Mountain Caribou Habitat Use in the Salmon Arm
Forest District:
2000-2002
Preliminary Report #1
Kelsey Furk1
Bruce McLellan2
March 2003
1
2
PO Box 215, Heffley Creek, BC. (250) 578-0423, kfurk@hotmail.com
Ministry of Forests, Research Branch. Columbia Forest District, (250) 837-7767
Table of Contents
1.0
Acknowledgements ....................................................................................... 4
2.0
Introduction.................................................................................................... 4
3.0
Study Area...................................................................................................... 6
4.0
Methods .......................................................................................................... 6
5.0
Results ........................................................................................................... 8
5.1
Progress of telemetry monitoring ................................................................. 8
5.2
Habitat Utilization ....................................................................................... 10
5.2.1
Seasonal elevation shifts by caribou ................................................... 12
5.2.2
Aspect use by caribou......................................................................... 12
5.2.3
Slope use by caribou .......................................................................... 13
5.2.4
Land Cover use by Caribou ................................................................ 15
5.2.5
Forest cover characteristics used by caribou ...................................... 16
5.3
Distribution of Caribou and Seasonal Range ............................................. 19
6.0
Discussion ................................................................................................... 23
6.1
Habitat Utilization ....................................................................................... 23
6.2
Distribution and home range ...................................................................... 24
7.0
References ................................................................................................... 25
Table of Figures
Figure 1. Okanagan Shuswap Land and Resource Management Plan designated
Mountain caribou resource management zone. ........................................................ 5
Figure 2. Historic and recent caribou locations in and surrounding the study area. ... 9
Figure 3. The inter-annual MCP home range of all caribou with locations in the
Salmon Arm forest district. This area defines what was considered 'available' to
caribou for the habitat analysis. ................................................................................. 11
Figure 4. Monthly average elevation for female caribou that had at least one location
in the study area. Error bars represent +/- 1 standard deviation. ......................... 12
Figure 5. Aspects used by caribou for all seasons based on VHF data only. ............ 13
Figure 6. Aspects used by caribou over all seasons based on GPS data only. ....... 13
Figure 7. Slopes used by caribou in each season based on VHF re-locations only. 14
Figure 8. Slope categories used by caribou as a percentage of all re-locations
recorded in each season.3 .......................................................................................... 14
Figure 9. The cumulative percent of locations recorded during early winter. ............. 15
Figure 10. The cumulative percent of locations recorded during late winter. ............. 15
Figure 11. Stands used by caribou in during each season based on VHF relocations. (B- balsam, CW-cedar, FD-Douglas fir, H-hemlock, S-spruce). ........ 16
Figure 12. Leading species of stands used by caribou based on GPS locations. ..... 17
Figure 13. Age Class of stands used by caribou during each season based on VHF
data. ............................................................................................................................... 17
Figure 14. Age class of stands used by caribou during each season based on GPS
data................................................................................................................................. 18
Figure 15. Crown closure of stands used by caribou based on VHF locations. ....... 18
2
Figure 16. Crown closure class of stands used by caribou based on GPS data. ...... 19
Figure 17. Kernel Home Range (90%) of caribou in herds delineated using
telemetry data (Heiko Wittmer, UBC, unpubl. data). .............................................. 20
Figure 18. Caribou locations by season for caribou monitored since 2000 in the
Seymour River area. .................................................................................................... 21
Figure 19. Locations for caribou in the Boulder Mtn. - Queest Mtn. area and the
Blanket Glacier area. Each polygon represents the inter-annual home range of
an individual animal. .................................................................................................... 22
List of Tables
Table 1. Habitats used by caribou, by season, recorded by an observer during
telemetry flights. ........................................................................................................... 16
3
1.0
Acknowledgements
The Okanagan Innovative Forestry Society (OIFS) contracted this study.
Funding was provided through the Ministry of Forests “Forest Investment Account”.
Bruce McLellan, Ministry of Forests Research (Revelstoke) provided input and
manages the telemetry study. Fernando Cocciolo, of LP Engineered Wood Products
Ltd. and Carole Dascher of Pioneer Forest Consulting Ltd. planned and
administered project activities. Garry Darychuk of the Ministry of Forests Nelson
Forest Region assisted in the planning phase of this project. Special thanks to Dave
Mair of Silvertip Aviation for his excellent piloting. Animal capture was conducted by
Bighorn Helicopters. Thanks also to John Surgenor (WLAP Kamloops) for input and
logistic support.
2.0 Introduction
Mountain caribou are an ecotype of woodland caribou (Rangifer tarandus
caribou) that, except for a small population in Idaho, are found exclusively in southeastern and east-central British Columbia.
Mountain caribou have specific seasonal habitat requirements. During early
winter caribou use lower elevation, older closed canopy forests that provide snow
interception and access to forage that includes shrubs, arboreal lichen and lichen
litterfall. During late winter, caribou move to higher elevation ESSF and sub-alpine
forests where they feed primarily on arboreal lichens (Simpson et al. 1997,
Stevenson et al. 2001). During spring, some caribou remain at high elevations but
many move to low elevations where they access snow-free foraging areas. Female
caribou move to the alpine to avoid predators while giving birth. Connectivity
between seasonal ranges is required to facilitate movement. In addition to
requirements for forage and cover, caribou distribute themselves over large areas to
reduce efficiency of predators. Habitat alteration that results in increased predator
numbers and access to caribou may contribute to population decline.
In 2000 mountain caribou were moved from the blue list to red list in British
Columbia indicating that populations within the province are at risk of becoming
endangered. In May 2002 the Committee on the Status of Endangered Wildlife in
Canada (COSEWIC) confirmed that the southern mountain population of caribou
was threatened. The following statement summarizes reasoning for the designation:
“Local herds in the Southern Mountains population are generally small,
increasingly isolated, and subject to multiple developments. Their range has shrunk
by up to 40% and 13 of 19 herds are declining. The most southerly herds are likely
to disappear. Many herds are threatened by decreasing habitat quantity and quality,
harassment and predation.” (COSEWIC website, January 2003).
The Okanagan Shuswap Land and Resource Management (OSLRMP) area
contains part of three caribou populations identified by Simpson et. al (1997). These
are the Wells Gray South, Revelstoke and Monashee populations. In 2001
(OSLRMP) established a Caribou Resource Management Zone (RMZ) with
4
associated connectivity corridors in the Okanagan TSA (Figure 11). The OSLRMP
specifies management guidelines for Caribou in this RMZ.
Figure 11. Okanagan Shuswap Land and Resource Management Plan designated
Mountain caribou resource management zone.
5
The Okanagan Innovative Forestry Society (OIFS) contracted a caribou study in
response to the OSLRMP call for further caribou habitat information. This report
documents progress of the study over the first two years of a seven-year project.
The OIFS Forestry Plan (2001) identifies five main objectives for this project:
1. Identifying the caribou habitat requirements in the ICH and ESSF zones;
2. Examining the relationship between forest management activities and relative
caribou habitat use in the ICH and ESSF zones.
3. Identifying opportunities to supply suitable caribou habitat attributes through
forest management activities.
4. Investigating caribou populations, including predation and mortality; and
5. Link monitoring from this project to ongoing caribou research projects in the
Columbia and Clearwater Forest Districts.
Caribou research projects in the Columbia and Clearwater Forest districts have
also identified caribou movements in the Salmon Arm Forest District. Data from all
three studies will be combined to complete the objectives of this study.
3.0 Study Area
The approximate study area is located in the Monashee Mountains
surrounding the Shuswap Lake area. Major watersheds in the area include the
Seymour River and the Eagle River watersheds. The study area falls in the
Northern Columbia Mountains ecoregion. Biogeoclimatic zones in the study area
include the Interior Cedar Hemlock Zone, the Engelmann Spruce – Subalpine Fir
zone and the Alpine Tundra Zone.
4.0 Methods
Based on local knowledge, information from caribou studies in adjacent Forest
Districts, and historical evidence, areas where caribou had been recently sighted
were searched using a helicopter in late winter. During this period they use subalpine forests and their tracks can be easily seen. Areas searched include the Perry,
Anstey and Seymour River Drainages, and the North Queest Mountain, Pukeashun
Mountain and Blanket Glacier areas. When caribou were discovered, a sample of
individuals was captured using a net gun fired from a helicopter and handled by a
crew that specialises in animal capture (Bighorn Helicopters) and MOF personel.
Ministry of Water, Land and Air Protection live animal capture and handling
guidelines were followed in these operations. Caribou were outfitted with
conventional Very High Frequency (VHF) radio-collars (Lotek Wireless) or Global
Positioning Collars (GPS) (Advanced Telemetry Systems) that recorded and stored
the location of the animal every six hours.
A monitoring program using fixed wing aircraft with radio tracking equipment
recorded the location of all collared animals on a regular schedule using an on-board
GPS system. Flights were weather dependent, but were generally completed once a
week in early winter and once every two weeks during the rest of the year.
Telemetry flights were conducted in conjunction with monitoring in the Clearwater
6
and Columbia Forest Districts. Each VHF location was checked in a Geographic
Information System (GIS) to ensure locations were correct prior to being entered into
the database. During flights a visual confirmation of animal location was attempted
and if seen, the number of caribou including calves (when possible to distinguish) in
the group were recorded. For all re-locations, the habitat type of the caribou location
was recorded as well as the general location (in order to identify errors in the data).
The location habitat types are as follows:
1.
2.
3.
4.
5.
6.
7.
Alpine
sub-alpine parkland
meadow
ESSF
clearcuts (<20 years old)
burns (<30 years old)
cedar-hemlock
8. slide-path
9. immature forest (class 2-3)
10. riparian wetland
11. cedar-spruce
12. rock, ice, lake
13. semi-mature forest (class 4-5)
14. riparian parkland
All radio-collars contained motion sensors that transmit a different signal
when the caribou died (or a collar falls off). Each death was investigated as soon as
possible upon discovery. The location, condition and position of the carcass as well
as any predator sign were used to determine the cause of death.
In collaboration with efforts in the Clearwater and Columbia Forest Districts,
helicopter census flights were flown in 2002 and will continue to be flown annually if
snow conditions are suitable to count caribou. The presence of radio-collared
caribou in the population allows for a more accurate population estimate using a
mark re-sight calculation.
The locations of all caribou in this and adjacent study areas were mapped to
help define the current distribution of caribou in the study area and relationships to
caribou in adjoining Forest Districts. The habitat type recorded during telemetry
flights is presented in addition to the forest cover characteristic analysis. These
habitat units are not directly comparable to any mapping resources that could be
used to derive the amount of habitat available to be used for a statistical “use vs.
availability analysis. However, these data present accurate information regarding
habitat use that is not subject to the compounding and difficult to measure error
involved in recording locations with a GPS and merging them with mapped land
characteristics to determine habitat type.
In addition to these data, and in order to compare habitat use with available
mapping resources that could approximate the available habitat in the area, a
Geographic Information System (GIS) by ESRI was used to apply forest and terrain
attributes to each caribou location. Locations from individuals were pooled, and
results are presented separately for each season. VHF and GPS data was also
presented separately due to concerns regarding bias in GPS data caused by
differences in successful fix rates in different habitats. Most of the GPS data was not
differentially corrected. All 3 dimensional and 2 dimensional GPS locations with a
dilution of precision greater than or equal to 20 were omitted from the habitat use
analysis and location maps.
The area defining what habitat was considered ‘available’ to caribou was the
collective inter-annual home range of caribou in the study area. The minimum
7
convex polygon (MCP) home range was calculated for all locations for each caribou
individually (from this study and studies in adjoining Forest Districts, that had
locations in the Salmon Arm Forest District). All of the MCP home ranges were then
merged together. Slope, aspect, elevation and forest cover were clipped to this area
and the relative contribution (as a percent of the total area) of each category was
calculated.
The slope for each relocation fell into one of 8 categories: 0-10%; 11-20%;
21-30%; 31-40%; 41-50%; 51-60%; 61-70% and greater than 70%. The aspect
coverage contained five categories: nil, West, East, North, South. The elevation
coverage used for analysis was based on 100 m categories. To identify elevation
changes that mark seasonal movements, locations were viewed by day and for
females only, by monthly average elevation. All data from caribou with locations in
the Salmon Arm Forest district from this study as well as the Columbia and
Clearwater Forest District caribou studies were included in the analysis of aspect,
slope and elevation. These locations were recorded between March 1992 and
December 2002. Only recent (since 2000) locations were used in the analysis of
forest characteristics.
A number of steps were required to determine the land status at caribou relocations. Current layer one forest cover (projected to 1999, 2000 or 2001) was used
in the forest cover analysis. Locations with tree species data were included in the
forest cover characteristic analysis (including alpine and non-productive forest).
Sites with a non-forest descriptor of ‘not sufficiently restocked’ were also included in
the forest cover analysis of crown closure and age class (but not leading species)
since these areas are not currently forested but represent areas capable of
supporting commercial forests. To determine the land status of non-forested
locations, the non-productive forest descriptor and the non-forest descriptor were
consulted. Locations that fell in non-forested areas were not included in the forest
cover characteristic analysis. Forest cover characteristics analysed were stand age,
leading species and crown closure class.
5.0 Results
5.1
Progress of telemetry monitoring
The historic anecdotal sightings database and telemetry records from the
Clearwater and Columbia Forest Districts were used to identify historic areas of
Caribou use (Figure 22). These areas were searched and Caribou were collared in
the Seymour River area, the Queest Mountain area and one female was collared
south of the Trans-Canada highway near Blanket Glacier.
8
Figure 22. Historic and recent caribou locations in and surrounding the study area.
A total of 14 caribou (2 males, 12 females) have been monitored for the
project, three of these were collared prior to the start of the project in 2001. Eleven
caribou are currently being monitored and 3 of the monitored caribou have died
9
since the beginning of 2001. A total of 14 collars were deployed since March of
2001. Three caribou were recaptured in March 2002 to remove GPS collars
(removal is required to retrieve data) and be fitted with a new GPS or VHF collar.
Since the beginning of 2001, 276 VHF re-locations (from 7 VHF and 6 GPS collars)
and 4076 GPS locations (from 6 GPS collars) have been recorded. Of the GPS
locations 3949 had a dilution of precision of less than 20 and were included in the
analysis and presentation of data.
Mortality data were summarized in a separate report. Mortalities have been
recorded in the Cayenne Creek headwaters area during late winter and spring. Two
were of unknown cause, one was a wolverine predation and one was a wolf
predation.
5.2
Habitat Utilization
The cumulative minimum convex polygon home range for all caribou from the
Salmon Arm, Clearwater and Columbia telemetry projects with locations in the
Salmon Arm forest district is shown in Figure 33. This area represents what was
considered available to caribou for the purpose of the habitat analysis.
10
Figure 33. The inter-annual MCP home range of all caribou with locations in the
Salmon Arm forest district. This area defines what was considered 'available' to
caribou for the habitat analysis.
11
5.2.1
Seasonal elevation shifts by caribou
Dates of seasonal elevation shifts were similar to those determined from the
telemetry study in the Clearwater Forest District (Norquay 1999). The following
range of dates was used to identify seasons: late winter being January 16 th-March
31st, spring being April 1st-May 23rd, calving being May 24th-June 15th, summer being
June 16th-October 22nd, early winter being October 23rd-January 15th. Figure 44
illustrates seasonal shifts in elevation by female caribou. Caribou used the broadest
range of elevations in April and collectively occupied a narrow range of elevation
during late winter. Caribou used the ICH during spring and early winter. During late
winter, calving season, and summer, caribou were located primarily in the ESSF or
above.
2200
Female Locations - Average Elevation
AT
Elevation (m)
2000
1800
ESSF
1600
1400
1200
ICH
1000
VHF
800
GPS
Jan Feb Mar Apr May Jun Jul
Month
Aug Sep Oct
Nov Dec
Figure 44. Monthly average elevation for female caribou that had at least one
location in the study area. Error bars represent +/- 1 standard deviation.
5.2.2
Aspect use by caribou
The aspects used by caribou as a percent of the total re-locations for each
season are shown in Figure 55 and Figure 66. Caribou do not appear to have
selected for habitat based on aspect. There were relatively more locations on
southerly aspects recorded by GPS collars. South aspects are generally considered
better for recording GPS fixes.
12
N
W
N*
W*
V HF - A s p e c t
Pe r ce nt of Re locations
60%
E
S
E*
S*
50%
40%
30%
20%
10%
0%
CA
EW
LW
SP
SU
Se as o n
Figure 55. Aspects used by caribou for all seasons based on VHF data only.3
GPS - Aspect
N
W
N*
W*
Percent of Relocations
60%
50%
E
S
E*
S*
40%
30%
20%
10%
0%
CA
EW
LW
SP
SU
Season
Figure 66. Aspects used by caribou over all seasons based on GPS data only.
5.2.3
3
Slope use by caribou
The slopes used by caribou as a percent of the total re-locations in each
season are shown in Figure 77 and Figure 88. Most locations were on subdued
terrain (0-40% slope) in all seasons. Caribou were often located in steep (>80%)
terrain during calving season and were less often located on slopes over 40% during
late winter. During early winter, approximately 90% of locations were recorded on
slopes less than 60% (Figure 99). During late winter, approximately 90% of VHF
locations were recorded on slopes less than 50% (Figure 1010).
3
*Lines indicate relative availability of habitat type.
13
50%
VHF - Slope
45%
Percent of Relocations
40%
35%
30%
25%
20%
15%
10%
5%
0%
EW
LW
SP
Season
CA
SU
0-20%
21-40%
41-60%
61-80%
>80%
0-20%*
21-40%*
41-60%*
61-80%*
>80%*
Figure 77. Slopes used by caribou in each season based on VHF re-locations only.4
50%
GPS - Slope
45%
Percent of Relocations
40%
35%
30%
25%
20%
15%
10%
5%
0%
EW
LW
Season
SP
CA
SU
0-20%
21-40%
41-60%
61-80%
>80%
0-20%*
21-40%*
41-60%*
61-80%*
>80%*
Figure 88. Slope categories used by caribou as a percentage of all re-locations
recorded in each season.4
4
* lines indicate relative availability of each habitat type.
14
early winter slope use
cumulative percent
100%
80%
60%
Available
VHF
GPS
40%
20%
140
130
120
110
100
90
80
70
60
50
40
30
20
10
0
0%
percent slope
Figure 99. The cumulative percent of locations recorded during early winter.
late winter slope use
cumulative percent
100%
80%
60%
Available
VHF
GPS
40%
20%
140
130
120
110
100
90
80
70
60
50
40
30
20
10
0
0%
percent slope
Figure 1010. The cumulative percent of locations recorded during late winter.
5.2.4
Land Cover use by Caribou
Observers recorded the habitat types caribou were located in during VHF
telemetry flights (Table 11). Most caribou locations were in non-forested alpine
areas, sub-alpine parkland or in mature forest. There were relatively more locations
in clearcuts during spring and calving. Most early winter locations were in forested
areas. Caribou were primarily located in sub-alpine and alpine habitat in late winter.
15
Table 11. Habitats used by caribou, by season, recorded by an observer during
telemetry flights.
Season alpine
CA
3.0%
EW
0.5%
LW
14.0%
SP
0.8%
SU
12.2%
5.2.5
Habitat Type
subalpine riparian
riparian rock,ice,
parkland parkland slidepath meadow wetland
lake
43.3%
0.0%
3.0%
0.0%
0.0%
0.0%
12.0%
0.5%
0.0%
0.0%
1.0%
0.0%
60.4%
0.0%
0.0%
0.0%
0.0%
3.0%
28.7%
0.0%
3.1%
0.8%
4.7%
0.8%
25.5%
1.0%
3.1%
0.7%
3.1%
4.9%
ESSF
28.4%
35.9%
20.1%
23.3%
36.7%
Cw-Hw
10.4%
37.5%
1.2%
18.6%
8.4%
Cw- semiclearSp mature immature cut
burn
3.0%
1.5%
0.0% 7.5% 0.0%
6.8%
0.5%
0.0% 5.2% 0.0%
0.0%
0.0%
0.0% 1.2% 0.0%
7.8%
0.0%
0.8% 10.9% 0.0%
1.4%
0.0%
1.7% 0.7% 0.3%
Forest cover characteristics used by caribou
To avoid inaccuracies of using caribou locations recorded prior to recent
forest harvesting, only locations after 1999 were considered for the analysis of
forest cover characteristics. There were 300 VHF locations and 5063 GPS locations
(with a DOP of less than 20) that qualified. Of these 3673 GPS locations and 212
VHF locations were in forested areas and were used in the graphs of crown closure
and age class. Of these locations, two VHF and 29 GPS locations were in notsufficiently restocked stands that were excluded from the leading species graphs.
The majority of locations were recorded in balsam leading stands in all
seasons (Figure 1111 and Figure 1212). Caribou were primarily located in old
stands (age class 8 and 9) during all seasons, and were located in younger stands
more frequently during calving and spring (Figure 1313 and Figure 1414).
VHF - Leading Species
80%
percent of relocations
70%
60%
50%
40%
30%
20%
10%
0%
CA
EW
LW
SP
SU
Season
B
*B
CW
*CW
FD
*FD
H
*H
S
*S
Other
*other
Figure 1111. Stands used by caribou in during each season based on VHF relocations. (B- balsam, CW-cedar, FD-Douglas fir, H-hemlock, S-spruce). 5
5
*lines indicate relative availability of each habitat type.
16
GPS - Leading Species
90%
80%
percent of relocations
70%
60%
50%
40%
30%
20%
10%
0%
CA
B
*B
EW
LW
SP
Season
CW
*CW
FD
*FD
H
*H
SU
S
*S
Other
*other
Figure 1212. Leading species of stands used by caribou based on GPS locations.5
100%
VHF - Projected Age Class
Percent of re-l ocations in each season
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
CA
EW
LW
SP
SU
Season
0-1
*0-1
2-3
*2-3
4-5
*4-5
6-7
*6-7
8-9
*8-9
Figure 1313. Age Class of stands used by caribou during each season based on
VHF data. 5
17
Percent of re-locations in each season
100%
GPS - Projected Age Class
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
CA
EW
0-1
*0-1
LW
2-3
*2-3
SP
Season
4-5
*4-5
6-7
*6-7
SU
8-9
*8-9
Figure 1414. Age class of stands used by caribou during each season based on
GPS data.5
percent of locations in each
season
Caribou appear to prefer stands with mid range crown closures of 36-55%
during most seasons (Figure 1515 and Figure 1616). Caribou used stands with a
broader range of crown closures during spring and calving and used stands with
relatively higher crown closure during early winter.
70%
VHF - Crown Closure Class
60%
50%
40%
30%
20%
10%
0%
CA
EW
LW
SP
SU
Season
0-1
0-1
2-3
2-3
4-5
4-5
6-7
6-7
8-10
8-10
Figure 1515. Crown closure of stands used by caribou based on VHF locations. 5
18
percent of locations in each
season
60%
GPS - Crown Closure Class
50%
40%
30%
20%
10%
0%
CA
EW
0-1
0-1
2-3
2-3
LW
Season
4-5
4-5
SP
6-7
6-7
SU
8-10
8-10
Figure 1616. Crown closure class of stands used by caribou based on GPS data.5
5.3
Distribution of Caribou and Seasonal Range
The total minimum convex polygon home range of each caribou monitored since
2000 in the Seymour area is included in Figure 1818. The total minimum convex
polygon home range of each caribou monitored since 2000 in the Quesst Mountain/
Boulder Mountain area and the Blanket Glacier Area is included in Figure 1919.
Work completed by Heiko Wittmer (UBC, unpubl. data) based on telemetry data
from this study, as well as data from the Clearwater and Columbia forest districts,
indicate that there are three caribou herds that range in the Salmon Arm Forest
District (Figure 1717). Caribou in the Seymour river area (Figure 1818) are part of
the Columbia-North herd, which extends into the Clearwater Forest District and
Columbia Forest districts. Caribou that occupy the Boulder Mountain and Queest
Mountain areas (north of the Eagle River in Figure 1919) are part of the Frisby –
Boulder herd that extends into the Columbia Forest District. In the area south of the
Eagle River (approximates the route of the Trans-Canada highway), the only
available telemetry data are from a single collared female caribou. No caribou in this
small group had been collared in the past 15 years, and these caribou are assumed
to be isolated from caribou to the north and east. In one year of monitoring, the
largest number of caribou seen in this group is 6 caribou including 2 calves on
February 5, 2003. No caribou have been located in the Pukeashun Mountain area.
The Pukeashun Mt. area was searched in early and late winter of this year and no
caribou or tracks were seen. There was extensive tracking by snowmobilers in the
area.
19
Figure 1717. Kernel Home Range (90%) of caribou in herds delineated using
telemetry data (Heiko Wittmer, UBC, unpubl. data).
20
Figure 1818. Caribou locations by season for caribou monitored since 2000 in the
Seymour River area.
21
Figure 1919. Locations for caribou in the Boulder Mtn. - Queest Mtn. area and the
Blanket Glacier area. Each polygon represents the inter-annual home range of an
individual animal.
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6.0 Discussion
6.1
Habitat Utilization
Seip (1990) found that caribou in more rugged terrain used lower elevation ICH
forests during early winter, while caribou in highland areas, where terrain is more
subdued, used ESSF forests during early winter. In the Columbia Mountains where
terrain is very rugged, caribou selected strongly for low elevations during the early
winter period (Apps et al. 2001). Caribou in this study area showed an intermediate
pattern. They shifted to relatively lower elevations during early winter, but did not
appear to avoid higher elevations or sub-alpine fir stands. Terrain in the study area
is intermediate between the terrain in the Columbia Mountains and the Shuswap
Highland.
During early winter, most locations were on gentle terrain (20-40% slope), in
older (age class 8-9) Balsam, Spruce, Hemlock, Cedar or Douglas Fir leading
stands. Caribou were located in clearcuts, but less often than the availability of these
stands predicts. Caribou move to lower elevations during the snow accumulation
period to access alternative forage such as lichen litterfall, shrubs and lichen on
standing trees (Simpson et al. 1997). In high snowfall areas, caribou may be forced
to lower elevations due to the high costs of locomotion in an unconsolidated snow
pack, and the limited availability of arboreal lichen on standing trees at a height
available to caribou (Apps et al.2001). Work in the Clearwater Forest District
indicates that early winter home ranges are the largest of seasonal home ranges.
Resources during this period may be sparsely or patchily distributed (such as
windfall), and the cost of locomotion during early winter is higher, making the
maintenance of early winter habitat critical.
Caribou were usually located in stands with moderate to high canopy closure
during early winter. Research based on ground trailing of caribou, in the Columbia
and Clearwater Forest Districts, indicates that caribou using the ICH in early winter
regularly forage on boxwood (Pachistima myrsinites) and small forbs, lichen litterfall
and lichen on fallen trees. Access to these types of forage is likely dependent on
snow interception. Early winter foraging in the ESSF is currently being investigated
in the Clearwater forest district, but anecdotal information indicates lichen litterfall
and arboreal lichen on standing and fallen trees may be important sources of forage.
Caribou moved to higher elevations during late winter. This pattern is typical for
caribou across south-eastern BC (Stevenson et al. 2001). During late winter the
snow pack is consolidated and deep enough to provide access to arboreal lichens
(Simpson et al. 1997) that occur only above the maximum snowpack height (Goward
1998). Most locations were on gentle terrain (more so than during early winter). In
forested areas, caribou were usually located in old Balsam leading stands. Most
locations were in stands of low to moderate crown closure. A large proportion of
locations during this period were recorded in the alpine or sub-alpine indicating
conflicts with forestry interests and caribou range are less likely during this season
than during early winter. However, desirable snowmobile areas conflict directly with
late winter caribou habitat, and this activity may displace caribou in some areas
23
(Simpson 1987). High elevation road building for timber extraction is facilitating
snowmobile access to important late winter habitat.
During spring, caribou used a broad range of elevations that included the subalpine, ESSF and ICH. Caribou were primarily located in Spruce or Balsam stands,
but also used Cedar, Hemlock and Cedar stands. Caribou use a broad range of
habitat types during this season including clearcuts, slidepaths, riparian wetlands
and meadows. At high elevations, caribou likely continue to forage on arboreal
lichens, while at lower elevations and in snow-free areas they may be feeding on
new growth (Seip 1990). In forested areas caribou were primarily located in older
stands, but were also located in immature and semi-mature stands.
During calving, most locations were at higher elevations and in steeper terrain.
This pattern may be explained by the need to minimize the risk of calf predation, by
choosing calving areas where predators are less likely to be found (Simpson et al.
1997).
During summer, caribou shifted to mid to upper elevations including the alpine
and sub-alpine. Most locations were on low to moderate slopes. In forested areas,
caribou were usually located in mature or old stands of moderate to high canopy
closure. Caribou feed on a variety of forbs, grasses, shrubs and lichen during
summer (Seip 1990).
These results are preliminary; continued monitoring will allow for a more detailed
analysis of habitat use by caribou in this area. Future analysis should consider
variation in habitat use between individuals and a method to confirm selection of
habitat variables. In general, results from this data were similar to those presented in
Apps et al. 2001.
6.2
Distribution and home range
None of the monitored caribou spend all of their time in the Salmon Arm
Forest district, highlighting the need for co-operative management of caribou habitat
with similar organizations in the adjacent Clearwater and Columbia Forest Districts.
Caribou in the Seymour River area range into all three districts and are part of the
Columbia North herd, which occupies the area along Lake Revelstoke north to the
Mica Creek area. Censuses conducted in 2002 (48 animals) and 2003 (60 animals)
have found a relatively large number of caribou in the upper Seymour and Ratchford
drainages and immediately adjacent portions of the other two forest districts,
suggesting that this area may be an important hub for caribou with an influence that
extends over a greater area. The RMZ boundaries in this area have captured most
of the caribou locations. The exception is in the headwaters of the Anstey River and
along Myoff Creek where some late and early winter habitat use outside the
boundary of the RMZ has been recorded. Caribou may also be crossing the
Seymour River and Ratchford Creek downstream of the current RMZ boundary.
Snowmobilers are accessing prime caribou habitat in the Mt. Grace area via a
high elevation clearcut from the Seymour River. Given the potential impact of
increased use by snowmobiles, planning to avoid facilitating access, and managing
access once roads are in place, should be a high priority in caribou habitat.
Caribou that occupy the Queest and Boulder Mountain area are part of the
Frisby-Boulder Herd that extends into the Columbia Forest District. The RMZ
24
boundaries in this area have captured most of the known caribou locations. Caribou
in this herd have very little late winter habitat available to them that is not being
heavily used by snowmobilers (Frisby Ridge, Queest, Boulder, Eagle Pass Mtn.). In
the Queest mountain area, snowmobilers are using an extensive road and clearcut
system to access caribou habitat. They are not limiting use to open areas, and old
caribou tracks are often overlain with snowmobile tracks in forested areas
demonstrating the lack of spatial separation. If snowmobiling is to continue in this
area, then management and snowmobiler education plans should try to limit access
to the sub-alpine and alpine by using the established track, rather than straying into
the forest where they are more likely to encounter caribou. However, even with such
measures, there is very little of the Queest mountain snowmobile area that is not
also considered late winter caribou habitat and the potential impact of this activity on
caribou should be considered.
The small group of caribou south of the Trans-Canada highway appears to be
doing relatively well (given their extraordinarily small numbers). Two calves were
seen in the group this February. The collared female was located in the Joss
Mountain area, outside of the current RMZ boundary during early winter. Current
telemetry information indicates this herd is small and isolated and is therefore of
particular concern.
Besides continued monitoring to identify changes in behaviour, population
size, and distribution, future work should identify probable movement routes across
major valleys to confirm corridor placements. The Pukeashun Mountain area should
continue to be monitored in winter to check for caribou use.
7.0 References
DeMarchi, D. 1996. The Ecoregions of British Columbia. Ministry of Environment,
Lands and Parks. Victoria, B.C.
Furk. K. , J. Surgenor, B. McLellan. 2002. Forest attributes associated with mountain
caribou early winter feeding sites in the North Thompson Watershed of BC. Ministry
of Water, Land and Air Protection. Kamloops.
Furk, K. 2003. Survival rates and sources of mortality for mountain caribou in the
Clearwater and Salmon Arm Forest Districts: Preliminary report from telemetry data.
Unpublished.
Goward T. 1998. Observations on the ecology of the lichen genus Bryoria in high
elevation conifer forests. Canadian Field-Naturalist 112:496-501.
Simpson, K. 1987. The effects of snowmobiling on winter range use by mountain
caribou. British Columbia Ministry of Environment and Parks Wildlife Working Report
WR-25.
Seip, D. R. 1990. Ecology of woodland caribou in Wells Gray Provincial Park. British
Columbia Ministry of Environment Wildlife Bulletin B-68.
25
Simpson, K, E. Terry and D. Hamilton. 1997. Toward a Mountain Caribou
Management Strategy for British Columbia- Habitat requirements and subpopulation
status. British Columbia Ministry of Environment and Parks Wildlife Bulletin B-57.
Stevenson, S., H.M. Armleder, M. Jull, D. King, B.M. McLellan, D.S. Coxsyn. 2001.
Mountain Caribou in Managed Forests: Recommendations for Managers, second
edition. British Columbia Ministry of Environment, Lands and Parks. Wildlife Report
no. R-26.
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