Snow-mediated ptarmigan browsing and shrub expansion in arctic Alaska

Ecoscience ◽  
2010 ◽  
Vol 17 (2) ◽  
pp. 186-193 ◽  
Author(s):  
Ken D. Tape ◽  
Rachel Lord ◽  
Hans-Peter Marshall ◽  
Roger W. Ruess
Keyword(s):  
Shrub Expansion ◽  
Arctic Alaska

Landscape Heterogeneity of Shrub Expansion in Arctic Alaska

Ecosystems ◽  
2012 ◽  
Vol 15 (5) ◽  
pp. 711-724 ◽  
Author(s):  
Ken D. Tape ◽  
Martin Hallinger ◽  
Jeffrey M. Welker ◽  
Roger W. Ruess
Keyword(s):  
Landscape Heterogeneity ◽  
Shrub Expansion ◽  
Arctic Alaska

Patterns and processes of global shrub expansion

2011 ◽  
Vol 35 (4) ◽  
pp. 423-442 ◽  
Author(s):  
Adam T. Naito ◽  
David M. Cairns
Keyword(s):  
Simulation Modeling ◽  
Satellite Remote Sensing ◽  
Aerial Photograph ◽  
The Arctic ◽  
Shrub Expansion ◽  
Global Land ◽  
Technological Developments ◽  
Management Policies ◽  
Patterns And Processes ◽  
Land Types

Shrub expansion is a global phenomenon that is occurring on savannas, rangelands, and grasslands. In addition, this is an increasingly documented occurrence in the Arctic. Numerous recent studies have strived to pinpoint the drivers of this phenomenon, quantify the changes, and understand their implications for regional and global land use, disturbance regimes, and nutrient cycling. Inquiry into these topics has been facilitated by recent technological developments in satellite remote sensing, aerial photograph analysis, and computer simulation modeling. We provide a new review that accounts for more recent studies in these regions, Arctic shrub expansion, and technological and analytical developments. This four-part discussion focuses on observed patterns of shrub expansion in three rangeland types (desert grasslands, mesic grasslands, savannas) and the Arctic tundra, the primary causes of this expansion, critical comparisons and contrasts between these land types, and recommendations for future avenues of research. These new avenues can inform the development of future land management policies, as well as ongoing investigations to understand and mitigate the effects of climate change.

scholarly journals Investigating the morphological and genetic divergence of arctic char ( Salvelinus alpinus) populations in lakes of arctic Alaska

2021 ◽  
Author(s):  
Stephen L. Klobucar ◽  
Jessica A. Rick ◽  
Elizabeth G. Mandeville ◽  
Catherine E. Wagner ◽  
Phaedra Budy
Keyword(s):  
Genetic Divergence ◽  
Salvelinus Alpinus ◽  
Arctic Char ◽  
Arctic Alaska

A Precolumbian Presence of Venetian Glass Trade Beads in Arctic Alaska

2021 ◽  
pp. 1-18
Author(s):  
Michael L. Kunz ◽  
Robin O. Mills
Keyword(s):  
Neutron Activation Analysis ◽  
Instrumental Neutron Activation Analysis ◽  
Western Hemisphere ◽  
Eastern Coast ◽  
Great Lakes Region ◽  
Late Prehistoric ◽  
Bering Strait ◽  
Eurasian Continent ◽  
Arctic Alaska ◽  
The Caribbean

Excavation at three Late Prehistoric Eskimo sites in arctic Alaska has revealed the presence of Venetian glass trade beads in radiocarbon-dated contexts that predate Columbus's discovery of the Western Hemisphere. The bead variety, commonly known as “Early Blue” and “Ichtucknee Plain,” has been confirmed by expert examination and comparative Instrumental Neutron Activation Analysis (INAA). The beads are present in sites throughout the Caribbean, the eastern coast of Central and North America, and the eastern Great Lakes region, where they are commonly found in sites dating between approximately AD 1550 and 1750, although a diminishing presence continues into the early 1800s. Beads of this variety have not previously been reported from Alaska. Ascribed to Venetian production by their precolumbian age, the beads challenge the currently accepted chronology for the development of their production methodology, availability, and presence in the Americas. In the absence of trans-Atlantic communication, the most likely route these beads traveled from Europe to northwestern Alaska is across Eurasia and over the Bering Strait. This is the first documented instance of the presence of indubitable European materials in prehistoric sites in the Western Hemisphere as the result of overland transport across the Eurasian continent.

scholarly journals Arctic riparian shrub expansion indicates a shift from streams gaining water to those that lose flow

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Anna K. Liljedahl ◽  
Ina Timling ◽  
Gerald V. Frost ◽  
Ronald P. Daanen
Keyword(s):  
Microbial Communities ◽  
Soil Microbial Communities ◽  
Late Summer ◽  
Field Measurements ◽  
The Arctic ◽  
Shrub Expansion ◽  
Riparian Ecosystems ◽  
Stream Length ◽  
Area Index ◽  
Soil Microbial

AbstractShrub expansion has been observed across the Arctic in recent decades along with warming air temperatures, but tundra shrub expansion has been most pronounced in protected landscape positions such as floodplains, streambanks, water tracks, and gullies. Here we show through field measurements and laboratory analyses how stream hydrology, permafrost, and soil microbial communities differed between streams in late summer with and without tall shrubs. Our goal was to assess the causes and consequences of tall shrub expansion in Arctic riparian ecosystems. Our results from Toolik Alaska, show greater canopy height and density, and distinctive plant and soil microbial communities along stream sections that lose water into unfrozen ground (talik) compared to gaining sections underlain by shallow permafrost. Leaf Area Index is linearly related to the change in streamflow per unit stream length, with the densest canopies coinciding with increasingly losing stream sections. Considering climate change and the circumpolar scale of riparian shrub expansion, we suggest that permafrost thaw and the resulting talik formation and shift in streamflow regime are occurring across the Low Arctic.

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