An Ecological Land Survey for Fort Richardson, Alaska

Jorgenson, M. Torre; Roth, Joanna E.; Schlentner, Sharon F.; Pullman, Erik R.; Macander, Matt

doi:10.21236/ada417494

Cited by 41 publications

(94 citation statements)

References 18 publications

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“…The vegetation in the permafrost transition zone ranges from wetland tundra in the coastal area to the shrub tundra of vegetation subzone E [51] in the river deltas and valleys, to boreal forest in the eastern portion of the study area [65]. The land cover generally is dominated by low tundra vegetation of vegetation subzones C, D, and E as well as surface water bodies [51].…”

Section: Alaska Kobuk-selawik Lowlands (Aks)mentioning

confidence: 99%

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Landsat-Based Trend Analysis of Lake Dynamics across Northern Permafrost Regions

et al. 2017

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Lakes are a ubiquitous landscape feature in northern permafrost regions. They have a strong impact on carbon, energy and water fluxes and can be quite responsive to climate change. The monitoring of lake change in northern high latitudes, at a sufficiently accurate spatial and temporal resolution, is crucial for understanding the underlying processes driving lake change. To date, lake change studies in permafrost regions were based on a variety of different sources, image acquisition periods and single snapshots, and localized analysis, which hinders the comparison of different regions. Here, we present a methodology based on machine-learning based classification of robust trends of multi-spectral indices of Landsat data (TM, ETM+, OLI) and object-based lake detection, to analyze and compare the individual, local and regional lake dynamics of four different study sites (Alaska North Slope, Western Alaska, Central Yakutia, Kolyma Lowland) in the northern permafrost zone from 1999 to 2014. Regional patterns of lake area change on the Alaska North Slope (−0.69%), Western Alaska (−2.82%), and Kolyma Lowland (−0.51%) largely include increases due to thermokarst lake expansion, but more dominant lake area losses due to catastrophic lake drainage events. In contrast, Central Yakutia showed a remarkable increase in lake area of 48.48%, likely resulting from warmer and wetter climate conditions over the latter half of the study period. Within all study regions, variability in lake dynamics was associated with differences in permafrost characteristics, landscape position (i.e., upland vs. lowland), and surface geology. With the global availability of Landsat data and a consistent methodology for processing the input data derived from robust trends of multi-spectral indices, we demonstrate a transferability, scalability and consistency of lake change analysis within the northern permafrost region.

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Section: Alaska Kobuk-selawik Lowlands (Aks)mentioning

confidence: 99%

Section: Alaska Kobuk-selawik Lowlands (Aks)mentioning

confidence: 99%

Landsat-Based Trend Analysis of Lake Dynamics across Northern Permafrost Regions

et al. 2017

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“…Field data were available for all but one study area (Kugachiak). At each plot, we collected data describing geomorphology, soils, vegetation, and disturbance following an ecological land survey (ELS) approach [27]; these data were useful for classifying and mapping geomorphic units, polygonal landforms, and vegetation. Geomorphic units refer to deposits of surficial materials that are the result of geomorphic, ecological, and periglacial processes and were classified according to a system developed for Alaska [28].…”

Section: Field Observations and Terrain Mappingmentioning

confidence: 99%

Regional Patterns and Asynchronous Onset of Ice-Wedge Degradation since the Mid-20th Century in Arctic Alaska

Frost

Christopherson

Jorgenson³

et al. 2018

Remote Sensing

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Ice-wedge polygons are widespread and conspicuous surficial expressions of ground-ice in permafrost landscapes. Thawing of ice wedges triggers differential ground subsidence, local ponding, and persistent changes to vegetation and hydrologic connectivity across the landscape. Here we characterize spatio-temporal patterns of ice-wedge degradation since circa 1950 across environmental gradients on Alaska's North Slope. We used a spectral thresholding approach validated by field observations to map flooded thaw pits in high-resolution images from circa 1950, 1982, and 2012 for 11 study areas (1577-4460 ha). The total area of flooded pits increased since 1950 at 8 of 11 study areas (median change +3.6 ha; 130.3%). There were strong regional differences in the timing and extent of degradation; flooded pits were already extensive by 1950 on the Chukchi coastal plain (alluvial-marine deposits) and subsequent changes there indicate pit stabilization. Degradation began more recently on the central Beaufort coastal plain (eolian sand) and Arctic foothills (yedoma). Our results indicate that ice-wedge degradation in northern Alaska cannot be explained by late-20th century warmth alone. Likely mechanisms for asynchronous onset include landscape-scale differences in surficial materials and ground-ice content, regional climate gradients from west (maritime) to east (continental), and regional differences in the timing and magnitude of extreme warm summers after the Little Ice Age.

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“…Permafrost classes range from continuous to absent. Data sources for permafrost are varied with the majority from Jorgenson et al (2008) and from the fine scale maps of the Department of Defense Tanana Flats and Yukon Training areas in Jorgenson et al (1999). The spatial distribution of permafrost outside of the Tanana Flats and Yukon Training areas is not well mapped and is largely uncertain.…”

Section: Climatic and Physiographic Settingmentioning

confidence: 99%

“…The ice contents of the birch forest vary widely and can reach greater than 50% while ice contents are closer to 20% in the black spruce stands (Osterkamp et al, 2000). Groundwater upwelling, ultimately sourced from the Alaska Range to the south, results in a matrix of nutrient-rich fens where permafrost is absent ( Jorgenson et al, 1999). The fens are dominated by sedges and brown mosses (Table 2).…”

Section: Figurementioning

confidence: 99%

Sources and sinks of carbon in boreal ecosystems of interior Alaska: A review

Douglas

Jones

Hiemstra

et al. 2014

Elementa: Science of the Anthropocene

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Boreal ecosystems store large quantities of carbon but are increasingly vulnerable to carbon loss due to disturbance and climate warming. The boreal region in Alaska and Canada, largely underlain by discontinuous permafrost, presents a challenging landscape for itemizing carbon sources and sinks in soil and vegetation. The roles of fire, forest succession, and the presence (or absence) of permafrost on carbon cycle, vegetation, and hydrologic processes have been the focus of multidisciplinary research in boreal ecosystems for the past 20 years. However, projections of a warming future climate, an increase in fire severity and extent, and the potential degradation of permafrost could lead to major landscape and carbon cycle changes over the next 20 to 50 years. To assist land managers in interior Alaska in adapting and managing for potential changes in the carbon cycle we developed this review paper by incorporating an overview of the climate, ecosystem processes, vegetation, and soil regimes. Our objective is to provide a synthesis of the most current carbon storage estimates and measurements to guide policy and land management decisions on how to best manage carbon sources and sinks. We surveyed estimates of aboveground and belowground carbon stocks for interior Alaska boreal ecosystems and summarized methane and carbon dioxide f luxes. These data have been converted into similar units to facilitate comparison across ecosystem compartments. We identify potential changes in the carbon cycle with climate change and human disturbance. A novel research question is how compounding disturbances affect carbon sources and sinks associated with boreal ecosystem processes. Finally, we provide recommendations to address the challenges facing land managers in efforts to manage carbon cycle processes. The results of this study can be used for carbon cycle management in other locations within the boreal biome which encompasses a broad distribution from 45° to 83° north.

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An Ecological Land Survey for Fort Richardson, Alaska

Cited by 41 publications

References 18 publications

Landsat-Based Trend Analysis of Lake Dynamics across Northern Permafrost Regions

Landsat-Based Trend Analysis of Lake Dynamics across Northern Permafrost Regions

Regional Patterns and Asynchronous Onset of Ice-Wedge Degradation since the Mid-20th Century in Arctic Alaska

Sources and sinks of carbon in boreal ecosystems of interior Alaska: A review

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