IAB Research Project Description

Collaborative Research: On Snow-Shrub Interactions in Alaskan and Canadian Tundra and their Positive Feedbacks to Vegetation and Climate Change

Ecosystems develop and change through a complex set of interactions between biotic constituents and physical factors. A shift in vegetation architecture is one of the most important state changes that can take place in an ecosystem, because it can radically alter the exchange of energy, water and elements between the geosphere, biosphere and atmosphere.

In the Arctic, recent climate warming is coincident with a substantial expansion in the area occupied by large deciduous shrubs. This land-surface change in vegetation could have profound implications for surface energy balance and the carbon budget of the Arctic. Dominance of shrubs in experimentally fertilized tundra coincides with substantial losses of soil carbon to the atmosphere, though the mechanism by which this has occurred is not yet clear.

A key question is whether shrubs will come to dominate the arctic tundra landscape, and what the implications of this vegetation change would be for biogeochemical cycling and feedbacks to further global and regional climate warming. It has been suggested that the interaction between shrubs and snow in winter may promote their expansion in summer, but it is still unclear how important winter processes might be in promoting shrub dominance.

Our objective in this proposal is to understand how snow-shrub interactions and winter processes might contribute to expansion of shrubs in the Arctic, and the consequences of such vegetation change for biogeochemical cycling of C and N.

Project Funding

National Science Foundation
30 Jun 2005 – 30 Apr 2008
IAB Proposal #05-049
UAF Grant #G2718
IAB Project #113

Media Contact

Marie Thoms
Communications/Web Manager
Institute of Arctic Biology
302A Irving I
University of Alaska Fairbanks
Fairbanks, AK 99775-7000
email: methoms@alaska.edu
phone: 907.474.7412