Wintertime decomposition dynamics play a significant role in temperate forest nutrient cycling, but it is unknown how these processes will shift in a changing climate. Climate projections for temperate regions predict variable precipitation and higher frequencies of extreme temperature fluctuations, such as accentuated warm and cold events. This may reduce total winter snowpack and its persistence or increase freeze-thaw events, potentially altering dynamics of decomposition within the forest floor. Decomposition of leaf litter is determined by physical conditions, such as snow cover and temperature, as well as decomposer density and their resilience to cold. Previous studies have shown how an established snowpack in the dormant season mediates environmental conditions in leaf litter microclimates, in turn supporting winter-adapted microbial communities. However, nutrient turnover and carbon flux on behalf of leaf litter decomposition under predicted environmental changes is not fully understood. In this short-term litter bag experiment in upstate New York, I compared carbon (C) and nitrogen (N) content, mass loss, and microbial respiration of Acer saccharum leaf litter between the actual environmental conditions and a constant snowpack treatment during the winter months.
Results/Conclusions
Constant snowpack reduced temperature fluctuations by 17%. Over the course of 3 months, mass loss of leaf litter underneath constant snowpack did not show significant differences between treatments, while C:N only showed marginal decrease. Leaf litter respiration was explained to a greater extent by litter water content than differences in treatment or temperature. These results may suggest that persistent snowpack in temperate forests facilitates winter leaf litter decomposition conditions, although on short time scales significant differences are not well detected. My results suggest C:N may be a better predictor in short-term leaf litter decomposition dynamics than mass loss. The predicted changes to abiotic conditions such as temperature and precipitation may result in altered dynamics of leaf litter decomposition in future winters. As climate projections predict more variability, it is increasingly important to understand possible shifts for wintertime decomposition and its impact on annual forest nutrient cycling.