Data and code from: Inverse effects of soil moisture and litter quality on litter decomposition along a gradient from hyper-arid to temperate climate

Litter decomposition, a key component of the global carbon cycle, is
greatly affected by climate. Our current understanding of climate-change
effects on decomposition stems from 1) spatial observational studies along
climate gradients, where direct and indirect effects of climate on litter
decomposition are confounded; 2) reciprocal litter translocations and
common garden experiments, where biotic interactions are disrupted or 3)
manipulation experiments, which can be less realistic than observational
studies. Experimental studies combining all of the above-mentioned methods
can separate indirect from direct climate effects on decomposition, as the
confounding effects of one method can be explained with another method.
Additionally, this setup can directly test if observations along a spatial
gradient can predict responses to climate change, i.e. the validity of the
space-for-time approach. However, studies combining the different methods
are still scarce. We combined a pronounced climate gradient, large- and
small-scale reciprocal litter translocations (local litter and standard
litter, i.e. tea), and in situ precipitation manipulation for studying
soil moisture effects on litter decomposition. All our experiments
(translocation of litter and tea across the gradient, slope comparisons
within sites, and rainfall exclusions) indicated positive direct effects
of climate on litter decomposition. However, as local litter quality
decreased with increasing precipitation, litter from species of the drier
sites decomposed quicker than litter from species of the wetter sites
across the gradient. In other words, while the direct effects of climate
favoured litter decomposition in wetter sites, its indirect effect (i.e.
litter quality) favoured the decomposition of litter from species of the
drier sites within each site. Synthesis: Our results highlight the need
for experimental evidence from reciprocal translocations and climate
manipulations in litter decomposition studies as they indicate that space
cannot always substitute for time. Such evidence would improve predictions
of models of the global carbon cycle that include interactions between
climate and vegetation.