Temporal Dynamics of Leaf Litter Components during Decomposition of an Aromatic Shrub Cistus Monspeliensis L.

Litter decomposition in shrubland ecosystems is relatively not well understood, yet they cover significant proportion of the earth surface. The aim of the study is to understand the litter decomposition process of shrubland leaf litter under controlled conditions using litter bag technique over 360 days period. Destructive sampling was done at 0, 15, 30, 60, 90, 120, 150, 180, 270 and 360 days after the incubation and accumulated mass loss (AML) was calculated. We also examined release, retention or accumulation of the various nutrients, change in soluble compound, hemicellulose, cellulose and lignin concentrations in the residual litter. AML displayed a bi-phasic pattern with initial rapid phase, followed by a steady phase. AML best fitted to a double exponential decay model and decay constant for the rapid phase was approximately 130 times higher than the slower phase. Among the nutrients rapid release of P and K was observed. Soluble component concentrations decreased rapidly whereas hemicellulose concentrations slowly decreased. Conversely, lignin concentrations increased throughout the study; however cellulose concentrations are broadly stable. Litter AML best correlated to the temporal dynamics of Lignin-to-N ratio during the decomposition. Overall, 44% of the litter remain in the soil after 360 d of incubation period. Our results suggest that Cistus leaf litter contributes 8.3 kg ha⁻¹d⁻¹ C to below ground. However, details of Cistus species distribution and phenology need to be considered before these results are extrapolated to shrubland ecosystem.