Climate change drives a shift in peatland ecosystem plant community: implications for ecosystem function and stability

Glob Chang Biol. 2015 Jan;21(1):388-95. doi: 10.1111/gcb.12643. Epub 2014 Jun 23.

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.

Keywords: Carex; Sphagnum; carbon dioxide; climate change; peatland; poor fen; temperature; water table.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Analysis of Variance
  • Biodiversity*
  • Carbon Dioxide / metabolism
  • Climate Change*
  • Ecosystem*
  • Groundwater
  • Hydrogen-Ion Concentration
  • Models, Biological*
  • Species Specificity
  • Sphagnopsida / physiology*
  • Temperature

Substances

  • Carbon Dioxide