The Future of the Peatland Soils of Western Canada: Cumulative Effects of Natural and Anthropogenic Disturbance.

The future of the peatland soils of western Canada: cumulative effects of natural and anthropogenic disturbance

            Across the western boreal forest of Canada, peatlands occupy 365,160 km², or about 40% of the boreal landscape.  These peatlands store an estimated 42 Pg of carbon as peat and 6 Pg of carbon in living plant biomass.  Almost all of this large store of carbon has been accumulated over the past 6-7,000 years at long term rate of 19.4 g C/m²/yr.  This C stock represents approximately 2.1% of the worldÕs terrestrial C.  These peatlands and their extensive deposits of carbon were initiated almost entirely through paludification, a process in which disturbance is an important factor.  However current disturbances across the boreal forest have direct influences on peatland performance.  Here we evaluate changes in carbon sequestration due to a number of current disturbances, including direct and indirect effects of fire and changes in the fire regime, permafrost degradation, peat extraction, reservoirs, and oil sands mining. The cumulative effects of these natural and anthropogenic disturbances will substantially alter the C storage of the boreal forest and according to our estimates only an additional small change in area of disturbance will convert these northern organic soils to a net C source to the atmosphere.