Colorado mountains

Effects of increased snow on growth response and allocation patterns of arctic plants

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Claire Addis
M. Syndonia Bret-Harte

Warming in the Arctic has led to an increase in shrub cover on the tundra and has been well documented in arctic Alaska.  Fall and winter precipitation are also predicted to increase in arctic regions under continued climate change, resulting in greater snow depths.  Increased snow may alter plant growth by insulating winter soil and facilitating overwinter nitrogen mineralization by microbes, thereby increasing nutrients available to plant at spring thaw and influencing growth patterns.   I am studying the effects of increased snow in the arctic, using three snow fences located across a gradient of shrub height and density at Toolik Field Station to compare plant growth on either side of the fences. Growth and allocation measurements include measurements of yearly woody elongation, secondary growth, leaf mass and area measurements, and nutrient analysis of stems and leaves. Overall, there was little difference in growth between plants on drift and non-drifts sides of  snow fences , though it appears that snow addition caused a slightly greater response in woody species as vegetation type increased in height and density (low to tall shrub).  Secondary growth (radial increment) was slightly greater in stem segments formed after snow fences were constructed, indicating increased allocation to secondary tissues in response to snow increases.  Trends indicate that climate change leading to increased snowfall may enhance plant growth for the majority of tundra species, and may thus affect related ecological processes, including ecosystem carbon and nitrogen storage, decomposition rates influenced by litter quality, and physical changes in plant community structure, and consequently atmospheric energy dynamics through potential increases through the reduction of winter albedo.  Each of these ecosystem processes is closely linked with aspects of climate change and has the potential to positively feed back into global warming.




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Background Photo by: Nicole Hansen - Jornada (JRN) LTER