Assessing Long-Term Ecological Changes in Lake Scugog (Southern Ontario, Canada) from ~1700 to 2019 Using Cladocera (Branchipoda, Crustacea) Subfossil Remains as Paleoecological Indicators

Lake Scugog is a shallow impoundment located in southern Ontario that is encountering several anthropogenic stressors, such as the introduction of invasive species, eutrophication, periodic algal blooms, and climate change. This thesis used a paleolimnological approach to assess the long-term (~200 years) ecological changes in the west and east arms of Lake Scugog using Cladocera (crustacean zooplankton, Class Branchiopoda) remains as bioindicators.

Bosmina and C. brevilabris were the dominant cladocerans in Lake Scugog throughout the last several hundred years. Measured Bosmina body sizes were small, indicating high fish planktivory pressure on Bosmina. The changes in subfossil Cladocera and Bosmina in sediments suggest that the stress levels associated with eutrophication, climate change and invasive species have not been large enough to significantly alter predation levels or this part of the zooplankton community in Lake Scugog.