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.

MADDIE PICARD
Context-dependent performance of a new invader, the tubenose goby.

My master’s research focuses on the impacts of the invasive tubenose goby (Proterorhinus semilunaris)across spatial and environmental gradients. Over the past decade, the tubenose goby has been slowly spreading in the St Lawrence River from the Great Lakes, where it was introduced circa 1990. This recent expansion will allow me to compare the per-capita effects of individuals at different times-since-invasion. Using in-lab functional response experiments, I will also compare the feeding efficiency of this species under different chemical and thermal conditions, to better predict its trophic impacts in the field.