Survival of radio-collared caribou (Rangifer tarandus caribou) from the George River herd, Nouveau-Québec – Labrador

1990 ◽  
Vol 68 (2) ◽  
pp. 276-283 ◽  
Author(s):  
Brian J. Hearn ◽  
Stuart N. Luttich ◽  
Michel Crête ◽  
Maria B. Berger
Keyword(s):  
Cause Of Death ◽  
Rangifer Tarandus ◽  
Survival Rates ◽  
Rangifer Tarandus Caribou ◽  
Annual Survival ◽  
Lower Survival ◽  
Fecundity Rate ◽  
Rate Of Increase ◽  
George River ◽  
Age And Sex

Between September 1983 and June 1987, 175 caribou (Rangifer tarandus caribou) from the George River caribou herd were captured and radio-collared. By October 1987, 42 of those had died: 15 were apparently killed by predators, 8 were legally shot, 4 appeared to have died proximally from malnutrition, 1 died from an accident, and cause of death could not be determined for 14 others. Seasonal and annual survival rates were estimated most precisely for adult (≥ 24 months) females, but a consistent trend towards lower survival at the end of the study period was evident in all age and sex groups. Decreasing summer survival was responsible for the lowering of annual survival rates, as winter survival was relatively constant over the study period. Using our calculated age-specific survival rates, and estimates of age-specific fecundity, the survival–fecundity rate of increase (rs) for the female segment of the herd was 0.12 for 1983–1984 and −0.01 for 1986–1987. Decreasing summer survival thus appears to have been of greatest importance in reducing rs to zero and halting the growth of the herd. Density-dependent mechanisms acting on the George River caribou herd appear different from those described for caribou herds regulated by winter forage.

scholarly journals Population dynamics of the endangered mountain ecotype of woodland caribou (Rangifer tarandus caribou) in British Columbia, Canada

2020 ◽  
Author(s):  
Heiko Wittmer ◽  
BN McLellan ◽  
DR Seip ◽  
JA Young ◽  
TA Kinley ◽  
...  
Keyword(s):  
British Columbia ◽  
Population Dynamics ◽  
Rangifer Tarandus ◽  
Population Decline ◽  
Survival Rates ◽  
Adult Survival ◽  
Rangifer Tarandus Caribou ◽  
Vital Rates ◽  
Woodland Caribou ◽  
Annual Survival

We used census results and radiotelemetry locations of >380 collared individuals sampled over the entire distribution of the endangered mountain ecotype of woodland caribou (Rangifer tarandus caribou (Gmelin, 1788)) in British Columbia, Canada, to delineate population structure and document the size and trend of the identified populations. We also describe the spatial pattern of decline and the causes and timing of adult mortality and provide estimates of vital rates necessary to develop a population viability analysis. Our results indicate that the abundance of mountain caribou in British Columbia is declining. We found adult female annual survival rates below annual survival rates commonly reported for large ungulates. The major proximate cause of population decline appears to be predation on adult caribou. Spatial patterns of population dynamics revealed a continuous range contraction and an increasing fragmentation of mountain caribou into smaller, isolated subpopulations. The population fragmentation process predominantly occurs at the outer boundaries of the current distribution. Our results indicate that recovery strategies for mountain caribou should be directed at factors contributing to the fragmentation and isolation of mountain caribou populations as well as management strategies aimed at increasing adult survival. © 2005 NRC Canada.

scholarly journals Population dynamics of the endangered mountain ecotype of woodland caribou (Rangifer tarandus caribou) in British Columbia, Canada

2020 ◽  
Author(s):  
Heiko Wittmer ◽  
BN McLellan ◽  
DR Seip ◽  
JA Young ◽  
TA Kinley ◽  
...  
Keyword(s):  
British Columbia ◽  
Population Dynamics ◽  
Rangifer Tarandus ◽  
Population Decline ◽  
Survival Rates ◽  
Adult Survival ◽  
Rangifer Tarandus Caribou ◽  
Vital Rates ◽  
Woodland Caribou ◽  
Annual Survival

We used census results and radiotelemetry locations of >380 collared individuals sampled over the entire distribution of the endangered mountain ecotype of woodland caribou (Rangifer tarandus caribou (Gmelin, 1788)) in British Columbia, Canada, to delineate population structure and document the size and trend of the identified populations. We also describe the spatial pattern of decline and the causes and timing of adult mortality and provide estimates of vital rates necessary to develop a population viability analysis. Our results indicate that the abundance of mountain caribou in British Columbia is declining. We found adult female annual survival rates below annual survival rates commonly reported for large ungulates. The major proximate cause of population decline appears to be predation on adult caribou. Spatial patterns of population dynamics revealed a continuous range contraction and an increasing fragmentation of mountain caribou into smaller, isolated subpopulations. The population fragmentation process predominantly occurs at the outer boundaries of the current distribution. Our results indicate that recovery strategies for mountain caribou should be directed at factors contributing to the fragmentation and isolation of mountain caribou populations as well as management strategies aimed at increasing adult survival. © 2005 NRC Canada.

scholarly journals Population dynamics of the endangered mountain ecotype of woodland caribou (Rangifer tarandus caribou) in British Columbia, Canada

2005 ◽  
Vol 83 (3) ◽  
pp. 407-418 ◽  
Author(s):  
Heiko U Wittmer ◽  
Bruce N McLellan ◽  
Dale R Seip ◽  
James A Young ◽  
Trevor A Kinley ◽  
...  
Keyword(s):  
British Columbia ◽  
Population Dynamics ◽  
Rangifer Tarandus ◽  
Population Decline ◽  
Survival Rates ◽  
Adult Survival ◽  
Rangifer Tarandus Caribou ◽  
Vital Rates ◽  
Woodland Caribou ◽  
Annual Survival

We used census results and radiotelemetry locations of >380 collared individuals sampled over the entire distribution of the endangered mountain ecotype of woodland caribou (Rangifer tarandus caribou (Gmelin, 1788)) in British Columbia, Canada, to delineate population structure and document the size and trend of the identified populations. We also describe the spatial pattern of decline and the causes and timing of adult mortality and provide estimates of vital rates necessary to develop a population viability analysis. Our results indicate that the abundance of mountain caribou in British Columbia is declining. We found adult female annual survival rates below annual survival rates commonly reported for large ungulates. The major proximate cause of population decline appears to be predation on adult caribou. Spatial patterns of population dynamics revealed a continuous range contraction and an increasing fragmentation of mountain caribou into smaller, isolated subpopulations. The population fragmentation process predominantly occurs at the outer boundaries of the current distribution. Our results indicate that recovery strategies for mountain caribou should be directed at factors contributing to the fragmentation and isolation of mountain caribou populations as well as management strategies aimed at increasing adult survival.

Fascioloides magna (Trematoda) in woodland caribou (Rangifer tarandus caribou) of the George River herd, Labrador

1988 ◽  
Vol 66 (2) ◽  
pp. 475-479 ◽  
Author(s):  
Murray W. Lankester ◽  
Stu Luttich
Keyword(s):  
Rangifer Tarandus ◽  
Age Groups ◽  
Liver Weight ◽  
Rangifer Tarandus Caribou ◽  
Woodland Caribou ◽  
Intensity Of Infection ◽  
Fascioloides Magna ◽  
The Mean ◽  
George River ◽  
Liver Flukes

Fifty-eight percent of woodland caribou (Rangifer tarandus caribou) of the George River herd, Labrador, were infected with up to 110 giant American liver flukes (Fascioloides magna). The prevalence and intensity of infection did not differ between 2 sampling years or between sexes. Prevalence tended to increase with age while intensity did not differ among age groups. Liver weight increased with intensity of infection but condition, as measured by the mean depth of back fat, did not differ between infected and uninfected animals. Caribou must be considered a suitable host of F. magna since the growth and maturation of the parasite and lesions produced in Rangifer resemble those in deer and wapiti.

Rates of increase in age-structured populations: a lesson from the European harbour seals

2002 ◽  
Vol 80 (9) ◽  
pp. 1498-1510 ◽  
Author(s):  
Tero Härkönen ◽  
Karin C Harding ◽  
Mads-Peter Heide-Jørgensen
Keyword(s):  
Survival Rates ◽  
Natural Populations ◽  
Structured Populations ◽  
Population Increase ◽  
Biological Removal ◽  
Harbour Seals ◽  
Rate Of Increase ◽  
Population Structures ◽  
Age Structured ◽  
Age And Sex

Behavioural differences among population segments coupled with the transient dynamics of perturbed population structures lead to severely biased estimates of the intrinsic rates of increase in natural populations. This phenomenon is expected to occur in most populations that are structured by age, sex, state, or rank. The 1988 epizootic in European harbour seals (Phoca vitulina) perturbed the population composition radically. Detailed documentation of mass mortality, 20 years of population surveys, and data on age- and sex-specific behaviour were used to quantify biases in the observed rate of increase (λobs.), which in many areas substantially exceeded the "maximum rate of increase". This is serious, since λobs. is a key parameter, for example, in estimating potential biological removal or modelling population dynamics. For populations where the underlying age and sex composition is unknown, we suggest that data on fecundity and survival rates be used to find the upper theoretical rate of population increase. We found that the intrinsic rates of increase (λ1) in populations of true seals with even sex ratios and stable age structures cannot exceed 13% per year (λ1max. = 1.13). Frequently reported larger values are indicative of nonstable population structures or populations affected by migrations.

Physical and reproductive characteristics of an expanding woodland caribou population (Rangifer tarandus caribou) in northern Labrador

1981 ◽  
Vol 59 (10) ◽  
pp. 1929-1940 ◽  
Author(s):  
G. R. Parker
Keyword(s):  
Rangifer Tarandus ◽  
Adult Mortality ◽  
Lean Body Weight ◽  
High Survival ◽  
Rangifer Tarandus Caribou ◽  
River Population ◽  
Female Ratio ◽  
Reproductive Maturity ◽  
Fat Reserves ◽  
George River

One hundred and fifty-nine caribou (Rangifer tarandus caribou) were collected from the area of precalving distribution of the George River population in northern Labrador between April 3 and 15, 1980. The sample revealed that caribou of northern Labrador reach physical and reproductive maturity earlier than most other free-ranging caribou populations in North America. Females attained mature values for lean body weight and shoulder height by 34 months and for total body length, heart girth, and mandible length by 46 months. Pregnancy rates for females 22, 34, and 46 months and older were 43, 90, and 95%, respectively. Measurements of fat reserves showed George River females to be in superior physical condition during spring migration than caribou on mainland Northwest Territories. Fat reserves, however, were substantially less than comparable values for females collected from the same population in March, 1976. The calf: pregnant female ratio was 42:100, suggesting a 1st year rate of mortality of approximately 58%. The most common internal parasites were Cysticercus tenuicollis and Fascioloides magna. It is concluded that the recent growth of the George River population has resulted from early female physical and reproductive maturity, low adult mortality, and high survival of calves.

scholarly journals Metabolic rate is negatively linked to adult survival but does not explain latitudinal differences in songbirds

2019 ◽  
Author(s):  
Andy J. Boyce ◽  
James C. Mouton ◽  
Penn Lloyd ◽  
Blair O. Wolf ◽  
Thomas E. Martin
Keyword(s):  
Metabolic Rate ◽  
Survival Rates ◽  
Latitudinal Variation ◽  
Adult Survival ◽  
Metabolic Rates ◽  
Direct Effects ◽  
Physiological Mechanisms ◽  
Annual Survival ◽  
Lower Survival

ABSTRACTSurvival rates vary dramatically among species and predictably across latitudes, but causes of this variation are unclear. The rate of living hypothesis posits that physiological damage from metabolism causes species with faster metabolic rates to exhibit lower survival rates. However, whether increased survival commonly observed in tropical and south temperate latitudes is associated with slower metabolic rate remains unclear. We compared metabolic rates and annual survival rates across 46 species that we measured, and 147 species from literature data across northern, southern, and tropical latitudes. High metabolic rates were associated with lower survival but latitude had substantial direct effects on survival independent of metabolism. The inability of metabolic rate to explain latitudinal variation in survival suggests 1) that species may evolve physiological mechanisms that mitigate physiological damage from cellular metabolism, and 2) a larger role of extrinsic environmental, rather than intrinsic metabolic, causes of latitudinal differences in mortality.

Seeking sanctuary: the neonatal calving period among central mountain woodland caribou (Rangifer tarandus caribou)

2016 ◽  
Vol 94 (12) ◽  
pp. 837-851 ◽  
Author(s):  
B.R. Nobert ◽  
S. Milligan ◽  
G.B. Stenhouse ◽  
L. Finnegan
Keyword(s):  
Habitat Selection ◽  
Rangifer Tarandus ◽  
Survival Rates ◽  
High Elevation ◽  
Rangifer Tarandus Caribou ◽  
Woodland Caribou ◽  
Seismic Line ◽  
Data Set ◽  
Movement Rates

Woodland caribou (Rangifer tarandus caribou (Gmelin, 1788)) populations have declined throughout their range. With the goal of better understanding habitat selection and fidelity during the neonatal calving period (0–4 weeks), we applied a noninvasive method that estimates calving events and subsequent survival based on changes in movement rates among GPS-collared female caribou. We examined a long-term GPS-collar data set (1998–2014) collected from 81 adult female caribou in two central mountain herds in Alberta and British Columbia, Canada. Although we were unable to validate our results with aerial surveys and pregnancy tests, our estimates of parturition rates, survival rates, calving dates, and habitat selection were consistent with previous studies. We identified 83 calving sites. Female caribou selected calving sites and postparturition habitat on high-elevation ridgetops with gradual slopes and avoided anthropogenic linear features. Female caribou displayed low fidelity to interannual calving ranges with a mean distance of 8.7 km between calving ranges. Fidelity was lower in areas with high seismic-line density. Conservation of high-elevation habitat with limited anthropogenic disturbance is likely to provide the greatest benefit to central mountain caribou during the neonatal calving period, and represents a potential management strategy for population recovery efforts.

scholarly journals Longevity and Mortality of Boreal Woodland Caribou (Rangifer tarandus caribou) of the Dehcho Region, Northwest Territories

2016 ◽  
Vol 130 (3) ◽  
pp. 222
Author(s):  
Nicholas C Larter ◽  
Danny G Allaire
Keyword(s):  
Cause Of Death ◽  
Biological Samples ◽  
Rangifer Tarandus ◽  
Time Of Death ◽  
Rangifer Tarandus Caribou ◽  
Age At Death ◽  
Woodland Caribou ◽  
Commercial Laboratory ◽  
Adult Females ◽  
Cementum Analysis

As part of an ongoing study of the ecology of boreal Woodland Caribou (Rangifer tarandus caribou), we investigated death sites of collared caribou to collect biological samples and determine a cause of death. The teeth collected from 25 adult females that had died since being radio collared were aged by cementum analysis. The age at death for one caribou was 22 years; this was only the second caribou tooth among 42 776 aged at a commercial laboratory found to be that old. An additional six of the 25 caribou were 13–17 years old at time of death. All but one of these seven female caribou had calved at least once during the periodthey were radio collared and monitored.

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