High Arctic plant community resists 15 years of experimental warming

Summary

1. Identifying plant communities that are resistant to climate change will be critical for developing accurate, wide-scale vegetation change predictions. Most northern plant communities, especially tundra, have shown strong responses to experimental and observed warming.

2. Experimental warming is a key tool for understanding vegetation responses to climate change. We used open-top chambers to passively warm an evergreen-shrub heath by 1.0–1.3 °C for 15 years at Alexandra Fiord, Nunavut, Canada (79 °N). In 1996, 2000 and 2007, we measured height, plant composition and abundance with a point-intercept method.

3. Experimental warming did not strongly affect vascular plant cover, canopy height or species diversity, but it did increase bryophyte cover by 6.3% and decrease lichen cover by 3.5%. Temporal changes in plant cover were more frequent and of greater magnitude than changes due to experimental warming.

4. Synthesis. This evergreen-shrub heath continues to exhibit community-level resistance to long-term experimental warming, in contrast to most Arctic plant communities. Our findings support the view that only substantial climatic changes will alter unproductive ecosystems.