TY - JOUR

T1 - Environmental drivers of Sphagnum growth in peatlands across the Holarctic region

AU - Bengtsson, Fia

AU - Rydin, Håkan

AU - Baltzer, Jennifer L.

AU - Bragazza, Luca

AU - Bu, Zhao Jun

AU - Caporn, Simon J.M.

AU - Dorrepaal, Ellen

AU - Flatberg, Kjell Ivar

AU - Galanina, Olga

AU - Gałka, Mariusz

AU - Ganeva, Anna

AU - Goia, Irina

AU - Goncharova, Nadezhda

AU - Hájek, Michal

AU - Haraguchi, Akira

AU - Harris, Lorna I.

AU - Humphreys, Elyn

AU - Jiroušek, Martin

AU - Kajukało, Katarzyna

AU - Karofeld, Edgar

AU - Koronatova, Natalia G.

AU - Kosykh, Natalia P.

AU - Laine, Anna M.

AU - Lamentowicz, Mariusz

AU - Lapshina, Elena

AU - Limpens, Juul

AU - Linkosalmi, Maiju

AU - Ma, Jin Ze

AU - Mauritz, Marguerite

AU - Mitchell, Edward A.D.

AU - Munir, Tariq M.

AU - Natali, Susan M.

AU - Natcheva, Rayna

AU - Payne, Richard J.

AU - Philippov, Dmitriy A.

AU - Rice, Steven K.

AU - Robinson, Sean

AU - Robroek, Bjorn J.M.

AU - Rochefort, Line

AU - Singer, David

AU - Stenøien, Hans K.

AU - Tuittila, Eeva Stiina

AU - Vellak, Kai

AU - Waddington, James Michael

AU - Granath, Gustaf

N1 - Publisher Copyright: © 2020 The Authors. Journal of Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society Copyright: Copyright 2021 Elsevier B.V., All rights reserved.

PY - 2021/1

Y1 - 2021/1

N2 - The relative importance of global versus local environmental factors for growth and thus carbon uptake of the bryophyte genus Sphagnum—the main peat-former and ecosystem engineer in northern peatlands—remains unclear. We measured length growth and net primary production (NPP) of two abundant Sphagnum species across 99 Holarctic peatlands. We tested the importance of previously proposed abiotic and biotic drivers for peatland carbon uptake (climate, N deposition, water table depth and vascular plant cover) on these two responses. Employing structural equation models (SEMs), we explored both indirect and direct effects of drivers on Sphagnum growth. Variation in growth was large, but similar within and between peatlands. Length growth showed a stronger response to predictors than NPP. Moreover, the smaller and denser Sphagnum fuscum growing on hummocks had weaker responses to climatic variation than the larger and looser Sphagnum magellanicum growing in the wetter conditions. Growth decreased with increasing vascular plant cover within a site. Between sites, precipitation and temperature increased growth for S. magellanicum. The SEMs indicate that indirect effects are important. For example, vascular plant cover increased with a deeper water table, increased nitrogen deposition, precipitation and temperature. These factors also influenced Sphagnum growth indirectly by affecting moss shoot density. Synthesis. Our results imply that in a warmer climate, S. magellanicum will increase length growth as long as precipitation is not reduced, while S. fuscum is more resistant to decreased precipitation, but also less able to take advantage of increased precipitation and temperature. Such species-specific sensitivity to climate may affect competitive outcomes in a changing environment, and potentially the future carbon sink function of peatlands.

AB - The relative importance of global versus local environmental factors for growth and thus carbon uptake of the bryophyte genus Sphagnum—the main peat-former and ecosystem engineer in northern peatlands—remains unclear. We measured length growth and net primary production (NPP) of two abundant Sphagnum species across 99 Holarctic peatlands. We tested the importance of previously proposed abiotic and biotic drivers for peatland carbon uptake (climate, N deposition, water table depth and vascular plant cover) on these two responses. Employing structural equation models (SEMs), we explored both indirect and direct effects of drivers on Sphagnum growth. Variation in growth was large, but similar within and between peatlands. Length growth showed a stronger response to predictors than NPP. Moreover, the smaller and denser Sphagnum fuscum growing on hummocks had weaker responses to climatic variation than the larger and looser Sphagnum magellanicum growing in the wetter conditions. Growth decreased with increasing vascular plant cover within a site. Between sites, precipitation and temperature increased growth for S. magellanicum. The SEMs indicate that indirect effects are important. For example, vascular plant cover increased with a deeper water table, increased nitrogen deposition, precipitation and temperature. These factors also influenced Sphagnum growth indirectly by affecting moss shoot density. Synthesis. Our results imply that in a warmer climate, S. magellanicum will increase length growth as long as precipitation is not reduced, while S. fuscum is more resistant to decreased precipitation, but also less able to take advantage of increased precipitation and temperature. Such species-specific sensitivity to climate may affect competitive outcomes in a changing environment, and potentially the future carbon sink function of peatlands.

KW - CARBON

KW - CLIMATE

KW - CO2

KW - DEPOSITION

KW - MODEL

KW - MOSSES

KW - NITROGEN

KW - PAR

KW - PHOTOSYNTHESIS

KW - SPHAGNUM GROWTH

KW - WATER

KW - climate

KW - global change

KW - net primary production

KW - nitrogen deposition

KW - peat mosses

KW - plant-climate interactions

KW - structural equation model

KW - plant–climate interactions

UR - http://www.scopus.com/inward/record.url?scp=85091524308&partnerID=8YFLogxK

UR - https://www.mendeley.com/catalogue/cf31d1bc-f16e-315b-973a-b041112f6d32/

U2 - 10.1111/1365-2745.13499

DO - 10.1111/1365-2745.13499

M3 - Article

AN - SCOPUS:85091524308

VL - 109

SP - 417

EP - 431

JO - Journal of Ecology

JF - Journal of Ecology

SN - 0022-0477

IS - 1

ER -