Lake Manitoba and its Watershed: Knowledge Gaps & Next Steps

Abstract

Lake Manitoba is a large, shallow prairie lake located in central Manitoba. The lake and watershed are subject to numerous environmental pressures including climate change, land use change, and regulation of water levels, particularly during the operation of the Portage Diversion which diverts water from the Assiniboine River into Lake Manitoba. There are substantial gaps in our scientific knowledge about the ecology, limnology, and hydrology of Lake Manitoba, which limit our ability to make informed management decisions. A science workshop was convened at the University of Winnipeg in December 2015 to summarize the state of knowledge around water quality and ecosystem functioning in Lake Manitoba and its watershed, identify key knowledge gaps, and develop ways to address these gaps. The workshop was attended by 34 participants from universities, government agencies, and non-governmental organizations, all of whom had particular expertise in one of four theme areas: Water Levels & Regulation; Watershed Management & Landscape Processes; Water Quality; and Ecology & Wetlands. This report summarizes the findings and recommendations of the workshop, and can be used to help guide research priorities into the future. While specific, detailed recommendations were made in each theme area, two major recommendations emerged across all themes. The first recommendation is the existence of critical data gaps which must be filled before progress can be made on understanding ecosystem functioning. These gaps include physical data (e.g. bathymetric, meteorological and LiDAR data), water quality data (e.g. off-shore water chemistry, tributary nutrient loading), and ecological data (e.g. algal community composition, zooplankton characterization, macroinvertebrates population estimates). Furthermore, we do not understand the extent of spatial and temporal heterogeneity in the Lake Manitoba system. Much of the monitoring that does take place occurs along the edges of the lake during the open water season, resulting in large gaps in our understanding of processes occurring in the middle of the lake or during the winter. Without filling these critical data gaps, our scientific understanding of the system is incomplete and we are limited in our ability to make recommendations to resource managers and stakeholders. The second general recommendation that emerged is the need to coordinate research activities across disciplines and agencies. Lake Manitoba and its watershed are complex ecosystems which are connected to the landscape and other waterbodies, including Lakes Winnipeg and Winnipegosis. To this end, we propose establishing a Manitoba Great Lakes Research Consortium to coordinate and disseminate research across Manitoba’s Great Lakes. Such an organization could also facilitate a repository to make data collected from Lake Manitoba and connected ecosystems accessible to researchers and stakeholders. While there are major gaps in our understanding of ecosystem functions in Lake Manitoba and its watershed, this report provides a way forward. For the gaps that were identified as the most pressing, workshop participants outlined plans of action to address these gaps, including identifying collaborators, potential sources of funding, and timelines to achieve these goals. These next steps will be useful to researchers, government agencies, and non-governmental organizations as they move forward to address the issues facing Lake Manitoba.