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IntroductionThe Arctic is home to about 21000 described species, many of which are specifically adapted to a cold climate (CAFF 2013). As this diversity is under pressure from several sources, [...], Chironomid flies (non-biting midges) are among the most abundant and diverse animals in Arctic regions, but detailed analyses of species distributions and biogeographical patterns are hampered by challenging taxonomy and reliance on morphology for species-level identification. Here we take advantage of available DNA barcode data of Arctic Chironomidae in BOLD to analyse similarities in species distributions across a northern Nearctic--West Palearctic gradient. Using more than 260 000 barcodes representing 4666 BINs (Barcode Index Numbers) and 826 named species (some with interim names) from a combination of public and novel data, we show that the Greenland chironomid fauna shows affinities to both the Nearctic and the West Palearctic regions. While raw taxon counts indicate a strong Greenland--North American affinity, comparisons using Chao's dissimilarity metric support a slightly higher similarity between Greenland and West Palearctic chironomid communities. Results were relatively consistent across different definitions of species taxonomic units, including morphologically determined species, BINs, and superBINs based on a ~4.5% threshold. While most taxa found in Greenland are shared with at least one other region, reflecting circum-Arctic dispersal, our results also reveal that Greenland harbours a small endemic biodiversity. Our exploratory study showcases how DNA barcoding efforts using standardized gene regions contribute to an understanding of broad-scale patterns in biogeography by enabling joint analysis of public DNA sequence data derived from diverse prior studies.Key words: Diptera, zoogeography, biogeography, Canada, Norway, Svalbard.Les chironomides (moucherons non-piqueurs) sont parmi les animaux les plus abondants et diversifies dans les regions arctiques, mais des analyses detaillees des distributions de ces especes et de leur repartition biogeographique sont entravees par une taxonomie difficile et une dependance a la morphologie pour l'identification des especes. Ici, les auteurs tirent profit des donnees disponibles en matiere de codes a barres de l'ADN pour les chironomides arctiques au sein de la base de donnees BOLD pour analyser les similarites pour ce qui est des distributions des especes au long d'un gradient nordique Nearctique-Palearctique occidental. Au moyen de plus de 260 000 codes a barres representant 4666 BIN (<< Barcode Index Numbers >>) et 826 especes nommees (dont certaines de maniere interimaire) a partir d'une combinaison de donnees publiques et inedites, les auteurs montrent que la faune des chironomides du Groenland montre des ressemblances a la fois avec celles des regions Nearctique et Palearctique occidentale. Bien que des decomptes bruts indiquent une grande affinite Groenland--Amerique du Nord, des comparaisons a l'aide de l'indice de dissimilarite de Chao suggerent une similarite legerement plus elevee entre les communautes du Groenland et du Palearctique occidental. Les resultats etaient relativement coherents en faisant appel a diverses definitions des unites taxonomiques specifiques, incluant les especes definies sur une base morphologique, des BIN et des superBIN a un seuil de 4,5%. Bien que la plupart des taxons du Groenland soient partages avec au moins une autre region, ce qui reflete une distribution circum-arctique, les resultats revelent aussi que le Groenland recele une petite biodiversite endemique. Cette etude exploratoire demontre comment les efforts en matiere de codage a barres au moyen de regions geniques standardisees contribuent a la comprehension de la biogeographie a grande echelle en rendant possible l'analyse conjointe de donnees moleculaires publiques derivees de diverses etudes anterieures. [Traduit par la Redaction]Mots-cles: Diptera, zoogeographie, biogeographie, Canada, Norvege, Svalbard.

Author(s): R. Bintanja [sup.1] , F. M. Selten [sup.1] Author Affiliations: (1) Royal Netherlands Meteorological Institute (KNMI), Utrechtseweg 297, 3731GA, De Bilt, The Netherlands, Main Even though the moisture content [...], Precipitation is expected to increase far more over the twenty-first century in the Arctic than the global average; climate models show that this is driven mainly by increased local evaporation and sea-ice retreat, rather than by increased moisture transport from lower latitudes. Receding sea ice enhances surface evaporation Arctic precipitation is expected to increase by more than the global average during the twenty-first century. This trend has been attributed primarily to increased poleward moisture transport from lower latitudes. Now, Richard Bintanja and Frank Selten use climate models to suggest that in fact, the higher precipitation is driven by increased local evaporation, which is in turn linked to decreases in Arctic sea ice and general Arctic warming. Although tentative at this point, the results may have implications for the rate of sea-level rise and the strength of ocean circulation. Precipitation changes projected for the end of the twenty-first century show an increase of more than 50 per cent in the Arctic regions.sup.1,2. This marked increase, which is among the highest globally, has previously been attributed primarily to enhanced poleward moisture transport from lower latitudes.sup.3,4. Here we use state-of-the-art global climate models.sup.5 to show that the projected increases in Arctic precipitation over the twenty-first century, which peak in late autumn and winter, are instead due mainly to strongly intensified local surface evaporation (maximum in winter), and only to a lesser degree due to enhanced moisture inflow from lower latitudes (maximum in late summer and autumn). Moreover, we show that the enhanced surface evaporation results mainly from retreating winter sea ice, signalling an amplified Arctic hydrological cycle. This demonstrates that increases in Arctic precipitation are firmly linked to Arctic warming and sea-ice decline. As a result, the Arctic mean precipitation sensitivity (4.5 per cent increase per degree of temperature warming) is much larger than the global value (1.6 to 1.9 per cent per kelvin). The associated seasonally varying increase in Arctic precipitation is likely to increase river discharge.sup.6,7,8 and snowfall over ice sheets.sup.9 (thereby affecting global sea level), and could even affect global climate through freshening of the Arctic Ocean and subsequent modulations of the Atlantic meridional overturning circulation.sup.10,11.

Author Affiliations: An Arctic iceberg. Rising air temperatures are contributing to the growing incidence of marine heatwaves in the region. Credit: Felipe Dana/AP/Shutterstock A single Iceberg floats as the sun [...], Arctic waters have notched a growing number of extreme events called marine heatwaves, raising fears for the region&apos;s more heat-sensitive sea creatures. Arctic waters have notched a growing number of extreme events called marine heatwaves, raising fears for the region&apos;s more heat-sensitive sea creatures.

It can be argued that Arctic vegetation during the proximal Quaternary (the last circa 50 kyr) is less well understood than the ecology and population dynamics of the mammals that [...], Although it is generally agreed that the Arctic flora is among the youngest and least diverse on Earth, the processes that shaped it are poorly understood. Here we present 50 thousand years (kyr) of Arctic vegetation history, derived from the first large-scale ancient DNA metabarcoding study of circumpolar plant diversity. For this interval we also explore nematode diversity as a proxy for modelling vegetation cover and soil quality, and diets of herbivorous megafaunal mammals, many of which became extinct around 10 kyr bp (before present). For much of the period investigated, Arctic vegetation consisted of dry steppe-tundra dominated by forbs (non-graminoid herbaceous vascular plants). During the Last Glacial Maximum (25-15 kyr BP), diversity declined markedly, although forbs remained dominant. Much changed after 10 kyr BP, with the appearance of moist tundra dominated by woody plants and graminoids. Our analyses indicate that both graminoids and forbs would have featured in megafaunal diets. As such, our findings question the predominance of a Late Quaternary graminoid-dominated Arctic mammoth steppe.

The Arctic provides a test bed to understand and evaluate the consequences of threshold changes in regional system dynamics. Over the past several decades, the Arctic has warmed strongly in [...], A major challenge in predicting Earth's future climate state is to understand feedbacks that alter greenhouse-gas forcing. Here we synthesize field data from arctic Alaska, showing that terrestrial changes in summer albedo contribute substantially to recent high-latitude warming trends. Pronounced terrestrial summer warming in arctic Alaska correlates with a lengthening of the snow-free season that has increased atmospheric heating locally by about 3 watts per square meter per decade (similar in magnitude to the regional heating expected over multiple decades from a doubling of atmospheric C[O.sub.2]). The continuation of current trends in shrub and tree expansion could further amplify this atmospheric heating by two to seven times.

ABSTRACT. Historical relationships between people and a changing Arctic environment (which constitute a social-ecological system, or SES) can offer insights for management that promote both social and ecological resilience. The [...]

Robert E. Nelson (1) ABSTRACT. Some 56 species of Carabidae have been previously reported on the Arctic Slope of Alaska; of these, only nine have been found at coastal sites [...]

Hans Meltofte (1) ABSTRACT. There is increasing evidence that breeding wader censuses often have significantly underestimated densities in the Arctic and other areas. This evidence includes the recording of many [...]

(Received 7 April 1999; accepted in revised form 15 September 2000) ABSTRACT. In recent years, increasing scientific attention has been paid to sea mammals as biological indicators of Arctic environmental [...]

(Received 13 April 1999; accepted in revised form 25 April 2000) ABSTRACT. Changes according to elevation in frequencies of naturally stranded bowhead whale (Balaena mysticetus) remains on Holocene beaches in [...]

Research | Policy | Events | People | Awards | Business | Trend watch | Coming up RESEARCH Lightning records The World Meteorological Organization (WMO) has recognized two world records [...]

HOME is an icebreaker--at least for a few of us frozen into the Arctic Ocean aboard the Canadiar Coast Guard ship Des Groseilliers. We are here as an ancillary part [...]

Impacts of climate change were simulated over five summer seasons in a high arctic polar semi-desert at Ny Alesund, Svalbard, by using polythene tents to increase temperature, and by increasing precipitation and soil nutrient (NPK) availability. The effects of these treatments on vegetation cover were assessed at the start of the 1991, 1993, and 1995 field seasons, and at peak biomass in the same years. Over the first season of the experiment (1991), changes in percentage total living vegetation cover were significantly greater, and changes in dead vegetation cover significantly lower, in the tented treatments. In subsequent seasons, changes in total living cover were also greater under treatments simulating climate change, although the significant factors and interactions were year-specific. Between years, at both the early and mid-season sampling periods, the fertilizer application had the strongest effect on changes in plant cover, significantly decreasing cover of living Dryas octopetala, Saxifraga oppositifolia, and bare ground between 1991 and 1995, while increasing cover of bryophytes, Salix polaris, Polygonum viviparum, and total dead vegetation. Although cover of D. octopetala was greater during the first three years of fertilizer addition, marked winter injury occurred in this species on fertilized plots during winter 1993-1994. This resulted in reductions in total live cover and D. octopetala cover and an increase in total dead cover (by up to 22%) in watered and fertilized plots between 1991 and 1995. Seedlings of nitrophilous 'immigrant' species were established naturally on bare ground in fertilized plots in the third year of the study and subsequently increased in number, so that after five seasons the community tended more toward bird-cliff vegetation rather than polar semi-desert vegetation. The tent treatment and the simulated increase in summer precipitation had little effect between seasons on the plant community, in comparison with the fertilizer treatment. Key words: bare ground; colonization; extreme events; nitrogen; phosphorus; polar semi-desert; potassium; precipitation; temperature; tundra soils., INTRODUCTION General Circulation Models (GCMs) of the Earth's climate system predict profound changes in the abiotic environment of high-latitude ecosystems (Cattle and Crossley 1995). These include a mean temperature increase [...]

(Received 13 July 1995; accepted in revised form 19 June 1996) ABSTRACT. A sequence of phenomena links anthropogenic changes in the timing of freshwater runoff in Hudson Bay to a [...]

Field manipulations of light, temperature, nutrients, and length of growing season in directions simulating global environmental change altered biomass of the four most abundant vascular plant species in tussock tundra of northern Alaska. These species are Betula nana, Ledum palustre, Vaccinium vitis-idaea, and Eriophorum vaginatum. Biomass response to our treatments reflected changes in both growth and mortality, with growth being stimulated by treatments that enhanced biomass, and mortality being enhanced by all treatments (except in Vaccinium). Those species with highest leaf and stem turnover (the graminoid and deciduous shrub) initially showed large positive responses to nutrient addition. By contrast, slow-turnover evergreen species showed little initial change in production in response to our manipulations, and their long-term biomass responses were in the opposite direction to those of the responsive species. Short-term measurements of leaf expansion, photosynthesis, and phosphate uptake showed little correlation with net production or biomass change in response to manipulations because of compensatory mechanisms at levels of growth and allocation. Changes in nutrient distribution among species accounted for many of the long-term changes in biomass and productivity. Processes that are readily integrated at annual time steps (e.g., shoot growth, shoot mortality, allocation) were more useful than instantaneous physiological measurements in predicting decadal vegetation changes because (1) compensating responses among physiological processes buffer plant responses at progressively longer time scales, (2) species interactions in the community buffer ecosystem processes such as productivity and nutrient cycling from changes in growth of individual species, and (3) different time lags between physiological, demographic, and ecosystem processes complicate modeling of long-term responses from short-term mechanisms. Key words: arctic; climatic change; light; nutrients; phenology; photosynthesis; productivity; temperature; tundra., INTRODUCTION Physiological ecologists confronted with the challenge of predicting the role of terrestrial ecosystems in global processes (Houghton et al. 1990) have sought to provide a mechanistic understanding of the [...]

The nature of the Arctic polar stratosphere is observed to be similar in many respects to that of the Antartic polar stratosphere, where an ozone hole has been identified. Most [...]

Acting editor for ARCTIC. From August to November, Senior Research Associate and Editorial Advisor Peter Schledermann assumed the editorial duties for the journal while editor Karen McCullough was absent on [...]

M.P. HEIDE-JORGENSEN [1,2] N. HAMMEKEN [1] R. DIETZ [3] J. ORR [4] P.R. RICHARD [4] (Received 21 January 2000; accepted in revised form 28 November 2000) ABSTRACT. Time spent at [...]

THIRTY YEARS AGO, at a meeting devoted to finding new directions for Arctic biological oceanography, it was suggested that marine mammals might someday be used as 'educated' oceanographic sampling platforms. [...]

DAVID G. BARBER [1,2] ERIC SACZUK [1] PIERRE R. RICHARD [3] (Received 19 November 1999; accepted in revised form 27 September 2000) ABSTRACT. The spatial and temporal relationships between belugas [...]

D.J. ST. AUBIN [1] S. DEGUISE [2] P.R. RICHARD [3] T.G. SMITH [4] J.R. GERACI [5] (Received 31 January 2000; accepted in revised form 10 August 2000) ABSTRACT. The capture [...]

P.R. RICHARD [1] A.R. MARTIN [2] J.R. ORR [1] (Received 18 November 1999; accepted in revised form 30 May 2000) ABSTRACT. Beluga whales of the eastern Beaufort Sea stock were [...]

A.R. MARTIN [1] P. HALL [2] P.R. RICHARD [2] (Received 11 April 2000; accepted in revised form 23 October 2000) ABSTRACT. Beluga diving was studied in western Hudson Bay, where [...]

JACK R. ORR [1] RICKY JOE [2] DAVIDEE EVIC [3] (Received 18 November 1999; accepted in revised form 24 October 2000) ABSTRACT. For many decades, humans have captured white whales [...]

R. DIETZ [1,2] M.P. HEIDE-JORGENSEN [3] P.R. RICHARD [4] M. ACQUARONE [1] (Received 1 February 2000; accepted in revised form 2 November 2000) ABSTRACT. Ten narwhals (Monodon monoceros) were instrumented [...]

MICHAEL C.S. KINGSLE [1,2] SERGE GOSSELIN [1,3] GRY A. SLENO [1,4] (Received 18 November 1999; accepted in revised form 16 November 2000) INTRODUCTION ABSTRACT. Three adult and three juvenile belugas [...]

P.R. RICHARD [1] M.P. HEIDE-JORGENSEN [2] J.R. ORR [1] R. DIETZ [3] T.G. SMITH [4] (Received 18 November 1999; accepted in revised form 25 January 2001) ABSTRACT. Twenty-one adult belugas [...]

ROBERT S. SUYDAM [1] LLOYD F. LOWRY [2] KATHY J. FROST [2] GREG M. O'CORRY-CROWE [3] DANNY PIKOK Jr. [4] (Received 25 November 1999; accepted in revised form 10 February [...]

Cretaceous Cold-Seep Communities and Methane-Derived Carbonates in the Canadian Arctic IN RECENT YEARS, CHEMOSYNTHETIC benthic communities (life oases) resembling hydrothermal vent-taxa but associated with cold hydrocarbon and brine seeps have [...]

INTRODUCTION THE impacts of future climate change are expected to be felt earliest and most keenly at Arctic latitudes (Maxwell, 1997). Significant environmental changes observed in the last decade, such [...]

Distribution of and Feeding by the Copepod Pseudocalanus Under Fast Ice During the Arctic Spring LANDFAST SEA ICE INHIBITS PRImary production in the water column in the Canadian Arctic Archipelago [...]