Environment, vegetation and greenness (NDVI) along the North America and Eurasia Arctic transects

Walker, Donald A.; Epstein, Howard E.; Raynolds, Martha K.; Kuss, Patrick; Kopecký, Martin; Frost, G. V.; Daniëls, Fred J.A.; Leibman, Marina; Москаленко, Н. Г.; Матышак, Г. В.; Khitun, Olga V.; Khomutov, Artem; Forbes, Bruce C.; Bhatt, Uma S.; Kade, Anja; Vonlanthen, Corinne M.; Tichý, Lubomír

doi:10.1088/1748-9326/7/1/015504

Cited by 129 publications

(110 citation statements)

References 52 publications

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“…Over the last 5 years, new clavarioid species typical predominantly of the ″forest″ ecosystems have been discovered more and more often in the high-latitude regions of the European part of the Arctic (Shiryaev 2015b); this can be explained by warming of the climate and by expansion of the forest vegetation into previously forestless ″tundra″ regions (Walker et al 2012). On the other hand, no new species have been registered in continental regions of Yakutia during the same period.…”

Section: Resultsmentioning

confidence: 99%

“…Thanks to current climatic changes, these species appear in water sheds and oust aggressively conventional cryophilic elements of the tundra biota. At the same time, increasing diversity of the flora in the European tundra as a whole and those specific local floras are more obvious here compared to continental regions of Siberia (Yurtsev et al 2004; Walker et al 2012; Belonovskaya et al 2016). Traditionally, these processes are studied on the basis of various groups of animals and plants, whereas representatives of the Fungi Kingdom are extremely uncommon to be used as model groups (Dahlberg et al 2013; Geml et al 2016).…”

Section: Introductionmentioning

confidence: 83%

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Longitudinal changes of clavarioid funga (Basidiomycota) diversity in the tundra zone of Eurasia

Shiryaev

2017

Mycology

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The study deals with certain variations of the diversity level of clavarioid funga in the 33 localities (100 km2 each) inside seven longitudinal sectors (100,000 km2) situated along the gradient of the climatic continentality of the Eurasian tundra zone. As continentality increases, from the maritime climate of Fennoscandia to the continental climate of Yakutia, α-diversity and γ-diversity decrease considerably. On the other side, spatial turnover of species, or β-diversity, grows in the direction of continental areas. This paper uses the following methods to assess the spatial turnover: Whittaker’s index and mean Jaccard similarity index, as well as by several other parameters. In addition, our data show that the genus Typhula is richest in the tundra, and its share in the structure of the clavarioid funga grows as the studied area decreases, as well as when the environmental conditions become more severe (continentality of the climate). Also, the paper discusses the issue of newly emerging taiga fungi species in the European Arctic, which is connected with climatic warming followed by ″greening″ of the tundra. Note that in the cryo-semiarid continental climate of Yakutia, where climatic changes are just as pronounced, no new taxons have been discovered so far.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 83%

Longitudinal changes of clavarioid funga (Basidiomycota) diversity in the tundra zone of Eurasia

Shiryaev

2017

Mycology

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“…Such "toposequences" are part of the underlying conceptual framework for describing Arctic vegetation at the landscape scale for the circumpolar Arctic [35]. The vegetation, soils, patterned ground features and biomass of the small east-facing hill slope were previously characterized and mapped during several studies at this location [39,[52][53][54][55]. The grids are positioned on the hill crest, at 325 m, the midslope, at 310 m (representing also the zonal Happy Valley site), and the footslope, at 300 m. The main difference between the hillcrest and the zonal midslope community is that the hill crest is somewhat drier with more nonsorted circles that have the plant community Cladino-Vaccinietum vitis-idaeae [39], which has similar species composition to Sphagno-Eriophoretum vaginati, but with no Sphagnum and higher cover of grass, nontussock sedges, prostrate evergreen dwarf shrubs, the moss Racomitrium lanuginosum, and lichens.…”

Section: Environmental Gradients/zones and Vegetation Descriptionmentioning

confidence: 99%

Ground-Based Hyperspectral Characterization of Alaska Tundra Vegetation along Environmental Gradients

et al. 2013

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Abstract:Remote sensing has become a valuable tool in monitoring arctic environments. The aim of this paper is ground-based hyperspectral characterization of Low Arctic Alaskan tundra communities along four environmental gradients (regional climate, soil pH, toposequence, and soil moisture) that all vary in ground cover, biomass, and dominating plant communities. Field spectroscopy in connection with vegetation analysis was carried out in summer 2012, along the North American Arctic Transect (NAAT). Spectral metrics were extracted, including the averaged reflectance and absorption-related metrics such as absorption depths and area of continuum removal. The spectral metrics were investigated with respect to "greenness", biomass, vegetation height, and soil moisture regimes. The results show that the surface reflectances of all sites are similar in shape with a reduced near-infrared (NIR) reflectance that is specific for low-growing biomes. The main spectro-radiometric findings are: (i) Southern sites along the climate gradient have taller shrubs and greater overall vegetation biomass, which leads to higher reflectance in the NIR. (ii) Vegetation height and surface wetness are two antagonists that balance each other out with respect to the NIR reflectance along the toposequence and soil moisture gradients. (iii) Moist acidic OPEN ACCESSRemote Sens. 2013, 5 3972 tundra (MAT) sites have "greener" species, more leaf biomass, and green-colored moss species that lead to higher pigment absorption compared to moist non-acidic tundra (MNT) sites. (iv) MAT and MNT plant community separation via narrowband Normalized Difference Vegetation Index (NDVI) shows the potential of hyperspectral remote sensing applications in the tundra.

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“…Arctic plant habitats are characterized by high spatial heterogeneity, often at relatively small scales (submeter), in response to moisture gradients, limiting the ability to predict phenological changes detected by remote sensing at the landscape scales [25][26][27]. Although the vegetation in some regions of the Arctic is well studied, with many studies documenting shifts in habitat type, NDVI, productivity, and phenology in recent decades [17,21,23,[28][29][30][31], most of these data were collected once, twice, or very rarely three times per week. As a result, few studies to date have investigated the role of daily air temperatures on the short-term progression of greening and senescence in tundra habitats.…”

Section: Introductionmentioning

confidence: 99%

Short-Term Impacts of the Air Temperature on Greening and Senescence in Alaskan Arctic Plant Tundra Habitats

et al. 2017

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Climate change is warming the temperatures and lengthening the Arctic growing season with potentially important effects on plant phenology. The ability of plant species to acclimate to changing climatic conditions will dictate the level to which their spatial coverage and habitat-type dominance is different in the future. While the effect of changes in temperature on phenology and species composition have been observed at the plot and at the regional scale, a systematic assessment at medium spatial scales using new noninvasive sensor techniques has not been performed yet. At four sites across the North Slope of Alaska, changes in the Normalized Difference Vegetation Index (NDVI) signal were observed by Mobile Instrumented Sensor Platforms (MISP) that are suspended over 50 m transects spanning local moisture gradients. The rates of greening (measured in June) and senescence (measured in August) in response to the air temperature was estimated by changes in NDVI measured as the difference between the NDVI on a specific date and three days later. In June, graminoid-and shrub-dominated habitats showed the greatest rates of NDVI increase in response to the high air temperatures, while forb-and lichen-dominated habitats were less responsive. In August, the NDVI was more responsive to variations in the daily average temperature than spring greening at all sites. For graminoid-and shrub-dominated habitats, we observed a delayed decrease of the NDVI, reflecting a prolonged growing season, in response to high August temperatures. Consequently, the annual C assimilation capacity of these habitats is increased, which in turn may be partially responsible for shrub expansion and further increases in net summer CO 2 fixation. Strong interannual differences highlight that long-term and noninvasive measurements of such complex feedback mechanisms in arctic ecosystems are critical to fully articulate the net effects of climate variability and climate change on plant community and ecosystem processes.

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Environment, vegetation and greenness (NDVI) along the North America and Eurasia Arctic transects

Cited by 129 publications

References 52 publications

Longitudinal changes of clavarioid funga (Basidiomycota) diversity in the tundra zone of Eurasia

Longitudinal changes of clavarioid funga (Basidiomycota) diversity in the tundra zone of Eurasia

Ground-Based Hyperspectral Characterization of Alaska Tundra Vegetation along Environmental Gradients

Short-Term Impacts of the Air Temperature on Greening and Senescence in Alaskan Arctic Plant Tundra Habitats

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