Cellulose Dynamics during Foliar Litter Decomposition in an Alpine Forest Meta-Ecosystem

Abstract

Abstract:To investigate the dynamics and relative drivers of cellulose degradation during litter decomposition, a field experiment was conducted in three individual ecosystems (i.e., forest floor, stream, and riparian zone) of an alpine forest meta-ecosystem on the eastern Tibetan Plateau. Four litter species (i.e., willow: Salix paraplesia, azalea: Rhododendron lapponicum, cypress: Sabina saltuaria, and larch: Larix mastersiana) that had varying initial litter chemical traits were placed separately in litterbags and then incubated on the soil surface of forest floor plots or in the water of the stream and riparian zone plots. Litterbags were retrieved five times each year during the two-year experiment, with nine replicates each time for each treatment. The results suggested that foliar litter lost 32.2%-89.2% of the initial dry mass depending on litter species and ecosystem type after two-year's incubation. The cellulose lost 60.1%-96.8% of the initial mass with degradation rate in the order of stream > riparian zone > forest floor. Substantial cellulose degradation occurred at the very beginning (i.e., in the first pre-freezing period) of litter decomposition. Litter initial concentrations of phosphorus (P) and lignin were found to be the dominant chemical traits controlling cellulose degradation regardless of ecosystems type. The local-scale environmental factors such as temperature, pH, and nutrient availability were important moderators of cellulose degradation rate. Although the effects of common litter chemical traits (e.g., P and lignin concentrations) on cellulose degradation across different individual ecosystems were identified, local-scale environmental factors such as temperature and nutrient availability were found to be of great importance for cellulose degradation. These results indicated that local-scale environmental factors should be considered apart from litter quality for generating a reliable predictive framework for the drivers of cellulose degradation and further on litter decomposition at a global scale.

Assessing the temporal dynamics of aquatic and terrestrial litter decomposition in an alpine forest

“…This pattern was even more obvious during the early decomposition stages, when substantial amounts of water‐soluble substances (e.g., carbohydrates, phenolics and free amino acids) can lost as a result of the higher leaching and flushing effects found in streams (Berg & McClaugherty, ). Recent studies found that recalcitrant components, such as lignin, can also be substantially degraded during early decomposition stages (Yue, Peng, et al., ; Yue, Wu, et al., ). As lignin degradation is controlled by the availability of easily decomposable carbon sources (Klotzbücher, Kaiser, Guggenberger, Gatzek, & Kalbitz, ), the rapid decline of these labile C compounds in streams may also accompany higher lignin degradation rates.…”

Effects of Predominant Tree Species Mixing on Lignin and Cellulose Degradation during Leaf Litter Decomposition in the Three Gorges Reservoir, China

“…However, a debate has also arisen regarding lignin and cellulose loss. Recent studies declared that a greater loss rate can also be found during the early phase of decomposition due to microenvironmental factors, such as hydrology [10], snow cover [4,5], and solar radiation [11], which can influence the degradation process directly or indirectly. However, the effects of species mixing on lignin and cellulose degradation have seldom been reported to date.…”

Abnormal Litter Induced by Typhoon Disturbances Had Higher Rates of Mass Loss and Carbon Release than Physiological Litter in Coastal Subtropical Urban Forest Ecosystems

“…This indicates that carbon accumulates during the litter decomposition process, possibly because the decomposition rate of material with other elemental concentrations of the litter is greater than the carbon release rate at this phase. It is accompanied by the accumulation of recalcitrant material (such as lignin and condensed phenolic compounds) that is difficult to decompose [68,69], leading to an increase in the proportion of carbon in the total weight of the litter, manifested as litter carbon concentration increase and carbon accumulation. Therefore, as mentioned above, typhoons drive material cycle processes in subtropical urban forests by altering the production and quality of litter, increasing the rate of mass loss and carbon release from litter.…”