Abstract
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 protocol to estimate relative variation in litter mass
loss, decomposition rate (k ) and stabilisation factor (S )
across space, and Structural Equation Modelling 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 andS , 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 shortcomings 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.