Stone Sheep and Their Habitat in the Northern Rocky Mountain Foothills of British Columbia
STONE SHEEP AND THEIR HABITAT IN THE NORTHERN ROCKY MOUNTAIN FOOTHILLS OF BRITISH COLUMBIA
by
ALAN JOHN LUCKHURST, B.Se.(Brit Col.)
A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REOUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN THE DEPARTMENT OF PLANT SCIENCE THE UNIVERSITY OF BRITISH COLUMBIA 1973
We accept this thesis as conforming to the required standard
THE UNIVERSITY OF BRITISH COLUMBIA
FEBRUARY 1973 In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British
Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the head of my department or his representative. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission.
Department of Plant Science The University of British Columbia Vancouver 8, B.C.
Date i
Abstract
Stone sheep (Oyis dalli stonei) and a representative, undisturbed habitat for this species were studied in the northern Rocky Mountain
Foothills from May 1969 through May 1971. A highly descriptive and holistic approach was taken in this introductory study, with physiography, soils, climate, and vegetation and the native sheep all being assessed.
The study was concerned primarily with the alpine sheep habitat with emphasis on the critical winter range.
Vegetation in this northern environment, reflecting physiographic, climatic and edaphic diversity, presents a.complex, heterogeneous pattern locally to a degree seldom observed in more southern latitudes. Local variations in climate, on different slopes and aspects, have produced striking floristic differences within short distances. Moreover, soils developed over different bedrock formations and distrubed little by glaciation contributed considerably to diversity in the alpine habitat.
Extremely acid soils characterized by impeded drainage and low temperatures limited forage production over much of the habitat. However, soils developed over calcareous parent materials on southern exposures had the favourable characteristics of moderately coarse texture, good drainage and an adequate nutrient status. These soils supported relatively productive plant communities and high quality forage for the sheep.
The vegetation was also characterized by stability especially in the alpine zone; this zone is largely free of a fire history and is characterized by climax or long-term disclimax communities. Apparent deteriorating climate over long periods may be very significant, however, because in all likelihood they reduce favourable sheep habitat. ii
Stone sheep were almost entirely dependent on the herbaceous alpine vegetation for their nutritional requirements. Even though plant succession proceeds slowly at these latitudes, serai grasslands tended to be invaded quite rapidly by shrubs which reduced the herbaceous cover and caused drifting snow to accumulate in winter. Grasses and sedges made up
95.6 percent of the winter diet and 78.5 percent of the fall diet of sheep collected in the Nevis Creek study area.
Vegetative diversity contributed largely to a balanced habitat for the sheep and the fortuitous combinations of factors of climate, soils and vegetation provided critical winter range on largely snow-free slopes with southern exposures. Three plant communities provided winter forage but one, the Elymus - Agropyron community, provided almost 60 percent of the forage utilized by wintering sheep. About 80 percent of the standing crop in this community, which made up only about 20 percent of the winter range and four percent of the total productive habitat by area, was utilized by the sheep. Although productivity was typically low in this alpine ecosystem, forage quality was relatively high and was maintained in the cured stage by hard fall frosts and the persistent winter cold.
Counts conducted in summer and winter over an extensive portion of the northern foothills and Rocky Mountains showed stone sheep populations averaged 35 percent mature ewes, 28 percent mature rams, 15 percent yearlings and 22 percent lambs (n = 981). Early summer counts for two seasons in the study area shewed an average ratio of 74 lambs per 100 ewes two years of age or older indicating a high birth rate and low mortality in the first few weeks of life. The lambs experienced almost 50 percent mortality by the end of their first year; however, most of it occurred early in the first winter. Classified counts of the ram segment of the population indicate a iii period of low mortality during adult life to age 8 or 10 years. Of course, intraspecific competition and malnutrition during severe winter conditions, disease and parasites, injury, predation and hunting all contributed to mortality to some degree.
Stone sheep populations reflect the stability of their relatively undisturbed alpine habitat. Actinomycosis and lungworm were common in sheep at Nevis Creek but there is no record of large-scale enzootic die- offs in this or other stone sheep populations such as occur in bighorn populations due to lungworm-pneumonia disease.
Stone sheep habitat, once remote, is rapidly becoming more accessible and subject to man's influence with development of the north. Interference in this northern environment by man must consider its sensitivity to abuse and its slew recovery. Any change or destruction of this northern sheep habitat, particularly the important and restricted elements such as the
Elymus - Agropyron plant community on the Nevis Creek winter range, would unquestionably seriously reduce the sheep populations dependent upon it. iv
TABLE OF CONTENTS Page
1. INTRODUCTION 1 1.1 Background 1 1.2 The Study 2 2. AREA DESCRIPTION AND DISCUSSION 3 2.1 Physiography and soils 3 2.2 Climate 4 2.3 Economy and land use 4 2.4 Flora 4 2.5 Fauna 5 2.6 The study area 6
3. PHYSIOGRAPHY, GEOLOGY AND SOILS 9 3.1 Background 9 3.2 Physiography 9 3.3 Geology 9 3.4 Soils 12 3.4.1. Soils below treeline 12 .3.4.2. Alpine soils 18 3.5. Discussion 23 4. CLIMATE 25 4.1 Methods 25 4.2 Observations and results 27 4.2.1. Air and soil temperatures 27 4.2.2. Precipitation and snow cover 31 4.2.3. Wind 33 4.3 Discussion 34 5. VEGETATION 39 5.1 Methods 39 5.1.1. Plant communities below treeline 39 5.1.2. Alpine plant communities 39 5.1.3. Importance of plant communities to sheep 40 5.1.4. Forage production and quality on the winter range 40 5.1.5. Forage utilization and wastage on the winter range 40 5.2 Observations and results " 41 5.2.1. Plant communities below treeline 41 (a) the Picea-Abies and north slope Picea-Abies communities 41 (b) the Populus community 45 (c) the Pinus-Salix community 46 (d) the Betula^Pinus and Betula-Abies communities 46 (e) the Betula-Salix community 47 (f) the Salix-Betula and Salix-Epilobium communities 47 (g) Valley meadow plant community 48 V
5.2.2. Alpine plant communities 48 (a) the Betula-Vaccinium uliginosum and Betula-Vaccinium yitis-idaia communities 48 (b) The Elymus-Agropyron community 50 (c) the Elymus-Festuca community 57 (d) the Dryas-Festuca community 59 (e) the Calamagrostis-Hierochloe community 59 (f) the Festuca-Dryas community 74 (g) the Silene-Calamagrostis community 75 (h) the Cryptogam-Salix community 75 5.2.3. Importance of plant communities to sheep 76 5.2.4. Forage production and quality on the winter range 77 (a) Productivity 77 (b) Forage quality 78 5.2.5. Forage utilization and wastage on the winter range 78 5.2.6. Discussion 80 6. STONE SHEEP 85 6.1 Methods 85 6.2 Results 85 6.2.1. Seasonal movements and distribution 86 6.2.2. Foods and minerals 87 6.2.3. Population structure .92 6.2.4. Productivity 96 6.2.5. Juvenile and adult mortality 99 6.2.6. Mortality factors 101 (a) competition for forage 101 (b) disease and parasites 102 (c) injury 104 (d) predation 104 (e) hunting 106 6.3. Discussion 106
7. GENERAL DISCUSSION AND CONCLUSIONS 113
8. LITERATURE CITED 118
9. APPENDICES' 123 Klan in pockef" LIST OF TABLES Table No. page
1 Some chemical and physical properties of forest and valley soils at Nevis Creek 19
2 Some chemical and physical properties of alpine soils at Nevis Creek 21 3 Mean and extreme monthly temperatures (°F) at the Nevis Creek valley station, 1970 28
4 Mean and extreme temperatures ( F) at Nevis Creek for the summer and winter of 1970/71 30 5 Precipitation totals at Nevis Creek and selected D.O.T. stations for the summer and winter of 1970/71 32
6 Mean wind velocities (miles per hour) during the winter of 1969/70 and the summer of 1970 at bothe Nevis Creek climatic stations and at two lowland stations 39 7 Padiation heat balance of selected surfaces at Nevis Creek on June 21, 1970 37
8 Plant communities studied below treeline at Nevis Creek 42
9 Relative abundance of major plants in classes 1-5 for four forest communities at Nevis Creek 43 10 Alpine plant communities at Nevis Creek 51 11a Major plant species coverage and frequency (C/F) for two sites in the Betula-Vaccinium uliginosium 53 lib Shrub measurements and ground surface components for two sites in the Betula-Vaccinium uliginosum community 54 12a Major plant species C/F for three sites in the Betula- Vaccinium vitis-idaea community 55 12b Shrub measurements and ground surface components for three sites in the Betula-Vaccinium vitis-idaea community 56 13a Major plant species C/F for three sites in the Elymus- Agropyron community 60 13b Shrub measurements and ground surface components for three sites in the Elymus-Agropyron community 61 14a Major plant species C/F for three sites in the Elymus- Festuca community vii
LIST OF FIGURES Figure No. page 1 Outline map of British Columbia shewing the location of the Nevis Creek study area 7 2 View of Nevis Mountain and alpine sheep ranges 8
3 Diagrammatic cross-section of the foothills ridge tentatively designated Nevis Mountain 9
4. A Gleyed Cumulic Regosol profile on an alluvial terrace 14
5 A Podsol profile under the Picea community 14
6 A Degraded Dystric Brunisol profile under open Pinus-Salix 15
7 A Chernozem-like profile developed in calcareous colluvium 16
8 A Degraded Eutric Brunisol profile developed in non- calcareous sandstone 16 9 A Lithic Degraded Dystric Brunisol profile on the windswept summit 17 10 Climatic station at 5500 feet (1675 m) elevation on the sheep winter range, Nevis Mountain 26 11 The north slope Picea community 49
12 The Betula-Vaccinium vitis-idaea community 49 13 The Elymus-Agropyron community 58
14 The Elymus-Festuca community 58
15 The Dryas-Festuca community on exposed ridge 66 16 The Calamagrostis-Hierochloe community 66 17 The cryptogam-Salix community . 71 18 Clipping grazed forage plots at site 10A in the Elymus- Agropyron community 83
19 A temporary exclosure at site 10A 83
20 Survivorship curve for stone rams in the northern Rocky Mountains 100 viii
APPENDICES No. page
1 Scientific and common names and authorities for plant species identified in the Nevis Creek area 123
2 Scientific and common names and authorities for mammals and birds mentioned in text 132
3 Some typical soil profiles and additional soils data 134
4 Miscellaneous climatic data and a list of instruments used 141 ACKNOWLEDGEMENTS
The field work of this project was financed by the B.C. Fish and Wildlife Branch and the Canada Land Inventory (B.C.). Office space, laboratory facilities and some technical services were provided by the Research Division, B.C. Fish and Wildlife Branch and the Department of Plant Science, University of British Columbia.
I am indebted to Dr. V.C. Brink, Department of Plant Science and to Dr. P.J. Bandy, B.C. Fish and Wildlife Branch, for directing this study. Dr. Ian McTaggart Cowan, Professor of Zoology and Dean of Graduate Studies, Dr. M. Tait, Assistant Professor, Department of Animal Science, Dr. A.J. Renney, Professor, Department of Plant Science and Dr. M. Taylor, Professor, Department of Zoology, gave invaluable assistance and advice, particularly during the preparation of the manuscript.
I am grateful for the cooperation and assistance of many members of . the Canada Land Inventory (B.C.) team: to Mr. D. Blower, project leader of the ungulate sector for permitting me to coordinate the field work of this study with my regular duties in northeastern B.C.; to Mr. J.R. Marshall, project leader, agroclimatology sector, for assistance in instrumentation and maintenance of climatic stations and the compilation of climatic data; also, to Mr. R. Muir, Mr. C.W. Tremblay and Mr. R. Reid for technical advice and services.
Mr. T.M. Lord, Pedologist, Canada Department of Agriculture, assisted in the field and made valuable contributions to the section on soils. To many members of the B.C. Fish and Wildlife Branch including Messrs. D.J. Robinson, Assistant Director, K. Sumamk, R.A. Demarchi, X
F.E. Harper and D.A. Demarchi, all'wildlife biologists, I am grateful for their encouragement and valuable advice.
Messrs. John Todd and Bob Marsh assisted greatly with the field work.
For their cheerful acceptance of an often lonely task and a minimum of physical comforts, I owe them much.
The field work was largely made possible and much more pleasant by the cooperation of Mr. Garry Vince and all members of the Wes Brown family of
Fort St. John. Their services and hospitality throughout the study are gratefully acknowledged.
To these people and many others who contributed in one way or another to this study, I am deeply indebted. 1
1. INTRODUCTION
1.1 Background
The native sheep of North America can be broadly divided into two groups, the bighorn (Ovis canadensis) in the south and the thinhorn (Oyis dalli) in the north. The stone or Stone's sheep (Ovis dalli stonei) is one of three races within the thinhorn group which inhabit an extensive area north of approximately latitude 56°N (Cowan, 1940). The stone sheep is the most abundant native sheep in British Columbia, and is second in abundance only to its subspecific cousin the white dall sheep (Ovis dalli dalli) in North America. Separated by less than a hundred miles from the northernmost bighorn group, stone sheep range extends northward into the Yukon Territory, but lies mostly in northern British Columbia, including much of the mountain• ous and high elevation plateau lands from the summit of the coast mountains to the eastern limits of the Rocky Mountain foothills.
The vast area inhabited by this native sheep is still largely remote and uninfluenced by man and there is little ecological information for any part of it. The only previous detailed studies on stone sheep in its native habitat were carried out by Dr. Valerius Geist in the Cassiar District of British Columbia and were concerned mainly with the social behaviour of this sheep.
In contrast to the northern regions inhabited by stone sheep, more southern latitudes of North America have experienced extensive ecological disturbance by man. As a result of man's influence, and particuarly his disturbance of their habitat, bighorn sheep have suffered serious population declines in recent years (Buechner, 1960 and Stelfox, 1971).
There is much concern now at the pace with which man is influencing his environment. The concern is heightened because it is now difficult or 2 impossible to reconstruct original conditions or to assess the ramifications of this disturbance. Moreover, there is little or no documentation from the past (Daubenmire, 1968).
Stressing the imminent need for serious study of natural communities,
Daubenmire (1968) points out that: "Soon the increasing demands of human populations will have put all the land surface under management and destroyed practically all natural ecosystems for eternity", and, ".. basic knowledge of the processes going on in undisturbed communities has much to offer in helping to manage the land for timber, game, forage, water and recreation".
1.2 The Study
In keeping with these views and in view of the rapid development of northern British Columbia, the objective of this study has been to describe a more or less representative and pristine section of northern sheep habitat, before it is materially altered. A highly descriptive and holistic approach was taken in this introductory study, with physiography, soils, climate, vegetation and the native sheep all being assessed, in some cases quite generally.
In addition to providing new information on the habitat and population dynamics of stone sheep in the northern foothills, the study is complementary to studies of bighorn and their habitat in southern British Columbia and to studies of dall sheep and their habitat presently underway in the Yukon and Northwest Territories.
Through my work with the Canada Land Inventory (B.C.), I was able to make observations over much of the northern Rocky Mountain foothills, which contain a major portion of the better stone sheep habitat, and to select a relatively accessible part of the area for this study. 3
2. AREA DESCRIPTION AND DISCUSSION
2.1 Physiography and Soils
The northern foothills parallel the Rocky Mountains in a belt fifteen to forty miles wide and more than 350 miles long from south of the Peace
River to the Liard River in northeastern British Columbia (Holland, 1964).
The underlying rocks, mainly of Mesozoic age, are greatly folded and faulted to produce a subdued mountainous topography characterized by a series of parallel mountain ridges. Relief and ruggedness vary, being generally greatest in the western half ; in the main, the summits are. about 2,500 feet (762 m) above the valley bottoms to reach elevations of about 6,500 feet (1,981 m). The longitudinal ridges are dissected by east-west through valleys which are generally wide and flaring as a result of glaciation.
Glaciation has been comparatively light as indicated by the thin mantle of glacial drift on valley floors, the absence of many glacial features and the close relationship of soil parent materials to underlying bedrock on mountain slopes.
Precise soil data are lacking for the foothills but Brunisols, Podsols,
Regosols and Gleysols appear to dominate while Chernozem-like soils have developed locally where parent materials and other site factors are favourable; organic soils occur on some poorly drained sites (Lord, pers. comm. 1972).
The dominant drainage is eastward and the foothills are characterized by a trellis pattern of drainage as streams make frequent right-angle turns to follow the northwest trending bedrock pattern (Holland, 1964). 4
2.2 Climate
That part of British Columbia which lies east of the Rocky Mountains
is dominated by Polar Continental and Polar Pacific air and experiences
long, cold winters and short, warm summers (Chapman, 1952), It has the
most continental climate of any part of the province with annual summer
temperatures occasionally in excess of 80°F (26.7°C) and temperatures below
-50°F (-45.6°C) for short periods during most winters.
Long term climatic data are lacking for the foothills. Here the
climate is modified somewhat from the prevailing climate of northeastern
B.C. as is illustrated in Section 4.
2.3 Economy and Land Use
With an economy based on agriculture, oil and natural gas, forestry
and tourism, settlement and development in northeastern British Columbia has proceeded at a rate well above the provincial average in recent years
(Department of Lands, Forests and Water Resources,' (B.C.) 1968). So far,
this activity has been limited mainly to the lowlands and, with the exception
of the Alaska Highway which crosses them west of Fort Nelson, no all-weather
roads occur in the foothills north of the Graham River.
Guided hunting parties have penetrated the foothills since the late
1920's and big game guiding is still the main land use and economic activity.
With the.abundance of game and limited access, the foothills area presently
supports some of the most successful big game guiding operations in the
province (Bowden and Pearse, 1968).
2.4 Flora
Two broad vegetation zones are recognized in the foothills, (a) the
Northern Foothills Section of the Boreal Forest Region, and, (b) Alpine
tundra (Rowe, 1959). 5
White spruce (Picea glauca) and alpine fir (Abies lasiocarpa) are the characteristic trees of the mature forest which has been largely replaced by serai lodgepole pine (Pinus contorta subsp. latifolia), willows
(Salix, spp.) and glandular birch (Betula glandulosa). Poplar (Populus balsamifera and P. tremuloides) dominate south facing slopes while grass sedge meadows with associated shrubs (Salix spp. and Betula glandulosa) occupy fine-textured alluvial soils in the valley bottoms.
Widespread fires have resulted in the replacement of much of the spruce-fir forest in the foothills by serai vegetation in recent times.
Both man-set and natural fires have been a factor here but it is difficult to assess their relative importance. In some parts of the foothills, man has maintained,by repeated burning, open plant associations favoured by wild ungulates and horses. Alpine vegetation is extensive above treeline which occurs at about 5,000 feet (1,524 m) altitude but extends to almost
6,000 feet (1,829 m) on protected slopes. Treeline is often poorly defined where serai shrub meets the alpine zone. Alpine meadows of grasses and sedges occupy higher elevations and exposed locations where climatic and soil factors are favourable while mosses and lichens prevail on cold northern exposures and stable rock surfaces.
2.5 Fauna
The prevalence of open plant associations and reduced snow cover in the northern foothills favours an abundant and varied vertebrate fauna.
In addition to stone sheep, moose (Alces alces) and caribou (Rangifer tarandus) are widespread and abundant while elk (Cervus canadensis), mule deer (Odocoileus hemionus) and mountain goat (Oreamnos americanus) are locally abundant. Large predators inhabiting the foothills include the black bear (Ursus americanus), wolf (Canis lupus), grizzly bear (Ursus 6
arctos), wolverine (Gulp luscus) and coyote (Canis latrans).
2.6 The Study Area
During the study, observations were made throughout most of the
foothills north of the Halfway River, but the main study area included
approximately 6,500 acres (2,630 ha) in the Nevis Creek area (see foldout
map). Within this, main interest focused on 1,300 acres (526 ha) of alpine habitat, on a typical foothills ridge tentatively designated Nevis Mountain
(Fig. 1). Located in the outer foothills, 30 miles (48 km) on the leeward
side of the Rocky Mountain crestline, Nevis Mountain rises to 6,675 feet
(2,034 m) from the valley bottom at about 4,000 feet (1,220 m) altitude
(Fig. 2). The valley contains a hunting camp and is traversed by a seismo•
graph road on which travel is limited mainly to the winter months. Except
for occasional travel through the valley and guided hunting, there has been little activity by man. Fire and the ranging of horses are the only
significant means through which man has influenced the native vegetation.
Although the vegetation below treeline has been materially altered by fire, the alpine vegetation, except in the shrub zone immediately above treeline, has been undisturbed by fire and has not been used by domestic livestock.
8
Figure 2. View of Nevis Mountain looking north. Alpine sheep winter range in the background. The Fopulus and Pinus- • Salix communities- on an old burn-are' seen' in the foreground.-- 9
3. PHYSIOGRAPHY, GEOLOGY AND SOILS 3.1 Background The physiography and geology of the study area are described from field observations, from the interpretation of air photos and from physiographic and geological reports (Lord and McLean, 1964, Holland, 1964, Pelletier, 1964, Pelletier and Stott, 1963, McLean and Kindle, 1951).
Soils were investigated at pits dug at one or more sites in each plant community. Soils were described and classified according to the guidelines of the Canada Soil Survey Committee (1970) as related by T.M. Lord, pedologist, Research Station, Canada Agriculture, Vancouver, B.C. Soil features recorded at each site included: drainage and nature of the parent material as well as horizon number, thickness, texture, structure and colour. Soil samples were analyzed at the Canada Agriculture Research Station, Vancouver, B.C.
3.2 Physiography The study area is physiographically varied, extending across a broad glaciated valley and including the southern two-thirds of 6,675 foot (2034m) Nevis Mountain. Nevis Mountain, a typical foothills mountain ridge, abuts the north side of the east-west trending valley. The upper portion of the valley is occupied by Nevis Creek which makes an abrupt turn northwards at the eastern end of the study area, to parallel, and thus largely contain, Nevis Mountain. Nevis Creek just north of the study area joins the Besa River. The broad valley, occupied in its upper reaches by Nevis Creek, continues eastward to completely penetrate the foothills, and meet the Alberta Plateau, some ten miles beyond Nevis Mountain. It is occupied in its outer reaches by the Buckinghorse River which flows east, across the plateau surface.
3.3 Geology
The floor and lower slopes of the through valley occupied by Nevis 10
Creek and the upper Buckinghorse River are covered by a thin mantle of glacial drift. The presence of granitic material from the Canadian Shield at the eastern edge of the study area indicates that continental ice sheets reached the area (W.H. Mathews, per. comm. (1971)). However, glacial erosion was mainly a result of ice moving eastward through the valleys and the glacial drift consists mostly of Palaeozoic limestone, chert and sandstone from the western mountains (Pelletier and Stott, 1963). North• westerly trending valleys such as the valley containing lower Nevis Creek were not eroded but did., receive a mantle of drift when the ice receded
(Holland, 1964).
Although valley bedrock is largely covered by glacial drift, rocks of the Buckinghorse Formation are exposed where Nevis Creek cuts deeply into them along the eastern edge of Nevis Mountain. These rocks consist mainly of acidic dark grey marine shales (Pelletier, 1964).
Glaciation has been light above treeline although limestone erratics, scattered sparsely to the summit of the mountain ridge, indicate complete ice cover from the west at some stage (W.H. Mathews, per. comm. (1971)).
The sedimentary rocks of the northwesterly dipping anticlinal ridge, designated as Nevis Mountain, can be described on the basis of
groups and individual stratigraphic units (Pelletier and Stott,
1963) (see Fig. 3). The Bullhead group of lower Cretaceous age and the
Schooler Creek group of Triassic age dominate. The younger Bullhead rocks which prevail on eastern and northern slopes are mainly siliceous sandstones, siltstones and shale of an acidic nature. Rocks of the Bullhead group have been largely eroded from the southern and southwestern slopes and from the peaks of Nevis Mountain, exposing the older rocks of the Fernie
Formation and Schooler Creek Group. The Fernie Formation is relatively thin, FIGURE 3 Diagrammatic cross-section of the Foothills ridge tentatively designated Nevis Mountain
Capping of Schooler Creek limestones on peaks
Scree and erosionol debris from Schooler Creek Group Scree and erosionol debris from and Bullhead Group Schooler Creek Group and Bullhead Group Bullhead Group
Bullhead Group-continuous on NW slope eroded from most of SW slope Buckinghorse Formation eroded to expose rocks of the Bullhead Group
Quaternary drift and colluvium -Stream Quaternary drift and colluvium Alluvial terrace Nevis Creek
Buckinghou.|__ formation Buckinghorse Formation
Strotiographic Units and Undivided Groups
f-'plj Buckinghorse Formation - mainly dark gray marine shales (Lower Cretaceous age) Bullhead Group - mainly siliceous marine sandstones and siltstone (mainly Lower Cretaceous age) Fernie Formation - less than 100feet thick-mainly rapidly weathering dark calcareous siltstone and shale with phosphatic chert (Jurassic age) Schooler Creek Group - mainly limestones, calcareous siltstones,shales and sandstones (Triassic age) 12 and little exposed here. It consists mainly of rapidly weathering dark calcareous siltstones and shale with phosphatic chert. The Schooler Creek group, several thousand feet in thickness, consists mainly of limestones and calcareous siltstones and shales. It includes strata which form massive limestone cliffs and ledges on the western slope and strata which contain numerous marine fossils including brachiopods (Halobia sp. and Monotis sp.), pelecypods (Gryphaea sp.), cephalopods (Ammonoidea sp.) and large marine vertebrates. 3.4 Soils
3.4.1. Soils below treeline
Soils below treeline have developed on alluvial, colluvial and glacial till deposits (Fig. 1). Selected chemical analysis of a Gleyed Cumulic Regosol occuring on recent alluvium are presented in Table 1 (site #16). This soil had 4 cm of Ah horizon over 11 cm of AGg horizon. These upper horizons overlie several stratified layers, including a buried Ah, which have a wide range in texture (Fig. 4). The pH values obtained show the soil is strongly acid in the surface horizons and pH increases to neutral with depth. The organic matter, total C and the C:H ratio are very high in the Ah horizon, and the organic matter content remains high in the subsoil horizons. Although the soil is imperfectly and poorly drained and occurs in a cold environment, it has a cation exchange capacity that is favourable for plant growth.
Podsols, Brunisols and Gleysols have developed on glacial till and colluvial deposits that cover most of the forested lower mountain slope. A mini-Humo-Ferric Podsol developed on glacial till (site #15) is characterized by a Bf horizon 10 cm thick which is overlain by a light coloured Ae 5 cm thick and an equal thickness of forest litter (Fig. 5). 13
The pH values shew that although the Ae and Bf horizons are extremely
acid, a horizon in which the reaction is mildly alkaline occurs at HO cm.
The high level of available phosphorus is related to the high total
phosphorus and is probably a mineral source at this lew pH (4.1). Organic matter is relatively low and the C.E.C. is only slightly lower than that
of the Cumulic Regosol. It is a moderately well-drained soil under a
closed forest canopy. Frost persisted in the subsoil until mid-summer.
For a more complete description of this and other characteristic soils in
the study area see Appendix 3.
A Degraded Dystric Brunisol has developed on well-drained slopes with
a serai Pinus-Salix cover.- A typical example of this soil is described at
site #12 (Table 1). It is characterized by a Bin horizon 30 cm thick
overlain by 20 cm of light-coloured Ae and a thin cover of forest litter.
The Bm horizon is low in organic matter (0.55%) and nitrogen (0.053%) and
the Ae horizon, which has only slightly higher values, has a high C:N ratio
(14.4). On drier sites with a more open canopy the Bm horizon is less
pronounced and the Ae horizon more weakly eluviated (Fig. 6).
Humic Gleysols have'developed on cold, northern exposures and are presently underlying thick moss-lichen layers and support an open canopied
Picea-Abies forest. A Humic Gleysol at site #17 had a fihric organic H horizon 10 cm thick with no noticeable eluvial or illuvial horizons (Table
1). Percent organic matter (45.72) and nitrogen (1.1319) are high, but
it is poorly drained with frozen subsoils and has an unfavourably high
C:N ratio (20.2).
Chernozem-like soils (see section 3.4), in contrast to Humic Gleysols
on cold northern exposures, have developed on steep southern exposures under moderately dense stands of small poplar (Populus tremuloides and P. balsamifera), Figure 4. A Gleyed Cumulic Regosol profile on an alluvial terrace. Note the predominantly fine-textured layers. Figure 6. A Degraded Dystric Brunisol profile under open Pinus-salix. Note the bunchgrass (Festuca scabrella) on this open canopied site. Figure 7. A Chernozem-like profile developed in calcareous colluvium. Note the depth of the Ah, the lower boundary of which is narked by the knife Iso the productive ground cover in which grasses predominate
Figure 8. A Degraded Eutric Brunisol profile developed in non-calcareous sandstone Figure 9. A Lithic Degraded Dystric Brunisol profile on the windswept summit. Note the shallowness of the profile and the sparse vegetative cover. 18 and dense lyme grass (Elymus innovatus). A black Chernozem-like soil at site Al is characterized by an Ah horizon 20 cm thick over a dark brown
Bm horizon 5 cm thick (Table 1). This soil, developed on calcareous marine sandstone, to a depth of 70 cm has physical and chemical properties favourable for plant growth. Results of the analysis show the Ah horizon to be high in organic matter (25.08%) and available nitrogen (1.134%) with a favourable cation exchange capacity (55.63 me/10Og). The C:N ratio of this well-drained sandy loam soil was found to be moderately high
(12.8) and the reaction was slightly acidic. The high reading for available phosphorus in the BC horizon may be related to the favourable pH of 6.8.
The soil described at site A2 has similar characteristics (Table 1).
3.4.2. Alpine Soils
Because there is very little glacial debris at higher altitudes, there is a close relationship: between alpine soils and the underlying sedimentary rocks from which they have developed.
Eutric Brunisols and Black soils are closely associated on the south . and west-facing slopes of Nevis Mountain. These soils have developed on neutral to slightly calcareous parent materials derived from rocks of the
Schooler Creek group. Black Chernozem-like soils were found on steep
(59 to 70%) southern exposures of the lower alpine slopes (Sites 10A,
10B and 10C). They were characterized by Ah horizons 10 to 20 cm thick.
A brown (7.5 YR 3/2m)* Bm horizon was present in all these soils and free lime was present in the lower B.C. of Cl horizons of the soils at sites 10A and
10C. (Fig. 7). These are well-drained loam soils that have developed to a depth of 70 cm or more. As the analysis results for site 10A indicate, these soils are high in organic matter and nitrogen and have a high cation Table 1., Some chemical properties of forest and valley soils at Nevis Creek
Site . Soil - Soil ' Horizon, Organic Organic '." N(%) =: C:N • CEC . Exchange Cations elev. Parent Order Matter(%) Carbon(%) ratio me/100g (me /lOOg)". " " (pp~ aspect . Material and • Ca K slope(%) Classif. •
16 Alluvium'' Regosolic Ah . 4.7 24.98 . 20.31 1.32 15. 55.63 29.29 0.64 31.2 4050(1234) Gleyed Comulic ACg . 4.4 6.19 0.32 19.68 8.57 0.09 31.5. Flat Regosol Cl 5.8. -if. 34 0.20 16.66 14.88 0.05 20.8 C2 7.2' 2.14 0.10 9.58 26.36 0.05 7.4
15 Glacial Podzolic Ae 3.1 1.06 0.63 0.05 10- 6.98 0.37 0.06 10.6 20.6 4200(1280) till Mini-Homo- Bf 4.1 1.79 1.03 0.08 -ll* 12.74 3.17 0.09 164.3 427.2 E Ferric Podzol BCk 7.5 1.27 0.06 5.51. 20.49 0.04 1.5 8.2 17 I •
12 Colluvium Br^tnisolic Ae 3.4 1.76 1.02 0.07 ilH. ' 5150(1559) Degraded Dystric . Bm 3.8 0.55 0.32 0.05 6. S Brunisol BC 4.4 0.17 0.03 ! 15
17 Colluvium Gleysolic 4525(1378) Humic Gleysol H 6.6 45.72 26.58 1.32 20. NE i 28 I-
Al Calcareous Black . Ah 6.2 25.08 14.55 1.13 12. , 55.63 51.29 0.37 30.3 120.6 4925(1494) Marine Chernozem-like Bm 6.3 9.03 0.42 12. 31.73 30.08 0.07 8.2 102.4 S Sandstone BC 6.8 5.30 0.30 10. 23.90 24.99 0.08 10.2 487.5 61
A2 Calcareous Black Ahe 5.5 22.11 12.13 1.05 11. 47.58 36.73 0.76 25.8 49 0 0(149 3) Marine Chernozem-like 5 Sandstone 70
" Available P. as determned by the Bray #2 method in appendix 20
exchange capacity and a favourable C:N ratio (Table 2).
A Lithic Humisol occurred at higher elevations on a steep southwest-
facing slope at site 3A. At this site, an H horizon 18 cm thick has developed directly on a calcareous C horizon and was overlain by an L-H horizon 2 to 3 cm thick. This soil, infused by basic seepage waters, is high in organic matter ( 39.83 percent),'has a high cation exchange
capacity (88.15 me/100 g.) and a moderately high C:N ratio (13.7).(Table 2).
In several respects this soil is similar to the Chernozem-like soils with which it is grouped here for descriptive purposes.
Eutric Brunisols were found on slightly acid to neutral parent materials derived from weathered rocks of the Schooler Creek group. These
soils, as shown for site ID, 2C and 2B in Table 2, have thin (5 to 12 cm),
grayish brown Ahe horizons and dark brown Bm horizons 15 to 21 cm thick
that overlie BC or C horizons in which free lime is generally absent (Fig.8).
They are slightly acidic with favourable texture and only moderately high
C:N ratios (Table 2).
Regosols and Degraded Dystric Brunisols occur on the east slope of
Nevis Mountain. These predominantly shallow, loam and sandy loam soils have developed on parent materials derived from acidic rocks of the Bullhead
group. They are very strongly to extremely acid (pH 4.8 to 3.5 in the
upper horizon) and well to imperfectly drained. A typical Lithic Dystric
Brunisol is characterized by a thin (5 cm), very dark grayish brown (10 YR
3/2 d) Ahe over a brown (10 YR 3/3-3/2 d) sandy loam Bm horizon (Fig. 9).
As indicated by the analysis results for sites 4B and IC respectively, the
Ah horizon is high in percent organic matter (20.65 and 12.14), low in
percent nitrogen (0.831 and 0.633) and has moderately high C:N ratios
(14.3 and 11.0) (Table 2). Table 2. Seme chemical properties of alpine soils at Nevis Creek
Site elev. Soil Soil Exchange Cations Aspect Parent Order & Organic Organic C:N C.E.C. (meg/ l00g) Slope Material Classif. Horizon Texture PH Matter(%) Carbon(%) N(%) ratio meg/1 OOg Ca ' K P (ppm)
10B Calcareous Lithic Black Ah L 6.0 17.86 10.36 0.96 11. 4990(1521)Sandstone Chernozem• BC L 6.4 4.78 2.7 0.26 10. S like 63
10A Calcareous Black Ah L 6.4 27.11 15.72 1.38 11. 61.75 55.99 .0.-44 9.5 101.7 5075(1546)Colluvium Chernozem• BC L 7.5 1.65 0.09 8.90 20.86 0.05 0.0 55.6 S like 3A Calcareous Lithic H SiL 6.8 39.83 22.55 1.65 14. 88.15 83.59 0.61 7.3 48.3 6100(1859)Colluvium Humisol SW 65 ID Neutral Brunisolic Bm L 5.7 5500(1676)Weathered Orthic Degraded Cl L 6.6 S Sandstone Eutric Brunisol 40 2C Neutral Brunisolic Ahe LS 6.0 27.97 16.41 1.17 14. 56 00 (17 07 leathered Lithic Degraded SW Sandstone Eutric Brunisol 26 2B Neutral Brunisolic Ahe LS 6.0 9.57 5.55 0.38 15, 5775(1759) Weathered Lithic Degraded Bm FSL 6.1 3.88 2.25 0.18 12. SW Sandstone Eutric Brunisol BC FSL 7.1 3.48 0.17 26 1C Acidic Brunisolic Ae FSL 4.8 12.14 7.0 0.63 11. 32.50 18.93 0.38 10.3 5450(1650)Sandstone Lithic Degraded Bm L 4.4 4.48 2.61 0.22 11. 20.46 9.06 0.13 7.1 SE Dystric Brunisol BC L 4.0 3.44 0.14 12. 11.64 3.95 0.10 6.8
,. . M Table 2. (continued)
5A Acidic Brunisolic Ahe SL 3.5 6000(1829Marine Gleyed Dystric Em SL 3.6 E Siltstone 16.,
4B Acidic Brunisolic Ahe L 3.5 20.65 11.96 0.83- 14. 33.35 4.87 0.16 33.5 41.1 6420(19 57)Quartzite Lithic Bm SL 3.6 2.74 1.60 0.1 '/ 11. 13.64 0.61 0.04 24.4 34.9 undulating 6 Dystric BC SL 3.7 2.79 0.12 11. 13.50 0.51 0.04 . 49.8 104.0 Sandstone Brunisol
* Available P by the Bray 2 method
ro ro 23
Humic Gleysols occurred both above and below treeline on slopes with a cold northern exposure., A Lithic Humic Gleysol described at site #17 below treeline is characterized by an H horizon, high in organic matter
(45.72 %) and nitrogen (1.319%) (Table 1). The C:N ratio was high in this
cold, poorly drained soil which had permafrost pockets in seepage sites.
The soil found above treeline on this cold exposure had similar charac• teristics .
3.4 Discussion
The study area is physiographically and geologically diverse. The
soils reflect this diversity, strikingly so in the case of alpine soils which were developed on parent materials derived directly from contrasting underlying bedrock formations.
Although lithic profiles are common, the alpine soils generally are characterized by loam or sandy loam textures, high carbon and nitrogen values and adequate levels of those plant nutrients tested for. Potassium
levels tended to be low but phosphorus levels are very high, due, in part, to the supply of inorganic phosphorus from sedimentary parent materials.
Eutric Brunisols and Black soils which prevail on southern and western exposures have the favourable characteristics of moderately coarse texture, good drainage and an adequate nutrient status, particularly the
Black soils which have developed under a very favourable microclimate.
The Black soils are classified as Chernozem-like soils because of possible temperature restrictions which, if applicable, would require that they be called Alpine Eutric Brunisols according to the Canadian system of soil classification (Lord, per. comm. (1972)). Terminology is based on a critical temperature of 0°C (32°F) and although a mean temperature of -2.5°C
(27.5°F) was recorded at the valley station in 1970, it is thought that 24 the soils in question developed in a microclimatic environment with a mean annual temperature in excess of 0°C (J.R. Marshall, per. comm.(1972)).
In contrast to the Black soils and Eutric Brunisols on southern exposures, Humic Gleysols containing frozen layers occurred on northern exposures and Dystric Brunisols and Regosols occurred on the high eastern slope and windswept ridges near the mountain top. In these latter soils on cool exposures, fertility is limited by low temperatures, saturated conditions and extreme acidity. Mottling and gleying are common, and C:N ratios are unfavourably high due to the slow breakdown of organic matter under lew soil temperatures, in these, and in fine textured alluvial soils in the valley bottom. 25
4. CLIMATE
Methods Two climatic stations were located in the study area in 1969, one in September at 4,050 feet (1234 M) altitude in the valley bottom and one in July at 5,500 feet (1675 M) altitude in the centre of the alpine winter range for sheep (Fig. 10). The location of these stations, which in future are referred to as the "valley" and "mountain" stations respectively, is shown on the fold-out map.
Since no long-term climatic records are available for the northern foothills, the stations were designed to measure general climatic parameters. Instrumentation at each of the climatic stations included a hygrothermograph and minimum thermometer housed in a Stevenson screen, two simple open rain gauges and an anemometer. In addition, a maximum thermometer and a six- month continuous recorder (which measured air temperature and precipitation) were located at the mountain station. Snow depth recording stakes, readable from the valley floor with binoculars, or from a low-flying aircraft, were located on the south-facing slopes of Nevis Mountain in two altitudinal transects from 5,100 to 5,250 feet (1555 to 1600 M) and from 5,450 to 5,500 feet (1661 to 1675 M). Soil thermistors which could be read with a
telethermometer were located 10 and 20 inches (25 and 50 cm) below the soil surface at both stations in May, 1970.
The mountain station was serviced once a week during the summer in 1969 and 1970 and the valley station was serviced once a month as far as was possible up to and including June, 1971. Snow cover was measured period• ically by reading levels on snow stakes located on the alpine winter range and by actual measure at ten random locations at the valley station.
In addition to providing the instrumentation for the stations, the 26
Figure 10. Climatic station at 5,500 feet (1675 M) elevation on the sheep winter range, Nevis Mountain 27 climatology sector of the Canada Land Inventory compiled and assisted in summarizing and interpreting climatic data. Where necessary, missing climatic data for Nevis Creek were interpolated using data from Canada
Department of Environment (formerly Department of Transport) meteorological stations at Fort St. John airport, Fort Nelson airport and Fort Nelson
Churchill mines (J.R. Marshall, 1970). Fort St. John airport at 2,775 feet
(844 M) altitude is located near Fort St. John on the Peace River lowlands
125 miles (201 km) southeast of Nevis Creek. Fort Nelson airport, at 1,230 foot
(375 M) altitude is located on the Fort Nelson lowland, 105 miles (168 km) northeast of Nevis Creek and Fort Nelson Churchill Mines at an altitude of
5,015 feet (1527 M) is located in the Rocky Mountains 105 miles (168 km) northwest of Nevis Creek.
4.2 Observations and Results
Considerable climatic data were lost due to malfunctioning or damaged instruments and servicing difficulties at Nevis Creek. However, a complete monthly record of air temperature was obtained for the valley station during the 1970 calendar year; the record permits direct comparison with standard data from other stations. Otherwise, the data presented are for the year, arbitrarily divided into a five month summer (May 1 to September 30) and seven month winter (October 1 to April 30) for which the most complete seasonal records were obtained. Additional climatic data and a complete list and description of climatic equipment used are included in Appendix 4.
4.2.1. Air and soil tanperatures
In 1970, the valley station had an annual mean daily temperature of
27.5°F (-2.5°C), a mean maximum of 39°F (3.9°C) and a mean minimum of 14.4°F
(-9.8°C). An extreme maximum of 81.0°F (27.2°C) was recorded in August and a minimum of -49.9°F (-45.5°C) in January (Table 3). The mean daily temperature exceeded 32°F (0°C) for five months from May to September, but 28
Table 3. Mean and extreme monthly temperatures (°F) at the Nevis Valley Station, 1970
Month Mean Period Mean Period Mean Maximum Maximum Minimum Minimum Daily
January *(8.9) (35.1) (-14.1) -49.9 ((-2.6) February 29.9 41.1 6.6 -21.0 18.4 March 30.8 40.4 6.9 -10.4 18.9 April 41.2 50.1 16.4 -5.0 28.8 May (55.0) 69.6 (32.0) (21.8) (43.0) June 62.5 79.6 35.8 26.5 49.2 July 62.3 74.8 35.4 25.0 48.9 August 63.3 81.0 35.5 24.5 49.4 September 52.4 66.0 29.4 9.0 40.9 October (42.2) 59.9 (21.4) 2.0 31.7 November (11.8) 43.3 (-2.5) -30.6 4.6 December (7.3) 39.1 (-9.0) -32.0 -0.9 Mean Annual 39.0 14.4 27.5
" Brackets indicate values which have been determined, at least in part, by interpolation 29 several degrees of frost were recorded during every month of the year in
1970.
The mean and extreme temperatures for the summer and winter periods of 1970/71 are shown for both stations at Nevis Creek in Table 4. Daily mean temperatures were comparable for the two stations during the summer months. However, the mountain station had a smaller mean diurnal range of temperatures with a mean maximum averaging 6.0°F lower and a mean minimum
4.7°F higher than the valley station. Higher minimum temperatures resulted
in a mean minimum above 32°F (0°C) for all five summer months at the mountain
station as opposed to only 3 months at the valley station. While seven or eight degrees of frost were recorded at the valley station in July and
August, only one degree of frost was recorded during these months at the mountain station. Department of Transport records (1970) show that mean daily temperatures exceeded 32°F for seven months from April to October and that the months of June, July and August were frost-free at the lowland
stations of Fort Nelson and Fort St. John airports.
During the winter months, a mean daily temperature of 12°F was recorded
at the valley station. Records were obtained for only three winter months
at the mountain station when mean maximum temperatures averaged slightly higher and mean minimum temperature several degrees lower than at the valley
station. Rapid and substantial temperature changes occurred in winter and
temperature inversions resulted in differences of 40°F or more between the
valley bottoms and mountain slopes on occasion.
The limited record obtained during 1970 indicates that well-drained
soils at the valley station had thawed to a depth of 20 inches by the end
of the first week in May. Moderately well-drained soils at the mountain
station remained frozen at this depth for another month. However, a
temperature of 35. 5°F (1.9°C) was recorded in well-drained soils adjacent TABLE 4. Mean and extreme temperatures ( F) at Nevis Creek for the summer and winter of 1970/71
Valley Station Mountain Station Mean Extreme Mean Extreme Mean Mean Extreme Mean Extreme Mean max. max. min. min. daily max. max. min. min. daily
May ^ (55.0) 69.6 32.0 (21.8) 43.0 47.4 56.9 34.1 22.5 40.9
June 62.5 79.6 35.8 26.5 49.2 56.7 74.1 41.0 28.5 48.9
July 62.3 74.8 35.4 25.0 48.9 56.8 71.8 42.0 31.0 49.4
August 63.3 81.0 35.5 24.5 49.4 55.7 76.9 40.1 31.0 47.9
September 52.4 66.0 29.4 9.0 40.9 49.2 61.8 34.2 18.3 41.7
Av. Mean Summer 59.1 33.6 46.3 53.1 38.3 45.8
October (42.4) 59.9 (21.4) 2.0 (31,7) missing missing missing missing missing
November (11.8) (43.3) (-2.5) (-30.6) (4.6) missing missing missing missing missing
December (7.3) (39.1) (-9.0) (-32.0) (-0.9) missing missing missing missing missing
January 5.4 38.2 -19.5 -48.0 -6.6 -1.1 35.0 -19.7 -49.0 -10.4
February 25.7 43.9 0.6 -25.9 13.2 missing missing missing missing missing
March 24.4 39.6 -0.9 -26.0 11.7 17.4 30.0 2.5 -15.3 10.0
April 41.2 60.3 19.6 -11.0 30.4 (33.0) (51.7) (19.2) (-2.8) (26.1)
Av. Mean Winter 22.6 ' 1.2 ' 12.0 missing missing missing 1 00 Brackets indicate interpolated values ° 31 to the mountain station on June 2nd and alpine soils on a 60 percent slope with a southern exposure had thawed to a depth of at least 20 inches by May
14. Soils on steep southern exposures probably thawed much sooner than soils in the valley bottom. In contrast, alpine and forest soils on a northern exposure still had frozen layers within twenty inches of the surface two months after the summer soltice.
It should be pointed out that soil thermistors at the valley station were located in coarse gravels as opposed to those at the mountain station which were located in fine to medium textured loams. Unfortunately no temperatures were recorded in fine-textured alluvial soils which prevailed in the valley bottom. Much lower soil temperatures would be expected in the fine textured alluvial than in the gravelly soils in which the thermistors were located at the valley station. Soil temperatures at the 2o inch depth averaged 49.2°F (9.4°C) at the valley station and 38.0°F
(3.3°C).at the mountain station during June, July and August.
Soil temperatures had dropped to 40°F (4.y4°C) from a high of 44°F
(6.6°C) by August 29 at the mountain station and had dropped to the same level from a high of 56°F (13.3°C) by September 13 at the valley station.
Ambient air temperatures indicate that they would have been frozen by
September 15 at the valley station and by September 20 or possibly as early as September 11, at the mountain station.
4.2.2. Precipitation and snow cover
Precipitation totals for the summer and winter seasons of 1970/1 at
Nevis Creek and other selected stations are shown in Table 5.
Summer precipitation totals at the valley and mountain stations were similar. Most of this precipitation fell as rain, but snow occurred in
May, August and September. 32
During the winter of 1970/71, the mountain station received approximately 5.70 inches (12.7 cm) of precipitation for a total of
18.10 inches (46 cm) during the year beginning May 1, 1970.
In winter, precipitation falls as snow which covers the ground unevenly because of different exposure to sun and wind. To illustrate:
During the last two weeks of January, 1969, the northern foothills experienced clear, cold weather with little wind and the valleys and mountain slopes had a continuous snow cover of about 10 to 18 inches
(25.4 to 45.7 cm). Three weeks later, after a period of milder weather, with many windy days, almost two feet (30.5 cm) of snow lay in the valley bottoms while many exposed slopes and ridges were completely snow-free.
A transect from valley bottom, at 4,350 feet (1,326 M) altitude, to the lower alpine slopes of a foothills ridge in late February, 1969, showed the snow cover averaged 21.8 inches (55.4 cm) and varied from 20 to 22 inches
(51 to 56 cm) in the valley bottom which supported a scattered cover of low-growing Salix spp. On slopes of 38 to 66 percent with a southern aspect, snow depths averaged 14.7 inches (37.3 cm) and varied from 13.5 to 16.0 (34.3 to 40.6cm) inches under a moderate cover of Populus spp.
Above 5,000 feet (1524 M) altitude on alpine slopes of 50 to 80 percent with a southern exposure, snow depths ranged from 0 to 22 inches (0 to
56 cm) depending on exposure to wind.
In the valley bottoms at Nevis Creek, a more or less continuous snow cover persists from early November until late April (Garry Vince, per. comm.
1970). Winter snow depths averaged 8 inches (20.3 cm),at the valley station in 1969/70 and 9.1 inches in 1970/71. The maximum recorded snow depth was three feet ( .91 m ) and included some snow which had accumulated through drifting. During the winter of 1970/71, snow depths averaged only 32(b)
Table 5. Precipitation totals at Nevis Creek and selected D.O.T.* stations for the summer and winter of 1970/71
Station Summer Winter Annual (inches) (inches) (inches)
Nevis Valley 11.98 missing missing
Nevis Mountain 12.40 5.70** 18.10**
Fort St. John A 8.46 7.81 16.27
Fort Nelson A 11.65 5.36 17.01 Fort Nelson 22.48 11.00 33.48 Churchill Mines
* Department of Transport (now Department of Environment) ** Approximate 33
3 or 4 inches (8 or 10 cm) on the exposed south-facing slopes of Nevis
Mountain. Drifts in excess of three feet occurred but snow-free areas were common on exposed sites. By the end of the first week in
May, only occasional patches of drifted snow remained on southern and western exposed alpine slopes while northern and eastern exposures had a continuous cover until late May or early June. Alpine slopes with a southern or western exposure had less than a month of continuous snow cover during the entire winter of 1970/71 (Garry Vince, per. comm. 1970).
4.2.3. Wind
Mean wind velocities at the mountain station were more than double those at the valley station in 1969/70. Mean wind velocities recorded at Nevis Creek and at two lowland stations (D.O.T. 1970) during the winter of 1968/70 and the summer of 1970 are shown in Table 6. Table 6. Mean wind velocities (miles per hour) recorded the winter of 1969/70 and the summer of 1970 at both Nevis Creek climatic stations and two lowland stations
Station Winter Summer Mean Annual
Nevis Valley 4.5 3.8 4.2
Nevis Mountain 10.2 8.6 9.5 Fort Nelson A 4.0 4.8 4.4
Fort St. John A 8.5 8.6 8.6
During the summer, periods with no measurable wind were few and brief at the mountain station. The highest mean velocities were recorded during the first week in July (19 m.p.h.) (30.6 km.p.h.) and during the two weeks in mid-August (16.5 m.p.h. (26 km.p.h.), but 34 moderately high velocities were also recorded in early summer from May
11 to June 26 (12.2 m.p.h.) (19.6 km.p.h.). Higher wind velocities were recorded at both stations for the winter than for the summer period, even though the winter is characterized by periods of calm or relatively light winds.
4.3 Discussion
A description of the climate and its role in the ecology of the study area is limited by the short, two-year period for which climatic data were gathered and by a lack of microclimatic data.
In general, the climate fits the description of Chapman (1952) for northeastern British Columbia with variations due to local relief and the proximity of the mountains. The influence of local relief was reflected in cooler mean ambient air temperatures (see Table 4 and
Appendix 2), and slightly higher precipitation totals (see Table 5), especially at the mountain station, than at lowland stations east of the foothills.
Long term records (Department of Transport, 1967 and 1968) indicate that mean temperatures and frost-free periods at Fort Nelson and Fort St. John differed little in 1970 from the long-term climatic normals.
The degree of continental!ty, as measured by the mean diurnal temperature range, was greater at the valley station and smaller at the mountain station in 1970 than at the lowland stations east of the foothills. During the summer, skies over the foothills were often overcast during at least part of the day due to moist Pacific air invading from the west. A variety of orographic clouds formed on the crest, while lanes of clear sky marked the troughs of airflow waves in 35
the lee of the Rocky Mountains.
Sudden and often violent local storms were a common feature during the summer. Winds of medium velocity were broken only briefly by periods of calm or by sudden gusts during local storms.
In winter, more stable polar continental air dominates northeastern
British Columbia and the cold northern skies are more frequently clear (Chapman, 1952). In the foothills area, periods of cold with relatively calm winds were broken by periodic invasions of warmer
Pacific air which brought strong winds. The winds descending in the
lee of the Rocky Mountains were probably further warmed adiabatically contributing to rapid and substantial temperature changes observed during such times. The winds funnelled down the broad valleys which penetrate the foothills and caused a rapid reduction in snow cover on
exposed slopes.
Maximum wind velocities were not measured during the study but high winds were experienced on several occasions. In December, 1969,: both climatic stations were damaged by winds, with an estimated average
speed in excess of 70 miles per hour (112.7 km.p.h.) and gusts that
approached or exceeded 100 miles per hour (170 km.p.h.) (Garry Vince,
pers. comm.). This contrasts with maximum observed hourly speeds of 40
and 55 miles per hour (64.4 and 88.5 km. p.h.) and probable maximum
gust speeds of 57 and 72 miles per hour (92 and 116 km.p.h.) recorded
at Fort Nelson and Fort St. John stations respectively during the twelve- year period from 1955 to 1966 (Canada Department of Transport, 1968).
Although no attempt was made to measure microclimatic parameters
during this general study,- the climate near the ground varied greatly within the study area. The important influence of slope and aspect was 36 indicated by the presence of frozen layers within twenty inches (50 cm) of the soil surface of a northern exposure while soils of a steep southern exposure were thawed to that depth by early spring.
To demonstrate the influence of insolation, the total heat balance received due to solar energy by surfaces of different slopes and aspects at Nevis Mountain on June 21, 1970, are shown in Table 7.
The calculations are based on the following equation:
(I + i) (1.' - °0 -R^ = R where I represents direct short wave radiation, i represents diffuse short wave radiation, <* represents the albedo, represents incoming long wave radiation and R represents the net radiation heat balance (Wang, 1963). The equation was calculated using the mean ambient air temperature recorded at the valley station during the 18 hour period between sunrise and sunset and assuming completely clear skies and a herbaceous ground cover with an albedo of .82 calories per square centimeter per day.
Table 7. Radiation heat balance of selected surfaces at Nevis Creek on June 21, 1970
Surface Slope Calories per square centimeter per day Exposure Radiation heat balance
South Horizontal 458
South 45 percent 467 West 45 percent 385 East 45 percent 383
North 45 percent 200
North 110 percent 40
As shown in Table 7 the net energy received by a slope of 45 percent with a southern aspect is almost 2 1/2 times that received by 37 a surface with the same slope and a northern aspect and almost twelve times that received by a 110 percent slope with a northern aspect. Over the growing season the radiation heat balance received by steep south-facing slopes would be significantly greater than that received by flat surfaces or north and east-facing slopes.
The influence of microclimate was also shown by striking differences in the floristics and net productivity of plant communities in the study area as discussed in Section 5.
Although specific climatic requirements and limitations of range plants are unknown for the study area, they have been investigated elsewhere. Conrad (1950) has suggested that a mean daily temperature of ^2°F (5.5°C) is satisfactory for the growth of many perennial plants and Harper (1961) found that continuous spring growth of range plants in the Ashnola area of British Columbia commenced when the mean temperature rose to this level. Harper '(1961) found that growth was terminated by a moisture deficiency in mid-summer and that the short growing season was a main factor limiting net productivity on the
Ashnola ranges.
The ^2°Y threshhold is very near the peak of the mean monthly temperature curve at Nevis Creek during the growing season. Also, mean daily temperatures generally fluctuated quite widely about the monthly mean with minimum temperatures frequently dropping below freezing level. In fact, the frost free period was only nine days in duration at the valley station and sixteen days in duration at the mountain station in 1970. In view of the mean daily temperature range and the high incidence of frost, during the growing season at Nevis
Creek, it does not appear meaningful to apply the usual standards for 38 measuring growing season to the growth of native plants in this area.
Soils on most sites were still frozen some time after the date at which mean daily temperatures reached the 42°? threshold. In addition to being able to withstand several degrees of frost, seme species are capable of growth when soil temperatures are at or near freezing level and early emergence may occur due to soil surface wanning while subsoils are still frozen. For most herbaceous plants, however, the surface onset of continuous spring growth probably depends on/soil temperatures reaching a threshold value somewhat above 32°F (0°C). The growing season is short and while growth may be terminated by a moisture deficiency on some dry sites, on most sites it appears to be terminated by severe frost in late summer or early fall. 39
5. VEGETATION 5.1 Methods
Plant communities were delineated and sites selected for study following the interpretation of 20 chain (1:15,840) air photos and ground reconnaissance (Lord, T.M. and A. McLean, 1969). A cover type map was compiled on a 40 chain (1:31,680) topographic base with correction for slope and photo distortion (see foldout map). Plant communities which were too small, or too poorly defined to map individually,were symbolized on the cover map in complex with the symbol for the major community with which they were associated. The area occupied by plant communities was determined with a compensating polar planimeter.
5.1.1. Plant Communities Below Treeline
Plant Communities below treeline were broadly defined and were studied only briefly using general transects and a simple system of rating species by abundance ocularly because sheep do not use them to any extent. Trees were aged by counting the annual rings at a 2 foot (61 cm) stump height except in the Populus community where they were aged at a 4 inch (10 cm) stump height. The Populus community was studied using four fifteen meter transects in a straight line sequence equidistantly spaced. Tree ages, number per unit area, height and diameter at 4.5 feet
(1.14 m) were determined by measuring all trees in three randomly selected
1. by 3 meter belt plots along each vegetation transect.
5.1.2. Alpine Plant Communities
Alpine plant communities on which the sheep depended almost exclusively were studied and described in greater detail than communities below treeline.
A quantitative macroplot method for the description and classification of range vegetation (Poulton and Tisdale, 1961) was used with some modifications 40
in the study of alpine vegetation. Modifications included the use of a
one meter, rather than a four foot belt along the 15 meter transect line.
Also, average shrub heights and crown diameters were determined by measuring
all shrubs in one by three meter belts along each transect line. The
foliage intercept of shrubs was measured along each transect line in those
communities where shrubs were a major species. The canopy coverage method
of vegetational analysis (Daubenmire, 1959) was used to determine species
percent cover and frequency and to measure ground surface components within
each macroplot. Ten locations were studied at 1.5 meter intervals along
each 15 meter transect line using the one tenth square meter observation
frame described by Daubenrnire.
On areas too small for more detailed study, paired 15 meter transects were used instead of a macroplot. One to four sites were studied in each community, depending on its size and variability. 5.1.3. Importance of Plant Communities to Sheep The importance of plant communities to sheep was determined from aerial and ground observations, discussions with guides and prospectors familiar with the area and by counting all pellet groups within the 1 by 15 meter vegetation transects. Pellet groups were counted if at least half the group lay within the transects.
5.1.4. Forage Production and Quality on the Sheep Winter Range A measure of primary productivity and forage available for wintering sheep was determined by clipping and weighing the herbaceous cover on 127 replicated yield plots from 10 study sites in the three major plant communities on the winter range. The pre-clipped yield plots, protected from grazing animals by fencing, were clipped to one half inch above ground level and
the vegetation removed was oven dried to constant weight at 105° C.
A measure of forage quality was obtained by determining total nitrogen 41 from milled samples of pooled forage from the 1970 fall yield and spring utilization plots (see Section 5.1.5) using the macro Kjeldahl method
(Association of Agricultural Chemists, 1960). Percent riitrogen was multiplied by 6.25 to obtain crude protein estimates. The overwinter decline in crude protein was represented by the difference in crude protein content of forage from the fall yield plots and weathered forage from the spring utilization plots.
5.1.5. Forage utilization and Wastage on the Winter Range
Forage removed by overwinter grazing and wastage from the three principal plant communities on the winter range was represented by the difference in oven-dried forage weights from fenced yield plots and 108 replicated utilization plots established adjacent to the fenced enclosures. The utilization plots were clipped to one half inch above ground level before new growth began in the spring. Overwinter loss, due to weathering, was represented by the differences in forage weights from ungrazed plots clipped in the spring and replicated plots clipped the previous fall.
5.2 Observations and Results
5.2.1. Plant coninunities below treeline
Plant communities defined and described below treeline occupied about
5,200 acres (2,104 ha) including six communities in which forest trees were major species, three in which shrubs were major species and one in which grasses, sedges and forbs were predominant. They are listed, with descriptive features, in Table 8. A list of major plant species occurred in four of the forest communities is shown in Table 9.
(a) The Picea-Abies and north slope Picea-Abies communities
The Picea-Abies plant community represents the mature boreal forest vegetation which would occupy most of the area below treeline, or about 42
Table 8. Plant communities studied below treeline in the Nevis Creek area
Plant Site Elevation Slope Aspect Soil Area acres Cammunity No. feet(metres) (%) Order (hectares)
A. Forest:
Picea-Abies 15 4200(1280) 28 E Podsolic
(P^r- North slope Picea-Abies 18 4525(1378) 28 NE Gleysolic 1400(567) cry"
Pinus-Saliix(F2) 14 4450(1355) 30 W Brunisolic 2704(1904) 5150(1559) 15 Betula-Pinus (F?) 13 E Brunisolic 168(68)
Betula-Abies (F^) * 4800-5500 25-70 (NW-E) Brunisolic 40 (16) (1462-1675)
Populus (A) A.^ and 4925(1494) 60 S Brunisolic 220(89)
A2 4900(1493) 70 S Brunisolic B. Shrub:
Salix-Epilobium * 3950-4250 0 - Regosolic 222(90) TBT^— (1203-1294)
Salix-Betula (T) * 3950-4250 0 Regosolic 220 (89) (1203-1294)
Betula-Salix (S2) * variable variable variable Regosolic - C. Grassland:
Valley meadow (G_) 16 4050(1234) 0 Regosolic 64 (26)
"Bracketed symbols correspond to symbols used in cover map
Reconnaissance only. Altitudinal ranges and soil types are tentative 43
Table 9. Relative abundance of major plants given in five classes (A -E ) for four forest communities in the Nevis Creek area
Species Picea Pinus-Salix Betula-Pinus Betula-Abies TF^T TFJ5 CFJ5 CT45 "
A. Trees: Picea glauca 4 1 XI Abies lasiocarpa IX 13 Pinus contorta 3 2 subsp.latifolia Populus spp. 1 X
B. Shrubs:
Betula glandulosa 1 2 5 5 Salix spp.1 13 14 Vaccinium uliginosum XI 13 Vaccinium vitis-idaea 13 2 3 Arctostaphylos uva-ursi 1 2 1 Empetrum nigrum X 11 Ledum groenlandicum XI XI Juniperus communis 1 11 Shepherdia canadensis 1 Rosa acicularis 1
C. Forbs: Linnaea borealis XI XI Potentilla spp. XXI Epilobium angustifolium 1 XX Saxifraga tricuspidata 1 X Cornus canadensis XI XX Lupinus arcticus 1 Artemisia norvegica 1
D. Grasses: Festuca scabrella X 2 XX Other species^ XI 11 44
Table 9. (cont'd).
Species Picea Pinus-Salix Betula-Pinus Betula-Abies (F ) (F ) 2 3 Indicates the species occurs commonly but has been assigned an_. abundance rating less than one. Species not having an abundance rating of one or more for at least one community are not listed here. mainly Salix glauca but S. scouleriana, S. myrtillifolia, S_. subcoerulea and S_. alaxensis are common associates and S_. lanata occurs in F^. mainly Poa spp., Calamagrostis lapponica and Elymus innovatus Identified by Dr. W. Scholfield; specimens lodged in the University of B.C. herbarium 45 5,000 feet altitude in climax or near climax condition. Only remnant stands of this forest community remained in the study area because of widespread fires in the recent past. In remnant forest stands 150 to 200 years in age, white spruce (Picea glauca) was the dominant species and Abies lasiocarpa, a common associate which increased in relative abundance with elevation. The forest understory was characterized by a moderate to sparse layer consisting mainly of Salix spp. and Betula glandulosa and a ground cover dominated by mosses and lichens (see Table 9). Mature forest vegetation was supported by Pcdsols except on cold, northern exposures where Gleysols occur. Cold northern exposures support a forest community (North slope Picea- Abies) in which the same tree species are dominant but productivity is lower and the canopy cover is more open. The Salix-Betula shrub layer is more dense, and a thick mat of hydrophilic mosses and lichens covers the forest floor (Fig. 11). The Picea-Abies and north slope Picea-Abies communities were not always separated on the cover map. Together they occupied about 1,400 acres (567 ha). (b) The Populus Community This community is a long-term sub-climax which occupied 220 acres (89 ha) on steep southern exposures. Black and Dark Gray soils typically supported a mixed woody and herbaceous plant cover. Two sites, with slopes of 60 and 80 percent had an average density of 5,225 aspen (Populus tremuloides) and 4,887 balsam poplar (P. balsamifera) trees per acre. The trees, averaging 27.4 years old at a four inch stump height, averaged only 13.1 feet (4 m) in height and 1.9 inches (4.8 cm) in diameter at breast height. A productive ground cover of grasses and forbs was dominated by lyme grass (Elymus 46 irmovatus). Cryptogams were a minor component and the ground surface cover averaged thirty-two percent living vascular plants and sixty-three percent litter. (c) The Pinus-Salix community This is a sere developing after fires which occurred extensively within the Picea-Abies forest about fifty years ago. There is considerable variability depending mainly on slope, aspect and canopy. The cover tends to be open and, except under a dense tree canopy .consisting mainly of lodge- pole pine (Pinus contorta subsp. latifolia), the understory is well represented, with the shrubs Betula glandulosa, Salix spp. and lingonberry (Vaccinium vitis-idaea) occurring commonly (Table 9). This community, which occupied more than 2,700 acres (1093 ha), was supported by Brunisols with Podsols and Gleysols occurring on cool sites. (d) The Betula-Pinus and Betula-Abies communities These conmunities are open forest associations near treeline. Both have a well-developed shrub layer of Betula and Salix under an open or scattered tree cover. The Betula-Pinus community occurs on the steep south-facing slopes of draws and represents a serai stage following the extensive fires which occurred about fifty years ago. It occupies a total of 168 acres (68 ha) and is characterized by scattered or open stands of Pinus contorta which have replaced the Abies and Picea of the mature forest (Table 9). The Betula-Abies community occupies 40 acres (16 ha) on the north- facing slopes of draws and on protected benches. The vegetation on these cooler exposures is rarely subject to fire and the cover consists mainly of mature Abies lasiocarpa (Table 9). A well developed shrub layer consisting mainly of Betula glandulosa and Salix glauca is characteristic and where burns 47 have occurred, these species form a dense cover which slows forest succession and persists unchanged for long periods.. (e) The Betula-Salix community This plant community is widespread, but it has a discontinuous distribution in close association with other communities so that in most cases it was not delimited on the cover map and its extent was not determined. It occurs on a variety of sites with abundant soil moisture and good drainage, mostly on seepage sites near treeline and in protected places in the alpine meadows. Betula glandulosa and Salix glauca are the dominant species which alone, or in association, form a dense cover about a meter high. Common associates include Elymus innovatus, bluegrasses (Poa spp.), common fireweed (Epilobium angustifolium), tall mertensia (Mertensia paniculata), alpine and heart-leaf arnica (Arnica alpina and A. cordifolia), groundsel (Senecio lugens) and Indian paintbrush (Castilleja niiniata). (f) The Salix-Betula and Salix-Epilobium communities These plant communities which occupy a total of 220 acres (89 ha) have developed on better-drained alluvial terraces and recent stream deposits respectively. The Salix-Betula community is characterized by a more dense cover of shrubs and a reduced cover of grasses and forbs but otherwise the communities are floristically similar and they are described collectively below. Both communities are dominated by shrubs including silvery-green willow (Salix subcoerula) (2)", glaucous willow (S. glauca) (2), Scoulers willow (S. scouleriana) (1) and Betula glandulosa (2). Common forbs include large flowered fireweed (Epilobium latifolium) (3), common horsetail (Equisitunr: arvense) (2), Mertensia paniculata (1), Tilesii sage (Artemesia TilesiiHl) and numerous minor species. Grasses having a combined abundance rating of * Bracketed numbers indicate relative abundance rating in classes 1 to 5 48 3, included rough fescue (Festuca scabrella), bluegrasses (Poa arctioa), P. nevadensis and P. fendleriana), tufted hairgrass (Deschampsia caespitosa), polar grass (Arctagrostis latifolia), spike trisetum (Trisetum spicatum) and Elymus innovatus. (g) Valley meadow plant community Meadows have developed on oold, fine textured Regosols of poorly drained terraces in the valley bottoms. Small meadows, less than 25 acres (10 ha) in extent and totalling only 64 acres (24 ha) in the study area are interspersed with the Salix-Betula community which appears to be gradually invading them. Grasses, forbs and sedges are the major plant species in the meadows, including: Festuca scabrella (4), reed-bent grass (Calamagrostis lapponica) (2), sedges (Carex spp.) (2), meadow rue (Thalictrum occidentale) (2), monkshood (Aconitum delphinifolium (1), Poa spp. (1), northern bedstraw (Galium boreale) (1), Trisetum spicatum (1), Mertensia paniculata (1), Epilobium angustifolium (1) and many minor species. 5.2.2. Alpine Plant Communities Approximately 1300 acres (526 ha) of the study area occurred above treeline, of which fifty percent was comprised of rock, scree or lichen communities. Shrub and alpine meadows made up another 25 percent each of the alpine area. Nine alpine communities; viz. two shrub communities; six grass-forb communities and one cryptogam-forb community are listed in Table 10 and described below. (a) The Betula-Vaccinium uliginosum and Betula-Vaccinium vitris-idaea communities These are relatively stable shrub associations which have a fire history. They occupy a combined total of 232 acres (94 ha) on the lower western and eastern alpine slopes respectively. Each community was sampled Figure 11. The north slope Picea community. Note the abundance of shrubs and the thick mat of mosses and lichens on the forest floor. Figure. 12. The. Betula vaccinium vitis-idaea community on the east slope of Nevis'Mountain. In the background Nevis Creek cuts deeply into the Buckinghorse shales 50 with three paired transects (Tables 11a and lib). Both communities were characterized by an abundance of Betula glandulosa and a sparse cover of grasses and forbs (see Fig. 12), but had significant floristic difference in other respects. Alpine blueberry (Vaccinium uliginosum) was next in importance to Betula glandulosa in the west slope community while this position was occupied by lingonberry (Vaccinium vitis-idaea) in the east slope community. Rough fescue (Festuca scabrella) and sheep fescue (Festuca ovina) were the two major grass species in the community on the west slope. Forbs were more abundant in this community, including species such as spotted saxifrage (Saxifraga tricuspidata), bellflower (Campanula lasiocarpa), Epilobium angustifolium, alpine bistort (Polygonum viviparium) and lupine (Lupinus arcticus) which were not recorded in the east slope community. Soil moisture is more abundant and grasses are more prevalent in the community on the cooler east slope. The two major grasses were holy grass (Hierochloe alpina) and Calamagrostis lapponica, but Festuca scabrella was most abundant in seepage sites. Soils were shallow and stony and cryptogams averaged 57 percent of the ground surface components. Shrub densities and crown diameters were not measured in either of these communities because the shrubs tended to reproduce vegetatively and form inseparable mats. (b) The Elymus-Agropyron community This plant community occurs in small, discontinuous or fragmented units which were not delimited on the cover map, but are symbolized in complex with the closely associated Elymus-Festuca community. It is confined to Chernozem-like soils developed in calcareous parent materials on steep south-facing slopes below 5,500 feet (1676 m) elevation. The soils support a productive cover of grasses, predominantly Elymus innovatus and Table 10. Alpine plant communities at Nevis Creek; their extent with topography and soil characteristics Plant ccmmunity Site No. Elevation Slope Aspect Soil Geologic Parent Area feet (meters) % Great Group Material acres (hectares'. Shrub: Betula-Vaccinium uliginosum : 13A 5350(1630) 46 W *(Eutric Brunisol)Acidic-neutral sand- 136.4(55.2) (S1W) 13B 5400(1645) 50 w stone and shales Betula-Vaccinium 6A 5680(1730) 34 E.NE (Dystric Brunisol Acidic sandstones 142(57.5) vitis-idaea 6B 5575(1698) 38 and Regosol) and shales (S1E) 6C 5700(17397) 32 NE Alpine grass and herbs Elymus-Agropyron 10A 5120(1561) 59 S Eutric Brunisol Calcareous colluvium 15 (6.1) (GIB) 10B 5000(1524) 52 S Calcareous sandstone 10C 5150(1559) 59 S Calcareous colluvium Elymus-Festuca (GI) 1A 5450(1662) 43 S Eutric Brunisol Calcareous sedimentary 60(24.3) IB 5325(1622) 53 SW Eutric Brunisol rock 1C 5500(1676) 40 SE Dystric Brunisol Acidic sandstone ID 5500(1676) 48 SE Eutric Brunisol Neutral sandstone and colluvium Dryas-Festuca (G2) 2A 5700(1737) 26 SW Eutric Brunisol Neutral weathered 42 (17) 2B 5775(1759) 26 SW Eutric Brunisol sandstone 2C 5650(1722) 26 SW Eutric Brunisol n Calamagrostis- 5A 6000(1829) 24 ESE Dystric Brunisol Acidic marine siltstone 190(76.9) Hierochloe (G4) 5B 6300(1919) 18 E Dystric Brunisol Acidic marine siltstone 5C 6200(1890) 24 E Dystric Brunisol Acidic marine siltstone 5D 6250(1905) 35 E Regosol Acidic marine siltstone Cn H Table 10. (Cont'd) Plant Community Site No. Elevation Slope Aspect Soil Geologic Parent' Area feet(meters)" % Great Group Material acres(hectares) Festuca-Dryas (G5) 3A 6100(1859) 56 SW Humisol Calcareous colluvium 19(7.7) 3B 5810(1771) 68 SW Regosol (Marine sandstone and siltstone) Silene-Calamagrostis 4A 6350(1935) undulating - Dystric Brunisol Acidic sandstone 3(1.2) TG3l 4B 6420(1957) undulating - Dystric Brunisol Acidic sandstone Cryptogam - Salix (N) 18 5300(1615) 35 N Humisol Colluvium 20(8.1) it Bracketed figures are tentative cn 53 Table 11a. Major plant species coverage and frequency (C/F) for two sites in the Betula-Vaccinium uliginosum community Species Study Site 13A 13B A. Grasses: C/F C/F Festuca scabrella tr/5 8/35 Festuca ovina 2/55 2/55 Poa arctica tr/10 2/55 B. Sedges: Kobresia myosuroides 2/40 2/40 Carex atrata tr/5 1/10 C Forbs: Saxifraga tricuspidata 5/60 5/75 Campanula lasiocarpa 1/40 3/55 Epilobium angustifolium 1/45 1/35 Polygonum viviparum 1/30 1/45 Lupinus arcticus tr/5 2/15 Luzula spicata tr/20 1/35 Art ernesia norvegica tr/25 tr/10 Stellaria longipes 0/5 1/45 D. Shrubs: Betula glandulosa 20/70 39/70 Vaccinium uliginosum 19/55 10/40 Vaccinium vitis-idaea 9/25 . 10/25 Arctostaphylos uva-ursi 2/5 tr/5 Rhododendron lapponicum tr/5 1/10 Tr = Trace or less than 0.5% 54 Table lib. Shrub measurements and ground surface components for two sites in the Betula-Vaccinium uliginosum community Species and Study site Components 13A 13B A. Shrubs Ix(%) Av.Ht.(ins) I(%) Av.Ht.(ins) Betula glandulosa 28 7.4 2.3 6 Vaccinium uliginosum 14 2.5 6 2.1 Vaccinium vitis-idaea 4 0.5 4 0.5 Rhododendron lapponicum 0 2 2 B. Ground surface components (%) Living vascular plants 20 20 Litter 20 15 Rock 38 25 Bare soil 0 0 Cryptogams 23 40 = Foliage intercept in percent along 15 meter transect 55 Table 12a. Major plant species C/F, for three sites in the Betula-Vaccinium vitis-idaea community Species Study Site 6A 6B 6C C/F C/F C/F A. Grasses: Hierochloe alpina 10/80 8/60 14/90 Calamagrostis lapponica 11/70 6/30 11/80 Festuca ovina 1/45 3/35 2/75 Festuca scabrella 5/40 0/0 3/30 Pea leptoccma 3/60 1/15 tr/20 B. Forbs: Luzula spicata 1/35 tr/5 2/30 Stellaria longjpes 1/50 tr/20 1/65 Artemesia norvegica 1/5 0/0 0/0p C. Shrubs: Betula glandulosa 61/100 59/95 68/100 Vaccinium vitis-idaea 2/10 12/35 16/50 Vaccinium uliginosum 4/15 4/10 5/15 Ledum groenlandicum 0/0 5/35 0/0 Tr = trace or less than 0.5% 56 Table 12b. Shrub measurements and ground surface components for three sites in the Betula-Vaccinium vitis-idaea community Species and Study Site Components 6A 6B 6C A. Shrubs: I(%) Av.Ht.(Ins) I(%) Av.Ht.(Ins) I(%) Av.Ht. Ins Betula glandulosa 40 4.7 37 4.8 38 5.5 Vaccinium vitis-idaea 1 0.5 7 0.5 2 2.0 Vaccinium uliginosum 2 4 2 7 2.0 Ledum groenlandicum 0 1 2 0 B. Ground surface components (%) Living vascular plants 22.5 21 29 Litter 22.5 16 31 Rock 10 18 9 Bare soil 5 1 0 Cryptogams 40 44 24 57 bearded wheatgrass (Agropyron subsecundum) (Fig. 13). The community, which was sampled at three sites using paired 15 meter transects (Table 13 a 8 b) is characterized by having the most favourable microclimate and soils for forage growth and was the most productive and heavily grazed of the alpine communities studied. The annual growth is almost completely removed by grazing sheep each winter, and the vegetation in this community, both in terms of floristics and productivity, must be considered a product, in part, of heavy grazing, trampling and fertilization with fecal matter, (c) The Elymus-Festuca community This community, supported by Eutric Brunisols, dominates alpine slopes with a southern exposure (Fig. 14). Broken by unvegetated scree and rock, and by components of the Betula-Salix and Elymus-Agropyron communities, it occupies a little more than half of the south-facing slopes of Nevis Mountain or about 60 acres (24 ha). It is described at four sites with slopes ranging from forty to fifty-three percent and aspects from southwest to southeast (Table 14). The vegetation, which is dominated by Elymus innovatus and Festuca scabrella, reflects the variability of slope, aspect and soils. Festuca scabrella has a wide tolerance range and is one of the most widespread and abundant grass species in the study area as a whole. It favours areas where snow covers the slopes in winter and where there is an abundant supply of soil moisture, and, in the Elymus-Festuca community, Festuca scabrella is relatively more abundant than sedges (Kobresia myosuroides) on cool, wet sites and more acidic soils. Elymus innovatus favours warmer slopes and less acidic soils while wheatgrass (Agropyron subsecundum and A. violaceum) are restricted to warm slopes with neutral to alkaline soils. There is an abundance and variety of forbs, but white dryas (Dryas integrifolia) dominates the forb canopy cover, especially on dry sites where 58 Figure 13. The Elymus-Agropyron community. Note the dense cover of grasses and the lack of weathered forage. Figure 14. The Elymus-Festuca community. Note the' moderately dense cover cr grasses and forbs including weathered forage of previous seasons growth. 59 soils are not too acidic. Shrubby cinquefoil (Potentilla fruticosa), Salix glauca and Betula glandulosa are common shrubs throughout the community while bearberry (Arctostaphylos uva-ursi) commonly forms spreading mats on steep slopes and unstable soils. An abundance of weathered forage from previous years growth reflects the slow recycling of organic matter in this alpine environment and only moderate utilization of the forage by sheep. (d) The Dryas-Festuca community The Dryas-Festuca community is supported by Eutric Brunisols on exposed ridges or hogsbacks on the western slope of the mountain. It occupies a total of 42 acres (17 ha) and is characterized by a relative abundance of forbs and sparse cover of grasses (Fig. 15). This community is described at three sites with elevations from 5,650 to 5,775 feet (1722 to 1759 m), an average slope of 26 percent and a southwestern aspect (Table 15). Festuca scabrella dominates with low-growing perennial forbs including Dryas integrifolia, Polygonum viviparum, prickly saxifrage (Saxifraga tricuspidata) and moss campion (Silene acaulis) on this cool, windy site. Elymus innovatus and Agropyron spp., common in adjacent communities are absent here, favouring warmer sites and more calcareous soils. (e) The Calamagrostis-Hierochloe community The Calamagrostis-Hierochloe community lies above the Betula- Vaccinium shrub association on the eastern alpine slope (Fig. 16). Snow cover is more continuous and longer lasting than on southern and western exposures and Dystric Brunisols and Regosols have developed on acidic parent materials. The plant community on this cool exposure with acidic soils (pH 3.5) has been described at four sites with slopes ranging from eighteen to twenty-eight percent and aspects ranging from southeast to north- 60 Table 13a. Major plant species C/F, for three sites in the Elymus-Agropyron community Species Study Sites 10A 10B 10C Grasses: C/F C/F C/F Hordeae* 80/100 74/100 67/100 Poa sp.1 1/55 2/30 23/95 Poa rupicola 1/30 2/40 3/80 Poa arctica tr/5 - ' 2/40 B. Forbs: Oxytropis spp. 10/50 6/25 10/95 Hedysarum alpinum 6/30 13/65 7/45 Achillea millefolium 14/80 4/55 8/75 Epilobium angustifolium 6/35 16/95 3/50 Myosotis alpestris 2/30 7/100 10/95 Galium boreale 8/75 7/90 3/65 Sile'ne repens 11/100 1/30 5/90 C Shrubs: Rosa acicularis 3/30 0/0 3/30 Potentilla fruticosa 0/0 0/0 0/0 " By ocular estimate Elymus innovatus 30% 95% 60% Agropyron subsecundum 70% 5% 40% "tentatively P. glauca Table 13b. Shrub measurements and ground surface components for three sites in the Elymus-Agropyron community Species and Study Site Components A. Shrubs: Density1 Av.Ht. Av.Crown I(%) Density Av.Ht. Av.Crown I(%) Density Av.Ht. Av. (ins) diam(ihs) (ins) diam(ins) (ins) Crown Diam. (ins) Rosa acicularis 70 2.2 6 3.7 0 0 100 4.5 6.5 3.9 Potentilla fruticosa 0 0 40 2.2 15.3 15.4 20 0.06 13 9.5 B. Ground surface components (%) Living vascular plants 28 16 24 Litter 5 63 28 Rock 10 1 9 Bare soil 58 20 40 Crypogams 0 0 0 1Density = No. of plants per square meter CD M Table 14a. Major plant species C/F for four sites in the Elymus 'Festuca community Species Study sites 1B 1C ' ID A. Grasses: C/F •C/F C/F C/F Elymus innovatus "32/100 27/93 19/98 * 33/100 Festuca scabrella 10/55 13/58 10/88 46/100 Poa arctica 4/60 1/30 3/63 2/145 Festuca ovina 2/40 tr/10 0/0 6/80 Poa rupicola tr/3 0/8 1/15 3/30 Tnsetum spicatum 2/43 tr/18 1/28 1/45 B. Sedges: Kobresia myosuroides tr/15 0/0 14/73 0/0 C. Forbs: Dryas integrifolia 15/45 13/33 0/0 17/80 Lupinus arcticus" 13/55 7/60 8/55 6/70 Polygonum viviparum 11/90 3/63 1/20 15/100 Mertensia paniculata 12/40 3/15 4/43 1/30 Saxifraga tricuspidata 3/33 6/65 7/38 3/40 Aeoniturn delphinifolium 7/83 1/35 4/58 2/90 Cerastium spp. 3/88 1/45 1/28 2/30 Pedicularis spp. tr/10 1/10 0/0 4/65 Galium boreale 2/20 1/28 3/75 0/0 Zygadenus elegans 2/38 0/0 1/28 3.30 Myosoti~alpestris 2/53 1/25 1/20 1/60 Gentiana spp. 1/48 2/50 2/25 0/0 Rumex acetosa 2/40 0/0 1/25 1/30 CO Polemonium acutiflorum 0/0 1/25 0/0 2/40 ro Potentilla spp. 2/23 0/0 1/35 0/0 " Includes 10-20 percent Agropyron subsecundum Table 15a. Major plant species C/F for three sites in -the Dryas-Festuca community Species Study site and Components 2A 2B" 2C ~C7F C/F ~C7F A. Grasses: Festuca scabrella 10/53 10/80 8/75 Festuca ovina 4/10 1/78 5/98 Poa arctica 2/48 2/55 1/45 Trisetum spicatum 2/85 1/38 1/73 Poa rupTcola 1/15 1/15 B. Sedges: Kobresia myosuroides 1/5 1/38 3/30 C. Forbs: Dryas integrifolia 19/100 15/95 15/93 Lupinus arcticus 5/88 7/98 6/93 Polygonum viviparum 6/100 5/100 5/9 8 Silene acaulis 3/60 2/10 6/33 Saxifraga tricuspidata 4/63 3/53 3/53 Cerastium spp. 1/23 1/20 5/13 Oxytropis" spp. 2/33 1/23 3/43 Aconitum~delphinifolium 2/73 1/40 2/33 Polemonlum acutiflorum 2/58 1/28 2/43 Saxifraga nivalis 1/13 1/18 3/18 SenecicTTugens i 1/68 2/40 1/63 Pedicular is si 1/55 1/70 2/58 Myosotis alpestris 1/18 1/25 1/20 Luzula spicata 1/40 1/15 1/30 Gentiana propinqua 1/63 1/58 1/43 CO CO Table 15a. (continued) Species Study Site and Components 2A 2B" 2C C/F C/F C/F Campanula uniflora 1/38 1/25 1/33 Rumex acetosa 1/20 0/0 1/15 Potentilla spp. 1/15 1/43 tr/28 D. Shrubs: Potentilla fruticosa 2/3 6/18 1/9 Salix glauca 5/5 0/0 1/9 Table 15b. Shrub measurement and Ground Surface Components for three sites in the Dryas-Festuca community Species Study site 2C 2A 2E 2 2 2 F Density Av. Average F Density Av. Average F Density Av. Average (%) (No/M2) Ht. crown dia. (%) (No/M ) Ht. crown dia. (%) (No/M2) Ht. crown dia. In. (In) (In.) (In) In. (In) A. Shrubs: Potentilla fruticosa 10 tr 8 2.5 70 0.6 5.1 7.1 30 0.2 6 6 Salix glauca 10 tr 4 6 35 0.2 5 9 B. Ground surface components (%) Living vascular plant 49 41 37 Litter 26 • 35 29 Rock .9 4 12 Bare soil 0 7 0 Cryptogams 16 13 22 CT) Cn Figure 15. The Dryas-Festuca ccmmunitv on exposed ridge. Note the abundance of lew-growing Dryas-integrifolia and the sparse cover of grasses. Figure 16. The CalaTasrostis-Hierochloe cennunitv. Note the absence of fcrbs and the prevalence of cryptogams on rock and ground surfaces. 67 Table 16a. Major plant species c/f and ground surface conditions for four sites in the Calamagrostis-Hierochloe community Species and Study sites Components 5A 5B 5C 5D C/F C/F C/F C/F A. Grasses: Hierochloe alpina 5/23 2/75 20/95 25/100 Calamagrostis lapponioa 8/77 2/55 20/95 24/100 Festuca scabrella 13/67 6/85 23/80 0/0 Poa spp. 4/45 1/75 4/85 3/35 B. Sedges: Carex spp. 2/33 1/40 2/5 2/5 C. Forbs: Luzula spicata 3/55 1/80 15/90 24/95 Artemisia norvegica 3/58 tr/15 6/73 0/0 Campanula lasiocarpa 0/0 1/60 6/40 tr/5 Silene acaulis 4/13 3/35 2/23 1/10 Aconitum delphinifolium 2/55 tr/80 tr/30 tr/20 Potentilla hyparctica 1/28 1/70 tr/3 tr/5 Polygonum viviparum 1/38 1/70 tr/3 tr/5 Polemoraum acutiflorum 1/13 1/40 tr/10 tr/25 Stellaria longipes 1/70 tr/60 tr/43 . 0/0 D. Shrubs: Vaccinium vitis-idaea 9/48 9/40 0/0 13/10( Vaccinium leguminosae 8/20 0/0 0/0 0/0 Salix polaris 3/50 3/80 0/0 0/0 2 F(%) = percent frequency by occurence in 1/10M plots T = trace or less than 0.5% 68 Table 16b. Ground surface components (%) for four sites in the 5A 5B y ^U"5C 5D Living vascular plant 25 35 29 29 Litter 29 12 29 35 Rock 4 1 9 5 Bare ground 3 6 0 0 Cryptogams 39 46 33 31 69 Table 17a. Major plant species C/F for two sites in the Festuca-Dryas ccmmunity and one site in the Silene-Calamagrostis community Species 3A 3B 4A Study site C/F C/F C/F Grasses: Festuca scabrella 43/88 63/95 1/35 Festuca ovina 2/40 6/45 1/35 Poa spp. 1/15 5/30 Trisetum spicatum tr/8 1/20 1/10 Calamagrostis lapponica 0/0 0/0 2/80 Hierochloe alpina 0/0 0/0 1/50 Poa arctica 0/0 0/0 1/30 Sedges: Kobresia myosuroides 1/8 8/40 tr/5 Forbs: Dryas integrifolia 35/82 5/30 0/0 Lupinus arcticus 12/63 13/70 0/0 Aconitum delphinif olium 4/47 20/100 1/55 Senecio lugens 13/44 8/75 0/0 Polemonium acutiflorum 3/47 13/95 2/5 Gentiania propinqua 1/30 7/85 0/0 Silene acaulis 1/10 2/10 5/45 Luzula spicata" 0/0 0/0 2/100 Mertensia paniculata 3/40 8/65 0/0 Myosotis alpestris 5/10 tr/50 0/0 Polygonum viviparum 2/47 1/25 0/0 Pedicularis spp. 1/38 1/25 0/0 Solidago multriadiata 2/24 0/0 0/0 Campanula spp. 0/0 0/0 1/35 Potentilla spp. tr/3 1/15 1/45 Cerastium spp. tr/12 1/30 tr/15 Shrubs: Potentilla fruticosa 7/35 0/0 0/0 70 Table 17b. Shrub measurements and ground surface components for two sites in the Festuca-Dryas community and one site in the Silene-Calamagrostis community Species and Study Site Components 3A 3B ^ A. Shrubs: I(%) D Av. Av.Crown I(%) D I(%) D Ht.(ins) Dia.(ins) Potentilla 80 1 9.4 12.4 0 0 0 0 . fruticosa B. Ground surface components (%) Living vascular plant 40 65 • 10 Litter 35 33 25 Bare soil 2 0 3 Rock 14 2 1 Cryptogams 9 1 61 71 Figure 17. The cryptogam-Salix community. Note the moss-lichen patches. The tall shrubs in the immediate background are about 1 meter high. 72 Table 18. Relative use of alpine plant communities at Nevis Creek as indicated by pellet group counts and the season of their main use as determined from observations. Plant Extent No.per 2 No. sample2 Main Season Community Acres (hectares) sq.yd.(per M ) plots (3M ) of Use Elymus-Agropyron 15 (6.1) 3.790 (4.533) 30 Winter and spring Festuca-Dryas 19 (7.7) 0.911 (1.090) 20 Summer Elymus-Festuca 60 (24.3) 0.591 (0.707) 80 Winter and spring Dryas-Festuca 42 (17.0) 0.504 (0.603) 60 Winter Calamagrostis- 190 (76.9) 0.278 (0.332) 60 Summer Hierochloe Silene-Calamagrostis 3 (1.2) 0.276 (0.330) 10 Summer Betula-Vaccinium 142 (57.5) 0.254 (0.310) 30 Summer vitis-idaea Betula-Vaccinium 90 (36.4) 0.192 (0.230) 20 Summer uliginosum Table 19. Net productivity and combined protein levels of oven-dried forage from the three most important plant communities for wintering sheep Forage Weight Altitude 2 Crude otein Slope Cg/m i S.E.) CLbs/acre) ^ % lbs/acre Plant Community Site Exposure 1969 1970 1969 1970 Fall/70 Sp/70 Diff Fall 1970 2. Elymus-Agropyron 10A 5120-5150 239.2T7.3 2081.1 9.46 12.09 196.87 10B 52-59% 139.9t8.9 1243.0 9.87 6.83 122.68 IOC S 163.6-7.4 1465.0 10.53 6.89 154.26 Mean Av. 180.9-7.9 1596.0 9.95 8.60 -13.6 157.94 3. Elymus-Festuca 1A 5325-55— 84.9-10.0 953.5 ,753.6 8.85 4.43 66.69 IB 40-53% 152.9T13.4 603.3 1371.2 8.82 4.60 120.94 1C SE-SW 113.9-12.0 759.7 1021.7 10.91 6.23 111.47 ID 141.3-14.9 1033.8 1264.7 8.34 105.48 Mean Av. 94.1^80 123.3-12.6 836.3 1102.8 9.23 5.08 -44.9 101.45 4. Dryas-Festuca 2A 5650-5775 36.9-1.9 384.6 328.4 7.79 7.04 25.58 2B 26% 36.5r3.4 326.5 324.1 8.56 6.63 27.74 2C SW 53.0-2.8 328.6 471.3 7.51 7.09 35.39 Mean Av. 77.7-7.6 42.1^2.7 346.6 374.6 8.07 6.92 -14.3 29.57 74 east (Table 16). Study site altitudes ranged from 6,000 to 6,300 feet (1829 to 1919 m). This community occupies 190 acres (77 ha) and is dominated by the grasses: Calamagrostis lapponica, alpine holy grass (Hierochloe alpina) and Festuca scabrella, the latter species being relatively more abundant in swales and seepage sites. With the exception of grass-like spike woodrush (Luzula spicata), forbs are poorly represented. Low- growing Vaccinium vitis-idaea and V_. uliginosum are common shrubs on better- drained sites while crowberry (Fjripetrum nigrum), common juniper (Juniperus communis) and heather (Cassiope tetragona) occur on protected sites within the grassland community. Cryptogams are the main ground surface cover component, averaging 37 percent at the four sites studied, (f) The Festuca-Dryas community The Festuca-Dryas community occupies nineteen acres (7.7 ha) on a steep southwestern exposure between 5,750 and 6,400 feet (1753 and 1951 m) altitude. It was studied with paired transects at two sites having slopes of 56 and 48 percent (Table 17). The community is supported mainly by relatively deep, dark coloured organic soils developed on calcareous colluvium and characterized by abundant basic seepage waters. The species composition of this plant community is similar to that of the Dryas-Festuca type immediately below, especially for the major plants; Festuca scabrella, Dryas integrifolia and Lupinus arcticus. However, it is a much more productive community as shown by the percent canopy coverage which averaged 85.5 percent as opposed to 31.6 percent for the three common dominants. It differs in other respects also, in that it includes species such as Mertensia paniculata, large-flowered anemone (Anemone parviflora). Saxifraga tricuspidata, which is well represented on the drier Dryas-Festuca site is lacking in this community. 75 (g) The Silene-Calamagrostis community The Silene-Calamagrostis community occupies only three acres (1.2 ha) on the narrow, undulating ridge of the mountain top which lies between 6,300 and 6,675 feet (1919 and 2034 m) altitude. Climatic conditions are harsh, with early freezing temperatures, strong drying winds and accumulated drift snow which remains on parts of the site well into the month of June. Dystric Brunisolic soils developed on acidic sandstone support an inpoverished community of grasses and low-growing forbs which was studied at one site using paired transects (Table 17). Silene acaulis, Calamagrostis lapponica, Luzula spicata and Jacobs ladder (Polemonium acutiflorum) were the only vascular species having a canopy cover exceeding one percent. Shrubs were lacking and lichens and mosses were the main ground surface components., totalling 60 percent at the site studied. (g) The Gryptogam-Salix community This community, which was studied on the south side of the Nevis valley, occupied 20 acres (8 ha) on alpine slopes with a northern exposure. Because it was not used by sheep, it was investigated only at a reconnaissance level. On the cold, northern alpine slopes, Humic Gleysols containing frozen layers support a hydrophylic plant association of low productivity. The vegetation consisted largely of mosses and lichens including: Sphagnum rubeHum, S. nemoreum, Pholia sphagnicola, Halacomium palustre and Cladonia alpestris. Common vascular associates included: retted willow (Salix reticulata), northern dwarf willow (S.polaris), Dryas integrifolia, dwarf horsetail (Equisetum scirpoides), Festuca scabrella and Lupinus arcticus. Thickets of Betula glandulosa, Salix glauca, and hairy willow (S. lanata) occur on better-drained sites within this community, (Fig. 17). This community, which has cognates in the tundra of higher latitudes, appears to be spreading into communities where grasses, sedges 76 and shrubs are more common (V.C. Brink, pers. comm.). 5.2.3. Importance of plant communities to sheep Observations indicate that stone sheep in the northern foothills depend almost exclusively on alpine vegetation, for their forage requirements. Low elevation grasslands are limited to fine textured alluvial soils in the valley bottoms or/serai grasslands which tend to be rapidly invaded by shrubs. x In summer, the sheep have a wide choice of feeding areas and they grazed most of the alpine plant communities distributed over about 560 acres (2.27 ha) at one time or another during this season. Feeding sheep were observed most frequently in the Calamagrostis-Hierochloe and Betula-Vaccinium vitis-idaea communities on the east slope and in the Festuca-Dryas community, high on the west slope of Nevis Mountain during the summer. Use of these areas was severely limited in winter by snow cover. The results of pellet group counts, presented in Table 18 provides a measure of the relative use of the alpine plant communities. The Calamagrostis-Hierochloe and Betula- Vaccinium vitis-idaea communities are extensive, and though pellet groups counts indicate they• ranked only sixth and seventh respectively in terms of use per unit area, they ranked second and third in terms of use by total area. The Festuca-Dryas-community, only 19 acres (7.7 ha) in extent, ranked only sixth in terms of use by total area, but it ranked second in terms of area use per unit /indicating that it was highly favoured by sheep during the summer months. In winter, sheep are restricted to exposed places where snow cover is reduced by exposure to sun and wind. At Nevis Creek the sheep mainly used the Elymus-Agropyron and Elymus Festuca communities on slopes with a southern aspect and the Dryas-Festuca community on windswept ridges with a western 77 aspect in winter. Altogether these communities occupied about 117 acres (47 ha) on Nevis Mountain. The results of pellet group counts (Table 18) indicate that the Elymus Agropyron community received the heaviest use per unit area and, in spite of its limited extent, was used more by sheep than any other alpine plant community. This community was also used heavily in the spring since the first new growth of spring occurs here but it was rarely used during the summer months. The Elymus-Festuca and Dryas-Festuca communities respectively ranked third and fourth in use per unit area and fourth and fifth in terms of use per total area. These communities were used mainly in the winter, but to a lesser extent, in spring, summer and fall as well. Food habits of the sheep are discussed more specifically in section 6.2.2. 5.2.4. Forage production and quality on the winter range Productivity and percent crude protein results from the three main plant communities used by wintering sheep are shown in Table 19. (a) Productivity The ElyiiMs-Agropyron community was the most productive on the winter range, yielding an average of 1,596 pounds of oven -dried forage per acre (1,789 Kg per ha) in 1970. Grasses made up more than 80 percent of this amount by weight. The Elymus-Festuca community yielded 1,103 pounds per acre (1,236 Kg per ha) or about 70 percent of the amount yielded by the latter community while the Dryas-Festuca community yielded only 375 pounds per acre (420 Kg per ha) or less than a quarter of that yielded by the Elymus-Agropyron community. Grasses made up 70 percent and forbs 30 percent by weight in the Elymus-Festuca community. These class proportions were reversed in the Dryas-Festuca community where Lupinus arcticus contributed the most for forbs. 78 Although the Elymus-Agropyron community produced the most, and the Dryas-Festuca community the least forage on a unit area basis, the Elymus- Festuca community produced about 63 percent of the total forage produced by these three principal winter range communities. The Elymus-Agropyron community produced about 23 percent and the Dryas-Festuca community about 15% of this amount. (b) Forage quality As shown by the results in Table 19, percent crude protein was highest for the fall yield samples from the Elymus-Agropyron community which averaged 9.95 percent as compared to 9.23 percent for the Elymus- Festuca community and 8.07 percent for the Dryas-Festuca community. On a total area basis, these respective communities produced fall yields of about 2370 pounds (2,656 kilograms), 6087 pounds (6,823 Kg) and 561.8 pounds (628.8 Kg) of crude protein. The decline in crude protein content from fall yield samples to spring samples of weathered vegetation was 13.6 percent for the Elymus-Agropyron community, 14.3 percent for the Dryas-Festuca community and 44.9 percent for the Elymus-Festuca community. The 13.6 percent decline in crude protein indicated for the Elymus-Agropyron community is a low estimate because plots at site 10A were clipped late, after spring growth had begun. The actual decline in crude protein for this community was probably about 30 percent. 5.2.5. Forage utilization and wastage on the winter range The removal of forage by grazing sheep and wastage due to weathering in the three principal plant communities on the winter range during the winter of 1969/70 is shown in Table 20. The forage removed by grazing sheep includes that unknown portion lost through breakage due to trampling or pawing to remove snow. 79 Table 20. Forage removed by wintering sheep and weathering in the principal winter range communities during the winter of 1969/70 Plant Net Forage removed by Forage removed Total forage Community Productivity weathering by sheep removed lbs/acre % forage lbs/acre % lbs/acre \ produced Elymus-Agropyron 1596 - - 1433 90 Elymus-Festuca 987 128 13 188 19 316 32 Dryas-Festuca 482 222 46 46 9.5 268 55.5 The results in Table 20 show that 90 percent by dry weight of the forage produced by the Elymus-Agropyron community was removed over the winter period (Figs. 18 and 19). Although the proportion lost due to weathering was not measured, it is not expected to have exceeded the amount (13 percent) removed by this means in the adjacent Elymus-Festuca community. Thus, about 80 percent of the forage produced by the Elymus-Agropyron community and only 19 percent of that produced by the Elymus-Festuca community was removed through grazing. Although 55 percent of the forage produced by the Dryas-Festuca community was removed over the winter period, only 9.5 percent was removed by grazing sheep, the other 46 percent being removed by weathering on this windswept site. On the basis of forage removed per unit area, the Elymus-Agropyron community provided about 57 percent, the Elymus-Festuca community 38.5 percent and the Dryas-Festuca community 4.5 percent by dry weight of the total forage removed by wintering sheep from these three plant communities. 80 5.2.6. Discussion While the description of plant communities below treeline is superficial, it was meant to be a simple, rather than a detailed account of that portion of the study area which, like the alpine habitat, is poorly documented in the literature. Much of the climax vegetation below treeline has been replaced with seres dominated by willow, glandular birch and lodgepole pine. Succession proceeds slowly at this latitude even in the fire produced seres below treeline. However, while some serai communities persist with little change for long periods of time, others are characterized by a rapid transition. For example, most serai grasslands are rapidly invaded by shrubs which re-established quickly and soon reach or exceed their former abundance because of their ability to reproduce vegetatively from undamaged root stocks. Alpine plant communities have been influenced little by fire except near treeline. Coniferous trees were slowly invading lower limits of the Betula-Vaccinium shrub associations on east and west-facing slopes and the Populus community was invading the lower Elymus-Agropyron and Elymus-Festuca communities on the south-facing slope of Nevis Mountain. At higher elevations, alpine plant communities are essentially in climax or sub-climax condition. Even the Elymus-Agropyron community can be considered a stable sub-climax which has developed through centuries of heavy seasonal grooming by the native sheep. Even in essentially stable plant communities uninfluenced by fire, however, there are visible trends indicating long-term vegetation change. The persistent spread of mosses and lichens on to grassland and shrub communities of cool exposures, and of shrubs on to grasslands of warm slopes and valley terraces are examples of such trends. In the alpine, 81 trees and shrubs are eliminated from unprotected places but stunted alpine fir and low shrubs such as willows, glandular birch, blueberries and crowberry occur on sites protected from severe frost by a blanket of snow. As trees and shrubs cause drifting snow to accumulate, they create a microclimate favourable to their further spread. The slow cumulative drift of shrubs is particularly apparent as spreading patches of white willow and glandular birch on warm alpine slopes and valley grasslands. Although alpine plant communities were investigated in much greater depth than those below treeline, the vegetation showed a high degree of complexity and time limited the intensity and therefore the adequacy of sampling in this study. The results of floristic studies are comparable for all plant communities studied in detail even though the adequacy of sampling varies. Also, the restricted random design of the macroplot method allows for the testing of between as well as within plot variability. Sampling adequacy was tested during the study by plotting coverage and frequency percentage of major and minor taxa against the number of plots studied in a given stand (Daubenmire, 1959). From this, it was apparent that the level of sampling which time permitted was adequate for major but not for minor taxa in any given community. Thus, the results are less than descriptive for plant communities with a large number of minor species than for communities which contained relatively fewer minor species. All of the alpine plant communities on Nevis Mountain were used by sheep although use varied seasonally and in intensity. Pellet group counts and observations indicated that although sheep used the Calamagrostis- Hierochloe and Betula-Vaccinium vitis-idaea communities extensively during the summer, they favoured the Festuca-Dryas community which received the 82 heaviest use per unit during this period. Three plant communities limited to 117 acres (45 ha) on warm southern and western exposures provided critical winter range for the sheep and were investigated in greater depth. Productivity estimates for these communities were based on a limited sample of fall forage yields. The yields actually provide a low estimate of net productivity since only the aerial portion of plants more than one half-inch above ground level was included and because the forage was clipped at late maturity when some grasses had reached the seed dissemination stage and loss by shattering had occurred. However, the results provide a reasonable estimate of net primary productivity and of forage available for the sheep at the onset of winter. The results are comparable with estimates from alpine environments in other parts of the world including those of the more southern latitudes of British Columbia (Brink, V.C., A. Luckhurst and D. Morrison, 1972). The variation in yields from different slopes and aspects emphasizes the correlation between soils, climate and vegetative productivity. Crude protein content of forage from the alpine winter range was typically high and its decline over the winter period was low compared with levels in native forage plants from lower elevations and latitudes (Johnson and Bezeau, 1968). The crude protein results indicate that only forage from the Elymus-Agropyron community, which had the highest crude protein levels in the fall, maintained average crude protein levels (8.60 percent) within the minimum range of 7.0 to 9.5 percent recommended by the National Research Council (1957) for growth and gestation in domestic sheep. However, crude protein estimates for weathered forage from this community are known to be high and the highest actual level for weathered forage appears to be the 6.92 percent recorded for the Dryas- Festuca community which had the lowest crude protein content initially. 83 Figure 18. Clipping grazed forage plots at site No. IDA in the Elymus-Agropyron community. Note the sparseness of remaining forage. Photo taken May 16/70. Figure 19. A temporary enclosure at Site 10A. Note the productive growth, mainly grasses. Photo taken July 31/70. 84 Buebenik (cited by Dirchl, 1963) reported that a diet containing about 7 percent crude protein met the minimum winter requirements for mouflons (Ovis musemon). Although crude protein content of weathered forage from the principal (Elymus-Festuca) community on the winter range averaged only 5.08 percent, this is comparable with levels reported for forages from native sheep ranges in more southerly latitudes (Demarchi, D.A. 1970, Demarchi, R.A., 1968, and Johnson and Bezeau, 1968). 85 6. STONE SHEEP 6.1 Methods Seasonal movements, distribution and population characteristics of stone sheep were determined from aerial and ground observations. Sheep were classified on the basis of horn size, body size and sex in eight classes (Geist, 1968). Ewes over 2 years old cannot be separated on the basis of age and were grouped as mature ewes. Rams, however, were separated on the basis of horn size into four age classes which included animals predominantly of the following ages: Class I rams, 2 to 3 years old; Class II rams, 3 to 6 years old; Class III rams, 6 to 8 years old, and Class IV rams, 8 years and older. Productivity estimates were determined from early summer ewe and lamb ratios while changes in sex and age ratios through time provided a relative measure of juvenile and adult mortality. Food habits were determined by rumen sample analysis, by recording grazed and ungrazed plant species in a total of fifty 0.1 square meter sample plots and by observing feeding animals. Five 1-quart (1.136 L) rumen samples were collected from sheep feeding on the winter range. These were washed and screened and a volumetric estimate of the identifiable material was determined by water displacement. Plants were identified by gross vegetative characteristics with the aid of a dissecting scope and a reference plant collection. A 500 ml subsample was analyzed by the point analysis method described by Chamrad and Box (1964). Grasses and sedges, grouped as a single class in the volumetric analysis, were identified, as far as possible, to species in this analysis. Only one of the five rumen samples was analyzed by this method because, although it provided some worthwhile data, it was time consuming and limited 86 by problems in sampling and identification. A soil sample from the mineral lick at Nevis Creek and an unrelated sample from the sheep summer range were analyzed for major elements by the U.S.D.A. soil testing laboratory, Ohio State University, Columbus, and for minor elements by the Geology Department, University of British Columbia, Vancouver. Causes of mortality as inferred from field observations are discussed generally in terms of competition for forage and the incidence of injury, parasites, disease and predation, including hunting. Additional information was obtained from autopsy and examination of animals shot for study purposes or by hunters and from hunter harvest records. 6.2 Results 6.2.1 Seasonal movements and distribution As indicated in Section 5.2.3 stone sheep in the northern Rocky Mountains occur generally above treeline. Typically, they are segregated into ram and ewe:juvenile groups or bands which tend to occupy distinct "home ranges" through most of the year. During the rut, in late fall and early winter, the rams leave their summer range to visit ewe-juvenile ranges where they spend a greater or lesser part of the winter. The sheep range on Nevis Mountain was essentially a ewe-juvenile home range-. It supported few rams older than yearlings and none older than three years except in late fall and winter when rams came to breed and to graze on the exposed slopes where snow depths were reduced. Winter snow cover had a major influence on the distribution of sheep. With the first snows of autumn, the sheep moved down from the high summer range to feed on lower alpine slopes with a southern or western exposure. As winds swept the higher slopes and ridges free of snow, the sheep tended to move up and 87 utilize the often sparse vegetation of these sites. This response was very noticeable in parts of the foothills where high windswept suirimits were more extensive and thus more important to wintering sheep than on Nevis Mountain. On Nevis Mountain, the sheep spent much of their time on south or west facing slopes and ridges below 5,700 feet (1,737 m) altitude. The sheep remained on the lower south facing slopes to feed on the first green forage of early spring. As spring progressed, the sheep gradually spread out feeding on the weathered forage and new spring growth of higher altitudes and cooler exposures. During late May and early June most of the ewes moved on to steep rocky terrain to have their lambs. While ewes with newborn lambs tended to remain near steep, rocky terrain, those without formed groups that moved more freely over the slopes which were rapidly becoming more snow-free. During the summer the sheep grazed widely over their alpine habitat, generally at altitudes above 5,500 feet (1,676 m) but occasionally descending to treeline. The summer pattern of feeding, resting and nursing was interrupted by frequent visits to the mineral licks in the valley below. The licks were used most heavily in late spring and early fall. They were used by sheep of both sexes and almost 100 sheep were seen there at times, some from ranges at least 10 miles distant. Occasionally on the way to or from the licks, sheep visited the home ranges of adjacent bands, sometimes remaining for a week or more. 6.2.2 Foods and minerals Spring forage preferences as determined from five spring feeding sites in the Elymus-Agropyron community are presented in Table 21. In this table, the percentage frequency of occurrence refers to the percentage of plots in which a species occurred out of a total of 50 plots. The percent grazed refers to the percentage of plots in which a species was grazed out of the 88 total number in which it occurred. An importance index was calculated from the raw data by multiplying the number of plots in which a species was grazed by its frequency of occurrence and the results doubled to give an upper limit of 100. The species listed in Table 21 supported new spring growth in all plots where they occurred with the exception of Galium boreale which supported new growth in 10 out of the 15 plots.in which it occurred, and Rosa acicularis which supported no new growth. The lack of new spring growth may account in part for the low frequency of grazing on these species since the sheep appeared to be selecting for new green forage at the time. Table 21 shows that grasses, mainly Elymus innovatus, Agropyron subsecundum and Poa spp., occurred frequently and were grazed frequently, giving this forage class a combined importance rating (131.6) almost four and one half times greater than that for all other species recorded (29.7). Sedges were represented mainly by Kobresia myosuroides which had a grazing frequency of 83.5 percent but rated less than 1 in the importance index because it occurred in only 10 percent of the plots. Carex sp. which was grazed with a hundred percent frequency is not listed in Table 21 because it occurred in less than 10 percent of the plots. With the exception of Oxytropis sp., which was assigned an importance rating of 26, all forb species rate less than one in the importance index. Several species, including Achillea millefolium, with a 36 percent frequency of occurrence, were not grazed even though they occurred commonly. Forage species preferences were not measured specifically during the summer when the sheep grazed on a wide range of alpine plant communities as indicated in section 5.2.3. Observations indicate that grasses and sedges made up a major part of their diet with forbs being utilized to a 89 Table 21 Percent frequency of occurrence and spring grazing of plants in the Elymus-Agropyron community Importance Species Percent occurrence Percent grazed Index Grasses and sedges: 'bfordeae 100 98 . 98 Poa spp. 80 68.5 33.30 Festuca scabrella 14 22 0.28 Kobresia myosuroides 10 83.5 0.80 Forbs: Oxytropis sp. 52 29 26.0 Myosotis alpestris 40 13 0.80 Achillea millefolium 36 0 0 Galium boreale 30 6.5 0.3 Erigeron sp. 28 13.5 0.6 Zygadenus elegans 24 27.5 1.96 Gentiana sp. 24 0 0 Pedicularis sp. 24 0 0 Cerastium sp. 24 0 0 Mertensia paniculata 14 0 0 Antennaria sp. 14 0 0 Solidago multiradiata 12 0 0 Fragaria virginiana 10 0 0 Rumex acetosa 10 0 0 Saxifraga cernua 10 0 0 Shrubs: Rosa acicularis 14 ^Elymus innovatus and Agropyron subsecundum 90 lesser but significant extent. These forage classes were sought out by the sheep even when they fed on sites dominated by shrubs. Festuca scabrella, F. ovina and Poa spp. were grazed heavily by the sheep when feeding in the Festuca-Dryas community which they used frequently in summer. Often the sheep seemed to show little selectivity in their feeding except in their choice of plant communities, grazing randomly on whatever herbaceous vegetation was available. At other times, they showed a high degree of selectivity and this became more apparent as the end of the summer growing season approached. During an early snowstorm in August, the sheep pawed through 4 inches of snow to feed on low-growing herbaceous plants in the Elymus-Agropyron community, but did not feed on shrubs, arctic lupine or the coarse seedheads of lyme grass or bearded wheatgrass which protruded abundantly above the snow. In late summer and fall, the sheep browsed more frequently, mostly on the leaves of Salix glauca, and the leaves and fruits of Vaccinium uliginosium, V. Vitis-idaea and Ax'ctostaphylos uva-ursi. They were also • observed seeking out the flowering heads of certain plants such as Castillej a miniata and Potentilla fruticosa during this season. The rumen analysis results presented in Table 22 are from sheep collected on the winter range at Nevis Mountain and provide a measure of winter forage preferences. The first three rumen samples in the Table are from sheep killed in January, the last two from sheep killed in the fall. The sheep had been feeding mainly in the Elymus-Festuca and Festuca-Dryas plant communities when they were killed. The results in Table 22 confirm the importance of grasses in the sheeps' diet. Grasses and sedges averaged about 90 percent by volume of the material in the rumen samples and sedges probably represent a minor component 91 Table 22 Rumen sample analysis from 5 stone sheep collected on the winter range at Nevis Creek Rumen Sample *Av.% la lb 2 3 '•Av.% Food Item Est.% Value % Volume Volume Occurrence Grasses 6 Sedges: Festuca scabreUa 43.0 Poa sp. 16.0 Kobresia myosuroides 3.5 Festuca ovina 3.0 ^Hordeae 1.5 Carex sp. 0.5 Unidentified 30.0 Total 97.5 85.5 97 98.5 62 95 87.6 100 Forbs: Dryas integrifolia 0.5 1.5 tr 5.0 2.0 1.0 1.5 80 Leguminosae 0 0 0 0 tr 1.5 tr 40 Polemonium sp. 0 0 0 0 tr 0 tr 20 Silene acaulis 0 0 0 0 0 1.0 tr 20 Polygonum viviparum 0 0 0 tr tr 0 tr 60 Saxifraga tricuspidata 0 0 0 tr 0 0 tr 20 Unidentified tr tr tr tr tr 1.0 tr 100 Total 0.5 1.5 0.5 5.5 2.5 4.5 3.0 48.5 Shrubs: 2Salix spp. tr 1.5 tr tr 26.5 1.5 6.0 100 Vaccinium vitis-idea 0 0 2.5 0 5.5 0 1.5 40 Arctostaphylos uva-ursi 0 0 tr 0 1.5 0.5 0.5 60 Vaccinium uliginosum 0 tr tr 0 1.5 tr 0.5 80 Betula glandulosa tr tr tr tr 0 0 tr 60 Potentilla fruticosa tr tr 0 0 0 0 tr 40 Juniperus communis tr tr 0 0 0 0 tr 10 Unidentified tr tr tr tr tr tr tr 100 Total 0.5 2.0 3.0 0.5 35.0 2.5 8.5 86 " Average values determined from rumen samples lb to 5 ^Elymus innovatus and Agropyron sp. "Salix glauca, S_. polaris and S_. reticulata 92 since they were a minor component in the plant cover of the winter range communities. The results include the analysis of sample one by the point analysis method (la) as well as the water displacement method (lb). The point analysis results indicate that Festuca scabrella is an important forage species since it made up an estimated 43 percent or more by volume of the rumen content of a sheep killed while feeding in the Elymus~F_esJnjca plant community. Poa sp. also appears to be important but the significance of the results is questionable for all other species since the estimated percent volume was much less than that of the unidentifiable material. In addition to confirming that the sheep are primarily grazers, the rumen analysis results also confirms the relatively greater importance of shrubs in their fall diet. Grasses and sedges averaged 78.5 and shrubs 19 percent by volume of the fall rumen samples while these respective classes averaged 95.6 and 2 percent by volume of the winter rumen samples. When sheep visited the mineral licks, they ate alluvial soil from the creek bed and drank water seeping through fractured Buckinghorse shale which borders Nevis Creek. The analysis results of a soil sample from the lick and an unrelated control sample are presented in Appendix 5. The analysis results show the sample from the lick was lower in phosphorus and calcium and showed no significant difference in the amounts of ten other elements. However, the lick sample contained sodium in the amount of 78.9 lbs. per acre as opposed to only 37.2 lbs. per acre in the control sample. 6.2.3 Population structure The percentage composition of stone sheep populations as determined from classified counts from a major portion of the Northern Rocky Mountains and foothills are presented in Table 23. This table includes counts taken 93 in summer and winter during the period from January, 1969 to March, 1971. The Nevis Mountain count represents a mean total of the best counts determined for each age class at Nevis Mountain during the two summer and two winter periods of the study. All others represent single counts within which there was little or no duplication. The averages in Table 23 show that for every 100 ewes there were 63 lambs and 42 yearlings (n = 765). The results also indicate an average ratio of only 51 mature rams per hundred ewes (n = 591). The ratio of rams to ewes is too low and serves to show how difficult it is to get representative male:female ratios for sheep which segregate sexually (see section 6.3). In order to describe the ram segment of the population and provide more realistic ram:ewe ratios, the results of three selected counts are presented in Table 24. The counts in Table 24 were selected because they were the most extensive and inclusive in terms of ewe:ram ranges. Also, they were conducted by helicopter which permitted more complete coverage than ground counts and more accurate identification than counts from fixed-wing aircraft. In the results from the Muskwa-Prophet River count, Class III and Class IV rams, which were grouped initially, are separated on the basis of ratios determined for the other two counts in Table 24. According to the results in Table 24, there were 19 or 20 Class I, 25 or 26 Class II, 25 Class III and 10 or 11 Class IV rams for a total of about 80 adult rams per hundred adult ewes. Thus, the age class structure of rams was 24.5 percent Class I, 32 percent Class II, 30.5 percent Class III and 13 percent Class IV. The number of Class I rams seems dispropor• tionately high, especially in the Stone Mountain-Sentinel Range count. This is believed to be due largely to a poor representation of the last Table 23. Percentage composition of stone sheep populations in the northern Rocky Mountains. The actual number observed is shown in brackets beside the percent figure for each class. Unclass- Area Date Lambs Ewes Yearlings I II Ill ... IV ified Totals Muskwa- Prophet R. Jan. (Helicopter) 1969 24(65) 33(89) 11.5(31) 6(15) 10(27) 15.5(42) 0 (10) 279 Muskwa- Prophet R. Jan. (Ground) 1969 27(7) 31(10) 12.5(4) 3(1) 15(5) 15(5) 0 (8) 40 Nevis Creek- Richards Cr. (Helicopter July and ground) 1969 24.5(49) 28.5(57) 15.5(31) 8(16) 10.5(21) 9(18) 4(8) (75) 275 Nevis Creek- Besa R. Aug. (Ground) 1970 28.5(28) 46.5(46) 20(20) 4(4) 1(1) - - (7) 106 Tuchodi R. Mar. (Helicopter) 1971 29.5(12) 46.5(19) 22(9) 2.5(1) - - - - 41 Stone Mountain Mar. (Helicopter) 1971 19.5(36) 46(85) 17.5(32) 5.5(10) 5.5(10) 5.5(10) 1(2) (8) 193 Sentinel Range Mar. (Helicopter) 1971 23(26) 45(51) 18.5(21) 7(8) 2(2) 2.5(3) 2(2) (5) 118 Nevis Mtn. Av. (Helicopter 8 29(11) 48(19) 20.5(8) 2.5(1) 1.5(1) 0.5(1) 0.5(1) 42 Ground) Total No. (234) (376) (156) (56) (67) (79) (13) (113) 1094 Mean percentage 24 38 16 5.5 7 8 1.5 Mean No. per 53 42 14.5 18 21 4 100 ewes ^ Table 24. Rams per 100 ewes from selected classified counts (n = 194) Age Class Area Time I II III IV Totals Muskwa- Prophet Winter (Helicopter) 1968/69 18 30.5 33 14 95.5 Richards Creek- Nevis Creek Summer (Ground and 1969 28 37 31.5 14 110.5 Helicopter) Stone Mountain- Sentinel Range Winter (Helicopter) 1969/70 13 8.5 9 3.5 34.5 Mean Total 19.5 25.5 24.5 10.5 80.0 96 three age classes as discussed in Section 6.3. The sheep range on Nevis Mountain supported a small band of ewes and juvenile sheep totally about 50 animals. The results of classified counts from Nevis Mountain are presented in Table 25. The results in Table 25 represent the best classified count obtained for each class over the summer periods while the winter counts are from a single census made by helicopter in January, 1970, and March 1971. Since rams older than 2h years are only infrequent visitors to this range, they were not included in the results in Table 25. According to the results in Table 25 there was an average of 61 lambs and 43 yearlings per hundred ewes. This compares closely with the average lamb:ewe (63:100) and yearling:ewe (42:100) ratios obtained for counts taken over a greater area of the Northern Rocky Mountains (see Table 23). 6.2.4 Productivity The ratio of lambs to ewes from early summer counts in the study area provides a relative measure of productivity (Table 26). The results in Table 26 show an average observed lamb:ewe ratio of 74:100 indicating a high birthrate and low mortality in the first few weeks of life. Calculated ewe:lamb ratios were determined by subtracting 20 percent 2-year old females from the total mature females on the assumption that ewes bear their first young at age three. The number of two-year old ewes was assumed to be equal to the number of two-year old males as determined in section 6.2.3. The calculated lamb:ewe ratios which averaged 91:100 seem high, especially since some individually recognized ewes older than two years either did not bear young or lost them soon after birth. It is possible that the estimated number of two-year old ewes is too high. It is Table 25 Percentage composition of the ewe-juvenile band at Nevis Mountain. The actual number counted is shown in brackets beside the percentage for each class. Age and Sex Classes Date Lambs Ewes Yearlings Rams I Total Summer/69 32(9) 46.5(13) 18(5) 3.5(1) 28 Summer/70 29(12) 44(18) 22(9) 5(2) 41 Mean summer ~ST~" count 45 20 4 Winter/ 1969- 70 24.5(11) 51(23) 22(10) 2.5(1) 45 Winter 1970- 71 30(12) 50(20) 20(8) 0(0) 40 50,5 21 1 Mean Winter 27 count Mean Total 29(11) 48(19) 20.5(8) 2.5(1) 39 98 Table 26 Lamb:ewe ratios from early summer counts in the Nevis Creek area. Calculated Observed ratio Area Date ratio Nevis Mountain 1969 76/100 95/100 Nevis Mountain 1970 70/100 87.6/100 *Richards Creek- Nevis Creek 1969 86/100 107.5/100 "Besa River- Nevis Creek 1970 63.5/100 79,5/100 Average 74/100 91/100 " Ratios from single counts with no duplication 99 also possible that ewe-juvenile groups were more readily seen and counted than the smaller and less active groups without lambSj.or single ewes. This is suggested for the Richards Creek-Nevis Creek count by the high observed yearling:ewe ratio (54:100). 6.2.5 Juvenile and adult mortality The change in lamb:ewe ratios and between yearling:ewe ratios through time provides a relative measure of juvenile mortality. The number of young sheep born at Nevis Mountain in the spring of 1969 per hundred ewes is shown through successive seasons to March, 1971 in Table 27. Table 27 Seasonal changes in numbers per hundred ewes of young sheep born at Nevis Mountain in 1969. Figures in brackets represent percent change. e tal *Ratif? o Year Summer Fall Winter Chang^° e Lamb:ewe 1969/70 76:100 69:100(-9) 47.5:100(-31) -40 Yearling:ewe 1970/71 46.5:100(-2) 43:100(-7.5) 41:100(-4.5) -14% Total -54% The results in Table 27 show a high mortality rate in the first year of life with most of it occurring early in the first winter. Mortality decreased sharply after the first year of life, totalling only 14 percent in the period from May, 1970 to March, 1971. The classification of adult males into four age classes provides a measure of adult mortality and survivorship for this segment of the 100 101 population. Figure 19 represents a survivorship curve for stone rams in the northern Rocky Mountains. It was derived from data presented in section 6.2.3(a). Figure 19 graphically illustrates the period of high juvenile mortality discussed earlier. This is followed by a period of low mortality during adult life to about 8 or 10 years after which a second period of high mortality occurs. The apparent decline in survivorship between age Class I and age Class II rams is thought to represent mainly a low count in the last three age classes. This is discussed further in section 6.3. The expected survivorship curve, assuming representative counts for all age classes, is also shown in Figure 19.. 6.2.6 Mortality factors Although little direct information was obtained on causes of mortality, sufficient data and observations were obtained to discuss the topic generally under the following headings: (a) Competition for forage As is true for most stone sheep habitat, domestic livestock were not present on the alpine sheep range at Nevis Mountain. Observations indicate that competition for forage between sheep and other wild ungulates is minimal at Nevis Mountain and over most of the foothills area. Although moose were commonly seen above treeline in the northern foothills, they were predominantly browsers, feeding mainly on shrubs a meter or more in height. Deer are present only in limited numbers in the foothills and this species was seldom seen above treeline. Caribou were abundant throughout the area, however, and this species commonly used the alpine habitat. Rumen samples collected from two caribou in January, 1969, were analyzed by the water displacement method to determine if there was a significant overlap 102 in the forage classes used by this species and those used by sheep. The results indicated that cryptogams, which made up 32 and 66 percent of the two samples were more important in the winter diet of the caribou. Grasses and sedges were also important, however, totalling 44 and 30.5 percent by volume of the two rumen samples. In spite of this overlap, competition for forage between sheep and caribou is believed to be minimal since obser• vations consistently indicated that these species favour different parts of the alpine zone. In winter, caribou were often seen pawing through several inches of snow on high plateaus or cool northern or eastern exposures to feed while sheep grazed on adjacent snow-free southern and western exposures. Elk were rare at Nevis Creek but this species is locally abundant in the Prophet, Muskwa^Tuchodi and Gathto drainages to the north where they appear to have been increasing in recent years. In areas where they are locally abundant, elk were using the alpine habitat and they appeared to favour the warm southern and western exposures that sheep depend on for winter range. Intraspecific competition for forage during severe winter weather is probably more important as a cause of mortality. Four juvenile sheep were found dead on the winter range during this study. Condition of the bone marrow indicated that three of these were suffering from severe malnutrition at the time of death, (b) Disease and parasites All seven of the sheep, ranging in age from 2^ to 9h years, which were autopsied during the study showed evidence of lungworm infection. In all cases, the tissue in the region of the diaphragmatic lobe had a mottled appearance as a result of few to many fibrous lesions indicating long-standing infection (Bandy, pers. comm.). Microscopic examination of the necrotic 103 tissue revealed few to numerous lungworm (Protostrongylus sp.) adults and larvae in the parenchymal tissue. The parasite has been tentatively identified as P. stilesi (Adams, Department of Zoology, University of British Columbia, Vancouver, 1971). Certain species of land snails belonging to the genera Helicella, Oreohelix, Pupilla, Vertigo, and Valloria are known to serve as intermediate hosts for Protostrongylus lungworms (Buechner, 1960). At Nevis Mountain, an unknown species of small land snail was very abundant in the Elymus- Agropyron community which the sheep grazed almost to ground level. Five of the seven sheep autopsied and the remains of several others killed by hunters or found dead on the range showed symptoms of actinomycosis. The disease, commonly called lumpy jaw, is produced as a result of infection by the bacterium Actinomyces (Cowan, 1951). The infected animals had enlarged jaw bones, usually attended by chronic infection of tooth sockets as evidenced by loose or missing teeth. In spite of heavy lungworm infestation and diseased jaws, all of the animals autopsied in the field had good fat reserves, few external parasites and otherwise appeared in good health. Occasionally, during the study, sheep were observed in poor condition. These animals usually had a severe cough suggesting heavy lungworm infestation. Also, it was noticed that, during a severe chase, big, old rams could not keep up to younger animals and were the first to show signs of respiratory distress. This may be due to lungworm infestation which would reduce the resilience and hence the tidal volume of the lungs as suggested by Geist (1971). However, these observations were made during mid-winter when the old rams were probably in a relatively more weakened condition from the rut. On the whole, few sheep seen during this study were unhealthy or in poor condition. 104 (c) Injury During the study, several sheep were seen with leg injuries serious enough to cause a limp and impede the animals movement. Such injuries may be due to a fall. Although sheep which lose their footing when climbing are usually able to avoid a fall by jumping to safer footing, this is not always the case. On July 31, 1970, a young lamb at Nevis Creek slipped and fell approximately 30 feet onto a rocky streambed. In this instance, the animal landed on its feet and, though shaken momentarily, it did not appear to suffer serious injury. The sheep are more susceptible to injury when panicked. In one instance, a ram received a serious cut on its haunch when it struck a sharp rock while fleeing a low-flying aircraft. Undoubtedly some sheep die from accidental injuries either directly or indirectly because they are more susceptible to predation, but on the whole this appears to be a minor cause of mortality. (d) Predation Of the several predators in the area, the wolf (Canis lupus) is the most significant predator of sheep. Wolves were common in the northern foothills area during this study and, according to local residents, their numbers had increased in recent years. Evidence of wolves was not uncommon in the alpine, especially in winter when wolves were seen in close proximity to sheep on several occasions. However, caribou and moose were also present on the alpine ranges and these appeared to be the most important prey species of the wolf as a number of kills were sighted during the study period. No sheep kills were observed though the stomach of a wolf shot by hunters in early August contained the remains of a lamb. It seems worth noting that all of the wolf dens observed during this study were at low elevation, adjacent to beaver ponds or to mineral licks 105 frequented by moose and caribou. Although evidence is lacking, it seems doubtful that wolves were significantly influencing stone sheep populations in the northern foothills during this study. Both golden eagles (Aquila chrysaetas) and bald eagles (Haliaeetus leucocephalus) were present in the study area. Although eagles were seen diving at young sheep on several occasions, in a few cases quite persistently, no successful attack was witnessed. The sheep were alerted by the nearby presence of an eagle, particularly when the lambs were very young. When an attack occurred, the ewe stood over or close to the lamb and watched the eagle closely. In a few cases, ewes jumped at a diving eagle as if to strike it. Although they even made dives at yearlings on occasion, low- flying eagles frequently ignored the sheep altogether. Coyotes were present but not numerous and in the only attack witnessed, a ewe and 3 months old lamb easily outdistanced the predator by running up a steep slope. Black bears, grizzlies, lynx and wolverine were also present in the area but they too appeared unimportant as predators of sheep. In addition to the sheep remains found in the stomach of a wolf, scats of wolves, bears and wolverines were seen, which appeared to contain sheep hair. However, this is not necessarily evidence of a kill. Two incidences during this study served to show how quickly and efficiently predators can locate the carcass of dead animals. In one case, three black bears appeared at the scene of a sheep kill within 48 hours, one within 10 hours, though none had been seen on the alpine sheep ranges for almost two months. In another, the carcass of a sheep shot during a snowstorm and covered with a clean canvass tarp and several inches of snow was located by wolves within a few days. The wolves, which had been hunting in the 106 valley when the sheep was shot, located the carcass in the alpine during a period with little wind and temperatures well below zero. (e) Hunting Hunting is an important source of mortality, at least in the older age class ram segment of the population. There is a long history of guided hunting and, more recently, resident hunters have begun to exploit sheep populations in the northern Rockies. Although guides and other local residents report that rams smaller than 3/4 curl (age class III) and, occasionally, ewes and juvenile sheep are shot, guided trophy hunters have always selected the older, full curl or larger rams* . Recent hunting regulations have • been -^snacted—fee- restrict the kill to this segment of the population. In a guide's area near Nevis Creek, 142 rams, most of which were full curl or larger, were harvested by hunters in the five-year period prior to 1972 (Harper, pers. comm. 1972). The estimated mean age of the rams was 9.13 years, the youngest being 5^ years and the oldest 13h years of age (n = 78). 6.3 Discussion The movements and distribution of the sheep at Nevis Mountain were dictated by their needs, by the physical limitations of their environment and by tradition. In winter, unfavourable snow depths caused the sheep to concentrate on exposed sunny and windswept slopes representing less than 20 percent of their total productive habitat. During critical periods in the winter and again in early spring, the sheep relied heavily on forage from the Elvmus-Agropyron community. This community, which has developed on calcareous soils of warm southern exposures, occupies less than 20 percent of the winter range area. In summer the sheep ranged widely, making full 107 use of the varied habitats available to them. Mineral licks, in which sodium appears to be the attractive element, were visited frequently from late spring to early fall. Sodium is considered the attractive element in the predominance of studies which have analyzed mineral licks in North America (Hebert, 1967). The function and importance of mineral licks is uncertain, though it is generally assumed that they supplement a dietary or physiological need (Cowan and Brink, 1949). Whatever their importance otherwise, their attraction is strong and they have a major influence on the movement and distribution of sheep in certain seasons. They cause the sheep to concentrate and to travel far from escape terrain where they are more susceptible to predation. Through them traditional routes are main• tained, providing a link between the home ranges of different bands of sheep. They may also be important as a source of transfer of disease or parasites (Green, 1949) or as social centres (Knight and Mudge, 1967). According to the results of classified counts, stone sheep populations in the fall averaged about 35 percent ewes and 27 percent rams 2\ years or older, 24 percent lambs and 14 percent yearlings. About three or four percent of the population, or twelve percent of the mature rams were 3/4 curl rams or larger and therefore legal game under existing hunting regulations. Only three or four percent of these, or one or two percent of the total population were full curl or larger rams which are so highly prized as trophy animals. As indicated in section 6.2 the classified counts are subject to several possible sources of error, of which duplication is one. This source of error is expected to be greater in counts conducted on the ground, such as the summer counts at Nevis Creek, since groups of sheep are constantly moving and exchange constantly occurs between groups. 108 However, it appears to be a minor source of error, since the averaged results of counts from Nevis Mountain are closely comparable with the averaged results of all counts combined. It is usually necessary to conduct counts over an extensive area to get a representative sample of the population. The sheep not only segregate sexually into ram-ewe groups, but juveniles occasionally form groups and ewes without lambs tend to separate from ewe-juvenile groups shortly after the lambing season. While time limits the size of area that can be covered on foot or horseback, aerial counts are more subject to errors in identification especially where fixed-wing aircraft are used. The high variance in age classes of rams and between ram:ewe ratios in the different counts indicates how difficult it is to obtain representative counts of the ram segment of the population. Rams tend to occur in smaller groups and to favour different terrain as well as different areas than ewe-juvenile groups. Unfortunately, it was not possible to conduct counts during the rut when both sexes occur together. The number of Class I rams in Table 24 is thought to be too high in relation to the last three age classes. According to Leopold's breeding table (1933) for animals which first bear young at three years.and bear one young per year, 23 percent of the males will be two years old. This compares closely with the average results in Table 24 which shows 24.5 percent of the mature rams in this age class. However, Leopold's breeding table is based on the assumption that all individuals survive so the number in natural population would be somewhat lower than 23 percent. The high proportion of Class I rams is probably due to a poor representation of rams in the last three age classes. This may be due to a low count of these animals as seems apparent in the Stone Mountain-Sentinel Range count. However, it is also due partly to hunting since most populations in the 109 northern foothills are subject to trophy hunting which selects strongly for the largest horned and, therefore, usually the oldest animals. According to the results in Table 24, there was an average of 80 mature rams per 100 mature ewes in these populations. The oldest age Class IV, which comprised only 10 percent of the ram population, was the most poorly represented in view of the large spread in years which it represents. It is generally thought that the sex ratio in natural unhunted populations of mountain sheep is about equal (Buechner, 1960 and Geist, 1971). Geist (1971) found a mature ram:ewe ratio of 88:100 at Gladys Lake in the .Cassiars. The adult ram population in Geist's stone sheep study area averaged 24 percent Class IV rams. Hunting pressure on the populations in the northern Rockies is thought to be greater than it was on the populations studied by Geist in the Cassiars in 1961-62. As indicated in Section 6.2.4 the calculated lamb:ewe ratios shown in Table 26 seem high, particularly since some ewes older than 2 years did not bear young. It is possible that the observed ratios were too high initially because ewe-juvenile groups were more readily seen and counted than ewes without lambs. Although this is suggested in the Richards Creek-Nevis Creek count by the high yearling:ewe ratio (54:100), it is not thought to be so in the other counts. It is more probable that the estimate of 20 percent 2-year old ewes used in deriving the calculated ratios is too high. However, it is possible that some two-year old ewes gave birth or that some ewes bore twins. Since two-year old ewes cannot be recognized with any degree of certainty in the field, there was no way of knowing if any bore young. Apparently yearling sheep will breed successfully under conditions of excellent nutrition. Woodgerd (1964 and Buechner (1960) cite instances of successful breeding by yearling bighorn 110 ewes. Although twinning is apparently uncommon in natural sheep populations, Buechner (1960) cites several cases of twinning in Rocky Mountain bighorn sheep. Spalding (1966) found that four out of eleven California bighorn (Ovis canadensis californiana) killed on a road in southern British Columbia were carrying twins. Although ewes with more than one lamb and groups with more lambs than ewes were seen on several occasions, no positive evidence of twinning was obtained during this study in the northern Rockies. Estimates of mortality for juvenile sheep were derived from relative changes through time in the numbers of a single cohort group and is subject to fewer sources of error than estimates derived from differences in numners of different age class animals. These estimates are expected to be low if anything, since they are based on the assumption of no mortality of adult ewes. Although no estimate of mortality is available for adult ewes in this population, it is expected that some took place over the two year period. Geist (1971) estimated an average mortality rate of about 11.7 percent and 20 percent respectively for adult ewes in bighorn populations studied by Hansen (1967) and Wishart (1958). Interspecific competition for forage appeared to be minimal at Nevis Creek, but it may occur with elk on critical sheep winter range in other parts of the northern foothills. Although elk are commonly browsers, Cowan (19173) found the food habits of elk in the National Parks cut right across those of other ungulate species present, including sheep. On the Nevis Creek sheep range, intraspecific competition during periods of deep snow or severe icing conditions probably contributes more significantly to mortality. Lungworm and actinomycosis appear to be common diseases of stone sheep in the study area. Lungworms are frequently the cause of Ill debility and death in mountain sheep either directly or by weakening the host so that it is susceptible to accidental predation, malnutrition or disease of the septicemic or actinomycotic groups (Cowan, 1944). Actinomycosis contributes to mortality through malnutrition because of its effect on jawbones and teeth. Cowan (1940) refers to stone sheep shot in early autumn which were in poor and weakened condition apparently as the direct result of the loss of their teeth. He suggests that the maximum age in sheep is limited largely by the life span of their teeth. Certainly the teeth of some of the diseased sheep at Nevis Creek were in very poor condition. There are references to actinomycosis in stone sheep populations from some very early records (Blair, 1907 and House, 1909). According to Cowan (pers. comm.), this disease, now uncommon in British Columbia bighorn populations, was very common in the sheep at Banff when he studied populations there in the 1940's. Wolves appear to be the most serious predator of sheep in the northern foothills but casual observations suggest that they are probably not an important limiting factor on these populations. During his studies in Jasper National Park, Cowan (1947b) found that wolves not only failed to remove the net increment of,their ungulate prey populations, they failed even to remove the diseased and injured animals. However, dall sheep populations studied by Murie (1944) were depressed by wolf predation in a complex situation dependent on concurrent changes in wolf and sheep populations. A decline in sheep numbers due to severe snow conditions and a corresponding increase in wolf numbers led to the situation where wolves were able to cause a decrease in the surviving population, mainly by preying on the old, the diseased, and the lambs during the first winter. Pimlot (1967) suggests that the interaction of the variables of 112 predation and the different environmental variables encountered produce such complexities that few generalizations are possible on the influence of predation by wolves on prey populations. Eagles did not appear to be a significant predator on young sheep in the study area. Although there are several records of successful predation on native sheep by eagles, no studies suggest that such predation has an important limiting effect on the population'. 113 7. GENE PAL DISCUSSION AND CONCLUSIONS Diversity characterizes the Nevis Creek study area. Physiographic, climatic and edaphic diversity is reflected by the vegetation which presents a complex, heterogeneous pattern locally to a degree seldom observed in more southern latitudes. This complex pattern appears to be duplicated repetitively throughout the northern foothills, however, so the data presented here should have a regional as well as a local applicability. Climate, like most other variables, is strongly influenced by topography. The important contribution of local climate to vegetative diversity is visibly apparent in striking floristic differences on different slopes and exposures. Thus the contrast between the productive Elymus-Agropyron community on steep southern exposures and the relatively unproductive, tundra• like cryptogam - Salix community on directly opposing slopes. Exposed alpine ridges from treeline to summit elevations support plant communities character• ized by a sparse cover of low-growing forbs, grasses and sedges which have a high degree of tolerance to dessication, wind breakage and low soil temperatures. In contrast, shrubs and even low-growing trees have established far above treeline in protected places where accumulated snow provides a blanket of protection. Soils have contributed notably to floristic diversity in the alpine zone where they have developed in highly stratified contrasting bedrock formations disturbed little by glaciation. Dystric Brunisols, Gleysols and Regosols developed in acidic parent materials prevail. Although these soils support a range of plant communities, they are limited by associated low temperatures, extreme acidity and saturated conditions, and the plant 114 communities they support reflect this both floristically and by low product• ivity. Eutric Brunisols and Chernozem-like soils on basic geologic materials of southern exposures support productive grassland communities which yield high quality forage. Stability is also characteristic of the vegetation in the study area. Even the widespread seres below treeline are characterized by slow rates of succession while the alpine plant communities, largely free of a fire history, are extremely stable climax or disclimax communities. Trends indicating long-term changes are apparent, however, and are significant here because they are inclined to reduce the available habitat for sheep. Although the slow, cumulative spread of shrubs onto grasslands is due, in part, to self-induced microclimatic changes, the widespread and persistent nature of this trend and of the poludification of alpine communities on cool exposures by mosses and lichens suggests a response to more general climatic changes. Such trends may be due to long-term climatic changes. North Pacific North America has undergone three major climatic intervals since the Pleistocene period of glaciation, the third and present of which has been marked by cooling and rising humidity (Heusser, 1960). On the other hand, these trends may be due to relatively short-term climatic shifts. Climatologists now recognize that relatively short-term climatic shifts sufficient to have influenced ecological events have occurred within the past century and that for many countries this shift has been particularly significant in the last decade (Lamb, 1969). Recent climatic shifts have been suggested as an explanation for the advance of aspen forest onto grasslands in northern and central British Columbia (Brink and Farstad, 1949) and for the advance of subalpine forest onto alpine heath in the Garibaldi area (Brink, 1959). Light glaciation in this area suggests the possibility that refugia 115 may have existed in the Northern foothills during one or more of the Pleistocene periods. This, in turn, suggests a possible explanation for the origin and distribution of stone sheep. So far there has been no satisfactory explanation for the origin and distribution of stonei which differs significantly from dalli to have required at least a period of separation of the original stocks (Cowan, pers. comm., 1970). The view that plant and animal species have been able to survive throughout long glacial periods in restricted ice-free areas or closed refugia is supported by recent evidence from Alaska and Iceland (Lindroth, 1970). Diversity and stability appear to be important environmental features of stone sheep habitat in the Nevis Creek study area. The juxtaposition of diverse habitats largely enables the sheep to meet their needs in an often harsh alpine environment of limited extent. In keeping with their more stable environment where changes are due mainly to long-term events, sheep populations in this area appear to fluctuate less violently than bighorn populations further south. Many bighorn populations in North America have suffered serious die- offs which have been linked to a lungworm-pneumonia disease complex in which heavy lungworm infestation is considered to be a predisposing agent for pneumonia (Buechner, 1960). Buechner has suggested that many bighorn popul• ations are controlled by such die-offs but a number of attendant environmental factors preceding the disease complex may actually be the causal agent. Recent bighorn die-offs in southern British Columbia affected populations dependent on low elevation grasslands for winter habitat. The grasslands, expanded by widespread fires in the past, were shrinking due to forest succession. Overgrazing by domestic livestock and by game and severe winter conditions coincident with shrinking winter ranges is believes to have 116 lowered the animals' resistance and triggered the die-off (Bandy, 1968). Stelfox (1971) reports that bighorn sheep populations in the Canadian Rockies were drastically reduced between 1937 and 1949 by a series of die-offs which were attributed to lungworm-pneumonia disease, deteriorated ranges, heavy elk and livestock competition, shrinking winter ranges due to forest succession and three severe winters between 1946 and 1949. Although local residents reported heavy losses in stone sheep populations during severe winters with deep snow, there have been no reports which suggest a major die- off such as occur in bighorn populations. It appears that enzootic die-offs are not a feature of the sheep populations in this relatively pristine, , stable environment even though the necessary disease organisms are present. The sheep at Nevis Creek were mainly dependent on herbaceous vegetation from the relatively stable alpine communities for their protein and carbo• hydrate requirements. Serai grasslands tend to be short-lived and largely unsuitable for wintering sheep as they are rapidly invaded by shrubs which reduce the herbaceous ground cover and cause drifting snow to accumulate. The fortuitous combination of several environmental variables provided critical winter range on exposed south and west facing slopes. Here, Chernozem-like soils and Eutric Brunisols having the favourable soil char• acteristics of moderately coarse texture, moderate soil reaction, good drainage and an adequate nutrient status have combined with a favourable microclimate to support the most productive and nutritious alpine forage. Furthermore, the forage is largely available for wintering sheep because of reduced snow depths, and though forage productivity is typically low compared with lower altitudes, quality is high and is maintained in the cured stage by sharp fall frosts and the persistent winter cold. Although their habitat includes a broad spectrum of necessary elements, 117 all of which are important, the Elymus-Agropyron.community is particularly significant. This plant community, which occupied less than twenty percent of the winter range and four percent of the total productive habitat, provided almost sixty percent of the forage for wintering sheep. Competition for forage was minimal in the relatively undisturbed sheep habitat at Nevis Creek, but it may occur with elk on critical sheep winter ranges in other parts of the northern foothills. In these areas, elk populations appear to be expanding in the wake of repeated fires. Fire has produced short-term benefits for several ungulate species, including sheep^ in the northern foothills area. However, maintenance of serai vegetation by repeated burning should be approached with caution and site-specific information. The long-term effects on the habitat, the chance of producing unfavourable seres and the differential effects on all species should be considered. Fire has been shown to reduce the quality and quantity of habitat for caribou for long periods of time (Scotter, 1964), and has been correlated with population declines of this species throughout most of British Columbia (Edwards, 1954). The alpine habitat of stone sheep, largely protected by isolation in the past, is rapidly becoming exposed to the influence of man with accelerated development of the north. As low productivity rates and slow succession rates emphasize, alpine ecosystems are sensitive and slow to recover from abuse, factors that should be considered prior to any interference by man. Major changes to or destruction of their habitat could seriously reduce stone sheep populations dependent on it, possibly by triggering enzootic die-offs due to lungworm-pneumonia disease complex as in bighorn populations of more southern latitudes. 8. LITERATURE CITED Association of Official Agricultural Chemists. 1960. Official methods of analysis. 10th edition. (Washington, D.C.) Bandy, P.J. 1968. Rocky Mountain bighorn sheep losses in the east Kootenay region of B.C. 1965-1967. A paper presented to the Northwest Section, the Wildlife Soc. Univ. of Alta. Edmonton (Mar.23). Blair, W.R. 1907. Actinomycosis in the black mountain sheep. N.Y. Zool. Soc. Ann. Rept. 11:132 pp. Bowden, G. and P.H. Pearse. 1968. Nonresident big game hunting and the guiding industry in British Columbia; an economic study. Dept. of Recreation and Conservation (Victoria). 72pp. Brink, V.C. and L. Farstad. 1949. Forest advance in north and central British Columbia. The Can. Field Naturalist. Jan-Feb. Brink, V.C. 1959. A directional change in the subalpine forest - heath ecotone in Garibaldi Park, British Columbia. Ecology, V.40 No. 1 pp. 10-15. Brink, V.C, A. Luckhurst and D. Morrison. 1972. Productivity estimates from alpine tundra in British Columbia. Can.J.PI.Sci. V.52, No. 3 (Ottawa). Brown, Dorothy. 1954. Methods of surveying and measuring vegetation. Commonwealth Agric. Bureaux Farnham Royal, Bucks., England. 223 pp. Buechner, H.K. 1960. The bighorn sheep in the United States, its past, present and future. Wildl. Monogr. 4:1-174. Canada Department of Agriculture. 1970. The system of soil classification for Canada (Ottawa). Canada Department of Transport, Meteorological Branch. 1965. Temperature normals for British Columbia. Climatic data sheet No. 3-65 (Toronto). 1967. Temperature and precipitation tables for British Columbia. (Toronto). 1968a. Climatic Normals Vol. 5. Wind (Toronto). 1968b. Climatic Normals. Vol. 6. Frost data (Toronto). 1970. Monthly records (Toronto). Chamrad, A.D. and T.W. Box. 1964. A point-frame for sampling rumen contents. J.Wildl. Mgmt. 28(3): 473-477. 119 Chapman, J.D. 1952. The climate of British Columbia. Paper presented at 5th British Columbia Nat. Res. Conf. Univ. of British Columbia (Feb. 27). Cowan, I.MoT. 1940. Distribution and variation in the native sheep of North America. Am. Midi. Nat. 24(3): 505-580. 1944. Report of wildlife studies in Jasper, Banff and Yoho National Parks and parasites diseases and injuries of game animals in the Rocky Mountain National Parks of Canada. Wildl. Serv. Ottawa. 83pp. (mimeo). 1947. Range competition between mule deer, bighorn sheep and elk in Jasper Park, Alberta. Trans. N. Am. Wildl. Conf. 12:223-227. 1947b. The timber wolf in the Rocky Mountain National Parks of Canada. Can.J. Res. 25: 139-174. , and V.C. Brink. 1949. Natural game licks in the Rocky Mountain National Parks of Canada. J. of Mammal. 30(4): 379-387. , and C.J. Guiget. 1965. The mammals of British Columbia. Prov. Mus. Hndbk. No. 11 (Victoria). 1951. The diseases and parasites of big game mammals of western Canada. Proc. Ann. Game Cons. B.C. Game Dept. 5:37-64. Daubenmire, R.F. 1968. Plant communities, a textbook of plant synecology. Harper and Row Publ. N.Y. 300 pp. Daubenmire, R.F. 1959. A canopy coverage method of vegetational analysis. Northwest Sci. 33(1): 43-64. Demarchi, D.A. 1970. Effects of grazing on the botanical and chemical composition of range vegetation in the lower Chilcotin River region, British Columbia, M.Sc. thesis, Library, Univ. of Idaho. Demarchi, R.A. 1968. Chemical composition of bighorn winter forages. J. Range Mgmt. 21(6):385-588. Dirschl, H.J. 1963. Food habits of the pronghorn in Saskatchewan. J. Wildl. Mgmt. 27(1): 81-93. Edwards, R.Y. 1954. Fire and the decline of a mountain caribou herd. J. Wildl. Mgmt. 18: 521-526. Geist, V. 1968. On the interrelation of external appearance, social behaviour and social structure of mountain sheep. Zs. Tierpsychol. 25: 199-215. 1971. Mountain sheep. A study in behaviour and evolution. Univ. of Chicago Press. 383 pp. 120 Green, H.U. 1949. The bighorn sheep of Banff National Park. Natnl. Parks Hist. Sites Serv. Dev. Serv. branch (Ottawa). 53pp. Godfrey, W.E. 1966. The birds of Canada. National mus. of Can. Bull. Series No. 73. 428pp. Hansen, G. 1967. Bighorn sheep populations of the Desert Game Range. J. Wildl. Mgmt. 31: 693-706. Harper, F.E. 1969. Effects of certain climatic factors on the productivity and availability of forages on the Ashnola bighorn winter ranges. M.Sc. thesis, Library, U.B.C. Harper, F.E. 1972. Personal communication. Regional Wildlife Biologist, B.C. Fish and Wildlife Branch, Fort St. John, B.C. Hebert, D.M. 1967. Natural salt licks as a part of the ecology of the mountain goat. M.Sc. thesis, Library, U.B.C. Heusser, C.J. 1960. Late Pleistocene environments of north Pacific North America. Am. Geog. Soc. Spec. Publ. No. 35. Hitchcock, C.L., A. Cronquist, M. Ownbey and D.W. Thompson. 1955, 1959, 1961, 1964, 1969. Vascular plants of the pacific northwest. Univ. of Wash. Publ. in Biology. 5 vols. Univ . of Wash. Press (Seattle). Holland, S.S. 1964. . Landforms of British Columbia, a physiographic outline. Bull. 48, B.C. Dept. Mines and Natural Resources (Victoria). House, E.J. 1909. A hunters campfires. Harper and Bros. pub. N.Y. and London. Hubbard, W.A. 1955. The grasses of British Columbia. Prov. Mus. Hndbk. No..9 (Victoria). Hulten, E. 1968. Flora of Alaska and neighbouring territories. Stanford Univ. Press (Calif.) Johnson, A., L.M. Bezeau and S. Smoliak. 1968. Chemical composition and in vitro digestibility of Alpine tundra plants. J. Wildl. Mgmt. 32(4): 773-777. Knight, R.R. and M.R. Mudge. 1967. Characteristics of some natural licks in the Sun River area, Montana. J. Wildl. Mgmt. 31(2):293-299. Leopold, A. 1933. Game Management. Charles Scribners Sons, N.Y. Lindroth, CH. 1970. Survival of animals and plants on ice-free refugia during the Pleistocine glaciations. Lord, T.M. and A. McLean. 1969. Aerial photo interpretation on British Columbia rangelands. J. Range Mgmt. 22(1): 3-9. 121 Lord, T.M. 1972. Personal communication. Pedologist, Canada Agriculture, Vancouver, B.C. Mathews, W.H. 1971. Personal communication. Professor, Department of Geology, University of British Columbia (Vancouver). McLearn, F.H. and E.D. Kindle. 1951. Geology of north-eastern British Columbia. Geol. Surb. Canada Mem. 259 (Ottawa). Moss, E.H. 1959. Flora of Alberta. Univ. of Toronto Press. (Toronto). Murie, A. 1944. The wolves of Mount McKinley Fauna Series No. 5 (Washington). National Research Council, U.S.A. 1964. Committee on animal nutrition. Nutrient requirements of domestic animals. No. 5, Nutrient requirements of sheep. (Washington). National Soil Survey Committee of Canada. 1968. Proceedings of the seventh meeting held at Edmonton, Alberta (Ottawa). Pelletier, B.R. and D.F. Stott. 1963. Trutch map-area, British Columbia. Geol. Surv. Canada, Paper 63-10. (Ottawa). Pelletier, B.R. 1964. Triassic stratigraphy of the Rocky Mountain foothills between Peace and Muskwa Rivers, northeastern British Columbia. Dept. of Mines and Tech. Surveys (Ottawa). Pimlott, D.H. 1967. Wolf predation and ungulate populations. Amer. Zoologist 7: 267-268. Poulton, CE. and E.S. Tisdale. 1961. A quantitative-method for the description and classification of range vegetation. J. Range Mgmt. 14(1): 13-21. Rowe, J.S. 1959. Forest regions of Canada Bull 123. Can. Dept. Northern Affairs and Natural Resources (Ottawa). Schofield, W.B. 1969. Some common mosses of British Columbia. Prov. Mus. Hndbk. No. 28 (Victoria). Scotter, G.W. 1964. Effects of forest fires on the winter range of barren ground caribou in northern Saskatchewan. Can.. Wildl. Serv. Wildl. Mgmt. Bull. Series 1, No. 18 (Ottawa). Spalding, D.J. 1966. Twinning in bighorn sheep. J. Wildl. Mgmt. 30: 207-208. Stelfox, J.C. 1971. Bighorn sheep in the Canadian Rockies. A History 1800- 1970. The Can. Field Naturalist 85(2): 101-122. Vince, G, 1970. Personal communication. Hunting guide and outfitter, Fort. St. John, BC. Willard, B.E. and Marr, J.W. 1971. Recovery of alpine tundra under protection after damage by human activities in the Rocky Mountains of Colorado. 122 Biol. Conserv. 3: 181-190. Wishart, W.D. 1958. The bighorn sheep of the Bighorn Sheep River Valley. M.Sc. thesis. Library, Univ. of Alberta (Edmonton). Wang, J.Y. 1963. Agricultural meteorology. Pacemaker Press, LaCross, Wise. 693pp. APPENDIX 1 Scientific and ccmmon names and authorities for plant species identified in the Nevis Creek area. References include: Hitchcock et al (1955, 1959, 1961, 1964,1969), Hubbard (1969), Hulten (1968), Moss (1959) and Schofield (1969). Specimens are available at the University of British Columbia herbarium for all species with a collection number. 124 Scientific and common names and authorities for plant species identified in the Nevis Creek study area. Grasses and sedges: G52 Agropyron subsecundum Link Hitchc. bearded wheatgrass G53 Agropyron violaceum (Hornem.) Lange wheatgrass Ggb22 Arctagrostis latifolia (R.Br.) Griseb. polar grass G7 Bromus Pumpellianus Scribn. brome grass G9 Calamagrostis lapponica (Wahlenb.) Hartm. reed-bent grass GS Carex atrata L. sedge G51 Carex limosa L. sedge G50 Carex pennsylvanica Lam. sedge Ggb20 Deschampsia caespitosa (L.) Beauv. tufted hairgrass GI Elymus innovatus Beal hairy wild-rye G5 Festuca ovina L. sheep fescue G4 Festuca scabrella Torr. rough fescue G6 Hierochloe alpina (Sw.) Roem and Schult. alpine holy grass Gil Kobresia myosuroides (Vill.)Fiori S Paol. kobresia G15 Phleum commutatum Gandoyer mountain timothy G54 Poa alpina L. alpine bluegrass G3 Poa arctica R.Br. arctic bluegrass Ggb25 Poa fendleriana (Steud.)Vasey Fendler's bluegrass G10 Poa leptocoma trin. loose-flowered bluegrass Ggb24 Poa nevadensis Vasey Nevada bluegrass G3 Poa rupicola Nash. timberline bluegrass G55 Poa sp. bluegrass G2 Trisetum spicatum (L.) Richter spike trisetum 125 Forbs: F56 Achillea millefolium L. subsp. borealis Bong. yarrow F45 Aconitum delphinifolium DC. monkshood Fgb5 Agoseris glauca (Pursh) Rof. false dandelion F228 Anemone multifida Poir. cut-leaved anemone F6 Anemone narcissiflora L. anemone F15 Anemone parviflora Michx. prairie windflower F35 Antennaria monocephala DC. white pussytoe F59 Antennaria rosea Greene rosy pussytoe F36 Arnica alpina (L.) Olin alpine arnica F61 Arnica cordifolia Hook. heartleaf arnica F42 Artemisia norvegica Fries Norwegian sage Fgb208 Artemisia Tilesii Ledeb. Tile's sage Fgb204 Astragalus alpinus L. alpine milk vetch F50 Campanula lasiocarpa Cham. bellflower F43 Campanula uniflora L. alpine harebell Fgb205 Cardamine pratensis L. cuckoo flower F22 Castilleja miniata Dougl. common red-paintbrush F33 Cerastium L. sp. chickweed F51 Cerastium L. sp. chickweed F222 Cornus canadensis L. bunchberry Fgb3 Crepis elegans Hook. hawksbeard F225 Crepis nana Richards hawksbeard Cryptantha interrupta (Piper) Payson F71 Delphinium br achy centrum Ledeb. larkspur F211 Draba aurea Vahl golden whitlow grass F221 Draba lanceolata Royle draba F23 Draba oligosperma Hook. few-seeded draba 126 F217 Draba L. sp. draba Fll Dryas integrifolia M. Vahl white dryas Fgb7 Epilobium latifolium L. large flowered fireweed F49 Epilobium angustifolium L. common fireweed Fgb7 Erigeron acris L. f leabane F2 Erigeron grandflorus Rydb. fleabane F39 Erigeron hymilis Graham fleabane F63S64 Erigeron peregrinus (Pursh) Green mountain daisy subsp. callianthemus (Green ) Cronf. Fgb206 Equisetum arvense L. common horsetail F71(M) Equisetum scirpoides Mich. dwarf horsetail F4 Fragaria virginiana Duchesne wild strawberry F54 Galium boreale L. northern bedstraw F38 Gentiana glauca Pall. gentian F69 Gentiana propinqua Richards. four-parted gentian F5 Gentiana prostrata Haenke white-margined gentian Fgb6 Geum aleppicum Jaeq . avens F5 Hedysarum alpinum L. lcments subs, americanum (Michx.) Fedtsch F21 Lathyrus ochroleucus Hook. yellow-flowered peavine Linnaea borealis L. twin-flower F16 Lupinus arcticus S. Wats. arctic lupine F75 Luzula parviflora (Ehrh.) Desv. wood rush F47 Luzula spicata (L.) DC spike wood rush F67 Melandrium affine J. Vahl 4 o'clock F44 Mertensia paniculata (Ait.) G. Don tall mertensia F29 Myosotis alpestris F.W. Schmidt alpine forget-me-not Fgb2 Oxyria digyna (L.) Hill mountain sorrel 127 F227 Oxytropis deflexa (Pall.) DC. deflexed locoweed F18 Oxytropis nigrescens (Pall.) Fisch. dark hair locoweed F8 Oxytropis sericea Nutt. early yellow locoweed F100 Oxytropis splendens Dougl. showy locoweed F99 Parnassia palustris L. bog star Fgb207 Pedicularis Kanei E. Durand hairy lousewort F223 Pedicularis labradorica Wirsing Labrador lousewort Fl Pedicularis oederi M. Vahl lousewort F25 Pedicularis sudetica Willd. lousewort F20 Penstemon procerus Dougl. scorched penstemon FIO Polemonium actutiflorum Willd. Jacobs ladder F27 Polemonium pulcherrimum Hook. Jacobs ladder F41 Polygonum vivparum L. alpine bistort F26 Potentilla diversifolia Lehm. mountain meadow cinquefoil F7a Potentilla hookeriana Lehm. cinquefoil F7b Potentilla hyparctica Malte cinquefoil F3 Potentilla nivea L. cinquefoil F226 Potentilla pennsylvanica L. Pennsylvanian cinquefoil F7c Potentilla villosa Pall. wolly cinquefoil F202 Pyrola asarifolia Michx. common pink wintergreen F55 Pyrola minor L. lesser wintergreen F37 Pyrola secunda L. one-sided wintergreen Fgb220 Ranunculus hyperboreus Rottb. buttercup F216 Ranunculus nivalis L. snow buttercup F66 Rhinanthus minor L. yellow rattle F40 Rumex acetosa L. garden sorrel F31 Saxifraga caespitosa L. tufted saxifrage 128 F>48 Saxifraga cernua L. tufted saxifrage F24 Saxifraga flagellaris Willd. spiderplant F34 Saxifraga nivalis L. snow saxifrage F30 Saxifraga oppositifolia L. purple mountain saxifrage F229 Saxifraga punctata L. cordate-leaved saxifrage F9 Saxifraga tricuspidata Rottb. prickly saxifrage F53 Sedum lanceolatum Torr. stonecrop FM-6 Senecio lugens Richards. ragwort Fgbl Senecio pauciflorus Pursch ragwort Sibbaldia procumbens L. sibbaldia F60S65 Silene acaulis L. moss campion F260 Silene parryi (Wats.) Hitchc. S Maguire Parry's campion F52 Silene repens Patrin creeping campion F22L| Smilacina stellata (L.) Desf. star-flowered solomons-seal F19 Solidago multradiata Ait. goldenrod F70 Stellaria longipes Goldie long-stalked chickweed F 3 2 Taraxacum alaskanum Rydb. Alaska dandelion Fgb4 Thlaspi arvense L. pennycress Thalictrum occidentale Gray western meadow rue F62 Veronica wormskjoldii Roem £ Schult. speedwell ViGia americana Muhl. American vetch F57 Zygadenus elegans Pursh white camas Shrubs and half-shrubs: Alnus incana (L.) Moench alder S54 Amelanchier alnifolia (Nutt.) Nutt. Saskatoon S23(M) Arctostaphylos rubra (Rehd. S Wilson) Fern. alpine bearberry S5 Arctostaphylos uva-ursi (L.) Spreng. bearberry 129 S17 Betula glandulosa Michx. glandular birch Cl Cassiope tetragona (L.) D. Don white mountain heather S26 Finpetrum nigrum L. crowberry Juniperus communis L. common juniper S54 Ledum groenlandicum Oeder Labrador tea Lonicera involucrata (Richards.) Banks black twinberry S10 Potentilla fruticosa L. shrubby cinquefoil S3 Rhododendron lapponicum (L.) Wahlenb. Lapland rosebay S53 Ribes oxyaconthoides L. wild gooseberry S12 Rosa acicularis Lindl. prickly, rose Fgb218 Rubus arcticus L. trailing raspberry F72(N) Rubus chamaemorus L. cloudberry F219 Rubus idaeus L. raspberry S50 Salix alaxensis (Anderss.) Cov. Alaska willow S20 Salix barclayi Anderss. Barclay's willow S13 Salix glauca L. glaucous willow S23(N) Salix lanata L. hairy willow S51 Salix myrtillifolia Anders. willow S6 Salix polaris Wahlenb. dwarf willow Sl Salix reticulata L. netted willow S21(b) Salix scouleriana Barratt Scouler's willow S21(d) Salix subcoerulea Piper silvery-green willow Shepherdia canadensis (L.) Nutt. Soapalallie S8 Vaccinium uliginosum L. alpine blueberry S9 Vaccinium vitis-idaea L. lingonberry Viburnum edule (Michx.) Raf. high-bush cranberry Trees: Abies lasiocarpa (Hook.) Nutt. alpine fir Betula papyrifera Marsh paper birch Picea glauca (Moench) Voss white spruce Picea mariana (Mill.)Britt., Sterns S Pogg black spruce Pinus contorta Dougl. ex Loud. lodgepole pine subsp. latifolia (Engelm) Critchfield Populus balsamifera L. balsam poplar Populus tremuloides Michx. trembling aspen Ferns: Cystopteris tragilis (L.) Bermh. fragile fern Dryopteris fragrans (L.) Schott. fragrant shield-fern F201 Lycopodium complanatum L. ground cedar References Hitchcock, C.L. et al. 1959. Vascular Plants of the Pacific Northwest. University of Washington Press, Seattle. In five parts Hubbard, W.A. 1969. The Grasses- of British Columbia. British Columbia Provincial Museum handbook No.9. Hulten, E. 1968. Flora of Alaska and neighbouring territories Stanford University Press, Stanford, California. Moss, E.H. 1959. Flora of Alberta. University of Toronto Press. Schofield, W.B. 1969. Some common mosses of British Columbia. British Columbia Provincial Museum handbook No. 28. APPENDIX 2 Scientific and common names and authorities for mammals and birds mentioned in'the text. References include: Cowan and Guiget (1965) and Godfrey, W.E. (1966). 133 Mammals: Alces alces andersoni Peterson Moose Canis latrans Say Coyote Can is lupus Linnaeus Wolf Castor canadensis Kuhl American Beaver Cervus canadensis nelsoni Bailey Rocky Mountain Elk Eutamias minimus (Bachman) Least chipmunk Gulo luscus luscus (Linnaeus) Wolverine Lynx canadensis canadensis Kerr Canada Lynx Marmota caligata (Eschscholtz) Hoary Marmot Neotoma cinerea (Ord) Pack Rat Odocoileus hemionus hemionus (Rafinesque) Mule Deer Oreamnos americanus (Blainville) Mountain Goat Ovis canadensis canadensis Shaw Rocky Mountain Bighorn Sheep Ovis canadensis californiana Douglas California Bighorn Sheep Ovis dalli dalli Nelson Dall Sheep Ovis dalli stonei Allen Stone Sheep Rangifer tarandus osborni Allen Osborn Caribou Ursus americanus Pallas Black Bear Ursus arctos horribilis Ord. Grizzly Bear Birds: Aquila chrysaetus (Linnaeus) Golden Eagle' Haliaeetus leucocephalus (Linnaeus) Bald Eagle APPENDIX 3 Some typical soil profiles and additional soils data from the Nevis Creek study area. 135 Profile description of a Mini Humo-Ferric Podzol developed under the Picea-Abies forest at site #17. Horizon Depth (cm) Description L-F 5-0 Needles, mosses and woody fragments. Ae 0-5 Light gray (10YR 7/Id)* loam; fine granular, friable; extremely acid; abrupt boundary Bf 5-15 Yellowish brown (10YR 5/4d) loam; weak, medium subangular blocky; firm; extremely acid; clear boundary BC 15-30 Grayish brown (10YR 5/2 d) loam; moderate, medium subangular blocky; firm gradual boundary Ck 30-62 Dark grayish brown (10YR 4/2 d) loam; strong, angular blocky; very firm, mildly alkaline. Munsel notation 136 Profile description of a Black Chernozem (Alpine Eutric Brunisol) developed under small, scattered Populus spp. and dense Elymus innovatus, Horizon Depth (cms) Description Ah 0-20 Black (10YR 2/1 d) sandy loam; moderate, fine granular; friable; slightly acid; clear boundary Bm 20-25 Dark brown (7.5 YR 3/2 m) gravelly sandy loam; weak, medium subangular blocky; friable; slightly acid; gradual boundary BC 25-46 Dark grayish brown (10 YR 4/2d), cobbly gravelly sandy loam; weak, medium subangular blocky, very friable, neutral; gradual boundary BCk 46-68 Dark grayish brown (10YR 4/2d) cobbly gravelly sandy loam; weak subangular blocky; very friable; mildly alkaline; abrupt boundary R 68+ Limestone 137 Profile description of a Eutric Brunisol under an Elymus-Festuca plant community at site ID Horizon Depth (cm) Description Ahe 0-5 Very dark grayish brown (10YR 3/2 m) loam; moderate fine granular; friable; medium acid; clear boundary Bml 5-18 Dark brown (10YR 3/2 m) loam; weak, moderate subangular blocky; friable; medium acid; gradual boundary Bm2 18-46 Dark yellowish brown (10YR 4/4m) loam; weak; moderate subangular blocky; friable; slightly acid; diffuse boundary BC 46-91 Very dark grayish brown (10YR 3/2m) loam; weak, fine subangular blocky; friable; neutral 138 Profile description of a Lithic Dystric Brunisol under the Silene- Calamagrostis plant community at site 4A Horizon Depth (cm) Description Ah 0-5 Very dark brown (10YR 2/2d) loam; moderate, medium granular; friable; extremely acid; clear boundary Bm 5-15 Brown (10YR ^/3d) sandy loam; weak, medium subangular blocky; extremely acid; gradual boundary Cl 15-20 Brown to yellowish brown (10YR 5/3.5d) sandy loam; weak; subangular blocky; extremely acid; abrupt boundary R 20+ Yellowish brown sandstone 139 Some additional chemical and physical properties of forest and valley soils at Nevis Creek —— Available Fine Base Exchangeable Oxalate/extractable Sand Silt Clay Clay Site Horizon Satn. Cations (mg /100g) *P(ppm) Fe(%) Al(%) (%) (%) (%) (%) Mg Na 16 Ah 63.80 5.54 0.02 79.1 0.65 0.11 ACg 0.52 1.57 0.01 178.2 1.16 0.08 Cl 100+ 1.98 0.01 477.1 0.76 0.10 C2 100+ 1.63 0.01 216.9 0.46 0.06 16 Ae 8.17 0.13 0.01 20.6 0.06 0.06 44.6 49.1 6.3 2.1 Bf 100+ 0.80 0.01 427.2 1.00 0.22 39.9 41.1 19.0 9.1 BCk 100+ 0.71 0.04 8.2 0.40 0.04 55.7 31.6 12.7 5.1 12 Ae 14.4 0.15 0.08 Bm 123.7 0.34 0.10 BC 64.2 0.04 0.05 17 H 17.7 Al Ah 97.52 2.56 0.03 120.6 48.9 32.6 18.5 Bm 98.14 0.97 0.02 10.24 57.7 27.2 15.1 9.0 BC 100+ 0.37 0.03 487.5 17.4 63.9 18.7 8.9 A2 Ahe 4.31 0.03 68.4 * Available P by the Bray #3 method 140 Some additional chemical and physical properties of alpine soils at Nevis Creek Exchangeable Available Oxalate Fine Base Cations (meg/100) *P extract Sand Silt Clay Clay Site Horizon Satn. Mg Na (ppm) Fe(%) Al(%) (%) (%) (%) (%) 10B Ah 115.6 46.6 39.5 16.9 8.7 BC 170.5 45.1 30.7 24.2 13.1 10A Ah 96.78 3.31 0.02 101.7 36.6 41.5 21.9 11.8 CBk 100+ 0.33 0.02 55.6 44.2 41.6 14.2 7.8 3A H 100+ 6.87 0.08 48.3 24.1 49.0 26.9 14.1 ID Bm 39.4 0.50 0.19 46.1 36.7 17.2 7.2 Cl 477.7 0.26 0.10 44.6 39.6 15.8 10.3 2C Ahe 20.7 2B Ahe 10.2 0.12 0.08 Bm 14.0 0.36 0.13 BC 357.4 0.24 0.13 1C Ae 0.73 4.38 0.03 18.5 0.41 0.11 Bm 55.77 2.18 0.04 11.2 0.32. 0.13 BC 41.49 0.76 0.02 8.1 0.15 0.07 5A Ahe 21.5 0.60 0.35 Bm 14.8 0.47 0.22 4B Ahe 18.26 1.02 0.04 41.1 0.22 0.27 41.9 37.0 21.1 9.43 Bm 5.57 0.09 0.02 34.9 0.62 0.24 53.0 30.7 16.3 2.80 BC 4.37 0.02 0.02 104.0 0.89 0.24 60.8 23.9 15.3 8.20 * Available P by the Bray #2 method APPENDIX 4 Miscellaneous climatic data and a list of instruments used to measure climate in the Nevis Creek area. APPENDIX 4 Monthly and annual Mean Temperatures for the year 1970 Station Fort St. John Mean max. 4.1 27.9 33.6 47.7 58.2 69.8 70.8 70.1 58.0 49.2 19.5 8.2 43.0 Airport Mean min. -11.7 13.7 16.2 30.0 38.6 47.9 49.0 49.0 39.7 30.9 705 -6.1 25.4 Mean daily - 3.8 20.8 24.9 38.9 48.4 58.9 59.9 59.6 48.9 40.1 13.5 1.1 34.2 Fort Nelson Mean max. - 2.7 19.1 33.1 46.8 60.6 71.0 73.7 70.7 56.4 40.5 16.3 -1.6 40.2 Mean min. -19.2 1.6 10.4 25.9 38.0 48.6 49.1 48.4 36.3 23.8 2.0 -14.5 20.8 Mean daily -11.1 10.4 21.8 36.4 49.3 60.1 61.4 59.6 46.4 32.2 9.2 -8.1 30.6 Fort Nelson Mean max. 8.1 29.5 26.5 33.5 43.1 57.2 57.1 55.2 42.7 36.0 21.5 9.2 34.9 Churchill Mines Mean min. -3.2 15.4 12.2 19.0 29.0 38.6 39.9 38.6 36.0 23.2 7.4 -5.4 20.4 Mean daily 2.5 22.5 19.4 26.3 36.1 47.9 48.5 46.9 36.9 29.6 14.5 1.9 27.7 143 Description of Canada Land Inventory Equipment Rimco Sumner Mark II/RT Recorder: The Rimco Recorder has been adapted to the recording of temperature and rainfall in the Canada Land Inventory Network. The instruments are designed to record for a six month period without being checked. Therefore, Rimco instrumentation is most often placed in more remote localities. The range of the instrument for temperature recordings is from -60°F to 130°F. Rain• fall measurement up to 400 mm/hr (15 inches/hr) can be handled. A tilting bucket raingauge (diameter 5 inches) is placed in a level, unobstructed position, fairly close to the power source. The rate and amount of rainfall may both be determined by using this instrument. Lambrecht Thermograph: The Lambrecht Thermograph is primarily used throughout the climatolo• gical networks in the interior. The range of the instrument's use is from -30°F to +130°F. The accuracy of the thermograph is within plus or minus 1.5% of the total range of measurement. The temperature recorded is a function of bimetallic strips contraction and expansion. The temperature trace is recorded on a monthly chart. Each month the calibration of the thermograph is checked against a zeal minimum. The lowest temperature on the thermograph is compared to the monthly ininimum registered on the mirLimum thermometer. The difference between the thermograph's value and the mirumum thermometer results in a correction factor which is then applied to the month's information. Kahlsico Thermograph: The Kahlsico Thermograph is in use throughout most of the remainder of the interior. The range of the iristrument is indicated at from -40°F to +120°F. 144 The accuracy is similar to that of the Lambrecht thermograph. The temperature trace is recorded on a monthly chart, and the correction factor is calculated in the same fashion as for the Lambrecht thermograph. Fuess Hygrothermograph: The Fuess Hygrothermograph records both relative humidity and temperature in degrees Fahrenheit. The range of temperature the instrument is capable of recording is from -40°F to +110°F. The monthly correction factor is calculated in the same manner as the Lambrecht and Kahlsico thermographs. The instrument is:>.'reasonably accurate from 0 to 100% for humidity measurement. The degree of accuracy is from plus or minus 5% for all hygrothermographs in use. Temperatures and humidities are recorded on a seven day chart. Zeal Minimum Thermometers: Zeal Minimum Thermometers are placed at each temperature station in order to determine the correction factor of temperature data. Minimum temperatures are also used to determine whether the thermograph requires re-calibration. The range of the thermometers is from -90°F to +110°F. Brannan Maximum Thermometers: Brannan Maximum Thermometers are similarly used to check the upper range of calibration of the thermographs. Secondly, if the minimum temperature values are unobtainable for some reason, the maximum thermometer indicates to r some degree the accuracy of the calibration. The range of thermometers is from -35°F to +120°F. Rain Gauges: a) Rain Gauge (long storage plastic material or metal type) These rain gauges are twenty-four inches in height and have a 6.115 inch in diameter opening. The storage capacity is twenty inches and as a result the gauges are placed in areas of heavy rainfall or locations which are not visited often (six month Rimco stations for example). 145 b) Rain Gauge (short type) These rain gauges are placed in the majority of locations. The gauges are twenlve inches in height, and are coated with a protective layer of aluminum paint. The gauge opening is fitted with a funnel having a 3/8 inch diameter hole in the funnel's centre. A substantial amount of kerosene is poured into each gauge to prevent evaporation of the rain which falls. a + b) Rain Gauges (both types) The rain gauges are positioned at temperature and precipitation stations throughout network areas. The gauges are installed on level ground and free from any obstruction. This practice insures that total rainfall catch represents fairly closely the rainfall falling in an area. At each station, two rain gauges are established so as to minimize error and to better insure some reading will be obtained. Rain gauges are kept at the Climatological stations during the April - May to September - October period only. Stevenson Screen The Stevenson Screen is a large louvered box very similar to the type used by the Atmospheric Environmental Service. The screen houses a thermograph or hygrothermograph, and maximum and miramum thermometers. The screen is positioned so that the thermograph's sensor is positioned four feet above the ground and the screen door is oriented to the north. 146 APPENDIX 5 A comparison of some water and acid soluble elements in a mineral lick soil and an unrelated sample from the alpine slopes. Major elements (lbs/acres) Related soil properties Na P K Ca CEC Ca/mg ratio Lick sample 7 8.9 4 173 9550 27.9 6.3 Control sample 37.2 180 14125 40.2 7.7 "iMinor elements (p.p.m.) Mn Zn Cu Pb Ni Co Lick sample 130.5 76.9 26.9 4.8 55.0 10.0 Control 120.9 72.7 15.5 12.0 26.9 7.8 Sample "Acid soluble extracts. Concentrations determined by total digestion using HF and HC10L. Selenium tested for toxicity levels only. Table 14b: Shrub measurements for four sites in the 'Elymus-Festuca community Species SITE LA IB IC ID 1% D Ht. Cr. 1% D Ht. Cr. 1% D Ht. Cr. 1% D Ht. Cr. x" D x" D x" • D x" D 5?» x" x" x" Potentilla fruticosa 85 0.6 9.6 9.7 0 0 85 0.9 11 9 90 1.6 7.6 3.6 Salix glauca 20 0.3 10.6 12.6 70 0.6 12.4 18 15 0.1 12 20.5 10 tr 26 39 Betula glandulosa 0 0 50 0.3 12 24 0 0 0 0 Rosa acicularis 0 0 10 0.1 10 8 0 0 0 0 Ht = Average Height in inches.Cr. D. Average crown diwmeter in inches Tr = trace Table 14c: Soil surface components for four sites in the Elymus-Festuca ccmmunity Soil Surface SITE components 1A % IB % IC % TD % " bare soil 8 8 7 0 rock 8 4 10 10 litter 42 47 47 40 Cryptogams (living) (mosses, lichens) 7 5 6 7 Phanerogams (living) (higher plants) 36 36 30 43 NEVIS CREEK STUDY AREA 123° 30' I23°I7'30" 57 ° 27 30 57°27'30' L 57° 25 57 °25 -\ 57° 20' 57°20 123 ° 30' SCALE 131,680 1/2 0 2 MILES H KH ( part of 94G/GW VEGETATION COMMUNITIES SYMBOL GRASSLAND SYMBOL FOREST SYMBOL STREAMSIDE Elymus-Festuca Picea-Abies B' Salix-Epilobium (Gravel Bar) • F| • b • lbJ Elymus - Agropyron oJ North Slope Picea T Salix-Betula (Terrace) F Pinus - Salix • Dryas-Festuca 2 • OTHERS c3 Silene- Calamagrostis Betula- Pinus • ^3 • N • Cryptogram- Salix G Calamagrostis-Hierochloe (E-slope) F4 Betula- Abies 4 • • R n Rock or Unvegetated Erosion Slope • Festuca-Dryas A P Populus Valley Meadow • SHRUB Betula-Vaccinium uliginosum Study site locations SIE Betula -Vaccinium vitis-idaea S2 Betula- Salix