Barbara J. Nicholson and Suzanne E. Bayley, and Markus N. Thormann
Proceedings of the 14th International Peat Congress
drawdown, ponds, transitional, vegetation
Nicholson et al 2012: Vegetation Cycles in Boreal Peatland Ponds: Effects of Drought and Flooding
Theme I. Inventory, stratigraphy and conservation of mires and peatlands
The Boreal plain of Canada contains millions of small ponds surrounded by peatlands. Little is known about their response to variability in precipitation. We examined the response of Boreal peatland ponds in Utikuma, Alberta, to drawdown and reflooding. Drawdown produced concentric vegetation patterns that were transitional between herbaceous marshes, and bryophyte dominated fens. During wet years floating mats developed within the transitional vegetation. Areas topographically higher than the mats became wetter than the mats. Oscillations in water levels thus produced two unique features: transitional fen/marsh vegetation that has a blend of species indicative of both hydrological stability and instability, and a ring of wetter vegetation upslope of the transitional fen/marsh community.