Divergent responses of carbon-degrading enzyme activities to litter
alterations: Implications for soil respiration
Abstract
Global change affects terrestrial litter inputs with cascading effects
on soil respiration (SR). Cellulase and ligninase are dominant
carbon-degrading enzymes, targeting the decomposition of readily
decomposable and structurally complex carbon pools, respectively.
Nevertheless, how litter alterations influence cellulase and ligninase
activities and the implications for SR remain unclear. We conducted a
meta-analysis to show that litter addition increased cellulase activity
by 25.2%, whereas litter removal decreased it by 25.9%. Neither litter
addition nor removal influenced ligninase activity. The changes in
cellulase activity correlated positively with changes in SR, but not for
ligninase activity. The effects of litter addition and removal on
cellulase activity decreased with treatment duration. These results
indicate that litter alterations affect SR primarily by controlling the
microbial decomposition of readily decomposable rather than structurally
complex carbon pools. Altogether, we suggest that the total and
long-term effects of litter alterations on SR might be smaller than
previously thought.