Autumn leaf senescence in tundra plants: Do soil nutrients and plant-internal nutrient sinks influence timing? (RiS ID: 12335)

Plant growth season in Arctic regions is currently undergoing changes, with spring advancement across the Arctic. However, there is limited knowledge regarding any corresponding trends in the autumn season, where the timing of end-of-season is mostly unaccounted for. It is important that we take steps to understand the drivers of end-of-season plant phenology such that we may predict the state of Arctic ecosystems and related climatic processes in the future. With nutrient levels increasing in Arctic soils under permafrost thaw and altered nutrient mineralization rates, it may be hypothesized that increased nutrients could drive a delay in autumn senescence timing (and thus prolonging growing season) under climate change. As of yet, the role of nutrients in senescence phenology has not yet been thoroughly investigated at an Arctic field site. With my current project, I will take a crucial step towards filling this gap. I propose to explicitly test the effects of nutrient addition, and plant-internal nutrient sink (flower) removal, on leaf senescence timing in common tundra plant species in Adventdalen, Svalbard, in a field experiment in the summer 2024.