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Your search keyword '"Epstein, Howard E"' showing total 13 results
Start Over Author "Epstein, Howard E" Journal environmental research letters
13 results on '"Epstein, Howard E"'

1. Changing Seasonality of Panarctic Tundra Vegetation in Relationship to Climatic Variables

Author

Bhatt, Uma S, Walker, Donald A, Raynolds, Martha K, Bieniek, Peter A, Epstein, Howard E, Comiso, Josefino C, Pinzon, Jorge E, Tucker, Compton J, Steele, Michael, Ermold, Wendy, and Zhang, Jinlun

Subjects
Geosciences (General)
Abstract

Potential climate drivers of Arctic tundra vegetation productivity are investigated to understand recent greening and browning trends documented by maximum normalized difference vegetation index (NDVI) (MaxNDVI) and time-integrated NDVI (TI-NDVI) for 19822015. Over this period, summer sea ice has continued to decline while oceanic heat content has increased. The increases in summer warmth index (SWI) and NDVI have not been uniform over the satellite record. SWI increased from 1982 to the mid-1990s and remained relatively flat from 1998 onwards until a recent upturn. While MaxNDVI displays positive trends from 19822015, TI-NDVI increased from 1982 until 2001 and has declined since. The data for the first and second halves of the record were analyzed and compared spatially for changing trends with a focus on the growing season. Negative trends for MaxNDVI and TI-NDVI were more common during 19992015 compared to 19821998.

Published
2017
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2. Climate drivers of Arctic tundra variability and change using an indicators framework

Author

Bhatt, Uma S, primary, Walker, Donald A, additional, Raynolds, Martha K, additional, Walsh, John E, additional, Bieniek, Peter A, additional, Cai, Lei, additional, Comiso, Josefino C, additional, Epstein, Howard E, additional, Frost, Gerald V, additional, Gersten, Robert, additional, Hendricks, Amy S, additional, Pinzon, Jorge E, additional, Stock, Larry, additional, and Tucker, Compton J, additional

Published
2021
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3. Spatial patterns of arctic tundra vegetation properties on different soils along the Eurasia Arctic Transect, and insights for a changing Arctic

Author

Epstein, Howard E, primary, Walker, Donald A, additional, Frost, Gerald V, additional, Raynolds, Martha K, additional, Bhatt, Uma, additional, Daanen, Ronald, additional, Forbes, Bruce, additional, Geml, Jozsef, additional, Kaärlejarvi, Elina, additional, Khitun, Olga, additional, Khomutov, Artem, additional, Kuss, Patrick, additional, Leibman, Marina, additional, Matyshak, Georgy, additional, Moskalenko, Nataliya, additional, Orekhov, Pavel, additional, Romanovsky, Vladimir E, additional, and Timling, Ina, additional

Published
2020
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4. Shallow soils are warmer under trees and tall shrubs across Arctic and Boreal ecosystems

Author

Kropp, Heather, primary, Loranty, Michael M, additional, Natali, Susan M, additional, Kholodov, Alexander L, additional, Rocha, Adrian V, additional, Myers-Smith, Isla, additional, Abbot, Benjamin W, additional, Abermann, Jakob, additional, Blanc-Betes, Elena, additional, Blok, Daan, additional, Blume-Werry, Gesche, additional, Boike, Julia, additional, Breen, Amy L, additional, Cahoon, Sean M P, additional, Christiansen, Casper T, additional, Douglas, Thomas A, additional, Epstein, Howard E, additional, Frost, Gerald V, additional, Goeckede, Mathias, additional, Høye, Toke T, additional, Mamet, Steven D, additional, O’Donnell, Jonathan A, additional, Olefeldt, David, additional, Phoenix, Gareth K, additional, Salmon, Verity G, additional, Sannel, A Britta K, additional, Smith, Sharon L, additional, Sonnentag, Oliver, additional, Vaughn, Lydia Smith, additional, Williams, Mathew, additional, Elberling, Bo, additional, Gough, Laura, additional, Hjort, Jan, additional, Lafleur, Peter M, additional, Euskirchen, Eugenie S, additional, Heijmans, Monique MPD, additional, Humphreys, Elyn R, additional, Iwata, Hiroki, additional, Jones, Benjamin M, additional, Jorgenson, M Torre, additional, Grünberg, Inge, additional, Kim, Yongwon, additional, Laundre, James, additional, Mauritz, Marguerite, additional, Michelsen, Anders, additional, Schaepman-Strub, Gabriela, additional, Tape, Ken D, additional, Ueyama, Masahito, additional, Lee, Bang-Yong, additional, Langley, Kirsty, additional, and Lund, Magnus, additional

Published
2020
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5. Dynamics of Aboveground Phytomass of the Circumpolar Arctic Tundra During the Past Three Decades

Author

Epstein, Howard E, Raynolds, Martha K, Walker, Donald A, Bhatt, Uma S, Tucker, Compton J, and Pinzon, Jorge E

Subjects
Earth Resources And Remote Sensing
Abstract

Numerous studies have evaluated the dynamics of Arctic tundra vegetation throughout the past few decades, using remotely sensed proxies of vegetation, such as the normalized difference vegetation index (NDVI). While extremely useful, these coarse-scale satellite-derived measurements give us minimal information with regard to how these changes are being expressed on the ground, in terms of tundra structure and function. In this analysis, we used a strong regression model between NDVI and aboveground tundra phytomass, developed from extensive field-harvested measurements of vegetation biomass, to estimate the biomass dynamics of the circumpolar Arctic tundra over the period of continuous satellite records (1982-2010). We found that the southernmost tundra subzones (C-E) dominate the increases in biomass, ranging from 20 to 26%, although there was a high degree of heterogeneity across regions, floristic provinces, and vegetation types. The estimated increase in carbon of the aboveground live vegetation of 0.40 Pg C over the past three decades is substantial, although quite small relative to anthropogenic C emissions. However, a 19.8% average increase in aboveground biomass has major implications for nearly all aspects of tundra ecosystems including hydrology, active layer depths, permafrost regimes, wildlife and human use of Arctic landscapes. While spatially extensive on-the-ground measurements of tundra biomass were conducted in the development of this analysis, validation is still impossible without more repeated, long-term monitoring of Arctic tundra biomass in the field.

Published
2012
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6. Spatial patterns of arctic tundra vegetation properties on different soils along the Eurasia Arctic Transect, and insights for a changing Arctic.

Author

Epstein, Howard E, Walker, Donald A, Frost, Gerald V, Raynolds, Martha K, Bhatt, Uma, Daanen, Ronald, Forbes, Bruce, Geml, Jozsef, Kaärlejarvi, Elina, Khitun, Olga, Khomutov, Artem, Kuss, Patrick, Leibman, Marina, Matyshak, Georgy, Moskalenko, Nataliya, Orekhov, Pavel, Romanovsky, Vladimir E, and Timling, Ina

Published
2021
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7. Shallow soils are warmer under trees and tall shrubs across Arctic and Boreal ecosystems.

Author

Kropp, Heather, Loranty, Michael M, Natali, Susan M, Kholodov, Alexander L, Rocha, Adrian V, Myers-Smith, Isla, Abbot, Benjamin W, Abermann, Jakob, Blanc-Betes, Elena, Blok, Daan, Blume-Werry, Gesche, Boike, Julia, Breen, Amy L, Cahoon, Sean M P, Christiansen, Casper T, Douglas, Thomas A, Epstein, Howard E, Frost, Gerald V, Goeckede, Mathias, and Hřye, Toke T

Published
2021
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12. Shrub expansion in tundra ecosystems: dynamics, impacts and research priorities

Author

Myers-Smith, Isla H, primary, Forbes, Bruce C, additional, Wilmking, Martin, additional, Hallinger, Martin, additional, Lantz, Trevor, additional, Blok, Daan, additional, Tape, Ken D, additional, Macias-Fauria, Marc, additional, Sass-Klaassen, Ute, additional, Lévesque, Esther, additional, Boudreau, Stéphane, additional, Ropars, Pascale, additional, Hermanutz, Luise, additional, Trant, Andrew, additional, Collier, Laura Siegwart, additional, Weijers, Stef, additional, Rozema, Jelte, additional, Rayback, Shelly A, additional, Schmidt, Niels Martin, additional, Schaepman-Strub, Gabriela, additional, Wipf, Sonja, additional, Rixen, Christian, additional, Ménard, Cécile B, additional, Venn, Susanna, additional, Goetz, Scott, additional, Andreu-Hayles, Laia, additional, Elmendorf, Sarah, additional, Ravolainen, Virve, additional, Welker, Jeffrey, additional, Grogan, Paul, additional, Epstein, Howard E, additional, and Hik, David S, additional

Published
2011
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13. Spatial patterns of arctic tundra vegetation properties on different soils along the Eurasia Arctic Transect, and insights for a changing Arctic

Author

Patrick Kuss, Olga Khitun, Vladimir E. Romanovsky, G. V. Matyshak, Pavel Orekhov, Artem Khomutov, Gerald V. Frost, Martha K. Raynolds, Bruce C. Forbes, Howard E. Epstein, Marina Leibman, József Geml, Ronald P. Daanen, Elina Kaarlejärvi, Ina Timling, Donald A. Walker, Nataliya G Moskalenko, Uma S. Bhatt, University of Zurich, Epstein, Howard E, Research Centre for Ecological Change, and Organismal and Evolutionary Biology Research Programme

Subjects
0106 biological sciences, 010504 meteorology & atmospheric sciences, 2105 Renewable Energy, Sustainability and the Environment, 580 Plants (Botany), 010603 evolutionary biology, 01 natural sciences, Normalized Difference Vegetation Index, 2300 General Environmental Science, Renewable Energy, 10211 Zurich-Basel Plant Science Center, Transect, 0105 earth and related environmental sciences, General Environmental Science, Sustainability and the Environment, Renewable Energy, Sustainability and the Environment, Environmental and Occupational Health, Public Health, Environmental and Occupational Health, 2739 Public Health, Environmental and Occupational Health, Vegetation, Vegetation biomass, 15. Life on land, Tundra, 10121 Department of Systematic and Evolutionary Botany, Arctic, 13. Climate action, 1181 Ecology, evolutionary biology, Soil water, Spatial ecology, Environmental science, Public Health, Physical geography
Abstract

Vegetation properties of arctic tundra vary dramatically across its full latitudinal extent, yet few studies have quantified tundra ecosystem properties across latitudinal gradients with field-based observations that can be related to remotely sensed proxies. Here we present data from field sampling of six locations along the Eurasia Arctic Transect in northwestern Siberia. We collected data on the aboveground vegetation biomass, the normalized difference vegetation index (NDVI), and the leaf area index (LAI) for both sandy and loamy soil types, and analyzed their spatial patterns. Aboveground biomass, NDVI, and LAI all increased with increasing summer warmth index (SWI—sum of monthly mean temperatures > 0 °C), although functions differed, as did sandy vs. loamy sites. Shrub biomass increased non-linearly with SWI, although shrub type biomass diverged with soil texture in the southernmost locations, with greater evergreen shrub biomass on sandy sites, and greater deciduous shrub biomass on loamy sites. Moss biomass peaked in the center of the gradient, whereas lichen biomass generally increased with SWI. Total aboveground biomass varied by two orders of magnitude, and shrubs increased from 0 g m−2 at the northernmost sites to >500 g m−2 at the forest-tundra ecotone. Current observations and estimates of increases in total aboveground and shrub biomass with climate warming in the Arctic fall short of what would represent a ‘subzonal shift’ based on our spatial data. Non-vascular (moss and lichen) biomass is a dominant component (>90% of the photosynthetic biomass) of the vegetation across the full extent of arctic tundra, and should continue to be recognized as crucial for Earth system modeling. This study is one of only a few that present data on tundra vegetation across the temperature extent of the biome, providing (a) key links to satellite-based vegetation indices, (b) baseline field-data for ecosystem change studies, and (c) context for the ongoing changes in arctic tundra vegetation.

Published
2020
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