Regional Congruence of Vegetation and Summer Climate Patterns in the Queen Elizabeth Islands, Northwest Territories, Canada

Edlund, S A; Alt, B T

doi:10.14430/arctic1635

Cited by 171 publications

(217 citation statements)

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“…Hereafter, we refer to these six islands as the 'Bathurst Island complex' and to the southwestern islands as the 'Melville-Prince Patrick islands complex.' Climate patterns and vegetation vary regionally and locally across the High Arctic QEI (e.g., Courtin and Labine, 1977;Maxwell, 1981Maxwell, , 1997Edlund, 1983Edlund, , 1990Edlund and Alt, 1989;Thomas et al, 1999).…”

Section: Methodsmentioning

confidence: 99%

Catastrophic Die-off of Peary Caribou on the Western Queen Elizabeth Islands, Canadian High Arctic

Miller¹,

Gunn²

2003

ARCTIC

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ABSTRACT. The Peary caribou (Rangifer tarandus pearyi) is an endangered species in Canada, having been in an overall decline since 1961. Sightings of Peary caribou were compared from two aerial searches, in 1993 and 1998, on Bathurst and its neighbouring islands, western Queen Elizabeth Islands in the Canadian High Arctic. The comparison indicated a near-total (98%) cataclysmic decline in the number of Peary caribou seen per unit of search effort. In summer 1993, 2400 caribou were counted during 33.8 h of low-level helicopter searches. In contrast, in summer 1998, only 43 caribou were seen within the same area during 35.2 h of low-level helicopter searches. The frequency of observation was markedly different: 118.3 caribou/100 min in 1993, but only 2.0 caribou/100 min in 1998. The number of carcasses indicated that the decline resulted from deaths and not from mass emigration. Males died at a disproportionately higher rate than females among all 1+ yr old caribou, and bulls (4+ yr) compared to cows (3+ yr) had died at an even greater rate. Widespread, prolonged, exceptionally severe snow and ice conditions from 1994 -95 to 1996 -97 caused the die-off. Trends in snowfall are consistent with predictions for global warming in the western Canadian High Arctic. Future climate change may increase the frequency of years with unfavorable snow and ice conditions, which could prevent or at least impede future recovery of Peary caribou populations on the western Queen Elizabeth Islands, particularly to sizes that would support subsistence harvesting.Key words: Peary caribou, Rangifer tarandus pearyi, cataclysmic die-off, western Queen Elizabeth Islands RÉSUMÉ. Le caribou de Peary (Rangifer tarandus pearyi) est une espèce en péril au Canada, vu qu'elle a connu une diminution globale depuis 1961. On a comparé des observations du caribou de Peary faites lors de deux recherches aériennes menées en 1993 et 1998 sur l'île de Bathurst et les îles avoisinantes, celles de la Reine-Élisabeth occidentales dans l'Extrême-Arctique canadien. La comparaison a révélé un déclin cataclysmique quasi-total (98 %) du nombre de caribous de Peary aperçus par unité d'activité de recherche. En été 1993, on a dénombré 2400 caribous durant 33,8 heures de recherches par hélicoptère volant à basse altitude. En revanche, durant l'été 1998, on n'a aperçu que 43 caribous dans la même zone durant 35,2 heures de survol à basse altitude en hélicoptère. La fréquence des observations était nettement différente: 118,3 caribous/100 min en 1993, mais seulement 2,0 caribous/100 min en 1998. Le nombre de carcasses a démontré que le déclin était dû à la mort des animaux et non à une émigration massive. Les mâles mouraient à un taux supérieur à celui des femelles de façon disproportionnée parmi tous les caribous âgés de plus d'un an, et, en comparaison avec les femelles de plus de trois ans, les mâles de plus de quatre ans avaient péri à un taux encore plus élevé. La mortalité massive était due à des conditions d'enneigement et de glace généralisées et persistantes ...

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Section: Methodsmentioning

confidence: 99%

Catastrophic Die-off of Peary Caribou on the Western Queen Elizabeth Islands, Canadian High Arctic

Miller¹,

Gunn²

2003

ARCTIC

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“…Plant growth is limited to the short snow-free season which typically lasts from mid-June to the end of August. Soil conditions and plant communities reflect the local water supply (Edlund & Alt, 1989;Nettleship & Smith, 1975;Sheard & Geale, 1983). Uplands and plateaus are comparatively dry with a low total plant cover; plant communities in these areas consist of scattered herbaceous perennials with varying amounts of lichen (Sheard & Geale, 1983).…”

Section: Study Areamentioning

confidence: 99%

Spatio-temporal sensitivity of MODIS land surface temperature anomalies indicates high potential for large-scale land cover change detection in Arctic permafrost landscapes

Muster

Langer

Abnizova

et al. 2015

Remote Sensing of Environment

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The accelerated warming of the Arctic climate may alter the local and regional surface energy balances, for which changing land surface temperatures (LSTs) are a key indicator. Modeling current and anticipated changes in the surface energy balance requires an understanding of the spatio-temporal interactions between LSTs and land cover, both of which can be monitored globally by measurements from space. This paper investigates the accuracy of the MODIS LST/Emissivity Daily L3 Global 1 km V005 product and its spatio-temporal sensitivity to land surface properties in a Canadian High Arctic permafrost landscape. The land cover ranged from fully vegetated wet sedge tundra to barren rock. MODIS LSTs were compared with in situ radiometer measurements from wet tundra areas collected over a 2-year period from July 2008 to July 2010 including both summer and winter conditions. The accuracy of the MODIS LSTs was −1.1°C with a root mean square error of 3.9°C over the entire observation period. Agreement was lowest during the freeze-back periods where MODIS LST showed a cold bias likely due to the overrepresentation of clear-sky conditions. A multi-year analysis of LST spatial anomalies, i.e., the difference between MODIS LSTs and the MODIS LST regional mean, revealed a robust spatiotemporal pattern. Highest variability in LST anomalies was found during freeze-up and thaw periods as well as for open water surface in early summer due to the presence or absence of snow or ice. The summer anomaly pattern was similar for all three years despite strong differences in precipitation, air temperature and net radiation. Summer periods with regional mean LSTs above 5.0°C showed the greatest spatial diversity with four distinct 2.0°C classes. Summer anomalies ranged from −4.5°C to 2.6°C with an average standard deviation of 1.8°C. Dry ridge areas heated up the most, while wetland areas and dry areas of sparsely vegetated bedrock with a high albedo remained coolest. The observed summer LST anomalies can be used as a baseline against which to evaluate both past and future changes in land surface properties that relate to the surface energy balance. Summer anomaly classes mainly reflected a combination of albedo and surface wetness. The potential to use this tool to monitor surface drying and wetting in the Arctic should therefore be further explored. A multi-sensor approach combining thermal satellite measurements with optical and radar imagery promises to be an effective tool for a dynamic, process-based ecosystem monitoring scheme.

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“…Although their study included only three subarctic or boreal sites, it offers a global indicator of tree line climate for more intensive testing at the regional and local levels. Thawing degree-days (TDD), the cumulative number of daily heat units above 0˚C, is a bioclimatic measure used in relation to vegetation zonation and climate change impacts on vegetation in Arctic tundra (Edlund and Alt, 1989;Walker, 2000;Hollister et al, 2005), the boreal foresttundra transition zone (Rouse, 1991), and subarctic alpine regions (Callaghan et al, 2010). TDD can be a useful indicator of the thermal potential for forest species expansion into tundra areas (Sundqvist et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Climatology of the Forest-Tundra Ecotone at a Maritime Subarctic-Alpine Site, Mealy Mountains, Labrador

Jacobs¹,

Chan²,

Sutton³

2014

ARCTIC

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ABSTRACT. Climatological investigations were conducted from 2001 to 2009 in the central Mealy Mountains, Labrador (53.6˚ N), as part of interdisciplinary research on tree line ecology and climate change. The aim was to describe local climatic and edaphic variables along an altitudinal gradient from the closed forest edge to the alpine tundra and to relate recent changes in regional climate to potential changes in the forest tundra ecotone. Results show relatively warm, moist summers and cool winters, with abundant precipitation and moderate to gale-force winds. At ca. 600 m a.s.l., the tree line was characterized by 694 ± 85 growing degree-days and a mean July air temperature of 12.9 ± 0.8˚C. Growing season soil temperatures of ca. 8˚C were similar across the forest-tundra ecotone, but their seasonal regimes differed among subzones. Soil nutrient fluxes showed some variation but no consistent pattern that would suggest nutrients as a limiting factor. Snow depth in the forest-tundra subzone was more variable than in the forest, indicating that microtopography is an important factor for tree survival there in winter. Comparisons of the field data with long-term regional climatic and hydrographic records show that conditions have become warmer and drier in the most recent decade compared with the previous half-century or more. Concurrent vegetation studies indicate that changes expected with a warming climate are already occurring.Key words: Labrador, subarctic-alpine climate, forest-tundra ecotone, growing degree-days, soil temperature, nutrient flux, water balance, climate warming RÉSUMÉ. De 2001 à 2009, des études climatologiques ont été effectuées dans les monts centraux Mealy, au Labrador (53,6˚ N) dans le cadre d'une recherche interdisciplinaire sur l'écologie de la limite forestière et le changement climatique. Ces études avaient pour but de décrire les variables climatiques et édaphiques locales le long d'une pente altitudinale allant de la lisière de la forêt dense jusqu'à la toundra alpine. Elles avaient également pour but de faire le lien entre les récents changements enregistrés dans le climat régional et les changements susceptibles de se produire dans l'écotone de la toundra forestière. Les résultats montrent des étés humides et relativement chauds ainsi que des hivers frais, avec des précipitations abondantes et des vents allant de modérés à coups de vent. À environ 600 m ASL, la limite forestière était caractérisée par 694 ± 85 degrés-jours de croissance et une température de l'air moyenne de 12,9 ± 0,8 ˚C en juillet. En saison de croissance, les températures du sol d'environ 8 ˚C étaient semblables à la grandeur de l'écotone de la forêt-toundra, bien que les régimes saisonniers différaient d'une sous-zone à l'autre. Les flux de nutriments du sol affichaient une certaine variation, mais il n'existait aucun modèle uniforme laissant entrevoir que les nutriments pouvaient être un facteur limitant. L'épaisseur de la neige dans la sous-zone forêt-toundra variait plus que dans la forêt, ce qui indique que...

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Regional Congruence of Vegetation and Summer Climate Patterns in the Queen Elizabeth Islands, Northwest Territories, Canada

Cited by 171 publications

References 54 publications

Catastrophic Die-off of Peary Caribou on the Western Queen Elizabeth Islands, Canadian High Arctic

Catastrophic Die-off of Peary Caribou on the Western Queen Elizabeth Islands, Canadian High Arctic

Spatio-temporal sensitivity of MODIS land surface temperature anomalies indicates high potential for large-scale land cover change detection in Arctic permafrost landscapes

Climatology of the Forest-Tundra Ecotone at a Maritime Subarctic-Alpine Site, Mealy Mountains, Labrador

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