High Arctic plant community resists 15 years of experimental warming

Abstract

Summary1. 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 longterm experimental warming, in contrast to most Arctic plant communities. Our findings support the view that only substantial climatic changes will alter unproductive ecosystems.

Community assembly responses to warming and increased precipitation in an early successional forest

“…The role of climate in structuring communities and ecosystems is evident in paleobotanic records as well as modern shifts in species distribution that correlate with warming temperatures (Bugmann 1996, Jackson and Overpeck 2000, Woodall et al 2009). Recent research on climate-induced changes in species distribution focuses on ecotones such as alpine tree lines where climate restrictions of species survival and community assembly are clear (e.g., Beckage et al 2008, Hudson andHenry 2010). In more temperate climates, such as in the eastern United States, plant responses to climate are mediated by many biotic and abiotic factors.…”

“…Despite the generally short-term and small-scale nature of these experiments, they allow us to attribute changes in ecosystem structure or function to climate. Past studies of climate effects on community composition compared dominance of broad plant groups such as C3 and C4 grasses at key stages in the experiment (Hudson and Henry 2010, Kardol et al 2010a, Yang et al 2011. The use of plant functional groups allows comparison of climate treatment sensitivities in the face of varying species composition.…”

Thermo-erosion gullies boost the transition from wet to mesic tundra vegetation

“…The secondary succession pioneered here by the gullying process in disturbed polygons follows the directional-species replacement model examined by Svoboda and Henry (1987). However, by occurring within 5 to 10 years, it has been remarkably more rapid than what is usually documented for the High Arctic where perennial plant communities are largely resistant to disturbance Jonsdottir et al, 2005;Hudson and Henry, 2010) and succession dynamics are slow due to short growing seasons and low summer temperatures (Svoboda and Henry, 1987). For instance, plant cover of northeastern Alaska changed little over a 25-year period despite a significant rise in summer temperatures (J. C. .…”

“…Many observational and experimental studies have highlighted shifts in tundra plant community structure and plant species productivity in response to warming temperatures (Jonsdottir et al, 2005;Hudson and Henry, 2010;Epstein et al, 2013;Naito and Cairns, 2015). In contrast, little is known about how thermo-erosion gullying affects plant community structure and plant species abundance.…”

Parameter Sensitivity of the Arctic Biome–BGC Model for Estimating Evapotranspiration in the Arctic Coastal Plain

“…Bryophytes and lichens are generally expected to respond negatively to climate warming at subarctic latitudes, often due to shading by dwarf shrubs (Cornelissen et al, 2001;van Wijk et al, 2004;Walker et al, 2006;Wookey et al, 2009). Bryophyte cover has also increased in response to experimental warming and nu-506 / ARCTIC, ANTARCTIC, AND ALPINE RESEARCH trient addition at high arctic latitudes (Gordon et al, 2001;Hudson and Henry, 2010). Improving the representation of vegetation, including non-vascular vegetation in climate and ecosystem models, is a complex and ongoing challenge that is critical for understanding vegetation-climate interactions in an era of global change.…”