Global negative vegetation feedback to climate warming responses of leaf litter decomposition rates in cold biomes.
Whether climate change will turn cold biomes from large long-term carbon sinks into sources is hotly debated because of the great potential for ecosystem-mediated feedbacks to global climate. Critical are the direction, magnitude and generality of climate responses of plant litter decomposition. Here, we present the first quantitative analysis of the major climate-change-related drivers of litter decomposition rates in cold northern biomes worldwide. Leaf litters collected from the predominant species in 33 global change manipulation experiments in circum-arctic-alpine ecosystems were incubated simultaneously in two contrasting arctic life zones. We demonstrate that longer-term, large-scale changes to leaf litter decomposition will be driven primarily by both direct warming effects and concomitant shifts in plant growth form composition, with a much smaller role for changes in litter quality within species. Specifically, the ongoing warming-induced expansion of shrubs with recalcitrant leaf litter across cold biomes would constitute a negative feedback to global warming. Depending on the strength of other (previously reported) positive feedbacks of shrub expansion on soil carbon turnover, this may partly counteract direct warming enhancement of litter decomposition.
Cornelissen
Johannes H C
JH
Department of Systems Ecology, Faculty of Earth and Life Sciences, Institute of Ecological Science, Vrije Universiteit, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands. hans.cornelissen@ecology.falw.vu.nl
van Bodegom
Peter M
PM
Aerts
Rien
R
Callaghan
Terry V
TV
van Logtestijn
Richard S P
RS
Alatalo
Juha
J
Chapin
F Stuart
FS
Gerdol
Renato
R
Gudmundsson
Jon
J
Gwynn-Jones
Dylan
D
Hartley
Anne E
AE
Hik
David S
DS
Hofgaard
Annika
A
Jónsdóttir
Ingibjörg S
IS
Karlsson
Staffan
S
Klein
Julia A
JA
Laundre
Jim
J
Magnusson
Borgthor
B
Michelsen
Anders
A
Molau
Ulf
U
Onipchenko
Vladimir G
VG
Quested
Helen M
HM
Sandvik
Sylvi M
SM
Schmidt
Inger K
IK
Shaver
Gus R
GR
Solheim
Bjørn
B
Soudzilovskaia
Nadejda A
NA
Stenström
Anna
A
Tolvanen
Anne
A
Totland
Ørjan
Ø
Wada
Naoya
N
Welker
Jeffrey M
JM
Zhao
Xinquan
X
D000704:Analysis of Variance; D002244:Carbon / Q000737:chemistry; D003081:Cold Climate; D017753:Ecosystem; D017752:Greenhouse Effect; D008954:Models, Biological; D063245:Plant Development; D018515:Plant Leaves / Q000378:metabolism*; D010944:Plants / Q000378:metabolism; D013045:Species Specificity; D013548:Sweden
D002244:Carbon