PARENT SESSION
Oral Session #69: Elevated CO₂ and Global Change. Presiding: L. Gough.
Thursday, August 9, 2001. 1:00 PM to 4:45 PM. Hall of Ideas H.

Environmental variation, vegetation distribution, carbon dynamics, and water/energy exchange in high latitudes .

McGuire, A. David¹, Working Group, The IGBP High Latitude Transects², ^{1 2}

ABSTRACT- In this study, we evaluated how vegetation distribution, carbon dynamics, and water and energy exchange are related to environmental variation spanned by the network of the IGBP high latitude transects. While the most notable feature of the high latitude transects is that they generally span temperature gradients from southern to northern latitudes, there are substantial differences in temperature among the transects. Also, along each transect temperature co-varies with precipitation and photosynthetically active radiation, which are also variable among the transects. Although there are similar sequences of vegetation transitions along these gradients, there is variance in climatic associations with vegetation transitions among the transects. Both climate and disturbance interact to influence latitudinal patterns of vegetation and soil carbon storage among the transects, and vegetation distribution appears to be the most important factor in determining exchanges of heat and moisture in high latitudes. The analyses in this study have taken an important step toward coordination of global change studies among the high latitude transects. Coordinated studies have the potential to substantially improve understanding of controls over vegetation dynamics, carbon dynamics, and water and energy exchange in high latitudes in ways that will further clarify the role of high latitude ecosystems in the earth system.

KEY WORDS: Global Change, Climate Change, Vegetation Dynamics, Carbon Cycling