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Title: Historical and Projected Trends in Landscape Drivers Affecting Carbon Dynamics in Alaska

Modern climate change in Alaska has resulted in widespread thawing of permafrost, increased fire activity, and extensive changes in vegetation characteristics that have significant consequences for socio-ecological systems. Despite observations of the heightened sensitivity of these systems to change, there has not been a comprehensive assessment of factors that drive ecosystem changes throughout Alaska. In this paper, we present research that improves our understanding of the main drivers of the spatiotemporal patterns of carbon dynamics using in situ observations, remote sensing data, and an array of modeling techniques. In the last 60 years, Alaska has seen a large increase in mean annual air temperature (1.7 °C), with the greatest warming occurring over winter and spring. Warming trends are projected to continue throughout the 21st century and will likely result in landscape-level changes to ecosystem structure and function. Wetlands, mainly bogs and fens, which are currently estimated to cover 12.5% of the landscape, strongly influence exchange of methane between Alaska's ecosystems and the atmosphere and are expected to be affected by thawing permafrost and shifts in hydrology. Simulations suggest the current proportion of near-surface (within 1 m) and deep (within 5 m) permafrost extent will be reduced by 9–74% and 33–55%more » by the end of the 21st century, respectively. Since 2000, an average of 678,595 ha/yr was burned, more than twice the annual average during 1950–1999. The largest increase in fire activity is projected for the boreal forest, which could result in a reduction in late-successional spruce forest (8–44%) and an increase in early-succession deciduous forest (25–113%) that would mediate future fire activity and weaken permafrost stability in the region. Climate warming will also affect vegetation communities across arctic regions, where the coverage of deciduous forest could increase (223–620%), shrub tundra may increase (4–21%), and graminoid tundra might decrease (10–24%). Finally, this study sheds light on the sensitivity of Alaska's ecosystems to change that has the potential to significantly affect local and regional carbon balance, but more research is needed to improve estimates of land-surface and subsurface properties, and to better account for ecosystem dynamics affected by a myriad of biophysical factors and interactions.« less
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [6] ;  [7] ;  [8] ;  [9] ;  [10] ;  [11]
  1. Stinger Ghaffarian Technologies, Inc., Sioux Falls, SD (United States). Contractor of U.S. Geological Survey; Univ. of Minnesota, St. Paul, MN (United States). Dept. of Forest Resources
  2. Neptune and Company, Inc., Lakewood, CO (United States)
  3. Univ. of Alaska, Fairbanks, AK (United States). Inst. of Arctic Biology
  4. Univ. of Alaska, Fairbanks, AK (United States). International Arctic Research Center. Scenarios Network for Alaska and Arctic Planning
  5. U.S. Geological Survey, Sioux Falls, SD (United States). Earth Resources Observation and Science Center
  6. US Dept. of Agriculture (USDA) Forest Service, Newtown Square, PA (United States). Northern Research Station
  7. Alaska Ecoscience, Fairbanks, AK (United States)
  8. ASRC Federal InuTeq, Sioux Falls, SD (United States). Contractor of U.S. Geological Survey
  9. Univ. of Alaska, Fairbanks, AK (United States). U.S. Geological Survey. Alaska Cooperative Fish and Wildlife Research Unit
  10. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  11. Univ. of Minnesota, St. Paul, MN (United States). Dept. of Forest Resources
Publication Date:
Report Number(s):
LA-UR-17-23048
Journal ID: ISSN 1051-0761
Grant/Contract Number:
AC52-06NA25396; G10AC00588; G08PC91508
Type:
Accepted Manuscript
Journal Name:
Ecological Applications
Additional Journal Information:
Journal Volume: 27; Journal Issue: 5; Journal ID: ISSN 1051-0761
Publisher:
Ecological Society of America
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE; United States Geological Survey (USGS); National Aeronautic and Space Administration (NASA); Dept. of the Interior (DOI) (United States)
Contributing Orgs:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Stinger Ghaffarian Technologies, Inc., Sioux Falls, SD (United States); Univ. of Minnesota, St. Paul, MN (United States); Neptune and Company, Inc., Lakewood, CO (United States); US Dept. of Agriculture (USDA) Forest Service, Newtown Square, PA (United States); Alaska Ecoscience, Fairbanks, AK (United States); ASRC Federal InuTeq, Sioux Falls, SD (United States)
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; Earth Sciences; Alaska; boreal forest; climate change; carbon dynamics; permafrost
OSTI Identifier:
1356157