Multiple Element Limitation Thermal Erosion Features

We calibrated the Multiple Element Limitation (MEL IVarc, Rastetter et al., 2013 and Pearce et al., in press) model to Alaskan arctic tundra to simulate recovery of thermal erosion features (TEFs) caused by permafrost thaw and mass wasting. The MEL model was calibrated to match annual C, N, P and water fluxes of tussock tundra on the North Slope of Alaska near Toolik Lake, AK (68° 38'N, 149° 43'W) (see Pearce, in press for details). The calibrated simulates acidic tussock tundra under 2000 climatic conditions, warming, warming and fertilization, fertilization, and decreased solar radiation reasonably well. In all TEF simulations we assumed that the slope failure caused by the disturbance had stabilized prior to the start of the simulation and that there was no ongoing downslope mass transfer. We cut initial biomass by 90% to reflect the loss of the majority of the standing biomass after a thermal erosion disturbance. We than ran several simulations with varying Phase I and Phase II SOM to reflect a range of possible post-disturbance conditions among and within TEFs. We also simulated conditions that result in a higher availability of nutrients than in the undisturbed tundra used for our calibration.