A systematic review of ecological responses to variation in seasonal snow cover

Abstract

Seasonal snow is among the most important factors governing the ecology of many terrestrial ecosystems, but rising global temperatures are changing snow regimes and driving widespread declines in the depth and duration of snow cover. Loss of the insulating snow layer will fundamentally change the environment – far more than incremental temperature increases. Understanding how individuals, populations, and communities respond to different snow conditions is thus essential for predicting and managing future ecosystem change. We conducted a systematic review to synthesize 365 studies that have examined ecological responses to variation in winter snow conditions. This substantial body of research encompasses a broad range of research methods (experimental manipulations, natural snow gradients, and long-term monitoring approaches), locations (35 countries), study organisms (plants, mammals, arthropods, birds, fish, lichen, and fungi), and response measures. Although we found trends towards advanced phenology with earlier snowmelt and greater mortality and/or physical injury with shallower snow, the mechanisms behind these responses remain largely unknown. With 96% of studies from the northern hemisphere, the generality of these trends across ecosystems is also unclear. We identified substantial research gaps and highlight five key areas for future research to better understand the mechanisms underlying responses to changing snow conditions and the consequences of those responses for seasonally snow-covered ecosystems.