Vegetation Succession, Carbon Accumulation and Hydrological Change in Subarctic Peatlands, Abisko, Northern Sweden

Abstract

High‐resolution analyses of plant macrofossils, testate amoebae, pollen, mineral content, bulk density, and carbon and nitrogen were undertaken to examine the late Holocene dynamics of two permafrost peatlands in Abisko, Subarctic Sweden. The peat records were dated using tephrochronology, 14C and 210Pb. Local plant succession and hydrological changes in peatlands were synchronous with climatic shifts, although autogenous plant succession towards ombrotrophic status during peatland development was also apparent. The Marooned peatland experienced a shift ca. 2250 cal yr BP from rich to poor fen, as indicated by the appearance of Sphagnum fuscum. At Stordalen, a major shift to wetter conditions occurred between 500 and 250 cal yr BP, probably associated with climate change during the Little Ice Age. During the last few decades, the testate amoeba data suggest a deepening of the water table and an increase in shrub pollen, coinciding with recent climate warming and the associated expansion of shrub communities across the Arctic. Rates of carbon accumulation vary greatly between the sites, illustrating the importance of local vegetation communities, hydrology and permafrost dynamics. Multiproxy data elucidate the palaeoecology of S. lindbergii and show that it indicates wet conditions in peatlands. Copyright © 2017 John Wiley & Sons, Ltd.

Inconsistent Response of Arctic Permafrost Peatland Carbon Accumulation to Warm Climate Phases

“…Both Russian and Finnish sites suggest habitat changes towards drier communities over recent decades. A similar trend was also found previously in northern Sweden (Gałka et al, ). Chronologically, this habitat change corresponds to extensive permafrost degradation reported for the last approximately 50 years (Jones et al, ; Kokfelt et al, ).…”

“…In this study we did not find a significant relationship between ACARs and the moisture index P/Eq. However, this does not preclude the importance of moisture on ACARs when associated to local‐scale permafrost peatland dynamics (Gałka et al, ; Swindles et al, ; Zhang et al, ).…”

Pathways for Ecological Change in Canadian High Arctic Wetlands Under Rapid Twentieth Century Warming

“…We suggest the increase in GDD 0 is the most plausible mechanism driving this shift to shrub dominance at our site. The role of climate is further supported by evidence of a recent increase in shrub taxa in sub‐Arctic permafrost peatlands in Sweden (Gałka, Szal, et al, ) and Alaska (Gałka et al, )—areas of limited isostatic uplift (Geruo et al, ; Peltier, ).…”

Ecology of peatland testate amoebae in the Alaskan continuous permafrost zone

“…Alternatively, surface peat may insulate permafrost below and limit such degradation (Mann et al, 2010). Palaeoecological approaches have been used to identify recent hydrological changes in domed permafrost peatlands, including conversion to inundated Arctic fen systems (Swindles et al, 2015a;Gałka et al, 2017). The associated changes in vegetation structure (Christensen et al, 2004) and hydrology (Quinton et al, 2011), combined with continued warming, are likely to promote elevated methane release from degrading permafrost peatlands, with feedbacks to the global climate system.…”