Snowmelt timing affects short‐term decomposition rates in an alpine snowbed

Abstract

AbstractAlpine snowbed communities are characterized as having areas of longer lasting snow cover duration compared with the surrounding landscape. The predictable accumulation of deep and long‐lasting snow on lee side ridges drives a unique ecology, providing stable microclimatic conditions under the snow through winter, supplying meltwater in spring, and controlling many biological processes. The timing and rate of plant litter decomposition are key controls on the nutrient balance of snowbed communities, and are thought to be strongly driven by snow dynamics. However, little is known about how the patterns and timing of snowmelt affect decomposition, nor how long these effects last into the growing season. We investigated the influence of snowmelt timing on decomposition rates across an alpine snowbed community by burying standardized plant litter (rooibos and green tea), at three incubation times (whole year, winter+spring, and summer), across three snowmelt zones. Decomposition rate (as percent mass loss of tea) was significantly higher in early‐melting zones compared to late‐melting zones, particularly for the recalcitrant litter (rooibos tea). Decomposition was also affected by the season(s) of incubation and was greatest where tea was buried for the whole year, or only over summer, with winter + spring only incubations decomposing the least. However, decomposition was more strongly influenced by litter quality (type of tea) than either the timing of snowmelt or seasonality. These results provide further understanding about how changes to the timing of snowmelt may in turn transform these rare and unique plant communities.