Northern peatland Collembola communities unaffected by three summers of simulated extreme precipitation

• Extreme climate events are observed and predicted to increase in frequency and duration in high-latitudeecosystems as a result of global climate change. This includes extreme precipitation events, which maydirectly impact on belowground food webs and ecosystem functioning by their physical impacts and byaltering local soil moisture conditions.We assessed responses of the Collembola community in a northern Sphagnum fuscum-dominatedombrotrophic peatland to three years of experimentally increased occurrence of extreme precipitationevents. Annual summer precipitation was doubled (an increase of 200 mm) by 16 simulated extremerain events within the three months growing season, where on each occasion 12.5 mm of rain was addedwithin a few minutes. Despite this high frequency and intensity of the rain events, no shifts in Collemboladensity, relative species abundances and community weighted means of three relevant traits (moisturepreference, vertical distribution and body size) were observed. This strongly suggests that the peatlandCollembola community is unaffected by the physical impacts of extreme precipitation and the short-termvariability in moisture conditions. The lack of response is most likely reinforced by the fact that extremeprecipitation events do not seem to alter longer-term soil moisture conditions in the peat layers inhabitedby soil fauna.This study adds evidence to the observation that the biotic components of northern ombrotrophicpeatlands are hardly responsive to an increase in extreme summer precipitation events. Given the importance of these ecosystems for the global C balance, these findings significantly contribute to the currentknowledge of the ecological impact of future climate scenarios. (C) 2014 Elsevier B.V. All rights reserved.

Ämnesord

NATURVETENSKAP  -- Biologi -- Ekologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Ecology (hsv//eng)

Nyckelord

Extreme events

Precipitation

Soil fauna

Peat bog

Functional traits

Community weighted mean

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