Potential influence of nutrient availability along a hillslope: Peatland gradient on aspen recovery following fire
Depante, M., R.M. Petrone, K.J. Devito, N. Kettridge, M.L. Macrae1, C. Mendoza and J.M. Waddington. 2018.
Abstract
The Boreal Plains (BP) of Western Canada have been exposed to increasing disturbance by wild-
fire and host a mixture of upland-wetland-pond complexes with substantial quantities of trembling
aspen (Populus tremuloides Michx.) throughout the terrestrial areas. The ability of these tree
species to regenerate within both upland and wetland areas of the BP following wildfire is unclear.
The purpose of this study was to investigate the influence of fire on nutrient dynamics in soil and
water in peatlands and forested landscapes in the BP and relate this to aspen regeneration. Nutrient
concentrations, nutrient supply rates, and net nutrient mineralization rates were determined in
burned and unburned sections of a peatland and forest and compared with the regeneration of
aspen. NO3+, NH4 , and P varied spatially throughout the landscape, and differences were
observed between peatland and upland areas. In general, differences in nutrient dynamics were not
observed between burned and unburned areas, with the exception of P. Nutrient and growth data
suggest that aspen do not require nutrient-rich conditions for regeneration and instead relied on
forest litter to satisfy nutrient demands. Although the peatlands contained high nutrients, aspen did
not flourish in the combination of anoxic and aerobic organic-rich soils present in this area.
Although aspen may use peat water and nutrients through their rooting zones, peatlands are
unsuitable for aspen re-establishment in the long-term. However, the combination of abundant
nutrients in surface mineral soils in peat margins may indicate the vulnerability of margins to
upland transformations in later successional stages.
