Arctic Ungulates Research Articles

10th Arctic Ungulate Conference

The 10th Arctic Ungulate Conference was organised by the Department of Arctic Biology and held at the University of Tromsø, Norway, 9-13 August 1999. The conference continued a series of nine conferences devoted to Arctic ungulates, including five International Reindeer/Caribou Symposia, two International Muskox Symposia and two Arctic Ungulate Conferences. Two hundred delegates from 14 countries attended and presented more than 150 scientific papers, making it one of the biggest Arctic Ungulate Conferences ever. The scientific and social programme as well as the abstracts have been published in Rangifer Report No. 4, 1999.

Key note presentations, 10th Arctic Ungualate Conference, Tromsø, Norway, 1999

Two hundred delegates from 14 countries attended and presented more than 150 scientific papers, making it one of the biggest Arctic Ungulate Conferences ever. The scientific and social programme as well as the abstracts have been published in Rangifer Report No. 4, 1999. In an important break with normal practice, keynote speakers included scientists of international reputation who do not normally work with Arctic ungulates. They were asked to review recent work in northern species/ecosystems thus providing the conference with novel criticism and new perpectives. Their papers are published in this volume. Delegates' papers will be published in later issues of Rangifer. The Conference also included a Circumpolar PhD-Network in Arctic Environmental Studies (CAES) workshop: "Reindeer 2000", attended by 47 participants presenting 25 student contributions, 5 keynote lectures and 3 introductory speeches. A Rangifer Special Issue with workshop papers is planned for publication later in 2000.

Aspects of the ecology of mat-forming lichens

Lichen species in the genera Cladonia (subgenus Cladina), Cetraria, Stereocaulon and Alectoria are important vegetation components on well-drained terrain and on elevated micro-sites in peatlands in boreal-Arctic regions. These lichens often form closed mats, the component thalli in which grow vertically upwards at the apices and die off in the older basal regions; they are therefore only loosely attached to the underlying soil. This growth habit is relatively unusual in lichens being found in <0.5% of known species. It might facilitate internal nutrienr recycling and higher growth rates and, together with the production of allelochemicals, it might underlie the considerable ecological success of mat-forming lichens; experiments to critically assess the importance of these processes are required. Mat-forming lichens can constitute in excess of 60% of the winter food intake of caribou and reindeer. Accordingly there is a pressing need for data on lichen growth rates, measured as mass increment, in order to help determine the carrying capacity of winter ranges for rhese herbivores and to better predict recovery rates following grazing. Trampling during the snow-free season fragments lichen thalli; mat-forming lichens regenerate very successfully from thallus fragments provided trampling does nor re-occur. Frequent recurrence of trampling creates disturbed habitats from which lichens will rapidly become eliminated consistent with J.P. Grime's CSR strategy theory. Such damage to lichen ground cover has occurred where reindeer or caribou are unable to migrate away from their winter range such as on small islands or where political boundaries have been fenced; it can also occur on summer range that contains a significant lichen component and on winter range where numbers of migrarory animals become excessive. Species of Stereocaulon, and other genera that contain cyanobacteria (most notably Peltigera and Nephroma), are among the principal agents of nitrogen fixation in boreal-arctic regions. Stereocaulon-dominated subarctic woodlands provide excellent model systems in which to investigate the role of lichens in nitrogen cycling. Mat-forming lichens are sensitive indicators of atmospheric deposition partly because they occur in open situations in which they intercept precipitation and particulates directly with minimal modification by vascular plant overstoreys. Data from both the UK and northern Russia are presented to illustrate geographical relationships between lichen chemistry and atmospheric deposition of nitrogen and acidity. The ecology of mat-fotming lichens remains under-researched and good opportunities exist for making significant contributions to this field including areas that relate directly to the management of arctic ungulates.

Are arctic ungulates physiologically unique?

Reindeer/caribou (Rangifer tarandus) and muskoxen (Ovibos moschatus) are the arctic ungulates. Few studies have been carried out to directly compare their level of physiological uniqueness with similar species in the same family. The approach adopted in this review has been to compare data within family for physiological parameters including reproduction, nutrition and growth, to attempt to place the adaptations of reindeer/caribou and muskoxen in context. It is concluded that both species have unique adaptations to their environment which are likely to be specific to the Arctic. An hypothesis is advanced that some adaptations are constrained not only by the long intense winters, but also by the need to exploit the brief summers. The review has highlighted considerable gaps in understanding of some key physiological parameters for many species. This incompleteness in some ways mitigated the original goal of the project, but provisional conclusions are presented.

Contaminants in food chains of arctic ungulates: what have we learned from the Chernobyl accident?

The Chernobyl accidenr of 1986 caused radioactive contamination of widespread areas of reindeer pasture in Scandinavia. Reindeer {Rangifer tarandus) are especially exposed to radioactive fallout due to their wintet diet, of which lichens are an important part. Much knowledge about the transfer of radiocaesium to reindeer, and via reindeer meat to man, was accumulated by intense scientific investigations, undertaken during the 1960s and 1970s, following nuclear weapons testing. Various ways to reduce the transfer of radiocaesium to animals and humans were also developed during this time. Much of the older knowledge proved to be of great value in the attempts to determine potential consequences of the Chernobyl accident and to suggest possible ways to ameliorate the effects of contamination. After Chernobyl, not only did reindeer prove to be a problem; many other food products originating ftom natural and semi-natural ecosystems were found to accumulate significant amounts of radiocaesium. Intense scientific work has produced new knowledge about the role of ungulates in the transfer of nutrients and contaminants within these systems. Different measures, like providing uncontaminated feed, use of caesium binders, altering the time of slaughter have been used with good results to minimize the transfer of radiocaesium to animals grazing natural pastures. The high cost of countermeasures has enforced consideration of cost against risk, which may also be of general interest with respect to other forms of pollution. Information, introduction of countermeasures and so forth would be more efficient in case a similar accident were to happen again. The Chernobyl accident is an obvious example of how human failures when dealing with a modern technical system can have global consequences and also be a potential threat to what we like to think of as the unspoiled wilderness of the Arctic.

Proceedings of the 2nd International Arctic Ungulate Conference, Fairbanks, Alaska, 13-17 Aug 1995: Issue No. 2

<p>This issue of the proceedings of AUC 1995 is the 2nd of four issues. Issues 1, 3 and 4 are found respectively in Rangifer 1996, 16 (2): 49-92; 1997, 17 (3): 10-138 ; 1998, 18 (3-4): 99-154. A list of contents of the four proceedings issues is found in the latter proceedings issue.</p>

Proceedings Issue No. 3 - 2nd International Arctic Ungulate Canference

<p>2nd AUC was arranged at the University of Alaska Fairbanks, USA, 13-17 August 1995.</p>

2nd International Arctic Ungulate Conference

The 2nd International Arctic Ungulate Conference was held 13-17 August 1995 on the University of Alaska Fairbanks campus. The Institute of Arctic Biology and the Alaska Cooperative Fish and Wildlife Research Unit were responsible for organizing the conference with assistance from biologists with state and federal agencies and commercial organizations. David R. Klein was chair of the conference organizing committee. Over 200 people attended the conference, coming from 10 different countries. The United States, Canada, and Norway had the largest representation. The conference included invited lectures; panel discussions, and about 125 contributed papers. There were five technical sessions on Physiology and Body Condition; Habitat Relationships; Population Dynamics and Management; Behavior, Genetics and Evolution; and Reindeer and Muskox Husbandry. Three panel sessions discussed Comparative caribou management strategies; Management of introduced, reestablished, and expanding muskox populations; and Health risks in translocation of arctic ungulates. Invited lectures focused on the physiology and population dynamics of arctic ungulates; contaminants in food chains of arctic ungulates and lessons learned from the Chernobyl accident; and ecosystem level relationships of the Porcupine Caribou Herd.

Arctic ungulates at the northern edge of terrestrial life

The two ungulate species that occur in the High Arctic, Rangifer tarandus and Ovibos moschatus, exhibit considerable adaptive plasticity in response to habitat variability throughout their circumpolar distribution. R. tarandus, however, has a much wider latitudinal distribution and occurs within a wider range of both forest and tundra habitat types than 0. moschatus, reflecting greater morphological, physiological, and behavioral plasticity. As a consequence, muskoxen have been less successful than caribou and reindeer in maintaining populations at their southern limits. Muskoxen, however, existed throughout Pleistocene glaciations in the cold periglacial steppes of Eurasia and North America and find the closest analog to this vegetation type in the High Arctic, where they have been more successful than R. tarandus in maintaining their populations.

Proceedings Issue No. 1 - 2nd Arctic Ungulate Conference

The 2nd International Arctic Ungulate Conference was held 13-17 August 1995 on the University of Alaska Fairbanks campus. The Institute of Arctic Biology and the Alaska Cooperative Fish and Wildlife Research Unit were responsible for organizing the conference with assistance from biologists with state and federal agencies and commercial organizations. David R. Klein was chair of the conference organizing committee. Over 200 people attended the conference, coming from 10 different countries. The United States, Canada, and Norway had the largest representation. The conference included invited lectures; panel discussions, and about 125 contributed papers.

Extreme Seasonal Growth in Arctic Deer: Comparisons and Control Mechanisms

Synopsis. Arctic ungulates have the capacity to voluntarily restrict growth to times of the year of predictable high quality seasonal herbage abun? dance. The constraints ofthe arctic environment mean that not only must the timing of this growth seasonality be accurate but growth rate must be maximised for a short period of time. It is known that daylength is a critical cue for the timing of seasonal rhythms of growth; a manipulated photoperiod of 16L:8D stimulates out of season growth in reindeer during winter and this growth is associated with an increase in the plasma levels of insulin like growth factor 1 (IGF 1). In contrast a manipulated pho? toperiod of 8L: 16D delays the spring rise in growth. There is good evidence from a boreal cervid, the red deer, that the number of hours of day influences growth rate also and this is associated with IGF 1. Thus day? length may have a dual role in growth seasonality, timing and amplitude. Although the mechanisms underlying the timing of rhythms by daylength are partly understood a putative role for daylength in controlling the rate of an event is a new concept.

The dynamics of caribou and muskoxen foraging in arctic ecosystems

Forage system characteristics Numbers of caribou (Rangifer tarandus) and muskoxen (Ovibos moschatus) in the Northwest Territories, Canada have changed rapidly in the last few decades (e.g. Gun et al. 1991). Our ability to respond to questions raised by those rapid changes is, however, compromised by our ignorance of the dynamics of the relationship between arctic ungulates and their forage which in turn inhibits our understanding of the population dynamics. The arctic ecosystem is relatively simple in terms of species diversity and herbivore numbers fluctuate against a background of unpredictably variable weather: a simple and changeable system is more easily stripped down to its essential components to describe their interactions. Arctic ecosystems have three dominant attributes which are the salient points in my conceptual model proposed here to unravel the population dynamics of arctic herbivores, (a) Plant productivity is restricted to brief annual pulses; (b) the weather is highly unpredictable and (c) most of the biomass is below ground locked into a slow cycle of decomposition. The nutrient input in tundra ecosystems is low and mostly slowly cycled through soil organic matter at the characteristic cool ambient temperatures. Plants depend heavily on the internal recycling of nutrients from storage tissue below ground. The tie-up of plant nutrients in detritus opens an accelerating role for herbivory in nutrient recycling animal fecal material breaks down and releases nutrients to the plants more rapidly than the overall detritus pool (Dowding et al. 1981). Muskoxen which forage in herds, graze intensively and deposit large amounts of dung in situ, wil l have a larger role in nutrient recycling than caribou within the plant communities where they forage. Caribou forage in smaller groups and graze extensively while walking. Arctic plants have a pulse of growth restricted by temperatures to a brief season. The onset of plant growth varies by weeks (Svoboda 1977, Muc 1977). Most plants are conservative and complete their growing season within a fixed period despite annual variations in the duration of the potential growing season. Flowering varies between years and is depressed by as much as 80% following a late cool season but productivity of green plant biomass in meadows is less responsive to summer temperature (Muc 1977, Svoboda 1977).

Survival strategies in arctic ungulates

Arctic ungulates usually neither freeze nor starve to death despite the rigours of winter. Physiological adaptations enable them to survive and reproduce despite long periods of intense cold and potential undernutrition. Heat conservation is achieved by excellent insulation combined with nasal heat exchange. Seasonal variation in fasting metabolic rate has been reported in several temperate and sub-arctic species of ungulates and seems to occur in muskoxen. Surprisingly, there is no evidence for this in reindeer. Both reindeer and caribou normally maintain low levels of locomotor activity in winter. Light foot loads are important for reducing energy expenditure while walking over snow. The significance and control of selective cooling of the brain during hard exercise (e.g. escape from predators) is discussed. Like other cervids, reindeer and caribou display a pronounced seasonal cycle of appetite and growth which seems to have an intrinsic basis. This has two consequences. First, the animals evidently survive perfectly well despite enduring negative energy balance for long periods. Second, loss of weight in winter is not necessarily evidence of undernutrition. The main role of fat reserves, especially in males, may be to enhance reproductive success. The principal role of fat reserves in winter appears to be to provide a supplement to, rather than a substitute for, poor quality winter forage. Fat also provides an insurance against death during periods of acute starvation.