Evaluating annual carbon dioxide exchange between the atmosphere and shrub tundra in Canada's Southern Arctic
Mandryk, R.R. 2025.
Abstract
The carbon cycle of Arctic tundra ecosystems is expected to change as the climate warms
and shrub vegetation expands. However, there are few studies that have compared full year carbon
fluxes over tundra with different shrub cover. In this study, soil respiration was measured year-
round using forced-diffusion chambers and ecosystem-scale net ecosystem exchange of CO2
(NEE) was measured from spring through fall using eddy covariance towers at three Canadian
tundra sites with varying dwarf birch shrub cover. Soil respiration was larger at the site with most
shrubs during most months except winter when soil CO2 emissions were similarly small at all three
sites. Although there was more growing season net CO2 uptake at the site with more shrubs,
relatively large emissions in spring and fall offset this sink strength so that all three sites were
similarly small annual net sinks of CO2 (-19 to -31 g C m-2)
