SwePub
Sök i SwePub databas

  Utökad sökning

Träfflista för sökning "WFRF:(Johnstone Jill F.) "

Sökning: WFRF:(Johnstone Jill F.)

  • Resultat 1-6 av 6
Sortera/gruppera träfflistan
   
NumreringReferensOmslagsbildHitta
1.
  • Abbott, Benjamin W., et al. (författare)
  • Biomass offsets little or none of permafrost carbon release from soils, streams, and wildfire : an expert assessment
  • 2016
  • Ingår i: Environmental Research Letters. - : IOP Publishing: Open Access Journals / IOP Publishing. - 1748-9326 .- 1748-9326. ; 11:3
  • Tidskriftsartikel (refereegranskat)abstract
    • As the permafrost region warms, its large organic carbon pool will be increasingly vulnerable to decomposition, combustion, and hydrologic export. Models predict that some portion of this release will be offset by increased production of Arctic and boreal biomass; however, the lack of robust estimates of net carbon balance increases the risk of further overshooting international emissions targets. Precise empirical or model-based assessments of the critical factors driving carbon balance are unlikely in the near future, so to address this gap, we present estimates from 98 permafrost-region experts of the response of biomass, wildfire, and hydrologic carbon flux to climate change. Results suggest that contrary to model projections, total permafrost-region biomass could decrease due to water stress and disturbance, factors that are not adequately incorporated in current models. Assessments indicate that end-of-the-century organic carbon release from Arctic rivers and collapsing coastlines could increase by 75% while carbon loss via burning could increase four-fold. Experts identified water balance, shifts in vegetation community, and permafrost degradation as the key sources of uncertainty in predicting future system response. In combination with previous findings, results suggest the permafrost region will become a carbon source to the atmosphere by 2100 regardless of warming scenario but that 65%-85% of permafrost carbon release can still be avoided if human emissions are actively reduced.
  •  
2.
  • Bjorkman, Anne D., et al. (författare)
  • Plant functional trait change across a warming tundra biome
  • Ingår i: Nature. - : Nature Publishing Group. - 0028-0836 .- 1476-4687. ; 562:7725, s. 57-62
  • Tidskriftsartikel (refereegranskat)abstract
    • The tundra is warming more rapidly than any other biome on Earth, and the potential ramifications are far-reaching because of global feedback effects between vegetation and climate. A better understanding of how environmental factors shape plant structure and function is crucial for predicting the consequences of environmental change for ecosystem functioning. Here we explore the biome-wide relationships between temperature, moisture and seven key plant functional traits both across space and over three decades of warming at 117 tundra locations. Spatial temperature–trait relationships were generally strong but soil moisture had a marked influence on the strength and direction of these relationships, highlighting the potentially important influence of changes in water availability on future trait shifts in tundra plant communities. Community height increased with warming across all sites over the past three decades, but other traits lagged far behind predicted rates of change. Our findings highlight the challenge of using space-for-time substitution to predict the functional consequences of future warming and suggest that functions that are tied closely to plant height will experience the most rapid change. They also reveal the strength with which environmental factors shape biotic communities at the coldest extremes of the planet and will help to improve projections of functional changes in tundra ecosystems with climate warming.
  •  
3.
  • Elmendorf, Sarah C., et al. (författare)
  • Plot-scale evidence of tundra vegetation change and links to recent summer warming
  • 2012
  • Ingår i: Nature Climate Change. - : Nature Publishing Group. - 1758-678X .- 1758-6798. ; 2:6, s. 453-457
  • Tidskriftsartikel (refereegranskat)abstract
    • Temperature is increasing at unprecedented rates across most of the tundra biome. Remote-sensing data indicate that contemporary climate warming has already resulted in increased productivity over much of the Arctic, but plot-based evidence for vegetation transformation is not widespread. We analysed change in tundra vegetation surveyed between 1980 and 2010 in 158 plant communities spread across 46 locations.We found biome-wide trends of increased height of the plant canopy and maximum observed plant height for most vascular growth forms; increased abundance of litter; increased abundance of evergreen, low-growing and tall shrubs; and decreased abundance of bare ground. Intersite comparisons indicated an association between the degree of summer warming and change in vascular plant abundance, with shrubs, forbs and rushes increasing with warming. However, the association was dependent on the climate zone, the moisture regime and the presence of permafrost. Our data provide plot-scale evidence linking changes in vascular plant abundance to local summer warming in widely dispersed tundra locations across the globe.
  •  
4.
  •  
5.
  • Bjorkman, Anne, 1981, et al. (författare)
  • Tundra Trait Team: A database of plant traits spanning the tundra biome
  • 2018
  • Ingår i: Global Ecology and Biogeography. - : John Wiley & Sons. - 1466-822X .- 1466-8238. ; 27:12, s. 1402-1411
  • Tidskriftsartikel (refereegranskat)abstract
    • © 2018 The Authors Global Ecology and Biogeography Published by John Wiley & Sons Ltd Motivation: The Tundra Trait Team (TTT) database includes field-based measurements of key traits related to plant form and function at multiple sites across the tundra biome. This dataset can be used to address theoretical questions about plant strategy and trade-offs, trait–environment relationships and environmental filtering, and trait variation across spatial scales, to validate satellite data, and to inform Earth system model parameters. Main types of variable contained: The database contains 91,970 measurements of 18 plant traits. The most frequently measured traits (> 1,000 observations each) include plant height, leaf area, specific leaf area, leaf fresh and dry mass, leaf dry matter content, leaf nitrogen, carbon and phosphorus content, leaf C:N and N:P, seed mass, and stem specific density. Spatial location and grain: Measurements were collected in tundra habitats in both the Northern and Southern Hemispheres, including Arctic sites in Alaska, Canada, Greenland, Fennoscandia and Siberia, alpine sites in the European Alps, Colorado Rockies, Caucasus, Ural Mountains, Pyrenees, Australian Alps, and Central Otago Mountains (New Zealand), and sub-Antarctic Marion Island. More than 99% of observations are georeferenced. Time period and grain: All data were collected between 1964 and 2018. A small number of sites have repeated trait measurements at two or more time periods. Major taxa and level of measurement: Trait measurements were made on 978 terrestrial vascular plant species growing in tundra habitats. Most observations are on individuals (86%), while the remainder represent plot or site means or maximums per species. Software format: csv file and GitHub repository with data cleaning scripts in R; contribution to TRY plant trait database (www.try-db.org) to be included in the next version release.
  •  
6.
  • Callaghan, Terry V., et al. (författare)
  • Multi-Decadal Changes in Tundra Environments and Ecosystems: Synthesis of the International Polar Year-Back to the Future Project (IPY-BTF)
  • 2011
  • Ingår i: Ambio: a Journal of Human Environment. - : Springer. - 0044-7447 .- 1654-7209. ; 40:6, s. 705-716
  • Tidskriftsartikel (refereegranskat)abstract
    • Understanding the responses of tundra systems to global change has global implications. Most tundra regions lack sustained environmental monitoring and one of the only ways to document multi-decadal change is to resample historic research sites. The International Polar Year (IPY) provided a unique opportunity for such research through the Back to the Future (BTF) project (IPY project #512). This article synthesizes the results from 13 papers within this Ambio Special Issue. Abiotic changes include glacial recession in the Altai Mountains, Russia; increased snow depth and hardness, permafrost warming, and increased growing season length in sub-arctic Sweden; drying of ponds in Greenland; increased nutrient availability in Alaskan tundra ponds, and warming at most locations studied. Biotic changes ranged from relatively minor plant community change at two sites in Greenland to moderate change in the Yukon, and to dramatic increases in shrub and tree density on Herschel Island, and in sub-arctic Sweden. The population of geese tripled at one site in northeast Greenland where biomass in non-grazed plots doubled. A model parameterized using results from a BTF study forecasts substantial declines in all snowbeds and increases in shrub tundra on Niwot Ridge, Colorado over the next century. In general, results support and provide improved capacities for validating experimental manipulation, remote sensing, and modeling studies.
  •  
Skapa referenser, mejla, bekava och länka
  • Resultat 1-6 av 6
Typ av publikation
tidskriftsartikel (6)
Typ av innehåll
refereegranskat (6)
Författare/redaktör
Lévesque, Esther (6)
Johnstone, Jill F. (5)
Oberbauer, Steven F. (5)
Myers-Smith, Isla H. (5)
Michelsen, Anders (4)
Heijmans, Monique M. ... (4)
visa fler...
Hik, David S. (4)
Tremblay, Jean-Pierr ... (4)
Christensen, Torben ... (3)
Cornelissen, J. Hans ... (3)
Dorrepaal, Ellen (3)
Forbes, Bruce C. (3)
Grogan, Paul (3)
Molau, Ulf (3)
Welker, Jeffrey M. (3)
Hofgaard, Annika (3)
Diaz, Sandra (2)
Chapin, F. Stuart, I ... (2)
Mack, Michelle C. (2)
Alexander, Heather D ... (2)
Goetz, Scott J. (2)
Keuper, Frida (2)
Chapin, F. Stuart (2)
Hedenås, Henrik (2)
Björk, Robert G. (2)
Alatalo, Juha M. (2)
Molau, Ulf, 1951 (2)
Little, Chelsea J. (2)
Åkerman, Jonas (2)
Grau, Oriol (2)
Elberling, Bo (2)
Björk, Robert G., 19 ... (2)
Klanderud, Kari (2)
Niinemets, Ulo (2)
Olofsson, Johan (2)
Soudzilovskaia, Nade ... (2)
Te Beest, Mariska (2)
Buchwal, Agata (2)
Hallinger, Martin (2)
Jónsdóttir, Ingibjor ... (2)
Kaarlejärvi, Elina (2)
Normand, Signe (2)
Speed, James D. M. (2)
Street, Lorna E. (2)
Wilmking, Martin (2)
Milbau, Ann (2)
Schaepman-Strub, Gab ... (2)
Blok, Daan (2)
Hajek, Tomas (2)
Bjorkman, Anne D. (2)
visa färre...
Lärosäte
Göteborgs universitet (3)
Umeå universitet (3)
Lunds universitet (3)
Stockholms universitet (1)
Sveriges Lantbruksuniversitet (1)
Språk
Engelska (6)
Forskningsämne (UKÄ/SCB)
Naturvetenskap (6)
Lantbruksvetenskap (2)

År

 
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy