Svein D. Mathiesen

Illustrating the coupled human- environment system for vulnerability analysis: Three case studies

The vulnerability framework of the Research and Assessment Systems for Sustainability Program explicitly recognizes the coupled human–environment system and accounts for interactions in the coupling affecting the systems responses to hazards and its vulnerability. This paper illustrates the usefulness of the vulnerability framework through three case studies: the tropical southern Yucatán, the arid Yaqui Valley of northwest Mexico, and the pan-Arctic. Together, these examples illustrate the role of external forces in reshaping the systems in question and their vulnerability to environmental hazards, as well as the different capacities of stakeholders, based on their access to social and biophysical capital, to respond to the changes and hazards. The framework proves useful in directing attention to the interacting parts of the coupled system and helps identify gaps in information and understanding relevant to reducing vulnerability in the systems as a whole.

Molecular Diversity of the Rumen Microbiome of Norwegian Reindeer on Natural Summer Pasture

The molecular diversity of the rumen microbiome was investigated in five semi-domesticated adult female Norwegian reindeer (Rangifer tarandus tarandus) grazing on natural summer pastures on the coast of northern Norway (71.00° N, 25.30° E). Mean population densities (numbers per gram wet weight) of methanogenic archaea, rumen bacteria and ciliate protozoa, estimated using quantitative real-time polymerase chain reaction (PCR), were 3.17 × 109, 5.17 × 1011 and 4.02 × 107, respectively. Molecular diversity of rumen methanogens was revealed using a 16S rRNA gene library (54 clones) constructed using pooled PCR products from the whole rumen contents of the five individual reindeer. Based upon a similarity criterion of <97%, a total of 19 distinct operational taxonomic units (OTUs) were identified, nine of which are potential new species. The 16S rRNA sequences generated from the reindeer rumen exhibited a high degree of sequence similarity to methanogens affiliated with the families Methanobacteriaceae (14 OTUs) and Methanosarcinaceae (one OTU). Four of the OTUs detected belonged to a group of uncultivated archaea previously found in domestic ruminants and thought to be dominant in the rumen together with Methanobrevibacter spp. Denaturing gradient gel electrophoresis profiling of the rumen bacterial 16S rRNA gene and the protozoal 18S rRNA gene indicated a high degree of animal variation, although some bands were common to all individuals. Automated ribosomal intergenic spacer analysis (ARISA) profiling of the ruminal Neocallimastigales population indicated that the reindeer are likely to contain more than one type of anaerobic fungus. The ARISA profile from one animal was distinct from the other four. This is the first molecular investigation of the ruminal methanogenic archaea in reindeer, revealing higher numbers than expected based on methane emission data available. Also, many of the reindeer archaeal 16S rRNA gene sequences were similar to those reported in domesticated ruminants in Australia, Canada, China, New Zealand and Venezuela, supporting previous findings that there seems to be no host type or geographical effect on the methanogenic archaea community structure in ruminants.

Rumen microbial diversity in Svalbard reindeer, with particular emphasis on methanogenic archaea

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.

Food intake, digestibility and rumen fermentation in reindeer fed baled timothy silage in summer and winter

Reindeer calves (Rangifer tarandus tarandus) were used in parallel feeding trials with two different qualities of round-bale timothy silage in September 1992 (summer) and April 1993 (winter) in northern Norway, to determine the effect of season on their food intake and ability to utilize silage of different fibre contents. The silages were prepared from first-cut (FC) and regrowth (RG) timothy. The FC silage contained (on a dry matter (DM) basis) 12.3 % crude protein, 30.4 % cellulose and 6.2% water soluble carbohydrates (WSC), whereas the RG silage contained 14.3 % crude protein, 18.7 % cellulose and 30.0 % WSC. For each trial, six male calves were taken directly from a natural range and divided into two groups of three animals. One group was offered FC silage and one RG silage ad libitum, for 46 days. Mean daily DM food intake (g/kg liveweight) was not significantly different in summer compared to winter (P > 0.05), but significantly higher in the animals fed RG silage compared to the animals fed FC silage (P < 0.0001). The apparent digestibility coefficient of DM was high for both silages both in summer and winter, ranging from 74.4 to 86.6 %. However, the digestibility in winter was significantly higher than in summer (P < 0.002) and the digestibility of RG silage was higher than that of the FC silage (P < 0.009). The ruminal VFA concentration was significantly higher in winter than in summer (P < 0.03) and in the animals fed RG silage (range 55.3-104.9 mM) compared to the animals fed FC silage (range 35.2-61.7 mM) (P < 0.002). In spite of the high digestibility of both the FC and RG silages, the nitrogen balance was significantly higher in the animals in winter compared to summer (P < 0.0001) and in the animals fed RG silage compared to the animals fed FC silage (P < 0.0001). Thus, utilization of grass silage in reindeer appears to be influenced both by season and by plant quality.

Round baled grass silage as food for reindeer in winter

Round baled silage of mixed grasses was tested as emergency food for reindeer in winter. The silage was made of leaf rich regrowth of Phleum pratense, Agrostis tenuis and Poa spp. It contained 33-3% dry matter (DM), and 14.8 % crude protein, 24.5% cellulose and 26.7% hemicellulose on a DM basis. Palatability, food intake, digestion, rumen fermentation, body mass (BM), carcass weight and gastrointestinal (GI) anatomy were investigated. A group of adult female reindeer (n = 38), were taken from natural winter pasture and fed grass silage ad libitum. The majority (78%) of the animals were eating silage after two days and 95% of the animals ate silage after five days. Five reindeer calves were taken from natural winter pasture and fed lichens ad libitum for 14 days after which they were starved for two days before being offered silage adlibitum. The median daily DM food intake was 370 g (range 250-610 g) on the first day increasing to 810 g (range 530-1100 g) at days 16 to 20. Median apparent digestibility coefficient (DC) of DM was 64.3% (range 62.4-66.2%). The median in vitro DM digestibility (IVDMD) of the silage after 72 h of microbial digestion was 68.3 % (range 66.6-71.3 %) (Ws=30, n,=5, n2=4, P<0.01). Median ruminal VFA concentration and pH were 48.2 mM (range 38.4-52.5 mM) and 7.0 (range 6.95-7.17), respectively, in the reindeer calves (n=5). BM initially increased when the reindeer calves were fed silage, but stabilised after 11 days. The increased BM may have been due to an increased recticulo-rumen digesta load, which amounted to 19.6-23.7 % of BM (n=3). The carcass weight of the reindeer calves was 42.6-44.2% of the BM (n=3) after 47 days of silage feeding. The results indicate that although the round bale silage of mixed grasses of medium quality was highly palatable to reindeer it was apparantly of only limited value as an emergency food for the reindeer calves, as indicated by low DC of DM and low ruminal VFA concentration.

Effects of seasonal changes in food quality and food intake on the transport of sodium and butyrate across ruminal epithelium of reindeer

Transport of 22Na and 14C-butyrate across the ruminal epithelium of captive reindeer fed a concentrate diet in summer (n=5) and in winter (n=5) and from free-ranging reindeer taken from summer (n=3) and winter pasture (n=5) was measured in vitro in Ussing chambers. Significant amounts of both Na+ and butyrate were transported across the isolated epithelium without any external driving force. The ruminal transport of Na+ and butyrate were interacting, as evidenced by both the observed amiloride-induced reduction of net butyrate-transport and by the positive correlation between net transport of butyrate and Na+. Amiloride also reduced the net transport of Na+ without significantly affecting the short-circuit current, indicating the presence of an apical Na+/H+ exchanger in the ruminal epithelium of reindeer. The captive reindeer increased the dry matter intake of a constant quality concentrate from winter to summer, but this neither affected their ruminal transport capacity nor their ruminal surface enlargement factor (SEF). Free-ranging reindeer increased their ruminal transport capacity for Na+ and butyrate from summer to winter but simultaneously reduced their ruminal SEF. The present data indicate that this food-induced increase in transport capacity was attributed to changes in the nutrient composition of the diet.

Food intake of reindeer in winter

Management of semi-domesticated reindeer ( Rangifer tarandus tarandus ) in the northern regions have historically focused on reindeer–vegetation interactions, while few data on the food intake of these animals exist. Dry matter intake (DMI) was therefore estimated successively during winter in reindeer calves fed (i) ad libitum pelleted reindeer feed (RF-80; n =6), (ii) fed ad libitum mixed lichens ( n =6) and (iii) in free-ranging reindeer calves ( n =3) on natural winter pasture (March/April; 69 °N). Faecal output, determined with faeces collection bags, was 24±4, 6±3 and 22±3 g DM/day/kg BM 0·75 in reindeer fed RF-80, mixed lichens and on winter pasture, respectively. Actual DMI of reindeer in captivity fed RF-80 and mixed lichens was 70±10 g DM/day/kg BM 0·75 and 27±8 g DM/day/kg BM 0·75 , respectively. The DMI of the captive reindeer calves was accurately estimated on both diets on the basis of the digestibility of their diet and their faecal output. Using the same method, the DMI of free-ranging reindeer calves on natural winter pastures in northern Norway was estimated to be 34–61 g DM/day/kg BM 0·75 . The present study discusses factors that influence the food intake of reindeer in winter with emphasis on the seasonal regulation of appetite and DMI in these Arctic ruminants.

Food and snow intake, body mass and rumen function in reindeer fed lichen and subsequently starved for 4 days

Food and snow intake, body mass, rumen fluid volume, rumen fluid turnover time and ruminal dry matter content were examined in four female rumen fistulated reindeer which were first fed lichen ad libitum in 14 days and then starved for 4 days in March. When the animals were eating lichen median daily dry matter food intake was 15.7 g/kg (range 12.2-19.9 g/kg), while median daily snow intake only amounted to 0.6 g/kg (range 0-3.3 g/kg). The median body mass decreased from 67.5 kg (range 62.5-69.5 kg) to 63.5 kg (range 60.5-68.5 kg) during this period, and dropped further to 62.5 kg (range 57.5-66.0 kg) after four days of starvation. Rumen fluid volume and fluid turnover time were fairly constant in individual animals, but varied between animals fed lichen ad libitum. Neither of these parameters changed significantly (P>0.05), but ruminal dry matter decreased, while snow intake rose conspicuously in reponse to starvation. Thus, aside from the latter, which mitigate the reduction of total rumen volume, we have failed to expose any special adaptions aimed at the maintenance of ruminal integrity in starving reindeer.

Fatal inanition in reindeer (Rangifer tarandus tarandus): Pathological findings in completely emaciated carcasses

BackgroundIn a project to determine the causes of winter mortality in reindeer in Finnmark County, northern Norway, the most frequent diagnosis turned out to be complete emaciation, despite several of the reindeer having been given silage for up to 4 weeks before they died. The present paper describes autopsy results and other findings in these animals.MethodsAutopsies were made of 32 reindeer carcasses, and 28 of these were diagnosed as completely emaciated based on lack of visible fat and serous atrophy of subepicardial and bone marrow fat. Other investigations of the carcasses included histology, bacteriology, parasitology (counting of macro parasites and faecal egg counting), analysis of vitamin E and selenium in liver, chemical and botanical analysis of rumen content, analysis of lipid content in femur bone marrow and estimation of muscle atrophy by use of a muscle index.ResultsMain findings were: Low carcass weight, severe muscle atrophy, hemosiderosis in liver and spleen, subcutaneous oedema (18%) and effusions to body cavities (18%). Two types of lipofuscin granula were identified in the liver: One type occurred in liver endothelial cells of all carcasses, while the other type occurred in hepatocytes, and prevailed in adult animals. Abomasal haemorrhages, consistent with previously described stress lesions, was present in 68% of the carcasses. Diarrhoea occurred in 2 cases, and loose faecal consistency was associated with silage feeding. Rumen content was low in crude protein. Grass dominated rumen content in silage-fed carcasses, while reindeer on natural pastures had mainly woody plants, mosses and litter in rumen. Stem dominated the grass fraction in rumens with high grass content, indicating ruminal indigestion as a cause of emaciation in silage fed animals. Some cases had heavy infestation of parasites such as warble fly larvae (Hypoderma tarandi), throat bot larvae (Cephenemyiae trompe) and lung nematodes.ConclusionLack of appropriate amounts and/or appropriate quality of feed has been the main cause of emaciation, though heavy infestation of parasites may have contributed to the emaciation in some cases.

Metabolic rate and plasma T3 in ad lib. fed and starved muskoxen

Resting metabolic rate (RMR) in two 12 yrs., semidomesticated, female muskoxen was 0.86 ± 0.10 W • kg-1 in winter, and 1.74 ± 0.27 W • kg-1 in summer, (p<0.001). After 6 days of starvation RMR was down to 0.62 + 0.07 W • kg-1 and 0.77 ± 0.03 W • kg-1 (p<0.001) in winter and summer, respectively. RMR during starvation in winter was 19% below predicted RMR for animals of equal body mass. Standing RMR was significantly higher (p<0.01) than lying RMR. Winter plasma levels of T3 in both animals were 1-1 nmol • l-1 when food was freely available, and 1.4 nmol • l-1 after 6 days of starvation. Plasma concentration of T3 in another 8 free ranging semi-domesticated, female muskoxen aged 12 yrs. in March was 0.64 ± 0.20 nmol • l-1. Corrseponding value in August was 1.00 ± 0.10 nmol • l-1, being significantly higher (p<0.01) than the winter value.