Leaf economics spectrum prevails over nutrient resorption in regulating the temperature sensitivity of litter decomposition in a subtropical forest ecosystem

The LES and nutrient resorption are thought to jointly modulate leaf litter traits, including the litter decomposition, but it is unknown how the two factors affect the temperature sensitivity of litter decomposition (Q(10)). The Q(10) of litter decomposition was evaluated for 15 co-occurring subtropical woody species under laboratory conditions. The LES of these species, as well as species-specific N (NRE) and P resorption efficiency (PRE) during leaf senescence, were also determined. Results showed that the Q(10) values were significantly correlated to LES, with litters from resource-conservative species having higher Q(10) values than those from resource-acquisitive species. Among the parameters characterizing LES, leaf N concentration, C:N ratio, and lignin:N ratio were correlated to Q(10), whereas leaf P and lignin concentrations, specific leaf area, and C:P ratio showed no relationships. The LES was correlated to litter C:N and lignin:N ratios, and, in turn, litter C:N and lignin:N ratios were correlated to Q(10). This result suggested that LES affects litter quality and thus the Q(10) of litter decomposition. However, NRE and PRE were not correlated to Q(10). In addition, the LES effects on litter quality and the Q(10) of decomposition did not depend on nutrient resorption, as indicated by the lack of correlation between LES and NRE or PRE. Our results reveal an association between plant functional features and forest C dynamics in a warmer future.

Automated summary

The effects of leaf economic spectrum (LES) and nutrient resorption on litter decomposition temperature sensitivity (Q(10)) were investigated in 15 subtropical woody species. The results showed that Q(10) values were correlated with LES, with resource-conservative species having higher Q(10) values. Leaf nitrogen concentration, C:N ratio, and lignin:N ratio were correlated with Q(10), while leaf phosphorus and lignin concentrations, specific leaf area, and C:P ratio showed no relationships. Also, there was no correlation between LES and species-specific nitrogen and phosphorus resorption efficiency (NRE and PRE) with Q(10). These findings suggest an association between plant functional features and forest carbon dynamics in a warmer future.