Evaluating Foliar Nutrient Concentrations As an Indicator of Belowground Function in Reclaimed Soils of the Athabasca Oil Sands Region.

Environmental indicators are meant to represent a simplified version of complex processes occurring in the ecosystem. However, a common mistake with the use of indicators is that processes are often oversimplified, or methods that may be appropriate for one ecosystem are applied to another where they may not be as able to accurately represent the complex processes they are meant to demonstrate. Official recommendations for Alberta’s Athabasca Oil Sands Region suggest that the monitoring of only selected individual nutrient concentrations in foliar tissue is sufficient to represent overall nutrient cycling on a site. We found that foliar nutrient concentrations were not useful indicators of nutrient cycling in natural and reclaimed sites and that they do not correlate to belowground nutrient concentrations; neither those nutrients readily available for uptake from the soil solution, nor nutrients bound to the soil particles themselves. Our investigation found that this is the case in both natural sites and sites undergoing reclamation. Different reclamation soils and treatments had limited effect on the overall accuracy of foliar nutrient concentrations as an indicator.

Univariate analysis (ANOVA) of the concentrations of individual nutrients suggested that there was a convergence of nutrient concentrations from the total soil nutrient pool to the foliar nutrient pool across the different soil treatments. However, multivariate analysis (Non-metric multi-dimensional scaling) suggested that the relationship between the different soil treatments remains relatively consistent through all three nutrient pools. Multivariate analyses are better able to capture the complexities of the overall nutrient pool and it is our hope that the more widespread use of multivariate analysis will be adopted by reclamation practitioners to assist in determining reclamation success and ecosystem functional similarity.