Experimental Warming and its Effects on Sphagnum Traits and Community Composition in Boreal Peatlands
Abstract
Plant community composition, of particularly the Sphagnum mosses, is a key regulator of peatland ecosystem dynamics. Sphagnum traits related to growth and water-holding/acquisition dynamics will determine species-specific responses to increases in temperature. To understand plant community dynamics in response to seven years of experimental field warming, I quantified the composition of the vascular and bryophyte communities and measured key Sphagnum traits. I found that the frequency of bare peat increased under warming indicating a loss of Sphagnum coverage, specifically I observed decreases in the abundance of the Sphagnum species S. angustifolium. In warmed plots I also found trends of decreasing S. fuscum, but slight increases in S. divinum that are likely related to water holding capacity traits. My results suggest a transition of peatland plant community composition that may have consequences for the stability of these ecosystems as they experience climate change.