Altered Snow Density and Chemistry Change Soil Nitrogen Mineralization and Plant Growth

Abstract

Snow properties such as snow density will likely change in a warmer climate. Changes in depth and extent of snow cover have been shown to affect soil nutrient dynamics and plant growth; however, effects of a changed snow density have so far not been explicitly tested. We altered snow properties (especially depth and density according to those found on ski runs) and investigated effects on soil temperatures, soil nitrogen mineralization, plant phenology, and productivity. A denser, thinner snow cover led to reduced soil insulation and lower soil temperatures, which consequently increased net N mineralization. A denser snow cover furthermore resulted in a delay in plant phenology of up to five weeks after melt-out. The results suggest that changes in snow density, which have been largely neglected in the global change discussion until now, can cause significant changes in soil and vegetation processes.

Radiocarbon Content of CO2 Respired from High Arctic Tundra in Northwest Greenland

“…Experimental snow depth manipulations in Low Arctic, alpine, and grassland ecosystems have provided evidence that changing a landscape's snow depth regime directly influences physical, chemical, and biological processes (Brooks et al, 1996;McGuire et al, 2000;Aerts et al, 2004;Schimel et al, 2004;Chimner and Welker, 2005;Welker et al, 2005, Rixen et al, 2008. The results presented in this study are the first to show the sensitivity of a High Arctic ecosystem to multiple levels of increased winter snow depth.…”

Effect of altered snow conditions on decomposition in three subalpine plant communities

“…Ski slopes have long been found to have an important impact on biota because of profound changes in physical and chemical parameters of the environment [17,21,23,49]. The inferences based on changes in the abiotic parameters that we observed are not straightforward, however.…”

“…Surprisingly, only a limited number of papers have focused on the effects of anthropogenic impact on snow cover and decomposition in mountain environments [16][17][18]. The straightforward evidence of the influence of artificially altered snow conditions on mountain ecosystems comes from studies on ski slopes because ski slope operations unequivocally change snow characteristics [19][20][21].…”

Increased photosynthesis compensates for shorter growing season in subarctic tundra—8 years of snow accumulation manipulations

“…A review over snow manipulation experiments in alpine and arctic environments show that the majority of the experiments run for 3 years or shorter, while some experiments (mainly focused on changes in species composition and phenology) run for longer time periods (4-32 years) (Wipf and Rixen 2010). Several studies have investigated productivity and plant growth (Walker et al 1999;Welker et al 2000;Chimner and Welker 2005;La Puma et al 2007;Rixen et al 2008). However, the results are not all conclusive: Plant biomass has shown to increase with increased snow cover (Walker et al 1995(Walker et al , 1999Wahren et al 2005), but others report a decline in the overall ecosystem productivity due to delayed snowmelt and shortened growing season (Aurela et al 2004;Grøndahl et al 2007;Wipf and Rixen 2010).…”