Litter decomposition, a key component of the global carbon cycle, is
greatly affected by climate. Unfortunately, our current understanding of
climate-change effects on decomposition stems mainly from space-for-time
studies along climate gradients, where biotic and climatic effects on
litter decomposition are confounded. Experimental studies separating
indirect from direct climate effects are needed that test the validity
of the space-for-time approach. Here, we combined large- and small scale
reciprocal litter translocations, in situ precipitation manipulation,
and a prominent climate gradient for studying drought effects on litter
decomposition. Interestingly, all experiments indicated clear positive
effects of precipitation on decomposition, but the space-for-time
approach indicated the opposite, due to indirect climate effects on
litter quality. This indicates that space cannot substitute for time and
highlights the need for experimental evidence in litter decomposition
studies. Such evidence would improve predictions of models of the global
carbon cycle that include interactions between climate and vegetation.