Fifty-four new Canadian provincial records of aleocharine beetles (Staphylinidae), including three new Canadian records and one new North American record, are presented. Of these, 33 are new ...provincial records for Saskatchewan, 14 for Alberta, two for British Columbia, three for Manitoba, two for the Northwest Territories and one for the Yukon Territory. The following are new Canadian records: Trichiusapilosa Casey formerly reported from Nova Scotia and Ontario as Trichiusapostica Casey, Acrotonarecondita (Erichson) and the adventive Palaearctic Athetanigra (Kraatz), which is also a new North American record. Bionomics information and new locality records are provided. The following new synonyms of Trichiusapilosa Casey are established: Trichiusaatra Casey, Trichiusamonticola Casey, Trichiusaparviceps Casey, and Trichiusapostica Casey. The numbers of Aleocharinae remaining to be discovered in Canadian provinces and territories are discussed.
References to a "New North" have snowballed across popular media in the past 10 years. By invoking the phrase, scientists, policy analysts, journalists and others draw attention to the collision of ...global warming and global investment in the Arctic today and project a variety of futures for the region and the planet. While changes are apparent, the trope of a "New North" is not new. Discourses that appraised unfamiliar situations at the top of the world have recurred throughout the twentieth century. They have also accompanied attempts to cajole, conquer, civilize, consume, conserve and capitalize upon the far north. This article examines these politics of the "New North" by critically reading "New North" texts from the North American Arctic between 1910 and 2010. In each case, appeals to novelty drew from evaluations of the historical record and assessments of the Arctic's shifting position in global affairs. "New North" authors pinpointed the ways science, state power, capital and technology transformed northern landscapes at different moments in time. They also licensed political and corporate influence in the region by delimiting the colonial legacies already apparent there.
Given these tendencies, scholars need to approach the most recent iteration of the "New North" carefully without concealing or repeating the most troubling aspects of the Arctic's past.
The Pliocene (5.3–2.6 Ma), an epoch with periods of climatic warmth and possible analogue for the future, has been well‐characterized globally by marine geochemical proxies. However, far less is ...known about Pliocene warmth at continental high latitudes, where the greatest impacts of warming are expected. This study seeks to better characterize the Pliocene climate of central Alaska and Yukon based on a reconstruction of the stable hydrogen isotope composition of precipitation relative to modern (ΔδDprecip) preserved in volcanic glass shards, a proxy for mean air temperature. The studied tephras are from a regional suite of outcrops that, when assembled into a composite record of ΔδDprecip, can be used to resolve broad trends during the late Miocene (6.7–5.86 Ma, n = 5), Pliocene (5.08–2.81 Ma, n = 7), and late Pleistocene (0.74–0.03 Ma, n = 3). These trends indicate that Pliocene ΔδDprecip estimates were generally more enriched in heavy isotopes than the latest Miocene, Pleistocene, and modern intervals. ΔδDprecip is likely influenced by changes in regional boundary conditions including orographic barriers, depositional environments, and ocean‐atmospheric circulation, but ΔδDprecip trends are most consistent with reconstructed temperatures from Yukon‐Alaska and North Pacific marine records. As such, this record appears predominantly sensitive to regional climate. Furthermore, qualitative temperature inferences from branched‐chain glycerol dialkyl glycerol tetraethers (brGDGTs) from four of our sites dating between 2.91 and 6.17 Ma corroborate elevated temperatures during the early Pliocene. Overall, this study demonstrates the viability of volcanic glass δD as a proxy for ΔδDprecip and late Cenozoic climate change in this region.
Key Points
The 2H/1H of hydrated volcanic glass shards in late Cenozoic ash beds in Yukon and Alaska document changes in meteoric 2H/1H ratios
The 2H/1H glass record is most coherent with other terrestrial and marine temperature reconstructions, indicating strong climate sensitivity
Branched‐chain glycerol dialkyl glycerol tetraether (brGDGT) biomarkers from some of the same deposits corroborate significantly elevated temperatures during the early Pliocene
Infiltration into frozen and unfrozen soils is critical in hydrology, controlling active layer soil water dynamics and influencing runoff. Few Land Surface Models (LSMs) and Hydrological Models (HMs) ...have been developed, adapted or tested for frozen conditions and permafrost soils. Considering the vast geographical area influenced by freeze/thaw processes and permafrost, and the rapid environmental change observed worldwide in these regions, a need exists to improve models to better represent their hydrology. In this study, various infiltration algorithms and parameterisation methods, which are commonly employed in current LSMs and HMs were tested against detailed measurements at three sites in Canada's discontinuous permafrost region with organic soil depths ranging from 0.02 to 3 m. Field data from two consecutive years were used to calibrate and evaluate the infiltration algorithms and parameterisations. Important conclusions include: (1) the single most important factor that controls the infiltration at permafrost sites is ground thaw depth, (2) differences among the simulated infiltration by different algorithms and parameterisations were only found when the ground was frozen or during the initial fast thawing stages, but not after ground thaw reaches a critical depth of 15 to 30 cm, (3) despite similarities in simulated total infiltration after ground thaw reaches the critical depth, the choice of algorithm influenced the distribution of water among the soil layers, and (4) the ice impedance factor for hydraulic conductivity, which is commonly used in LSMs and HMs, may not be necessary once the water potential driven frozen soil parameterisation is employed. Results from this work provide guidelines that can be directly implemented in LSMs and HMs to improve their application in organic covered permafrost soils.
Repeat measurements from long-term plots provide precise data for studying plant community change. In 2010, we visited a remote location in Yukon, Canada, where a detailed survey of alpine tundra ...communities was conducted in 1968. Plant community composition was resurveyed on the same four slopes using the same methods as the original study. Species richness and diversity increased significantly over the 42 years and non-metric multidimensional scaling indicated that community composition had also changed significantly. However, the direction and magnitude of change varied with aspect. Dominant species were not replaced or eliminated but, instead, declined in relative importance. Fine-scale changes in vegetation were evident from repeat photography and dendro-ecological analysis of erect shrubs, supporting the community-level analysis. The period of study corresponds to a mean annual temperature increase of 2°C, suggesting that climate warming has influenced these changes.
Plant and insect macrofossil assemblages dating to the full-glacial (late Wisconsinan) are rare from eastern Beringia. Here we present an assemblage of fossil pollen, insect and plant macrofossils ...recovered from alluvium at the Bluefish Exposure, northern Yukon Territory. Nine AMS radiocarbon ages place these data between ca. 18,880–16,440
14C yr BP (22,313–19,597 cal. yr BP). These data indicate that xeric steppe, rich in bunchgrasses
Poa and
Elymus,
Artemisia frigida and diverse forbs was interspersed within a mosaic of local vegetation types, including mid-rich fens, mesic graminoid meadows, steppe-tundra and herb-tundra. Macrofossils and minor pollen of tundra forbs suggest steppe-tundra plant associations within midslope elevations and discontinuous herb-tundra on high elevation uplands on exposed bedrock ridges. The composition and distribution of local vegetation was dependent on available moisture, drainage, aspect and elevation. Compositional and physiognomic similarities can be made with extrazonal steppe-dominated dry slopes and high elevation steppe-tundra ecotones in central Alaska and Yukon Territory. Our paleoecological data reflect environments inhabited by the diverse late Pleistocene Bluefish Caves fauna, including woolly mammoth, horse, steppe bison, and saiga antelope.
We tested the adaptive stress hypothesis that male arctic ground squirrels (Urocitellus parryii) exhibit a stress response over the course of the breeding season that is characterized by increasing ...free cortisol concentrations, increasing mobilization of stored energy, and decreasing physical condition. We assessed the functioning of the hypothalamic-pituitary-adrenal axis by measuring cortisol levels in response to the stress of capture and in response to a hormone challenge protocol (dexamethasone suppression and adrenocorticotropic hormone stimulation). We measured blood glucose levels, free fatty acids, white blood cells, and hematocrit to assess the downstream physiological responses to cortisol. Immediately after spring emergence, male arctic ground squirrels had ample free abdominal fat and few signs of wounding. By the end of the breeding season 3 wk later, visible fat reserves were almost entirely gone, and most males had extensive wounds. Total plasma cortisol concentrations increased over this period, but so did corticosteroid-binding capacity, resulting in no change in the free cortisol response to capture. We found no significant changes in how the animals responded to our hormone challenges, contrary to our prediction that the stress axis should increase free cortisol production. Even though we found no change in the functioning of the stress axis, all of the downstream measures suggested that male arctic ground squirrels are chronically exposed to high cortisol concentrations. Over the breeding season, blood glucose increased, fat stores and circulating free fatty acids were depleted, and both hematocrit levels and white blood cell counts decreased significantly. Our data suggest that a more complex relationship between the stress axis and downstream measures of stress exists than that proposed by the adaptive stress hypothesis. We propose several nonexclusive, testable mechanisms that could explain our observations.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NMLJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Arctic and sub-arctic watersheds are undergoing significant changes due to recent climate warming and degrading permafrost, engendering enhanced monitoring of arctic rivers. Smaller catchments ...provide understanding of discharge, solute flux and groundwater recharge at the process level that contributes to an understanding of how larger arctic watersheds are responding to climate change. The North Klondike River, located in west central Yukon, is a sub-alpine permafrost catchment, which maintains an active hydrological monitoring station with a record of >40 years. In addition to being able to monitor intra-annual variability, this data set allows for more complex analysis of streamflow records. Streamflow data, geochemistry and stable isotope data for 2014 show a groundwater-dominated system, predominantly recharged during periods of snowmelt. Radiocarbon is shown to be a valuable tracer of soil zone recharge processes and carbon sources. Winter groundwater baseflow contributes 20 % of total annual discharge, and accounts for up to 50 % of total river discharge during the spring and summer months. Although total stream discharge remains unchanged, mean annual groundwater baseflow has increased over the 40-year monitoring period. Wavelet analysis reveals a catchment that responds to El Niño and longer solar cycles, as well as climatic shifts such as the Pacific Decadal Oscillation.
Dedicated to Professor Peter Fritz on the occasion of his 80th birthday
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