Natural variation in snow depth and snow melt timing in the High Arctic have implications for soil and plant nutrient status and vegetation composition

Abstract

Snow cover is a key component in Arctic ecosystems and will likely be affected by changes in winter precipitation. Increased snow depth and consequent later snowmelt leads to greater microbial mineralization in winter, improving soil and vegetation nutrient status. We studied areas with naturally differing snow depths and date of snowmelt in Adventdalen, Svalbard. Soil properties, plant leaf nutrient status and species composition along with vegetation indices (NDVI) were compared for three snowmelt regimes (Early, Mid and Late). We showed 1) Late regimes (snow beds) had wetter soils, higher pH and leaves of Bistorta vivipara and Salix polaris had higher concentration of nutrients (nitrogen and δ15N). Little to no difference was found in soil nutrient concentrations between snowmelt regimes. 2) Late regimes had highest NDVI values, while those of Early and Mid regimes were similar 3) vegetation composition differed between Early and Late regimes, with Dryas octopetala and Luzula arcuata subsp. confusa characterizing the former and Equisetum arvense and Eriophorum scheuchzeri the latter. 4) Trends for plant nutrients contents were similar to those found in a nearby snow manipulation experiment. Snow distribution and time of snowmelt played an important role in determining regional environmental heterogeneity, patchiness in plant community distribution, their species composition and plant phenology.