Graduate Students

VICTORIA VAN MIERLO
Environmental mediation of the establishment and impact of invasive crayfishes.

My PhD research examines environmental factors that influence the abundance and impact of aquatic invasive species, using crayfish as a model organism. Overall, I am applying hypotheses and concepts in invasion ecology to understand context dependencies, and I am working with two invasive crayfishes. My specific objectives are to 1) predict the colonization and potential impacts of the marbled crayfish in the Great Lakes basin, and 2) relate the occurrence and local abundance of the spinycheek crayfish to environmental variables in the upper St. Lawrence River. Previously, for my MSc I worked on occupancy models for the virile crayfish invading the North Saskatchewan River basin and the potential interactions between invasive crayfish and native fishes using stable isotopes.

IVANA KOMENDIC
Factors affecting the impact of invasive mussels in spatially heterogeneous environments.

For my Ph.D. research, I am investigating zebra mussel invasions of two Quebec lakes, L. Memphremagog and L. Témiscouata, both of which are in early to mid stages of invasion and present unique environmental conditions (e.g., suboptimal calcium concentrations). I am testing empirical models of population abundance as well as the ecological impacts of zebra mussels in these lakes. More specifically I am examining impacts on native unionid mussels. Lastly, I will conduct a risk assessment of zebra mussel colonization and impact potential in lakes.

EMMA SCHUBERT
Direct and indirect effects of goldfish invasions on pond ecosystems.

For my MSc research, I will be focusing on the invasive common goldfish (Carassius auratus) and its effects on turbidity, temperature, and benthic algal growth in urban and natural pond environments. Due to their benthic foraging behaviour, goldfish are known to increase the turbidity (suspended sediments) of aquatic environments. This has negative effects on the local ecosystem. I will be conducting an outdoor mesocosm study at the Gault Nature Reserve using a variety of densities of goldfish to determine the possible effects of goldfish density on three pond ecosystem characteristics. This research will explore the possible future impacts of goldfish on freshwater ecosystems at risk of invasion, as well as quantify their current impacts on invaded ponds.

TY COLVIN
Temporal changes in biodiversity of St. Lawrence River benthic invertebrate communities.

For my Ph.D. research, I am investigating patterns of benthic invertebrate biodiversity change in the St. Lawrence River over the past 40 years and relating spatiotemporal changes in benthic communities to different species invasions and climate warming thresholds. To this end, I am comparing modern benthic communities along the river to long-term historical community data and relating biodiversity change to the establishment and spread of specific invasive species. I am also conducting field experiments to test hypotheses on the role of different invaders in influencing benthic communities, particularly invasive gobiid fishes, dreissenid mussels, and their interactions.

KATE STOREY
Comparing the functional response of wild and cultivated goldfish populations.

My research focuses on the common goldfish (Carassius auratus), a longstanding member of the aquarium trade that has made its way into native waterways across Canada. I aim to determine the relative risks of impact of three goldfish populations; those collected from wild ponds, those collected from urban ponds, and those sourced from a pet store. I will examine the feeding behaviour of these populations through functional response experiments using complex habitat and live prey to determine the predation and cognitive ability of these populations and whether it has changed under wild stressors. These experiments will be run at current mean summer temperature as well as predicted mean maximum summer temperature of the Great Lakes region, to assess different populations adaptations to seasonality and future impact under climate change.

BRIELLE COMARTIN
Impacts of zebra mussel invasion on native freshwater mussels in a Quebec lake.

With collaborators from the Quebec Ministère des Forêts, de la Faune et des Parcs, I investigated the impacts of zebra mussel (Dreissena polymorpha) invasion on native unionid mussels in Lake Memphrémagog, southeastern Québec. For my MSc research, I examined the role of biofouling by zebra mussels on unionids in Memphrémagog in population collapse, and whether these events are predictable. This lake allowed me to study the effects of zebra mussels under relatively low calcium concentrations (<20mg/L), which can limit zebra mussel abundance, and compare these effects to those documented in calcium-rich environments. The results can be used to develop enhanced risk assessment tools for predicting zebra mussel impacts on native biodiversity. After having completed my MSc, I am now lab manager for the Ricciardi Lab.