REGULAR ARTICLES / ARTICLES RÉGULIERSFactors affecting the distribution and transmission of Elaphostrongylus rangiferi (Protostrongylidae) in caribou (Rangifer tarandus caribou) of Newfoundland, Canada

2001 ◽  
Vol 79 (7) ◽  
pp. 1265-1277 ◽  
Author(s):  
Mark C Ball ◽  
Murray W Lankester ◽  
Shane P Mahoney
Keyword(s):  
Rangifer Tarandus ◽  
Climatic Factors ◽  
Rangifer Tarandus Caribou ◽  
Intermediate Hosts ◽  
Parasite Abundance ◽  
Annual Minimum Temperature ◽  
Transmission Period ◽  
Summer Temperatures ◽  
Elaphostrongylus Rangiferi ◽  
Dual Infections

Elaphostrongylus rangiferi was introduced to caribou (Rangifer tarandus caribou) of Newfoundland by infected reindeer (R. t. tarandus) from Norway and has caused at least two epizootics of cerebrospinal elaphostrongylosis (CSE), a debilitating neurologic disease. In an attempt to understand the conditions necessary for such outbreaks, we examined the effects of herd density and climatic factors on parasite abundance. The abundance of E. rangiferi was represented by counts of first-stage larvae in feces collected from young caribou (calves and yearlings) in 7 distinct caribou herds in Newfoundland. Abundance of E. rangiferi was highest in February and in the Avalon (632 ± 14 (mean ± SE)) and St. Anthony (526 ± 145) herds, the 2 herds in which CSE was most frequently reported. Mean abundance in February samples from young animals correlated positively with mean annual minimum temperature (rS = 0.829, df = 6, P = 0.04) and the number of days per year above 0°C (rS = 0.812, df = 6, P = 0.05) and negatively with mean summer temperatures (rS = –0.830, df = 6, P = 0.04). Results suggest that abundance of E. rangiferi and the likelihood of cases of CSE are increased by moderate summer temperatures suitable for the activity and infection of gastropod intermediate hosts and by mild winters with little snow that extend the transmission period. Abundance of larvae was not correlated with herd density. Animals in all 7 herds also had the muscle worm Parelaphostrongylus andersoni, a related nematode with similar dorsal-spined larvae. In 2 additional herds (Cape Shore and Bay de Verde), P. andersoni occurred alone and larvae were passed only by young caribou. In herds with dual infections, numbers of P. andersoni larvae were depressed, declined more quickly in young animals, and were considered to be present in only low numbers in February samples used for E. rangiferi analysis. Upon initial infection, young caribou develop a resistance to E. rangiferi that prevents or reduces reinfection later in life. This was demonstrated by examining the brains of caribou for recently acquired worms, which must develop there for up to 90 days before continuing their tissue migration into the skeletal muscles. Recent infections were detected in only calves and yearlings in all herds with E. rangiferi except the Avalon herd, where developing worms were also found on the brains of older caribou. The infection of older animals in the Avalon herd may reflect a lower immunocompetence of a naive herd that has only recently been exposed to E. rangiferi.

scholarly journals Protostrongylid nematodes in caribou (Rangifer tarandus caribou) and moose (Alces alces) of Newfoundland

Rangifer ◽  
1998 ◽  
Vol 18 (5) ◽  
pp. 73 ◽  
Author(s):  
Murray W. Lankester ◽  
David Fong
Keyword(s):  
Neurological Disease ◽  
Rangifer Tarandus ◽  
Alces Alces ◽  
Neurologic Disease ◽  
Rangifer Tarandus Caribou ◽  
Intermediate Hosts ◽  
Third Stage ◽  
Avalon Peninsula ◽  
Terrestrial Gastropod

Two species of protostrongylid nematodes with dorsal-spined, first-stage larvae, are present in caribou and moose of Newfoundland. Elaphostrongyius rangiferi Mitskevich, 1958, a parasite introduced from Scandinavia, causes periodic epizootics of a severe neurological disease in caribou. Sick animals exhibiting signs of cerebrospinal elaphostrongylosis (CSE) were particularly noticeable in central Newfoundland each winter between 1981 and 1985. Those collected for examinarion were mostly male calves. The disease again became prominent in caribou on the Avalon Peninsula in the winters of 1996 and 1997; it may have spread to that isolated part of the province as recently as 1990. E. rangiferi was also found in moose but no cases of neurologic disease have been reported in this host. Parelapbostrongylus andersoni Prestwood, 1972, was found in caribou, both in central Newfoundland and on the Avalon Peninsula. Moose may also be infected. Of 1407 terrestrial gastropod intermediate hosts examined, 9 (0.6%) contained infective, third-stage, protostrongylid larvae resembling those of E. rangiferi and P. andersoni which are indistinguishable. The small dark slug, Deroceras laeve, dominated gastropod collections and was the only species infected.

scholarly journals Wolf predation in the Burwash caribou herd, southwest Yukon

Rangifer ◽  
1986 ◽  
Vol 6 (2) ◽  
pp. 137 ◽  
Author(s):  
David A. Gauthier ◽  
John B. Theberge
Keyword(s):  
Rangifer Tarandus ◽  
Climatic Factors ◽  
Mortality Factor ◽  
Rangifer Tarandus Caribou ◽  
Limited Data ◽  
Mortality Factors ◽  
Wolf Predation ◽  
Calf Mortality ◽  
Annual Mortality

The role of wolf predation as a proximate mortality factor influencing caribou herd growth was assessed in the Burwash herd (400 animals) in the southwest Yukon between 1980 - 1982. Ten to 14 wolves in two packs preyed primarily on caribou (Rangifer tarandus caribou) and moose (Alces alces) with disproportionate consumption of caribou (relative to available biomass) in the rut and winter periods. Wolf predation was responsible for 72% of total annual mortality in 1980 - 1981 and 46% in 1981 - 1982. Losses due to human harvest varied between 7 to 13%. Additional limited data on climatic factors and winter forage indicated forage-climate were not major proximate mortality factors in 1980 - 1981, but that early-calving climate may have been a factor in increased calf mortality in 1982.

Pleistocene ungulates from the Bow River gravels at Cochrane, Alberta

1968 ◽  
Vol 5 (6) ◽  
pp. 1467-1488 ◽  
Author(s):  
C. S. Churcher
Keyword(s):  
United States ◽  
Late Pleistocene ◽  
Rangifer Tarandus ◽  
Ovis Canadensis ◽  
Southern United States ◽  
Rangifer Tarandus Caribou ◽  
Cervus Canadensis ◽  
North Bank ◽  
Middle And Late Pleistocene

Five ungulates are reported from gravels comprising the second major terrace above the Bow River's north bank at Cochrane, Alberta. These ungulates are Cervus canadensis (wapiti), Rangifer tarandus (caribou), Ovis canadensis (mountain sheep), Bison occidentalis (extinct western bison), and Equus conversidens (extinct Mexican ass). E. conversidens was previously known from middle and late Pleistocene beds of the southern United States and Mexico and is here reported from the post-Wisconsin Pleistocene of Alberta and possibly Saskatchewan. Radiocarbon analysis of Bison bones from the gravels yielded two dates that averaged 11 065 B.P.

scholarly journals Effect of Climatic Factors on Stem Biomass and Carbon Stock of Larix gmelinii and Betula platyphylla in Daxing’anling Mountain of Inner Mongolia, China

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Dilawar Khan ◽  
Muhammad Atif Muneer ◽  
Zaib-Un- Nisa ◽  
Sher Shah ◽  
Muhammad Amir ◽  
...  
Keyword(s):  
Inner Mongolia ◽  
Negative Impact ◽  
Climatic Factors ◽  
High Temperature Stress ◽  
Climatic Conditions ◽  
Larix Gmelinii ◽  
Maximum Temperature ◽  
Betula Platyphylla ◽  
Stem Biomass ◽  
Annual Minimum Temperature

Climate change has become a global concern for scientists as it is affecting almost every ecosystem. Larix gmelinii and Betula platyphylla are native and dominant forest species in the Daxing’anling Mountains of Inner Mongolia, playing a major role in carbon sequestration of this region. This study was carried out to assess the effect of climate variables including precipitation and temperature on the biomass of Larix gmelinii and Betula platyphylla forests. For this purpose, we used the climate-sensitive stem biomass allometric model for both species separately to find out accurate stem biomass along with climatic factors from 1950 to 2016. A total of 66 random plots were taken to attain the data from this study area. Larix gmelinii and Betula platyphylla stem biomass have a strong correlation with annual precipitation (R2 = 0.86, R2 = 0.71, R2 = 0.79, and R2 = 0.59) and maximum temperature (R2 = 0.76, R2 = 0.64, R2 = 0.67, and R2 = 0.52). However, annual minimum temperature (R2 = 0.58, R2 = 0.43, R2 = 0.55, and R2 = 0.46) and annual mean temperature (R2 = 0.40, R2 = 0.22, R2 = 0.36, and R2 = 0.19) have a relatively negative impact on tree biomass. Therefore, we suggest that both species have a very strong adaptive nature with climatic variation and hence can survive under drought and high-temperature stress climatic conditions.

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

Rangifer ◽  
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.

scholarly journals Harvest strategies for the elimination of low prevalence wildlife diseases

2021 ◽  
Vol 8 (3) ◽  
Author(s):  
Atle Mysterud ◽  
Hildegunn Viljugrein ◽  
Christer M. Rolandsen ◽  
Aniruddha V. Belsare
Keyword(s):  
Disease Surveillance ◽  
Rangifer Tarandus ◽  
Time Window ◽  
Disease Prevalence ◽  
Management Approach ◽  
Wildlife Diseases ◽  
Demographic Groups ◽  
Short Time Window ◽  
Transmission Period ◽  
Low Prevalence

The intensive harvesting of hosts is often the only practicable strategy for controlling emerging wildlife diseases. Several harvesting approaches have been explored theoretically with the objective of lowering transmission rates, decreasing the transmission period or specifically targeting spatial disease clusters or high-risk demographic groups. Here, we present a novel model-based approach to evaluate alternative harvest regimes, in terms of demographic composition and rates, intended to increase the probability to remove all infected individuals in the population during the early phase of an outbreak. We tested the utility of the method for the elimination of chronic wasting disease based on empirical data for reindeer ( Rangifer tarandus ) in Norway, in populations with (Nordfjella) and without (Hardangervidda) knowledge about exact disease prevalence and population abundance. Low and medium harvest intensities were unsuccessful in eliminating the disease, even at low prevalence. High-intensity harvesting had a high likelihood of eliminating the disease, but probability was strongly influenced by the disease prevalence. We suggest that the uncertainty about disease prevalence can be mitigated by using an adaptive management approach: forecast from models after each harvest season with updated data, derive prevalence estimates and forecast further harvesting. We identified the problems arising from disease surveillance with large fluctuations in harvesting pressure and hence sample sizes. The elimination method may be suitable for pathogens that cause long-lasting infections and with slow epidemic growth, but the method should only be attempted if there is a low risk of reinfection, either by a new disease introduction event (e.g. dispersing hosts) or due to environmental reservoirs. Our simulations highlighted the short time window when such a strategy is likely to be successful before approaching near complete eradication of the population.

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