Oxygen transport in the blood of arctic mammals: adaptation to local heterothermia

Summary The oxygen binding of whole blood from humans and two arctic mammals, reindeer and muskox, has been studied as a function of carbon dioxide and temperature. All bloods display a marked Bohr effect with Bohr coefficients in the range –0.44––0.73. The Bohr effect is more pronounced at 20°C. The temperature sensitivity of reindeer and muskox blood expressed by the apparent heat of oxygenation, H, is almost three times lower than that of human HbA under the same experimental conditions. This thermodynamic difference gives special benefits to arctic mammals with large heterothermy by safeguarding oxygen unloading at very low ambient temperatures.     

Development of needle retention in Scots pine (Pinus sylvestris) in 1957–1991 in northern and southern Finland

The needle trace method was used to study retrospectively the long-term latitudinal variation in needle retention in Scots pine (Pinus sylvestris L.) in Finland. The mean annual summer needle retention (ANR) along the main stem varied from 3.4 to 6.0 needle sets during the period 1957–1991. The lowest values were observed in southern and the highest in northern Finland. The length of the growing season, expressed as the thermal sum (threshold value +5 °C), was negatively correlated with the mean ANR (r=-0.96). The geographical needle retention pattern (NRP) for the period 1957–1991 showed a clearly increasing trend from 1957 to 1969 (southern Finland) and to 1975 (northern Finland); thereafter, the NRP tended to decrease close to its minimum value recorded in 1991. The general level of the NRP was approximately 5.0 needle sets in northern Finland and 3.5–4.0 needle sets in southern Finland. The NRP, with its 6–12 year cycle for southern Finland, was clearly periodical. Differences in the NRP among the ten stands in southern Finland were small, whereas the said periodicity was missing and the differences were high among the stands in northern Finland. The results indicate that variation in the number of needle sets, viz. defoliation of pines, is a normal phenomenon. The role of net carbon assimilation as a regulator of the number of needle sets is discussed.     

Milk production and composition in reindeer (Rangifer tarandus): effect of lactational stage

Milk yield and composition of major milk constituents were measured in captive, nursing reindeer. Registration of milk production was performed during two successive lactations (2001 and 2002). The milk yield was significantly affected by week of lactation (P<0.001) and by individual (P<0.001). The lactation curve had an asymmetrical peak 3 weeks postpartum and the milk yield at peak lactation was 983 g/day (range 595-1239). The length of lactation varied from 24 to 26 weeks and average total milk production was 99.5 kg. From peak lactation the milk production decreased linearly (P<0.001) until milk production was terminated. Mean values for content of major milk constituents were 15.5% fat, 9.9% protein and 2.5% lactose. The content of fat and protein increased markedly with the lactation stage (P<0.001), while lactose showed a slight decrease (P<0.001). The milk composition was significantly affected by stage of lactation (P<0.001). There was a marginally significant decrease in protein:fat ratio (P=0.06) as protein was substituted by fat with stage of lactation. The caloric value of the milk averaged 8.7 kJ/g and increased significantly with the stage of lactation (P<0.001). The overall increase in milk gross energy content during lactation was 67.6%. The energy output averaged 7996 kJ/day at peak lactation and decreased significantly during the course of lactation (P=0.002).     

Theories of Nomadic Movement: A New Theoretical Approach for Understanding the Movement Decisions of Nenets and Komi Reindeer Herders

It is known that the relationship between humans and their animals is important for understanding many aspects of nomadic pastoralist systems, including nomadic movement. However, to date, these complex human–animal relations have not been analyzed in a way that has led to an explanatory model of nomadic movement capable of producing testable hypotheses. Based on ethnographic material collected amongst Komi and Nenets nomadic reindeer herders of the Russian Arctic, we argue that nomadic movements can be best understood as a product of the interplay that exists between animal behaviour and the herders’ skilful actions to (a) maintain herd cohesion and (b) avoid hazards, whilst deploying the minimum amount of resources (i.e., human/animal effort and use of equipment) on rounding up the herd, stopping and turning it. Ecological factors affect movement through their influence on animal behaviour, whereas non-ecological factors do so by influencing the herders’ skilful actions. We demonstrate that, based on these assumptions, it is possible to build a testable model explaining the movement of some nomadic groups.

Reindeer antlers: visual indicators of individual quality?

Fluctuating asymmetry (FA) in ornamental characters may reflect developmental stability in the translation from genotype to phenotype. Antlers of reindeer show FA, are visually conspicuous ornaments and are important in intraspecific assessment. We show that there is a negative relationship between size and asymmetry in visual antler characteristics (i.e., antler length and number of tines) among free-ranging male reindeer in rut. This indicates that individuals that develop large ornaments are better able to buffer developmental stress than individuals that develop small ornaments. There is no relationship between asymmetry in antler length and asymmetry in jaw length, suggesting that symmetry in antlers does not reflect overall body symmetry. This difference may be caused by trait-specific sensitivity to developmental stress. Such stress may partly be caused by parasites, which show a positive association with asymmetry in antlers, but no relationship to asymmetry in jaws. Our results indicate that antlers may be exposed to directional selection in a visual signaler-receiver system and that information about parasite burden may be obtained from evaluation of asymmetry in antlers developed under exposure to a multitude of environmental stresses. Received: 8 October 1996 / Accepted: 13 January 1997     

Comparative nutritional ecology of grass-feeding in a sub-Antarctic beetle: the impact of introduced species on Hydromedion sparsutum from South Georgia

South Georgia has many introduced plant and animal species, a consequence of its long history of human habitation. Introduced reindeer have a strong effect on the vegetation of the Stromness Bay area by causing the replacement of indigenous species by grazing-tolerant grasses such as the exotic Poa annua, and in certain circumstances, the indigenous Festuca contracta. Recently it has been argued that an introduced predatory carabid has contributed to declines in the abundance and an increase in the body size of adults of the indigenous perimylopid beetle Hydromedion sparsutum. However, it also appears that body size of these beetles is smaller in areas where exotic grasses predominate compared to undisturbed areas. Here we test the hypothesis that by causing the spread of poorer quality grasses, especially the exotic Poa annua, reindeer may be having an indirect effect on H. sparsutum. To do this we examined the nutritional ecology of H. sparsutum larvae on four grass species which form a major part of its diet, viz. the indigenous Parodiochloa flabellata, Phleum alpinum and Festuca contracta, and the exotic Poa annua. Larvae showed the highest growth rate on Parodiochloa flabellata, followed by Phleum alpinum, F. contracta and Poa annua. These differences are due to poorer absorption of the exotic grass, and poorer utilization of the absorbed material in the case of F. contracta. Poor growth of larvae on F. contracta appears to be due to its low water and nitrogen contents, whereas in the case of P. annua a combination of low water content and high nitrogen content may be responsible for low growth rates. Low growth rates associated with poor-quality food may lead either to a prolongation of the life cycle or of the length of feeding bouts of an insect. Neither option appears to be feasible for H. sparsutum, and this means that the outcome of feeding on poorer-quality foods would be a reduction in final adult size. This has fitness consequences for the beetle. Hence it appears that by causing the spread of grasses that are unsuitable for growth of H. sparsutum, reindeer may be having an indirect effect on this beetle species. Received: 18 August 1996 / Accepted: 7 February 1997     

Foraging conditions, tooth wear and herbivore body reserves: a study of female reindeer

Several aspects of the life history of reindeer (Rangifer tarandus) are related to the nutritional condition of the animals. Moreover, compensatory growth and fattening in summer decreases with age. The interaction of tooth wear and the standing crop of lichens on age-related variation in body size and tissue reserves was examined to evaluate the proximate causes of density-dependent food limitation on life history parameters in female reindeer. Studies in nine semi-domesticated free-ranging reindeer herds showed that molar height depended on the mean standing crop of terrestrial lichens in winter habitats. The extent of tooth wear had the strongest effect on body reserves among the oldest females (11–14 years). This indicates that severe tooth wear limits the animals′ ability to process food efficiently and, hence, to maintain their body reserves. Both tooth wear and the biomass of lichens influenced body mass in old females, probably because on heavily exploited winter ranges reindeer had to use higher proportions of lower-ranking coarser foods, especially dwarf shrubs. Received: 1 December 1997 / Accepted: 13 July 1998     

The effects of wintertime undernutrition on plasma leptin and insulin levels in an arctic ruminant, the reindeer

We examined the effects of prolonged undernutrition on plasma leptin and insulin levels and some serum protein metabolites in reindeer (Rangifer tarandus tarandus L.) during winter and spring. The reindeer (male < 1 year) were fed their preferred winter feed, low-protein lichen ad libitum for 5 weeks, followed by 40% restriction of energy for 8 weeks and refeeding with high-protein pellets for 6 weeks. The control group received high-protein reindeer pellets ad libitum throughout the experiment. Plasma leptin decreased by 46% and insulin by 54% in the lichen group already during the ad libitum period between January and February, with parallel decreases in body weight, serum total proteins, albumin and urea. Leptin remained low during most of the energy restriction period in March and April, but increased at the end of April while body weight decreased. During the refeeding period in May and June, the body weight and insulin of the lichen group increased in parallel with total proteins and urea, but leptin remained unchanged. Similar significant reductions in plasma leptin (40%) as in the lichen group also took place in the control group fed high-protein pellets ad libitum in January and February, although their feed intake, serum total proteins and body weight remained unchanged. The results show that leptin decreases in reindeer during mid-winter, independent of food or protein intake, and suggest that the decrease may be cued by seasonal factors such as the short photoperiod.     

Antibodies against Toxoplasma gondii in Fennoscandian reindeer - association with the degree of domestication

To measure the prevalence of antibodies against Toxoplasma gondii in Fennoscandian reindeer, we examined 2577 serum samples collected between 1993 and 1996 from slaughtered reindeer from Finnmark county, Norway, and from several locations in Finland. The overall prevalence in this sample was 0.9%, and the titres of the seropositives in the Direct Agglutination Test (DAT) were between 1:40 and 1:162000. Logistic regression associated seropositivity with the age of the animal, the odds ratio (OR) of adults was four when compared with calves. Seropositivity was also positively associated with corral feeding, which was used in the analysis as an indicator of domestication. No significant association was found with sex, or the frost sum of the pasture area.     

Indicating human-environmental system properties: Case study northern Fenno-Scandinavian reindeer herding

According to the contemporary ecosystem approach, integrated management of natural resources recognizes that humans, with their cultural diversity, are an integral component of many ecosystems. Therefore, the linkages of human actions with their environment have to be assessed in an integrative manner. Appropriate models and indicators, data and information for human and environmental systems are needed as well as suitable linkages between the specific components. In this paper, an indicator framework for the analysis and assessment of complex human-environmental systems is presented. An example application from a research project dealing with the development of sustainable management strategies for the husbandry of semi-domesticated reindeer in northern Fenno-Scandinavia illustrates the potentials and limitations of this framework. The concept and indicators of ecological integrity are used to assess the impacts of reindeer herding on the natural environment. Human well-being is evaluated with indicators for social and economic welfare. In conjunction with three scenarios, associated with varying land use patterns and land use priorities, the relevance of the particular components for a sustainable resource management in the case study area was estimated and recommendations to management authorities could be given.