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1.
Predation of Svalbard reindeer by polar bears   总被引:2,自引:0,他引:2  
Polar bears (Ursus maritimus) are believed to be obligate predators on marine mammals, and particularly, on two species of seals. This paper reports on observations of polar bears preying (n=7) and scavenging (n=6) on Svalbard reindeer (Rangifer tarandus platyrhyncus). Similar to their closest evolutionary ancestor, the brown bear (U. arctos), polar bears are opportunistic and will prey on ungulates. Reindeer are likely of minor importance to the foraging ecology of polar bears in Svalbard, but the observations suggest behavioural plasticity in response to a novel prey item. Accepted: 26 March 2000  相似文献   

2.
Several of the most important reindeer forage plants in Svalbard were analysed for content of minerals (Na, K, P, Ca, Mg, S, Cl, Fe, Cu, Mn, Zn, Mo and Co) and for content of ash, crude protein, crude fiber, ether extracts and nitrogen free extracts. Some forage plants were also examined in in vitro digestibility trials. The results were compared with results from similar analyses of alpine mountain plants from southern Norway. Also freshly voided fecal samples were analysed for the same components as the forage plants.
The Svalbard vegetation had a higher content of Na, Ca, Mg, Cl, Fe and Co, than similar plants from Southern Norway. The content of other elements examined seemed to be more equal in Norway and on Svalbard. Within the Svalbard area plants growing in limestone areas had the highest content of calcium and magnesium. Also plants growing on manured soil below bird cliffs appeared to have high nutritional value. It is furthermore concluded that the closeness to the sea as well as the occurrence of several plants with high mineral content, gave the Svalbard reindeer the possibility to further improve their mineral balance compared with continental reindeer. Also the dietary shift from lichens as a major dietary component in Norway, to mosses on Svalbard, may increase mineral intake, but may also have an inferior effect on digestibility.
Although balance experiments and carcass analyses of minerals in Svalbard reindeer are missing, it is concluded that Svalbard reindeer apparently had adequate intake of most mineral elements. In spite of low standing biomass of reindeer forage plants, the quality of the vegetation seemed to compare favourably with continental reindeer pasture.  相似文献   

3.
beta R fibres (type I) constitute less than 10% of the semimembranosus and longissimus dorsi muscles and about twice as much of the gluteobiceps and flexor hallucis. Except for longissimus dorsi, 50% or more consist of alpha W (type IIB) fibres--in semimembranous, as much as 70%. Despite the comparatively large content of alpha W fibres, both the oxidative capacity and the capacity to metabolize fatty acids is high. Furthermore, unexpectedly small differences in oxidative capacity between the three fibre types beta R, alpha R and alpha W (I, IIA and IIB) are revealed by histochemical staining. These results indicate a tendency to bring the three fibre types closer together as regards metabolic activities, as an adaptation to the relatively tranquil life of this animal. However, the large content of alpha W fibres does not accord well with this way of life, as they guarantee quick movements. The comparatively high oxidative capacity of the alpha W fibres in the Svalbard reindeer and the fact that during starvation it is primarily alpha W fibres that contribute to the energy supply by protein degradation may nevertheless account for their abundant occurrence.  相似文献   

4.
5.
Ruminants depend on efficient physical degradation of forage through chewing to increase the surface area of the food particles presented to the microflora. Fossil evidence suggests that increased molar height is an adaptation for wear tolerance in dry ecosystems with sparse vegetation, but no study has shown selection pressure for hypsodonty in contemporary ruminants. We explored the relationships between particle size in rumen, tooth wear (scanned molar occlusal topography), age and body mass of female Svalbard reindeer living in an arctic desert at 78 degrees latitude on Svalbard. We predicted that (H1) if the rumen particle size is determined mainly by constraints due to tooth wear, and if tooth wear is mainly a function of age, average particle size in rumen should increase with age. From allometric relations it is known that larger individuals can survive on a lower-quality diet, we therefore predicted (H2) larger particle sizes with increases in (ln) body mass, irrespective of age and wear. Lastly, if there is a trade-off between growth and tooth wear in dry ecosystems (a selection pressure for hypsodonty), we predicted (H3) that teeth of heavier animals should be more worn than those of lighter animals of the same age. The proportion of small particles (<1.0 mm) decreased rapidly with increasing age (consistent with H1). Heavier females within an age class had more worn teeth (consistent with H3) than lighter ones. A close-to-isometric relationship between particle size and body mass suggested that heavier animals partly compensated for reduced tooth efficiency by chewing more. We provide the first evidence of a trade-off between fast early growth and wear (a somatic cost) of a senescence-related trait--the structure and height of the molar--in a wild ruminant inhabiting an arctic desert where selection pressure for increased tooth height is expected. This suggests that foraging conditions are more extreme than the environment in which the species originally evolved.  相似文献   

6.
Ruminal methanogens, bacteria and ciliate protozoa of Svalbard reindeer grazing natural pastures in October (late fall) and April (late winter) were investigated using molecular-based approaches. The appetite of the Svalbard reindeer peaks in August (summer) and is at its lowest in March (winter). Microbial numbers, quantified by real-time PCR, did not change significantly between October and April, when food intakes are at similar levels, although the numbers of methanogens tended to be higher in October ( P =0.074), and ciliate numbers tended to be higher in April ( P= 0.055). Similarly, no change was detected in the bacterial and protozoal population composition by rRNA gene-based denaturing gradient gel electrophoresis analysis. Dominant methanogens were identified using a 16S rRNA gene library (97 clones) prepared from pooled PCR products from reindeer on October pasture ( n =5). Eleven of the 22 distinct operational taxonomic units (OTUs) generated exhibited a high degree of sequence similarity to methanogens affiliated with Methanobacteriales (eight OTUs), Methanomicrobiales (one OTU) and Methanosarcinales (two OTUs). The remaining 11 OTUs (53% of the clones) were associated with a cluster of uncultivated ruminal archaea. This study has provided important insights into the rumen microbiome of a high-arctic herbivorous animal living under harsh nutritional conditions, and evidence suggesting that host type affects the population size of ruminal methanogens.  相似文献   

7.
Lignocellulosic biomass remains a largely untapped source of renewable energy predominantly due to its recalcitrance and an incomplete understanding of how this is overcome in nature. We present here a compositional and comparative analysis of metagenomic data pertaining to a natural biomass-converting ecosystem adapted to austere arctic nutritional conditions, namely the rumen microbiome of Svalbard reindeer (Rangifer tarandus platyrhynchus). Community analysis showed that deeply-branched cellulolytic lineages affiliated to the Bacteroidetes and Firmicutes are dominant, whilst sequence binning methods facilitated the assemblage of metagenomic sequence for a dominant and novel Bacteroidales clade (SRM-1). Analysis of unassembled metagenomic sequence as well as metabolic reconstruction of SRM-1 revealed the presence of multiple polysaccharide utilization loci-like systems (PULs) as well as members of more than 20 glycoside hydrolase and other carbohydrate-active enzyme families targeting various polysaccharides including cellulose, xylan and pectin. Functional screening of cloned metagenome fragments revealed high cellulolytic activity and an abundance of PULs that are rich in endoglucanases (GH5) but devoid of other common enzymes thought to be involved in cellulose degradation. Combining these results with known and partly re-evaluated metagenomic data strongly indicates that much like the human distal gut, the digestive system of herbivores harbours high numbers of deeply branched and as-yet uncultured members of the Bacteroidetes that depend on PUL-like systems for plant biomass degradation.  相似文献   

8.
The dominant cecal bacteria in the high-arctic Svalbard reindeer were characterized, their population densities were estimated, and cecal pH was determined in summer, when food quality and availability is good, and in winter, when it is very poor. In summer the total culturable viable bacterial population was (8.9 +/- 5.3) X 10(8) cells ml-1, whereas in winter it was (1.5 +/- 0.7) X 10(8) cells ml-1, representing a decrease to 17% of the summer population density. Of the dominant species of cultured bacteria, Butyrivibrio fibrisolvens represented 23% in summer and 18% in winter. Streptococcus bovis represented 17% in summer and 5% in winter. Bacteroides ruminicola represented 10% in summer and 26% in winter. In summer and winter, respectively, the proportion of the viable population showing the following activities was as follows: fiber digestion, 36 and 48%; cellulolysis, 10 and 6%; xylanolysis, 33 and 48%; and starch utilization, 77 and 71%. The most abundant cellulolytic species in summer was Butyrivibrio fibrisolvens, representing 62% of the total cellulolytic population, and in winter it was Ruminococcus albus, representing 80% of the total cellulolytic population. The most abundant xylanolytic species in summer was Butyrivibrio fibrisolvens, and in winter it was Bacteroides ruminicola, representing 59 and 54% of the xylanolytic isolates in summer and winter, respectively. The cecal bacterial of the Svalbard reindeer have the ability to digest starch and the major structural carbohydrates of the diet that are not digested in the rumen. The cecum in these animals has the potential to contribute very substantially to the digestion of the available plant material in both summer and winter.  相似文献   

9.
The dominant cecal bacteria in the high-arctic Svalbard reindeer were characterized, their population densities were estimated, and cecal pH was determined in summer, when food quality and availability is good, and in winter, when it is very poor. In summer the total culturable viable bacterial population was (8.9 +/- 5.3) X 10(8) cells ml-1, whereas in winter it was (1.5 +/- 0.7) X 10(8) cells ml-1, representing a decrease to 17% of the summer population density. Of the dominant species of cultured bacteria, Butyrivibrio fibrisolvens represented 23% in summer and 18% in winter. Streptococcus bovis represented 17% in summer and 5% in winter. Bacteroides ruminicola represented 10% in summer and 26% in winter. In summer and winter, respectively, the proportion of the viable population showing the following activities was as follows: fiber digestion, 36 and 48%; cellulolysis, 10 and 6%; xylanolysis, 33 and 48%; and starch utilization, 77 and 71%. The most abundant cellulolytic species in summer was Butyrivibrio fibrisolvens, representing 62% of the total cellulolytic population, and in winter it was Ruminococcus albus, representing 80% of the total cellulolytic population. The most abundant xylanolytic species in summer was Butyrivibrio fibrisolvens, and in winter it was Bacteroides ruminicola, representing 59 and 54% of the xylanolytic isolates in summer and winter, respectively. The cecal bacterial of the Svalbard reindeer have the ability to digest starch and the major structural carbohydrates of the diet that are not digested in the rumen. The cecum in these animals has the potential to contribute very substantially to the digestion of the available plant material in both summer and winter.  相似文献   

10.
The dominant rumen bacteria in high-arctic Svalbard reindeer were characterized, their population densities were estimated, and ruminal pH was determined in summer, when food quality and availability are good, and in winter, when they are poor. In summer the total cultured viable population density was (2.09 +/- 1.26) X 10(10) cells ml-1, whereas in winter it was (0.36 +/- 0.29) X 10(10) cells ml-1, representing a decrease to 17% of the summer population density. On culture, Butyrivibrio fibrisolvens represented 22% of the bacterial population in summer and 30% in winter. Streptococcus bovis represented 17% of the bacterial population in summer but only 4% in winter. Methanogenic bacteria were present at 10(4) cells ml-1 in summer and 10(7) cells ml-1 in winter. In summer and winter, respectively, the proportions of the viable population showing the following activities were as follows: starch utilization, 68 and 63%; fiber digestion, 31 and 74%; cellulolysis, 15 and 35%; xylanolysis, 30 and 58%; proteolysis, 51 and 28%; ureolysis, 40 and 54%; and lactate utilization, 13 and 4%. The principal cellulolytic bacterium was B. fibrisolvens, which represented 66 and 52% of the cellulolytic population in summer and winter, respectively. The results indicate that the microflora of the rumen of Svalbard reindeer is highly effective in fiber digestion and nitrogen metabolism, allowing the animals to survive under the austere nutritional conditions typical of their high-arctic habitat.  相似文献   

11.
The dominant rumen bacteria in high-arctic Svalbard reindeer were characterized, their population densities were estimated, and ruminal pH was determined in summer, when food quality and availability are good, and in winter, when they are poor. In summer the total cultured viable population density was (2.09 +/- 1.26) X 10(10) cells ml-1, whereas in winter it was (0.36 +/- 0.29) X 10(10) cells ml-1, representing a decrease to 17% of the summer population density. On culture, Butyrivibrio fibrisolvens represented 22% of the bacterial population in summer and 30% in winter. Streptococcus bovis represented 17% of the bacterial population in summer but only 4% in winter. Methanogenic bacteria were present at 10(4) cells ml-1 in summer and 10(7) cells ml-1 in winter. In summer and winter, respectively, the proportions of the viable population showing the following activities were as follows: starch utilization, 68 and 63%; fiber digestion, 31 and 74%; cellulolysis, 15 and 35%; xylanolysis, 30 and 58%; proteolysis, 51 and 28%; ureolysis, 40 and 54%; and lactate utilization, 13 and 4%. The principal cellulolytic bacterium was B. fibrisolvens, which represented 66 and 52% of the cellulolytic population in summer and winter, respectively. The results indicate that the microflora of the rumen of Svalbard reindeer is highly effective in fiber digestion and nitrogen metabolism, allowing the animals to survive under the austere nutritional conditions typical of their high-arctic habitat.  相似文献   

12.
Alendal, E., de Bie, S. and van Wieren, S. E. 1979. Size and composition of the wild reindeer Rangifer tarandus platyrhynchus population in the Southeast Svalbard Nature Reserve. Holarct. Ecol. 2: 101-107. In the summer of 1977 we studied the reindeer population on the islands Barentsøya and Edgeøya in the eastern part of the Svalbard archipelago. A total of 1374 reindeer were observed: 326 animals in the western parts of Barentsøya and 1048 animals on Edgeøya. Considering those parts of Edgeøya which were not visited, the total number of reindeer on Edgeøya was estimated at 1300 animals. The total number of reindeer was lower than in previous years. The decline probably was due to severe winter conditions in 1975/1976 and 1976/1977 confirmed by the fact that many carcasses and few yearlings were observed. Nearly all reindeer occurred on the coastal plains and in the valleys. These areas have the relatively richest vegetation. The average recruitment of the total population (counted) was 15.9%. The adult sex ratio was in favour of females: 59% females versus 41% males. There were differences both in the recruitment and in the adult sex ratio between three distinct areas on Edgeøya and between two on Barentsøya. These differences may be due to dissimilarities in food quality and feeding conditions caused by climate, and by small exchange of reindeer between the areas. The high frequency of shed male antlers on Frankenhalvøya and Talaveraflya, north and south coast of Barentsøya respectively, indicates that these areas belong to the wintering grounds of reindeer on this island. Concentrations of shed female antlers on Barentsøya were less pronounced. The highest frequency was in the areas Sjodalen and Kvistdalen-Talaveraflya in the northwest and south respectively. Females may use these areas as late wintering grounds and possibly as calving areas. The average group size was 2.2 and the aggregation index 3.1. Seventytwo per cent of all groups, containing 48% of all reindeer, fell into group size 1 and 2. Males mostly were observed alone or together with one other animal. Females with calves most frequently occurred in groups of 2 and 4 animals.  相似文献   

13.
A polymerase chain reaction (PCR) assay to identify two common abomasal nematodes Marshallagia marshalli and Ostertagia gruehneri of Svalbard reindeer was developed. Species-specific PCR primers were designed from internal transcribed spacer (ITS)-2 sequences of rDNA and validated using morphologically identified adult male and female nematodes. Using the species-specific primers, a 110 bp fragment was amplified from M. marshalli and its minor morph Marshallagia occidentalis and a 149 bp fragment was amplified from Ostertagia gruehneri and its minor morph Ostertagia arctica. No PCR products were amplified from the third rare species, Teladorsagia circumcincta, or DNA from the reindeer host. The assay provides a useful tool to estimate species composition for both sexes in this nematode community.  相似文献   

14.
DNA sequences of ITS-1 and ITS-2 of rDNA were determined for 16 individual adult males each of Ostertagia gruehneri and Ostertagia arctica from Svalbard reindeer (Rangifer tarandus platyrhynchus) and Eurasian tundra reindeer (R. t. tarandus). Each ITS was virtually identical in O. gruehneri and O. arctica and the three mixed bases detected were shared by both species. Our results strongly suggest that O. gruehneri and O. arctica are dimorphic males of the same species.  相似文献   

15.
Variation in plasma urea and creatinine concentration and plasma urea:creatinine ratio (U:C) were studied in semidomestic free-ranging reindeer (Rangifer tarandus tarandus) on the Norwegian mainland, in wild Svalbard reindeer (Rangifer tarandus platyrhynchus), and in captive reindeer maintained either on a lichen-based diet or a protein-rich concentrate to investigate whether these parameters could be used as indicators of the nutritional status of reindeer. In the mainland animals, plasma creatinine concentration was high in winter and early spring and decreased by two-thirds toward the summer. The overall range in mean plasma creatinine concentration (+/-SE) was from 90+/-1.26 to 280+/-2.88 micromol/L. Mean plasma urea concentration (+/-SE) varied from 2.46+/-0.10 in winter up to 17.44+/-0.29 mmol/L in summer and autumn. Month of sampling explained 65% and 90% of the variation in plasma urea and creatinine concentrations, respectively, indicating that seasonality in the diet had the greatest influence on these parameters. Reindeer given lichens as the only feed showed an increase in plasma creatinine and a decrease in plasma urea concentration. Food restriction caused a temporary elevation in urea level but had no significant effect on plasma creatinine concentration. The slight effect of energy intake on urea and creatinine levels was supported by the fact that severe undernutrition in the Svalbard reindeer population had only a small effect on plasma urea and creatinine levels. Protein-rich pellet feed increased plasma urea from around 3 mmol/L to above 10 mmol/L and reduced creatinine concentrations to less than 100 micromol/L, suggesting that the protein content of forage is an important determinant of these blood parameters. Mean U:C ratio (+/-SE) in plasma varied from 8.9+/-0.28 to 120.8+/-1.88. Ratios above 20 appeared when protein intake was low and energy intake was restricted or when protein intake was high. Low ratios occurred when protein intake was low but energy intake adequate. Plasma urea and creatinine concentrations and the U:C ratio showed complex dynamics that were affected by both season and the protein and feed intake. We conclude that they appear to be difficult to interpret as single measures of nutritional status of reindeer.  相似文献   

16.
Experimental trichinellosis in reindeer   总被引:3,自引:0,他引:3  
Six female reindeer calves were inoculated intraruminally with various doses of Trichinella muscle larvae. Four calves were inoculated with T. nativa, receiving 15,000 (n = 1), 5,000 (1), and 2,500 (2) larvae each. Two calves were inoculated with 5,000 T. spiralis larvae each. Blood samples were collected twice per week for total white blood cell (WBC) and differential counts and for serology using enzyme-linked immunosorbent assay (ELISA) based on T. spiralis excretory-secretory antigen. On day 56, the calves were slaughtered and muscle samples were examined according to the standard digestion method for Trichinella larvae. Blood samples were also collected twice a week from 4 uninoculated, but otherwise similar, reindeer calves corralled separately. Both the total WBC and eosinophil counts of the inoculated animals were, on average, higher during the experimental period. All the inoculated calves seroconverted, showing an increase in the optical density (OD) in the ELISA starting between day 23 and day 27 postinoculation. Very few muscle larvae (<0.08 larvae/g [lpg]) were to be found from the animals inoculated with T. nativa, but about 4 and 6 lpg were recovered from the masseter muscles of those inoculated with T. spiralis.  相似文献   

17.
18.
Septicemic listeriosis is described in a 2-day-old reindeer calf (Rangifer tarandus tarandus) from a local zoo. The gross and microscopic lesions were typical of disease caused by bacterial septicemia. Major lesions included necrosis of the liver, lung, adrenal gland, spleen, and lymph node. The diagnosis was suspected by special histopathological stains and confirmed by isolation of Listeria monocytogenes from multiple organs. This is the first report of listeriosis in a reindeer.  相似文献   

19.
Wild reindeer foraging-niche organization   总被引:7,自引:0,他引:7  
Terje Skogland 《Ecography》1984,7(4):345-379
Part 1: Diet selection was studied on free-ranging reindeer fitted with an esophageal fistula (EF) and by analysis of rumen samples from reindeer shot in the field. Plant density was assessed from quadrats on field plots. Three measures of palatability were used, the nitrogen, fiber, and total non structural carbohydrate (TNC) contents of samples from clipped vegetation. As lichen density decreased the EK reindeer included progressively more vascular litter and pieces of winter dormant species in their diet. Diets with highest TNC and N/F and the lowest fiber, providing the most readily digestible diets, were selected. The combined density-quality criterion gave the best prediction of their diets. In summer, forbs, and to some extent grasses and dwarf shrubs, were selected. Plants of highest density and in an early growth phase gave the best prediction of summer diets. In winter the variety of vascular plants utilized increased with increasing herd size and decreasing density of lichens in the vegetation. The width of diets was a function of diversity of available plants. It is suggested that dietary selection by reindeer has been a three stage process: evolution of a gastro-intestinal system capable of digesting lichens containing secondary compounds, behavioural tracking of the plant production pulse, and diet width scaling according to density-quality of all potential foods. Part 2: Wild reindeer closely followed the wave of vascular plant production in spring and summer with a significant correlation being found between the daily foraging time per habitat type and the highest concentration of green phytomass. Snow-bed meadows were the most consistently selected vegetation type by the four herds studied, viz. Hardangervidda, Snøhetta, Prudhoe Bay, and Svalbard, during the summer. Habitat niche-breadths were narrow during the winter, largely due to the limitation of access to the food supply by the snow-cover, broadened as the landscape became clear of snow, narrowed again with the initiation of plant growth and broadened once more as the wave of plant production reached all habitat types. At high levels of food resources the alpine herd (Hardangervidda) narrowed the feeding niche breadth (or adopted a selective feeding strategy) as the habitat niche breadth increased. The high arctic herd (Svalbard) living in the least productive environment, at the same time of year adopted a generalist feeding strategy as their habitat niche breadth expanded. Part 3: In this part the temporal organization of a low-alpine herd of reindeer (Hardangervidda) is described, and subsequently compared with those of two arctic herds. Their foraging efficiencies under different degrees of food availability were analysed, in order to test the hypothesis that food intake changes in response to the prevailing state of the food resources. The number of daily feeding bouts increased from 2 to 6 as the diet changed from the winter to the summer pasturage. Strong winds in winter and insect harassment in summer severely depressed the daily time spent foraging. When these environmental factors were accounted for no significant inter-seasonal differences in daily foraging time of the low alpine herd were found; on average 50% of each day was spent grazing, of which 78% of the time was spent on actual ingestion (feeding rate). The feeding rate within the active periods varied with the snow-depth, due to the need to dig a food crater in the snow and due to the particular selective feeding strategy adopted. The data from the present and from other studies suggest that the foraging efficiency of wild reindeer, expressed as their daily food intake follows a Holling type II functional response as food availability changes. Part 4: Sheep is the only sympatric ruminant which grazes with the reindeer on alpine pastures in Norway. The inter-specific niche relationships ot the wild reindeer and the domestic sheep in summer were studied on part of the western Hardangervidda. to test the hypothesis of inter-specific competition. Three niche dimensions were meas-ured, diel, habitat utilization, and spatial distribution. The estimates of the degree of overlap obtained suggest that this is relatively high for diet and habitat utilization but low for spatial distribution, which leads to a low degree of foraging interference. Since the intensity of both interspeeific and intra-specific competition depends on the ratio of the herbivore densities to the food resource density, the degree ol overlap in utilization by the two species tell us nothing about the degree of competition. Present numbers of both species on Hardangervidda have a beneficial influence on the vegetation, by opening-up the shrub-layer canopy and thus facilitating the main-tenance of grasses and forbs in the field layer, which has a higher carrying capacity for ruminants. The balance between the beneficial effects and inter-generic competition (if any) deriving from the present-day stocking rales is so tar unknown. Only long-term monitoring of the performance of both populations will shed light on this competitive aspect.  相似文献   

20.
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