Tundra Vegetation Dynamics: Three Decades of Monitoring + Warming Experiments by the International Tundra Experiment

Rapid climate warming in tundra regions is expected to lead to widespread shifts in the composition, diversity, and phenology of tundra vegetation. Valuable evidence of the changes that have occurred so far comes from the International Tundra Experiment, an international network of researchers who have conducted vegetation monitoring and warming experiments at multiple tundra locations as early as 1992. In this talk I will briefly discuss results from recent and ongoing studies investigating responses to warming and long-term trends in the species & functional composition, phenology, and diversity of tundra plant communities. We find that responses to warming and changes over time often vary by site and species or functional group, but several responses emerge with remarkable consistency. These include a nearly ubiquitous increase in the height of tundra plant communities and an advancement in spring phenology in response to experimental - but not always ambient - warming. When responses to warming vary by species, this variation can often be explained by a species' functional or phenological traits (e.g. height, phenological niche). These changes have implications for shifts in the functioning of tundra ecosystems, including rates of organic matter decomposition, carbon cycling, and interactions with pollinators.