Continued economic and population growth in the Northern Great Plains (NGP) will depend in large part on the availability and quality of water. Tools are required to monitor and assess the sustainable use of the province’s surface water resources. Currently water quality in theCanadian Northern Great Plains is assessed solely using water chemistry analysis which provides only a snapshot of condition in time and does not evaluate the health of the aquatic ecosystem. Evaluation of aquatic ecosystem health is important both because the ecosystem acts as a biofilter to purify water, and because declines in ecosystem health signal the presence of pollutants. Establishment of site-specific aquatic ecosystem objectives using healthy (reference) sites would complement surface water quality objectives based on chemistry and enable results-based management for water quantity, quality, and biodiversity.

However, the prerequisite for the tools to measure ecosystem health at a specific site is a sound understanding of the benthic macroinvertebrate community’s structure, how it is structured by its environment, and then how the community changes when human activities impact its physical environment ¹. These principles underlying an ecosystem health assessment are fundamentally under-studied, and their scientific understanding is insufficient to merely expand existing monitoring programs to include the Northern Great Plains. Benthic macroinvertebrate communities change (species composition, abundance of individuals, and species diversity) depending on the type and amount of pollution present in the system ². Measurable, predictable change enables development of ecological health indices. Other jurisdictions (e.g., United States, Britain, European Union, Australia) have developed macroinvertebrate aquatic health measures that together with water chemistry, are used to establish and monitor surface water quality objectives. However, macroinvertebrate measures for the Northern Great Plains of North American have been more difficult to develop because the natural extremes (winter, drought, landscape disturbance, high nutrient and productivity) of this region result in a community characterized by taxa already more tolerant to pollution than those found elsewhere in North America. Therefore macroinvertebrates in the NGP may be insensitive to pollution relative to other regions. As such, the feasibility of an aquatic health measure using NGP macroinvertebrates requires investigation before application of existing tools from other jurisdictions.

The main objective of Iain’s work is to build a benthic macroinvertebrate community based biomonitoring tool for the Northern Great Plains. To begin with, his study will characterize the physiochemical and hydrological characteristics of Northern Great Plains streams. This will set the background of how rivers on the NGP are unique relative to classic understandings of the River Continuum Concept, and how broadly applicable the extent of these characteristics are across other prairie ecosystems of the world. Second, he will associate these underlying physical characteristics to the benthic communities occurring throughout the NGP, to understand relationships between benthic macroinvertebrates and their environment. This work will discern which physical characteristics explain the most variation in benthic communities and define biological groupings, or Benthic Ecoregions of Saskatchewan. From this understanding, his next step will focus on assessing how the benthic community changes from its natural composition in the presence of common anthropogenic perturbation. Specifically, how the benthic macroinvertebrate community is affected by increasing land-use, and landscape disturbance. Responses of benthic macroinverterbate communities to particular land-use (e.g., crop, urban waste-water effluent), landscape disturbances (e.g., wetland drainage), and stressors (e.g., sediment deposition, turbidity, temperature) will all be adapted into metrics of impact forensically indicative of each perturbation. Next, his thesis will adapt these understandings of underpinning environmental-community relationships and disturbance metrics to a bioassessment tool able to statistically evaluate benthic community-based ecosystem health or impairment relative to reference condition. From this stage, Iain will evaluate the relative usefulness of the major ecosystem health monitoring tools applied across North America in his last stage for their ability to detect impairment, ease of execution, diagnostic capability, and amount of error committed. Iain will assign and refine the method most appropriate for the NGP, and how it can be delivered as a tool to report ecosystem health.

References

¹ Bowman, M.F., and K.M.Somers. 2005. Considerations when using the reference condition approach for bioassessment of freshwater. Water Quality Research Journal of Canada. 40(3): 347-360.

² Rosenberg, D.M., and V.H. Resh (editors). 1993. Freshwater Biomonitoring and Benthic Macroinvertebrates. Chapman and Hall, New York, USA.