Can Spatial Patterns of Soil Respiration and Nutrient Availability Indicate Ecosystem Function in the Reclaimed Boreal Environment?.

Surface mining of oil sands in northern Alberta is a large scale disturbance with over 750 km² affected to date. Extraction companies are required by law to return the environment to ‘equivalent land capability', but this has proved challenging to quantify meaningfully and only one site has been certified as reclaimed. Restoring ecosystem function might be more realistic and may be quantifiable by examining spatial patterns of microbial and nutrient indices. In an ongoing study, soil respiration and plant available nutrient data was collected from 4 different sites and evaluated using spatial statistics. The reclamation treatments considered were peat mineral mix (PMM) and forest floor mineral mix (FFM) and these were compared to natural benchmarks including recovery from fire and clear cutting. We measured the CO₂ flux monthly during the growing season using a Li-Cor 8100A Soil CO₂ Flux system. Nutrient data was sampled for an 8 week period using Plant Root Simulator™ probes. The data indicated that there were differences in the pattern of soil respiration between different sites. Reclaimed sites seemed to show smaller scale spatial patterns than sites disturbed by clear cutting and forest fire. Apparently observed plant available nutrients (N, P, K, S) could not be linked directly to the pattern of soil respiration. This might be an indication that nutrient availability is not the main driver regulating biotic activity in the boreal zone. These interactions must be understood in order to evaluate the measurement of soil CO₂ flux as indicator for functionality of reclaimed sites in the boreal zone.