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1
Shiryaev, A. G., and L. G. Mikhalyova. "Aphyllophoraceous fungi (Basidiomycetes) in the tundra and forest-tundra of the Lena River delta and Novosibirsk Islands (Arctic Yakutia)." Novosti sistematiki nizshikh rastenii 47 (2013): 155–66. http://dx.doi.org/10.31111/nsnr/2013.47.155.
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Total of 124 species of the aphyllophoroid fungi have been found in the tundra and forest-tundra vicinities of Tiksi and Novosibirsk Isles (Arctic Yakutia). Only 6 species were collected in native conditions of «high Arctic» (northern Arctic tundras), 5 of them belonging to the clavarioid morphological group (83.3 %). The species composition of aphyllophoroid fungi in other subzones of tuntra («low Arctic») is presented in our collections by 46 species, including 56 % of clavarioid and 37 % of corticioid species, poroid and thelephoroid morphological groups making less than 5 % both. 114 species were found in the forest-tundra zone, half of them are corticoid fungi (49 %), whereas the ratio of clavarioid ones is 27 %, that of poroid ones 22 %, and that of thelephoroid ones not over 2 % of species. Similar tendencies in changing the roles of different morphological groups under zonal gradient were described during analysis of the Urals and Mid-European aphyllophoroid fungi too.
2
Horak, E., and O. K. Miller Jr. "Phaeogalera and Galerina in arctic-subarctic Alaska (U.S.A.) and the Yukon Territory (Canada)." Canadian Journal of Botany 70, no. 2 (February 1, 1992): 414–33. http://dx.doi.org/10.1139/b92-055.
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Eleven taxa of Galerina and Phaeogalera are described. Galerina leptocystis, Galerina subarctica, and Galerina praticola are reported from arctic North America for the first time. Phaeogalra stagnina is only found in very humid, wet meadow tundra associated with Drepanocladus or Calliergon. Galerina arctica is reported for the first time from Alaska and Canada. One species, Galerina pseudocerina, is found only in arctic alpine habitats in Canada and not in the arctic tundra. Two forms of Galerina pseudomycenopsis represent the most common taxon observed in Alaskan North Slope wet meadow tundra on peat or associated with Calliergon, Drepanocladus, and Sphagnum. Two species, Galerina clavata and Galerina hypnorum, are common cosmopolitan taxa, but only G. clavata is frequently encountered on the Alaskan North Slope. The association of the Galerina taxa with mosses is presented and discussed, as well as their occurrence in microhabitats in wet meadow tundra and among polygons in coastal tundra on the Alaskan North Slope. Key words: Galerina, Phaeogalera, Cortinariaceae, Alaska, Yukon Territory, bryophytes.
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Christensen, Torben R. "Methane emission from Arctic tundra." Biogeochemistry 21, no. 2 (June 1993): 117–39. http://dx.doi.org/10.1007/bf00000874.
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Jiang, Fan, Xia Qiu, Xulu Chang, Zhihao Qu, Lvzhi Ren, Wenjing Kan, Youhao Guo, Chengxiang Fang, and Fang Peng. "Terrimonas arctica sp. nov., isolated from Arctic tundra soil." International Journal of Systematic and Evolutionary Microbiology 64, Pt_11 (November 1, 2014): 3798–803. http://dx.doi.org/10.1099/ijs.0.067033-0.
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A novel, Gram-stain-negative, aerobic, non-motile and rod-shaped bacterium, designated R9-86T, was isolated from tundra soil collected near Ny-Ålesund, Svalbard Archipelago, Norway (78° N). Growth occurred at 4–28 °C (optimum, 22–25 °C) and at pH 6.0–9.0 (optimum, pH 7.0). Flexirubin-type pigments were absent. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain R9-86T belonged to the genus Terrimonas in the family Chitinophagaceae . 16S rRNA gene sequence similarities between strain R9-86T and the type strains of species of the genus Terrimonas with validly published names ranged from 93.7 to 95.0 %. Strain R9-86T contained iso-C15 : 1-G (25.7 %), iso-C15 : 0 (24.5 %), iso-C17 : 0-3OH (18.3 %) and summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c, 8.7 %) as its major cellular fatty acids; phosphatidylethanolamine and an unknown polar lipid as its main polar lipids, and MK-7 as its predominant respiratory quinone. The DNA G+C content was 48.4 mol%. On the basis of phenotypic, chemotaxonomic and phylogenetic data, strain R9-86T is considered to represent a novel species of the genus Terrimonas , for which the name Terrimonas arctica sp. nov. is proposed. The type strain is R9-86T ( = CCTCC AB 2011004T = NRRL B-59114T).
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Jiang, Fan, Jun Dai, Yang Wang, Xiuqing Xue, Mengbo Xu, Wenxin Li, Chengxiang Fang, and Fang Peng. "Cohnella arctica sp. nov., isolated from Arctic tundra soil." International Journal of Systematic and Evolutionary Microbiology 62, Pt_4 (April 1, 2012): 817–21. http://dx.doi.org/10.1099/ijs.0.030247-0.
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A psychrotolerant Gram-reaction-negative, rod-shaped and orange-pigmented bacterium, designated strain M9-62T, which was motile by means of peritrichous flagella, was isolated from tundra soil sampled near Ny-Ålesund, Svalbard Islands, Norway (78° N). Growth occurred at 4–30 °C (optimum, 25 °C) and pH 5.0–8.0 (optimum, pH 6.0–7.0). Analysis of the 16S rRNA gene sequence of strain M9-62T placed it in the genus Cohnella ; sequence similarities of the isolate with type strains of members of related genera ranged from 92.0 to 96.3 %. Strain M9-62T contained anteiso-C15 : 0 (51.1 %), iso-C16 : 0 (7.5 %) and C16 : 0 (6.1 %) as the major cellular fatty acids and diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and lysyl-phosphatidylglycerol as the main polar lipids. The major respiratory quinone was MK-7 and the DNA G+C content was 50.3 mol%. On the basis of phenotypic, chemotaxonomic and phylogenetic data, strain M9-62T is considered to represent a novel species of the genus Cohnella , for which the name Cohnella arctica sp. nov. is proposed; the type strain is M9-62T ( = CCTCC AB 2010228T = NRRL B-59459T).
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Xu, Qiang, Fan Jiang, Xuyang Da, Yumin Zhang, Yingchao Geng, Kun Qin, Jia Liu, and Fang Peng. "Chitinimonas arctica sp. nov., isolated from Arctic tundra soil." International Journal of Systematic and Evolutionary Microbiology 70, no. 5 (May 1, 2020): 3455–61. http://dx.doi.org/10.1099/ijsem.0.004194.
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A Gram-stain-negative, rod-shaped, green-pigmented, aerobic and motile bacterium, strain R3-44T, was isolated from Arctic tundra soil. Stain R3-44T clustered closely with members of the genus Chitinimonas , which belongs to the family Burkholderiaceae , and showed the highest 16S rRNA sequence similarity to Chitinimonas naiadis AR2T (96.10%). Strain R3-44T grew optimally at pH 7.0, 28 °C and in the presence of 0–0.5 % (w/v) NaCl. The predominant respiratory isoprenoid quinone of strain R3-44T was identified as ubiquinone Q-8. The polar lipids consisted of phosphatidylglycerol, phosphatidylethanolamine, unidentified aminolipid and unidentified phospholipid. The main fatty acids were summed feature 3 (comprising C16 : 1 ω7c and/or C16 : 1 ω6c, 40.6 %) and C16 : 0 (29.3 %). The DNA G+C content of strain R3-44T was 60.8 mol%. On the basis of the evidence presented in this study, strain R3-44T represents a novel species of the genus Chitinimonas , for which the name Chitinimonas arctica sp. nov. is proposed, with the type strain R3-44T (=CCTCC AB 2010422T=KCTC 72602T).
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Fu, Dongjie, Fenzhen Su, Juan Wang, and Yijie Sui. "Patterns of Arctic Tundra Greenness Based on Spatially Downscaled Solar-Induced Fluorescence." Remote Sensing 11, no. 12 (June 20, 2019): 1460. http://dx.doi.org/10.3390/rs11121460.
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A general greening trend in the Arctic tundra biome has been indicated by satellite remote sensing data over recent decades. However, since 2011, there have been signs of browning trends in many parts of the region. Previous research on tundra greenness across the Arctic region has relied on the satellite-derived normalized difference vegetation index (NDVI). In this research, we initially used spatially downscaled solar-induced fluorescence (SIF) data to analyze the spatiotemporal variation of Arctic tundra greenness (2007–2013). The results derived from the SIF data were also compared with those from two NDVIs (the Global Inventory Modeling and Mapping Studies NDVI3g and MOD13Q1 NDVI), and the eddy-covariance (EC) observed gross primary production (GPP). It was found that most parts of the Arctic tundra below 75° N were browning (–0.0098 mW/m2/sr/nm/year, where sr is steradian and nm is nanometer) using SIF, whereas spatially and temporally heterogeneous trends (greening or browning) were obtained based on the two NDVI products. This research has further demonstrated that SIF data can provide an alternative direct proxy for Arctic tundra greenness.
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Christensen, Torben. "Arctic and sub-Arctic soil emissions: possible implications for global climate change." Polar Record 27, no. 162 (July 1991): 205–10. http://dx.doi.org/10.1017/s0032247400012584.
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AbstractClimate models predict a substantial warming at high latitudes following the enhanced greenhouse effect caused by anthropogenic emissions of carbon dioxide (CO2), methane (CH4), and various other trace gases. Arctic and sub-Arctic soils contain large amounts of organic carbon that could be made increasingly available for decomposition in a wanner climate due to deepening of the biologically-active layer and increased thermokarst erosion. This produces the potential for increased emissions of CO2 and CH4 from tundra areas and thus positive (enhancing) feedback effects on the greenhouse effect. From being a net absorber of CO2 the global tundra areas could become a net source of up to 1.25 Gt C yr1 as a result of the predicted warmer and dryer conditions during the thaw period. CH4 is at least 21 times more effective as a greenhouse gas than CO2. How the CH4 balance in the tundra will respond to climate change is therefore very important but also much less certain. Estimates of total present CH4 emissions from northern wetlands vary greatly, ranging from 2.4 to 106 Tg CH4 yr1 and little is known about the mechanisms controlling the flux. There are indications, however, that if the tundra becomes wetter under warming, CH4 emissions would probably increase. If it becomes dryer, the emissions could cease or even turn the tundra into a sink for atmospheric CH4, partly due to increasing microbial consumption of CH4 in the soil. There is an urgent need for more research into the processes controlling the CH4 flux in Arctic and sub-Arctic soils.
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Liu, Xue-Yan, Keisuke Koba, Lina A. Koyama, Sarah E. Hobbie, Marissa S. Weiss, Yoshiyuki Inagaki, Gaius R. Shaver, et al. "Nitrate is an important nitrogen source for Arctic tundra plants." Proceedings of the National Academy of Sciences 115, no. 13 (March 14, 2018): 3398–403. http://dx.doi.org/10.1073/pnas.1715382115.
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Plant nitrogen (N) use is a key component of the N cycle in terrestrial ecosystems. The supply of N to plants affects community species composition and ecosystem processes such as photosynthesis and carbon (C) accumulation. However, the availabilities and relative importance of different N forms to plants are not well understood. While nitrate (NO3−) is a major N form used by plants worldwide, it is discounted as a N source for Arctic tundra plants because of extremely low NO3− concentrations in Arctic tundra soils, undetectable soil nitrification, and plant-tissue NO3− that is typically below detection limits. Here we reexamine NO3− use by tundra plants using a sensitive denitrifier method to analyze plant-tissue NO3−. Soil-derived NO3− was detected in tundra plant tissues, and tundra plants took up soil NO3− at comparable rates to plants from relatively NO3−-rich ecosystems in other biomes. Nitrate assimilation determined by 15N enrichments of leaf NO3− relative to soil NO3− accounted for 4 to 52% (as estimated by a Bayesian isotope-mixing model) of species-specific total leaf N of Alaskan tundra plants. Our finding that in situ soil NO3− availability for tundra plants is high has important implications for Arctic ecosystems, not only in determining species compositions, but also in determining the loss of N from soils via leaching and denitrification. Plant N uptake and soil N losses can strongly influence C uptake and accumulation in tundra soils. Accordingly, this evidence of NO3− availability in tundra soils is crucial for predicting C storage in tundra.
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Mbufong, H. N., M. Lund, M. Aurela, T. R. Christensen, W. Eugster, T. Friborg, B. U. Hansen, et al. "Assessing the spatial variability in peak season CO<sub>2</sub> exchange characteristics across the Arctic tundra using a light response curve parameterization." Biogeosciences Discussions 11, no. 5 (May 6, 2014): 6419–60. http://dx.doi.org/10.5194/bgd-11-6419-2014.
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Abstract. This paper aims to assess the functional and spatial variability in the response of CO2 exchange to irradiance across the Arctic tundra during peak season using light response curve (LRC) parameters. This investigation allows us to better understand the future response of Arctic tundra under climatic change. Data was collected using the micrometeorological eddy covariance technique from 12 circumpolar Arctic tundra sites, in the range of 64–74° N. The LRCs were generated for 14 days with peak net ecosystem exchange (NEE) using an NEE -irradiance model. Parameters from LRCs represent site specific traits and characteristics describing: (a) NEE at light saturation (Fcsat), (b) dark respiration (Rd), (c) light use efficiency (α), (d) NEE when light is at 1000 μmol m−2 s−1 (Fc1000), (e) potential photosynthesis at light saturation (Psat) and (f) the light compensation point (LCP). Parameterization of LRCs was successful in predicting CO2 flux dynamics across the Arctic tundra. Yet we did not find any trends in LRC parameters across the whole Arctic tundra but there were indications for temperature and latitudinal differences within sub-regions like Russia and Greenland. Together, LAI and July temperature had a high explanatory power of the variance in assimilation parameters (Fcsat, Fc1000 and Psat), thus illustrating the potential for upscaling CO2 exchange for the whole Arctic tundra. Dark respiration was more variable and less correlated to environmental drivers than was assimilation parameters. Thus, indicating the inherent need to include other parameters such as nutrient availability, substrate quantity and quality in flux monitoring activities.
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Conn, Jeffery S., Christina Behr-Andres, Janice Wiegers, Ed Meggert, and Nick Glover. "Remediation of Arctic tundra following petroleum or salt water spills." Polar Record 37, no. 202 (July 2001): 264–66. http://dx.doi.org/10.1017/s0032247400027297.
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AbstractOil exploration and production in the Arctic regions has resulted in spills of petroleum and salt water in tundra ecosystems. The transportation and use of refined petroleum in Arctic regions has also led to spills, and the cleanup and ecosystem restoration in these systems can often be complicated by the existence of ice-rich soil permafrost. Compaction, removal, or tearing of the protective vegetation and organic soil can result in thermokarsting and associated changes in plant communities, which may persist for decades. Such problems led the State of Alaska to establish recovery-based clean-up regulations for spills to tundra.A review was conducted of published literature, government agency spill files, and industry reports concerning spills of petroleum and saline water in tundra regions. A tundra spill database was created, which allows the determination of the spill frequency of refined petroleum, crude oil, and saline water. Refined-petroleum spills are more common and smaller than crude-oil and saline-water spills. Most spills are to wet tundra during winter, and winter spills are more effectively cleaned up than those in summer. In winter, snow contains most spills, frozen soil and frozen water bodies prevent much soil penetration, plants are dormant, and operation of heavy equipment is feasible on frozen ground. The use of fire to reduce the volume of petroleum spills in winter is not recommended. Heat from burning petroleum can melt snow, thaw soil, and allow the penetration of petroleum into soil.
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McGuire, A. D., T. R. Christensen, D. Hayes, A. Heroult, E. Euskirchen, Y. Yi, J. S. Kimball, et al. "An assessment of the carbon balance of arctic tundra: comparisons among observations, process models, and atmospheric inversions." Biogeosciences Discussions 9, no. 4 (April 17, 2012): 4543–94. http://dx.doi.org/10.5194/bgd-9-4543-2012.
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Abstract. Although arctic tundra has been estimated to cover only 8% of the global land surface, the large and potentially labile carbon pools currently stored in tundra soils have the potential for large emissions of carbon (C) under a warming climate. These emissions as radiatively active greenhouse gases in the form of both CO2 and CH4 could amplify global warming. Given the potential sensitivity of these ecosystems to climate change and the expectation that the Arctic will experience appreciable warming over the next century, it is important to assess whether responses of C exchange in tundra regions are likely to enhance or mitigate warming. In this study we compared analyses of C exchange of Arctic tundra between 1990–1999 and 2000–2006 among observations, regional and global applications of process-based terrestrial biosphere models, and atmospheric inversion models. Syntheses of the compilation of flux observations and of inversion model results indicate that the annual exchange of CO2 between arctic tundra and the atmosphere has large uncertainties that cannot be distinguished from neutral balance. The mean estimate from an ensemble of process-based model simulations suggests that arctic tundra acted as a sink for atmospheric CO2 in recent decades, but based on the uncertainty estimates it cannot be determined with confidence whether these ecosystems represent a weak or a strong sink. Tundra was 0.6 °C warmer in the 2000s compared to the 1990s. The central estimates of the observations, process-based models, and inversion models each identify stronger sinks in the 2000s compared with the 1990s. Similarly, the observations and the applications of regional process-based models suggest that CH4 emissions from arctic tundra have increased from the 1990s to 2000s. Based on our analyses of the estimates from observations, process-based models, and inversion models, we estimate that arctic tundra was a sink for atmospheric CO2 of 110 Tg C yr−1 (uncertainty between a sink of 291 Tg C yr−1 and a source of 80 Tg C yr−1) and a source of CH4 to the atmosphere of 19 Tg C yr−1 (uncertainty between sources of 8 and 29 Tg C yr−1). The suite of analyses conducted in this study indicate that it is clearly important to reduce uncertainties in the observations, process-based models, and inversions in order to better understand the degree to which Arctic tundra is influencing atmospheric CO2 and CH4 concentrations. The reduction of uncertainties can be accomplished through (1) the strategic placement of more CO2 and CH4 monitoring stations to reduce uncertainties in inversions, (2) improved observation networks of ground-based measurements of CO2 and CH4 exchange to understand exchange in response to disturbance and across gradients of hydrological variability, and (3) the effective transfer of information from enhanced observation networks into process-based models to improve the simulation of CO2 and CH4 exchange from arctic tundra to the atmosphere.
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Mbufong, H. N., M. Lund, M. Aurela, T. R. Christensen, W. Eugster, T. Friborg, B. U. Hansen, et al. "Assessing the spatial variability in peak season CO<sub>2</sub> exchange characteristics across the Arctic tundra using a light response curve parameterization." Biogeosciences 11, no. 17 (September 15, 2014): 4897–912. http://dx.doi.org/10.5194/bg-11-4897-2014.
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Abstract. This paper aims to assess the spatial variability in the response of CO2 exchange to irradiance across the Arctic tundra during peak season using light response curve (LRC) parameters. This investigation allows us to better understand the future response of Arctic tundra under climatic change. Peak season data were collected during different years (between 1998 and 2010) using the micrometeorological eddy covariance technique from 12 circumpolar Arctic tundra sites, in the range of 64–74° N. The LRCs were generated for 14 days with peak net ecosystem exchange (NEE) using an NEE–irradiance model. Parameters from LRCs represent site-specific traits and characteristics describing the following: (a) NEE at light saturation (Fcsat), (b) dark respiration (Rd), (c) light use efficiency (α), (d) NEE when light is at 1000 μmol m−2 s−1 (Fc1000), (e) potential photosynthesis at light saturation (Psat) and (f) the light compensation point (LCP). Parameterization of LRCs was successful in predicting CO2 flux dynamics across the Arctic tundra. We did not find any trends in LRC parameters across the whole Arctic tundra but there were indications for temperature and latitudinal differences within sub-regions like Russia and Greenland. Together, leaf area index (LAI) and July temperature had a high explanatory power of the variance in assimilation parameters (Fcsat, Fc1000 and Psat, thus illustrating the potential for upscaling CO2 exchange for the whole Arctic tundra. Dark respiration was more variable and less correlated to environmental drivers than were assimilation parameters. This indicates the inherent need to include other parameters such as nutrient availability, substrate quantity and quality in flux monitoring activities.
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Kuikka, Eeva. "Kuvitteellisia periferioita." Idäntutkimus 28, no. 1 (April 15, 2021): 50–65. http://dx.doi.org/10.33345/idantutkimus.107841.
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Artikkeli tarkastelee nenetsikirjailija Anna Nerkagin pienoisromaaneja Nogo-suvun Aniko (1976) ja Valkea jäkälä (1996) sekä venäläisen elokuvaohjaaja Vladimir Tumajevin näiden teosten pohjalta ohjaamaa elokuvaa Valkea jäkälä (2014). Lähestyn teoksia kysymällä, kuinka niissä kuvataan arktista tundraa tilana ja kuinka teoksissa kuvattu perifeerinen tila esitetään suhteessa valtakeskuksiin. Artikkelin tärkeimpinä teoreettisina viitekehyksinä toimivat geokritiikki sekä jälkikolonialistinen teoria. Nerkagin teoksissa tundra näyttäytyy muusta maasta irrallisena alkuperäiskansan toimintaympäristönä, joka kytkeytyy sekä nenetsien historiaan että näiden suhteeseen ei-inhimillisen luonnon kanssa. Erityisesti Valkean jäkälän voi nähdä myös kritisoivan yhteiskunnan tapaa laiminlyödä alueen asioiden hoitoa. Tumajevin elokuva puolestaan nojaa venäläisessä kulttuurissa vallitseviin käsityksiin arktisesta tundrasta ja heijastaa myös Venäjän 2000-luvulla aktivoitunutta tarvetta profiloitua arktisena suurvaltana.
Imagined Peripheries
Abstract: This article focuses on Nenets author Anna Nerkagi’s short novels Aniko of the Clan Nogo (1976) and The White Moss (1996) and their film adaptation The White Moss (2014) by Russian film director Vladimir Tumaev. I approach these works by asking how they depict the Arctic tundra as a space and how they describe the relationship between this peripheral space and the power centres. The main theoretical frameworks used are geocriticism and postcolonial theory. Nerkagi’s works depict the tundra as a region that is disconnected from the rest of the country and defined by Nenets history and the relationship with non-human nature. Especially in The White Moss, the reader can also notice a social critique of the neglect of the region. Tumaev’s film, on the other hand, relies on Russian cultural conceptions of the Arctic tundra and reflects Russia’s urge to be profiled as an Arctic superpower in the 2000s.
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McGuire, A. D., T. R. Christensen, D. Hayes, A. Heroult, E. Euskirchen, J. S. Kimball, C. Koven, et al. "An assessment of the carbon balance of Arctic tundra: comparisons among observations, process models, and atmospheric inversions." Biogeosciences 9, no. 8 (August 17, 2012): 3185–204. http://dx.doi.org/10.5194/bg-9-3185-2012.
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Abstract. Although Arctic tundra has been estimated to cover only 8% of the global land surface, the large and potentially labile carbon pools currently stored in tundra soils have the potential for large emissions of carbon (C) under a warming climate. These emissions as radiatively active greenhouse gases in the form of both CO2 and CH4 could amplify global warming. Given the potential sensitivity of these ecosystems to climate change and the expectation that the Arctic will experience appreciable warming over the next century, it is important to assess whether responses of C exchange in tundra regions are likely to enhance or mitigate warming. In this study we compared analyses of C exchange of Arctic tundra between 1990 and 2006 among observations, regional and global applications of process-based terrestrial biosphere models, and atmospheric inversion models. Syntheses of flux observations and inversion models indicate that the annual exchange of CO2 between Arctic tundra and the atmosphere has large uncertainties that cannot be distinguished from neutral balance. The mean estimate from an ensemble of process-based model simulations suggests that Arctic tundra has acted as a sink for atmospheric CO2 in recent decades, but based on the uncertainty estimates it cannot be determined with confidence whether these ecosystems represent a weak or a strong sink. Tundra was 0.6 °C warmer in the 2000s compared to the 1990s. The central estimates of the observations, process-based models, and inversion models each identify stronger sinks in the 2000s compared with the 1990s. Some of the process models indicate that this occurred because net primary production increased more in response to warming than heterotrophic respiration. Similarly, the observations and the applications of regional process-based models suggest that CH4 emissions from Arctic tundra have increased from the 1990s to 2000s because of the sensitivity of CH4 emissions to warmer temperatures. Based on our analyses of the estimates from observations, process-based models, and inversion models, we estimate that Arctic tundra was a sink for atmospheric CO2 of 110 Tg C yr−1 (uncertainty between a sink of 291 Tg C yr−1 and a source of 80 Tg C yr−1) and a source of CH4 to the atmosphere of 19 Tg C yr−1 (uncertainty between sources of 8 and 29 Tg C yr−1). The suite of analyses conducted in this study indicate that it is important to reduce uncertainties in the observations, process-based models, and inversions in order to better understand the degree to which Arctic tundra is influencing atmospheric CO2 and CH4 concentrations. The reduction of uncertainties can be accomplished through (1) the strategic placement of more CO2 and CH4 monitoring stations to reduce uncertainties in inversions, (2) improved observation networks of ground-based measurements of CO2 and CH4 exchange to understand exchange in response to disturbance and across gradients of climatic and hydrological variability, and (3) the effective transfer of information from enhanced observation networks into process-based models to improve the simulation of CO2 and CH4 exchange from Arctic tundra to the atmosphere.
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Lecomte, Nicolas, and Marie-Andrée Giroux. "New avian breeding records for Igloolik Island, Nunavut." Canadian Field-Naturalist 129, no. 2 (August 5, 2015): 194. http://dx.doi.org/10.22621/cfn.v129i2.1702.
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New breeding records for three tundra nesting species were documented on the Arctic island of Igloolik (Nunavut, Canada). The species are the Cackling Goose (Branta hutchinsii), the Tundra Swan (Cygnus columbianus), and the Pectoral Sandpiper (Calidris melanotos). These records refine their breeding range in the Canadian Arctic archipelago, while highlighting changes in detected bird communities at specific locations through time.
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Buchwal, Agata, Patrick F. Sullivan, Marc Macias-Fauria, Eric Post, Isla H. Myers-Smith, Julienne C. Stroeve, Daan Blok, et al. "Divergence of Arctic shrub growth associated with sea ice decline." Proceedings of the National Academy of Sciences 117, no. 52 (December 14, 2020): 33334–44. http://dx.doi.org/10.1073/pnas.2013311117.
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Arctic sea ice extent (SIE) is declining at an accelerating rate with a wide range of ecological consequences. However, determining sea ice effects on tundra vegetation remains a challenge. In this study, we examined the universality or lack thereof in tundra shrub growth responses to changes in SIE and summer climate across the Pan-Arctic, taking advantage of 23 tundra shrub-ring chronologies from 19 widely distributed sites (56°N to 83°N). We show a clear divergence in shrub growth responses to SIE that began in the mid-1990s, with 39% of the chronologies showing declines and 57% showing increases in radial growth (decreasers and increasers, respectively). Structural equation models revealed that declining SIE was associated with rising air temperature and precipitation for increasers and with increasingly dry conditions for decreasers. Decreasers tended to be from areas of the Arctic with lower summer precipitation and their growth decline was related to decreases in the standardized precipitation evapotranspiration index. Our findings suggest that moisture limitation, associated with declining SIE, might inhibit the positive effects of warming on shrub growth over a considerable part of the terrestrial Arctic, thereby complicating predictions of vegetation change and future tundra productivity.
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Yang, Dedi, Ran Meng, Bailey D. Morrison, Andrew McMahon, Wouter Hantson, Daniel J. Hayes, Amy L. Breen, Verity G. Salmon, and Shawn P. Serbin. "A Multi-Sensor Unoccupied Aerial System Improves Characterization of Vegetation Composition and Canopy Properties in the Arctic Tundra." Remote Sensing 12, no. 16 (August 15, 2020): 2638. http://dx.doi.org/10.3390/rs12162638.
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Changes in vegetation distribution, structure, and function can modify the canopy properties of terrestrial ecosystems, with potential consequences for regional and global climate feedbacks. In the Arctic, climate is warming twice as fast as compared to the global average (known as ‘Arctic amplification’), likely having stronger impacts on arctic tundra vegetation. In order to quantify these changes and assess their impacts on ecosystem structure and function, methods are needed to accurately characterize the canopy properties of tundra vegetation types. However, commonly used ground-based measurements are limited in spatial and temporal coverage, and differentiating low-lying tundra plant species is challenging with coarse-resolution satellite remote sensing. The collection and processing of multi-sensor data from unoccupied aerial systems (UASs) has the potential to fill the gap between ground-based and satellite observations. To address the critical need for such data in the Arctic, we developed a cost-effective multi-sensor UAS (the ‘Osprey’) using off-the-shelf instrumentation. The Osprey simultaneously produces high-resolution optical, thermal, and structural images, as well as collecting point-based hyperspectral measurements, over vegetation canopies. In this paper, we describe the setup and deployment of the Osprey system in the Arctic to a tundra study site located in the Seward Peninsula, Alaska. We present a case study demonstrating the processing and application of Osprey data products for characterizing the key biophysical properties of tundra vegetation canopies. In this study, plant functional types (PFTs) representative of arctic tundra ecosystems were mapped with an overall accuracy of 87.4%. The Osprey image products identified significant differences in canopy-scale greenness, canopy height, and surface temperature among PFTs, with deciduous low to tall shrubs having the lowest canopy temperatures while non-vascular lichens had the warmest. The analysis of our hyperspectral data showed that variation in the fractional cover of deciduous low to tall shrubs was effectively characterized by Osprey reflectance measurements across the range of visible to near-infrared wavelengths. Therefore, the development and deployment of the Osprey UAS, as a state-of-the-art methodology, has the potential to be widely used for characterizing tundra vegetation composition and canopy properties to improve our understanding of ecosystem dynamics in the Arctic, and to address scale issues between ground-based and airborne/satellite observations.
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Witharana, Chandi, Md Abul Ehsan Bhuiyan, Anna K. Liljedahl, Mikhail Kanevskiy, Torre Jorgenson, Benjamin M. Jones, Ronald Daanen, et al. "An Object-Based Approach for Mapping Tundra Ice-Wedge Polygon Troughs from Very High Spatial Resolution Optical Satellite Imagery." Remote Sensing 13, no. 4 (February 4, 2021): 558. http://dx.doi.org/10.3390/rs13040558.
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Very high spatial resolution commercial satellite imagery can inform observation, mapping, and documentation of micro-topographic transitions across large tundra regions. The bridging of fine-scale field studies with pan-Arctic system assessments has until now been constrained by a lack of overlap in spatial resolution and geographical coverage. This likely introduced biases in climate impacts on, and feedback from the Arctic region to the global climate system. The central objective of this exploratory study is to develop an object-based image analysis workflow to automatically extract ice-wedge polygon troughs from very high spatial resolution commercial satellite imagery. We employed a systematic experiment to understand the degree of interoperability of knowledge-based workflows across distinct tundra vegetation units—sedge tundra and tussock tundra—focusing on the same semantic class. In our multi-scale trough modelling workflow, we coupled mathematical morphological filtering with a segmentation process to enhance the quality of image object candidates and classification accuracies. Employment of the master ruleset on sedge tundra reported classification accuracies of correctness of 0.99, completeness of 0.87, and F1 score of 0.92. When the master ruleset was applied to tussock tundra without any adaptations, classification accuracies remained promising while reporting correctness of 0.87, completeness of 0.77, and an F1 score of 0.81. Overall, results suggest that the object-based image analysis-based trough modelling workflow exhibits substantial interoperability across the terrain while producing promising classification accuracies. From an Arctic earth science perspective, the mapped troughs combined with the ArcticDEM can allow hydrological assessments of lateral connectivity of the rapidly changing Arctic tundra landscape, and repeated mapping can allow us to track fine-scale changes across large regions and that has potentially major implications on larger riverine systems.
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Pereboom, Eleanor MB, Richard S. Vachula, Yongsong Huang, and James Russell. "The morphology of experimentally produced charcoal distinguishes fuel types in the Arctic tundra." Holocene 30, no. 7 (March 9, 2020): 1091–96. http://dx.doi.org/10.1177/0959683620908629.
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Wildfires in the Arctic tundra have become increasingly frequent in recent years and have important implications for tundra ecosystems and for the global carbon cycle. Lake sediment–based records are the primary means of understanding the climatic influences on tundra fires. Sedimentary charcoal has been used to infer climate-driven changes in tundra fire frequency but thus far cannot differentiate characteristics of the vegetation burnt during fire events. In forested ecosystems, charcoal morphologies have been used to distinguish changes in fuel type consumed by wildfires of the past; however, no such approach has been developed for tundra ecosystems. We show experimentally that charcoal morphologies can be used to differentiate graminoid (mean = 6.77; standard deviation (SD) = 0.23) and shrub (mean = 2.42; SD = 1.86) biomass burnt in tundra fire records. This study is a first step needed to construct more nuanced tundra wildfire histories and to understand how wildfire will impact the region as vegetation and fire change in the future.
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Melke, J., B. Witkowska-Walczak, and P. Bartmiński. "Water retention of arctic zone soils (Spitsbergen)." International Agrophysics 27, no. 4 (December 1, 2013): 439–44. http://dx.doi.org/10.2478/intag-2013-0014.
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Abstract The water retention characteristics of the arctic zone soils ((TurbicCryosol (Skeletic), TurbicCryosols (Siltic, Skeletic) and BrunicTurbicCryosol (Arenic)) derived in different micro-relief forms were determined. Water retention curves were similar in their course for the mud boils, cell forms, and sorted circles ie for TurbicCryosols. For these forms, the mud boils showed the highest water retention ability, whereas the sorted circles - the lowest one. Water retention curves for the tundra polygons (Brunic TurbicCryosol, Arenic) were substantially different from these mentioned above. The tundra polygons were characterized by the lowest bulk density of 1.26 g cm-3, whereas the sorted circles (TurbicCryosol, Skeletic) - the highest: 1.88 g cm-3. Total porosity was the highest for the tundra polygons (52.4 and 55.5%) and the lowest - for the sorted circles (28.8 and 26.2%). Pore size distribution of the investigated soils showed that independently of depths, the highest content of large and medium pores was noticed for the tundra polygons ie 21.2-24.2 and 19.9-18.7%, respectively. The lowest content of large pores was observed for the cell forms (6.4-5.9%) whereas the mud boils exhibited the lowest amount of medium sized pores (12.2-10.4%) (both TurbicCryosols Siltic, Skeletic). The highest content of small pores was detected in the mud boils - 20.4 and 19.0%.
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Rühland, Kathleen M., John P. Smol, and Reinhard Pienitz. "Ecology and spatial distributions of surface-sediment diatoms from 77 lakes in the subarctic Canadian treeline region." Canadian Journal of Botany 81, no. 1 (January 1, 2003): 57–73. http://dx.doi.org/10.1139/b03-005.
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Diatom ecology and species compositional patterns across current arctic treeline can provide important paleoecological information associated with climatic and environmental change. In this paper we examine the relationships between measured environmental variables and modern diatom assemblage composition from 77 lakes across the treeline ecozones of the Central Canadian Arctic. The weighted-average optima for selected environmental variables were calculated for 74 of the most common diatoms, and photographic plates of these taxa are included. Our results indicated that both forest-tundra and arctic tundra lakes differed significantly in diatom assemblage composition from boreal forest lakes. In general, planktonic diatom taxa (e.g., Cyclotella species) were more common in forested lakes, which may be due to ecological conditions related to climate. Small, benthic, alkaliphilic Fragilaria taxa reached their highest abundances in forested lakes, likely because of the more alkaline nature of these lakes. Arctic tundra lakes were characterized by higher abundances of circumneutral to acidophilic taxa. Heavily silicified Aulacoseira taxa (e.g., Aulacoseira lirata, Aulacoseira perglabra) were more common in deeper tundra lakes, likely because of the less alkaline nature of these lakes and greater wind-induced turbulence in this zone. These trends provide important information on the variability of aquatic ecosystems across this climatically sensitive vegetational gradient.Key words: arctic treeline, Canada, diatoms, paleolimnology, weighted-average optima, climate change.
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Shiryaev, A. G. "Spatial structure of clavarioid fungi biota in tundra zone of Taimyr Peninsula." Novosti sistematiki nizshikh rastenii 45 (2011): 133–45. http://dx.doi.org/10.31111/nsnr/2011.45.133.
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25 species of 8 genera of clavarioid fungi were found in the Taimyr tundras. The taxonomical structure of the studied biota is close to adjacent Yamal-Gydan and Arctic Jakutian biotas of clavarioid fungi. A group of active species was defined (Multiclavula corynoides, Typhula crassipes, T. culmigena, T. lutescens, T. variabilis). Spatial structure analysis has shown a significant difference between western and eastern Taimyr as well as between “high Arctic” (Arctic deserts and northern Arctic tundras) and “low Arctic” (southern Arctic tundras, northern and southern Hypoarctic tundras) biotas of clavarioid fungi.
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Owens, Edward H., and Jacqueline Michel. "Planning for Shoreline Response to Spills in Arctic Environments." International Oil Spill Conference Proceedings 2003, no. 1 (April 1, 2003): 591–96. http://dx.doi.org/10.7901/2169-3358-2003-1-591.
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ABSTRACT The Arctic coasts present three unique shoreline types that are common in North America and Eurasia, but that are not found in lower latitudes or in the southern hemisphere: tundra cliffs, peat shorelines, and inundated low-land tundra. Tundra cliffs range in character from ice-rich exposures that are dominated by rapid thermo-erosional processes to high (10–15 meters) sediment-rich cliffs that may be eroded by slumping or basal sapping. One product of this rapid erosion of the tundra is to produce large volumes of peat and in many sections these form the dominant shore-zone material. In low-lying areas the flooding of the tundra has produced extremely complex shoreline configurations characterized by the elevated rims of patterned ground. These unique arctic shore types present different sets of challenges for shoreline cleanup and treatment and have been included in the U.S. marine oil spill response guide published in 2001 by API, NOAA, USCG, and USEPA and several specialized Arctic response manuals published recently by Environment Canada. A low-altitude aerial videotape survey in 2001 produced continuous images of the mainland and barrier island coasts of the Alaskan Beaufort and Chukchi Sea coasts from the Canadian border to Point Hope, used to map the shore types as part of a mapping project for the Minerals Management Service. The mapping revealed that the three arctic shoreline types are present on more than half (54 per cent) of the coast between the Canadian border and Point Hope.
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Chipman, M. L., V. Hudspith, P. E. Higuera, P. A. Duffy, R. Kelly, W. W. Oswald, and F. S. Hu. "Spatiotemporal patterns of tundra fires: late-Quaternary charcoal records from Alaska." Biogeosciences 12, no. 13 (July 3, 2015): 4017–27. http://dx.doi.org/10.5194/bg-12-4017-2015.
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Abstract. Anthropogenic climate change has altered many ecosystem processes in the Arctic tundra and may have resulted in unprecedented fire activity. Evaluating the significance of recent fires requires knowledge from the paleofire record because observational data in the Arctic span only several decades, much shorter than the natural fire rotation in Arctic tundra regions. Here we report results of charcoal analysis on lake sediments from four Alaskan lakes to infer the broad spatial and temporal patterns of tundra-fire occurrence over the past 35 000 years. Background charcoal accumulation rates are low in all records (range is 0–0.05 pieces cm−2 yr−1), suggesting minimal biomass burning across our study areas. Charcoal peak analysis reveals that the mean fire-return interval (FRI; years between consecutive fire events) ranged from ca. 1650 to 6050 years at our sites, and that the most recent fire events occurred from ca. 880 to 7030 years ago, except for the CE 2007 Anaktuvuk River Fire. These mean FRI estimates are longer than the fire rotation periods estimated for the past 63 years in the areas surrounding three of the four study lakes. This result suggests that the frequency of tundra burning was higher over the recent past compared to the late Quaternary in some tundra regions. However, the ranges of FRI estimates from our paleofire records overlap with the expected values based on fire-rotation-period estimates from the observational fire data, and the differences are statistically insignificant. Together with previous tundra-fire reconstructions, these data suggest that the rate of tundra burning was spatially variable and that fires were extremely rare in our study areas throughout the late Quaternary. Given the rarity of tundra burning over multiple millennia in our study areas and the pronounced effects of fire on tundra ecosystem processes such as carbon cycling, dramatic tundra ecosystem changes are expected if anthropogenic climate change leads to more frequent tundra fires.
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Chipman, M. L., V. Hudspith, P. E. Higuera, P. A. Duffy, R. Kelly, W. W. Oswald, and F. S. Hu. "Spatiotemporal patterns of tundra fires: late-Quaternary charcoal records from Alaska." Biogeosciences Discussions 12, no. 3 (February 12, 2015): 3177–209. http://dx.doi.org/10.5194/bgd-12-3177-2015.
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Abstract. Anthropogenic climate change has altered many ecosystem processes in the Arctic tundra and may have resulted in unprecedented fire activity. Evaluating the significance of recent fires requires knowledge from the paleo-fire record because observational data in the Arctic span only several decades, much shorter than the natural fire rotation in Arctic tundra regions. Here we report results of charcoal analysis on lake sediments from four Alaskan lakes to infer the broad spatial and temporal patterns of tundra fire occurrence over the past 35 000 years. Background charcoal accumulation rates are low in all records (range = 0–0.05 pieces cm-2 year-1), suggesting minimal biomass burning across our study areas. Charcoal peak analysis reveals that the mean fire return interval (FRI; years between consecutive fire events) ranged from 1648 to 6045 years at our sites, and that the most recent fire events occurred from 882 to 7031 years ago, except for the CE 2007 Anaktuvuk River Fire. These mean FRI estimates are longer than the fire rotation periods estimated for the past 63 years in the areas surrounding three of the four study lakes. This result suggests that the frequency of tundra burning was higher over the recent past compared to the late Quaternary in some tundra regions. However, the ranges of FRI estimates from our paleo-fire records overlap with the expected values based on fire-rotation-period estimates from the observational fire data, and thus quantitative differences are not significant. Together with previous tundra-fire reconstructions, these data suggest that the rate of tundra burning was spatially variable and that fires were extremely rare in our study areas throughout the late Quaternary. Given the rarity of tundra burning over multiple millennia in our study areas and the pronounced effects of fire on tundra ecosystem processes such as carbon cycling, dramatic tundra ecosystem changes are expected if anthropogenic climate change leads to more frequent tundra fires.
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Oberbauer, S. F., S. C. Elmendorf, T. G. Troxler, R. D. Hollister, A. V. Rocha, M. S. Bret-Harte, M. A. Dawes, et al. "Phenological response of tundra plants to background climate variation tested using the International Tundra Experiment." Philosophical Transactions of the Royal Society B: Biological Sciences 368, no. 1624 (August 19, 2013): 20120481. http://dx.doi.org/10.1098/rstb.2012.0481.
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The rapidly warming temperatures in high-latitude and alpine regions have the potential to alter the phenology of Arctic and alpine plants, affecting processes ranging from food webs to ecosystem trace gas fluxes. The International Tundra Experiment (ITEX) was initiated in 1990 to evaluate the effects of expected rapid changes in temperature on tundra plant phenology, growth and community changes using experimental warming. Here, we used the ITEX control data to test the phenological responses to background temperature variation across sites spanning latitudinal and moisture gradients. The dataset overall did not show an advance in phenology; instead, temperature variability during the years sampled and an absence of warming at some sites resulted in mixed responses. Phenological transitions of high Arctic plants clearly occurred at lower heat sum thresholds than those of low Arctic and alpine plants. However, sensitivity to temperature change was similar among plants from the different climate zones. Plants of different communities and growth forms differed for some phenological responses. Heat sums associated with flowering and greening appear to have increased over time. These results point to a complex suite of changes in plant communities and ecosystem function in high latitudes and elevations as the climate warms.
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Niittynen, Pekka, Risto K. Heikkinen, and Miska Luoto. "Decreasing snow cover alters functional composition and diversity of Arctic tundra." Proceedings of the National Academy of Sciences 117, no. 35 (August 10, 2020): 21480–87. http://dx.doi.org/10.1073/pnas.2001254117.
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The Arctic is one of the least human-impacted parts of the world, but, in turn, tundra biome is facing the most rapid climate change on Earth. These perturbations may cause major reshuffling of Arctic species compositions and functional trait profiles and diversity, thereby affecting ecosystem processes of the whole tundra region. Earlier research has detected important drivers of the change in plant functional traits under warming climate, but studies on one key factor, snow cover, are almost totally lacking. Here we integrate plot-scale vegetation data with detailed climate and snow information using machine learning methods to model the responsiveness of tundra communities to different scenarios of warming and snow cover duration. Our results show that decreasing snow cover, together with warming temperatures, can substantially modify biotic communities and their trait compositions, with future plant communities projected to be occupied by taller plants with larger leaves and faster resource acquisition strategies. As another finding, we show that, while the local functional diversity may increase, simultaneous biotic homogenization across tundra communities is likely to occur. The manifestation of climate warming on tundra vegetation is highly dependent on the evolution of snow conditions. Given this, realistic assessments of future ecosystem functioning require acknowledging the role of snow in tundra vegetation models.
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Bradbury, Jane. "High Bacterial Biodiversity Found in Arctic Tundra." Frontiers in Ecology and the Environment 3, no. 10 (December 2005): 525. http://dx.doi.org/10.2307/3868606.
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Brooker, R. W., James F. Reynolds, and John D. Tenhunen. "Landscape Function and Disturbance in Arctic Tundra." Journal of Applied Ecology 34, no. 3 (June 1997): 832. http://dx.doi.org/10.2307/2404931.
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Virtanen, Risto, John-Arvid Grytnes, Jonathan Lenoir, Miska Luoto, Jari Oksanen, Lauri Oksanen, and Jens-Christian Svenning. "Productivity-diversity patterns in arctic tundra vegetation." Ecography 36, no. 3 (September 21, 2012): 331–41. http://dx.doi.org/10.1111/j.1600-0587.2012.07903.x.
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Loranty, Michael M., Scott J. Goetz, and Pieter S. A. Beck. "Tundra vegetation effects on pan-Arctic albedo." Environmental Research Letters 6, no. 2 (April 1, 2011): 024014. http://dx.doi.org/10.1088/1748-9326/6/2/024014.
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Loranty, Michael M., Scott J. Goetz, and Pieter S. A. Beck. "Tundra vegetation effects on pan-Arctic albedo." Environmental Research Letters 6, no. 2 (June 1, 2011): 029601. http://dx.doi.org/10.1088/1748-9326/6/2/029601.
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Kummerow, J., J. N. Mills, B. A. Ellis, S. J. Hastings, and A. Kummerow. "Downslope fertilizer movement in arctic tussock tundra." Ecography 10, no. 4 (November 1987): 312–19. http://dx.doi.org/10.1111/j.1600-0587.1987.tb00774.x.
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Benedict, James B. "Tundra Game Drives: an Arctic-Alpine Comparison." Arctic, Antarctic, and Alpine Research 37, no. 4 (November 2005): 425–34. http://dx.doi.org/10.1657/1523-0430(2005)037[0425:tgdaac]2.0.co;2.
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Lavrinenko, O. V., and I. A. Lavrinenko. "Vegetation of Loiseleurio procumbentis–Vaccinietea Eggler ex Schubert 1960 class in the East European tundras." Vegetation of Russia, no. 38 (July 2020): 27–84. http://dx.doi.org/10.31111/vegrus/2020.38.27.
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Communities of Loiseleurio procumbentis–Vaccinietea Eggler ex Schubert 1960 class and Deschampsio flexuosae–Vaccinietalia myrtilli Dahl 1957 order, widespread in the East European tundras, are represented by 2 alliances: Loiseleurio-Arctostaphylion Kalliola ex Nordhagen 1943 (dwarf-shrub-lichen communities in wind-blown habitats with well-drained automorphic soils) and Phyllodoco–Vaccinion myrtilli Nordhagen 1943 (moderately chionophytic dwarf-shrub communities in habitats with well-drained automorphic soils, moderately moist in summer) (definitions by: Ermakov, 2012). Acidic psammozems and podburs composed of sandy sediments are developed in such habitats. In the first half of the 20th century, such vegetation was described in the East European tundras in ecological-physiognomic classification traditions by Soviet geobotanists V. N. Andreyev, I. D. Bogdanovskaya-Giyenef, A. A. Dedov and Z. N. Smirnova. They attributed it to lichen, dwarf-shrub-lichen and dwarf-shrub vegetation types on sandy substrates. Based upon the analysis of 196 relevés (142 of them are in this paper) from 34 sites on the Kolguyev Isl., Malozemelskaya and Bolshezemelskaya tundras, Pechora River Delta and Northern Timan Ridge (Fig. 1), we described 5 associations (including 3 subassociations and 10 variants) by Braun-Blanquet classification approach; 4 syntaxa are left in the rank of community type. Two associations of Loiseleurio-Arctostaphylion alliance, first described in the mountain regions of Fennoscandia, are also basic in the East European tundras. The area of ass. Empetro–Betuletum nanae Nordhagen 1943 occupying the lower sub-belt of the mountain-tundra belt of Fennoscandia, is also common in the plain areas in more moderate conditions in the south tundra and forest-tundra (Table 4, rel. 1–13; Table 6, syntaxon 10; Fig. 9а, б, 10). Ass. Loiseleurio-Diapensietum (Fries 1913) Nordhagen 1943, described in the upper sub-belt of the mountain-tundra belt, is represented by subass. salicetosum nummulariae Koroleva 2006 in the plain areas with its distribution area from typical tundra on Kolguyev Isl. to the northern forest-tundra in the mainland. Three variants of subassociation are identified on the latitudinal gradient: inops — on the Kolguyev Isl., Diapensia lapponica — in the continental typical tundra and Loiseleuria procumbens — in the south tundra and forest-tundra (Table 2, rel. 1–35; Table 6, syntaxa 6–9; Fig. 4а–в, 5, 6). Subass. Loiseleurio-Diapensietumsalicetosum nummulariae was first described in the tundra zone of the Kola Peninsula for petrophytic communities with a polygonal structure in oligochion and achion habitats (Koroleva, 2006). We attributed dwarf-shrub-lichen communities dominated by chionophobic lichens (Flavocetraria nivalis, Alectoria nigricans, A. ochroleuca, Bryocaulon divergens) with irregularly-mosaic horizontal structure on sandy substrates to this subassociation due to the high similarity of the species composition (Table 2). Ass. Empetro hermaphroditi–Salicetum nummulariae Bogdanovskaya-Giyenef ex Lavrinenko et Lavrinenko ass. nov. hoc loco (Table 1, rel. 1–18; nomenclatural type (neotypus hoc loco) — rel. 6 (author’ number — К157, Kolguyev Isl., Khayropskoye Lake environs, 10.09.2007, authors — O. V. Lavrinenko, I. A. Lavrinenko); Table 6, syntaxa 1–4; Fig. 2а–в, 3) with variants Tanacetum bipinnatum, Racomitrium canescens and Betula nana unites dwarf-shrub communities corresponding to different stages of the succession of the overgrown of open sands. They are common in the typical tundra subzone on Kolguyev Isl. and in the north-east part of Malozemelskaya tundra in sites with large sandy outcrops. The area of ass. Cladonietum rangiferino–arbusculae ass. nov. hoc loco (Table 4, rel. 14–20; nomenclatural type (holotypus hoc loco) — rel. 19 (author’ number — Т29,, Malozemelskaya Tundra, Kolokolkova Bay, Tobseda village (uninhabited) vicinity, 14.07.2002, author — O. V. Lavrinenko); Table 6, syntaxon 11; Fig. 12а, б) is so far limited by the coastal part of the Malozemelskaya tundra (it will probably be expanded). Communities transformed by reindeer grazing are left in the rank of community type — Dicranum elongatum–Salix nummularia com. type (Table 3, rel. 1–28; Table 6, syntaxon 5; Fig. 7а, б, 8) as well as draft-shrub-lichen with Cladonia stellaris — Cladonia stellaris com. type (Table 4, rel. 21–22; Fig. 11а). Regional characteristic species are established for Loiseleurio-Arctostaphylion alliance — psammophytic moss Polytrichum piliferum and lichens Cetraria aculeata (incl. C. muricata), C. nigricans, Cladonia pyxidata, C. cervicornis subsp. verticillata. The basic association— Phyllodoco–Vaccinietum myrtilli Nordhagen 1943 in Phyllodoco–Vaccinion myrtilli alliance in the East European tundras is represented by two subassociations: P.–V. m. salicetosum herbaceae subass. nov. hoc loco(Table 5, rel. 1–14; nomenclatural type (holotypus hoc loco) — rel. 4 (author’ number — 88_12, Kolguyev Isl., Bugryanka River in the midstream, 21.08.2012, authors — O. V. Lavrinenko, I. A. Lavrinenko); Table 6, syntaxon 12; Fig. 13а and б, 14, 15) — on Kolguyev Isl. and P.–V. m. veratretosum lobeliani subass. nov. hoc. loco (Table 5, rel. 15–33; nomenclatural type (holotypus hoc loco) — rel. 24 (author’ number — БН31_14, Bolshezemelskaya Tundra, Bolvanskiy Nos Cape, 27.07.2014, authors — O. V. Lavrinenko, I. A. Lavrinenko); Table 6, syntaxon 13; Fig. 16а–в, 17 ) — in the mainland areas in typical, south tundra subzones and northern forest-tundra. Floristic differences between them are caused by differences both in area distribution of some species, and habitats. There are some taxa of Salicetea herbaceae Br.-Bl. 1948 class on Kolguyev Isl, which indicates more nival conditions. The subass. P.–V. m. salicetosum herbaceae seems to be widespread on the Kola Peninsula. There are 2 variants in each subassociation: Vaccinium myrtillus and Chamaepericlymenum suecicum. Vaccinium myrtillus communities with Cladonia stellaris and Vacciniumuliginosum subsp. microphyllum are left in the rank of community type — Cladonia stellaris–Vaccinium myrtillus com. type (Table 5, rel. 34, 35; Fig. 18) and Vaccinium microphyllumcom. type (Table 5, rel. 36–39; Table 6, syntaxon 15; Fig. 19) due to the small number of relevés. The results of geographical analysis of vascular plant coenoflora of Loiseleurio-Arctostaphylion alliance syntaxa are as follows: dominating arctic species — 45 %, hypoarctic — 32 % and boreal — 23 %; there are no boreal species among the high-constant ones, the number arctic and hypoarctic species is approximately equal. The analogous data for of Phyllodoco–Vaccinion myrtilli alliance syntaxa: arctic, hypoarctic and boreal fractions — 33 % each; hypoarctic species dominates among the high-constant ones, boreal (including arcto-boreal) — 2times less and only 2 — arctic-alpine species.
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Lavrinenko, O. V., N. V. Matveyeva, and I. A. Lavrinenko. "Сommunities of the class Scheuchzerio–Caricetea nigrae (Nordh. 1936) Tx. 1937 in the East European tundras." Vegetation of Russia, no. 28 (2016): 55–88. http://dx.doi.org/10.31111/vegrus/2016.28.55.
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There are few publications on the classification of vegetation of Scheuchzerio–Caricetea nigrae class in the Arctic (Daniёls, 1982; Matveyeva, 1994; Zanokha, 2003). In Russia classification of mires is more or less well designed for the taiga zone of the European North and the West Siberia. Communities of sedge-hypnum mires and sedge-sphagnum hollows of flat palsa-bogs in the East European tundra are described in the dominant classification traditions (Andreev, 1932; Bogdanovskaya-Gienef, 1938; Dedov, 2006). N. Yа. Katz (1936) briefly described the vegetation of the Arctic mineral sedge mires on the Vaygach Island. In present paper the results of the mires classification carried out upon the basis of 148 relevés made in 1998–2014 in 26 sites in the East European tundra along the latitudinal gradient from typical tundra to northern forest-tundra.
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Bradley, Raymond S., and Mark C. Serreze. "Topoclimatic Studies of a High Arctic Plateau Ice Cap." Journal of Glaciology 33, no. 114 (1987): 149–58. http://dx.doi.org/10.1017/s0022143000008625.
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AbstractMeteorological observations on and around a small, exposed plateau ice cap on north-eastern Ellesmere Island, N.W.T., Canada, were carried out in the northern summers of 1982 and 1983. The objective was to assess the effect of the ice cap on local climate as the melt season progressed. In 1982, seasonal net radiation totals were lowest on the ice cap and greatest at the site farthest from the ice cap. The ice-cap site received only 35% of net radiation totals on the surrounding tundra. This reflects a gradient in albedo; albedo changed most markedly away from the ice cap as the summer progressed. A thermal gradient was observed along a transect perpendicular to the ice-cap edge; this gradient was greatest at low levels (15 cm) and was maximized under cloud-free conditions. The “cooling effect” of the ice cap was less at the start of the ablation season than later. Low-level inversions occurred more frequently over the ice cap than over the snow-free tundra. Overall, melting degree days on the ice cap were only 40–65% of those on the adjacent tundra. A model of interactions between the atmosphere and a snow and ice cover, or a snow-free tundra/felsenmeer surface is proposed. Observations indicate that the ice cap has a cooling effect on the lower atmosphere relative to the adjacent snow-free tundra; this effect is absent when snow cover is extensive (as in 1983).
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Bradley, Raymond S., and Mark C. Serreze. "Topoclimatic Studies of a High Arctic Plateau Ice Cap." Journal of Glaciology 33, no. 114 (1987): 149–58. http://dx.doi.org/10.3189/s0022143000008625.
Full textAbstract:
AbstractMeteorological observations on and around a small, exposed plateau ice cap on north-eastern Ellesmere Island, N.W.T., Canada, were carried out in the northern summers of 1982 and 1983. The objective was to assess the effect of the ice cap on local climate as the melt season progressed. In 1982, seasonal net radiation totals were lowest on the ice cap and greatest at the site farthest from the ice cap. The ice-cap site received only 35% of net radiation totals on the surrounding tundra. This reflects a gradient in albedo; albedo changed most markedly away from the ice cap as the summer progressed. A thermal gradient was observed along a transect perpendicular to the ice-cap edge; this gradient was greatest at low levels (15 cm) and was maximized under cloud-free conditions. The “cooling effect” of the ice cap was less at the start of the ablation season than later. Low-level inversions occurred more frequently over the ice cap than over the snow-free tundra. Overall, melting degree days on the ice cap were only 40–65% of those on the adjacent tundra. A model of interactions between the atmosphere and a snow and ice cover, or a snow-free tundra/felsenmeer surface is proposed. Observations indicate that the ice cap has a cooling effect on the lower atmosphere relative to the adjacent snow-free tundra; this effect is absent when snow cover is extensive (as in 1983).
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Stieglitz, Marc, John Hobbie, Anne Giblin, and George Kling. "Hydrologic modeling of an arctic tundra watershed: Toward Pan-Arctic predictions." Journal of Geophysical Research: Atmospheres 104, no. D22 (November 1, 1999): 27507–18. http://dx.doi.org/10.1029/1999jd900845.
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Lozhkin, A. V., and P. M. Anderson. "Vegetation responses to interglacial warming in the Arctic: examples from Lake El'gygytgyn, Far East Russian Arctic." Climate of the Past 9, no. 3 (June 11, 2013): 1211–19. http://dx.doi.org/10.5194/cp-9-1211-2013.
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Abstract. Preliminary analyses of Lake El'gygytgyn sediment indicate a wide range of ecosystem responses to warmer than present climates. While palynological work describing all interglacial vegetation is ongoing, sufficient data exist to compare recent warm events (the postglacial thermal maximum, PGTM, and marine isotope stage, MIS5) with "super" interglaciations (MIS11, MIS31). Palynological assemblages associated with these climatic optima suggest two types of vegetation responses: one dominated by deciduous taxa (PGTM, MIS5) and the second by evergreen conifers (MIS11, MIS31). MIS11 forests show a similarity to modern Picea–Larix–Betula–Alnus forests of Siberia. While dark coniferous forest also characterizes MIS31, the pollen taxa show an affinity to the boreal forest of the lower Amur valley (southern Russian Far East). Despite vegetation differences during these thermal maxima, all glacial–interglacial transitions are alike, being dominated by deciduous woody taxa. Initially Betula shrub tundra established and was replaced by tundra with tree-sized shrubs (PGTM), Betula woodland (MIS5), or Betula–Larix (MIS11, MIS31) forest. The consistent occurrence of deciduous forest and/or high shrub tundra before the incidence of maximum warmth underscores the importance of this biome for modeling efforts. The El'gygytgyn data also suggest a possible elimination or massive reduction of Arctic plant communities under extreme warm-earth scenarios.
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Sikes, Derek S., Michael L. Draney, and Brandi Fleshman. "Unexpectedly high among-habitat spider (Araneae) faunal diversity from the Arctic Long-Term Experimental Research (LTER) field station at Toolik Lake, Alaska, United States of America." Canadian Entomologist 145, no. 2 (March 22, 2013): 219–26. http://dx.doi.org/10.4039/tce.2013.5.
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AbstractA comparison is made between a three-year structured-sampling study that compared spider faunas of two tundra habitats and a single-year unstructured-sampling study, both within the Arctic Long-Term Experimental Research (LTER) field station at Toolik Lake, Alaska, United States of America. The three-year study documented 51 species and predicted a total of 60 species for the area. Our one season study documented 39 species, of which 24, or 62%, are not shared by the three-year study, raising the total count for the LTER to 75 species. These findings emphasise limitations of species richness estimation methods and help dispel the perception that Arctic tundras are homogeneous and species poor.
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Titkova, T. B., A. N. Zolotokrylin, and V. V. Vinogradov. "SPECTRAL CHARACTERISTICS OF TUNDRA AND FOREST TUNDRA LANDSCAPES DURING THE YEARS OF SUMMER TEMPERATURE ANOMALIES." Fundamental and Applied Climatology 4 (2020): 88–103. http://dx.doi.org/10.21513/2410-8758-2020-4-88-103.
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The warming at high latitudes, remaining in recent years, has a direct impact on arctic and subarctic landscapes. Possible changes of this landscapes under the climate warming are closely related with regulatory mechanisms for the underlying surface temperature. The circumstances of forming radiation and evapotranspirational regulatory mechanisms for the surface temperature were explored for tundra (from arctic to southern) and forest tundra landscapes of Novaya Zemlya and Western Siberia. The MODIS data of surface spectral characteristics were used, and more specifically albedo (Al) and surface temperature (Ts) for July 2000-2019. The work shows that the radiation regulatory mechanism of the surface temperature is dominated in glacial and polar desert landscapes of Arctic and Subarctic with a predominance of stony and rubble types of surfaces with lichens. At the same time, radiative surface temperature control mechanism in mountain and arctic tundra of Novaya Zemlya almost does not depend on weather anomalies and so far has a little implication for the temperature trend. In the mainland and forest tundra, the evapotranspirational regulatory mechanism for the surface temperature starts to prevail. This is supported by the increasing of monthly average air temperatures to 15-16°С, which is beneficial to the vegetation diversity. In subzones of the southern and forest tundra, the connection of albedo and surface temperature depends on altitudes, slope exposure and especially on extreme temperature anomalies. In basins, or hydromorphic complexes, in cold years against the backdrop of wetlands the regulatory mechanism for the surface temperature prevails, and in warm years the humidity decreasing leads to the highest vegetation development and the connection type can turn into the evapotranspirational one. On the high grounds the return process is observed, which is also connected with the changes in humidification conditions. In forest tundra, where the air temperature rises and the canopy height increases, the evapotranspirational mechanism of spectral parameters Al–Ts connections is weakening. As a result, in southern and forest tundra two balanced steady states of the connection types of surface spectral characteristics can exist in relation to lighting conditions and temperature anomalies.
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Chytrý, Milan, Fred J. A. Danlëls, Romeo Di Pietro, Natalia Koroleva, and Ladislav Mucina. "Nomenclature Adjustments and New Syntaxa of the Arctic, Alpine and Oro-Mediterranean Vegetation." Hacquetia 14, no. 2 (December 1, 2015): 277–88. http://dx.doi.org/10.1515/hacq-2015-0004.
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Abstract During preparation of the European checklist of vegetation units (EuroVegChecklist), it became clear that some earlier described syntaxa need to be typified in order to stabilize nomenclature and some new syntaxa need to be described. Here we propose nomenclature adjustments and formal description of four new alliances for the Arctic, alpine and oro-Mediterranean vegetation of Europe, Greenland and Anatolia. First, we typify the class Juncetea trifidi. Second, we describe four new alliances, such as the Puccinellion nuttallianae (Low-Arctic salt steppes of Greenland; class Saxifrago tricuspidatae-Calamagrostietea purpurascentis), Dryado octopetalae- Caricion arctisibiricae (Arctic tundra vegetation of north-eastern European Russia; class Carici rupestris- Kobresietea bellardii), Leontopodio nivalis-Elynion myosuroidis (southern European alpine tundra vegetation; class Carici rupestris-Kobresietea bellardii) and Lagotido uralensis-Caricion ensifoliae (alpine tundra vegetation of the Southern Ural Mountains; class Juncetea trifidi). Two new associations are described within the first two of these alliances. Finally, we present an interpretation of the alliance Muscario-Scillion nivalis.
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Ala-aho, Pertti, Jeffrey M. Welker, Hannah Bailey, Stine Højlund Pedersen, Ben Kopec, Eric Klein, Moein Mellat, Kaisa-Riikka Mustonen, Kashif Noor, and Hannu Marttila. "Arctic Snow Isotope Hydrology: A Comparative Snow-Water Vapor Study." Atmosphere 12, no. 2 (January 25, 2021): 150. http://dx.doi.org/10.3390/atmos12020150.
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The Arctic’s winter water cycle is rapidly changing, with implications for snow moisture sources and transport processes. Stable isotope values (δ18O, δ2H, d-excess) of the Arctic snowpack have potential to provide proxy records of these processes, yet it is unclear how well the isotope values of individual snowfall events are preserved within snow profiles. Here, we present water isotope data from multiple taiga and tundra snow profiles sampled in Arctic Alaska and Finland, respectively, during winter 2018–2019. We compare the snowpack isotope stratigraphy with meteoric water isotopes (vapor and precipitation) during snowfall days, and combine our measurements with satellite observations and reanalysis data. Our analyses indicate that synoptic-scale atmospheric circulation and regional sea ice coverage are key drivers of the source, amount, and isotopic composition of Arctic snowpacks. We find that the western Arctic tundra snowpack profiles in Alaska preserved the isotope values for the most recent storm; however, post depositional processes modified the remaining isotope profiles. The overall seasonal evolution in the vapor isotope values were better preserved in taiga snow isotope profiles in the eastern Arctic, where there is significantly less wind-driven redistribution than in the open Alaskan tundra. We demonstrate the potential of the seasonal snowpack to provide a useful proxy for Arctic winter-time moisture sources and propose future analyses.
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Beamish, Alison L., Wiebe Nijland, Marc Edwards, Nicholas C. Coops, and Greg H. R. Henry. "Phenology and vegetation change measurements from true colour digital photography in high Arctic tundra." Arctic Science 2, no. 2 (June 2016): 33–49. http://dx.doi.org/10.1139/as-2014-0003.
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Manual collection of accurate phenology data is time-consuming and expensive. In this study, we investigate whether repeat colour digital photography can be used (1) to identify phenological patterns, (2) to identify differences in vegetation due to experimental warming and site moisture conditions, and (3) as a proxy for biomass. Pixel values (RGB) were extracted from images taken of permanent plots in long-term warming experiments in three tundra communities at a high Arctic site during one growing season. The Greenness Excess Index (GEI) was calculated from image data at the plot scale (1 × 1 m) as well as for two species, Dryas integrifolia and Salix arctica. GEI values were then compared to corresponding field-based phenology observations. GEI and Normalized Difference Vegetation Index (NDVI) values from a paired set of true colour and infrared images were compared with biomass data. The GEI values followed seasonal phenology at the plot and species scale and correlated well with standardized observations. GEI correlated well with biomass and was able to detect quantitative differences between warmed and control plots and the differences between communities due to site-specific moisture conditions. We conclude that true colour images can be used effectively to monitor phenology and biomass in high Arctic tundra. The simplicity and affordability of the photographic method represents an opportunity to expand observations in tundra ecosystems.
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Cristóbal, Jordi, Anupma Prakash, Martha C. Anderson, William P. Kustas, Eugénie S. Euskirchen, and Douglas L. Kane. "Estimation of surface energy fluxes in the Arctic tundra using the remote sensing thermal-based Two-Source Energy Balance model." Hydrology and Earth System Sciences 21, no. 3 (March 7, 2017): 1339–58. http://dx.doi.org/10.5194/hess-21-1339-2017.
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Abstract. The Arctic has become generally a warmer place over the past decades leading to earlier snow melt, permafrost degradation and changing plant communities. Increases in precipitation and local evaporation in the Arctic, known as the acceleration components of the hydrologic cycle, coupled with land cover changes, have resulted in significant changes in the regional surface energy budget. Quantifying spatiotemporal trends in surface energy flux partitioning is key to forecasting ecological responses to changing climate conditions in the Arctic. An extensive local evaluation of the Two-Source Energy Balance model (TSEB) – a remote-sensing-based model using thermal infrared retrievals of land surface temperature – was performed using tower measurements collected over different tundra types in Alaska in all sky conditions over the full growing season from 2008 to 2012. Based on comparisons with flux tower observations, refinements in the original TSEB net radiation, soil heat flux and canopy transpiration parameterizations were identified for Arctic tundra. In particular, a revised method for estimating soil heat flux based on relationships with soil temperature was developed, resulting in significantly improved performance. These refinements result in mean turbulent flux errors generally less than 50 W m−2 at half-hourly time steps, similar to errors typically reported in surface energy balance modeling studies conducted in more temperate climatic regimes. The MODIS leaf area index (LAI) remote sensing product proved to be useful for estimating energy fluxes in Arctic tundra in the absence of field data on the local biomass amount. Model refinements found in this work at the local scale build toward a regional implementation of the TSEB model over Arctic tundra ecosystems, using thermal satellite remote sensing to assess response of surface fluxes to changing vegetation and climate conditions.
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Melekhina, Elena N. "Analysis of Oribatid Fauna of the East European Tundra with First Reported Data of Subpolar Urals." Diversity 12, no. 6 (June 10, 2020): 235. http://dx.doi.org/10.3390/d12060235.
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This study presents data on the oribatid mite fauna of the Subpolar Urals for the first time. Observations were made in the Lembekoyu River valley and 35 species of oribatid mites from 24 genera and 21 families were found. The analysis of taxonomic diversity and distribution of East European tundra oribatid mite species is presented based on available literature and the author’s own research findings. The taxonomic list includes 163 species from 81 genera and 45 families. Ceratozetidae (15 species), Crotoniidae (14 species), Oppiidae (12 species), Suctobelbidae (12 species), Damaeidae (9 species), Brachychthoniidae (8 species), Phthiracaridae (5 species), Humerobatidae (5 species), Achipteriidae (5 species), Punctoribatidae (5 species), and Galumnidae (5 species) are the leading families, comprising more than 58% of all species. The zoogeographical structure of the fauna is dominated by widely distributed Holarctic, cosmopolitan, and semi-cosmopolitan species. The share of Palaearctic species is 23%. The specificity of the fauna of East European tundra manifests itself in the small group of Arctic species, both in the mainland tundra and on the Arctic islands. A complex of arctic-boreal species, widely distributed in the Eurasian sector of the Arctic, is distinguished.
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Zona, Donatella, Beniamino Gioli, Róisín Commane, Jakob Lindaas, Steven C. Wofsy, Charles E. Miller, Steven J. Dinardo, et al. "Cold season emissions dominate the Arctic tundra methane budget." Proceedings of the National Academy of Sciences 113, no. 1 (December 22, 2015): 40–45. http://dx.doi.org/10.1073/pnas.1516017113.
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Arctic terrestrial ecosystems are major global sources of methane (CH4); hence, it is important to understand the seasonal and climatic controls on CH4 emissions from these systems. Here, we report year-round CH4 emissions from Alaskan Arctic tundra eddy flux sites and regional fluxes derived from aircraft data. We find that emissions during the cold season (September to May) account for ≥50% of the annual CH4 flux, with the highest emissions from noninundated upland tundra. A major fraction of cold season emissions occur during the “zero curtain” period, when subsurface soil temperatures are poised near 0 °C. The zero curtain may persist longer than the growing season, and CH4 emissions are enhanced when the duration is extended by a deep thawed layer as can occur with thick snow cover. Regional scale fluxes of CH4 derived from aircraft data demonstrate the large spatial extent of late season CH4 emissions. Scaled to the circumpolar Arctic, cold season fluxes from tundra total 12 ± 5 (95% confidence interval) Tg CH4 y−1, ∼25% of global emissions from extratropical wetlands, or ∼6% of total global wetland methane emissions. The dominance of late-season emissions, sensitivity to soil environmental conditions, and importance of dry tundra are not currently simulated in most global climate models. Because Arctic warming disproportionally impacts the cold season, our results suggest that higher cold-season CH4 emissions will result from observed and predicted increases in snow thickness, active layer depth, and soil temperature, representing important positive feedbacks on climate warming.
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Hofgaard, Annika, and Karen A. Harper. "Tree recruitment, growth, and distribution at the circumpolar forest–tundra transition: introduction." Canadian Journal of Forest Research 41, no. 3 (March 2011): 435–36. http://dx.doi.org/10.1139/x10-238.
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Causes and consequences of changes in the circumpolar forest–tundra transition have received recent interest due to the increasing awareness of human-caused global climate change. The International Polar Year core project PPS Arctic focused these topics through exploring processes, changes, and spatiotemporal variability of biotic and abiotic drivers of change in the forest–tundra transition. The papers in this special feature present constraints and drivers of tree recruitment and tree encroachment of tundra areas, climate – tree growth relations in the ecotone, and changes in tree spatial pattern across the forest–tundra ecotone.