Changes in Alaskan Tundra Ecosystems Estimated from MODIS Greenness Trends, 2000 to 2010

2013 ◽  
Vol 02 (01) ◽  
Author(s):  
Christopher Potter Shuang Li
Keyword(s):  
Alaskan Tundra ◽  
Tundra Ecosystems

Sedimentary charcoal proxy records of fire in Alaskan tundra ecosystems

2020 ◽  
Vol 541 ◽  
pp. 109564 ◽  
Author(s):  
Richard S. Vachula ◽  
Jarunetr Sae-Lim ◽  
James M. Russell
Keyword(s):  
Proxy Records ◽  
Alaskan Tundra ◽  
Tundra Ecosystems

The morphology of experimentally produced charcoal distinguishes fuel types in the Arctic tundra

The Holocene ◽  
2020 ◽  
Vol 30 (7) ◽  
pp. 1091-1096 ◽  
Author(s):  
Eleanor MB Pereboom ◽  
Richard S Vachula ◽  
Yongsong Huang ◽  
James Russell
Keyword(s):  
Arctic Tundra ◽  
Global Carbon Cycle ◽  
Fire Frequency ◽  
The Arctic ◽  
Fuel Type ◽  
The Past ◽  
Primary Means ◽  
Forested Ecosystems ◽  
Global Carbon ◽  
Tundra Ecosystems

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.

Comparison of Radiocesium in Alaskan Tundra Plants, 1961 and 1971

1975 ◽  
Vol 7 (3) ◽  
pp. 285
Author(s):  
W. H. Rickard ◽  
J. D. Hedlund ◽  
H. A. Sweany
Keyword(s):  
Alaskan Tundra

Effects of CO2 enrichment and nutrition on growth, photosynthesis, and nutrient concentration of Alaskan tundra plant species

1986 ◽  
Vol 64 (12) ◽  
pp. 2993-2998 ◽  
Author(s):  
Steven F. Oberbauer ◽  
Nasser Sionit ◽  
Steven J. Hastings ◽  
Walter C. Oechel
Keyword(s):  
Plant Biomass ◽  
Co2 Enrichment ◽  
Nutrient Content ◽  
Interactive Effects ◽  
Photon Flux ◽  
Nutrient Concentrations ◽  
Total Biomass ◽  
Ledum Palustre ◽  
Carbon Dioxide Concentrations ◽  
Alaskan Tundra

Three Alaskan tundra species, Carex bigelowii Torr., Betula nana L., and Ledum palustre L., were grown in controlled-environment chambers at two nutrition levels with two concentrations of atmospheric CO2 to assess the interactive effects of these factors on growth, photosynthesis, and tissue nutrient content. Carbon dioxide concentrations were maintained at 350 and 675 μL L−1 under photosynthetic photon flux densities of 450 μmol m−2 s−1 and temperatures of 20:15 °C (light:dark). Nutrient treatments were obtained by watering daily with 1/60- or 1/8- strength Hoagland's solution. Leaf, root, and total biomass were strongly enhanced by nutrient enrichment regardless of the CO2 concentration. In contrast, enriched atmospheric CO2 did not significantly affect plant biomass and there was no interaction between nutrition and CO2 concentration during growth. Leaf photosynthesis was increased by better nutrition in two species but was unchanged by CO2 enrichment during growth in all three species. The effects of nutrient addition and CO2 enrichment on tissue nutrient concentrations were complex and differed among the three species. The data suggest that CO2 enrichment with or without nutrient limitation has little effect on the biomass production of these three tundra species.

scholarly journals Climate Drivers Linked to Changing Seasonality of Alaska Coastal Tundra Vegetation Productivity

2015 ◽  
Vol 19 (19) ◽  
pp. 1-29 ◽  
Author(s):  
Peter A. Bieniek ◽  
Uma S. Bhatt ◽  
Donald A. Walker ◽  
Martha K. Raynolds ◽  
Josefino C. Comiso ◽  
...  
Keyword(s):  
Land Surface ◽  
Large Scale ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Sea Breeze ◽  
Tundra Vegetation ◽  
Land Surface Temperatures ◽  
Alaskan Tundra ◽  
Northern Alaska

Abstract The mechanisms driving trends and variability of the normalized difference vegetation index (NDVI) for tundra in Alaska along the Beaufort, east Chukchi, and east Bering Seas for 1982–2013 are evaluated in the context of remote sensing, reanalysis, and meteorological station data as well as regional modeling. Over the entire season the tundra vegetation continues to green; however, biweekly NDVI has declined during the early part of the growing season in all of the Alaskan tundra domains. These springtime declines coincide with increased snow depth in spring documented in northern Alaska. The tundra region generally has warmed over the summer but intraseasonal analysis shows a decline in midsummer land surface temperatures. The midsummer cooling is consistent with recent large-scale circulation changes characterized by lower sea level pressures, which favor increased cloud cover. In northern Alaska, the sea-breeze circulation is strengthened with an increase in atmospheric moisture/cloudiness inland when the land surface is warmed in a regional model, suggesting the potential for increased vegetation to feedback onto the atmospheric circulation that could reduce midsummer temperatures. This study shows that both large- and local-scale climate drivers likely play a role in the observed seasonality of NDVI trends.

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