Characteristics of Early-Winter Caribou, <em>Rangifer tarandus caribou</em>, Feeding Sites in the Southern Purcell Mountains, British Columbia

Mountain Caribou are a rare ecotype of Woodland Caribou (Rangifer tarandus caribou) inhabiting the high-snowfall region of southeastern British Columbia, and are defined by their late-winter reliance on arboreal hair lichen of the genus Bryoria. During early winter, there is considerable variation in habitat use among populations. We snow-trailed Caribou in the southern Purcell Mountains during early winter to determine foraging patterns for the Purcell population. When snow was ≤51 cm deep, Caribou fed on Grouseberry (Vaccinium scoparium), the terrestrial lichen Cladonia, and arboreal lichens of the genus Bryoria. When snow was ≥62 cm deep, they ate exclusively arboreal lichens. In both periods, Caribou ate arboreal lichen from essentially every downed tree or branch encountered and fed with a higher intensity at downed trees than standing trees. During the low-snow period, Caribou fed at fewer trees but used those with greater lichen abundance, and fed more intensively at each, compared to the deep-snow period. In comparison to trees occurring on the foraging path but at which Caribou did not feed, those from which arboreal lichen was foraged intensively were of larger diameter, had greater lichen abundance, and were more likely to be Subalpine Fir (Abies lasiocarpa) or Engelmann Spruce (Picea engelmannii) and less likely to be Whitebark Pine (Pinus albicaulis), Lodgepole Pine (P. contorta) or Alpine Larch (Larix lyalli). The shift in diet between the low-snow and deep-snow periods reflected two modes of foraging within the early winter period, distinct from one another and apparently also distinct from the late-winter season. Management for early-winter habitat will require retention of some commercially significant forest across extensive areas, both near the subalpine forest – subalpine parkland ecotone and lower in the subalpine forest.

Download Full-text

Factors influencing variation in site fidelity of woodland caribou (Rangifer tarandus caribou) in southeastern British Columbia

10.26686/wgtn.12971867.v1 ◽

2020 ◽

Author(s):

Heiko Wittmer ◽

B McLellan ◽

F Hovey

Keyword(s):

British Columbia ◽

Site Fidelity ◽

Rangifer Tarandus ◽

Snow Accumulation ◽

Limiting Factors ◽

Late Winter ◽

Behavioural Plasticity ◽

Rangifer Tarandus Caribou ◽

Early Winter ◽

Woodland Caribou

Where predation is a major limiting factor, it has been postulated that woodland caribou (Rangifer tarandus caribou (Gmelin, 1788)) reduce movements to minimize contact with predators and exhibit fidelity to seasonal ranges. We examined fidelity behaviour within season and among years of woodland caribou based on locations of 65 radio-collared individuals in British Columbia, Canada. We used average linear distances between all possible pairs of radiolocations of individuals to assess fidelity. Among-year interlocation distances were similar to within-season interlocation distances during summer, indicating that caribou did not shift their distribution during seasons when they were most vulnerable to predation. Among-year interlocation distances were significantly greater than within-season interlocation distances during both early winter and late winter, indicating that individual caribou shifted their distribution among winters. The amount that an individual's distribution shifted among winters varied among and within individuals over different years. During early winter this behavioural plasticity was correlated with snow accumulation, with individuals having greater interlocation distances in years with high snow accumulation. Our results indicate that site fidelity outside the calving season is unlikely solely influenced by predator avoidance. We suggest that seasonal shifts in the importance of limiting factors vary from predation in summer to food in winter. © 2006 NRC.

Download Full-text

Factors influencing variation in site fidelity of woodland caribou (Rangifer tarandus caribou) in southeastern British Columbia

Canadian Journal of Zoology ◽

10.1139/z06-026 ◽

2006 ◽

Vol 84 (4) ◽

pp. 537-545 ◽

Cited By ~ 33

Author(s):

Heiko U. Wittmer ◽

Bruce N. McLellan ◽

Frederick W. Hovey

Keyword(s):

British Columbia ◽

Site Fidelity ◽

Rangifer Tarandus ◽

Snow Accumulation ◽

Limiting Factors ◽

Late Winter ◽

Behavioural Plasticity ◽

Rangifer Tarandus Caribou ◽

Early Winter ◽

Woodland Caribou

Where predation is a major limiting factor, it has been postulated that woodland caribou ( Rangifer tarandus caribou (Gmelin, 1788)) reduce movements to minimize contact with predators and exhibit fidelity to seasonal ranges. We examined fidelity behaviour within season and among years of woodland caribou based on locations of 65 radio-collared individuals in British Columbia, Canada. We used average linear distances between all possible pairs of radiolocations of individuals to assess fidelity. Among-year interlocation distances were similar to within-season interlocation distances during summer, indicating that caribou did not shift their distribution during seasons when they were most vulnerable to predation. Among-year interlocation distances were significantly greater than within-season interlocation distances during both early winter and late winter, indicating that individual caribou shifted their distribution among winters. The amount that an individual’s distribution shifted among winters varied among and within individuals over different years. During early winter this behavioural plasticity was correlated with snow accumulation, with individuals having greater interlocation distances in years with high snow accumulation. Our results indicate that site fidelity outside the calving season is unlikely solely influenced by predator avoidance. We suggest that seasonal shifts in the importance of limiting factors vary from predation in summer to food in winter.

Download Full-text

Factors influencing variation in site fidelity of woodland caribou (Rangifer tarandus caribou) in southeastern British Columbia

10.26686/wgtn.12971867 ◽

2020 ◽

Author(s):

Heiko Wittmer ◽

B McLellan ◽

F Hovey

Keyword(s):

British Columbia ◽

Site Fidelity ◽

Rangifer Tarandus ◽

Snow Accumulation ◽

Limiting Factors ◽

Late Winter ◽

Behavioural Plasticity ◽

Rangifer Tarandus Caribou ◽

Early Winter ◽

Woodland Caribou

Download Full-text

Early-winter diet of woodland caribou in relation to snow accumulation, Selkirk Mountains, British Columbia, Canada

Canadian Journal of Zoology ◽

10.1139/z90-372 ◽

1990 ◽

Vol 68 (12) ◽

pp. 2691-2694 ◽

Cited By ~ 20

Author(s):

Eric M. Rominger ◽

John L. Oldemeyer

Keyword(s):

British Columbia ◽

Rangifer Tarandus ◽

Transition Period ◽

Management Strategies ◽

Snow Accumulation ◽

Late Winter ◽

Early Winter ◽

Accumulation Rates ◽

Woodland Caribou ◽

Selkirk Mountains

Woodland caribou (Rangifer tarandus caribou) in the southern Selkirk Mountains of British Columbia shift from a diet of primarily vascular taxa during snow-free months to an arboreal lichen – conifer diet during late winter. We present evidence that caribou diets, during the early-winter transition period, are influenced by snow accumulation rates. Caribou shift to an arboreal lichen – conifer diet earlier during winters of rapid snow accumulation and forage extensively on myrtle boxwood (Pachistima myrsinites), an evergreen shrub, and other vascular plants during years of slower snow accumulation. The role of coniferous forage in early-winter food habits is examined. Forest management strategies can be developed to provide habitat that will enable caribou to forage in response to varying snow accumulation rates.

Download Full-text

The influence of variable snowpacks on habitat use by mountain caribou

Rangifer ◽

10.7557/2.27.4.323 ◽

2007 ◽

Vol 27 (4) ◽

pp. 93 ◽

Cited By ~ 6

Author(s):

Trevor A. Kinley ◽

Trevor Goward ◽

Bruce N. McLellan ◽

Robert Serrouya

Keyword(s):

Rangifer Tarandus ◽

Management Strategies ◽

Western Hemlock ◽

Late Winter ◽

Abies Lasiocarpa ◽

Rangifer Tarandus Caribou ◽

Climatic Region ◽

Subalpine Fir ◽

Foraging Modes ◽

High Elevations

Mountain caribou (Rangifer tarandus caribou) in southeastern British Columbia subsist for most of the winter on arboreal hair lichen, mostly Bryoria spp. Foraging occurs mainly in old subalpine fir (Abies lasiocarpa) forests near treeline. Here, the lower limit of Bryoria in the canopy is dictated by snowpack depth because hair lichens die when buried in snow. Bryoria is often beyond the reach of caribou in early winter, prompting caribou to move downslope to where lichen occurs lower in the canopy and other foraging modes are possible. Snowpacks are normally deep enough by late winter that caribou can reach Bryoria where it is most abundant, at high elevations. Extending this to inter-annual comparisons, Bryoria should be less accessible during late winter of low-snow years following normal winters, or of normal to low-snow years after deep-snow winters. We hypothesized that when maximum snowpack in late winter is low relative to the deepest of the previous 5 years, mountain caribou will use lower elevations to facilitate foraging (“lichen-snow-caribou” or LSC hypothesis). We tested this with late-winter data from 13 subpopulations. In the dry climatic region generally and for minor snowfall differences in wet and very wet regions, caribou did not shift downslope or in fact were at higher elevations during relatively low-snow years, possibly reflecting the ease of locomotion. The LSC hypothesis was supported within wet and very wet regions when snowpacks were about 1 m or more lower than in recent years. Elevation declined by 300 m (median) to 600 m (25th percentile) for snowpack differences of at least 1.5 m. Greater use of lodgepole pine and western hemlock stands sometimes also occurred. Management strategies emphasizing subalpine fir stands near treeline should be re-examined to ensure protection of a broader range of winter habitats used by caribou under variable snowpack conditions.

Download Full-text

Arboreal forage lichens in partial cuts – a synthesis of research results from British Columbia, Canada

Rangifer ◽

10.7557/2.27.4.342 ◽

2007 ◽

Vol 27 (4) ◽

pp. 155 ◽

Cited By ~ 8

Author(s):

Susan K. Stevenson ◽

Darwyn S. Coxson

Keyword(s):

British Columbia ◽

Growth Rates ◽

Rangifer Tarandus ◽

Basal Area ◽

Physiological Data ◽

Abies Lasiocarpa ◽

Partial Cutting ◽

Winter Habitat ◽

Dispersal Capability ◽

Alectoria Sarmentosa

The mountain ecotype of the woodland caribou (Rangifer tarandus caribou) is highly dependent on the arboreal hair lichens Bryoria spp. and Alectoria sarmentosa during winter. In parts of British Columbia, partial-cutting silvicultural systems have been used in an effort to provide continuously usable winter habitat for mountain caribou, while allowing some timber removal. We reviewed available information about the changes in hair lichens after partial cutting in Engelmann spruce (Picea engelmannii) – subalpine fir (Abies lasiocarpa) forests of British Columbian and Idaho. Generally, abundance of Bryoria spp. in the lower canopy of individual residual trees increases with increased exposure after partial cutting, until the new regeneration begins to shelter the lower canopy of the residuals. Heavy basal area removal, however, results in low lichen availability at the stand level for many years. Abundance of Bryoria on the regeneration is low, and appears to be limited largely by the structure of the young trees, not by lichen dispersal, although dispersal capability may be limiting in Alectoria. Both distributional and physiological data suggest that Bryoria is intolerant of prolonged wetting, and that increased ventilation, rather than increased light, accounts for enhanced Bryoria abundance in the partial cuts. Alectoria sarmentosa reaches its physiological optimum in the lower canopy of unharvested stands; its growth rates are somewhat reduced in the more exposed environment of partial cuts. Both genera are capable of rapid growth: over a 7-year period, individual thalli of A. sarmentosa and Bryoria spp. (excluding those with a net biomass loss due to fragmentation) in an unlogged stand more than tripled their biomass. Calculated growth rates, as well as dispersal potential, are influenced by fragmentation. Bryoria produces more abundant, but smaller, fragments than Alectoria, and fragmentation in both genera increases in partial cuts. In subalpine mountain caribou habitat, partial-cutting prescriptions that enhance exposure of residual trees while keeping basal area removal low will maintain forage best. Regeneration management should focus on maintaining ventilation in the lower canopy of the residual stand.

Download Full-text

Using ultrasound measurements of rump fat to assess nutritional condition of woodland caribou in northern British Columbia, Canada

Rangifer ◽

10.7557/2.27.4.351 ◽

2007 ◽

Vol 27 (4) ◽

pp. 249 ◽

Cited By ~ 9

Author(s):

David D. Gustine ◽

Katherine L. Parker ◽

Douglas C. Heard

Keyword(s):

British Columbia ◽

Rangifer Tarandus ◽

Winter Season ◽

Nutritional Condition ◽

Invasive Technique ◽

Rangifer Tarandus Caribou ◽

Woodland Caribou ◽

Portable Ultrasound ◽

Ultrasound Machine ◽

Non Invasive

Body reserves (fat and protein) of cervids are important to the reproductive success of individuals, and therefore may limit productivity of populations. We used a portable ultrasound machine to measure thickness of rump fat for 39 woodland caribou (Rangifer tarandus caribou) captured in the winters (January–February) of 2003 and 2004. We compared thickness of rump fat between pregnant and non-pregnant individuals in the Besa-Prophet drainage of northern British Columbia, Canada. Thirty-eight of the 39 females captured in British Columbia were adults and 34 of the adult caribou were pregnant (89.5 ± 5.1%, x– ± binomial SE). Pregnant individuals had more rump fat (0.60 ± 0.067 cm) than nonpregnant animals (0.20 ± 0.029 cm). Recognizing that deposition and mobilization of fat vary with age and possibly across the winter season, ultrasonography can be used as a non-invasive technique in the field to assist in estimating body fat of caribou.

Download Full-text

A synthesis of scale-dependent ecology of the endangered mountain caribou in British Columbia, Canada

Rangifer ◽

10.7557/2.28.1.150 ◽

2008 ◽

Vol 28 (1) ◽

pp. 33

Author(s):

Robert Serrouya ◽

Bruce N. McLellan ◽

Clayton D. Apps ◽

Heiko U. Wittmer

Keyword(s):

British Columbia ◽

Rangifer Tarandus ◽

Spatial Scales ◽

Management Strategies ◽

Population Level ◽

Limiting Factors ◽

Conservation Strategies ◽

Integrative Approach ◽

Rangifer Tarandus Caribou ◽

Multi Scale

Mountain caribou are an endangered ecotype of woodland caribou (Rangifer tarandus caribou) that live in highprecipitation, mountainous ecosystems of southeastern British Columbia and northern Idaho. The distribution and abundance of these caribou have declined dramatically from historical figures. Results from many studies have indicated that mountain caribou rely on old conifer forests for several life-history requirements including an abundance of their primary winter food, arboreal lichen, and a scarcity of other ungulates and their predators. These old forests often have high timber value, and understanding mountain caribou ecology at a variety of spatial scales is thus required to develop effective conservation strategies. Here we summarize results of studies conducted at three different spatial scales ranging from broad limiting factors at the population level to studies describing the selection of feeding sites within seasonal home ranges of individuals. The goal of this multi-scale review is to provide a more complete picture of caribou ecology and to determine possible shifts in limiting factors across scales. Our review produced two important results. First, mountain caribou select old forests and old trees at all spatial scales, signifying their importance for foraging opportunities as well as conditions required to avoid alternate ungulates and their predators. Second, relationships differ across scales. For example, landscapes dominated by roads and edges negatively affect caribou survival, but appear to attract caribou during certain times of the year. This juxtaposition of fine-scale behaviour with broad-scale vulnerability to predation could only be identified through integrated multi-scale analyses of resource selection. Consequently we suggest that effective management strategies for endangered species require an integrative approach across multiple spatial scales to avoid a focus that may be too narrow to maintain viable populations. Abstract in Norwegian / Sammendrag:Skala-avhengig økologi og truet fjellvillrein i Britisk ColumbiaFjellvillreinen i de nedbørsrike fjellområdene i sørøstre Britisk Columbia og nordlige Idaho som er en truet økotype av skogsreinen (Rangifer tarandus caribou), har blitt kraftig redusert både i utbredelse og antall. Mange studier har vist at denne økotypen er avhengig av vinterføden hengelav i gammel barskog hvor det også er få andre klovdyr og dermed få predatorer. Slik skog er også viktige hogstområder, og å forstå økologien til fjellvillreinen i forskjellige skaleringer er derfor nødvendig for å utvikle forvaltningsstrategier som kan berge og ta vare på denne reinen. Artikkelen gir en oversikt over slike arbeider: fra studier av begrensende faktorer på populasjonsnivå til studier av sesongmessige beiteplasser på individnivå. Hensikten er å få frem et mer helhetlig perspektiv på fjellvillreinen og finne hvordan de begrensende faktorene varierer etter skaleringen som er benyttet i studiet. Oversikten vår frembragte to viktige resultater; 1) Uansett skalering så velger dyrene gammel skog og gamle trær. 2) Dyrenes bruk av et område kan variere med benyttet skalering, for eksempel vil landskap utbygd med veier og hogstflater være ufordelaktig for overlevelsen, men synes likevel å kunne tiltrekke fjellvillreinen til visse tider av året. Forholdet mellom atferd ut fra fin-skalering og stor-skalering sårbarhet hva gjelder predasjon, ville kun blitt avdekket ved flere-skaleringsanalyse av hvordan ressursene benyttes. Ut fra dette foreslår vi at forvaltningsstrategier for truete bestander som eksempelvis fjellvillreinen, må baseres på tilnærminger ut fra ulike skaleringer for å hindre at et for snevert perspektiv kan begrense muligheten for vedvarende levedyktighet.

Download Full-text

Transition of the ENSO teleconnection to the Euro-Atlantic region from early to late winter: Role of the Indian Ocean

10.5194/egusphere-egu2020-11318 ◽

2020 ◽

Author(s):

Muhammad Adnan Abid ◽

Fred Kucharski ◽

Franco Molteni ◽

In-Sik Kang ◽

Adrian Tompkins ◽

...

Keyword(s):

Indian Ocean ◽

Winter Season ◽

Tropical Indian Ocean ◽

Late Winter ◽

Boreal Winter ◽

Early Winter ◽

Atlantic Region ◽

Atlantic Sector ◽

The Indian Ocean ◽

Circulation Anomalies

<p>El Ni&#241;o Southern Oscillation (ENSO) have a weak influence on the seasonal mean Euro-Atlantic circulation anomalies during the boreal winter (Dec-Feb) season. Therefore, monthly ENSO teleconnections to Euro-Atlantic region were studied during the boreal winter season for the period 1981-2015 using reanalysis and hindcast dataset. It is shown that the ENSO-forced signal to the Euro-Atlantic circulation anomalies does not persist throughout the boreal winter season. During earlier winter, a positive ENSO phase strongly enforces rainfall dipole anomalies in the tropical Indian Ocean, with increased rainfall over the western tropical Indian Ocean, and reduced in the eastern tropical Indian ocean. &#160;This Indian Ocean rainfall dipole weakens in late winter. During early winter, the Indian Ocean rainfall dipole modifies the subtropical South Asian jet (SAJET) which forces a wavenumber-3 response projecting spatially onto the positive North Atlantic Oscillation (NAO) pattern. On contrary, during late winter, the response in the Euro-Atlantic sector is dominated by the well-known ENSO wavetrain from the tropical Pacific region, involving Pacific North American (PNA) pattern anomalies that project spatially on the negative phase of the NAO. Atmospheric General Circulation Model (AGCM) numerical experiments forced with an Indian Ocean heating dipole anomaly support the hypothesis that the Indian Ocean modulates the SAJET that enforces the Rossby wave propagation to the Euro-Atlantic region in early winter. Moreover, the ECMWF-SEAS5 hindcast dataset reproduces the observed ENSO-forced inter-basin tropical teleconnections transition from early to late winter and their response to the Euro-Atlantic circulation anomalies quite well. Therefore, it is important to understand the tropical inter-basin transition, which may lead to improve the sub-seasonal to seasonal variability and predictability of the Euro-Atlantic circulation anomalies.&#160;</p>

Download Full-text

Comparison of seasonal habitat selection between threatened woodland caribou ecotypes in central British Columbia

Rangifer ◽

10.7557/2.27.4.325 ◽

2007 ◽

Vol 27 (4) ◽

pp. 111 ◽

Cited By ~ 4

Author(s):

Elena S. Jones ◽

Michael P. Gillingham ◽

Dale R. Seip ◽

Douglas C. Heard

Keyword(s):

British Columbia ◽

Habitat Use ◽

Rocky Mountains ◽

Vegetation Cover ◽

Rangifer Tarandus ◽

Late Winter ◽

Woodland Caribou ◽

Recovery Planning ◽

Specific Mapping ◽

Selection Of

Woodland caribou (Rangifer tarandus caribou) in British Columbia have been classified into ecotypes based on differences in use of habitat in winter. Although recovery planning focuses on ecotypes, habitat use and selection varies within ecotypes. Our objectives were to compare habitat use and selection among previously identified woodland caribou herds at the transition zone between northern (Moberly, Quintette, and Kennedy herds) and mountain (Parsnip herd) ecotypes in central British Columbia. We developed selection models for each herd in spring, calving, summer/fall, early and late winter. Topographic models best predicted selection by most herds in most seasons, but importance of vegetation-cover was highlighted by disproportionate use of specific vegetation-cover types by all caribou herds (e.g., in early winter, 75% of Kennedy locations were in pine-leading stands, 84% of Parsnip locations were in fir and fir-leading stands, and 87 and 96% of locations were in alpine for the Moberly and Quintette herds, respectively). Using a combination of GPS and VHF radio-collar locations, we documented some spatial overlap among herds within the year, but use of vegetation-cover types and selection of elevations, aspects, and vegetation-cover types differed among herds and within ecotypes in all seasons. Habitat use and selection were most similar between the two northern-ecotype herds residing on the eastern side of the Rocky Mountains. This research indicates that habitat use and selection by caribou herds in all seasons is more variable than ecotype classifications suggest and demonstrates the value of undertaking herd-specific mapping of critical habitat for woodland caribou.

Download Full-text