Habitat Selection and Sexual Suggestion of Rocky Mountain

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1987

Habitat Selection and Sexual Suggestion of Rocky Mountain Habitat Selection and Sexual Suggestion of Rocky Mountain

Bighorn Sheep in Custer State Park, South Dakota Bighorn Sheep in Custer State Park, South Dakota

Larry J. Layne

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HABITAT SELECTION AND SEXUAL SEGREGATION OF ROCKY

MOUNTAIN BIGHORN SHEEP IN CUSTER STATE PARK, SOUTH DAKOTA

BY

LARRY J. LAYNE

A thesis submitted in partial fulfillment of the requirements for the degree

Master of Science Major in Wildlife and Fisheries Sciences

(Wildlife Option) South Dakota State University

1987

HABIT,�T SELECTIO�I A1\JD SEXUAL SEGREGATION OF ROCKY MOUNTAH:

BIGHORN SHEEP IN CUSTEq STATE PARK, SOUTH DAKOTA

This thesis is app:Jved as a cr2dit3ble and indep�ndent

investigation by th� candidate for the degree Master of Science,

and is acceptable for meeting the th8sis requir2ments for this

degree. Acceptance of this th2sis does not i�ply that the

conclusions re3ched by t�e candij�te are necessarily the

conclusions of the majcr depart�ent.

Thomas/R.Ac'cabe Thesis .:.\dvisor

Char 1 �s G. · �s·63f�t Head Dept. of �ildlife and Fisheries Sciences

JJate

t\CK.t.�OWLEDGEMENTS

I would especially like to thank Dr. T. R. McCabe

for 311 of his encouragement and assistance during this

study, and for his help i� analysis and intarpretation cf

the data.

I am grateful to W. Winter, R. Noem, a�d w. Jackson

for their help in the field and contir.ued support for the

study. Also, to �. Bland and G. Brundige for their halp

with vegetation measurements and to all the students who

provided assistance with trapping.

My thanks go to T. R. McCabe, C. G. Scalet, K. H.

Higgins, G. R. Larson, and R. M. Todd for editing the

manuscript. They provided many helpful ccmments and

insights.

I especially thank my grandmother, T. James, for

all the support and advice she has provided, for which

this degree would not have been possible.

Funding was provided by a grant from the Foundation

for North American Wild Sheep, Custer State Park, and

Federal Aid administered by South Dakota Department of

Game, Fish and Parks.

i i i

CONTENTS

ACKNOWLEDGEMENTS. .iii

CONTENTS . . . . . . . . . . . . • . • • . . . . . . . . . . . • . . . . . . . . . . . . . . . . . iv

LIST OF TABLES . ... . .v

LIST OF FIGURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii

ABSTRACT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix

INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

STUDY AREA .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . • 6

METHODS AND MATERIALS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

RESULTS . ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

DISCUSSION. . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . ' .34

MANAGEMENT RECOMMENDATIONS. . . . . . . . . . . . . . . . . . . . . . . . . .

LITERATURE CITED ... . . . .. . . .

. 46

48 . . . . . . . . . . . . . . . . . . . . . . . . . .

APPENDIX .. . . . . . .. . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

iv

LIST OF TABLES

Table 1. Number of vegetation sampling plots for each habitat type located within each sheep herd range in Custer State Park, SD, from August through September, 1985 ................... 19

Table 2. Discriminant analysis classification summary for each habitat type, for all sheep ranges included, in Custer State Park, SD, from August through September, 1985 ................... 19

Table 3. Proportion and area (ha) of each habitat type found within each bighorn sheep herd home range in Custer State Park, SD, 1985 ............. 25

Table 4. Selection and avoidance of habitat types by Rocky Mountain bighorn sheep herds in Custer State Park, SD, from July through October, 1985 ........................................ 25

Table 5. Selection and avoidance of habitat types by pooled ram and ewe bighorn sheep herds in Custer State Park, SD, from July through October, 1985 ........................................ 27

Table 6. Proportion (no. of observations) of behavior categories for bighorn ram and ewe sheep herds in Custer State Park, SD, from July through October, 1985 ............................... 27

Table 7. Relative frequency (no. observations) of resting activity by Rocky Mountain bighorn sheep herds in each habitat type in Custer State Park, SD, from July through October, 1985 ............. 28

Table 8. Relative frequency (no. observations) of feeding activity by Rocky Mountain bighorn sheep herds for each habitat type in Custer State Park, SD, from July through October, 1985 ... 30

Table 9. Mean distances (no. observations) [group size] between locations of foraging sheep and escape terrain for all bighorn sheep herds for each habitat type in Custer State Park, SD, from July through October, 1985 ....................... 30

v

Table 10. Selection and avoidance of habitat types used for feeding by Rocky Mountain bighorn sheep herds in Custer State Park, SD, from July through October, 1985 ...................... 31

Table 11. Selection and avoidance of habitat types used for resting by Rocky Mountain bighorn sheep herds in Custer State Park, SD, from July through October, 1985 ...................... 33

Table 12. Expected number of occurrences for each habitat type by Rocky Mountain bighorn sheep herds in Custer State Park, SD, from July through October, 1985 .............................. 39

Table Al. Occurrence of habitat occupation by the east end ewe herd in Custer State Park, SD, from July through October, 1985 ................ 52

Table A2. Occurrence of habitat occupation by the west end ewe herd in Custer State Park, SD, from July through October, 1985 •............... 52

Table A3. Occurrence of habitat occupation by the Grace Coolidge ewe herd in Custer State Park, SD, from July through October, 1985 ............ 53

Table A4. Occurrence of habitat occupation by the southeast ram herd in Custer State Park, SD, from July through October, 1985 ............ 53

Table AS. Occurrence of habitat occupation by the southwest ram herd in Custer State Park, SD, from July through October, 1985 ............ 54

Table A6. Occurrence of habitat occupation for pooled ewe herds in Custer State Park, SD, from July through October, 1985 ...................... 54

Table A7. Occurrence of habitat occupation for pooled ram herds in Custer State Park, SD, from July through October, 1985 ...................... 55

vi

LIST OF FIGURES

Figure 1. Map of ram and ewe home ranges from July through August in Custer State Park, South

Figure 2.

Figure 3.

Figure 4.

Figure 5.

Figure Al.

Figure A2.

Figure A3.

Figure A4.

Dakota, 1985 ................................ 7

Canonical representations of the first and second discriminant functions for habitat types in Custer State Park, SD, 1985. Canl uses vegetation variables grass, forb, duff, bare ground, and canopy coverage. Can2 uses vegetation variables forb, rock, canopy coverage, and duff ......................... 20

Mean(+ se) of ground cover, canopy cover, and horizontal density for all bighorn sheep ranges combined for each habitat type in Custer State Park, SD, 1985 ............................. 21

Mean(+ se) of tree basal area/ha for all bighorn sheep ranges combined for each habitat type in Custer State Park, SD, 1985 ........ 22

Mean(+ se) of number of tree stems/ha for all bighorn sheep ranges combined for each habitat type in Custer state Park, SD, 1985 ........ 23

Mean(+ se) of ground cover, canopy cover, and horizontal density for all bighorn sheep ranges for mixed grass/forb habitat type in Custer State Park, SD, 1985 ............... 56

Mean(+ se) of ground cover, canopy cover, and horizontal density for all bighorn sheep ranges for riparian habitat type in Custer State Park, SD, 1985 ...................... 57

Mean(+ se) of ground cover, canopy cover, and horizontal density for all bighorn sheep ranges for Ponderosa pine/no understory habitat type in Custer State Park, SD, 1985 ...................................... 58

Mean(+ se) of ground cover, canopy cover, and horizontal density for all bighorn sheep ranges for Ponderosa pine/grass forb habitat type in Custer State Park, SD, 1985 ....... 59

vii

Figure AS.

Figure A6.

Figure A7.

Figure A8.

Figure A9.

Figure AlO.

Figure All.

Figure A12.

Figure A13.

Figure Al4.

Mean (+ se) of ground cover, canopy cover, and horizontal density for all bighorn sheep ranges for steep rocky/ponderosa pine habitat type in Custer State Park, SD, 198 5 . . .. . . . 60

Mean(+ se) of ground cover, canopy cover, and horizontal density for all bighorn sheep ranges for steep rocky/grass forb habitat type in Custer State Park, SD, 198 5 . .. .. .. . . . . . 61

Mean (+ se) of tree basal area/ha for all bighorn sheep ranges for riparian habitat type in Custer State Park, SD, 198 5 . . . . . . . . . . . . 62

Mean (+ se) of tree basal area/ha for all bighorn sheep ranges for Ponderosa pine/no understory habitat type in Custer State Park, SD, 19 8 5 ...................... , •••..••••..• 6 3

Mean (+ se) of tree basal area/ha for all bighorn sheep ranges for Ponderosa pine/grass forb habitat type in Custer State Park, SD, 1985 ...................................... 64

Mean (+ se) of tree basal area/ha for all bighorn sheep ranges for steep rocky/ponderosa pine habitat type in Custer State Park, SD, 198 5 . . . . .. . . . . . . . . . . . . . . . 6 5

Mean (+ se) of nt.:.mber of tree stems/ha for all bighorn sheep ranges for riparian habitat type in Custer State Park, SD, 198 5 .. . . . . 66

Mean (+ se) of number of tree stems/ha for all bighorn sheep ranges for Ponderosa pine/no understory habitat type in Custer State Park, SD, 198 5 . . . . . . . . . . . . . . . . . . . . . 67

Mean (+ se) of number of tree stems/ha for all bighorn sheep ranges for Ponderosa pine/grass forb habitat type in Custer State Park, SD, 1985 . . .. . . . . . . . . .. . . . .. . . . . .. . . 68

Mean (+ se) of number of tree stems/ha for all bighorn sheep ranges for steep rocky/ponderosa pine habitat type in Custer State Park, SD, 198 5 . . . . . . . . . . . . . . . . . . . . . 69

vi i i

ABS'IRACT: One hypothesis which explains segregation between Rocky Mountain bighorn ram and ewe herds was examined using the Custer State Park bighorn sheep population. Three predictions of this hypothesis, similarity of habitat types, similarity of habitat utilization, and high home range fidelity, were assessed using physical habitat measurements and locations of radio-tagged individuals of both sexes. Habitat types were similar, as classified �ith discriminant analysis, with respect to each type, across all of �he sheep ranges. Members of each sheep herd maintained high fideli�y to their respective home range. Habitat utilization differences were inconsistent among the herds, regardless of sex, except for selection against doghair ponderosa pine habitat type by all herds. Utilization of feeding and resting areas were also selected or avoided inconsisten�ly, except for avoidance of doghair ponderosa pine for both resting and feeding, and also ponderosa pine/no understory for feeding. Mixed grass/forb, ponderosa pine/grass forb, and riparian habitat types were used most frequently for feeding, and steep rocky/ponderoasa pine most frequently for resting. Rams foraged at significantly greater distances {F = 4.99, p = 0. 0009) from escape terrain than ewes although group size of rams was always small (1-5 individuals) and ewe group sizes ranged from small to large (up to 29 members) . These results supported 2 of the 3 hypothesis predictions; similarity of habitat types and fidelity of home range. However, the most important prediction, similarity of habitat utilization between the sexes, was not supported and consequently the hypothesis of mi�imizing habitat competition between the sexes was rejected as not providing a complete explanation for sexual segregation. An alt:rnative hypothesis, where rams and ewes segregate in order to reduce agonistic interactions between them, is presented. Future directions to more completely test the competing �ypotheses which explain sexual segregation in bighorn sheep are suggested.

ix

INTRODUCTION

Spatial segregation between Rocky Mountain bighorn

sheep (Ovis canadensis canadensis) ram and ewe herds has

been documented by Geist (197 1), Geist and Petocz (1977),

Shank (1979), Morgantini and Hudson (1981), and Hogg

(1983), where ram herds consist of mature males

approximately 4 years old and older and ewe herds are

comprised of all other individuals. Geist ( 197 1), Shank

(1979), and Hogg (1983) have shown that segregation

occurs year-round except during the breeding season

(November and December) when the sexes congregate on a

traditional breeding range (cf. Geist 1971, p 209).

These studies also have shown that the sexes remain

separated during the winter, when segregation should be

least likely. During winter, resources, particularly

forage, are most limiting and when the sexes would be

expected to remain congregated after the breeding season,

such as at available foraging sites. However, both Geist

and Petocz (1977) and Morgantini and Hudson (1981)

reported that the sexes remained segregated on a

continuous winter range, even during severe winters.

Four hypotheses have been developed to explain

sexual segregation of bighorn sheep. Shank (1979)

...

2

believed sexual segregation was a result of differential

habitat requirements due to sexual dimorphism.

Segregation has been suggested as an anti-predator

strategy for males which are physically weakened after

the breeding season (Geist and Bromely 1978). Morgantini

and Hudson (198 1) suggested that sexual segregation

reduces frequency of agonistic interactions among rams

during the post-breeding season and maximizes fitness of

rams by conserving energy when reproduction is not

possible. Geist and Petocz (1977) explained segregation

as a mechanism for rams to minimize habitat competition

with pregnant ewes and their prospective lambs, thus

increasing survival of lambs, and thereby maximizing

reproductive fitness of rams.

Morgantini and Hudson {198 1) concluded that

reduction of agonistic behavior among rams after the

breeding season provided the best explanation for sexual

segregation during winter, and each of the other

hypotheses could be considered additional benefits

accrued as a result of this behavior. However, this

hypothesis is inadequate to explain why segregation is

maintained during the rest of the year when energy intake

is maximum and behaviors among rams would be least

detrimental. The hypothesis of increased predation risk

proposed by Geist and Bromely (1978) is also inadequate

to explain maintenance of segregation between the sexes

during the sWTU11er and fall when body condition of the

sexes should be in best condition. The hypothesis by

Shank (1979) adequately explained why segregation may be

maintained throughout the year, but because differential

habitat requirements were not demonstrated, he concluded

that the sexes did not partition their range in a manner

that best satisfied sex-specific requirements . Only the

hypothesis of Geist and Petocz {1977) of minimizing

habitat competition between the rams and ewes best

explains why segregation should be maintained throughout

the year, except during the breeding season .

3

Geist and Petocz (1977) emphasized reduced

competition for forage resources, however habitat

provides other resources, some of which may be competed

for (Anderson and Shugart 1974). Habitat is defined

primarily as a place where an organism lives and

secondarily as how that place is characterized

(Wittenberg 1981, Ricklefs 1973, Brown and Gipson 1983).

Bighorn sheep habitat may be divided into a physical

component and a forage component, with the forage

component described by the composition of forage species

(eg. grasses and forbs), and the relative importance each

contributes to the diet, and the physical component,

which consists of both biotic and abiotic descriptors and

their spatial distributions; in essence, the visual

appearance of the habitat. It is unknown whether

intersexual competition for the structual component or

the forage component is more important in bighorn sheep.

However, Shannon et al. (1975), Morgantini and Hudson

(1981), Geist (1971), and Geist and Petocz (1977) showed

that habitat structure was important in explaining the

distribution of ram and ewe herds, and Geist {1974)

considered the 3-dimensional structure of habitat to be

an important factor in ungulate social evolution.

The objective of this study was to examine the

predictions of the hypothesis that segregation reduces

habitat competition between ram and ewe herds in bighorn

sheep during the summer and fall. The predictions were,

if rams and ewes segregate in order to reduce habitat

competition between them, then they should: 1) occupy

home ranges which share similar physical characteristics

for each habitat type, 2) utilize those types with

similar frequencies, and 3) maintain fidelity of home

range occupation both spatially and temporally. In this

study, habitat characterization focused on the physical

component.

4

The bighorn sheep population found in Custer State

Park (CSP) is particularly well suited to examining this

hypothesis. The present population is derived from 22

5

individuals (15 ewes, 7 rams) transplanted from Wyoming

in 1964 (W. Jackson unpubl. rep. 1981) . Between 1964 and

1985, the herd increased to a level of at least 90

animals and separated into 6 distinct herds. Because the

currently occupied areas were vacant of bighorn sheep at

the time of the transplant, an assumption was made that

these separate herds have established their home ranges

to best satisfy each herd's habitat choice. Given that

the sheep had free choice to establish a home range

anywhere within the park boundaries, their observed home

ranges should reflect what they considered as the optimal

areas to define a home range. Additionally, the ranges

of all herds are assumed to be qualitatively equivalent,

where at least the minimum amount of nutrition is

available to all members of this bighorn sheep

population.

6

STUDY AREA

Research was conducted in CSP, which is located in

the southeast portion of the Black Hills, South Dakota.

Bighorn sheep ewes primarily inhabit French Creek Canyon,

located in the central portion of the Park, and rams

occupy ranges peripheral to those of the ewes (Fig. 1) .

French Creek Canyon is approximately 19 km long and

ranges from 70 to 140 m in depth. It is characterized by

steep, rugged walls with adjacent rolling meadows and

ponderosa pine (Pinus ponderosa) forests. The Park

headquarters region, located in the center of the Park,

contains a few meadows and steep, forested hills with

rock outcrops. The southwestern portion of the Park is

characterized by hilly, forested terrain with some

extensive rock outcrops adjacent to a few relatively

large meadows. The southeastern portion of the Park

south of and adjacent to French Creek Canyon is

characterized by less steeply rolling, but forested,

terrain with few rock outcrops and few meadow areas.

Physiographically, the headquarters region and southwest

area appear similar, while the southeast area is the

least rugged of any of the areas used by CSP bighorn

sheep. Elevations within CSP bighorn sheep ranges vary

from 1160 to 1707 m, rising steadily from the southeast

to the north and west.

•

.--..,...;. c::::

f i��-e Loca�ic� of Fre�cn Cre��. Ca�ycn ano �am ano ewe grc�:: ��! rancei iG Cus:er Stace Far�. SoJtn oa�oca. 1985. E-..e gr:::o.:c!: _{ZZj Grace Ccc l i o·;:i=. � E.:1sc Enc a:-.c Gra:::e Ccci ,·:::;;:::!. �we�-:: [r,c. F.a,., g:-o·J::'3: illScuc:-,eia�:.� Sc..w:�, .. ec:. �cc::le: 0--1 m;iec.

7

8

l\'!ETHODS .?I.ND MATERIALS

The 3 ewe herds were designated east end (EE),

west end (WE) , and Grace Coolidge (GC) herds (Brundige

198 5). Divisions for the 3 ram herds were northeast

(NE), southeast (SE) , and southwest (SW) . The

sumrr.er/fall ranges of each herd are indicated in Figure

1. Only the GC range extensively overlapped that of the

EE herd on French Creek Canyon and members of both ewe

herds intermingled in this overlap area (Brundige 1985) .

Otherwise, there was almost no range overlap among the

herds and individuals remained associated with their

respective herd and range. Accordingly, sampling schemes

for vegetation and movements were divided with respect to

each sheep herd.

Division of Habitats

Habitats for the sheep herds had previously been

divided into 7 types based on visual appearance (Brundige

198 5) . These divisions were based on presence or absence

of trees, presence or absence of understory, degree of

slope, and degree of rockiness. Mixed grass/forb habitat

type was designated for meadows and consisted of mostly

grasses with some forbs, usually no rocks present, and no

trees present. Riparian habitats were those

characterized by vegetation found near streams and could

include grasses, forbs, rocks, and a mixture of several

9

deciduous tree species and/or ponderosa pine. A

permanent water source was necessary to maintain riparian

areas. Ponderosa pine/grass forb was similar to mixed

grass/forb except that ponderosa pine, or, rarely, bur

oak (Quercus macrocarpa), was present. This habitat was

typical of a coniferous parkland. The ponderosa pine/no

understory category consisted of a ponderosa pine forest

with only an occasional forb or grass present, few rocks,

and was usually located on slopes of less than 40%.

D9ghair/ponderosa pine habitats were similar to ponderosa

pine/no understory, except they were much more dense and

where found contained trees of a uniform height. The

characteristics of this habitat could best be described

as a stand of ponderosa pine whose stems average less

than 15 cm in diameter at breast height (DBH) , grow 1. 5 m

or less apart, and average approximately 6 m in height.

Rocks could be present but no understory was present.

Steep rocky/grass forb areas were typical of open slopes

usually steeper than 35%, with rocks, but no trees

present. Steep rocky/ponderosa pine was similar to steep

rocky/grass forb except ponderosa pine was present. A

description of plant species composition for each habitat

type is given by Brundige (1985) for the EE and GC ranges

for 1984.

10

Characterization of Habitat Types

Physical characteristics for each of the above

habitat types were sampled in all of the sheep ranges.

For each range, 3 or 5 sampling plot centerpoints were

chosen randomly for each habitat type. Within each sheep

range, centerpoints were chosen by assigning a number to

every sheep location in each type obtained during July,

198 5. Numbered locations were randomly chosen to

determine to define a sampling plot centerpoint. In

cases where fewer than 3 sheep locations were available

for a particular habitat type at time of sampling,

centerpoints were chosen within types without locations

near types which had sheep locations. The number of

centerpoints (3 or 5) per habitat was subjectively

determined by the relative abundance of that habitat for

a given range. For types which had relatively small

total areas, 3 points were selected; otherwise 5 were

used. Three sampling plot centerpoints were used for all

of the habitat types in the northern portion of the GC

range located in the Park Headquarters region of CSP

(Fig. 1). Plot centerpoints were positioned within the

respective habitat type to avoid the inclusion of areas

that appeared to be transition zones. Thus, each

centerpoint was assumed to be located in a homogeneous

sample of the habitat type selected.

11

At each sampling centerpoint, a 10 x 10 m plot was

delineated with the edges lying in the 4 cardinal compass

directions. Within this plot, tree density and basal

area, ground cover, overhead canopy, horizontal

obstruction, slope and aspect were measured. Elevations

were estimated to the nearest 10 m from u. S. Geological

Survey (USGS) 7.5 min. quadrat maps.

Mean tree density was estimated by counting the

number of stems for each species in each habitat type and

converting this number to stems/ha. Similarly, mean tree

basal area was estimated by measuring DBH to the nearest

0. 5 cm, converting DBH to basal area, and expressing as

cm 2/ha.

overhead canopy was estimated using a convex

spherical densiometer (Forestry Suppliers, Inc. Jackson,

MS) placed in the center of the plot and using 4

readings. The densiometer was kept level by attaching it

to a camera tripod.

Mean horizontal obstruction of vision was

estimated by using a density checkerboard, 1.5 x 1. 5 m

and marked in alternating black-and-white, 15 cm squares

giving a total of 100 squares. The number of squares

covered were counted and the 4 readings were averaged to

give an estimate of horizontal obstruction for the plot.

A square was considered covered if at least 1/2 of it was

obstructed from vision. The board was read from a

kneeling position to approximate the height of eyesight

for an average bighorn sheep (Risenhoover and Bailey

1985) . The board was placed at a distance of 15 m and

read from the center of the plot in each of the 4

cardinal directions.

12

Ground cover was estimated using line transects

and a 20 x 50 cm guadrat (Daubenmire 1959) . Within each

sampling plot, 4 - 5 m transects were randomly placed in

one of 8 compass directions (N, NE, E, SE, S, SW, W, NW) .

No transect was allowed to overlap any other transect.

Five guadrats were placed parallel and next to each

transect line at 1 m intervals. Placement of the guadrat

with respect to the side of the transect line was

determined by a coin toss . A total of 20 guadrats for

each sampling plot was used.

Ground cover was divided into 7 categories:

grass, forb, shrub, log, duff, rock, and bare ground.

The grass category was comprised of grasses and grass

like forms including Carex spp. Forbs were defined as

herbaceous broadleaved species. Shrubs included plants

with more than 1 woody stem and ponderosa pine seedlings

less than 20 cm tall. Dead and downed trees or branches

greater than 3 cm in diameter were classified as logs.

Duff included dead plant parts and any dead woody

material less than 3 cm in diameter. This category

consisted mostly of shed ponderosa pine leaves. Rocks

were considered as such if they were 3 cm or greater in

their longest axis. The bare ground category included

mostly bare soil and rocks less than 3 cm. Each of

these categories were measured by percent cover within

the quadrat.

Location Sampling

13

Individually radio-marked sheep were located from

July through October 198 5. Five ewes from the GC herd, 4

from the EE herd, and 8 from the WE herd were radio

collared. One ram each from the SE, SW, and NE ram herds

had a solar transmitter attached to its ear. Daylength

was divided into 2 periods: early (0500 hrs to 1300

hrs) , and late (1300 to 2100 hrs) . For ewes, 4 locations

per daylength period per herd were determined using

randomly selected, radio-marked sheep. A radio-tagged

ram was located up to 4 times in each daylength period

that it was sampled. The interval between successive

locations for all herds was a minimum of 1 hour.

Habitat type and map location, as designated by

Universal Transverse Mercator (UTM) longitude and

latitude on USGS 7. 5 min. quadrat maps, were recorded for

each location of a radio-marked sheep. Also recorded

were percent slope, aspect, elevation, group size, and

14

age and sex composition of any associated sheep.

Activity categories, including resting, feeding, moving,

nursing, and standing, were observed in order to

calculate activity budgets and determine whether there

was any differential habitat use among the sheep herds

for each activity considered.

seasonal Home Range Estimation

Seasonal home ranges for each herd were estimated

from locations of radio-marked sheep in each herd. The

minimum polygon method was used to statistically estimate

a home range area and boundaries. Locations that caused

the estimated area to include portions of land where

sheep were never seen, or which lacked any evidence of

their presence, were not used. such locations were

assumed to be excursions of individuals from the

respective sheep herd (Geist 1971) and therefore they

were not included. After home range boundaries were

delineated onto USGS 7.5 min. quadrat maps using the

minimum polygon method, topographic features were

subjectively included to define the home range boundaries

and inclusive habitat types used in utilization

estimation. Using this method, the home range usually

included an entire hillslope to the top of a ridge rather

than only partial hillslopes or valleys. The

subjectively delineated home range encompassed the entire

15

area estimated by the minimum polygon method and is

probably a more realistic representation than the minimum

polygon method itself (MacDonald et al. 1979).

Estimating Proportion of Use

The proportion of each habitat type found in each

sheep herd home range was measured from USGS 7. 5 min.

quadrat maps. Habitat types were outlined from aerial

photographs onto clear acetate sheets, and then traced

onto the quadrat maps using a Map-0-Graph (Art-0-Graph,

Minneapolis, MN) to correct for scale and photograph

distortion. These areas were measured in cm2 using an

area meter (Model LI-3000 Area Meter, Lambda Instrwnents

Corporation) and converted to hectares. Precision of the

meter was +0.02 cm2. Proportion of each habitat area was

calculated by dividing the total area of the home range

into the area covered by a habitat type. The mean of the

slopes for each type was used as a correction factor for

proportion of actual area covered by each habitat, since

slope means for each type across all ranges were found to

be not statistically different (F = 1. 54, p = 0.0756, df

= 22).

Selection or avoidance was estimated using the

proportion of area for each habitat type within the home

range, and the proportion of locations, according to the

methods of Neu et al. (1974) and Byers et al. (1984).

16

Only those locations used to estimate the home range area

were used in estimating proportion of use.

Geist (1971) noted that resting and feeding areas

may be particularly important in determining suitability

of ranges for sheep. Thus, frequencies for each of these

activities were compared among the 7 different habitats

of each sheep herd to determine any differences in

utilization of these habitats. Risenhoover and Bailey

(1985) have also discussed the importance of feeding

areas with respect to group size and distance from escape

cover, where escape cover is defined as precipitous,

rocky terrain (Geist 1971). Accordingly, distance from

escape cover at first sighting for a location were

visually estimated and compared among sheep herds for

each type used for feeding or resting.

Statistical Analyses

Habitat types were analyzed using ground cover and

tree plot measurements and compared using discriminant

analysis. Means for each variable from each sampling

plot were used as observations for this analysis. The

only variable excluded from these analyses was shrub

cover, since coverage was less than 5% in all habitats

sampled. Mean area of each habitat type and mean

distances to escape cover were compared using analysis of

variance (ANOVA, Sokal and Rohlf 1981). Frequency

17

comparisons of numbers of sheep groups observed among

habitat types were made using chi-squared test of

independence (Sokal and Rohlf 1981). Discriminant

analysis and 'ANOVA were performed using appropriate

programs contained in Statistical Analysis Systems

(Goodnight 1986) software. Significance levels for 'ANOVA

and chi-squared tests were 0.05, and 0.10 for

discriminant analysis.

For the methods of Neu et al. (1974) and Byers et

al. (1984) for estimating habitat utilization, expected

proportion of usage {Pio> was calculated by dividing

total range size into each respective habitat area.

Expected frequencies of utilization were then found by

multiplying Pio times the sum of the number of

observations. Significance level to determine

utilization greater than, less than, or in proportion to

habitat type availability was 0.05 .

18

RESULTS

Only 5 locations were obtained for the NE ram herd

during the study period. Therefore, data for this herd

were excluded from habitat and utilization analyses.

Division of Habitat Types

A total of 120 vegetation plots were measured,

which included all habitat types found in each sheep

range (Table 1). Each type was classified as distinct

from any other type within each sheep herd range (Table

2). Also, a type found in one range was not classified

differently from that same type which occurred in any of

the other ranges. These results indicated that observed

differences among the habitat types both between and

within the sheep ranges were also differentiated

quantitatively, according to the variables measured, for

not less than 93% of the observations for each type.

Amount of overlap and relative degree of heterogeneity

for each habitat type using canonical representations of

the first and second discriminant functions are shown in

Figure 2. Habitat types for all ranges combined are

characterized in Figures 3 through 5. Habitat type

descriptions for each sheep herd range are shown in

Appendix I.

Table l. NUJ!'.ber of vegetacion sampl�ng plots for each habitat type located within each sheep herd range in �uster State Park, SD, from AJgust through September, i985.

Sheep Herd east end west end Gra�e southeast southwest

ewe e..,c Ccc lidge ram ram H;;.bi:at '!'ypc herd !".erd e,.,·e he:-d herd herd Total

rr:ixe'.! :,rass/ forb 5 5 5 5 23

pcnderosa pine/ no underscory 5 5 5 5 23

ponder::isa pine/ grass forb 5 5 5 5 23

riparian 5 5 0 16

steep rocky.' grass forb 6 2 0 14

steep rocky/ pcnderosa pine 5 5 5 21 -------------------------------------------·--------------------------'i"ctal 31 27 :s 21 26 120

Table 2. Discri�inant analysis classification summary for each habitat type for all sheep ranges included in Custer State Park, SD, from August through September, 1985. Habitat types are: MF - mixed grass/!orb, PB -ponderosa pine/no understory, PG - pcnde:osa pine/grass forb, RI -riparian, SG - steep rocky/grass fcrb, a�j SP - steep rocky/ponderosa pine.

Number of observations and (percents) classified into types

Pf: : .. F.: SG Sr Tctal

MF 22 0 0 0 l 0 23 ( 95. 65 l 0 0 0 ( 4. 3 5 l 0

PE 0 22 0 0 0 23 0 (95.65) I 4. 3 5 l 0 0 0

?G 0 :2 '.) 0 0 23 0 I 4. 3 :': i I 9:. 6:: i 0 c c

R1 l 0 c 15 0 0 16 ( E.: 5} 0 0 ( 93. 75 l 0 0

SG 0 0 0 0 14 0 H 0 0 0 0 (100.00) 0

SP 0 l 0 0 0 20 2 l 0 I 4. 76) 0 0 0 ( 95. 2q

19

?

7

J

2

0

-1

• l • I � I • I • I ..

I +

I • I • 1

• • .. 4

I • I • I • I •

.

4

" .. , ...

5

s

.. .. '\ 4

4 4

,\

� s

..

.J

J J ] J �J

J.:: � 3

" J :; ·.; 1

J

5 5

s 5

s s

s 5

'5

s

.J

J J

.1

.l J )

J

J

s

s

]

Ii 6

6

6 6

6

2 2

66

"' 6

2

2

2

2 2 :?

2 2

z

2

2 2

z

1 l 1

I I

I I I I I

I I l

l

Co

______ ...,__ _______ ·----------·------------- .. ---------------·---------·-----------...... ------- t, - • -;: o 2 • 6

CANI

Figure 2. Cannonical representations of the first and second discriminant functions for habitat types in Custer State Park, South Dakota, 1985. 1 mixed/grass forb, 2 = riparian, 3.= ponderosa pine/grass forb, 4 = ponderosa pine/no understory, 5 = steep rocky/ponderosa pine. 6 = steep rocky/grass forb. Canl uses vegetation variables grass, forb, duff, bare ground, and canopy coverage. Can2 uses vegetation variables forb, rock, canopy coverage, and duff.

N

0

w (,!)

ll! w >

0 .... w 0 ll! w n.

100

90

BO

70

60 1k �

. ��l 50

40

� @� :!O I il,

� �� '0 1 8� 1 1,1 ,,r

"! fJ 1 0 i� 't

Jt:L M::8 o . .r. i.,, _ 1r 1--· MF" ---� PB --j 1-- PG --I 1-- AI SG - ··-J 1-- SP

r i gur:e 3 . M , ,,1n (+ s!' ) o f 1round covr.1· , c<1nopy cove r , a nd hor: i zon ta l dt! n s i t: y f.01· 'I l l b f qti<l l n sher,p r:<'l ngei:: comb i nr,,J f o r r, ,lch habi tat type i n t:ustcr :;\',H<: P,1 1: k , S D , 1 '1 14 ', . MF" � m i xed /gr,1 ;s s f o i l> , PB = pondr rosa r i ne / n o unde r s t ur y , {''-� " pon<1<' r" r. ,, pine /rir&"'!I f or b , P T · 1 i p;n \ 'l n , SG : ,-• .:ep TO•: !: ·; l q r a s s forb, SI-> � "t�er rnr.l<y / pond,.TOl!III p i ne .

Li fl"re n c,rnopy l') Du f t ,::] !"o r b f.1 a , ,.,.. ., f'.'l Hor i r.ontal il"I Loq I'll! Ror.k ;"'! Sh rub l'i r:ro•rnd [j Co·,e.· rJ f::1 t·l � Dens i ty 1.J U l1

TYPE

< w n: <!'.

�.00000

,100000

....1 200000 < V1 < (l'l

,', \,

f- --- · PO •• • 1 PG

f i gure 4 . Mc,.r, ( .!_ !'!c l of t t·c:,: '"""'b l n .. ,, ,,...,. "·•1".h h"bl n, t '" Y! '" ponder.», ,, p i r,..: / no und-,rstory . �_; p :-:: s t ,....,n rnf"'\.'.y/ s,,:,nd'1rosa f' •

� .. - R J

b" "· ' l -'l r<: n/ha for a l l b i ghorn sheep 1·«wws , - . . . � , ,. ,. $ f" ,, t ,... Pd t· � . !;D, l '>A :1 . PB -

) ·•}f. ... 1•:t'O�d 1 · 1 1 1 1..: / (JCtl.S!.. for t , # , ... , � 1 l f�. , 1 i rt J t �

f:sJ Plnu,. p0ndero"a � Ou., rcus ,,,, , . ·roc .. r p .. � fl<' t u l i< p.:i p 1 {c rou ..

f� Pop•J l u s t t· <'nm lo! d.-,s � M l sc,, l l · !l""'• 1s sp.-,c ics .

TYPF

N N

. 1 I

'"( :c 'Vl

2000

1 �;00

� 1 000 I-I.fl

0 z

500

0

1-- PB - · · I

F'lgur.,. 5 . "'"·"' ( • S P. ) ot numb•? 1 ra nges comb i nr·l r;;r �ach h" b i t , , • ponderos.-,, p i n· · . . , . ) •inderstory , !'< : SP = "teP.p ro, , 1,: , / pondero>1A pl n, · .

j · •• · ll I -· l I · SP --- .. ..

· • f t t �, : str.ms /h" (or a l l h i ih.:i,·n ,,1,, ,,.. p • ,T"' 1 n Cu: : t,<' t SI .d i ,; l',H k. . �0 . I 4 ti ', , PB

t 1<H1d , : ro:t.:�, p i n� /q ctt : . :; t -.H h , i < 'l 1 i 1 · , 1 r 1.. t 1 r, .

� P l nus pond•· ro,;11 � Quercui, m.1c roc1<. rp11 12'.2) f\('tula P"Pi tt:rous

� Popu lus trcmu loldcs· � M l scc l l ,rneous .species .

TvPF

N w

24

Although each habitat type was found to be similar

in structure among all ranges , the proportions of area

for each of these habitats were not similar. There were

no consistent patterns among ewe ranges and ram ranges

except for riparian (Table 3). The amount of riparian

habitat was lower in ram ranges than ewe ranges (F =

3 8. 57, p < 0.0001, df = 12) . This difference may have

been because the EE, WE, and part of the GC ranges

included French Creek Canyon, the only extensive area of

riparian habitat in any of the sheep ranges.

Habitat Utilization

Proportions of use and corresponding estimates of

selection for or against each of the 7 habitat types, by

the methods of Byers et al. (1984), for each sheep herd

are contained in Appendix I. Both the WE and GC ewe

herds selected for mixed grass/forb , while the EE herd

used this habitat in proportion to its availability

(Table 4). All 3 ewe herds selected against doghair

ponderosa pine. The EE and WE herds also selected

against ponderosa pine/no understory. The WE herd was

the only herd that selected for riparian.

For the SW ram herd riparian, steep rocky/grass

forb, and doghair ponderosa pine types were selected

against while the other habitats were utilized in

proportion to their availability. The SE ram herd

:" b:.e J. Pr ·:>por-: ion and area { �.a ) c f e!c!'-. habi tat t ype found 1,,,; i thin each t ;\c : � 5tce? herd no�e : a�ge ! : =� J � ! y : �ro�g� October , 1 9 S 5, !� :�ster S a�e Park, Sou':.� �akc ta.

� : xeC g : l S S /

: : r ::

;:,cn:ierosa ;,ir:e I no ur.de � s cory

�c=-i:!.e!"csa ;,ine, grass fcrb

r � paria.n

st.;;;e;: =ockv1 gr�ss :: or:O ·

s: eep rccky/ i:-=�.de: r osa pir.e

cog,.a : r pc:-:dercsa pine

Tc�al ho�e ra�;e s:.z.e ( ha )

e ast end e...,e !"le:·d

o . : r I " :; . l : I

o . : a 9 ( , 39. 7 9 l

:l. 2 � j < : i. 7. :i S l

0.0 .; 9 ( 1 8 . 7 3 )

0 . 0 2 2 I 1 0 . : C l

0 . � � :. 1 1 ;. s . s e I

0.0 2 6 ( 1 2. 6 8 l

4 9 3 . 95

�est end Grace southeast <!·.·e Coolidge r am � e � d eve herd her�

� - � � s 0 . 0 2 €, 0.0 5 6 1 : 7 . � 6 ) ( 1 S. 3 4 l I :: S. 6 3 l

0 . j 5 9 0. 2 5 4 0 . �96 ( .; j6. · :; ) ( 16 1 . 98 ) ( 3 1 6.5 2 )

C . L J j 0.1 66 0.2 06 ( :. 1 3 . 4 9 ) ( 1 19 . 42) ( : 3 1 . 0 7 )

C.0 3 � 0.0 2 5 0.009 I :: ': . 32 l ( 17. 9 0 l ( :- . 9 7 l

o . o : o 0.009 0.0 : , i c l.S6 J ( 6. 2 0 l ( 3 �. 5 2 J

0 . 3 :9 0 . j 6 9 0.101 ( 3 52.� 7 ) ( 264.0 9 1 ( 6 � . ) .; )

) . l � 2 0.1 : 3 �·. 0: :, ( 1 56., 0 J ( 109. 7 :, l I 4 7. 7 3 J

l l 0 4.05 7 1 7.62 6 3 5.7 8

sout•·.,,;est ram �erj

0.0 5 5 ' :; l . 3 � )

0 . 1 7 9 ( 1 9 6.5 7 )

0 . ! C � ( 3 3 8.97 )

o . 0)6 i 2.: :i i

O . C c l ( 2 3 . 1 5 )

J. 3 7 3 '. 4 1 2 . 6 a ;

-:, . -:--: c ( 6 5 . 9 2 )

l l 0 7.2S

Tal: lc 4. Se l;;;ct. ic:i i:::r a::d aga i:lst l �.a!:itat types by :lock;· �ou,.t a : n bighorn s�eep �erds in Cus ter S t a te Park, SD , f rom July through Octo�e r, 195:,.

Sheet:, Herd east e�d west e:id Grace sou t heast southwest

�we e",e Cc,olidge ra1r, ram herd �erd e�e herd herd herd - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

;,i: xed g r ass/ : orb

;,cnde:�sa ;,ir.e / no u:iders tory

ponderosa pine/ grass !crt:

stee;: roe��·,: .:;r:1s.s f e r�

s : cei:; rocky/ pci.'de rcsa pi r,e

dc�::ai r p-:-r.de rosa ;,ine

0 +

0 0

0

0

... 0 0

0 0

0 0

0

0 0

0

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -O i d ca:es :i o select�cn

_ ::i ca:es se :e::t �c:i - � - ? :·. a � i : a t :ype 1 j cates se:ec:icr. a � = : �s: a �aritac type

..

25

likewise selected agains t doghair ponderosa pine and

riparian but, in addition, selected against ponderosa

pine/no unders tory, while selecting for ponderosa

pine/grass forb habitat.

26

Pooling the 3 ewe herds and both ram herds

resulted in a difference of habitat utilization than

those found among individual sheep herds (Table 5). For

the pooled ewe herds, both the mixed grass/forb and

riparian habitats were selected for while doghair

ponderosa pine and ponderosa pine/no unders tory were

selected agains t. Doghair ponderosa pine and riparian

were selected agains t by the pooled ram herds, while

ponderosa pine/grass forb was selected for.

Activity Budgets

Feeding was the mos t frequent activity encountered

for all herds except the SW ram herd (X2 = l S . 88, p <

0. 01 , df = 3, Table 6) . Feeding was the second mos t

frequent activity for the SW herd and was probably an

artifact of small sample size. Standing was not a

frequent activity for any herd. The remainder of the

activities observed were divided between res ting and

moving and were similar among the herds (X 2 = 3.38, p =

0.4981, df = 4).

Res ting areas for all herds (Table 7) were found

most frequently in steep rocky/ponderosa pine habitat,

Table 5 . Selecticn a�d avoidance o: l':abitat t'.{Pes by pooled ram and ewe bi;horn sheep herds i n Custer State Park , SO, from July tr.rough October , 1 98 5 .

Habi tat !'ype pool ed

e·..ie herds pool ed

ram herd -- - - - - - - - - -- -- - - - - - - - - - - -- - - - - - - - - - - - - - ---- - - - - - �- - - - -

pcr.derosa pine; r.c unde rs tory

ponde rosa pine/ grass f:;;rb

r ipar ian

s : eep r::ck.1!

g: ""ss f orl::

s t eep rock:rt pcr.dercsa ;:, :.ne

ponderosa pine

0

0

0

0 0

- · · - - - - -- - - - - - - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - -- - - - - - - - -- - - - - - - - - - - - - - - -

O ird�cates no se lection : nd i cates selection fer a habi ta� :,�e indicates se .ection aga inst a hazi:at type

Table 6 . Proport ion t ro . cf observatio�s ) o f behavior categories for bighorn raT. and ewe sheep he rds in Custer State Par k , SD, f rom July through October , 1 985 .

Activi ty

Re st:.ng

Moving

Standing

Feed ing

':o � a l �tiJ';.'::er

Obse rvat ior:s

east enc e'-'e herd

� . 2 4 '7

( 1 8 )

0 . l � 1 ( : 1 1

;J . 06 8 I 5 l

0 . 5 . H ( ) 9 l

i l

Sheep Herd west end Grace southea st

e1<,e Coo lidge n,1n herd e�e herd herd

0 . loO 0 . 1 � 1 0 . 206 ( 1 6 ) ( B ) ( 7 }

0 . 1 60 o . 208 0 . 36 2 l i c l I 1 1 l ( 8 )

0 , :;57 0 . 1 5 1 0 . 0 2 9

( 6 ) ( 9 l ( 1 1

O * S i 3 {) . � 9 : 0 . 5 2 S ( :, : ) ( 2 6 l ( :. s )

89 5 ) 3 �

a - - represents no cbserved occur re�ces .

southwe s t ra..i:"l herd

0 . 500

( 7 )

o . 2 1 4

( ) )

_ _ a

0 , ? 1!6 H I

1 4

2 7

';al:le 7 . Re l a t i ve f ::eq-.:e r.cy ( no . obse:-va t i ons ) of res ting act i vity I::: Rc;:ky �ount a i n bighorn s r.ee;: he : ds fer each r.abi tat type i n Cus ter S t a � e Pa r k , S D , from July th::ough OCtobe i; , 1 9 8 5 .

H'lbi : a : Ty;:,e

r.,ixed g: a s s / forb

ponderosa pine / r.o -...nde ?:- s-::cry

ponderosa pine / grass fo:-b

r _par ia�

s teep ::ocky/ ; , ass forb

s teep rocky/ ;: � r.t;?rosa pine

r:!cg� 5 ,;. �

;:..o::. :: : :- : 3-:! p : :-.�

east e :-.d e;,;e � e : d

0 . 00 ( 0 )

0 . l l ( : )

0 . 2 9 ( 5 )

o . oc ( l

0 . 1 1 \ - )

0 . 50 ( 9 )

,· . c ,: ( ( i

�es : e:-.d G:ace e�e Cooli d;e her� c:..tc r. t: : :i

O . Oo .l . 1 3 ( 1 ) ( l )

•J . 06 0 . 25 ( l ) 1 .: )

O . Oo 0 . 25 ( 1 ) ( 2 )

0 . 06 o . co

( l ) ( 0 1

() . 00 0 . 00 ( c ) ( 0 )

0 . 7 :, 0 . J 8 ( l : ) \ ) )

0 . O? c . so ( ( ) { 0 1

s::�t�e a s t ra..T. l:'!?rd

o . oo ( 0 )

'.) . 1 4 l � )

0 . 57 ( 4 )

C· . ".10 ( O J

o . oo t O l

0 . 2 9 ( 2 '

c '· ( )

sout�.west ram herd

0 . 00 ( 0 )

0 . 2 9 ( 2 )

0 . 1 .; ( l l

o . co ( 0 )

o . oo ( 0 )

0 . 57 ( 4 1

0 . 1) 0

( 0 ) -- - · - - - �------ - - ----- - - - - - - - - - - - - -- - - - - - - - - - - - - -- - - _ _ _ _ ... _ _ _ _ _ _ _ _ _ _

28

29

except for the SE ram herd , which used ponderosa

pine/grass forb ( x2 = 13 . 0 4 , p < 0. 05, df = 6) .

Utilization analyses revealed that only the WE ewe herd

selected for steep rocky/ponderosa pine as resting sites

( Table 8). Only doghair ponderosa pine was consistently

selected against by all herds.

Feeding areas were less consistent among herds

( Table 9) , and included riparian , ponderosa pine/grass

forb, and mixed grass/forb habitats as the most

frequently used feeding habitats . The EE ewe herd spent

most of its feeding time in ponderosa pine/grass forb but

also utilized steep rocky/ponderosa pine and mixed

grass/forb to a lesser extent . The WE ewe herd fed

mostly in riparian and mixed grass/forb and, to a much

lesser extent, in ponderosa pine/grass forb. The GC ewe

herd fed most frequently in mixed grass/forb and also

ponderosa pine/grass forb and riparian habitats. Only

ponderosa pine/grass forb was used extensively for

feeding by the SE ram herd while the SW ram herd used

mixed grass/forb more frequently and, to a lesser extent,

both ponderosa pine/grass forb and riparian, although

again, this may only be an artifact due to small sample

size . Selection of feeding areas, determined using the

methods of Byers et al. ( 1984 ) , generally followed trends

found in frequency comparisons ( Table 10 ) . All herds

.....

Tab le 8 . Select ion and avoidance l o f habitat types used for resti ng s i tes by Rocky Mountain bi ghorn sheep herds in Custer State Park , SD, f rom July thrcugh october , 1 98 5 .

mixet grass , forb

ponderosa p ine/ no •-r.dersto:-y

ponce res a pine/ grass forb

r i p;; d a n

steep rocky/ grass !'c:-b

stee? rocky/ p::cr.c::;;,::::,sa pir.e

doghai r por.::erosa pine

Sheep He rd east end ._,est end Grace southea s t south...,es t

e1,1e e·.;e Cool idge r am r am herd herd e...,e herd herd herd

0 0

0 0

0 0 0

0

0

0 0

0

0

0

0

0

0

0

0

--------------------------- ------------------------------ -----------l 0 indica:es no selection

+ 1ndi�ate s se lection for a habitat t1-pe i n� ica:es select ion against a hab:ta: tj-pe

Table 9 . Relative f requency I nc. observations ) o f f eeding activity by Rocky Mountai n bighorn sheep herds for e ach habit a t type i n Custer State Park , SD , f rom July through Octobe r , 1 9 8 5 .

Habitat Type

Sheep Herd east e nd west end Grace southeas t southwes t

ewe ewe Coolidge r am ram herd herd ewe herd herd herd ---- -------------·------------------------·---------------------------

ro : xe:! grass/ 0 . 26 o . n o . j ;> O . l i 0 . 50 f orb ( 1 0 ) 1 1 7 ) ( 9 ) 1 3 ) I 2 l

ponderosa p i ne / 0 . 03 0 . 00 0 . 0 4 o . oo 0 . 00 r.o under story ( l ) 1 0 ) ( l l 1 0 1 ( 0 )

po:1derosa pine/ o . 4 1 0 . 1 6 o . ) 1 0 . 61 0 . 2 5 g rass forb ( 1 6 ) I 8 ) 1 8 I 1 1 1 l 1 1 )

; :.pa:- : .! n 0 . 0 5 ;; . H 0 . 2 3 o . oo o . �s ( ,: ) ( .: 2 1 ( 6 1 ( 0 ) I l )

s �eep rock,· / 0 . 0 5 :l . C ? 0 . 00 0 . 1 1 0 . 00 grass forb ( 2 ) ( : l ( 0 l 1 2 l ( 0 )

s teep rocky/ 0 . 2 1 0 . 06 0 . 08 a . 1 1 0 . 00 ponderosa p i ne ! a l l 3 I ( 2 ) ( 2 ) ( 0 )

doghair 0 . 00 0 . 00 o . oo o . oo 0 . 00 pcndercsa pir.e ( 0 ) ( C l l 0 ) ( 0 1 1 0 ) --------------------------------- --- ---- ------------------------------

3 0

Table 1 0 . Se l ect ion a nd avoidance l of habitat types used for feeding by Rocky Mountain bi ghorn sheep herds in Custer State Par k , SO , f rom July through OCtober , 1 9 8 5 .

Sheep Herd ea s t end wes t end Grace s outhea st southwes t

ewe ewe Coolidge r am ram Hat : : � t Ty-pe herd herd ewe he rd herd herd

m:. xed grass / forb

ponder osa pine/ no understory

ponderosa pine / grass forb

r iparian

steep rock1/ grass forb

steep rocky/ ponderosa pine

dog�ai r p<::r:de�osa pine

0

0

0

0

0

l O �d cates no selection

+ +

0 0

0

0

nd ca�es se lect ion for a habitat tYJ:e nd cates se lection agai n s t a hab i t at type

0

+

0

0

0

0

0

3 1

32

selected against ponderosa pine/no understory and doghair

ponderosa pine types as feeding habitats .

Distances from resting sites to escape terrain

were mostly consistent among the herds , since the most

frequent habitat used for resting also consisted of one

type of escape terrain, steep rocky/ponderosa pine. Mean

distances from these resting sites to escape terrain for

al l herds except the SE ram herd were less than 10 m.

For the SE ram herd, which utilized ponderosa pine/grass

forb most frequently for resting sites , the mean distance

to escape terrain was 83 m.

Mean distances from feeding areas to escape

terrain were more variable than those from resting sites,

depending on which habitats were utilized most frequently

for feeding (Table 11 ) . Mean escape distances among the

ewe herds were not significantly different (F = 5. 02, p =

0. 0632 ) among the habitats most frequently used for

feeding. This was also true for the ram herds (F = 1. 58 ,

p = 0. 2431 ) , but the number of observations for the SW

ram herd (2 ) were too small to make reliable comparisons.

Distances to escape cover from most frequently utilized

feeding habitats were significantly greater for rams than

ewes (F = 4.99, p = 0. 0009 ) .

Table 1 1 . �ear. dis tance ( no. observations) [ group si ze ) between locations cf �ora;ir.g sheep and escape terrain for all bighorn sheep herds for each � . .;.:: i ::. a : : ;-pe : n Cu s ter s : a :.e Park , SD , from July through Octol::er , 1 985.

�a7��

. � �'.3!:-: :. a :. �·,-'FC

,... . ·, .- - ; : � s s . ! c ::0

pc:: d e rcsa pi r.e/ r.o ur.dc r s c o r z

pcr.derosa p � r.e/ g:-ass fcr b

: i ;l r i a�

s:eep !'OCi<:i/ ;rass :orb

s � e�p reek·;: � : :-.�e r :: s i ... . - o

J'" .. · · -

Sheep Herd ease er.d wes : e nd Grace southeast southwes t

ewe e ... ·e Cool idge rarn rar:, her� herd e�e herd herd �erj

-; j . -5

( 1 0 l [ l 4 )

l S . O ( 1 )

[ 11 J

3 7 . 2 3

( : 6 ) r -

. J '

: : . :, ( : j

[ 6 ]

5. 0 ( 2 )

[ 5 j

6 . 3 ( : } [ s l

- • ? I � • •

( 1 7 I [ H J _ _ b

"6. 9 (B J

i 1 � )

: .; . 6a ( : � )

[ 7 J

70 . 0 1 1 l

! 1 o I

o.o ( J l � 9 �

4 j . .;a ci E . 0 � ?. : a. ( 9 ) ( 3 ) ( 2 )

[ 1 3 J ! 3 J [ l J

� 0 . 0 ( l ) [ 2 J

2 , . 5 80. 6a ':1 9. 0 I 5 ) ( 1 1 l ( 1 )

'. 1 1 J [ 5 J [ :, )

20.B l ; . 'j ( 6 ) I : i [ 7 J [ 1 J

20. 0 ( 2 )

[ 3 l

0.0 0 . 0 ( : ) ( 2 l i l c J l } j - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -- - - - - - -- -- - - - - -- - - - - - - - - - - - - - - - - -

a i r.dica tes �::st f r eq-�ent ly utili �ed f oraging habit 3t. -- i r.dica:es r.o observed occur rences.

3 3

3 4

DISCUSSION

Two predictions of the hypothesis that sexual

segregation of bighorn sheep occur to reduce intersexual

habitat competition (maintenance of home range fidelity

between the sexes and similarity of physical

characteristics for each habitat type among sheep ranges)

were supported by the data in this study. Although the

radio- tagged ram in the SW herd was observed on the WE

range, no other members of the SW herd were found on the

WE range. This ram was relatively young (4-years-old)

and might not have completely established his home range,

resulting in a lower ram herd affinity and increased

wandering (Geist 197 1). Otherwise, herd members

maintained high fidelity to their respective range, and

where ranges did overlap, temporal separation was

maintained. Maintenance of separation during the swnmer

and fall supported the argument that intersexual habitat

competition occurred and was reduced by ram and ewes

occupying separate ranges. If reduced habitat

competition were not important , then greater spatial

overlap of ranges would be expected , such as that found

in the Ya Ha Tinda herd by Morgantini and Hudson (198 1)

during the winter, or that the sexes would have

differential habitat requirements.

Similarity of physical characteristics for each

..

3 5

habitat type among sheep ranges demonstrated that

establishment of each sheep range was not restricted to

any particular types for any herd. This lended support

to the assumption that the ranges were not qualitatively

different, at least in terms of 3-dimensional structure.

It also supported the asslli�ption that ranges presently

occupied by CSP bighorn herds were not established

according to differential habitat preferences or

requirements between sexes.

Although forage quality was found to differ

between ram and ewe ranges in a study by Shank (1979) , he

suggested that these differences were too small to

explain segregation based on these differences and found

no basis for suggesting that different habitat

requirements existed between sexes. However, both

Morgantini and Hudson (198 1) and Geist and Petocz (1977)

reported differences in habitat occupation between rams

and ewes during the winter for 2 different populations.

In the herd studied by Geist and Petocz (1977) , rams were

found on areas with more grassy slopes, while ewes

occupied steeper, more rocky terrain. Rams occupied more

rocky and steeper terrain than ewes in the Ya Ha Tinda

herd (Morgantini and Hudson 1981) . If both sexes

required similar habitats, then habitat occupation should

have been similar between the sexes, whether they

-

36

segregated or not , and should have been consistent over

the geographical range that bighorn sheep inhabit

( Morgantini and Hudson 1981). Since habitats occupied by

each sex were not consistent , these two studies support

the conclusion that rams and ewes do not have different

habitat requirements . Therefore , rams and ewes may be

equally likely to establish seasonal ranges over similar

habitat types and potentially compete with each other for

resources within those ranges.

In order to demonstrate that competition for

habitat resources occurred between the sexes , the

prediction was made that habitat types were utilized with

similar frequencies , between the sexes. However ,

utilization analyses for habitat types did not support

this prediction for comparisons among the herds (Table

4). Although most types were utilized in proportion to

their availability for each herd , when there was

selection for or against a habitat type , types selected

were inconsistent among the herds, except for doghair

ponderosa pine.

Utilization analysis between sexes for pooled

herds suggested differences of habitat utilization

between rams and ewes ( Table 5). However , since habitat

utilization was different for each herd, regardless of

sex , pooling was not considered justified to make

3 7

comparisons between sexes .

Simple comparison of habitat type utilization for

all sheep locations may not be adequate in determining

whether intersexual competition occurs or not, since all

behavior categories were lumped for the utilization

analyses. Competition may be critical for only a few

resources, and since Geist (1971) noted that feeding

areas and resting sites were important factors in

determining sheep distribution, habitat utilization

analyses for these two behavior categories would also be

important in evaluating whether competition occurred

between the sexes for these two resources .

Comparison of habitat utilization among the herds

for feeding areas did not support the prediction that any

habitat type selected for feeding areas would be similar

among the herds (Table 8) . Also, the analysis did not

demonstrate that ewes consistently selected for any

particular habitat type for feeding that were different

from rams ; thus, there was no indication that habitat

requirements for feeding areas might be different between

the sexes . Utilization of habitats for resting sites

suggested that some types were not suitable for this

behavior (Table 11) , but lack of selection for any of the

other habitat types did not support either similarity of

selection among the herds or that there were intersexual

...

3 8

differences of habitat selection for resting sites.

One problem with using utilization analysis for

establishing whether habitat competition occurred between

sexes was that only the results of selection for or

against a habitat type were useful to make comparisons.

The test provided no information regarding differential

frequency of use between habitat types, only whether a

type was utilized more than, less than, or in proportion

to its availability. Thus, no information could be

obtained by comparing, among herds, types which were

utilized according to proportion of their availability.

Another problem with using results of habitat

utilization from this study for determining whether

intersexual competition occurred or not is the small

number of observations used to estimate habitat

utilization. Byers et al. (1984 ) suggested that expected

frequency of usage should be 5 or greater, in all

categories, to insure adequate sample size for their

utilization estimator. Expected frequencies of several

habitat types for every sheep herd were less than 5,

possibly leading to biased results, where there were not

enough observations to establish whether selection

actually existed or not (Table 12 ) .

•

Table 1 2 , Expected number o f occurrences o f use for each habita t type by Rocky Mountain bighorn s heep herds in Custer State Park , SD , f rom July through Octcber , 1 98 5 .

Habi tat Type

Sheep Herd east end '"'est end Grace southeast so'.l.th,.,est

ewe ewe Coolidge ram ram herd herd ewe herd herd herd ----- - ------------------ -------------------------------------- --------

m: xed grass/ ! c r b c O li'

ponderosa pine/ no under story 2 1 6 1 3 1 7 2

ponderosa pine/ grass forb 1 7 9 8 7 3

riparian 3 3 1 0 0

steep rocky/ ·;;rass forb 2 2 0 2 0

stee;, rock;-/ ponderosa pine 1 8 2 7 1 9 3

:; :,;;:-. :. : :-por.cerosa pine 2 1 2 8

3 9

40

Comparison among herds of types used most

frequently for resting and feeding provided some basis

for supporting similarity of habitat use between the

sexes. Although utiliz ation analysis showed that only

the WE ewe herd selected for steep rocky/ponderosa pine ,

this type was most frequently used as resting sites for

all but the SE ram herd. This herd used steep

rocky/ponderosa pine second to ponderosa pine/grass forb.

This suggests that steep rocky/ponderosa pine was the

most important habitat type for resting sites among CSP

sheep herds .

While there was less consistency in most

frequently used habitat types for feeding , riparian ,

mixed grass/forb , and ponderosa pine/grass forb were the

most important types for the sheep herds (Table 9 ) .

There was no evidence for intersexual differences of

types used for feeding as each ewe herd and each ram herd

used a different type most frequently. This suggested no

differences in habitat requirements between rams and ewes

in those types most used for feeding . However , since

only these 4 types were most frequently used by all of

the sheep groups , then evidence of intersexual

competition for feeding habitats can be suggested . This

provided support for the hypothesis of segregation to

reduce competition between the sexes and conformed to the

assWTiption that habitat types were used with similar

frequencies by the sexes.

41

Inconsistencies of habitat types used for feeding

by ram and ewe herds may have been influenced by size of

groups within herds . Risenhoover and Bailey (1985) found

group size and distance to escape terrain important in

predicting foraging efficiency and distribution of

bighorn sheep. Small groups (1-5 individuals) were less

efficient than mediWTI (6-10 individuals ) and large (>10

individuals) groups . Small groups were also rarely found

foraging very far from escape terrain, while large groups

were found to forage at greater than expected distances

from escape terrain . Thus, group size may be important

in determining how efficiently bighorn sheep are able to

exploit available foraging areas . If group size is too

small , then foraging areas may be restricted to areas

relatively close to escape terrain. Since a maximWTI of 7

sheep comprised the SE ram herd and the SW ram herd

consisted of 4 individuals , while ewe herd sizes were

much larger (Table 9) , utilization of feeding areas may

have been restricted for the ram herds. However , rams

were found to forage much farther from escape terrain

than ewes , even though average group size of rams was

considered small . Thus , rams were considered not

excluded from foraging areas located at relatively great

4 2

distances from escape terrain because of small group

size . The failure of predicting group si ze and distance

to escape terrain in CSP rams and may have caused

inconsistencies in utili zation of those types used for

feeding .

Results for habitat types used for feeding among

the herds were especially important since forage

competition is probably the most important form of

habitat competition between the sexes , and since

reproductive fitness of females is considered to be most

dependent on foraging efficiency ( Clutton-Brock et al.

1982) . The results from this study supported the

predictions that the sexes occupy home ranges that share

similar physical characteristics for each habitat type

and that spatial and temporal fidelity of home range

occupation is maintained. The data also suggested that

both sexes utilized habitat types with similar

frequencies , but this conclusion is tentative at best ,

given the paucity of data for the ram herds . The data

also led to the conclusion that rams and ewes do not

exhibit differential habitat requirements , a result

previously reached by Shank (1979) . On the other hand ,

Clutton-Brock et al . (1983 } concluded that red deer

(Cervus elaphus } sexes did segregate according to

differences in habitat preferences suggesting that

....

failure to support the hypothesis proposed by Geist and

Petocz (1977) using data from CSP bighorn sheep may be

unique only to this study.

4 3

Although the hypothesis of segregation to minimize

habitat competition between rams and ewes (Geist and

Petocz 1977) can explain maintenance of sexual

segregation year-round, it does not preclude separation

in order to reduce agonistic interactions among rams and

ewes when reproduction is not possible. Geist (1971)

described the forms of each age and sex in a social

context. Basically, older rams ( 8 years and older) are

the mature forms of bighorn sheep. Mature in this case

means physical, psychological, and social maturation.

Older rams regard all smaller rams, adult ewes,

yearlings, and juveniles merely as undeveloped rams and

treat them as such (Geist 1971). Estrous ewes and

subordinate rams react to aggressive advances by larger

males with a set of specific behavior patterns which

allows the aggressor to express its dominance .

Nonestrous females and lambs simply withdraw and leave

the intentions of the aggressive male incomplete. These

encounters may result in the aggressor (male) chasing the

recipient (female) for some distance thus increasing

energy expenditures for ewes and lambs . Geist ( 1971) has

also documented that rams spar for dominance year-round

44

and interprets this to mean that rams may compete for

dominance, not females . Thus, males that have become

dominant in ewe herds can be detrimentally stressful to

pregnant or lactating ewes by remaining in ewe herds and

continually asserting their dominance. Younger rams (3-5

years old) leave female herds only after becoming

dominant to all members of their herd, then join ram

herds for the duration of their lives (Geist 1971). Any

further social interactions with nonestrous ewes is

meaningless for these dispersing rams. Further dominance

can only be attained by interactions with larger males.

It is suggested that rams may segregate from ewes

in order to reduce agonistic behaviors between the sex

groups. By explaining sexual segregation in bighorn

sheep in this manner, segregation can be maintained

during the nonbreeding time of the year without invoking

altruistic behaviors on the part of rams, where rams

occupy poor quality ranges in order that ewe herds may

occupy higher quality ranges. It would also explain

inconsistencies of habitat utilization for feeding and

resting sites found between the herds in this study by

the fact that these inconsistencies would become

unimportant. The other two assumptions, home range

fidelity and similarity of habitat types within the

ranges of both sexes, would follow from maintaining

segregation in order to reduce agon istic interactions

be tween rams and ewes .

4 5

Critical tests to d iscriminate among the

hypotheses which explain segregation are s till needed as

th is study is inadequa te to do this , or even fully

support the hypothesis of reduced hab i ta t compe tition .

Repea ted stud ies as ou tlined here are needed to de term ine

any patterns of cons is tent d is tribu tion and hab ita t

utilization across d ifferent b ighorn sheep herds.

Concurren t data to establish forage quality and /or

quantity differences , be tween the sexes , are needed for

d ifferent herds . A lso, s tud ies to dec ide the importance

of ram -ewe soc ial interac tions dur ing the breed ing and

nonbreed ing seasons would be necessary to de termine

whe ther energy expend itures from these encoun ters would

be great enough to warran t them as an explana tion for

sexual segregation. Regardless of wh ich hypo thes is is

mos t fully supported , the accepted explana tion should be

adequate to comp le te ly explain sexual segregation found

in Rocky Moun tain b ighorn sheep and, probably , all of the

ungulates.

4 6

MANAGEMENT RECOMMENDAT IONS

The behavior and habitat utilization of t he CSP

bighorn sheep population were found to be similar to

other Rocky Mountain bighorn s heep herds . Since ram a nd

ewe herds maintained spatial segregation t hroughout t he

nonbreeding portion of the year, it is concluded t hat a

need for areas large enough to support separate ram and

ewe ranges is necessary for mainte nance o f a bighorn

population . Herd sizes would depend o n t he area o f

available habitat for each herd. Ewe herds apparently

require rugged terrain (ie . escape cover) closer to

foraging areas tha n rams did. Thus, when considering

habitats for bighorn sheep, areas which might appear as

suitable foraging sites may not be utilized a nd could not

be i ncluded as bighorn sheep habitat . Habitat vegetation

types may not need to be similar for ram a nd ewe ranges,

but this cannot be considered conclusive from this study .

CSP rams were found to form 3 distinct herds where

t he herds were not observed to exchange members during

t he summer a nd fall . Since hunting withi n CSP is

allowed, and rams are taken irrespective o f herd

membership , numbers o f each ram herd , rather than just

the ram population, should be monitored care fully to

i nsure that one herd is not accidentally eliminated . I n

t he event one herd was, one range o f bighorn sheep

habi ta t would be effec tively dele ted from the CSP herd

un til individuals unfamiliar with that range learned to

use i t.

47

LITERATURE CITED

Anderson, S .H. and H.H. Shugart, Jr . 1974. Habitat

selection of breeding birds in an east Tennessee

deciduous forest . Ecology . 55 : 828-837.

Brown, J.H. and A .C. Gipson. 1983. Biogeography. c .v.

Mosby Co., St . Louis, MO . 643 pp.

Brundige, G.c . 1985. Lungworm infections, reproduction,

and summer habitat use of bighorn sheep in Custer

State Park, South Dakota. M . S. Thesis, South Dakota

State Univ ., Brookings, SD 54 pp.

Byers, C .R., R.K . Steinhorst, P . R. Krausman. 1984 .

Clarification of a technique for analysis of

utilization-availibility data. J. Wildl. Manage.

48 : 1050-1053 .

48

Clutton-Brock, T .H., F .E. Guinness, and S.D. Alban. 1982 .

Red deer -- behavior and ecology of two sexes . Univ.

Chicago Press, Chicago, IL. 396 pp .

Daubenmire, R. 1959. A canopy-coverage method of

vegetational analysis . Northwest Sci . 33 : 43-64 .

Geist, V . 1 97 1 . Mountain sheep -- a study in behavior and

evolution. Univ. Chicago Press , Chicago, IL . 383 pp.

----- 1974. On the relationship of social evolution and

ecology in ungulates . Amer . Zool. 14 : 205-220.

----- and R.G. Petocz. 1977 . Bighorn sheep in winter : do

rams maximize reproductive fitness by spatial and

........

habitat segregation from ewes? Can . J . Zool .

55 : 1802-1810 .

----- and P .T . Bromley. 1978. Why deer shed antlers . z .

f . Saugetierkunde . 4: 223-231.

Goodnight, J .H. 1982 . ANOVA, DISCRIM Procedures in A .A .

Ray, ed . SAS user ' s guide : statistics . SAS Inst.

Inc ., Cary, N. C . 58 4 pp.

Hogg, J. T. 1983 . A study of social organization, social

behavior, and population dynamics in Rocky Mountain

bighorn sheep on the National Bison Range, Moiese,

Montana . Job Completion Report W-120-R-13, BG-7. 0 .

University of Montana, Missoula, MT . 62 pp.

49

MacDonald, D. W. , F. G . Ball, and N .G. Hough. 1979 . The

evaluation of home range size and configuration using

radiotracking data . in C. L . Arnlarer and D. W .

MacDonald, eds. A handbook on biotelemetry and

radiotracking. Pergammon Press, Ltd . NY.

Morgantini, L. E. and R. J. Hudson. 1981. Sex differential

in use of the physical environment by bighorn sheep.

Can . Field-Nat. 95 : 69-7 4.

Murie, A. 194 4. The wolves of Mt. McKinley, Fauna of the

National Parks of the U. S. , Fauna series No. 5

Washington, D. C ., U. S. Dep . Int., National Park

Service.

Neu, c . w . , C. R. Byers, and J. M. Peek. 197 4. A technique

for analysis of utilization-availibility data . J .

Wildl . Manage . 38 : 541-545 .

so

Nudds , T.D . 1977 . Quantifying the vegetative structure of

wildlife cover . Wildl . Soc . Bul l . 5 : 1 13-117 .

Ricklefs , R . E . 1979 . Ecology. Chiron Press , Inc . New

York , NY 966 pp .

Risenhoover , K . L . and J . A . Bailey . 1 985 . Foraging ecology

of mountain sheep : implications for habitat

management . J . Wildl . Manage . 49 : 797-804 .

Shank , c . c . 1 979 . Sexual dimorphism in the ecological

niche of wintering Rocky Mountain bighorn sheep .

Ph . D . thesis , Univ . of Calgary , Calgary, Alberta .

193 pp .

Shannon, N . H . , R . J . Hudson , B . C . Brink , and w . o . Kitts.

1975 . Determinants of spatial distribution of Rocky

Mountain bighorn sheep . J . Wildl . Manage . 39 : 387-40 1 .

Sokal R . R . and F . J . Rohlf. 1981 . Biometry , 2nd ed . W . H .

Freeman and Company, San Francisco , CA . 9 16 pp .

Stel fox , J . C. 1976 . Range ecology of Rocky Mountain

bighorn sheep . Can . Wildl. Serv . Rep . Ser . 39 .

Wittenberger , J . F . 1981. Animal social behavior .

Wadsworth, Inc . , Belmont , CA . 782 pp .

51

APPENDIX I

-i 1:: : e A ! . Occur re�=e c� ha bi ta t occupa: �an by the e a st e nd ewe herd in C;;s :er St.Hi! Par k , SD , f rom .:uly throu;h .Jctobe r , 1 9 8 S .

Habitat Type

:, : xe= gra ss; !or!::

ponderosa p i ne / no u:-.derstc:-y

ponderosa pine/ gras s forb

r i parian

s teep rocky/ grass forb

steep rocky/ pondercsa pine

dogr.ai r ponderosa p i ne

:'ot a ls

Total Area No . ( ha l Groups

Observed

6 6 . 1 2 1 0

1 ) 9 . 7 9 5

1 1 7 . 55 24

1 8 . 7 3

1 0 . 50 4

1 1 8 . 58 27

1 2 . 68 0

4 8 3 . 9 5 7 2

Actual Proportion o f Usage

C Pi I

0 . 1 3 9

0 . 06 9

0 . 3 3 3

0 . ;, 2 8

C . C 5 6

0 . 3 -; �

0 . 000

Expected Proportion o f Usage

( Pf o l

0 . 1 ) 7

o . 2 a 9a

,:i . 24 3

0 . 0 3 9

c . 0 2 2

Bonferroni I nterva l s

for Pi

0 . 0 2 9.$..?15_0 . 2 4 9

0 . 0 00.$..?25.0 . 1 50

0 . 1 8 4.$..?35_0 . 48 3

O . OOOS,.P4i0 . 0 8C

o . 0005.i::3io . 1 2 e

o . 2 4 5 0 . 2 2 2.$..?6!0 . :: 2 8

0 . 02 6a O . OOOiP7iO . OO O

- - ------- ------- ------ - - - - - - - - - - - - - - - ----- - - - - -- - ·----- ----- - - - -- - - - - - -a ind i ca tes select ion against a habitat type a t the 0 . 0 5 sign i f i ca nce

leve l .

Table A 2 . Occurrence o f h abi t a t occupation by the west e nd ewe herd i� Custer Stat e Pa rk , SD , f rom July througr. October , 1 98 5 .

Habita t: Type Tota l Area No . ( h a } Groups

Observed

Actua l Proportion o f Usage

( Pi I

Expected Propor t i on o f Usage

! Pio l

Bonferron i I nterva ls

f or Pi

- - -- - - - ------------- ---- - - - - - - - ---- -- ---- - ---- ----- - - - - - ---- --- - - - - -mi xed grass/ f o r b 27 . 7 6 1 7 0 . 1 % o . 02 sa 0 . 0 B2iP1iO . 3 1 3

ponderosa pi net 0 . 3 59 b no unders t.ory 3 9 6. 7 5 6 0 . 070 0 . 0 00s.F2iO. H4

ponoeros a p i ne / grass forb 1 1 3 . 4 9 1 1 0 . 1 2 8 0 . 1 0 3 0 . 0 3 1.5.p35_0. 2 2 5

r i pa r ia n 35 . 3 2 2 5 0 . 2 9 1 0 . 0 3 :'a O . l 5 35.P �_i0 . 4 Z 2

s tee� reek;·/ gra ss forb : i . 86 2 0 . 02 ) 0 . 020 0 . 0005.p5.5.0 . 06 7

s , eec rock"}/ ponderosa p : ne 3 5� . .; I L S 0 . 2 9 : o . 3 1 9 0 . l 5 9.s_p65_0 . 4 ;; :

dogha ir O . l 4 2b ponderos a pine 1 56 . 4 0 0 0 . 000 0 . 000.5.p7.5.0 . 00C

Tot a ls i 1 0 4 . 0 5 86 - �- - - - ---- - - ---- - - - --- �--- - - - ---- - - - - - - - - - - - � - ----- --- ---------------- -a

b

: ndica �es select ion for a ha bitat type at the 0 . 0 5 s i gn i ficance l eve l . i ndica tes select ion aga inst a hab i ta t tn:e at t he 0 . 0 � s igni f icance leve l .

52

!at " e Al . Occurrence cf �abit a t occ�pat i on by the Grace Cool i dge ewe ��r� . . ;:: _s':er Seate i'ark. , SD, ! ro:n July tr.rough October , 1 98 5 .

Habitat Type

:r.: x�j gra ss / f =: r c

por::!erosa pine/ . . � ur.derstory

p-:.:.:!e rosa pine/ gr.:: S S forb

: : ;:arian

S : i!ep rocky/ 9rass forb

s :e-l?p rocky / F : r . .::erosa p i ne

cc;�.air p:�.:::erosa pine

TC': .l ls

Tota l Area ( ha I

1 e . , �

1 8 1 . 98

1 19 . � 2

1 7 . 90

6 . 20

2 ,: 4 . 09

1 09 . 7:,

5 3 5 . 800

No . Groups

Observed

1 2

1 0

9

6

0

l �

c 5 1

Actual Proporticn

of Usage ( Pi l

0 . 2 3 5

0 . 1 9 6

0 . 1 76

0 . 1 1 8

:i . ooo

::, . 2 7 5

� . 000

Expected Propor t ion

of Usage I P1o l

0 . 02 6 a

0 . 2 5 4

0 . 1 6 6

0 . 0 2 5

0 . 00 9

0 . 36 8

o . 1 s 3b

Bonferroni Interva ls

for Pi

0 . 076.s.P 1£0 . 39 5

0 . 0 4 7S.P2S.O . 3 4 6

0 . 0 3 l_iP3.i0 . 32C

0 . 000s_p4_5.0 . 2 3'?

0 . CCOs_p5.5.0 . ooc,

0 . 106s._p6s_0 . 4 4 3

O . OOOiP7£0 . 00C

: ndicates s election for a habitat type a t the 0 . 05 s ignif icance :eve.:. . :nd�cates se lect ion against a habitat type at t he 0 . 0 5 s igni ficance �e ·le l .

Table A4 . Occurrence of habit a t occupa tion by the southeast ram herd in Custer State Park. , SD , f rom July t hrough October , 1 98 5 .

H abitat: T'fPe

:r :. ;.:�d gra ss , f ::rl::

ponderosa pine/ r.o under story

pcnderos a pi_ne/ ; : ass forb

: ip .. r i an

Heep rock.JI gr a ss forb

s teep rocky/ ?Or.derosa pine

doghair i:onde rosa pi r:e

Totals

':'ot a l Area ( ha J

3 $ . 6 3

3 1 6 . 5 2

1 3 l . 0 7

:'> . 97

) 4 . 5 :

6 4 . H

4 7 . 7 3

4 !: u . 6 7 - - - - - --- � - ----- - - - - - - - - - -

No . Groups

Observed

2 0

0

2

5

0

H

Actual Proportion of Usage

I Pi l

0 . 08S

0 . 1 1 8

0 . :'>83

0 . 00:J

0 . 0 59

O . l fl

0 . 000

Expected P roport ion

of Us age ( Pio )

0 . 0 :1 6

0 . 4 9 8a

0 . 2 0 6b

o . oo g a

0 . 0 5 .;

0 . 1 0 1

o . 01sa

Bonferroni I nt erva l s

for Pi

0 . 000.5.p1.5.0 . 2 1 9

O . O OOs._p2_i0 . 26 6

0 . ) 6l.s_p3.5.0 . Bl 5

O . O OOs_p4i_0 . 000

O . O OOs_p5.5.0 . 1 6 7

0 . 000.5.p5s._O . J l �

o . o oo.5.p7.5.o . o : :

- - - - � - - ---- - --- - - - - - --- - - - - - - - - - ---- - - - --- -indicates select io!'l a;ains: a habitat tYJ;e a t the 0 . 0 5 sign i f icanc� leve l . i nd icates select ic� fer a hab i t a � t ype a t the O . O S s � gn i f �cance leve '. .

5 3

"." c :- :e h � . Occur :-ence o f habi t a t occupa ti c:: cy the so,ith.;e s t r am r.erd l ,. c� ; �e , S:ate Park , SD , f ro� July throJgh OCtobe r , 1 9 8 5 .

Ho:.i tat Type

:'f'li :·:c=. ;:-:tss /

fer::

;;o,.deros a pine/ . . _ 1.nde rs tcry

;:,c�.:lercsa pine / gr ass forb

:- 1 ;-.:! : : a n

s :!:C? rcc.i.;y/ ; !.' .i S S f c rb

st ce? reek:,· I ��:".:.e�osa pine

dcg�:a i r pondercs a pine

::ica l s

Total ll.rea ( ha )

6 1 . 3 4

1 9 6 . 57

3 3 8 . 97

S . 6 5

2 3 . 1 5

4 1 2 . 6 8

6 5 . 9 2

1 1 0 7 . 2 8

No . Groups

Observed

1

0

0

0

1 0

ll.ctual Proporti on

of Usage ( pi )

0 . � 00

0 . 300

0 , 100

0 . 000

0 . 000

o . �oc

0 . 000

Expected Propor ti on o f Usage

( Pi o )

0 . 0 5 5

0 . 1 7 8

0 . 3 0 6

o . o o 8 a

o . o :?l a

0 . 3 7 3

O . OGo a

Bon fer roni Interva l s for Pi

O . OCOiP1i0 . 3 5 5

O . OOOi.P2i0 , 69 0

O . OOOi_P3i0 . 35 5

O . OOOiP4iO . OO O

O . OCOiJ:>5iO . OO O

0 . 07 :' iPoi0 . 92 :i

O . OOOiP7iO , OO O

- - - - -- - - - -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - - - - - - - -

a indicates select ion aga�nst a habi tat t;-;:e at the 0 . 05 s ign i f icance '. e '.'E ? ,

,ajie A6 . occurrence o f ha b i ta t occupat ion for pooled ewe herds in Custer s : � :e Park , SD, f rom Ju ly through OCtobe r , 1 9 8 :i .

Ea::itat Type Tot a l ll.rea No . ( ha ) Groups

Observed

ll.ct·jal Propor t i on o f Jsage

( pi )

Expected Propo r t ion o f Usage

I Pio l

Bonferroni Interval s for Pi

w - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - · - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

r: .:. :·�ec <;r ! S S ,

!c::l:: 1 1 2 . 22

p: �.:ieros a pir.e / r - under s :ory 7 1 8 . 5 2

,-c r:derosa pine / I'.;: ;;. S S f c t"� 3 $0 . 46

:- : � i :· :. a n 7 1 . 95

; l €!'!P re::,:;· I t; :- i ii S fc:- ': 3 6 . 56

s -: ee;: ::eck:r.1 p::�.de ros a pine 7 3 .$ . 1 4

dogha i: pc�.de:-csa pine 2 78 . 8 3

Tc:. a l s 2 30 5 . 6 8

3 9

2 1

� � :, 3

6

6 6

0

209

0 . : 87 o . c � 9 a

0 . 1 00 0 . 3 1 2b

0 . 2 1 1 0 . 1 :i:t

0 . , 5 2 0 . 0 3.i. 8

0 . 1) 2 9 0 . 0 1 7

0 . 3 ! 6 0 . 3 1 9

0 . DC() o . 1 2 1 b

0 . 1 1 �.iP1iO . 2 5 9

0 . 0 4 5i.P2s.0 . 15 6

0 . l 3 5iJ:>3iO . 286

0 . 0 90iP �S.0 . 22 6

O . OOOiP5i0 . 060

0 . .2 29iJ:>6S.0 , 4 02

O . OOCiP7iO . OOO

- - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - - -

a r.d i ates se lec:ion for a habi t a t t '{pe a t the O . 05 s igni ficance ,e,ve

I: nd: a :es se lect ion a; a i�s t a habitat type a t the o . o ; s ign i f ica nce �J: �.-e

54

7ab :e A7 . Occurrence of hab �tat cccupa:ion for pooled ra, herds i n Custe: State Par k , SD , f rom July through October , 1 9 8 5 .

� !. >:0:: -;ra s s t ! o ::-;:;

por.de rosa pine/ no under story

pondercsa pine/ g ra ss for b

ripa r ian

steep rocky/ g ra ss forb

steep rocky/ pondercsa pine

dogha ir por.derosa pine

Tctals

Tota l Area ( h a l

96 . 9 7

5 1 3 . 0 9

4 7 0 . 0 4

H . 6 2

57 . 6 7

4 7 7 . 02

1 1 3 , 6 5

17 4 3 . 0 6

No . Groui:s

Observed

7

2 1

0

2

1 0

0

H

r\ctua l Proport ion of Us age

! Pi l

:-- . ·:, � 1

0 . 1 5 9

o . 4 7 7

0 . 000

o . o�s

o . :27

C . GOO

Expected Proport ion of Usa ge

( Pi o l

0 . 0 � 6

0 . 2 9 4

o . 2 1 o a

o . oos b

0 . 0 3 3

0 . 2 7 4

o . o es a

Bon f e r roni Interva ls

for Pi

O . OC 09 1�o . : (l7

0 . 0 1 19>2�0 . 3 0 7

0 . 2 75�P3i0 . 6 80

0 . 02 S9)4iO . OOO

0 . 0 00.1.Ps�O . U O

0 . 0 579>5i0 . 39 7

0 . 00097�0 . 000

- - - -- - - - - - --- - · - - - -- - - - - - - - - - - - - -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

ndica tes se lection for a �abi ta : type a t the O . OS sign i f icance eve l .

b r.dica tes selection a gainst a ha bita� t�-pe at the 0 . 0 5 s ignif icance eve 1 .

5 5

100

90

tiO

70

w 60 C> < 0:: w > 50 0 (.)

.... z w

-IU 0 "' w "-

::io

�o

Duff Forb Grass Hor i zontal Oensi ty

Rock

l'19ure Al . Mean ( + ;;e ) of grou11d cover , canopy cover , and horizout11l ..1.,n,;i ty for a ! l bi�horn .t.1h""P ra11ycs tor mixed 9nu,s/ forb h<ibi t at cy 1,c in Custer State Park, SD , 19HS .

S ei<:.t end ..:we herd , 8 Grae., Coo l idye ewe herd , Bsoucheast ram hc L'd,

[J :rnuthwe:.t r.lm herd , Qwes t ..;nd ewe herd .

:.hrul.l

l1l m

lUO

9 0

1::10

70

w 60

50

w .ao

w

30

.:o

I U

0

I I

� . I

; .

...i..:mi��,L......Llt.ll.,..l::ill"'--l..lLl�J.::,jjloL . ....J..J(.:L,..1..:i--1..l.�....L:l--.L.llui.-_Jl,l __ �--1·.-..-.

l:lare c,mopy Duff Forb Grass Hor izont "l Log Hock :,i,rub <: round Cover Density

tlgure A2 . Me"n ( + ¥v i of ground cover , canopy cover , dnd hor iz on tdl .:i.n.ity for all bighorn ¥h•oP r .. n.,,cs for l ipar ian hdb l t d t cyve in Cu.t..t ..:r �tate Par k , SD , 1 9 U 5 .

S e,u;. t c,nd ewe herd , 8 Gr<1ce

m sou thwc sc rdm herd , c .... ., s t

Cool 1..t._;, ewe herd ,

cud ..:we hcrd .

a ,iOUthedst rdlll he rel ,

U1 -.J

100

90

1:10

70

...... 60

50

-..,.. ..., 40 u (,:; w Q.

30

.!O

1 u

0 ;u.L...-.,..-,.__.J.l:illi�L£:il:JIY,llillU.._.Jllt:11f.1.ll:ilil.L.JJ:il'.:ir,.lli:ll.t....llL� Sar" Canopy Duff l,orb Grass Hori zontal Log kock

Ground cover Densi t y

Figure Al . M,:an I ! a� ) o f g round covci· , canopy cover , and horizontal a,mslty tor all bighorn a.ht:ep Lmqes tor Pondcrosct pine/no undcrstor y habi tat c.yp,: in Custer State Pd , � . sn . I :Ill!> .

S oect.!it t:nd ""'" herd, 8 Grae.,

fil southwt0st. rdlll h<'rd , Q we,.t end ewt0 herd .

Sl,ruL,

U1

(X)

100

90

i:10

70

w 60

50 0 u .... z ...., 40 u a::

30

20

1 0

0 Duff

I

�, """L.JJl.1.W::.u,Ji..u.;L--, . .i.....,_

l:ldt·e C,rnopy Ground Cover

Grdss Hor i zont .. l Dens ity

Forb Nock Log

l:'iqure A. .. . Mc .. u f ! lie ) of qround cover , c .. nopy cov«,: , .. nd hor i zont .. l <1cnlii i t y t or n l . bighorn i.heep 1·an>,1.: s for 1'011<:terosd pi.nc/c,Jrdss t o r b t,.t.bitdt type i , . i:'ust111r s t .. te Pdrk . SD , l 'i !:! S .

ned,;.t end ewe herd , g Grace Coo 1 1..i..,c ewe herd , D ,;ou thed s t '"'" herd ,

� sou thwl!:.t ram herd , Q west cud '-'""<.! herd .

:>hr ul..l

100

90

1:10

70

...... 60

!)O 0 0 ...

z ......

40 0 o::'. 41 Q.

::io

20

10

0 u .. re Canopy Duff Forb Crass Horizon tal Log Rock

(hound Cove r Density figure AS . Mean ( _! se ) of grounCl cove r , canopy cove r , and hori zont .. l ci.:n,;1 ty toe a l J bi<;horn i.htu.:1> 1 .. n\l"" f<ff steep rocky /ponClen:i .... pine i. .. bitd.t tYl •L· i n <'uster State p .. .- � . sn . 1 '111 ', .

8 cas t end ewe he rd, 8 Grace c..,o hdqe ew,: h,:rd , gsoucheds t r..m hero ,

m southwest rdln herd , Qwest end <,w,.: herd .

:.;hrul.>

O'I 0

100

90

BO

70

w 60

Q: w

> 50 0

0

...

z ....

40 u u: w a.

30

.::0

1 0

0

bare c,nopy Dutt For b Grass Hor i zontal Log kock Shrub Grvund Cover Density

r'igui:-c Ali . Mcdn (.! so l of ground cove r , Cdnopy cover , dnd hor ixont " l uons ity t o r .. 1 1 bignorn .,;h""I' ranye" t o r steep r:ocky/yr,,,::.s for b hdb l l ,H tyi• in Custer Stat:� Pdrk , SD . I Y H � .

S ..:.1st: end ewe herd, 8 Grd-:c: Coolidge ewe herd , Esout:Lcd::.l: Cd.o herd ,

gsouchwesc cam h<'rd, Qwc,- 1; end ewe herd .

0\

......

!:>UOUOO 1

400000

<

� 300000

� 0 ....... < .... 0:: < ..J 200000 <( Vl <( a:i

,00000

I-- S£ I-- SW � I-- wE -1

figure A7 . Mean I� se ) of tree bas a l area/ha for a ll bighorn sheep ranges for riparian habitat type in Custer Stat� Par k , SD , 1 9 8 5 . ££ eas t end ew..., herd , GC "' Gr .. .::e Coolidge e"'e he1·d , SE "' sou�hca::,;c 1·am herd , SW " ,.ou thw<.: i.. l 1·Am herd , w t: - west: end. e:"'e herd .

� Pinu,. ponderoiia � Quercu:,; m .. ccocarpd � bet:uld pap.iferou.,,

E\J Populus cremulo.ides � Mbce l laneous species .

AREA

0\ N

4( ::x:

700000

600000

500000

"''::::;, �00000 ::i (.) -

"' ..... � 2100000 ...J � Vl � £D

200000

100000

r-- EE --{ r-- GC --j !--- SE ----{ SW --j

Figure Ad . Medn ( + se ) of tree bu,a l area /ha for a l l b i ghor n shet1p r,mges t o r Ponde rosa p l ne7no unde rstory hab1t<lt type in Custer State P .. , K . SO , 1 9 8 5 . le:!:: = ca,-t end ewe tuird , G..: - Gr ,"�" Coo l idge ewe hte rd , SE = ,:;ou1 i.c.:. s t rum hc: rd , ::; w "' ,;ouc.hwest rl\m 1 1,,r,1 . w i:: " wt>st end cwt: herd .

� Pinus pond.cro•a � Quercus r.i<tcroc .. rpd ['.'.2:1 Bec.ula p<tpi fte.r ou:.

ES:! Popu lu .. t: 1 cmuloides � M 1 scc l l .111t:oui. £yc:cie.s. .

AHl: A

< :x: ' �

6000(J()

!:>00000

400000

� 300000 <( ..... IX <

_.. < Vl < 200000 £D

1 00000

r- t::E --f r- GC --f I-- SE -·-· J I-- SW

l'i,;iunt A'L M..:..in ( + !>c ) of t ree u<.1s.<1l <.1 rc.;./hd L ui' .. 11 bi9!1Qn1 :.l a,.;cp i·awJ..:;; fo1· Pomh:ros,, pJ.t1c/griis>1 tori.> h.it.i tat type.: .in t:u,,;t..:r :;c .. tc Pu.r k , :;u , l !l tl � . t:£ = C<ist end ,:\Jc ht!rd , GC = G.ritcu Cool idgc cwc hcL'd , S J:: = sout l,1.: ... :. t .ram ht:rd , SW " sout hwc,;t t•..in h<:!1'0 , WI:: "' 1,1-,,; c cm.I cwc he.rd .

� l:'1111.11o1 pond.:r..:: .. , � Quarcu:. 111<1c.coc .. rp<1 � tit'!tUl<i v"Pi f ll .Cc.1..,-

b::) Populus t rcmu loidcli

AHl: A

tioovuo

700000

600000

< 500000 :c ........

N-..

� £ 400000 ,c( w a: "" ...I

300000 "" VI ,c( a)

�00000

1 00000

'

t-- EE -"1 f-- GC -"j f-- SE -"1 f-- Sw -"1

F igure AlO . Mc,m I! se ) of t ree basal .. rca/ha for a l l bighorn :;h.:.:cp r .. ng..,,. for steep rocky/ponderosd pine habi tat type iu Custer State Park , SO, 1 98 5 . EE = ua:;t c11,l ewe herd , GC • i;r;;cc C,h1l idgc ewe h"1 d , !;f. = :.:outh<: ... ::. t r.,m he rd , SW = .;outhW!dlit rd.ll'I h,n a , Wt: " west end ewt: t ... : r d .

� Pinu11 ponderO&d � Quercus m .. croc .. rp.. [:'.2l lietula p .. pit erou,;

ESJ Popu lu .. t remuloi<.J.cs E:32 111sc.: ll aneou:; :.p..,.::ie:; .

O"\ U1

-< :I: -....... Ill ::i

401)

300

LJ 200 � Ill

0 z

100

I-- EE --j I-- GC --j I-- SE --j I-- SW --j f-- WE --j

Fi9ure Al l . Mean ( + se ) of number of t re., stems/ha for dll bighorn shccp rdnges for r i pd C ldn-habitat type in Cu� tcr State Pa r k , SD, 1 9 8 5 . ££ = c�st end ew� hc:: 1 ..! , GC -' Grdce Cool idg<· '"""' herd , : ;,.; = !>Ou ( l1cj:. t r....rn hc1·d , !;'.i .. .. .:.uchwe.s t ro1m r,..: n.1 , W£ ;: w�st end ewe herd .

� Pinus pondcros4 � Quercu.s rn ... ci::oc4rp" 22] uecul" p4pi tcrous

C'.J Populus t r cmulo1<les � Miscc l ldnf:ous specie;:. .

.t.AE.t.

.. ooo

3000

< :c ........ Vl

� w 2000 I-

I.II

0 z

1000

j- EE --1 j- GC --1 j- SE --1 j- SW --1 j- wE - j

Figure Al 2 . M..:an I + se ) of nwn!Jer of tree stems/ha tor a l l bighorn sheep r ange,; tor i'onderos;; pine/no unc.Jerstory ha.bitdt type in Cu,;ter St,lt . ..: l:',:.,· k , SIL l �HS . 1::l:: "' cctst end cw..: 1 ... : , <.1 , l.iC Gr:,<':c Cool idge <.:we tu..: rd , SI:: "' liOUtheast ram herd , SW = .:;out llw<.::..t r .:.m h,.;;riJ , Wt:: = we,; t cn<1 ewe h-, L"d .

[::§j l!inus s,ona.:roS4 � Quercus mctcroc.i.rp.. Z2l aet.ulc1 pdpifcrous

E:) Poi,ulus tremulo1des tZ1 Mi;;c1.d ldn<.:ous specioos .

AflfA

1200

< 900

' V)

:f: .... ...... Ill

ci :z 600

300

I-- £E --! I-- GC -I I-- SE --j

Figure Al l . Mo.,.in I ! se ) of m.uuJ;>c i:- of tn,c stems/ha foe a l l bigt,oen st ,.,cp r.sugci. foe l'ondceoi..s pine/gr .. .;:,; forb ha.bi tat type in Cus t.:r St.st" l'a e k , Sli , l9H5 . EE = , . ,, . , t end ewe h,:HI , GC " G , ,.,;., Cuo l idq,· ,::w" herd , St,; = sourh<:<1 :. t e ..,n h,:rd , S W . . southwest r am ho::,rd . W E "' wc :.r ,,11,1 ewe heed .

1.:1:J P1nua pon<J .. roa.a � Qucrcus ltl<lct·oc .. rp.. [::'.2l be tul..s i,.sp 1 t t:i ous

ES) Popu lu� trcmulo1des

AHEA

O"\ 00

2::.00

2000

< 1�00 ::r ......... II)

::.l w .... II)

ci :Z 1000

soo

f-- EE -f F igure Al 4 . Mc.:, n I ! ,;e ) of nwnbcc of cccc SC<.!ms /ha t oe ct l l bi ,i l,al !, ,m..:..:p t dngc:,; t o r :,;teeµ i:ocky/ponderosd pine/gc.;.s:,; forb habJ..c .. c t yf,c iu Cu�t<.: r :., t a t e h•.r k , SLJ , l 9 l:I � . EE = e " s t c 11d ""'' h..: rd , GC = Gr ct<:c Coo l i a,Jc cwi.: h..: 1 il , :c:i:: = .:.uuthcast t .lll\ he rd , SW = s,.,u r hw,, s t i·...i11 hc rd , WE ::. w ... s t cnd ewe 1,..: .-.:.t .

� Plnu,; ponde ro11.a � Oue rcu,; macroc .. rpa � B e t u l ii. p .. pif ., cou,.

£:SJ Popu lus t r emulo1des � Misce l l .. ncou:. spcci<..:s .

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