Permafrost collapse after shrub removal shifts tundra ecosystem to a methane source

TY - JOUR

T1 - Permafrost collapse after shrub removal shifts tundra ecosystem to a methane source

AU - Nauta, Ake L.

AU - Heijmans, Monique P.D.

AU - Blok, Daan

AU - Limpens, Juul

AU - Elberling, Bo

AU - Gallagher, Angela

AU - Li, Bingxi

AU - Petrov, Roman E.

AU - Maximov, Trofim C.

AU - van Huissteden, Jacobus

AU - Berendse, Frank

N1 - CENPERM[2015] Cover story Nature Climate Change January 2015 issue

PY - 2015/12/18

Y1 - 2015/12/18

N2 - Arctic tundra ecosystems are warming almost twice as fast as the global average. Permafrost thaw and the resulting release of greenhouse gases from decomposing soil organic carbon have the potential to accelerate climate warming. In recent decades, Arctic tundra ecosystems have changed rapidly, including expansion of woody vegetation, in response to changing climate conditions. How such vegetation changes contribute to stabilization or destabilization of the permafrost is unknown. Here we present six years of field observations in a shrub removal experiment at a Siberian tundra site. Removing the shrub part of the vegetation initiated thawing of ice-rich permafrost, resulting in collapse of the originally elevated shrub patches into waterlogged depressions within five years. This thaw pond development shifted the plots from a methane sink into a methane source. The results of our field experiment demonstrate the importance of the vegetation cover for protection of the massive carbon reservoirs stored in the permafrost and illustrate the strong vulnerability of these tundra ecosystems to perturbations. If permafrost thawing can more frequently trigger such local permafrost collapse, methane-emitting wet depressions could become more abundant in the lowland tundra landscape, at the cost of permafrost-stabilizing low shrub vegetation.

AB - Arctic tundra ecosystems are warming almost twice as fast as the global average. Permafrost thaw and the resulting release of greenhouse gases from decomposing soil organic carbon have the potential to accelerate climate warming. In recent decades, Arctic tundra ecosystems have changed rapidly, including expansion of woody vegetation, in response to changing climate conditions. How such vegetation changes contribute to stabilization or destabilization of the permafrost is unknown. Here we present six years of field observations in a shrub removal experiment at a Siberian tundra site. Removing the shrub part of the vegetation initiated thawing of ice-rich permafrost, resulting in collapse of the originally elevated shrub patches into waterlogged depressions within five years. This thaw pond development shifted the plots from a methane sink into a methane source. The results of our field experiment demonstrate the importance of the vegetation cover for protection of the massive carbon reservoirs stored in the permafrost and illustrate the strong vulnerability of these tundra ecosystems to perturbations. If permafrost thawing can more frequently trigger such local permafrost collapse, methane-emitting wet depressions could become more abundant in the lowland tundra landscape, at the cost of permafrost-stabilizing low shrub vegetation.

U2 - 10.1038/NCLIMATE2446

DO - 10.1038/NCLIMATE2446

M3 - Letter

SN - 1758-678X

VL - 5

SP - 67

EP - 70

JO - Nature Climate Change

JF - Nature Climate Change

ER -