Zooplankton communities are good indicators of potential impacts of Athabasca oil sands operations on downwind boreal lakes

We used zooplankton communities as indicators to evaluate the potential influence of acidifying–eutrophying emissions from the Athabasca oil sands region (AOSR) on 244 downwind lakes in northwest Saskatchewan. The impacts of regional environmental change on zooplankton communities are determined by responses of resident species to altered local environmental conditions as well as changes in composition due to dispersal processes. To test and quantify the relative importance of these individual processes, we conducted ordination analyses, spatial modeling, and variation partitioning. Local environmental factors were the dominant determinants of community structure, including two major environmental gradients susceptible to atmospheric emissions (i.e., acid–base status and productivity). Spatial structuring of these factors induced similar spatial structures in zooplankton distribution across the region. However, disentangling any impacts of the AOSR on these environment–spatial–species relationships from the underlying natural variability was precluded by unavailability of baseline data. Nevertheless, as our findings indicate that dispersal of zooplankton was not strongly limiting across this broad geographic region, zooplankton indicators can be crucial to detect future environmental changes in lakes across northwest Saskatchewan.