title: Climate change drives a shift in peatland ecosystem plant community: implications for ecosystem function and stability.
abstract: The composition of a peatland plant community has considerable effect on a range of ecosystem functions. Peatland plant community structure is predicted to change under future climate change, making the quantification of the direction and magnitude of this change a research priority. We subjected intact, replicated vegetated poor fen peat monoliths to elevated temperatures, increased atmospheric carbon dioxide (CO2 ), and two water table levels in a factorial design to determine the individual and synergistic effects of climate change factors on the poor fen plant community composition. We identify three indicators of a regime shift occurring in our experimental poor fen system under climate change: nonlinear decline of Sphagnum at temperatures 8 °C above ambient conditions, concomitant increases in Carex spp. at temperatures 4 °C above ambient conditions suggesting a weakening of Sphagnum feedbacks on peat accumulation, and increased variance of the plant community composition and pore water pH through time. A temperature increase of +4 °C appeared to be a threshold for increased vascular plant abundance; however the magnitude of change was species dependent. Elevated temperature combined with elevated CO2 had a synergistic effect on large graminoid species abundance, with a 15 times increase as compared to control conditions. Community analyses suggested that the balance between dominant plant species was tipped from Sphagnum to a graminoid-dominated system by the combination of climate change factors. Our findings indicate that changes in peatland plant community composition are likely under future climate change conditions, with a demonstrated shift toward a dominance of graminoid species in poor fens.
authors: Department of Biology, The University of Western Ontario, London, Ontario, N6A 5B7, Canada.
authors: Catherine M
authors: CM
authors: Dieleman
authors: Brian A
authors: BA
authors: Branfireun
authors: James W
authors: JW
authors: McLaughlin
authors: Zoë
authors: Z
authors: Lindo
mesh_terms: D000704:Analysis of Variance; D044822:Biodiversity; D002245:Carbon Dioxide / Q000378:metabolism; D057231:Climate Change; D017753:Ecosystem; D060587:Groundwater; D006863:Hydrogen-Ion Concentration; D008954:Models, Biological; D013045:Species Specificity; D044003:Sphagnopsida / Q000502:physiology*; D013696:Temperature
chemical_list: D002245:Carbon Dioxide
keywords: Carex; Sphagnum; carbon dioxide; climate change; peatland; poor fen; temperature; water table