TY - JOUR

T1 - Microclimate explains little variation in year-round decomposition across an Arctic tundra landscape

AU - von Oppen, Jonathan

AU - Assmann, Jakob J.

AU - Bjorkman, Anne D.

AU - Treier, Urs A.

AU - Elberling, Bo

AU - Normand, Signe

N1 - Publisher Copyright: © 2024 The Authors. Oikos published by John Wiley & Sons Ltd on behalf of Nordic Society Oikos.

PY - 2024

Y1 - 2024

N2 - Litter decomposition represents a major path for atmospheric carbon influx into Arctic soils, thereby controlling below-ground carbon accumulation. Yet, little is known about how tundra litter decomposition varies with microenvironmental conditions, hindering accurate projections of tundra soil carbon dynamics with future climate change. Over 14 months, we measured landscape-scale decomposition of two contrasting standard litter types (Green tea and Rooibos tea) in 90 plots covering gradients of micro-climate and -topography, vegetation cover and traits, and soil characteristics in Western Greenland. We used the tea bag index (TBI) protocol to estimate relative variation in litter mass loss, decomposition rate (k) and stabilisation factor (S) across space, and structural equation modelling (SEM) to identify relationships among environmental factors and decomposition. Contrasting our expectations, microenvironmental factors explained little of the observed variation in both litter mass loss, as well as k and S, suggesting that the variables included in our study were not the major controls of decomposer activity in the soil across the studied tundra landscape. We use these unexpected findings of our study combined with findings from the current literature to discuss future avenues for improving our understanding of the drivers of tundra decomposition and, ultimately, carbon cycling across the warming Arctic.

AB - Litter decomposition represents a major path for atmospheric carbon influx into Arctic soils, thereby controlling below-ground carbon accumulation. Yet, little is known about how tundra litter decomposition varies with microenvironmental conditions, hindering accurate projections of tundra soil carbon dynamics with future climate change. Over 14 months, we measured landscape-scale decomposition of two contrasting standard litter types (Green tea and Rooibos tea) in 90 plots covering gradients of micro-climate and -topography, vegetation cover and traits, and soil characteristics in Western Greenland. We used the tea bag index (TBI) protocol to estimate relative variation in litter mass loss, decomposition rate (k) and stabilisation factor (S) across space, and structural equation modelling (SEM) to identify relationships among environmental factors and decomposition. Contrasting our expectations, microenvironmental factors explained little of the observed variation in both litter mass loss, as well as k and S, suggesting that the variables included in our study were not the major controls of decomposer activity in the soil across the studied tundra landscape. We use these unexpected findings of our study combined with findings from the current literature to discuss future avenues for improving our understanding of the drivers of tundra decomposition and, ultimately, carbon cycling across the warming Arctic.

KW - Arctic tundra

KW - carbon cycling

KW - litter decomposition

KW - microclimate

KW - soil moisture

KW - soil temperature

KW - stratified random sampling

KW - structural equation modelling (SEM)

KW - tea bag index (TBI)

U2 - 10.1111/njb.04062

DO - 10.1111/njb.04062

M3 - Journal article

AN - SCOPUS:85182446547

VL - 2024

JO - Opera Botanica

JF - Opera Botanica

SN - 0078-5237

IS - 3

M1 - e04062

ER -