ITEX: Canopy structure and CO2 exchange of arctic ecosystems

The broad theme of this research is the regulation of the primary production system in arctic landscapes and especially the controls at the whole vegetation level. Vegetation is a key regulator of feedbacks from the arctic land surface to the regional and global systems, and plays a central role in mediating responses of the arctic landscape to disturbance and change of all kinds. Species composition and physical structure are among the principal determinants of the arctic land surface energy balance, of the terrestrial water budget, of nutrient inputs to aquatic systems, and of the exchanges of carbon dioxide and other trace gases with the atmosphere.

The current goals are:

  1. What is the relationship between canopy N content, canopy photosynthetic area, and canopy photosynthesis (GPP) in arctic vegetation including both Low and High Arctic sites?

a) Does this relationship change predictably with climate or latitude, or in ecosystems that are changing in species composition and canopy structure?

b) Can we develop a single parameterization of this relationship that is useful in predicting GPP across the full range of arctic ecosystem types, or must we use different parameterizations to predict GPP at different arctic latitudes or climates?

  1. What is the relationship between RE, RA, and RH, in arctic ecosystems and how does it change in space and time?

a) In relatively stable arctic ecosystems does this relationship vary predictably with climate, latitude, vegetation composition, and canopy structure?

b) Can we predict the changes in RE and its components as weather, climate, and vegetation composition change?