DIRECT AND INDIRECT EFFECTS OF CLIMATIC CHANGES ON VEGETATION PRODUCTIVITY AND SPECIES COMPOSITION OF PERMAFROST PEATLANDS

• Main Author: Keuper, Frida
• Other Authors: BioEcoAgro - Equipe 2 - Integrated functioning of the soil-plant system and exchanges between the ecosystem and the hydrosphere and the atmosphere, BioEcoAgro - UMR transfrontalière INRAe - UMRT1158, Université d'Artois (UA)-Université de Liège-Université de Picardie Jules Verne (UPJV)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-JUNIA (JUNIA), Université catholique de Lille (UCL)-Université catholique de Lille (UCL)-Université d'Artois (UA)-Université de Liège-Université de Picardie Jules Verne (UPJV)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-JUNIA (JUNIA), Université catholique de Lille (UCL)-Université catholique de Lille (UCL), Vrije Universiteit Amsterdam, M.A.P.A. Aerts, P.M. van Bodegom
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: HAL CCSD 2012
• Subjects: Plant-soil interactions; climate change; permafrost; peatlands; nitrogen; carbon; Experimental research; Interactions plante-sol; Azote; Pergelisol; Tourbieres; [SDE]Environmental Sciences; Abisko; Northern Sweden
• Online Access: https://hal.inrae.fr/tel-04553164; https://hal.inrae.fr/tel-04553164/document; https://hal.inrae.fr/tel-04553164/file/KEUPER2012_PhDthesis_final.pdf

International audience Strong climate warming and altered precipitation regimes are predicted to occur at higherlatitudes this century, with potentially major consequences for vegetation productivity andcarbon sequestration. Although northern permafrost peatlands contain one-third of the world’ssoil organic carbon, little is known about responses of their vascular plant communities toclimatic changes. Both direct effects, of warming and altered precipitation, as well as indirecteffects, through permafrost thawing and increased nutrient-availability, are expected. In thisthesis I aimed to investigate how short- to long-term experimental climate manipulations,relevant to different predicted future climate scenarios, affect vascular plant productivity andspecies composition in permafrost peatlands. Specifically, answers were sought to the followingresearch questions: (1) How do spring- and summer warming, and increased snow cover affectspecies-specific growth responses and species composition in northern permafrost peatlands;(2) How does increased summer precipitation affect species-specific growth responses andspecies composition in northern permafrost peatlands; and (3) Can permafrost thawing affectspecies-specific growth responses and species composition in northern permafrost peatlandsthrough a release of plant-available N? To answer these questions three experiments wereperformed, investigating vegetation responses to: (a) spring- and summer warming and a thickersnow cover (Chapter 2); (b) increased summer precipitation (Chapter 3); and (c) increasednutrient availability at the permafrost thaw front (Chapter 5). Moreover, the amount of plant-available nitrogen (N) that can be released from thawing permafrost into these peatlands in thenear-future was quantified (Chapter 4). All experiments were performed on Sphagnum fuscum-dominated permafrost peatlands the Abisko area, northern Sweden. The increased summerprecipitation experiment (Chapter 3) was complemented by a sister-experiment in the KytalykReserve in ...