Vascular plant species response to warming and elevated carbon dioxide
in a boreal peatland
The Spruce and Peatland Responses Under Changing Environments (SPRUCE)
project is a warming and elevated carbon dioxide (CO2) experiment
designed to test how peatland ecosystems will respond to climate change.
Here, we report changes in the vascular plant community during the first
five years of SPRUCE. We tracked species composition, diversity, and
aboveground net primary production (ANPP) in chambers warmed at a wide
range of temperatures (+0, +2.25, +4.5, +6.75, +9 ˚C), and two CO2
levels (~400 [ambient] and 900 parts per million).
We observed an increase in aboveground vascular plant biomass
accumulation, due primarily to an increase in shrub abundances. Overall
species diversity decreased substantially, likely due in part to shading
by a denser shrub canopy. These results indicate an overall increase in
NPP with warming, but highlight the importance of interactions between
direct (warming) and indirect (competition) effects in determining how
boreal ecosystems will respond to climate change.