scholarly journals Arctic ungulates at the northern edge of terrestrial life

Rangifer ◽  
1996 ◽  
Vol 16 (2) ◽  
pp. 51 ◽  
Author(s):  
David R. Klein

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.

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Pratap Kafle ◽  
Peter Peller ◽  
Alessandro Massolo ◽  
Eric Hoberg ◽  
Lisa-Marie Leclerc ◽  
...  

Abstract Rapid climate warming in the Arctic results in multifaceted disruption of biodiversity, faunal structure, and ecosystem health. Hypotheses have linked range expansion and emergence of parasites and diseases to accelerating warming globally but empirical studies demonstrating causality are rare. Using historical data and recent surveys as baselines, we explored climatological drivers for Arctic warming as determinants of range expansion for two temperature-dependent lungworms, Umingmakstrongylus pallikuukensis and Varestrongylus eleguneniensis, of muskoxen (Ovibos moschatus) and caribou (Rangifer tarandus), in the Canadian Arctic Archipelago from 1980 through 2017. Our field data shows a substantial northward shift of the northern edge of the range for both parasites and increased abundance across the expanded ranges during the last decade. Mechanistic models parameterized with parasites’ thermal requirements demonstrated that geographical colonization tracked spatial expansion of permissive environments, with a temporal lag. Subtle differences in life histories, thermal requirements of closely related parasites, climate oscillations and shifting thermal balances across environments influence faunal assembly and biodiversity. Our findings support that persistence of host-parasite assemblages reflects capacities of parasites to utilize host and environmental resources in an ecological arena of fluctuating opportunity (alternating trends in exploration and exploitation) driving shifting boundaries for distribution across spatial and temporal scales.


Rangifer ◽  
2003 ◽  
Vol 23 (5) ◽  
pp. 213 ◽  
Author(s):  
Frank L. Miller ◽  
Anne Gunn

The Peary caribou (Rangifer tarandus pearyi) was recognized as 'Threatened' by the Committee on the Status of Endangered Wildlife in Canada in 1979 and 'Endangered' in 1991. It is the only member of the deer family (Cervidae) found on the Queen Elizabeth Islands (QEI) of the Canadian High Arctic. The Peary caribou is a significant part of the region's biodiversity and a socially important and economically valuable part of Arctic Canada's natural heritage. Recent microsatellite DNA findings indicate that Peary caribou on the QEI are distinct from caribou on the other Arctic Islands beyond the QEI, including Banks Island. This fact must be kept in mind if any translocation of caribou to the QEI is proposed. The subspecies is too gross a level at which to recognize the considerable diversity that exists between Peary caribou on the QEI and divergent caribou on other Canadian Arctic Islands. The Committee on the Status of Endangered Wildlife in Canada should take this considerable diversity among these caribou at below the subspecies classification to mind when assigning conservation divisions (units) to caribou on the Canadian Arctic Islands. In summer 1961, the first and only nearly range-wide aerial survey of Peary caribou yielded a population estimate on the QEI of 25 845, including about 20% calves. There was a strong preference for range on the western QEI (WEQI), where 94% (24 363) of the estimated caribou occurred on only 24% (ca. 97 000 km2) of the collective island-landmass. By summer 1973, the overall number of Peary caribou on the QEI had decreased markedly and was estimated at about 7000 animals. The following winter and spring (1973-74), the Peary caribou population declined 49% on the WQEI. The estimated number dropping to <3000, with no calves seen by us in summer 1974. Based on estimates from several aerial surveys conducted on the WQEI from 1985 to 1987, the number of Peary caribou on the QEI as a whole was judged to be 3300-3600 or only about 13-14% of the 1961 estimate. After a partial recovery in the late 1980s and early 1990s, Peary caribou on the WQEI declined drastically between 1994 and 1997 and were estimated at an all-time known low of about 1100 animals by summer 1997. The number of Peary caribou on the QEI in summer 1997 was likely no more than 2000-2400 or only 8-9% of the 1961 estimate. The four known major die-offs of Peary caribou on the WQEI between 1973 and 1997 occurred during winter and spring periods (1 Sep-21 Jun) with significantly greater (P<0.005) total snowfall, when compared to the long-term mean obtained from 55 caribou-years (1 Jul-30 Jun), 1947/48-2001/02, of weather records from Resolute Airport on Cornwallis Island. Of ecological significance is that the die-offs occurred when the caribou were at low mean overall densities and involved similar high annual rates of loss among muskoxen (Ovibos moschatus). All of the available evidence indicates that Peary caribou (and muskoxen) on the QEI experienced die-offs from prolonged, under-nutrition (starvation) caused by relative unavailability of forage-the forage was there but it was inaccessible to the caribou due to snow and/or ice cover. We cannot control the severe weather that greatly restricts the forage supply but we should try to reduce the losses of Peary caribou from other sources-humans, predators and competitors.


ARCTIC ◽  
2020 ◽  
Vol 73 (4) ◽  
pp. 499-508
Author(s):  
Conor D. Mallory ◽  
Matthew Fredlund ◽  
Mitch W. Campbell

  In spring 2019, we conducted a comprehensive abundance and distribution survey for Peary caribou (Rangifer tarandus pearyi) and muskox (Ovibos moschatus) on Axel Heiberg Island, Nunavut, Canada. Although much of Axel Heiberg Island is rugged and extensively glaciated, areas east of the Princess Margaret mountain range have high productivity given the latitude and have supported relatively large numbers of Peary caribou and muskoxen. This region of the island has been previously identified as a potential High Arctic refugium. The last island-wide survey, in 2007, estimated 4237 muskoxen (95% confidence interval [CI] [3371:5325]) and 2291 Peary caribou (95% CI [1636:3208]); based on our 2019 results, it appears that muskox numbers have been stable on Axel Heiberg Island since then. Using distance sampling and density surface models, we estimated 3772 muskoxen (95% CI [3001:4742]) on Axel Heiberg Island during our 2019 survey. In contrast, Peary caribou, which is listed as an endangered species under the Canadian Species at Risk Act, appear to have declined dramatically from the 2007 estimate. During the 2019 survey, we observed only six Peary caribou and could not generate an island-wide estimate. Abrupt declines in numbers are characteristic of the species and are usually related to poor winter conditions such as dense snowpack or extreme weather events that result in widespread ground-fast icing. However, the limited monitoring information available at the northern extent of Peary caribou range presents major challenges to our understanding of the mechanisms leading to this near total absence of approximately 20% of range-wide Peary caribou numbers.


Author(s):  
I. Zolnikov ◽  
◽  
A. Vybornov ◽  
A. Anoikin ◽  
A. Postnov ◽  
...  

In the course of studies conducted by IAET SB RAS in the Lower Ob in 2016–2019, the understanding of the conditions for settlement of the Paleolithic population in the north of Western Siberia was significantly supplemented. Dating of a series of paleontological finds was carried out at the "Accelerated mass spectrometer of the Budker Institute of Nucle- ar Physics of SB RAS". The dates obtained show the distribution of the main representatives of the Upper Pleistocene fauna of Subarctica: Mammuthus primigenius – 50,000–15,000 BP, Coelodonta antiquitatis – 43,000–38,000 BP and 27,000–25,000 BP, Rangifer tarandus, Equus ferus – 40,000–10,000 BP, Bison sp. – 50,000–40,000 BP, Ovibos moschatus – 41,000–32,000 BP.


Parasitology ◽  
2008 ◽  
Vol 136 (2) ◽  
pp. 253-265 ◽  
Author(s):  
J. HUGHES ◽  
S. D. ALBON ◽  
R. J. IRVINE ◽  
S. WOODIN

SUMMARYMacroparasites potentially play a significant but often ignored role in the ecology and dynamics of wild ruminant populations. In the Arctic, parasites may impact on host populations by exacerbating the effects of seasonal and limited forage availability on the condition, fecundity and survival of individuals. We studied the effects of abomasal nematode parasites and warble flies, Hypoderma tarandi, on condition and pregnancy of caribou Rangifer tarandus in the Dolphin-Union herd, Nunavut, Canada. By the end of winter, female caribou over 2 years old showed a significant decrease in body weight with increasing nematode burden, and a decrease in back fat depth with increasing warble abundance. These effects were exaggerated in the non-pregnant fraction of the population. High warble larvae burdens were also associated with significantly reduced probability of being pregnant. Our research demonstrates a negative relationship between parasites and caribou condition that may have consequences for their fitness. Additionally, we discuss the possibility that muskox Ovibos moschatus share some parasite species with the caribou and could lead to elevated burdens in the sympatric host. Parasites may have been a contributory factor in a previous winter range-shift of the caribou herd and this may reflect a form of apparent competition between the two ungulate species.


Because of previous isolated reports of swimmer’s itch at the stage 1 lake, periodic surveys by sweep netting commenced in July 1990. For each of six localities covering three distinct habitat types (open bays within the lake, along the margins of permanent creeks, temporary ponds), 1 m quadrats containing all vegetation types were scoured for snails. Austropeplea snails were not present in the lake proper until February 1991, but in November 1990 they were first located in ponds along the north-east, east and south-western shorelines. Egg masses were often found attached to the undersides of nardoo (Marsilea mutica) and sometimes wrapped around the stalks and ventral surfaces of the water lily, Nymphaea gigantea. Thus its absence from the lake was attributed to the lack of established vegetation in the stage 2A lake, and from this we developed a working hypothesis that host snails were possibly vegetation-specific. Thus to facilitate recreational use, control of infected Austropeplea could be achieved by simply clearing the appropriate water plant. By July to August 1991, however, schistosome-infected Austropeplea were collected from various types of vegetation along the margins of Ross River, close to the lake. A few Amerianna and Gyraulus gilberti were found in Ti-Tree Bay contiguous with Big Bay and Round Island, which were still negative for snails. By February 1992, planorbids were present in all three habitat types, with Austropeplea in two, i.e. ponds and creeks around the lake. Until 1993, 2,365 snails were dissected to detect both patent and pre-patent Trichobilharzia infection. Four different species of snails were identified, size classed according to shell length or width using vernier calipers. Snails were crushed on a microscope slide or in a Petri dish with a few drops of water under a warm light. A heavy infection of cercariae is evident to the naked eye, but any worm-like animals were removed on to another slide, stained with two to three drops of 0.1 per cent neutral red dye, covered with a coverslip and examined microscopically. Schistosome cercariae are distinctive with their eye spots, forked tail and presence of oral and ventral suckers (see Figure 9.4). Schistosomes were recovered from 4.5 per cent and 1.7 per cent of Austropeplea and Gyraulus gilberti snails, but not from Amerianna nor Thiara. In terms of management solutions, several questions seemed paramount: • Which habitat types presented the greatest (and lowest) risk? • Which time of the year presented the greatest hazard? • Can certain indicators be used to predict infection? Statistical analysis of the presence and abundance of Austropeplea snails did not correlate with any particular vegetation type (Hurley et al. 1995) but was connected with vegetation generally. There was no clear-cut relationship with snail density and physicochemical parameters including temperature, biomass of periphyton or with percentage surface coverage. However, highest densities of Austropeplea lessoni (45/m and Amerianna

1998 ◽  
pp. 149-149

1998 ◽  
Vol 10 (2) ◽  
pp. 151-159 ◽  
Author(s):  
Peter Gravlund ◽  
Morten Meldgaard ◽  
Svante Pääbo ◽  
Peter Arctander

1992 ◽  
Vol 281 (3) ◽  
pp. 725-728 ◽  
Author(s):  
B Giardina ◽  
S G Condò ◽  
O Brix

An extensive set of data relating to the binding of oxygen by haemocyanin from the squid Todarodes sagittatus has been collected under various experimental conditions. The results obtained show that, within the range of physiological pH, the concentration of protons affects mainly the high-affinity state of the molecule without significantly affecting the low-affinity state. As far as the effect of temperature is concerned, the data show a characteristic feature which is very similar to that previously described in the case of haemoglobins from Arctic mammals such as reindeer (Rangifer tarandus) and musk ox. (Ovibos moschatus). The shape of the oxygen equilibrium curve shows strong temperature-dependence, since the overall heat of the binding of oxygen to the low-affinity state of the molecule is strongly exothermic and that to the high-affinity state is very close to zero. The results provide an outline of the intramolecular compromise that, through the interplay of temperature and protons, optimizes the loading and unloading of oxygen under the various environmental conditions experienced by this species of squid.


1997 ◽  
Vol 75 (10) ◽  
pp. 1628-1635 ◽  
Author(s):  
Steeve D. Côté ◽  
James A. Schaefer ◽  
François Messier

Synchrony of activities and time budgets of age–sex classes of muskoxen (Ovibos moschatus) was studied on Victoria Island in the Canadian High Arctic during late winter (April – late May), spring (late May – early June) and summer (mid-June – July). As revealed by the kappa (κ) coefficient of agreement, herd members exhibited significant synchrony in 79 of 82 groups. The degree of synchrony was not related to group size in mixed herds but decreased with group size in bachelor herds. Diversity in age–sex classes, group type (mixed versus bachelor), and season did not affect synchrony. However, synchrony was less among adult males than among other age–sex classes. Muskoxen were more synchronised at the start of activity bouts than at the end. As revealed by principal components analysis, calves tended to spend more time lying and standing and less time feeding than other age–sex classes. In addition, males in bachelor groups tended to feed more and rest less than males in mixed herds. Duration of active and lying bouts was not affected by age–sex class. Length of active bouts did not change with season, but lying bouts decreased in length significantly from late winter to spring and from spring to summer. We suggest that synchrony of activities maintains group cohesion but constrains the time budget of some group members, especially adult males.


2020 ◽  
Vol 6 (4) ◽  
pp. 529-544
Author(s):  
Noémie Boulanger-Lapointe ◽  
Greg H.R. Henry ◽  
Esther Lévesque ◽  
Alain Cuerrier ◽  
Sarah Desrosiers ◽  
...  

Berry shrubs are found across the circumpolar North where they are an important source of food for people and animals. However, the environmental controls on berry productivity in these regions is poorly understood. This study presents the results of an ongoing berry productivity monitoring program for Empetrum nigrum L., Vaccinium uliginosum L., and Vaccinium vitis-idaea L. from the forest–tundra ecotone to the high Arctic in Canada. Berry productivity was the highest recorded for these species with up to 119 berries/m2 (E. nigrum) and 661 berries/m2 (V. uliginosum) measured at one plot in Pangnirtung. On average, berry productivity for E. nigrum and V. uliginosum was higher toward the northern edge of the species distribution range. The climate variables important for the productivity of V. uliginosum in high Arctic sites were closely associated with the onset of the growing season and water availability during the growing season, whereas those important in the low Arctic sites reflected conditions during the growing season. None of the climate variables used were associated with the productivity of E. nigrum and V. vitis-idaea, likely due to complex responses and length of the time-series, thus highlighting the importance of continued monitoring in partnership with northern people and institutions.


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