The ecological stoichiometry and interrelationship between litter and soil under seasonal snowfall in Tianshan Mountain

Abstract

AbstractChanges in snow cover caused by global climate change will profoundly affect the process of litter decomposition and soil nutrient cycling in terrestrial ecosystems. The presence of seasonal snow cover during the winter has a significant impact on forest ecosystems. The goals of this study were to explore how seasonal snow cover modulates litter decomposition dynamics and elemental cycling in forest ecosystems, and to characterize the ecological stoichiometry of nutrients in the leaf litter and soils over time. Seasonal snowfall leads to different snow depths on the ground, especially when comparing forest gaps to closed canopy. Snow cover in this study was categorized as absent, thin, intermediate, and thick according to depth (n = 4 treatments). Leaf litter and underlying soils were sampled in plots from each category of snow cover over the course of multiple seasons (i.e., the freeze–thaw period, deep‐freeze period, thaw period, pre‐growth season, and late growth season). The carbon, nitrogen, and phosphorus concentration of leaf litter and soils were determined at each stage. The litter decomposition rate and nutrient concentration were largely dependent on the thickness of the snowpack formed by seasonal snowfall. Overall, variability in the ecological stoichiometry of elements in the leaf litter and soils was small. However, in the leaf litter, carbon, nitrogen, and phosphorus concentrations and their stoichiometric ratios differed across the snow cover gradient during the winter when snow was present, but not when snow was absent in the warmer months. Thicker snowpacks better maintained litter decomposition and kept nutrient levels stable. Furthermore, correlations between leaf litter and soil ecological stoichiometry were affected by seasonal snow cover, with element concentration also varying over time.