Abstract (eng)
The Arctic is one of the ecosystems most affected by climate change and especially winter temperatures and precipitation sums are supposed to increase. Consequently, snow cover depth and duration, the most important drivers of growing season length in the high Arctic, will also change. Depending on the extent and temporal patterns of temperature and precipitation rise, and the associated partitioning of precipitation sums into rain and snow components, this may either entail a shortened or prolonged snow free period, respectively. These changes will likely have multiple effects on plant productivity and hence the availability of biomass for consumers. In this study, I try to assess how the growth and productivity of eight common high arctic plant species will respond to different predicted climate change scenarios by experimentally changing snowmelt dates. My results demonstrate considerable variation among species with idiosyncratic positive and negative responses of individual species to either accumulation or reduction of snow cover depth and duration. I conclude that generic predictions of effects of a changing snow pack on the productivity of arctic vegetation are hardly possible, at least if a climate change driven species turn-over in local community compositions is not accounted for.