o n of Duncan's n e w m u l t i p l e range test w a s used to test
differences
in means of samples w i t h une q u a l size
( K r a m e r , 1956).
Description of Study Area
General A r e a
The study area^was l o cat e d in the St. Ma r y an d Swiftcurrent drainages
)
on the eastern side of Glapier N a t i o n a l Park, Montana,
south of D u c k Lake
(Fig. l).
an d on the pra i r i e
St. M a r y and Swiftcurrent valleys extend
from the continential divide to the edge of the m o u n t a i n range twen t y
m i l e s to the! east, a n d are gla c ially carved.
Bo t h are r e l a t i v e l y n a r r o w
w i t h the surrounding mountain s r i s i n g to 9,000- feet. ■ A t.t he eastern p a r k
b o u n d a r y the S t ,. M a r y v alley widens, turns n o r t h w a r d a nd is bounded-on.
the east b y a lateral m o raine known as the St. Ma r y R idge
( F i g . ,1).
This-
ridge r i s e s ■steeply approximat e l y 1,500 feet above t h e 4,500 foot e l e v a ­
tion of-the valley.
The eastern slope of the moraine gives w a y g r a dually
to the r o lling hills of the Great P l a i n s .
Duck Lake is a p proximately
three miles east of --Babb arid lies in a depre s s i o n in the,St. M a r y R i d g e .
' The-to p o g r a p h y of -the pa r k is a t t r i b u t e d -largely to the action of .
glaciers.
During,the Pleisto c e n e th e park,- except the summits of the
h i g h e s t - p e a k s , was completely covered b y glaciers.
completely r e m o v e d the forest fr o m t h e p a r k area.
These glaciers'
It h a s been only in
the last 9,000 years that the area has b e e n r e v e g e t a t e d (Dyson, i960) a nd
the invasion- and e stablishment - o f a n imal populations .has t a k e n place.
Three m a j o r vegeta t i o n types are f o u n d w i t h i n the. study area.
g r a s sland community of needlegrass
(S t i p a ) and fescue
The
(F e s t u c a ) south a n d ;
east of Duck Lake is a w e s t e r n e x t e n s i o n . o f the Great -Plains.■ Aspen
g r o v eland .(Lynch., 1955') consisting of a n a r r o w zone of -grove-grassland .
mosaic b e t w e e n t h e .f o r ested eastern front of the m o u n t a i n s and the Great
/
- D -
L E G E N D
mu
C o n ife ro u s
■
Cl
A spen
X
fo re s t
g r o v e la n d
P ra irie
C o lle c tin g
E n tra n c e
s ite s
g a te s
Scale
Fig.
I Map of the study area
-7Plains is found along b o t h sides o f ■L o w e r St... M a r y Lake.
It continues
along the west side of St, M a r y Lake for three and..one-half m i l e s ,
I so­
l ated -stands of aspen grove l a n d .are f o u n d -farther u p t he v a l l e y (Fig,
l).
This zone is relati v e l y narrow, along St. M a r y .L a k e , ex t e n d i n g .not more
than one mile f r o m the lake e d g e ,
A similar condition exists on -the
.
n o r t h side of Swiftcurrent Creek and Lake Sherburne in t he Swiftcurrent
drainage.
Quaking aspen (Populus tremuloid.es) is. the dominant tree;
b l a c k cottonwood (P,. t r i c h o c a r p a ) and n a r r o w l e a f c o t t o n w o o d ■(?»■
a ugusti f o l i a ) are also p r e s e n t .
edges of streams.
Grasses,
The -latter species is r e s t r i c t e d to th e ■
shrubs a nd forbs make up a v e r y dense u n d e r ­
growth in the aspen groves, pa r t i c u l a r l y in mesic s i t e s .
B u f f aloberry
(Shepherdja a r g e n t e a ), w e s t e r n s e r v i ceberry (A m e l a n c h i e r a l n i f o l i a ),
shrubby cinquefoil
(P o t e n t i l l a f r u i t i c o s a ) a n d -chokecherry (Prunus .
v i r g i n i a n a ) are the dominant shrubs- in this area.
B l u e b u n c h wheatgrass
(Agropyron spicat-um) , b l u e s t e m (A. -smithii) and b l u e b u n c h fescue '(F e s t u c a .
i d a h o e n s i s ) are common grasses, found i n the- g r a s sland adjacent t o aspen
groves.
Lynch
(1955) l i s t s r ough fescue
climatic climax grass of the groveland.-
(Fes t u c a s c a b r e l l a ) as the
Conifers a s s o c i a t e d wi t h the
groveland are relati v e l y unimportant except along the w e s t e r n border a nd .
on St. M a r y Ridge where the gr o v e l a n d nifeets montane, coniferous f o r e s t ,.
Here E n g e l m a n n spruce
(P i c e a engelmanni )■, Douglas fir
m e n z i e s i i ■ and lodgepole pine
(Pseu d o t s u g a
(Pinus c o n t o r t a ) are s c a t t e r e d through the-
aspen -stands, and adjacent grasslands,
A t -higher e l e v a t i o n s (4,800 ft.) t he aspen - g r o v e l a n d is rep l a c e d tiy
8the coniferous f o r e s t ■ Two zones cha r a c t e r i z e d b y D a u h e n m i r e
(19^3-) are '
r e p r e s e n t e d here, the Douglas .fir zone and the s pruce-fir zone.
In the
study apea the dominant, trees are Douglas fir and lo d g e p o l e pine along
w i t h some limber pine '(Pinus f l e x j l i s ) on exposed r i d g e s . .Above a p p r o x i ­
m a t e l y 5 »500 feet and i n favorable sites the dominant trees are Engelmann-.
spruce and alpine fir
(Abies, l a s i o c a r p a ).
The forest in most of'the study
area, appears to be a serai stage forest w i ^ h the. you,ng g r o w t h being
m o s t l y E n g e l m a n n spruce and alpine fir.
However, on some of the more
e x posed areas Douglas fir and lodgepole pi n e are r e p l a c i n g t h e m s e l v e s .
-9Collectien sites
•D1
u|
c k.
; Mopt of the t r a ppi n g "was co n d u c t e d along a ridge a p proximately
one mile south of D u c k Lake
(Fig. I).
Jitowever, some t r a p p i n g was done on
the prairie b e t w e e n the ridge and D u c k Lake.
A l o n g the ridge crest is an
©Id r o a d b e d which.is r a i s e d slightly above the surr o u n d i n g ground.
A
n a i r o w strip of g r ound along the r o a d b e d is covered w i t h rocks and a f ew
small shrubs
(Fig. 2).
B y contrast, t he surrounding p r a i r i e has very
few rocks on the surface and only an occasi o n a l s h r u b ,
Shrubby c inquefoil
is the common shrub along the ro a d b e d , . The prairie grass is most l y
needlegyass
(Stjpa' spp) but b l u e b u n c h fescue ife also present.
cjowuy chess brome
However,
(Bromus t e c t o r u m ) % m e a d o w foxtail (A lopecurus
p r a t e n s i s ) and b a r l e y
(H o r d e u m spp) are dominant along th e disturbed
■edges of the r o a d bed.
These grasses are commonly f o u n d in wasteplaces
(Booth, 1950).
■Babb-; This site is just north of U.S.
a mil© southeast of Babb
(Fig. l ) .
89 a p p r o x imately three-quarters of
The tr a p p i n g area encompasses an
a b a n doned gravel pit and the surro u n d i n g field.
The g r a v e l pit consists
of oiitwash gravel covered b y grasses a nd l ow s h r u b s ,
B l u e b u n c h fescue
and b l u e s t e m are the dominant grasses in the gravel pit a nd nearby field.
Common spowberry
(Sympjaoricargos a j b u s ) is a common shrub in the field.
Showy point v e t c h (Oxytropis s p l e n d e n s ), w a y y l e a f t h i s t l e
(Cirsuum
u n d u l a t u m ) and spotted k n a p w e e d (C e n taurea m a c u l o s a ) are important weeds
in the gravel pit.
Some shrubby aspen is scattered across the gravel pit.
-10-
Fig« 3
D i s t urbed aspen gr o v e l a n d at W indy Creek
-11-
A l t h o u g h t h e 1surrounding fields are grass covered,
about one half of the
g round cover consists of forbs,.
Windy. C r e e k : West of Babb, 1.4 .miles-west of the p a r k e ntrance on the
r o a d to M a n y Glacier is a large cl e a r i n g on the n o r t h side of the road'
(Fig. I).-
This clearing'lies in the aspen gr o v e l a n d but .has be e n
d i s t urbed b y periodic flooding of W i n d y Creek (Fig,
3).
The m a n y dry
'
rocky s tream channels w h i c h cut t h r o u g h the area give e v i d e n c e to. the
a l ternate-disturbance and p a rt i a l sta b i l i z a t i o n of.the area.
A field
layer of b l u $ b u n c h wheatgrass, b l u e b u n c h fescue, b r y o p h y t e s ,'IichenlS an d
sepetose forbs is c o vered w i t h a -discontinuous p a t c h w o r k of l o w shrubs.
Shrubs comprise approximately 50% o f th e g r o u n d cover.
Chokecherry,
b u f f a l o b e r r y and w e s t e r n serv iceberry are the most p r e v a l e n t shrubs.
Small clumps of quaking aspen are i n t e r s p e r s e d throug h o u t t he area w i t h
b l a c k cotton w o o d growing along the s t r e a m channels.
conifers are lodgepole pine and l i m b e r pine.
■
The f e w scattered
T h e area has not been
r e c ently d i s t urbed end was in a stable condition duri n g t he study period.,
AP-^ekunny C r e e k : Three miles west of t he M a n y Glacier p a r k entrance,
n o r t h ef the h i g h w a y and imme d i a t e l y west of A p p e k u n n y ■Greek (Fig.
apether t r a p p i n g site qimilar to W i n d y Creek in appearance.
I), is
However, this
.site has fewer.dry s tream channels a nd m o r e subsurface w a t p r than the
W i n d y Creek site, as indicated , b y t he h e a v i e r v e g e t a t i o n a nd the pre s e n c e
of more aspen and fescue grass.
to 100% along the stream bank.
Coverage of shrubs ranges from about 50%
-
-12'Stili M a r y L a k e ; This area is a r e l a t i v e l y n a r r o w strip of a spen-groveland
and groveland-forest eootone that p a r a llels the west shore of St. Ma r y
Lake
(Fig. l).
The zone extends f r o m the n o r t h side of W i l d Creek south-
west three and three- q u a r t e r miles along the west shore of St. Ma r y Lake.
At that point the aspen-grovel a n d is r e p l a c e d "by the Douglas fir forest.
There are several large meadows in this section (Fig.
h)
w h i c h are
separated, in the p o o r l y drai n e d areas b y bands of quak i n g aspen.
The
grass in the meadows is p r e d o m i n a t e l y b l u e b u n c h fescue a nd bluebunch
Wheatgrass.
H o w e v e r , some tim o t h y
some of the meadows.
(F h l e u m p r a t e n s e ) has be e n plan t e d in
S e r v i c e b e r r y , b u f f a l o b e r r y and snowberry are common
shrubs found in the meadows, p a r t i c u l a r l y along the margins.
cinquefoil,
silky lupine
Shrubby
(Lupinus s e r i c e u s ), arrowleaf balsamroot
(B a l s amqrrhiza sagittata.) and several other composites comprise the m a j o r
forbs,
Douglas fir and lodgepole pine are the d o m i n a n t s in the coniferous
forest w h i c h has approximately a 75-90% canopy cover.
maple
(Acer g l a b r u m ) , some quaking aspen,
and w e stern thimbleberry
understory.
cowparsnip
R o c k y m o untain
(H e r a c l e u m l a n a t u m )
(Rubus p a r y i f l o r u s ) constitute the' m ajor
■
The g r ound cover is v e r y h e a v y near the edges of the meadows
and thins out in the forest away fr o m t he meadows.
The g r ovel a n d - f o r est
ecotone is sharp throughout the area.
The b e a c h in this area is narrow,
wide and very rocky.
a p proximately t e n to twen t y feet
The. b a n k along t he b e a c h ranges f r o m about two feet
to over ten feet in height.
There is r e l a t i v e l y little v e g e t a t i o n on the
beach, but driftwood is abundant.
-13-
Fig,
Fig.
5
b
Aspen groveland meadow, St. Ma r y Lake
M e a d o w in spruce-fir forest at Goat M o untain
— 14The ! a r r o w s ; A r e e k y ridge w h i c h p r ojects into S,t» M a r y Lake west ef Roes
■ Creek forms a constriction in t he l a k e 'k n o w n as the N a r r o w s
(Fig, l ) . '
Dqier mice w e r e t r a p p e d on the yidge on the n orth side of the lake,
Douglas.' fir: and.- Iodgepole pine are the dominant trees hut ..some
• limber' pine ig found, on-the e x p o s e d r o c k outc r o p s - o f the ridge-.
There is
, ‘a sparse r e p r o d u c t i o n o f Douglas, fir' and.'Iodgepole pine,, an d the -Tegeta- '
- t i o n . a p p e a r s -faifly.stable.
Since t h e " r i d g e is in an e x p o s e d position,-
. the '-westerly'winds •.have •p r o b a b l y prevented, the 'establishment -of a ■sprube-'
f i r forest on'this area,.
The conifers f o r m a ,75^80%- c a n o p y,cover'with
'w h e a t g r a s s and fesoue grass: b e i n g f o u n d in.the open -spaces, , Snowberry
and ."creeping-.-juniper- (Juniperus "h e r i zont aid s')- are sc a t t e r e d ’ throughout the trapping- .site-but -only c o n t r i b u t e t o - 10% or less o f ' t h e - g r o u n d .cover,-
.
' Goat ■M o u n t a i n ;. Three and -one-half miles' west o f t h e Roes Creek b r i d g e - o n
- the Going-to-rthe-Sun highway, is the' Goat .Mountain site- (-Fig.. I ) ;
This
. ,site is o n p,- r o c k y .ridge .extending, a -few^ h u n h n e d -yards fr o m the -highway
to'the- .base -of. the- .cliffs of. the- mountain. (Fig,, .5-).
■covered w i t h a,, f e w v e r y old,deadfalls.-
The- l o w e r 1 slope is . -
The- u pper s l o p e - i s ' c o v e r e d w i t h
’
■bluebunch. f e s c u e ,.. bluebunch. wheatgr-ass,. Montana, p o l e m o n i u m (P o l e m o n i u m
-parvifOlium-) ' -serviceberry ./-buffaloberry and .-shrubby cinqu e f o i l w h i c h •
constitutes, about a. 50%. g round cover. ■..The,.rest of the g r o u n d is- c o m p rised
of rocks, and rock outcrop's, . The- area, h a s 1 a pparently .remained ,unchanged
i n i-recent ,years.
- «15*'BariQg- -C r e e k : l
Bhe- -trapping, site-,is located' I . U miles, we s t of B a ring .Greek(•Big, ,1)- -and extends on b o t h sides- of t h e highway, . The forest is- a m a t u r e
serai- stage forest and Douglas fir- and T o d g e p o l e -pine are the. dominant
conifers w i t h E n g e l m a n n spruce and a l p i n e 'f i r b e i n g f o u n d only as the
y o u n g g rowth (Fig, 6). . There are numerous- deadfalls, t h r o u g h o u t the area.
R o c k y M o u n t a i n m a p l e , -cowparsnip and .western--thimblebefry are,very dense
throughout- -the area and contribute to th e heavy- g r ound cover,in -most
places.
- 16-
Fig, 6
Serai stage Douglas fir forest at
Baring Creek site
Results
■ M o r p h o l o g i c a l .Variation
The m e a n measurements for t a i l length, hind foot length, ear length
.and greatest length
significantly larger
of
the skull (T A BLES I and I I ) are all highly
(P < 0 „01) for P= m,
(TABLES III, IV and V )«
arternesiae t h a n for P. m, osgoodi
Means of b o d y lengths are not nece s s a r i l y
c orrelated w i t h s u b s p e c i e s ; h o w e v e r , P_0 m.
The longer skull of ]?. m,
art erne siae is g e n erally larger.
art erne siae is most apparent in the snout, the
nasal bones a ccounting for 6l% of the i n c r eased l e n g t h ,
skulls of.individual P_, m,
increases in width,
cant differences
arternesiae are larger, t h e r e are only slight
as measure m e n t s for m a s t o i d b r e a d t h show.
nasal lengths of P. m,
t h a n those of P. m,
Al t h o u g h the
The me a n
arternesiae are all h i g h l y sig n i f i c a n t l y larger
osgoodi w i t h three exceptions w h i c h exhibit sign i f i ­
(P<0,05)
(TABLE V ) .
A separation of populations b y subspecies cannot be made in all
cases b y using b o d y l ength or m a s t o i d breadth.
Populations' of P. m.
arternesiae at the Narrows and Goat M o u n t a i n are signifi c a n t l y or high l y
significantly larger in b o t h mea s u r e m e n t s th a n all P. m.
tions w i t h only one exception.
osgoodi p o p u l a ­
There are no significant differences in
means of b o d y l e ngth b e t w e e n the Narr o w s p opulation a nd t he Babb p o p u l a ­
tion (TABLE VI),
The populat i o n of ]?. m.
arternesiae at Ap p e k u n n y Creek
has a significantly larger me a n b o d y l e n g t h th a n the P. m.
osgoodi from
St. M a r y Lake.
No other significant differences in b o d y l e ngth occur
among the P_. m.
a r t einesiae and P. m. osgoodi p o p u l a t i o n s ,
'While there
are sdme significant differences in m e a n m a s t o i d b r e a d t h b e t w e e n the tw o
.TABLE.I.
■
Means and ranges o f "body, measurements, of: p o p u l a t i e n ..samples of
..P e remy sous, manic u l a t u s qsgoodi a nd Peromy s c u s ■m a n iculatus art ernes iae
________ _________ __ _________
Area
Duck. Lake
No. of
.; osgoodi .
measurements'.in :.mm......................
No.. of
art ernes iae. _
28
-
26
. BabL
Body
Ta i l
length. .... . . •.length.
. 22
95.5
(-89 - 1 0 1 )
6
. A p p e kunny Creek
12
St M a r y -Lake
92.7
(86-99)
■ 20
S t .Mary Like
16
, Narrows
97.7
• (93-109)
95.8
(86-101)
100.0
(94-105)
Goat Mtn.
, Baring- Creek .
-
lU
. 11
:
-1 6 .6
(15-18)
. Si.'I .
(71-92)
.
...20,9
(20 - 2 2 ) '
; 16.9
( l 6 -l8 )
&3.9
(77-91)
. 2 1 .0
(2 0 - 2 2 ) '
(17-19)
..
1 0 6 .1
. 2 2 .8
■ (94-119)
■£22-2-3)
81.3
- (78-89)
101.3
(91-110)
2 0 .8
. 17,4
. 1 8 .8
.- ( 1 9 - 2 0 )
1 7 .6
( 1 9 - 2 2 ) : , ( 1 6 - 1 8 .5 )
2 2 .3
• •( 21 -2 3 )
10'5.0
.. 2 2 .6
(96-117)
. ( 2 1 -2 3 )
(9.4-117).
. 102.9
■ (96-110)
■ 2 2 .6 '
(21-24)
94.8
(9 1 - 1 0 8 )
102.8
. (93-112)
-22.,5 .
■ (:21-24)
101.6
Ear
length
- . 2 0 .6 '
( 1 9 -2 2 )
(60^85)
• - 9-7.0
(89-107)
- -Windy .Creek -
7 6 .6
• 96.4
. (91-105)
.
. H i n d foot
.-..length
.18,8 •
(18-20)
. 19.8
(19-21)
. 20.9 '
.(18-20)
■18.9
' (1 8 - 2 0 )
TABLE- II.
.Means and ranges -of skull mea s u r e m e n t s of- p o p u l a t i o n s a m p l e s
..Peromyscus m a n i c u l a t u s .osgpodi a nd P eroymscus .maniculatus- artemesiae
'
Area
B u c k Lake
Babb
Windy Creek
_
_
No.. of
osgoodi
No. of
' artemesiae
.
___
'''
Greatest, l e n g t h
of the skull,
Nasal
_. leng t h
25 .'7^
(24..75-26.93)
10.45
. (9.99-ll.H)
■10.55
(10.40-11.35)
. '26
26.09
(25.07-26.52)
10.60
.(9.6.9-11.55)
, 11.09
:(10.58-11.68)
.20
- 25.73
(25.-02-26.55)
. 10.42
. (9.06-11,71)
11.02
(10,75-11.27)
26.84
(26 ."02-28.0 5)
• 11,22
11.25
.(10.70-11.74),, >(11.00-11.64)
26
6
Appekunny Creek
St .Mary.Lake
_ m [ e a surementsin.mm (+ 0 .0 5 mm)
25.64
12
(24.68-27.72)
S t .Mary Lake
22
Narrows
16
2.6.40
(-24 *80-27,95)
27.06
9.95
_
M a s t o i d ...
Breadth'.
10.96
- 49.00-10.72) , (10,68-11.25)
, 10.90
(10,05-11,74)
, 11.17
.11.13
(io.-55-n.64)
11.32
(25.51 t 27.-75) '(10.43-11,75) . .(10.81-11,88)
Goat .Mtn.
.Baring Creek
15
ll
26.94
(25.54-27.90)
„10.77
11.27
.(10,04-11.43) -.(10,78-11.77)
26.55
(25.65-27.70)
- 11.14
H.17
,(10.50-11.68) '>(10.98-11.40)
—20—
T A B L E III.
Results of the modified D u n c a n new multiple range test
showing significant diff e r e n c e s between p o p u l a t i o n sample
means of tail lengths and hind foot lengths.
P. m. osgoodi
P. m. artem e s i a e
Jd
0)
O
jd
0)
0)
jd
O
A
A
P. m. osgoodi
A
D u c k Lake
t
I
I
CO
P
CO
W i n d y Creek
•H
5=
T
M
St. M a r y Lake
F
F
F
F
Narrows
F
F
F
F
Goat M t n .
F
F
F
F
si
Baring C reek
F
F
F
F
A p p e k u n n y Creek
F
F
F
F
d
6
hO
S
a
I
P
CO
•H
CO
ES
5
S
<
T
T
T
"~t "
T
T
T
T
T
T
T
T
T
T
T
T
T
T
T
t
St. M a r y lake
PmI
g
C
artemesiae
I
a
6
CQ
U
By
Babb
I
TD
a
a
_S
■
Hi n d Foot length
T , t -Ta i l length
Fff-Hind Foot length
C a p i t a l letter - h i g h l y s i g n i f i c a n t l y different (P<0.0l)
Lower case l e t t e r - s i g n i f i c a n t l y different (P<0.05)
B l a nk-no significant differences
T a i l length
-M
0)
0)
6
>>
-21T A B L E IV.
Results of the modified D u n c a n new mu l t i p l e range test
showing significant d i f ferences between p o p u l a t i o n sample
means of ear length.
P. m. osgoodi
P. m. artem e s i a e
Jd
D u c k Lake
Babb
W i n d y Creek
St. M a r y Lake
Ear length
a rtemesiae
P. m. osgoodi
0)
St. M a r y Lake
Narrows
Goat M t n .
B a ring Creek
A p p e k u n n y Creek
E,e-E a r length
Notations are the same as listed in TABLE III.
-22TABLE V.
Results of the modified D u n c a n new multiple range test
showing significant diffe r e n c e s between p o p u l a t i o n sample
means of the greate s t length of the skull and n a s a l length.
P. m.
P. m. a rtemesiae
osgoodi
CD
CD
3d
OJ
3
•H
rU
O
O
SC
CO
O
SI
PMl
Xl
Xl
5
>>
rU
C
-H
S
Babb
N
N
6
SO
-P
^5
~S~
I
•H
S
S
S
S
S
S
S
S
S
S
S
S
S
S
-P
-P
CQ
CO
S
W i n d y Creek
St. M a r y Lake
CJ
CO
g
S
Duck Lake
-P
>a
I
N
S
>)
d
CD
CD
a
a
OJ
jd
u
3d
S
S
I0)
CJ
Oj
S
S
S
S
CD
cd
St. M a r y Lake
-H
CO
S
BI
PhI
n
N
N
5
SO
d
0
S
S
S
S
-P
CO
Narrows
N
N
N
N
0 0
n
CD
-P
S
Cd
CD
-P
%
N
CD
5
Oh
O
CD
Goat M t n .
N
n
n
N
B a ring C r e e k
N
N
N
N
A p p e k u n n y Creek
N
N I N
N
S
S
Si
n
N a s a l length
S^s-G r e a t e s t length of the skull
N , n - N a s a l length
Notations are the same as listed in TABLE III.
U
-23Results of the modified D u n c a n new mul t i p l e range test
showing significant d i f ferences between p o p u l a t i o n sample
means of body length and mast o i d breadth.
P. m.
osgoodi
-M
Q)
<D
S
.a
-Q
§i
%
artemeslae
P. m. osgoodi
A
BI
Duck Lake
£
C
•H
P. m. a rtemesiae
a
I
CO
b
b
f§EU
Babb
b
W i n d y Creek
St. M a r y Lake
B
B
B
B
B
■im
H
b
St. M a r y Lake
m
Narrows
M
M
M
M
Goat M t n .
M
m
M
M
Baring Creek
m
A p p e k u n n y Creek
m
ffl
—
Al
m
B
1
m
M a s t o i d breadth
B , b - B o d y length
M , m - M a s t o d i breadth
Notations are the same as listed in TABLE III
b
B
B
B
Sy
B o d y length
TABLE VI.
-2 4 subspecies , there are no significant differences between seven combina­
tions of Po m. artemesiae and P_, m, osgoodi populations.
Although the intersubspecific differences in morphological measure­
ments are generally greater than within each subspecies, some significant
intrasubspecific differences also exist.
The mean tail length of the
Po m. osgoodi Duck Lake population is significantly smaller than the
means of the St. Mary Lake and Babb populations.
In addition the mean
tail length of the Duck Lake population is highly significantly smaller
than the mean of the P. m. osgoodi from Windy Creek (TABLE III).
The
Windy Creek9 Babb and St. Mary Lake populations are not significantly
different with respect to mean tail lengths.
No significant differences
in tail length occur among the P. m. artemesiae populations.
There is only slight intrasubspecific variation in hind foot length
(TABLE III),
The only significant difference found among either P. m.
artemesiae or P, m. osgoodi populations is that the P, m. osgoodi from
Windy Creek have a significantly larger mean for hind feet than the P. m.
osgoodi from Duck Lake,
The P, m. osgoodi population from Duck Lake has a significantly
shorter mean ear length than the P_. m, osgoodi from Windy Creek and St.
Mary Lake (TABLE IV").
cant differences.
ear length.
No other P, m, osgoodi populations show signifi­
The Pi, m. artemesiae populations vary considerably in
Although there are no significant differences in means among
the deer mice from St. Mary
Lake
,Baring
Creek and Appekunny Creek, all
other FL m. artemesiae populations show highly significantly differences
-25in means«
The greatest length of the skull measurements vary, and several
highly significant differences occur among subspecific populations
(TABLE V").
The Babb population of P. m. osgoodi has a highly signifi­
cantly smaller mean skull length than all of the other P_. m, osgoodi
populations.
The P, m, arternesiae populations from St, Mary Lake and
Baring pf'eek have significantly or highly significantly smaller mean
skull ■lengths than all other P_, m-, artemesiae populations.
The nasal measurement's do not vary as much within a subspecies as
the skull lengths.
The mean nasal length of P, m, osgoodi from St. Mary ■
Lake which is highly significantly smaller than those of all other P, m.
osgoodi populations is the only difference among ]?. m. osgoodi nopulations,
The mean length of nasals of Pi. m. artemesiae from the Narrows-
are significantly shorter than means of the P. m. artemesiae from the ■
Goat Mountain and Appekunny Creek.
Means of body sizes do exhibit some intrasubspecific variation
(TABLE V I ), -The P. m, osgoodi from St. 'Mary Lake have a significantly
shorter mean than those of deer mice frbm Buck Lake and -Babb.- The jP. m,
artemesiae from Baring Creek have a hi^lly. significantly shorter mean
■body length than the. Pi. m, artemesiae from the Narrows and Goat Mountain,Similarly the mean for P_. m. artemesiae from St. Mary Lake is signifi­
cantly and highly significantly shorter.than the means for deer mice from
the. Narrows and Goat Mountain respectively.
The only significant intrasu^specific difference for mastoid breadth
■- 2 6 occurs b e t w e e n the narrower, skull -w i d t h of the P. m.
a'rtemesiae fr o m St.
M a r y Lake and th'e deer mice f r o m the Narrows.
Comparisons made b etween . t w o m e a n s of.different mea s u r e m e n t s w i t h i n
o n e ■subspecies cannot necess a r i l y be m a d e w i t h i n the other'subspecies.
If the P» m.
osgoodi populations are r a n k e d w i t h respect to increasing
means .for b o d y l e n g t h the same r a n k i n g is not obt a i n e d for any other
external measurements taken.
The. P. m.
art erne’s ale p o pulations
show the -
s a m e .r a n king for means of tai l lengths a nd foot lengths but not for m eans
of b o d y l e ngth and ear length.
Means of skull m e asureme n t s exhibit more consistent ranking, but
these measur e m e n t s serve to show that the comparisons m a d e for one
subspecies C a n n o t 1always be ma d e for t he other-.subspecies,
of P. m.
artemesi.de exhibit the same rank i n g . f o r g reatest length of the
skull a n d m a s t o i d b r e a d t h but not for n a s a l length.
P'. m.
Populations
On t he other h a n d ,
os^oodi populations have the same ranking- for t he greatest l e ngth
of the skull and n a s a l length but not for m a s t o i d breadth.
Nine individuals w h i c h m a y indicate h y b r i d i z a t i o n b e t w e e n the two
subspecies were collected (TABLE V I I ),
Some, but not all, m o r p h o l o g i c a l
measurements of each suspected h y b r i d d o u s e are inte r m e d i a t e wi t h respect
to means of the two subspecies.
■
. 2 7 T
■'TABLE ■VII». ..Selected i^ody'and s k ull'measurements of su s p e c t e d hybrids
-' m e a s u r e m e n t .in m m .(+0 ,;0 5 :mm-, for' ,skull m e asurements)
■A r e a .
.- Tail
'H i n d
■ Foot
Greatest l e ngth
o f the skull.
'Ear
..
BaLb
.■■I. .
2. ■
m e an: .for' Babb
p o p u l a t i o n K.eisgbbdi )■ '
21
- 9.2
\ g o ; , 22
.
S t . iM e r y 'Lake '
3.
k.
.
5.
"mean.' for .St. --.Mary Lak;'e ■
■population '(psgoodi) '
mean.' for' St.',Mary LAke
'population .('arterneA i a e )"
’
-
,.Wasal--
--
18
2 6 .k 6
:-1 8 .
25,77
' 1 0 .k7
1 0 . k5.
- 1 0 ,6 0
8 1 .1 '
2 0 .8 .
16.7
2 6 .0 9
91 :
9k
89
'
2 1 .5 - - 19
22
18.5
22.
■ 18 ■
, 2 k ..80
■2 .
5 .7 k
1.
-
" 10,17
26;35
1 1 .1 1 '
: 1 0 .2 0
'
,81.3
-•2 0 .8
' 1 7 ,6
2 5 .6 k
9,95
'101,3.
■ 22.3
18 .,8
. 2 6 .1 0
-■ 10.90
, 2 6 ,2 2
26 ..07 '
■ -10, 30.;
,io.;85.'
W i n d y Creek'-
.-J6.,
- 91 ' ■ '2 1
91 ' ' !21
'■7.
-'mean- f o r W i n d y Creek
p o p u l a t i o n ■( os-goodi)
A p p e k u n n y Creek
■;
■ 8 .
mean.- for A p p e k U n n y Creek
■population -(artemesiae) ■
-
, 19
• 17
'
83.9
• '2 1 '
9k "
■ 23 '
106. 2
.22 i 8
- 1 8 .8
'21 .:..
.
18.
,
..
, '
1 7 .k
- 25 .'73
18
1 0 .ko
.
■ , 2 6 .0 2 •
■
-
1 0 .7 0
2 6 ,8 k
■
1 1 .2 7
BariRg^Creek
.■'."9..'
'mpan ■for ,'-all ■ o s g o o d i " .
,mean- ifor' .all1'art Seme's,iae -
93
.
'mean 'for .,-Baring Creek
popula t i o n • 't artelnesiae)
.
1 0 2 .8
8 0 .k
'
-
103.1
■<
'22.5
-
2 0 .8
■■
-2 2 .5
1 8 ,9
.
-
.
'
,,
-
;
25/83
'26.77
.1 0 .6 9
1 1 .1 k
.26.55
17
1 9 ,2
25.65
10 A s -
I
11.00
-
-28Ecological Distribution
The two subspecies are r e p r e s e n t e d b y a p p r o x i m a t e l y equal p o p u l a t i o n
densities in the favorable h a b i t a t s ..
T he subspecies arternesIae was
t r a p p e d - w i t h a 7«0% success as opposed- to a 7.2% success for the sub­
species osgoodi
(TABLE V I I I ).
The aliopatric areas include D u c k L a k e , Babb and W i n d y Creek, for
P. m. o s g p o d i , on the n o r t h and e a s t , and the N a r r o w s , Goat- Mo u n t a i n a nd ,
B a r i n g Creek, for P. m.
area.
a r t e m e s i a e , on t he south and west of the study
■ The sympatric. area lies along t he f o r e s t - g r o v e l a n d ecotone
including the west shore of St.. M a r y Lake and ■A p p e k u n n y C r e e k 'in the
Swiftcurrent d r a i n a g e .
In the aliopatric area P. m. osgoodi was t r a p p e d on prairie g r a s s ­
l a n d and in disturbed aspen groveland.
sites was b etter in d i s t urbed -areas
surrounding prairie,
P» m.
Trapping, success in the prai r i e
(rqad b e d and g r a v e l pit) than in the
,In the d i s t u r b e d aspen g r o v e l a n d at W i n d y Creek
osgoodi was .trapped n e a r s h r u b s , b r u s h p i l e s , rock piles and along
I
the edge of the dry r ocky s t r e a m •channels that cut t h r o u g h the area.
In the aliopatric area of P. m.
artemesiae mi c e w e r e t r a p p e d in a
m e a d o w at Goat M o u n t a i n and the Douglas f i r-lodgepole p i n e -forest at the
N a rrows a n d ,Baring' Creek.
At Goat M o u n t a i n and the N a r r o w s the p r e f e r r e d •
habitat of the mice appeared-to be rock pptcrops, and, in addition m i c e
'
'
'
I
at the Ifarrows were t r a p p e d near b r u s h p i l e s and juniper bushes around t he
'
clearings in the scattered Douglas fir forest.
-
Most o f the mice in the
m ature forest at B a r i n g Creek we r e caught along the dry r o c k y wa s h or
TABLE VIII,
Overall t r a p p i n g success for the two subspecies in each ar e a sampled.
totals include t hose m i c e u s e d for m o r p h o l o g i c a l measurements,
Allopatric
P. m,
osgoodi
Area
Duc k Lake
Babh
P. m.
artemesiae
Habitat
..'type
No,
.traps
1 .
prairie
road be d
prairie'
. gravel pit
100
525
The
No.
mice
Io
3
40
3.0
7,6
25
3
12.0
100
28
2 8 .0
10.1 '
W i n d y Creek
d i s turbed aspen grevelaind
575
58
Narrows
stable.Douglas fir-
575
4o
7.0
Goat M t n ,
meadow
350
40
11.4
Bari n g Creek
Douglas fir forest
225
24
10,7
■
i
I
TABLE VIII.-
SympatriC
(continued) O v e r a l l t r a p p i n g success for the ^ w o suhspetiies in ea,ch' area
sampled.
The totals include those mice u s e d for m o r p h o l o g i c a l measurements.
Ar e a
Hahitat
type
Appek u n n y Creek
No,
'
"" ,traps
.
■-koe
d i s t u r b e d aspen g r o veland
• 100
aspen groves
' 26 a r t .
I osg.
%
6 .8
- 0 .0
. - 0
75
I osg-.
■ 1 .3
meadows
250
8 osg..
3 .2
aspen groves
200
I osg.
0 .5
■Douglas fir forest
S t . M a r y Lake
No,
'
,mice- . ..
■ 225
meadows
Douglas fir forest'
s c a t tered conifers
beach ■
-
.■
6 osg.
.8 .9
■ 275
9 art.
3.3
725
26 osg.
3 .6
75
7 -art.
5 osg..
1 6 .0
cB" H
T o t a l P . mi osgoodi .
: T o t a l P. m. arternes,Iae
"
• it a r t .
' 186
■155
■
7-2
-7.0
-3 1 near brushpiles and l o g s «
The areas of dense u n d e r g r o w t h a ppeared to be
avoided.
A l t h o u g h the sympatric zone is narrow,
found w i t h i n it.
a v a r i e t y of habitats are
At A p p e kunn y Creek, th e tr a p p i n g success was not as
h i g h as at W i n d y Creek.
Only one P. m.
osgoodi was t r a p p e d at this site
out of t w e n t y seven mice c a u g h t ,
A l l three m a j o r vegetati v e habitats of the study area are found at
the St o M a r y Lake s i t e .
P. m. osgoodi was t r a p p e d in the meadows or in
the sca ttered conifers n e a r the edges of meadows w h i l e the subspecies
arternesiae was found in the coniferous forest west of t h e aspen groves
land.
H o w e v e r , in m a n y places w h e r e t he u n d e r g r o w t h in t he coniferous
forest was dense no P,- m.
artemesiae we r e c a u g h t ,
B o t h subspecies were
concentrated in' rocky and dis t urbed a r e a s ’.
At A p p e k u n n y Creek and at two locations near St. M a r y Lake contact
b e t ween the two subspecies is d e f i n i t e l y made.
B o t h subspecies were
t r a p p e d along the eroded beaches of S t . M a r y Lake fr o m a point two and
one-qua rter miles from the outlet of the' lake southwest along the shore
for one and one-hdlf miles.
Also b o t h subspecies we r e c o l l ected from a
r o c k y , -grassy ridge w h i c h projects fr o m t he coniferous forest into the
most w e s t e r l y m e a d o w at St. M a r y Lake.
Of the n i n e i n t e r mediate mice
trapped, one was caught at Ap p e k u n n y Creek, one from t h e b e a c h at St.
M a r y Lake,
and t w o ‘from a dum p g r o u n d at the edge of the Douglas fir
forest near the- rocky ridge w here b o t h subspecies were trapped.other, m i c e caught in the dumpgr o u n d w e r e P. m.' a r t e m e s i a e .
Three
-3 2 The intermediate types c o l l e c t e d at Babb end W i n d y Creek were
t r a p p e d in areas w here P_. m.
art erne siae was not found.-
t r a p p i n g sites possi b l e habitat for P,
However
f
artemesiae is n e a r by.
at b o t h At B a b b 1
the banks of the S t M a r y Riyer and L o w e r St. M a r y Lake and the coniferous
forest at W i n d y Creek provide the suitable habitat.
On t h e other hand,
the intermediate f o r m caught at t he B a r i n g Creek site was t r a p p e d several
miles from the nearest k n o w n suitable habitat of P. m,
osgoodi,
Discussion
One of the best s t u d i e d and most w i d e l y d i s t r i b u t e d species of '
P e r o m y s cus is P_, m a n i c u l a t u s , w h i c h is d i s tributed over most of N o r t h
A m e r i c a except for the states of the southeast a nd t he far arctic r e g i o n s .
Hall and K elson
(1959) descri b e d this species as c o n s i s t i n g of a long
series of i n tergrading p o p u l a t i o n s .
In some c a s e s , subspecies w i t h
adjoining geographic ranges do not intergrade ...directly, b ut the o r e t i c a l l y
intergrade c i rcuitously t h r o u g h other s u b s p e c i e s .
The deer mice in the study area can be separated into two distinct
m o r p h o l o g i c a l types w h i c h supports th e current classi f i c a t i o n of mi c e in
that area.
The means of tail length, h i n d foot length,
ear length,
greatest l ength of the skull and n a s a l l e ngth are all s i gnificantly or
h ighly significantly larger for
P.
m,
aftemesiae th a n for
P_.
m, o s g o o d i .
The m e asurements for t a i l length a nd ear length e x h i b i t e d little o v e r ­
lap in range, and t h e y are the most r e liable m o r p h o l o g i c a l criteria for
distinguishing b e t w e e n subspecies.
generally longer t h a n those of
difficult to distinguish.
P_.
The h i n d feet of
m.
P.
m.
arternesiae are
osgoodi but the difference is often
It is p o s s i b l e to separate t he skulls of P. m.
arternesiae f r o m t hose of P. m.
osgoodi y i t h reasonable a c curacy without
m e a s u r i n g t h e m although the m e a n diffe r e n c e in greatest l e n g t h of the
skull is less t h a n 2 mm.
h ighly significant..
larger t h a n
istic.
P.
A l t h o u g h the m e a n difference is small, it is
The body l e ngth of P, m. art erne s i a e , while averaging
m. o s g o o d i , cannot be u s e d as a good d iagnostic ch a r a c t e r ­
The m e a n difference in b o d y size is small and some populations of
P. m< osgoodi have l arger b o d y size m e a s u r e m e n t s th a n some of the P. m,
artemesiae populations.-
Similarly, m a s t o i d ' b r e a d t h cannot be reliably'
u s e d to •d istinguish b e t w e e n subspecies. ■ Also Pi. m.
general a darker pelage than. P. m. o s g o o d i .
a rtemesiae has in.
However-, this characteristic
was not u s e d since'pelage c o l o r .reflects the climatic belts of the area
and. the color of the surface soils -( D i c e ,■1939)«
The longer tails and h i n d feet of Pi. m.
artemesiae are pr o b a b l y an
adaptation.to.their, semiaboreal l i f e . i n the. V o o d l a n d habitat .(Horner,'. '
1954)6
On the o t h e r ■hand,, the shorter tails and h i n d feet o f ’Pi m»
'
osgoodi p r o b a b l y r e f l e c t - t h e ,cursorial life in a p r a i r i e .h a b i t a t ,. Dice .
(1944)
states-, -however, that t h e r e - i s - n o evidence to prove- t h a t tail. .
l e ngth or ear- size-is actually an i m p o r t a n t .factor in t h e . s u r v i v a l ofeither form.
'
The change in morphological- v a r i a t i o n is.abrupt in t he study area.
Populations and most individuals of different- sub,species adjacent to the
sympatric z o n e . are-easily dis t i n g u i s h e d b y m o r p h o l o g i c a l features such
as t a i l . l e n g t h and. ear l e n g t h T h e
-
abruptness-of, the m o r p h o l o g i c a l
v a r i a t i o n is r e lated t o - the.n a r r o w n e s s of the sympatric zone.which is
l i mited t o ■'the. f o r e s t - g r o v e l a n d .ecotone a n d .m a y be due to the lack, of
s i g n i ficant'hybridization in that n a r r o w zone.
-There is a n 'apparent,'cline-
of m o r p h o l o g i c a l m e a s u r e m e n t s .of ea c h subspecies on .either side of the
sympatric zone..
This.is-par t i c u l a r l y n oticeable w h e n t a i l lengths.are
u s e d as.an example
(Fig,
J ),
There: appears, to b e ■little h y b r i d i z a t i o n across t he -sympatric zone. '
-Only nine individuals t r a p p e d in the study area w e r e of intermediate.-
P. m. artemesiae
85Tail
length
P. m. osgoodi
(mm) 75-
sympatric zone
West
Fig.
7
Distance in miles (not to scale)
Geographic variation in means of tail lengths of P. maniculatus across Montana
S M L , St. M a r y L a k e ; AC, A p p e k u n n y Creek; N, Narrows: CM, Goat Mtn.;
B C , Baring Creek; W C , W i n d y Creek; B, Babb; D L , D u c k Lake
P, Poison, Montana; A v C , Av a l a n c h e Creek, Glacier N a t i o n a l Park;
L, L e w i s t o w n , Montana; MG, Miles City, M o n t a n a
Fr o m Dice, 1944.
East
-3 6 size in some measurements
subspecies was tentative.
(TABLE V I I ), and. assignment to a particular
These nine mi c e m a y be hybrids or may
represent, extreme- variants w i t h i n the populations,
'!Eight of the mice
-
were caught in areas where contact b e t w e e n the two Subspecies either was
obser v e d or was possible.
The m o u s e t r a p p e d at B a r i n g Creek, however,
was t r a p p e d well outside the r e c o g n i z e d sympatric area.
Intrasubspecific variati o n exists among populations,
a nd some
significant and h ighly significant differences do exist in some m e a s u r e ­
ments, ■ V a r i ation w o u l d be expected' as individual- characters, are seldom
u n i f o r m throughout the whole range of any species or subspecies, even in.
areas w i t h r elatively homogenous environments. (Dice, 19^0),'
In mammals variab i l i t y of m o r p h o l o g i c a l characters-is not due
p r i m ari ly to a direct influence of- the environment, but is b a s e d on
h e r e d i t a r y variations
(Dice, 19^0),
Blair. (1950)
states that a m ajor
factor in g e o g r a p h i c . d ifferen t i a t i o n of Peromyscus is the selection of
genotypes b y the e n v i r o n m e n t , . In regions of general e n vironmental
u n i f o r m i t y .differences among p o p ulations m a y be ex p e c t e d to-be small and
in regions of environmental diversity inte r p o p u l a t i o n - variation, is. likelyto be large.
The' habitat- found in the study area is var i a b l e and ma y
account, for some, of the v a ria b i l i t y between- and within, p o p u l a t i o n s ,.
A l t h o u g h P e r p m y s cus is w i d e l y distributed-in. N o r t h America,
they are
chiefly inhabitants of woodlands, brush l a n d s and p i o n e e r stages, of g r a s s ­
l a n d development
( B a k e r , .1968),
The large geographic range of -Peromyscus
maniculatus reflects the vari e t y of h a bitats to . w h i c h the species is
-
37
-
morphologically, behaviorally and physiologically adapted.
Although Po m. osgoodi is classified as a grassland form and P. m.
artemesiae as a woodland form, both subspecies were usually trapped in
or n^ar rock piles, brushpiles and fallen trees, often in early serai
stages o
Mice.of the subspecies artemesiae are not limited to forest
habitatsj.they were found in meadows within the forest zone where approiate cover exists.
Mice were not caught in areas of heavy ground cover
such as in the mature aspen .groves; in three hundred trap nights only
one mouse, a P, m, osgoodi was caught,
The allopatric P 1 m. osgoodi inhabitated two general habitats in the
study area, the grassland and the aspen groveland.
However, P. m. osgoodi
were caught in the scattered coniferous trees that were found adjacent to
the aspen groveland at Wild Creek.
The allopatric area for P. m.
artemesiae lies within the coniferous forest zone.
The sympatric area lies along the aspen groveland-coniferous forest
ecotone and includes the St. Mary Lake and Appekunny Creek sites.
The
area of overlap between the two subspecies is limited and is restricted
to a contact where the coniferous forest meets the meadow of the grove­
land.
Contact between the two subspecies occurs infrequently because of
separation of suitable grassland and forest habitats in many places by
bands of dense aspen groves or coniferous forests with dense undergrowth,
neither of which provide favorable habitat for the mice.
All three
specific areas of contact found between the subspecies are small.
ever,
St. Mary- Lake road cuts, stream and lake banks and dump-
How­
-3 8 greunds in the sympatric zone offer avenues of p o t e n t i a l contact betw e e n
subspecies.
Selection for a s p eciali z e d habitat in P 6 m a n I c u l atus does not seem
to be accounted, for b y a food differ e n c e
(bogshall, 1928; W i l l i a m s ,'1959)
or b y temper a t u r e selection '(Stinson and Fischer, 1963)«
Murie
(1 9 6 1 )
speculated that habitat selection m a y be r e l a t e d to p h y s i c a l structures
of the habitat and Harris
(1952) d e m o n s t r a t e d habitat selection in
h i g h l y a r t i f i cal labora t o r y e n v i r o n m e n t s „
Genetic a nd b e h a v i o r a l factors
are apparently involved in habitat selection
(W e c k e r , 1963).
Competition
m a y also be important in the d i s t r i b u t i o n of closely r e l a t e d species of
Peromyscus
(M c C a r l e y , 1 9 6 3 )»
■
For a circular overlap to exist the e n d-populations of a chain of
interbreeding populations must meet but fail to i n t e r b r e e d due to
isolating m e c h a n i s m s «.
In the study area the failure of i n tepbreeding m a y
be attributed ' l a r g e l y to the lack of contact b e t w e e n t he .two subspecies
due to
(l) somewhat different habitat r e q u i r e m e n t s , an d (2) to a b u f f e r
of h e a v y v e g e t a t i o n along the g r o v e l a nd-coniferous forest e cotone whererelat i v e l y few mice are found=
However,
contact is ma d e in some places,
and some possible evidence of l i m i t e d h y b r i d i z a t i o n was.found=
In areas
where s eparation of subspecies due to habitat prefe r e n c e s breaks down,
b e h a v i o r a l differences p r o b a b l y .contribute to r e p r o d u c t i v e isolation of
the two s u b s p e c i e s ,
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