Early stage of single and mixed leaf-litter decomposition in semiarid forest pine-oak: the role of rainfall and microsite

Abstract

It is well known that inherent characteristics of forest species constitute the main control of litter decomposition. In mixed forest, chemical interactions occurring through precipitation turn mechanisms of litter decomposition very uncertain and difficult to predict. Early-stage leaf litter decomposition of Quercus potosina and Pinus cembroides and their controls were examined based on Ostrofsky's decomposition mechanisms. From June 2007 to May 2008, litterbags with pure and mixed leaf-litter of Q. potosina and P. cembroides were incubated in situ in monospecific and mixed tree stands, respectively. Sampling was carried out 3, 6, 9, and 12 months after incubation. After 12 months, two phases of decomposition of pure and mixed litter were identified; an early phase with a greater rate of mass loss of the labile litter fraction (k L ; soluble compounds) and a later phase with a lower rate of mass loss of the recalcitrant litter fraction (k R ; lignin). The labile fraction lost was observed at three and 6 months of incubation, which coincided with the months of highest rainfall likely triggering a rapid release of soluble carbon compounds from leaf litter. Results also indicate that leaf-litter from Q. potosina had higher concentration of soluble compounds and lower lignin concentration than leaf litter from P. cembroides. Observed facilitative and inhibitory mechanisms for mass loss in Q. potosina and P. cembroides were controlled by interaction between physico-chemical litter characteristics and rainfall.

A comparison of decomposition dynamics among green tree leaves, partially decomposed tree leaf litter and their mixture in a warm temperate forest ecosystem

“…Most studies determining the non-additive effects of litter mixture between contrasting litter species have found that the occurrence of nutrient-rich litter may speed up the decomposition of nutrient-poor litter when they co-occur (Hoorens et al 2003;Pérez-Suárez et al 2012;Ostrofsky 2007). In this study, however, non-additive effects were not apparent when green leaves were mixed with partially decomposed leaf litter at both forest sites, implicating a complex interplay between the effects of litter chemical quality and interactions with decomposers (Pandey et al 2007;Purahong et al 2014).…”

“…In a decomposition study involving needle-leaf litter, broadleaf litter and different combinations of the two litter types, Chapman and Koch (2007) found that differences in mass loss among different decay stages were also greater at a pine site than at an aspen site. The presence of more chemically recalcitrant compounds such as lignin and phenolics in pine needles than in broadleaf litter might explain the much slower rate of decomposition at the pine-oak forest site (Parton et al 2007;Pérez-Suárez et al 2012). Moreover, partially decomposed needle-leaf litter might protect some soluble substances from the effects of abrasion and leaching through a stability mechanism by interaction between recalcitrant compounds and soluble compounds, thereby providing a more persistent habitat for decomposers than broadleaf litter (Ostrofsky 2007).…”

Climatic controls on leaf litter decomposition across European forests and grasslands revealed by reciprocal litter transplantation experiments

“…Vestgarden, 2001) but measure the remaining litter mass in monthly intervals after the beginning of the decomposition. However, there are experiments showing that the remaining mass data over time follows a curvilinear relationship (Pérez-Suárez et al, 2012), thus assuming that the highest mass loss rate occurs during the first days. Our study confirms with experimental data that the mass loss measured at Hyytiälä after 1 month of decomposition is mainly due to the high mass loss occurring in the very first days, being the absolute maximum rate of the decomposition during the whole period.…”

Effect of Litter Quality on Leaf-Litter Decomposition in the Context of Home-Field Advantage and Non-Additive Effects in Temperate Forests in China

“…However, in our study the data indicated that the rate of decomposition of oak litter in the mixtures was barely influenced by neighboring species, while aspen and birch litter in these mixtures decomposed faster than monoculture separately, resulting in an overall weaker positive non-additive effect in mixtures. The possible underlying reason is that the strongly lignified leaf tissue of oak litter could form high structural stability, which could hamper further decomposition of leaf litter [51]. For the aspen or birch litter mixed with oak litter, the decomposition of recalcitrant lignin from oak litter may coincide with the decomposition of labile compounds from aspen or birch litter, which promote enzyme activities toward lignified structures in cell walls so as to decompose more labile compounds in aspen or birch litter [51][52].…”

“…The possible underlying reason is that the strongly lignified leaf tissue of oak litter could form high structural stability, which could hamper further decomposition of leaf litter [51]. For the aspen or birch litter mixed with oak litter, the decomposition of recalcitrant lignin from oak litter may coincide with the decomposition of labile compounds from aspen or birch litter, which promote enzyme activities toward lignified structures in cell walls so as to decompose more labile compounds in aspen or birch litter [51][52].…”