Monitoring and research projects through the LSPP have been critical to help understand important issues, such as the changes due to invasive species and climate change. The long term trends and research findings help inform actions to protect the lake and its watershed, and are reported in the Lake Simcoe Minister’s Annual Reports.

Stresses from human activity continue to have a significant effect on the ecological health of Lake Simcoe and its watershed. There has been a minimal rate of loss of woodland and wetland areas, and more than half of the Lake Simcoe watershed is used for agriculture and urban areas. Future monitoring and research are required on the watershed at both the landscape- and site-level to build on the baseline analysis of high quality natural cover. This will ensure that this indicator can be tracked over time to help maintain, protect and enhance the important functions and biodiversity of natural cover.

Extensive contaminant monitoring identified increases in total suspended solids in some tributaries, and increased chloride in most tributaries with signs of it negatively affecting tributary aquatic life (LSRCA 2024). Chloride concentration also continued to increase in the lake but it was not yet at levels that might affect aquatic life. Other contaminants such as microplastics, pharmaceuticals and personal care products, and PFAS were found to be below guideline levels.

Efforts to prevent new invaders to the lake and watershed, and, when possible, control and manage new and existing invaders, has continued. Unfortunately, species introduced prior to the LSPP have had significant effects. Dreissenid mussels in particular appear to have altered lake functioning. Additionally, global changes to both the timing and intensity of our climate continue to have a significant effect.

These complex changes also appear to be influencing lake processes. For example, phosphorus loading appears to now be strongly influenced by changes in seasonal air temperature and precipitation patterns. Thus, phosphorus loading has been high in years when flows are high. Conversely, concentrations of phosphorus and chlorophyll-a in the lake have declined and end of summer deepwater dissolved oxygen has increased overall, likely from the effects of invasive species and climate change. These effects have rippled through the lake food web with changes to abundances and community structure of the lower trophic communities including benthic invertebrates, phytoplankton and zooplankton that in turn could be affecting the fish.

Through monitoring programs and research in critical areas, understanding of the complex changes in Lake Simcoe continues to improve.  It is important to continue to study and monitor Lake Simcoe and its watershed to inform adaptive management to protect Lake Simcoe for generations to come.