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173 results on '"Keuper, Frida"'

1. Trade‐offs and synergies of soil carbon sequestration: Addressing knowledge gaps related to soil management strategies

Author

Maenhout, Peter, primary, Di Bene, Claudia, additional, Cayuela, Maria Luz, additional, Diaz‐Pines, Eugenio, additional, Govednik, Anton, additional, Keuper, Frida, additional, Mavsar, Sara, additional, Mihelic, Rok, additional, O'Toole, Adam, additional, Schwarzmann, Ana, additional, Suhadolc, Marjetka, additional, Syp, Alina, additional, and Valkama, Elena, additional

Published
2024
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9. Arctic rooting depth distribution influences modelled carbon emissions but cannot be inferred from aboveground vegetation type

Author

Blume-Werry, Gesche, Dorrepaal, Ellen, Keuper, Frida, Kummu, Matti, Wild, Birgit, Weedon, James T. T., Blume-Werry, Gesche, Dorrepaal, Ellen, Keuper, Frida, Kummu, Matti, Wild, Birgit, and Weedon, James T. T.

Abstract

The distribution of roots throughout the soil drives depth-dependent plant-soil interactions and ecosystem processes, particularly in arctic tundra where plant biomass, is predominantly belowground. Vegetation is usually classified from aboveground, but it is unclear whether such classifications are suitable to estimate belowground attributes and their consequences, such as rooting depth distribution and its influence on carbon cycling. center dot We performed a meta-analysis of 55 published arctic rooting depth profiles, testing for differences both between distributions based on aboveground vegetation types (Graminoid, Wetland, Erect-shrub, and Prostrate-shrub tundra) and between ' Root Profile Types ' for which we defined three representative and contrasting clusters. We further analyzed potential impacts of these different rooting depth distributions on rhizosphere priming-induced carbon losses from tundra soils. center dot Rooting depth distribution hardly differed between aboveground vegetation types but varied between Root Profile Types. Accordingly, modelled priming-induced carbon emissions were similar between aboveground vegetation types when they were applied to the entire tundra, but ranged from 7.2 to 17.6 Pg C cumulative emissions until 2100 between individual Root Profile Types. center dot Variations in rooting depth distribution are important for the circumpolar tundra carbonclimate feedback but can currently not be inferred adequately from aboveground vegetation type classifications.

Published
2023
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10. Circum-Arctic peat soils resist priming by plant-derived compounds

Author

Wild, Birgit, Monteux, Sylvain, Wendler, Bernd, Hugelius, Gustaf, Keuper, Frida, Wild, Birgit, Monteux, Sylvain, Wendler, Bernd, Hugelius, Gustaf, and Keuper, Frida

Abstract

Rapid Arctic warming increases permafrost thaw and CO2 production from soil organic matter decomposition, but also enhances CO2 uptake by plants. Conversely, plants can also stimulate soil organic matter decomposition near their roots, via rhizosphere priming. The recent PrimeSCale model suggests that this can accelerate Arctic soil carbon loss at a globally relevant rate, and points to large potential contributions from carbon-rich permafrost peatlands. At the same time, the high carbon content of peatlands might render them insusceptible to input of easily available organic compounds by plant roots, which is considered a key component of priming. We here investigated the sensitivity of permafrost peat soils to priming by plant compounds under aerobic conditions that resemble the dominant rooting zone, based on a 30-week laboratory incubation of peat soils from five circum-Arctic locations. No significant change in CO2 production from peat organic matter by organic carbon addition was observed, and an increase of 24% by organic nitrogen addition. Combining our data with a literature meta-analysis of priming studies showed similar, low priming sensitivity in organic layers of mineral soils, and significantly stronger priming in mineral horizons where organic carbon and nitrogen increased decomposition by 32% and 62%, respectively. Low sensitivity of permafrost peat to input of organic compounds was also supported under anaerobic conditions, by incubation of one soil type. In a new PrimeSCale sensitivity analysis, we show that excluding peatlands would reduce estimates of priming-induced carbon loss from the circum-Arctic by up to 40% (up to 18 Pg) until 2100, depending on peat priming sensitivity. While our study suggests a limited effect of plant-released organic compounds on peat decomposition, it does not preclude an effect of vegetation on decomposition under natural conditions, through other mechanisms. The large range of possible priming-induced peat carbon lo

Published
2023
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11. The SOMMIT Project: SUstainable Management of soil Organic Matter to MItigate Trade-offs between C sequestration and nitrous oxide, methane and nitrate losses

Author

Diaz-Pines, Eugenio, primary, Keuper, Frida, additional, Bastida, Felipe, additional, Bregaglio, Simone, additional, Cayuela, Maria Luz, additional, Di Bene, Claudia, additional, Ferchaud, Fabien, additional, Ferrara, Rossana, additional, Fiore, Angela, additional, Léonard, Joel, additional, Maenhout, Peter, additional, Mihelič, Rok, additional, O´Toole, Adam, additional, Suhadolc, Marjetka, additional, Syp, Alina, additional, Testani, Elena, additional, Valkama, Elena, additional, and Lagomarsino, Alessandra, additional

Published
2023
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13. Can bryophyte groups increase functional resolution in tundra ecosystems?

Author

Lett, Signe, primary, Jónsdóttir, Ingibjörg S., additional, Becker-Scarpitta, Antoine, additional, Christiansen, Casper T., additional, During, Heinjo, additional, Ekelund, Flemming, additional, Henry, Gregory H.R., additional, Lang, Simone I., additional, Michelsen, Anders, additional, Rousk, Kathrin, additional, Alatalo, Juha M., additional, Betway, Katlyn R., additional, Rui, Sara B., additional, Callaghan, Terry, additional, Carbognani, Michele, additional, Cooper, Elisabeth J., additional, Cornelissen, J. Hans C., additional, Dorrepaal, Ellen, additional, Egelkraut, Dagmar, additional, Elumeeva, Tatiana G., additional, Haugum, Siri V., additional, Hollister, Robert D., additional, Jägerbrand, Annika K., additional, Keuper, Frida, additional, Klanderud, Kari, additional, Lévesque, Esther, additional, Liu, Xin, additional, May, Jeremy, additional, Michel, Pascale, additional, Mörsdorf, Martin, additional, Petraglia, Alessandro, additional, Rixen, Christian, additional, Robroek, Bjorn J.M., additional, Rzepczynska, Agnieszka M., additional, Soudzilovskaia, Nadejda A., additional, Tolvanen, Anne, additional, Vandvik, Vigdis, additional, Volkov, Igor, additional, Volkova, Irina, additional, and Zuijlen, Kristel van, additional

Published
2022
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15. Can bryophyte groups increase functional resolution in tundra ecosystems?

Author

Lett, Signe, Jónsdóttir, Ingibjörg Svala, Becker-scarpitta, Antoine, Christiansen, Casper T., During, Heinjo, Ekelund, Flemming, Henry, Greg H.r., Lang, Simone, Michelsen, Anders, Rousk, Kathrin, Alatalo, Juha, Betway, Katlyn Rose, Busca, Sara, Callaghan, Terry, Carbognani, Michele, Cooper, Elisabeth J., Cornelissen, Johannes H. C., Dorrepaal, Ellen, Egelkraut, Dagmar, Elumeeva, Tatiana G., Haugum, Siri V., Hollister, Robert D., Jägerbrand, Annika K., Keuper, Frida, Klanderud, Kari, Lévesque, Esther, Liu, Xin, May, Jeremy, Michel, Pascale, Mörsdorf, Martin A, Petraglia, Alessandro, Rixen, Christian, Robroek, Bjorn, Rzepczynska, Agnieszka M., Soudzilovskaia, Nadia, Tolvanen, Anne, Vandvik, Vigdis, Volkov, Igor, Volkova, Irina, Van Zuijlen, Kristel, Lett, Signe, Jónsdóttir, Ingibjörg Svala, Becker-scarpitta, Antoine, Christiansen, Casper T., During, Heinjo, Ekelund, Flemming, Henry, Greg H.r., Lang, Simone, Michelsen, Anders, Rousk, Kathrin, Alatalo, Juha, Betway, Katlyn Rose, Busca, Sara, Callaghan, Terry, Carbognani, Michele, Cooper, Elisabeth J., Cornelissen, Johannes H. C., Dorrepaal, Ellen, Egelkraut, Dagmar, Elumeeva, Tatiana G., Haugum, Siri V., Hollister, Robert D., Jägerbrand, Annika K., Keuper, Frida, Klanderud, Kari, Lévesque, Esther, Liu, Xin, May, Jeremy, Michel, Pascale, Mörsdorf, Martin A, Petraglia, Alessandro, Rixen, Christian, Robroek, Bjorn, Rzepczynska, Agnieszka M., Soudzilovskaia, Nadia, Tolvanen, Anne, Vandvik, Vigdis, Volkov, Igor, Volkova, Irina, and Van Zuijlen, Kristel

Abstract

The relative contribution of bryophytes to plant diversity, primary productivity, and ecosystem functioning increases towards colder climates. Bryophytes respond to environmental changes at the species level, but because bryophyte species are relatively difficult to identify, they are often lumped into one functional group. Consequently, bryophyte function remains poorly resolved. Here, we explore how higher resolution of bryophyte functional diversity can be encouraged and implemented in tundra ecological studies. We briefly review previous bryophyte functional classifications and the roles of bryophytes in tundra ecosystems and their susceptibility to environmental change. Based on shoot morphology and colony organization, we then propose twelve easily distinguishable bryophyte functional groups. To illustrate how bryophyte functional groups can help elucidate variation in bryophyte effects and responses, we compiled existing data on water holding capacity, a key bryophyte trait. Although plant functional groups can mask potentially high interspecific and intraspecific variability, we found better separation of bryophyte functional group means compared with previous grouping systems regarding water holding capacity. This suggests that our bryophyte functional groups truly represent variation in the functional roles of bryophytes in tundra ecosystems. Lastly, we provide recommendations to improve the monitoring of bryophyte community changes in tundra study sites.

Published
2022

16. Can bryophyte groups increase functional resolution in tundra ecosystems?

Author

Ecology and Biodiversity, Sub Ecology and Biodiversity, Lett, Signe, Jónsdóttir, Ingibjörg Svala, Becker-scarpitta, Antoine, Christiansen, Casper T., During, Heinjo, Ekelund, Flemming, Henry, Greg H.r., Lang, Simone, Michelsen, Anders, Rousk, Kathrin, Alatalo, Juha, Betway, Katlyn Rose, Busca, Sara, Callaghan, Terry, Carbognani, Michele, Cooper, Elisabeth J., Cornelissen, Johannes H. C., Dorrepaal, Ellen, Egelkraut, Dagmar, Elumeeva, Tatiana G., Haugum, Siri V., Hollister, Robert D., Jägerbrand, Annika K., Keuper, Frida, Klanderud, Kari, Lévesque, Esther, Liu, Xin, May, Jeremy, Michel, Pascale, Mörsdorf, Martin A, Petraglia, Alessandro, Rixen, Christian, Robroek, Bjorn, Rzepczynska, Agnieszka M., Soudzilovskaia, Nadia, Tolvanen, Anne, Vandvik, Vigdis, Volkov, Igor, Volkova, Irina, Van Zuijlen, Kristel, Ecology and Biodiversity, Sub Ecology and Biodiversity, Lett, Signe, Jónsdóttir, Ingibjörg Svala, Becker-scarpitta, Antoine, Christiansen, Casper T., During, Heinjo, Ekelund, Flemming, Henry, Greg H.r., Lang, Simone, Michelsen, Anders, Rousk, Kathrin, Alatalo, Juha, Betway, Katlyn Rose, Busca, Sara, Callaghan, Terry, Carbognani, Michele, Cooper, Elisabeth J., Cornelissen, Johannes H. C., Dorrepaal, Ellen, Egelkraut, Dagmar, Elumeeva, Tatiana G., Haugum, Siri V., Hollister, Robert D., Jägerbrand, Annika K., Keuper, Frida, Klanderud, Kari, Lévesque, Esther, Liu, Xin, May, Jeremy, Michel, Pascale, Mörsdorf, Martin A, Petraglia, Alessandro, Rixen, Christian, Robroek, Bjorn, Rzepczynska, Agnieszka M., Soudzilovskaia, Nadia, Tolvanen, Anne, Vandvik, Vigdis, Volkov, Igor, Volkova, Irina, and Van Zuijlen, Kristel

Published
2022

19. Multi-Decadal Changes in Tundra Environments and Ecosystems: Synthesis of the International Polar Year-Back to the Future Project (IPY-BTF)

Author

Callaghan, Terry V., Tweedie, Craig E., Åkerman, Jonas, Andrews, Christopher, Bergstedt, Johan, Butler, Malcolm G., Christensen, Torben R., Cooley, Dorothy, Dahlberg, Ulrika, Danby, Ryan K., Daniëls, Fred J. A., de Molenaar, Johannes G., Dick, Jan, Mortensen, Christian Ebbe, Ebert-May, Diane, Emanuelsson, Urban, Eriksson, Håkan, Hedenås, Henrik, Henry, Greg. H. R., Hik, David S., Hobbie, John E., Jantze, Elin J., Jaspers, Cornelia, Johansson, Cecilia, Johansson, Margareta, Johnson, David R., Johnstone, Jill F., Jonasson, Christer, Kennedy, Catherine, Kenney, Alice J., Keuper, Frida, Koh, Saewan, Krebs, Charles J., Lantuit, Hugues, Lara, Mark J., Lin, David, Lougheed, Vanessa L., Madsen, Jesper, Matveyeva, Nadya, McEwen, Daniel C., Myers-Smith, Isla H., Narozhniy, Yuriy K., Olsson, Håkan, Pohjola, Veijo A., Price, Larry W., Rigét, Frank, Rundqvist, Sara, Sandström, Anneli, Tamstorf, Mikkel, Van Bogaert, Rik, Villarreal, Sandra, Webber, Patrick J., and Zemtsov, Valeriy A.

Published
2011
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21. Biogeochemical responses of plants, soils and microbes to permafrost degradation in a subarctic peatland

Author

Oriol Grau, Olga Margalef, Joosten Hans, Richter Andreas, Canarini Alberto, Dorrepaal Ellen, Keuper Frida, Sardans Jordi, Peñuelas Josep, and Janssens Ivan

Abstract

Permafrost peatlands are particularly sensitive to climate warming. The thawing of permafrost in these ecosystems accelerates the decomposition of old organic matter in deep soil layers and re-activates the cycling of carbon (C) and nutrients. Several studies showed that the thawing of permafrost in subarctic peatlands increases nitrogen (N) availability, ecosystem productivity as well as methane (CH4) and C dioxide (CO2) emissions. The mobilisation of other nutrients like phosphorus (P) or potassium (K) and the stoichiometric changes occurring in plants, soils and microbes in these fragile ecosystems are nevertheless poorly understood. In June 2018 we collected plant and soil samples across several permafrost thaw gradients in a palsa mire complex at Stordalen (Abisko, 68°N, Sweden). We selected three contrasting situations across the gradients: a) peat mounds with an intact permafrost core (‘palsa’ areas), b) semi-degraded palsas (‘transition’ area), and c) completely degraded palsas with no permafrost (‘collapsed’ area). For each situation we collected samples of the aboveground vegetation and soil samples at 5-10, 40-45, 70-75 and 95-100 cm (layers A-D), encompassing peat (A and B) and mineral soil layers (C and D). We determined total C, N, P and K, extractable organic C (EOC), total extractable N (TEN), extractable organic N (EON), ammonium (NH4+), nitrate (NO3-), extractable organic and inorganic P (EOP and EIP), microbial enzymatic activity, microbial C, N and P and pH in soil samples at each of the four depths across the gradient. We also determined total C, N, P and K in aboveground vegetation samples. The uppermost soil layer A showed the most statistically significant changes across the gradient of permafrost thaw, namely a 2-fold increase of total N and total P, 3- fold increase of EIP, 4-fold increase of EOP and 5-fold increase of NH4+, along with an increase of potential extracellular enzymatic activity. The fraction of total P immobilised by microbes was highest in the uppermost soil layer of palsas, where microbial P reached 33% of total P. In layer B, there were also several significant changes, such as a 4-fold increase of EOC and TEN and 12-fold increase of NH4+ in transition areas, and a 4-fold increase of EOP in collapsed areas. In addition, foliar chemistry changed significatively across the gradient of permafrost thaw, with a generalised increase of N, P and K, and a decrease of the CN and NP ratios. Along with these changes in foliar chemistry there was an increase of the stocks of N, P and K in biomass across the gradient. The biogeochemical and stoichiometric changes observed in plants, soil and microbes at different soil layers and across the gradient of permafrost thaw evidence that ongoing and future environmental changes will have a major impact on the functioning of these fragile ecosystems in the Subarctic.

Published
2022
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22. Trade-offs between soil carbon sequestration and greenhouse gas emissions, and nitrogen leaching losses: addressing knowledge gaps

Author

Maenhout, Peter, primary, Di Bene, Claudia, additional, Cayuela, Maria Luz, additional, Govednik, Anton, additional, Keuper, Frida, additional, Mavsar, Sara, additional, Mihelic, Rok, additional, O'Toole, Adam, additional, Schwarzmann, Ana, additional, Suhadolc, Marjetka, additional, Syp, Alina, additional, and Valkama, Elena, additional

Published
2022
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23. Can bryophyte groups increase functional resolution in tundra ecosystems?

Author

Lett, Signe, Jónsdóttir, Ingibjörg Svala, Becker-scarpitta, Antoine, Christiansen, Casper T., During, Heinjo, Ekelund, Flemming, Henry, Greg H.r., Lang, Simone, Michelsen, Anders, Rousk, Kathrin, Alatalo, Juha, Betway, Katlyn Rose, Busca, Sara, Callaghan, Terry, Carbognani, Michele, Cooper, Elisabeth J., Cornelissen, Johannes H. C., Dorrepaal, Ellen, Egelkraut, Dagmar, Elumeeva, Tatiana G., Haugum, Siri V., Hollister, Robert D., Jägerbrand, Annika K., Keuper, Frida, Klanderud, Kari, Lévesque, Esther, Liu, Xin, May, Jeremy, Michel, Pascale, Mörsdorf, Martin A, Petraglia, Alessandro, Rixen, Christian, Robroek, Bjorn, Rzepczynska, Agnieszka M., Soudzilovskaia, Nadia, Tolvanen, Anne, Vandvik, Vigdis, Volkov, Igor, Volkova, Irina, Van Zuijlen, Kristel, Ecology and Biodiversity, Sub Ecology and Biodiversity, Ecology and Biodiversity, Sub Ecology and Biodiversity, Plant Production Sciences, Department of Agricultural Sciences, and Systems Ecology

Subjects
010504 meteorology & atmospheric sciences, Arctic–Alpine, Earth and Planetary Sciences(all), 010501 environmental sciences, 01 natural sciences, mosses, Environmental Science(all), Ecosystem, functional traits, Primary productivity, 0105 earth and related environmental sciences, General Environmental Science, Plant diversity, Ekologi, Ecology, water holding capacity, Agricultural and Biological Sciences(all), Resolution (electron density), Aquatic Ecology, environmental change, 15. Life on land, 11831 Plant biology, Tundra, General Earth and Planetary Sciences, Environmental science, Bryophyte, SDG 6 - Clean Water and Sanitation, General Agricultural and Biological Sciences
Abstract

Funding Information: This study was supported by a grant to SL from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie, Grant No. 797446 and by the Independent Research Fund Denmark, Grant no. 0135-00140B. Funding from the Academy of Finland (grant 322266), National Science Foundation (1504224, 1836839, PLR-1504381 and PLR-1836898), Independent Research Fund Denmark (9040-00314B), Moscow State University, (project No 121032500089-1), Natural Sciences and Engineering Research Council of Canada, ArcticNet, Polar Continental Shelf Program, Northern Science Training Program, Polar Knowledge Canada, Royal Canadian Mounted Police, Tomsk State University competitiveness improvement program and the Russian Science Foundation (grant No 20-67-46018) are gratefully acknowledged. Matthias Ahrens provided valuable insights on the cushion growth form, and we are most thankful. We thank Gaius Shaver and two anonymous reviewers for providing valuable critique and input to earlier versions of this manuscript. Publisher Copyright: © the author(s) or their institution(s). The relative contribution of bryophytes to plant diversity, primary productivity, and ecosystem functioning increases towards colder climates. Bryophytes respond to environmental changes at the species level, but because bryophyte species are relatively difficult to identify, they are often lumped into one functional group. Consequently, bryophyte function remains poorly resolved. Here, we explore how higher resolution of bryophyte functional diversity can be encouraged and implemented in tundra ecological studies. We briefly review previous bryophyte functional classifications and the roles of bryophytes in tundra ecosystems and their susceptibility to environmental change. Based on shoot morphology and colony organization, we then propose twelve easily distinguishable bryophyte functional groups. To illustrate how bryophyte functional groups can help elucidate variation in bryophyte effects and responses, we compiled existing data on water holding capacity, a key bryophyte trait. Although plant functional groups can mask potentially high interspecific and intraspecific variability, we found better separation of bryophyte functional group means compared with previous grouping systems regarding water holding capacity. This suggests that our bryophyte functional groups truly represent variation in the functional roles of bryophytes in tundra ecosystems. Lastly, we provide recommendations to improve the monitoring of bryophyte community changes in tundra study sites.

Published
2021
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24. Meshes in mesocosms control solute and biota exchange in soils : A step towards disentangling (a)biotic impacts on the fate of thawing permafrost

Author

Väisänen, Maria, Krab, Eveline J, Monteux, Sylvain, Teuber, Laurenz M., Gavazov, Konstantin, Weedon, James T., Keuper, Frida, Dorrepaal, Ellen, Väisänen, Maria, Krab, Eveline J, Monteux, Sylvain, Teuber, Laurenz M., Gavazov, Konstantin, Weedon, James T., Keuper, Frida, and Dorrepaal, Ellen

Abstract

Environmental changes feedback to climate through their impact on soil functions such as carbon (C) and nutrient sequestration. Abiotic conditions and the interactions between above- and belowground biota drive soil responses to environmental change but these (a)biotic interactions are challenging to study. Nonetheless, better understanding of these interactions would improve predictions of future soil functioning and the soil-climate feedback and, in this context, permafrost soils are of particular interest due to their vast soil C-stores. We need new tools to isolate abiotic (microclimate, chemistry) and biotic (roots, fauna, microorganisms) components and to identify their respective roles in soil processes. We developed a new experimental setup, in which we mimic thermokarst (permafrost thaw-induced soil subsidence) by fitting thawed permafrost and vegetated active layer sods side by side into mesocosms deployed in a subarctic tundra over two growing seasons. In each mesocosm, the two sods were separated from each other by barriers with different mesh sizes to allow varying degrees of physical connection and, consequently, (a)biotic exchange between active layer and permafrost. We demonstrate that our mesh-approach succeeded in controlling 1) lateral exchange of solutes between the two soil types, 2) colonization of permafrost by microbes but not by soil fauna, and 3) ingrowth of roots into permafrost. In particular, experimental thermokarst induced a similar to 60% decline in permafrost nitrogen (N) content, a shift in soil bacteria and a rapid buildup of root biomass (+33.2 g roots m(-2) soil). This indicates that cascading plant-soil-microbe linkages are at the heart of biogeochemical cycling in thermokarst events. We propose that this novel setup can be used to explore the effects of (a)biotic ecosystem components on focal biogeochemical processes in permafrost soils and beyond.

Published
2020
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26. Les nouveaux systèmes de culture pour favoriser la synchronisation sol/plante

Author

Cros, Camille, Alvarez, Gaël, Keuper, Frida, Revaillot, Sandrine, Fontaine, Sébastien, Unité Mixte de Recherche sur l'Ecosystème Prairial - UMR (UREP), Institut National de la Recherche Agronomique (INRA)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS), Agroressources et Impacts environnementaux (AgroImpact), Institut National de la Recherche Agronomique (INRA), and Laboratoire Microorganismes : Génome et Environnement - UMR 6023 Laboratoire Microorganismes : Génome et Environnement - UMR 6023.

Subjects
synchronisation sol/plante, nouveau système de culture, Biodiversité et Ecologie, N minéral, fertilisation N, Biodiversity and Ecology, fertilisation azotée, plateforme expérimentale, azote minéral, biomasse microbienne, mésocosme, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, ComputingMilieux_MISCELLANEOUS
Abstract

National audience

Published
2018

29. Launching the PrimeScale model: including the rhizosphere priming effect in spatial and depth explicit carbon loss estimate

Author

Keuper, Frida, Wild, Birgit, Kummu, Matti, Beer, Christian, Blume-Werry, Gesche, Fontaine, Sébastien, Gavazov, Konstantin, Gentsch, Norman, Guggenberger, Georg, Hugelius, G., Jalava, Mika, Koven, C., Krab, Eveline J., Kuhry, P., Monteux, Sylvain, Richter, Andreas, Shahzad, Tanvir, Weedon, James T., Dorrepaal, Ellen, Agroressources et Impacts environnementaux (AgroImpact), Institut National de la Recherche Agronomique (INRA), Stockholm University, Aalto University, Universität Greifswald - University of Greifswald, Unité Mixte de Recherche sur l'Ecosystème Prairial - UMR (UREP), Institut National de la Recherche Agronomique (INRA)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS), Ecole Polytechnique Fédérale de Lausanne (EPFL), Leibniz University Hannover, Lawrence Berkeley National Laboratory [Berkeley] (LBNL), Umeå University, University of Vienna [Vienna], Government College University of Faisalabad (GCUF), VU University Amsterdam, British Ecological Society (BES). Londres, GBR., European Ecological Federation (EEF). DEU., Vrije universiteit = Free university of Amsterdam [Amsterdam] (VU), and ProdInra, Migration

Subjects
[SDE.BE] Environmental Sciences/Biodiversity and Ecology, [SDE.ES] Environmental Sciences/Environmental and Society, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, [SDE.ES]Environmental Sciences/Environmental and Society, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2017

30. Circumpolar assessment of rhizosphere priming shows limited increase in carbon loss estimates for permafrost soils but large regional variability

Author

Keuper, Frida, Wild, Birgit, Kummu, Matti, Beer, Christian, Blume-Werry, Gesche, Fontaine, Sébastien, Gavazov, Konstantin, Gentsch, Norman, Guggenberger, Georg, Hugelius, G., Jalava, Mika, Koven, C., Krab, Eveline J., Kuhry, P., Monteux, Sylvain, Richter, Andreas, Shazhad, Tanvir, Weedon, James, Dorrepaal, Ellen, Agroressources et Impacts environnementaux (AgroImpact), Institut National de la Recherche Agronomique (INRA), Stockholm University, Aalto University, Universität Greifswald - University of Greifswald, Unité Mixte de Recherche sur l'Ecosystème Prairial - UMR (UREP), Institut National de la Recherche Agronomique (INRA)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS), Ecole Polytechnique Fédérale de Lausanne (EPFL), Leibniz University Hannover, Lawrence Berkeley National Laboratory [Berkeley] (LBNL), Umeå University, University of Vienna [Vienna], Government College University of Faisalabad (GCUF), Vrije universiteit = Free university of Amsterdam [Amsterdam] (VU), VU University Amsterdam, and ProdInra, Migration

Subjects
[SDE] Environmental Sciences, Carbon cycling, Soils/pedology, [SDV]Life Sciences [q-bio], biogeosciences, Permafrost, Biogeochemical cycles, processes, and modeling, cryosphere, eye diseases, [SDV] Life Sciences [q-bio], [SDE]Environmental Sciences, [SDV.BV]Life Sciences [q-bio]/Vegetal Biology, [SDV.BV] Life Sciences [q-bio]/Vegetal Biology, sense organs, global change
Abstract

International audience; Predictions of soil organic carbon (SOC) losses in the northern circumpolar permafrost area converge around 15% (± 3% standard error) of the initial C pool by 2100 under the RCP 8.5 warming scenario. Yet, none of these estimates consider plant-soil interactions such as the rhizosphere priming effect (RPE). While laboratory experiments have shown that the input of plant-derived compounds can stimulate SOC losses by up to 1200%, the magnitude of RPE in natural ecosystems is unknown and no methods for upscaling exist so far. We here present the first spatial and depth explicit RPE model that allows estimates of RPE on a large scale (PrimeSCale). We combine available spatial data (SOC, C/N, GPP, ALT and ecosystem type) and new ecological insights to assess the importance of the RPE at the circumpolar scale. We use a positive saturating relationship between the RPE and belowground C allocation and two ALT-dependent rooting-depth distribution functions (for tundra and boreal forest) to proportionally assign belowground C allocation and RPE to individual soil depth increments. The model permits to take into account reasonable limiting factors on additional SOC losses by RPE including interactions between spatial and/or depth variation in GPP, plant root density, SOC stocks and ALT. We estimate potential RPE-induced SOC losses at 9.7 Pg C (5 - 95% CI: 1.5 - 23.2 Pg C) by 2100 (RCP 8.5). This corresponds to an increase of the current permafrost SOC-loss estimate from 15% of the initial C pool to about 16%. If we apply an additional molar C/N threshold of 20 to account for microbial C limitation as a requirement for the RPE, SOC losses by RPE are further reduced to 6.5 Pg C (5 - 95% CI: 1.0 - 16.8 Pg C) by 2100 (RCP 8.5). Although our results show that current estimates of permafrost soil C losses are robust without taking into account the RPE, our model also highlights high-RPE risk in Siberian lowland areas and Alaska north of the Brooks Range. The small overall impact of the RPE is largely explained by the interaction between belowground plant C allocation and SOC depth distribution. Our findings thus highlight the importance of fine scale interactions between plant and soil properties for large scale carbon fluxes and we provide a first model that bridges this gap and permits the quantification of RPE across a large area.

Published
2017

31. Biodiversity and rhizosphere process in plant/soil synchronization

Author

Cros, Camille, Alvarez, Gaël, Keuper, Frida, Revaillot, Sandrine, Falcimagne, Robert, Fontaine, Sébastien, Unité Mixte de Recherche sur l'Ecosystème Prairial - UMR (UREP), and Institut National de la Recherche Agronomique (INRA)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)

Subjects
Biodiversity and Ecology, plateforme expérimentale, Biodiversité et Ecologie, [SDE.MCG]Environmental Sciences/Global Changes, mésocosme, flux de CO2, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Milieux et Changements globaux, écosystème prairial, Marquage 13C, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2017

32. Experimentally increased nutrient availability at the permafrost thaw front selectively enhances biomass production of deep-rooting subarctic peatland species

Author

Keuper, Frida, Dorrepaal, Ellen, van Bodegom, Peter M., van Logtestijn, Richard, Venhuizen, Gemma, van Hal, Jurgen, Aerts, Rien, Keuper, Frida, Dorrepaal, Ellen, van Bodegom, Peter M., van Logtestijn, Richard, Venhuizen, Gemma, van Hal, Jurgen, and Aerts, Rien

Abstract

Climate warming increases nitrogen (N) mineralization in superficial soil layers (the dominant rooting zone) of subarctic peatlands. Thawing and subsequent mineralization of permafrost increases plant-available N around the thaw-front. Because plant production in these peatlands is N-limited, such changes may substantially affect net primary production and species composition. We aimed to identify the potential impact of increased N-availability due to permafrost thawing on subarctic peatland plant production and species performance, relative to the impact of increased N-availability in superficial organic layers. Therefore, we investigated whether plant roots are present at the thaw-front (45 cm depth) and whether N-uptake (N-15-tracer) at the thaw-front occurs during maximum thaw-depth, coinciding with the end of the growing season. Moreover, we performed a unique 3-year belowground fertilization experiment with fully factorial combinations of deep-(thaw-front) and shallow-fertilization (10 cm depth) and controls. We found that certain species are present with roots at the thaw-front (Rubus chamaemorus) and have the capacity (R. chamaemorus, Eriophorum vaginatum) for N-uptake from the thaw-front between autumn and spring when aboveground tissue is largely senescent. In response to 3-year shallow-belowground fertilization (S) both shallow-(Empetrum hermaphroditum) and deep-rooting species increased aboveground biomass and N-content, but only deep-rooting species responded positively to enhanced nutrient supply at the thaw-front (D). Moreover, the effects of shallow-fertilization and thaw-front fertilization on aboveground biomass production of the deep-rooting species were similar in magnitude (S: 71%; D: 111% increase compared to control) and additive (S + D: 181% increase). Our results show that plant-available N released from thawing permafrost can form a thus far overlooked additional N-source for deep-rooting subarctic plant species and increase their biomass

Published
2017
Full Text
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33. Measuring rhizosphere regulations of carbon and nitrogen cycles: an innovate design

Author

Cros, Camille, Keuper, Frida, Alvarez, Gaël, Revaillot, Sandrine, Falcimagne, Robert, Salcedo, Alexandre, Fontaine, Sébastien, UR 0874 Unité de recherche sur l'Ecosystème Prairial, Institut National de la Recherche Agronomique (INRA)-Unité de recherche sur l'Ecosystème Prairial (UREP)-Ecologie des Forêts, Prairies et milieux Aquatiques (EFPA), Institut National de la Recherche Agronomique (INRA), Agroressources et Impacts environnementaux (AgroImpact), Unité Mixte de Recherche sur l'Ecosystème Prairial - UMR (UREP), Institut National de la Recherche Agronomique (INRA)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS), and Unité d'Agronomie de Laon-Reims-Mons (AGRO-LRM)

Subjects
rhizosphere regulations, [SDV]Life Sciences [q-bio], nitrogen cycles, carbon cycles
Abstract

CT3 ; EnjS2-4 ; Département EA; Measuring rhizosphere regulations of carbon and nitrogen cycles: an innovate design. EcoSummit 2016. Ecological Sustainability: Engineering Change

Published
2016

34. Carbon and nitrogen dynamics after destruction of a 6-year-old perennial bioenergy crop

Author

Bonis, Marie-Laure, Ferchaud, Fabien, Keuper, Frida, Chlebowski, Florent, Mary, Bruno, UR 1158 AgroImpact Agroressources et Impacts environnementaux, Institut National de la Recherche Agronomique (INRA), Agroressources et Impacts environnementaux (AgroImpact), and ProdInra, Archive Ouverte

Subjects
[SDV] Life Sciences [q-bio], Carbon dynamic, [SDV]Life Sciences [q-bio], nitrogen dynamics, 6-year-old perennial bioenergy crop
Abstract

CT3 ; EnjS1-4 ; Département EA, SOERE; Carbon and nitrogen dynamics after destruction of a 6-year-old perennial bioenergy crop. EcoSummit 2016. Ecological Sustainability: Engineering Change

Published
2016

35. Biodiversity and rhizosphere process in plant/soil synchronization

Author

Cros, Camille, Alvarez, Gaël, Keuper, Frida, Revaillot, Sandrine, Fontaine, Sébastien, UR 0874 Unité de recherche sur l'Ecosystème Prairial, Institut National de la Recherche Agronomique (INRA)-Unité de recherche sur l'Ecosystème Prairial (UREP)-Ecologie des Forêts, Prairies et milieux Aquatiques (EFPA), and Institut National de la Recherche Agronomique (INRA)

Subjects
synchronisation sol/plante, plateforme expérimentale, [SDV]Life Sciences [q-bio], flux de co2, mésocosme, marquage 13c, ComputingMilieux_MISCELLANEOUS, flux de CO2, Marquage 13C
Abstract

International audience

Published
2016

38. Biomass offsets little or none of permafrost carbon release from soils, streams, and wildfire : an expert assessment

Author

Abbott, Benjamin W., Jones, Jeremy B., Schuur, Edward A. G., Chapin, F. Stuart, III, Bowden, William B., Bret-Harte, M. Syndonia, Epstein, Howard E., Flannigan, Michael D., Harms, Tamara K., Hollingsworth, Teresa N., Mack, Michelle C., McGuire, A. David, Natali, Susan M., Rocha, Adrian V., Tank, Suzanne E., Turetsky, Merritt R., Vonk, Jorien E., Wickland, Kimberly P., Aiken, George R., Alexander, Heather D., Amon, Rainer M. W., Benscoter, Brian W., Bergeron, Yves, Bishop, Kevin, Blarquez, Olivier, Bond-Lamberty, Ben, Breen, Amy L., Buffam, Ishi, Cai, Yihua, Carcaillet, Christopher, Carey, Sean K., Chen, Jing M., Chen, Han Y. H., Christensen, Torben R., Cooper, Lee W., Cornelissen, J. Hans C., de Groot, William J., DeLuca, Thomas H., Dorrepaal, Ellen, Fetcher, Ned, Finlay, Jacques C., Forbes, Bruce C., French, Nancy H. F., Gauthier, Sylvie, Girardin, Martin P., Goetz, Scott J., Goldammer, Johann G., Gough, Laura, Grogan, Paul, Guo, Laodong, Higuera, Philip E., Hinzman, Larry, Hu, Feng Sheng, Hugelius, Gustaf, Jafarov, Elchin E., Jandt, Randi, Johnstone, Jill F., Karlsson, Jan, Kasischke, Eric S., Kattner, Gerhard, Kelly, Ryan, Keuper, Frida, Kling, George W., Kortelainen, Pirkko, Kouki, Jari, Kuhry, Peter, Laudon, Hjalmar, Laurion, Isabelle, Macdonald, Robie W., Mann, Paul J., Martikainen, Pertti J., McClelland, James W., Molau, Ulf, Oberbauer, Steven F., Olefeldt, David, Pare, David, Parisien, Marc-Andre, Payette, Serge, Peng, Changhui, Pokrovsky, Oleg S., Rastetter, Edward B., Raymond, Peter A., Raynolds, Martha K., Rein, Guillermo, Reynolds, James F., Robards, Martin, Rogers, Brendan M., Schaedel, Christina, Schaefer, Kevin, Schmidt, Inger K., Shvidenko, Anatoly, Sky, Jasper, Spencer, Robert G. M., Starr, Gregory, Striegl, Robert G., Teisserenc, Roman, Tranvik, Lars J., Virtanen, Tarmo, Welker, Jeffrey M., Zimov, Sergei, Abbott, Benjamin W., Jones, Jeremy B., Schuur, Edward A. G., Chapin, F. Stuart, III, Bowden, William B., Bret-Harte, M. Syndonia, Epstein, Howard E., Flannigan, Michael D., Harms, Tamara K., Hollingsworth, Teresa N., Mack, Michelle C., McGuire, A. David, Natali, Susan M., Rocha, Adrian V., Tank, Suzanne E., Turetsky, Merritt R., Vonk, Jorien E., Wickland, Kimberly P., Aiken, George R., Alexander, Heather D., Amon, Rainer M. W., Benscoter, Brian W., Bergeron, Yves, Bishop, Kevin, Blarquez, Olivier, Bond-Lamberty, Ben, Breen, Amy L., Buffam, Ishi, Cai, Yihua, Carcaillet, Christopher, Carey, Sean K., Chen, Jing M., Chen, Han Y. H., Christensen, Torben R., Cooper, Lee W., Cornelissen, J. Hans C., de Groot, William J., DeLuca, Thomas H., Dorrepaal, Ellen, Fetcher, Ned, Finlay, Jacques C., Forbes, Bruce C., French, Nancy H. F., Gauthier, Sylvie, Girardin, Martin P., Goetz, Scott J., Goldammer, Johann G., Gough, Laura, Grogan, Paul, Guo, Laodong, Higuera, Philip E., Hinzman, Larry, Hu, Feng Sheng, Hugelius, Gustaf, Jafarov, Elchin E., Jandt, Randi, Johnstone, Jill F., Karlsson, Jan, Kasischke, Eric S., Kattner, Gerhard, Kelly, Ryan, Keuper, Frida, Kling, George W., Kortelainen, Pirkko, Kouki, Jari, Kuhry, Peter, Laudon, Hjalmar, Laurion, Isabelle, Macdonald, Robie W., Mann, Paul J., Martikainen, Pertti J., McClelland, James W., Molau, Ulf, Oberbauer, Steven F., Olefeldt, David, Pare, David, Parisien, Marc-Andre, Payette, Serge, Peng, Changhui, Pokrovsky, Oleg S., Rastetter, Edward B., Raymond, Peter A., Raynolds, Martha K., Rein, Guillermo, Reynolds, James F., Robards, Martin, Rogers, Brendan M., Schaedel, Christina, Schaefer, Kevin, Schmidt, Inger K., Shvidenko, Anatoly, Sky, Jasper, Spencer, Robert G. M., Starr, Gregory, Striegl, Robert G., Teisserenc, Roman, Tranvik, Lars J., Virtanen, Tarmo, Welker, Jeffrey M., and Zimov, Sergei

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.

Published
2016
Full Text
View/download PDF

39. Biomass offsets little or none of permafrost carbon release from soils, streams, and wildfire

Author

University of Helsinki, Department of Environmental Sciences, Abbott, Benjamin W., Jones, Jeremy B., Schuur, Edward A. G., Chapin, F. Stuart, Bowden, William B., Bret-Harte, M. Syndonia, Epstein, Howard E., Flannigan, Michael D., Harms, Tamara K., Hollingsworth, Teresa N., Mack, Michelle C., McGuire, A. David, Natali, Susan M., Rocha, Adrian V., Tank, Suzanne E., Turetsky, Merritt R., Vonk, Jorien E., Wickland, Kimberly P., Aiken, George R., Alexander, Heather D., Amon, Rainer M. W., Benscoter, Brian W., Bergeron, Yves, Bishop, Kevin, Blarquez, Olivier, Bond-Lamberty, Ben, Breen, Amy L., Buffam, Ishi, Cai, Yihua, Carcaillet, Christopher, Carey, Sean K., Chen, Jing M., Chen, Han Y. H., Christensen, Torben R., Cooper, Lee W., Cornelissen, J. Hans C., de Groot, William J., DeLuca, Thomas H., Dorrepaal, Ellen, Fetcher, Ned, Finlay, Jacques C., Forbes, Bruce C., French, Nancy H. F., Gauthier, Sylvie, Girardin, Martin P., Goetz, Scott J., Goldammer, Johann G., Gough, Laura, Grogan, Paul, Guo, Laodong, Higuera, Philip E., Hinzman, Larry, Hu, Feng Sheng, Hugelius, Gustaf, Jafarov, Elchin E., Jandt, Randi, Johnstone, Jill F., Karlsson, Jan, Kasischke, Eric S., Kattner, Gerhard, Kelly, Ryan, Keuper, Frida, Kling, George W., Kortelainen, Pirkko, Kouki, Jari, Kuhry, Peter, Laudon, Hjalmar, Laurion, Isabelle, Macdonald, Robie W., Mann, Paul J., Martikainen, Pertti J., McClelland, James W., Molau, Ulf, Oberbauer, Steven F., Olefeldt, David, Pare, David, Parisien, Marc-Andre, Payette, Serge, Peng, Changhui, Pokrovsky, Oleg S., Rastetter, Edward B., Raymond, Peter A., Raynolds, Martha K., Rein, Guillermo, Reynolds, James F., Robards, Martin, Rogers, Brendan M., Schaedel, Christina, Schaefer, Kevin, Schmidt, Inger K., Shvidenko, Anatoly, Sky, Jasper, Spencer, Robert G. M., Starr, Gregory, Striegl, Robert G., Teisserenc, Roman, Tranvik, Lars J., Virtanen, Tarmo, Welker, Jeffrey M., Zimov, Sergei, University of Helsinki, Department of Environmental Sciences, Abbott, Benjamin W., Jones, Jeremy B., Schuur, Edward A. G., Chapin, F. Stuart, Bowden, William B., Bret-Harte, M. Syndonia, Epstein, Howard E., Flannigan, Michael D., Harms, Tamara K., Hollingsworth, Teresa N., Mack, Michelle C., McGuire, A. David, Natali, Susan M., Rocha, Adrian V., Tank, Suzanne E., Turetsky, Merritt R., Vonk, Jorien E., Wickland, Kimberly P., Aiken, George R., Alexander, Heather D., Amon, Rainer M. W., Benscoter, Brian W., Bergeron, Yves, Bishop, Kevin, Blarquez, Olivier, Bond-Lamberty, Ben, Breen, Amy L., Buffam, Ishi, Cai, Yihua, Carcaillet, Christopher, Carey, Sean K., Chen, Jing M., Chen, Han Y. H., Christensen, Torben R., Cooper, Lee W., Cornelissen, J. Hans C., de Groot, William J., DeLuca, Thomas H., Dorrepaal, Ellen, Fetcher, Ned, Finlay, Jacques C., Forbes, Bruce C., French, Nancy H. F., Gauthier, Sylvie, Girardin, Martin P., Goetz, Scott J., Goldammer, Johann G., Gough, Laura, Grogan, Paul, Guo, Laodong, Higuera, Philip E., Hinzman, Larry, Hu, Feng Sheng, Hugelius, Gustaf, Jafarov, Elchin E., Jandt, Randi, Johnstone, Jill F., Karlsson, Jan, Kasischke, Eric S., Kattner, Gerhard, Kelly, Ryan, Keuper, Frida, Kling, George W., Kortelainen, Pirkko, Kouki, Jari, Kuhry, Peter, Laudon, Hjalmar, Laurion, Isabelle, Macdonald, Robie W., Mann, Paul J., Martikainen, Pertti J., McClelland, James W., Molau, Ulf, Oberbauer, Steven F., Olefeldt, David, Pare, David, Parisien, Marc-Andre, Payette, Serge, Peng, Changhui, Pokrovsky, Oleg S., Rastetter, Edward B., Raymond, Peter A., Raynolds, Martha K., Rein, Guillermo, Reynolds, James F., Robards, Martin, Rogers, Brendan M., Schaedel, Christina, Schaefer, Kevin, Schmidt, Inger K., Shvidenko, Anatoly, Sky, Jasper, Spencer, Robert G. M., Starr, Gregory, Striegl, Robert G., Teisserenc, Roman, Tranvik, Lars J., Virtanen, Tarmo, Welker, Jeffrey M., and Zimov, Sergei

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.

Published
2016

40. Biomass offsets little or none of permafrost carbon release from soils, streams, and wildfire: an expert assessment

Author

Abbott, Benjamin W, Jones, Jeremy B, Schuur, Edward A G, Chapin III, F Stuart, Bowden, William B, Bret-Harte, M Syndonia, Epstein, Howard E, Flannigan, Michael D, Harms, Tamara K, Hollingsworth, Teresa N, Mack, Michelle C, McGuire, A David, Natali, Susan M, Rocha, Adrian V, Tank, Suzanne E, Turetsky, Merritt R, Vonk, Jorien E, Wickland, Kimberly P, Aiken, George R, Alexander, Heather D, Amon, Rainer M W, Benscoter, Brian W, Bergeron, Yves, Bishop, Kevin, Blarquez, Olivier, Bond-Lamberty, Ben, Breen, Amy L, Buffam, Ishi, Cai, Yihua, Carcaillet, Christopher, Carey, Sean K, Chen, Jing M, Chen, Han Y H, Christensen, Torben R, Cooper, Lee W, Cornelissen, J Hans C, de Groot, William J, DeLuca, Thomas H, Dorrepaal, Ellen, Fetcher, Ned, Finlay, Jacques C, Forbes, Bruce C, French, Nancy H F, Gauthier, Sylvie, Girardin, Martin P, Goetz, Scott J, Goldammer, Johann G, Gough, Laura, Grogan, Paul, Guo, Laodong, Higuera, Philip E, Hinzman, Larry, Hu, Feng Sheng, Hugelius, Gustaf, Jafarov, Elchin E, Jandt, Randi, Johnstone, Jill F, Karlsson, Jan, Kasischke, Eric S, Kattner, Gerhard, Kelly, Ryan, Keuper, Frida, Kling, George W, Kortelainen, Pirkko, Kouki, Jari, Kuhry, Peter, Laudon, Hjalmar, Laurion, Isabelle, Macdonald, Robie W, Mann, Paul J, Martikainen, Pertti J, McClelland, James W, Molau, Ulf, Oberbauer, Steven F, Olefeldt, David, Paré, David, Parisien, Marc-André, Payette, Serge, Peng, Changhui, Pokrovsky, Oleg S, Rastetter, Edward B, Raymond, Peter A, Raynolds, Martha K, Rein, Guillermo, Reynolds, James F, Robards, Martin, Rogers, Brendan M, Schädel, Christina, Schaefer, Kevin, Schmidt, Inger K, Shvidenko, Anatoly, Sky, Jasper, Spencer, Robert G M, Starr, Gregory, Striegl, Robert G, Teisserenc, Roman, Tranvik, Lars J, Virtanen, Tarmo, Welker, Jeffrey M, Zimov, Sergei, Abbott, Benjamin W, Jones, Jeremy B, Schuur, Edward A G, Chapin III, F Stuart, Bowden, William B, Bret-Harte, M Syndonia, Epstein, Howard E, Flannigan, Michael D, Harms, Tamara K, Hollingsworth, Teresa N, Mack, Michelle C, McGuire, A David, Natali, Susan M, Rocha, Adrian V, Tank, Suzanne E, Turetsky, Merritt R, Vonk, Jorien E, Wickland, Kimberly P, Aiken, George R, Alexander, Heather D, Amon, Rainer M W, Benscoter, Brian W, Bergeron, Yves, Bishop, Kevin, Blarquez, Olivier, Bond-Lamberty, Ben, Breen, Amy L, Buffam, Ishi, Cai, Yihua, Carcaillet, Christopher, Carey, Sean K, Chen, Jing M, Chen, Han Y H, Christensen, Torben R, Cooper, Lee W, Cornelissen, J Hans C, de Groot, William J, DeLuca, Thomas H, Dorrepaal, Ellen, Fetcher, Ned, Finlay, Jacques C, Forbes, Bruce C, French, Nancy H F, Gauthier, Sylvie, Girardin, Martin P, Goetz, Scott J, Goldammer, Johann G, Gough, Laura, Grogan, Paul, Guo, Laodong, Higuera, Philip E, Hinzman, Larry, Hu, Feng Sheng, Hugelius, Gustaf, Jafarov, Elchin E, Jandt, Randi, Johnstone, Jill F, Karlsson, Jan, Kasischke, Eric S, Kattner, Gerhard, Kelly, Ryan, Keuper, Frida, Kling, George W, Kortelainen, Pirkko, Kouki, Jari, Kuhry, Peter, Laudon, Hjalmar, Laurion, Isabelle, Macdonald, Robie W, Mann, Paul J, Martikainen, Pertti J, McClelland, James W, Molau, Ulf, Oberbauer, Steven F, Olefeldt, David, Paré, David, Parisien, Marc-André, Payette, Serge, Peng, Changhui, Pokrovsky, Oleg S, Rastetter, Edward B, Raymond, Peter A, Raynolds, Martha K, Rein, Guillermo, Reynolds, James F, Robards, Martin, Rogers, Brendan M, Schädel, Christina, Schaefer, Kevin, Schmidt, Inger K, Shvidenko, Anatoly, Sky, Jasper, Spencer, Robert G M, Starr, Gregory, Striegl, Robert G, Teisserenc, Roman, Tranvik, Lars J, Virtanen, Tarmo, Welker, Jeffrey M, and Zimov, Sergei

Published
2016

41. Biomass offsets little or none of permafrost carbon release from soils, streams, and wildfire:an expert assessment

Author

Abbott, Benjamin W., Jones, Jeremy B., Schuur, Edward A. G., Chapin, F. Stuart, III, Bowden, William B., Bret-Harte, M. Syndonia, Epstein, Howard E., Flannigan, Michael D., Harms, Tamara K., Hollingsworth, Teresa N., Mack, Michelle C., McGuire, A. David, Natali, Susan M., Rocha, Adrian V., Tank, Suzanne E., Turetsky, Merritt R., Vonk, Jorien E., Wickland, Kimberly P., Aiken, George R., Alexander, Heather D., Amon, Rainer M. W., Benscoter, Brian W., Bergeron, Yves, Bishop, Kevin, Blarquez, Olivier, Bond-Lamberty, Ben, Breen, Amy L., Buffam, Ishi, Cai, Yihua, Carcaillet, Christopher, Carey, Sean K., Chen, Jing M., Chen, Han Y. H., Christensen, Torben R., Cooper, Lee W., Cornelissen, J. Hans C., de Groot, William J., DeLuca, Thomas H., Dorrepaal, Ellen, Fetcher, Ned, Finlay, Jacques C., Forbes, Bruce C., French, Nancy H. F., Gauthier, Sylvie, Girardin, Martin P., Goetz, Scott J., Goldammer, Johann G., Gough, Laura, Grogan, Paul, Guo, Laodong, Higuera, Philip E., Hinzman, Larry, Hu, Feng Sheng, Hugelius, Gustaf, Jafarov, Elchin E., Jandt, Randi, Johnstone, Jill F., Karlsson, Jan, Kasischke, Eric S., Kattner, Gerhard, Kelly, Ryan, Keuper, Frida, Kling, George W., Kortelainen, Pirkko, Kouki, Jari, Kuhry, Peter, Laudon, Hjalmar, Laurion, Isabelle, Macdonald, Robie W., Mann, Paul J., Martikainen, Pertti J., McClelland, James W., Molau, Ulf, Oberbauer, Steven F., Olefeldt, David, Pare, David, Parisien, Marc-Andre, Payette, Serge, Peng, Changhui, Pokrovsky, Oleg S., Rastetter, Edward B., Raymond, Peter A., Raynolds, Martha K., Rein, Guillermo, Reynolds, James F., Robards, Martin, Rogers, Brendan M., Schaedel, Christina, Schaefer, Kevin, Schmidt, Inger Kappel, Shvidenko, Anatoly, Sky, Jasper, Spencer, Robert G. M., Starr, Gregory, Striegl, Robert G., Teisserenc, Roman, Tranvik, Lars J., Virtanen, Tarmo, Welker, Jeffrey M., Zimov, Sergei, Abbott, Benjamin W., Jones, Jeremy B., Schuur, Edward A. G., Chapin, F. Stuart, III, Bowden, William B., Bret-Harte, M. Syndonia, Epstein, Howard E., Flannigan, Michael D., Harms, Tamara K., Hollingsworth, Teresa N., Mack, Michelle C., McGuire, A. David, Natali, Susan M., Rocha, Adrian V., Tank, Suzanne E., Turetsky, Merritt R., Vonk, Jorien E., Wickland, Kimberly P., Aiken, George R., Alexander, Heather D., Amon, Rainer M. W., Benscoter, Brian W., Bergeron, Yves, Bishop, Kevin, Blarquez, Olivier, Bond-Lamberty, Ben, Breen, Amy L., Buffam, Ishi, Cai, Yihua, Carcaillet, Christopher, Carey, Sean K., Chen, Jing M., Chen, Han Y. H., Christensen, Torben R., Cooper, Lee W., Cornelissen, J. Hans C., de Groot, William J., DeLuca, Thomas H., Dorrepaal, Ellen, Fetcher, Ned, Finlay, Jacques C., Forbes, Bruce C., French, Nancy H. F., Gauthier, Sylvie, Girardin, Martin P., Goetz, Scott J., Goldammer, Johann G., Gough, Laura, Grogan, Paul, Guo, Laodong, Higuera, Philip E., Hinzman, Larry, Hu, Feng Sheng, Hugelius, Gustaf, Jafarov, Elchin E., Jandt, Randi, Johnstone, Jill F., Karlsson, Jan, Kasischke, Eric S., Kattner, Gerhard, Kelly, Ryan, Keuper, Frida, Kling, George W., Kortelainen, Pirkko, Kouki, Jari, Kuhry, Peter, Laudon, Hjalmar, Laurion, Isabelle, Macdonald, Robie W., Mann, Paul J., Martikainen, Pertti J., McClelland, James W., Molau, Ulf, Oberbauer, Steven F., Olefeldt, David, Pare, David, Parisien, Marc-Andre, Payette, Serge, Peng, Changhui, Pokrovsky, Oleg S., Rastetter, Edward B., Raymond, Peter A., Raynolds, Martha K., Rein, Guillermo, Reynolds, James F., Robards, Martin, Rogers, Brendan M., Schaedel, Christina, Schaefer, Kevin, Schmidt, Inger Kappel, Shvidenko, Anatoly, Sky, Jasper, Spencer, Robert G. M., Starr, Gregory, Striegl, Robert G., Teisserenc, Roman, Tranvik, Lars J., Virtanen, Tarmo, Welker, Jeffrey M., and Zimov, Sergei

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.

Published
2016

42. A Race for Space? How Sphagnum fuscum stabilizes vegetation composition during long-term climate manipulations

Author

Keuper, Frida, Dorrepaal, Ellen, Van Bodegom, Peter M, Aerts, Rien, Van Logtestijn, Richard, Callaghan, Terry V, Cornelissen, Johannes HC, Department of Systems Ecology, University of Amsterdam [Amsterdam] (UvA), Climate Impacts Research Centre (CIRC), Umeå University, Dept of Systems Ecology, Department of Animal and Plant Sciences, Sheffield Centre for Arctic Ecology, University of Sheffield, and Abisko Naturvetenskapliga Station, Royal Swedish Academy of Sciences

Subjects
Life Sciences
Abstract

International audience; Strong climate warming is predicted at higher latitudes this century, with potentially major consequences for productivity and carbon sequestration. Although northern peatlands contain one-third of the world's soil organic carbon, little is known about the long-term responses to experimental climate manipulations of vascular plant communities in these Sphagnum-dominated ecosystems. We aimed to see how long-term experimental climate change in and outside the growing season affects total vascular plant abundance and species composition when the community is dominated by mosses. During 8 years, we investigated how the vascular plant community of a Sphagnum fuscum-dominated subarctic peat bog responded to six experimental climate scenarios, including factorial combinations of summer as well as spring warming and a thicker snow cover. Vascular plant species composition in our peat bog was more stable than is typically observed in (sub)arctic experiments: neither changes in total vascular plant abundance, nor in individual species abundances, Shannon's diversity or evenness were found in response to the climate manipulations. For three key species (Empetrum hermaphroditum, Betula nana and S. fuscum) we also measured whether the treatments had a sustained effect on plant length growth responses and how these responses interacted. Contrasting with the stability at the community level, both key shrubs and the peatmoss showed sustained positive growth responses at the plant level to the climate treatments. However, a higher percentage of overgrown E. hermaphroditum shoots and a lack of change in B. nana net shrub height indicated encroachment by S. fuscum, resulting in long-term stability of the vascular community composition: in a warmer world, vascular species of subarctic peat bogs appear to just keep pace with growing Sphagnum in their race for space. Our findings contribute to general ecological theory by demonstrating that community resistance to environmental changes does not necessarily mean inertia in vegetation response.

Published
2011
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43. Northern peatland Collembola communities unaffected by three summers of simulated extreme precipitation

Author

Krab, Eveline J., Aerts, Rien, Berg, Matty P., van Hal, Jurgen, Keuper, Frida, Krab, Eveline J., Aerts, Rien, Berg, Matty P., van Hal, Jurgen, and Keuper, Frida

Abstract

Extreme climate events are observed and predicted to increase in frequency and duration in high-latitudeecosystems as a result of global climate change. This includes extreme precipitation events, which maydirectly impact on belowground food webs and ecosystem functioning by their physical impacts and byaltering local soil moisture conditions. We assessed responses of the Collembola community in a northern Sphagnum fuscum-dominatedombrotrophic peatland to three years of experimentally increased occurrence of extreme precipitationevents. Annual summer precipitation was doubled (an increase of 200 mm) by 16 simulated extremerain events within the three months growing season, where on each occasion 12.5 mm of rain was addedwithin a few minutes. Despite this high frequency and intensity of the rain events, no shifts in Collemboladensity, relative species abundances and community weighted means of three relevant traits (moisturepreference, vertical distribution and body size) were observed. This strongly suggests that the peatlandCollembola community is unaffected by the physical impacts of extreme precipitation and the short-termvariability in moisture conditions. The lack of response is most likely reinforced by the fact that extremeprecipitation events do not seem to alter longer-term soil moisture conditions in the peat layers inhabitedby soil fauna. This study adds evidence to the observation that the biotic components of northern ombrotrophicpeatlands are hardly responsive to an increase in extreme summer precipitation events. Given the importance of these ecosystems for the global C balance, these findings significantly contribute to the currentknowledge of the ecological impact of future climate scenarios. (C) 2014 Elsevier B.V. All rights reserved.

Published
2014
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45. Global assessment of experimental climate warming on tundra vegetation : heterogeneity over space and time

Author

Elmendorf, Sarah C., Henry, Gregory H. R., Hollister, Robert D., Alatalo, Juha, Bjork, Robert G., Bjorkman, Anne D., Callaghan, Terry V., Collier, Laura Siegwart, Cooper, Elisabeth J., Cornelissen, Johannes H. C., Day, Thomas A., Fosaa, Anna Maria, Gould, William A., Gretarsdottir, Jarngerdur, Harte, John, Hermanutz, Luise, Hik, David S., Hofgaard, Annika, Jarrad, Frith, Jonsdottir, Ingibjorg Svala, Keuper, Frida, Klanderud, Kari, Klein, Julia A., Koh, Saewan, Kudo, Gaku, Lang, Simone I., Loewen, Val, May, Jeremy L., Mercado, Joel, Michelsen, Anders, Molau, Ulf, Myers-Smith, Isla H., Oberbauer, Steven F., Pieper, Sara, Post, Eric, Rixen, Christian, Robinson, Clare H., Schmidt, Niels Martin, Shaver, Gaius R., Stenstrom, Anna, Tolvanen, Anne, Totland, Orjan, Troxler, Tiffany, Wahren, Carl-Henrik, Walker, Marilyn D., Webber, Patrick J., Welker, Jeffery M., Wookey, Philip A., Elmendorf, Sarah C., Henry, Gregory H. R., Hollister, Robert D., Alatalo, Juha, Bjork, Robert G., Bjorkman, Anne D., Callaghan, Terry V., Collier, Laura Siegwart, Cooper, Elisabeth J., Cornelissen, Johannes H. C., Day, Thomas A., Fosaa, Anna Maria, Gould, William A., Gretarsdottir, Jarngerdur, Harte, John, Hermanutz, Luise, Hik, David S., Hofgaard, Annika, Jarrad, Frith, Jonsdottir, Ingibjorg Svala, Keuper, Frida, Klanderud, Kari, Klein, Julia A., Koh, Saewan, Kudo, Gaku, Lang, Simone I., Loewen, Val, May, Jeremy L., Mercado, Joel, Michelsen, Anders, Molau, Ulf, Myers-Smith, Isla H., Oberbauer, Steven F., Pieper, Sara, Post, Eric, Rixen, Christian, Robinson, Clare H., Schmidt, Niels Martin, Shaver, Gaius R., Stenstrom, Anna, Tolvanen, Anne, Totland, Orjan, Troxler, Tiffany, Wahren, Carl-Henrik, Walker, Marilyn D., Webber, Patrick J., Welker, Jeffery M., and Wookey, Philip A.

Abstract

Understanding the sensitivity of tundra vegetation to climate warming is critical to forecasting future biodiversity and vegetation feedbacks to climate. In situ warming experiments accelerate climate change on a small scale to forecast responses of local plant communities. Limitations of this approach include the apparent site-specificity of results and uncertainty about the power of short-term studies to anticipate longer term change. We address these issues with a synthesis of 61 experimental warming studies, of up to 20 years duration, in tundra sites worldwide. The response of plant groups to warming often differed with ambient summer temperature, soil moisture and experimental duration. Shrubs increased with warming only where ambient temperature was high, whereas graminoids increased primarily in the coldest study sites. Linear increases in effect size over time were frequently observed. There was little indication of saturating or accelerating effects, as would be predicted if negative or positive vegetation feedbacks were common. These results indicate that tundra vegetation exhibits strong regional variation in response to warming, and that in vulnerable regions, cumulative effects of long-term warming on tundra vegetation and associated ecosystem consequences have the potential to be much greater than we have observed to date., The following authors were added to this article (see correction below):Alatalo, JuhaWalker, MarilynCorrection in: Ecology Letters, Vol. 17, Issue 2, page 260 (Feb 2014).DOI: 10.1111/ele.12218

Published
2012
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46. A frozen feast : thawing permafrost increases plant-available nitrogen in subarctic peatlands

Author

Keuper, Frida, van Bodegom, Peter M., Dorrepaal, Ellen, Weedon, James T., van Hal, Jurgen, van Logtestijn, Richard S. P., Aerts, Rien, Keuper, Frida, van Bodegom, Peter M., Dorrepaal, Ellen, Weedon, James T., van Hal, Jurgen, van Logtestijn, Richard S. P., and Aerts, Rien

Abstract

Many of the world's northern peatlands are underlain by rapidly thawing permafrost. Because plant production in these peatlands is often nitrogen (N)-limited, a release of N stored in permafrost may stimulate net primary production or change species composition if it is plant-available. In this study, we aimed to quantify plant-available N in thawing permafrost soils of subarctic peatlands. We compared plant-available N-pools and -fluxes in near-surface permafrost (010cm below the thawfront) to those taken from a current rooting zone layer (515cm depth) across five representative peatlands in subarctic Sweden. A range of complementary methods was used: extractions of inorganic and organic N, inorganic and organic N-release measurements at 0.5 and 11 degrees C (over 120days, relevant to different thaw-development scenarios) and a bioassay with Poa alpina test plants. All extraction methods, across all peatlands, consistently showed up to seven times more plant-available N in near-surface permafrost soil compared to the current rooting zone layer. These results were supported by the bioassay experiment, with an eightfold larger plant N-uptake from permafrost soil than from other N-sources such as current rooting zone soil or fresh litter substrates. Moreover, net mineralization rates were much higher in permafrost soils compared to soils from the current rooting zone layer (273mgNm-2 and 1348mgNm-2 per growing season for near-surface permafrost at 0.5 degrees C and 11 degrees C respectively, compared to -30mgNm-2 for current rooting zone soil at 11 degrees C). Hence, our results demonstrate that near-surface permafrost soil of subarctic peatlands can release a biologically relevant amount of plant available nitrogen, both directly upon thawing as well as over the course of a growing season through continued microbial mineralization of organically bound N. Given the nitrogen-limited nature of northern peatlands, this release may have impacts on both plant productivity

Published
2012
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47. Global assessment of experimental climate warming on tundra vegetation: Heterogeneity over space and time

Author

Elmendorf, Sarah, Henry, Gregory, Hollister, Robert, Bjork, Robert, Bjorkman, Anne, Callaghan, Terry, Siegwart Collier, Laura, Cooper, Elisabeth, Cornelissen, Johannes, Day, Thomas, Fosaa, Anna Maria, Gould, William, Gretarsdottir, Jarngerour, Harte, John, Hermanutz, Luise, Hik, David, Hofgaard, Annika, Jarrad, Frith, Jonsdottir, Ingibjorg Svala, Keuper, Frida, Klanderud, Kari, Klein, Julia, Koh, Saewan, Kudo, Gaku, Lang, Simone, Loewen, Val, May, Jeremy, Mercado, Joel, Michelsen, Anders, Molau, Ulf, Myers-Smith, Isla, Oberbauer, Steven, Pieper, Sara, Post, Eric, Rixen, Christian, Robinson, Clare, Schmidt, Niels Martin, Shaver, Gaius, Stenstrom, Anna, Tolvanen, Anne, Totland, Orjan, Troxler, Tiffany, Wahren, Carl-Henrich, Webber, Patrick, Welker, Jeffery, Wookey, Philip, Elmendorf, Sarah, Henry, Gregory, Hollister, Robert, Bjork, Robert, Bjorkman, Anne, Callaghan, Terry, Siegwart Collier, Laura, Cooper, Elisabeth, Cornelissen, Johannes, Day, Thomas, Fosaa, Anna Maria, Gould, William, Gretarsdottir, Jarngerour, Harte, John, Hermanutz, Luise, Hik, David, Hofgaard, Annika, Jarrad, Frith, Jonsdottir, Ingibjorg Svala, Keuper, Frida, Klanderud, Kari, Klein, Julia, Koh, Saewan, Kudo, Gaku, Lang, Simone, Loewen, Val, May, Jeremy, Mercado, Joel, Michelsen, Anders, Molau, Ulf, Myers-Smith, Isla, Oberbauer, Steven, Pieper, Sara, Post, Eric, Rixen, Christian, Robinson, Clare, Schmidt, Niels Martin, Shaver, Gaius, Stenstrom, Anna, Tolvanen, Anne, Totland, Orjan, Troxler, Tiffany, Wahren, Carl-Henrich, Webber, Patrick, Welker, Jeffery, and Wookey, Philip

Abstract

Understanding the sensitivity of tundra vegetation to climate warming is critical to forecasting future biodiversity and vegetation feedbacks to climate. In situ warming experiments accelerate climate change on a small scale to forecast responses of local plant communities. Limitations of this approach include the apparent site-specificity of results and uncertainty about the power of short-term studies to anticipate longer term change. We address these issues with a synthesis of 61 experimental warming studies, of up to 20 years duration, in tundra sites worldwide. The response of plant groups to warming often differed with ambient summer temperature, soil moisture and experimental duration. Shrubs increased with warming only where ambient temperature was high, whereas graminoids increased primarily in the coldest study sites. Linear increases in effect size over time were frequently observed. There was little indication of saturating or accelerating effects, as would be predicted if negative or positive vegetation feedbacks were common. These results indicate that tundra vegetation exhibits strong regional variation in response to warming, and that in vulnerable regions, cumulative effects of long-term warming on tundra vegetation – and associated ecosystem consequences – have the potential to be much greater than we have observed to date.

Published
2012

48. Tundra in the rain:differential vegetation responses to three years of experimentally doubled summer precipitation in Siberian shrub and Swedish bog tundra

Author

Keuper, Frida, Parmentier, Frans-Jan, Blok, Daan, van Bodegom, Peter, Dorrepaal, Ellen, Van Hal, Jurgen R., van Logtestijn, Richard, Aerts, Rien, Keuper, Frida, Parmentier, Frans-Jan, Blok, Daan, van Bodegom, Peter, Dorrepaal, Ellen, Van Hal, Jurgen R., van Logtestijn, Richard, and Aerts, Rien

Abstract

Precipitation amounts and patterns at high latitude sites have been predicted to change as a result of global climatic changes. We addressed vegetation responses to three years of experimentally increased summer precipitation in two previously unaddressed tundra types: Betula nana-dominated shrub tundra (northeast Siberia) and a dry Sphagnum fuscum-dominated bog (northern Sweden). Positive responses to approximately doubled ambient precipitation (an increase of 200 mm year-1) were observed at the Siberian site, for B. nana (30 % larger length increments), Salix pulchra (leaf size and length increments) and Arctagrostis latifolia (leaf size and specific leaf area), but none were observed at the Swedish site. Total biomass production did not increase at either of the study sites. This study corroborates studies in other tundra vegetation types and shows that despite regional differences at the plant level, total tundra plant productivity is, at least at the short or medium term, largely irresponsive to experimentally increased summer precipitation.

Published
2012

49. Global assessment of experimental climate warming on tundra vegetation:heterogeneity over space and time

Author

Elmendorf, Sarah C., Henry, Gregory H.R., Hollister, Robert D., Björk, Robert G., Bjorkman, Anne D., Callaghan, Terry V., Collier, Laura Siegwart, Cooper, Elisabeth J., Cornelissen, Johannes H.C., Day, Thomas A., Fosaa, Anna Maria, Gould, William A., Gretarsdottir, Jarngerdur, Harte, John, Hermanutz, Luise, Hik, David S., Hofgaard, Annika, Jarrad, Frith, Jonsdottir, Ingibjorg Svala, Keuper, Frida, Klanderud, Kari, Klein, Julia A., Koh, Saewan, Kudo, Gaku, Lang, Simone I., Loewen, Val, May, Jeremy L., Mercado, Joel, Michelsen, Anders, Molau, Ulf, Myers-Smith, Isla H., Oberbauer, Steven F., Pieper, Sara, Post, Eric, Rixen, Christian, Robinson, Clare H., Schmidt, Niels Martin, Shaver, Gaius R., Stenstrom, Anna, Tolvanen, Anne, Totland, Orjan, Troxler, Tiffany, Wahren, Carl-Henrik, Webber, Patrick J., Welker, Jeffery M., Wookey, Philip A., Elmendorf, Sarah C., Henry, Gregory H.R., Hollister, Robert D., Björk, Robert G., Bjorkman, Anne D., Callaghan, Terry V., Collier, Laura Siegwart, Cooper, Elisabeth J., Cornelissen, Johannes H.C., Day, Thomas A., Fosaa, Anna Maria, Gould, William A., Gretarsdottir, Jarngerdur, Harte, John, Hermanutz, Luise, Hik, David S., Hofgaard, Annika, Jarrad, Frith, Jonsdottir, Ingibjorg Svala, Keuper, Frida, Klanderud, Kari, Klein, Julia A., Koh, Saewan, Kudo, Gaku, Lang, Simone I., Loewen, Val, May, Jeremy L., Mercado, Joel, Michelsen, Anders, Molau, Ulf, Myers-Smith, Isla H., Oberbauer, Steven F., Pieper, Sara, Post, Eric, Rixen, Christian, Robinson, Clare H., Schmidt, Niels Martin, Shaver, Gaius R., Stenstrom, Anna, Tolvanen, Anne, Totland, Orjan, Troxler, Tiffany, Wahren, Carl-Henrik, Webber, Patrick J., Welker, Jeffery M., and Wookey, Philip A.

Abstract

Understanding the sensitivity of tundra vegetation to climate warming is critical to forecasting future biodiversity and vegetation feedbacks to climate. In situ warming experiments accelerate climate change on a small scale to forecast responses of local plant communities. Limitations of this approach include the apparent site-specificity of results and uncertainty about the power of short-term studies to anticipate longer term change. We address these issues with a synthesis of 61 experimental warming studies, of up to 20 years duration, in tundra sites worldwide. The response of plant groups to warming often differed with ambient summer temperature, soil moisture and experimental duration. Shrubs increased with warming only where ambient temperature was high, whereas graminoids increased primarily in the coldest study sites. Linear increases in effect size over time were frequently observed. There was little indication of saturating or accelerating effects, as would be predicted if negative or positive vegetation feedbacks were common. These results indicate that tundra vegetation exhibits strong regional variation in response to warming, and that in vulnerable regions, cumulative effects of long-term warming on tundra vegetation and associated ecosystem consequences have the potential to be much greater than we have observed to date.

Published
2012

50. A race for space? : How Sphagnum fuscumstabilizes vegetation composition during long-termclimate manipulations

Author

Keuper, Frida, Dorrepaal, Ellen, Van Bodegom, Peter M., Aerts, Rien, Van Logtestijn, Richard S.P., Callaghan, Terry V., Cornelissen, Johannes H . C ., Keuper, Frida, Dorrepaal, Ellen, Van Bodegom, Peter M., Aerts, Rien, Van Logtestijn, Richard S.P., Callaghan, Terry V., and Cornelissen, Johannes H . C .

Abstract

Strong climate warming is predicted at higher latitudes this century, with potentially major consequences forproductivity and carbon sequestration. Although northern peatlands contain one-third of the world’s soil organiccarbon, little is known about the long-term responses to experimental climate change of vascular plant communities inthese Sphagnum-dominated ecosystems.We aimed to see how long-term experimental climate manipulations, relevantto different predicted future climate scenarios, affect total vascular plant abundance and species composition whenthe community is dominated by mosses. During 8 years, we investigated how the vascular plant community of aSphagnum fuscum-dominated subarctic peat bog responded to six experimental climate regimes, including factorialcombinations of summer as well as spring warming and a thicker snow cover. Vascular plant species composition inour peat bog was more stable than is typically observed in (sub)arctic experiments: neither changes in total vascularplant abundance, nor in individual species abundances, Shannon’s diversity or evenness were found in response tothe climate manipulations. For three key species (Empetrum hermaphroditum, Betula nana and S. fuscum) we alsomeasured whether the treatments had a sustained effect on plant length growth responses and how these responsesinteracted. Contrasting with the stability at the community level, both key shrubs and the peatmoss showed sustainedpositive growth responses at the plant level to the climate treatments. However, a higher percentage of mossencroachedE. hermaphroditum shoots and a lack of change in B. nana net shrub height indicated encroachment byS. fuscum, resulting in long-term stability of the vascular community composition: in a warmer world, vascular speciesof subarctic peat bogs appear to just keep pace with growing Sphagnum in their race for space. Our findings contributeto general ecological theory by demonstrating that community resistance to environmental

Published
2011
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