Spatial and Temporal Heterogeneity of Vegetation Properties among Four Tundra Plant Communities at Ivotuk, Alaska, U.S.A

Riedel, Sebastian; Epstein, Howard E.; Walker, Donald A.; Richardson, D. L.; Calef, M. P.; Edwards, Erika J.; Moody, Amber S.

doi:10.1657/1523-0430(2005)037[0025:sathov]2.0.co;2

Cited by 44 publications

(54 citation statements)

References 32 publications

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“…NDVI is therefore frequently used to evaluate vegetation changes in high latitude environments [1,[6][7][8][9][10][11][12][13][14][15][16]. One of the previous analyses at the site of interest for this study (Ivotuk, Alaska) showed that, at the landscape scale, broad-band NDVI obtained by averaging hyperspectral bands across red and near infrared (NIR) regions had the greatest peak growing season values for shrub tundra (ST), compared to three other tundra plant communities [17]. While NDVI may be useful for separating some communities at peak growing season, it may be problematic during the early or late growing season when vegetation communities are more similar (Figure 1).…”

Section: Introductionmentioning

confidence: 95%

“…The primary study site of Ivotuk, Alaska (68.49˝N, 155.74˝W) is located on the North Slope of the Brooks Mountain Range [8,17,54] and was one of seven sites established as part of the Arctic Transitions in the Land-Atmosphere System (ATLAS) project [16,55,56]. Ivotuk is part of the Western Alaska Transect that starts in the north at Barrow and goes south through Atqasuk and Oumalik to Ivotuk [16,42,55,57].…”

Section: Study Sitesmentioning

confidence: 99%

“…The site received an average annual rainfall of 202 mm, had a July maximum temperature of approximately 12˝C and an annual temperature of´10.9˝C with a 110-day growing season from 1991-2001, a time period including the sampling period for the Ivotuk vegetation data [8,17,42]. Aerial vegetation coverage is nearly 100% for Ivotuk, and all four plant communities in this study-MAT, MNT, MT, and ST-occur within a 2 km 2 area [17]. ST had the greatest total aboveground peak growing season biomass (1291 g/m 2 ).…”

Section: Study Sitesmentioning

confidence: 99%

“…We first develop a model for identifying different vegetation communities at Ivotuk, Alaska using hyperspectral data; this discrimination model is then applied to five other sites on the North Slope of Alaska to test its utility in identifying tundra vegetation across geographical space. [17]. Measurements were taken using an Analytical Spectral Devices FieldSpec spectro-radiometer.…”

Section: Introductionmentioning

confidence: 99%

“…Measurements were taken using an Analytical Spectral Devices FieldSpec spectro-radiometer. [17]. Measurements were taken using an Analytical Spectral Devices FieldSpec spectro-radiometer.…”

Section: Introductionmentioning

confidence: 99%

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Differentiating among Four Arctic Tundra Plant Communities at Ivotuk, Alaska Using Field Spectroscopy

et al. 2016

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Warming in the Arctic has resulted in changes in the distribution and composition of vegetation communities. Many of these changes are occurring at fine spatial scales and at the level of individual species. Broad-band, coarse-scale remote sensing methods are commonly used to assess vegetation changes in the Arctic, and may not be appropriate for detecting these fine-scale changes; however, the use of hyperspectral, high resolution data for assessing vegetation dynamics remains scarce. The aim of this paper is to assess the ability of field spectroscopy to differentiate among four vegetation communities in the Low Arctic of Alaska. Primary data were collected from the North Slope site of Ivotuk, Alaska (68.49˝N, 155.74˝W) and analyzed using spectrally resampled hyperspectral narrowbands (HNBs). A two-step sparse partial least squares (SPLS) and linear discriminant analysis (LDA) was used for community separation. Results from Ivotuk were then used to predict community membership at five other sites along the Dalton Highway in Arctic Alaska. Overall classification accuracy at Ivotuk ranged from 84%-94% and from 55%-91% for the Dalton Highway test sites. The results of this study suggest that hyperspectral data acquired at the field level, along with the SPLS and LDA methodology, can be used to successfully discriminate among Arctic tundra vegetation communities in Alaska, and present an improvement over broad-band, coarse-scale methods for community classification.

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Section: Introductionmentioning

confidence: 95%

Section: Study Sitesmentioning

confidence: 99%

Section: Study Sitesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…Measurements were taken using an Analytical Spectral Devices FieldSpec spectro-radiometer. [17]. Measurements were taken using an Analytical Spectral Devices FieldSpec spectro-radiometer.…”

Section: Introductionmentioning

confidence: 99%

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Differentiating among Four Arctic Tundra Plant Communities at Ivotuk, Alaska Using Field Spectroscopy

et al. 2016

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Quantifying the Effects of Snowpack on Soil Thermal and Carbon Dynamics of the Arctic Terrestrial Ecosystems

Lyu

Zhuang

2018

JGR Biogeosciences

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Snow insulation effects modify soil and carbon dynamics in northern middle to high latitudes (45°–90°N). This study incorporates these effects by introducing a snow model into an existing soil thermal model in a biogeochemistry modeling framework, the Terrestrial Ecosystem Model. The coupled model is used to quantify snow insulation effects on carbon and soil thermal dynamics in 45°–90°N region for the historical period (2003–2010) and the future period (2017–2099) under two climate scenarios. The revised model captures the snow insulation effects and improves the estimates of soil thermal dynamics and the land freeze‐thaw as well as terrestrial ecosystem carbon dynamics. Historical mean cold‐season soil temperature at 5 cm depth driven with satellite‐based snow data is 6.4°C warmer in comparison with the original model simulation. Frozen area in late spring is estimated to shrink mainly over eastern Siberia, in central to eastern Europe, and along southern Canada in November. During each nongrowing season in the historical period, 0.41 Pg more soil C is released due to warmer soil temperature estimated using the new model. During 2003–2010, the revised model estimates that the region accumulated 0.86 Pg less C due to weaker gross primary production, leading to a regional C loss at 0.19 PgC/year. The revised model projects that the region will lose 38–51% permafrost area by 2100 and continue to be a C source under the low‐emission scenario (Representative Concentration Pathway 2.6) but to be gradually transitioning into a weak sink in the latter half of the 21st century under the high‐emission scenario (Representative Concentration Pathway 8.5).

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Canopy reflectance models illustrate varying NDVI responses to change in high latitude ecosystems

Huemmrich

Zesati

Campbell

et al. 2021

Ecological Applications

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Multiyear trends in Normalized Difference Vegetation Index (NDVI) have been used as metrics of high latitude ecosystem change based on the assumption that NDVI change is associated with ecological change, generally as changes in green vegetation amount (green leaf area index [LAI] or plant cover). Further, no change in NDVI is often interpreted as no change in these variables. Three canopy reflectance models including linear mixture model, the SAIL (Scattering from Arbitrarily Inclined Leaves) model, and the GeoSail model were used to simulate scenarios representing high latitude landscape NDVI responses to changes in LAI and plant cover. The simulations showed inconsistent NDVI responses. Clear increases in NDVI are generally associated with increases in LAI and plant cover. At higher values of LAI, the change in NDVI per unit change in LAI decreases, with very little change in spruce forest NDVI where crown cover is >50% and at the tundra-taiga ecotone with transitions from shrub tundra to spruce woodland. These lower responses may bias the interpretation of greening/ browning trends in boreal forests. Variations in water or snow coverage were shown to produce outsized nonbiological NDVI responses. Inconsistencies in NDVI responses exemplify the need for care in the interpretation of NDVI change as a metric of high latitude ecosystem change, and that landscape characteristics in terms of the type of cover and its characteristics, such as the initial plant cover, must be taken into account in evaluating the significance of any observed NDVI trends.

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Spatial and Temporal Heterogeneity of Vegetation Properties among Four Tundra Plant Communities at Ivotuk, Alaska, U.S.A

Cited by 44 publications

References 32 publications

Differentiating among Four Arctic Tundra Plant Communities at Ivotuk, Alaska Using Field Spectroscopy

Differentiating among Four Arctic Tundra Plant Communities at Ivotuk, Alaska Using Field Spectroscopy

Quantifying the Effects of Snowpack on Soil Thermal and Carbon Dynamics of the Arctic Terrestrial Ecosystems

Canopy reflectance models illustrate varying NDVI responses to change in high latitude ecosystems

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