To assess the direction and strength of climate and leaf litter trait effects on decomposition dynamics throughout the litter decomposition process.
We performed a three-year-long litterbag translocation experiment along an elevational gradient in a transitional mixed forest in China. We explored temporal shifts in the relative contribution of microclimate and litter traits of seven dominant species to mass loss throughout the decomposition process.
Air temperature and soil moisture imparted no significant effects on mass loss in the initial decomposition stage (0–6 months) but exerted positive effects after 6 months’ incubation (p < 0.05). Initial specific leaf area (SLA) was positively associated with mass loss only during the early decomposition stages (0–12 months). Litter P concentration was positively while N concentration was negatively associated with mass loss for almost all decomposition stages. Both litter Mg and Ca concentrations were negatively associated with mass loss throughout the whole decomposition process (p < 0.05). The relative contribution of microclimate was weaker than that of litter traits during the early stages but increased in the late decomposition stage (after 36 months). SLA and Mg were the most important traits during the early stages (0-12 months), whereas N and Mg were relatively stronger during the later stages (30–36 months).
Our results have highlighted that microclimate (particularly temperature) exerted dominant control over later-stage litter decomposition. Often-overlooked litter traits such as Mg, are key potential drivers of litter decomposition dynamics and should be more explicitly incorporated into current biogeochemical models to better understand litter-driven nutrient and carbon cycling.