Functional convergence in regulation of net CO2 flux in heterogeneous tundra landscapes in Alaska and Sweden
Article first published online: 16 JUN 2007
Journal of Ecology
Volume 95, Issue 4, pages 802–817, July 2007
How to Cite
SHAVER, G. R., STREET, L. E., RASTETTER, E. B., VAN WIJK, M. T. and WILLIAMS, M. (2007), Functional convergence in regulation of net CO2 flux in heterogeneous tundra landscapes in Alaska and Sweden. Journal of Ecology, 95: 802–817. doi: 10.1111/j.1365-2745.2007.01259.x
- Issue published online: 16 JUN 2007
- Article first published online: 16 JUN 2007
- Received 15 February 2007; revision accepted 11 April 2007 Editor: Matthew Turnbull
- net ecosystem production;
- light response;
- landscape heterogeneity;
- CO2 flux;
- carbon balance
- 1Arctic landscapes are characterized by extreme vegetation patchiness, often with sharply defined borders between very different vegetation types. This patchiness makes it difficult to predict landscape-level C balance and its change in response to environment.
- 2Here we develop a model of net CO2 flux by arctic landscapes that is independent of vegetation composition, using instead a measure of leaf area derived from NDVI (normalized-difference vegetation index).
- 3Using the light response of CO2 flux (net ecosystem exchange, NEE) measured in a wide range of vegetation in arctic Alaska and Sweden, we exercise the model using various data subsets for parameter estimation and tests of predictions.
- 4Overall, the model consistently explains ~80% of the variance in NEE knowing only the estimated leaf area index (LAI), photosynthetically active photon flux density (PPFD) and air temperature.
- 5Model parameters derived from measurements made in one site or vegetation type can be used to predict NEE in other sites or vegetation types with acceptable accuracy and precision. Further improvements in model prediction may come from incorporating an estimate of moss area in addition to LAI, and from using vegetation-specific estimates of LAI.
- 6The success of this model at predicting NEE independent of any information on species composition indicates a high level of convergence in canopy structure and function in the arctic landscape.