McGill University
Candidat M.Sc.
superviseur(e): Irene Gregory-Eaves
Beatrix Beisner
Zofia Taranu, Environment and Climate Change Canada
Début: 2022-09-01

Projet

Do critical transitions alter the network structure of zooplankton assemblages: a paleolimnological approach
With increasing human pressures, ecosystem resilience often erodes, making critical transitions more likely. We define a critical transition as a rapid change to an alternative stable state, with much difficulty returning to the prior ecosystem state. Examples include clear freshwater lakes transitioning into a turbid-state due to anthropogenic stressors. For this project, we will use paleolimnology to investigate whether subfossil cladoceran network structures differ between lakes with and without a critical transition. To identify such transitions, we will apply Online Dynamic Linear Models to times series of chlorophyll-a and its diagenetic products from cores collected by the LakePulse network, and test whether the dominant eigenvalue of the variance-covariance matrix of the models crosses the unit circle. We will then quantify how the network of subfossil cladoceran assemblages have changed over time to assess whether changes in connectedness and robustness are greater in lakes in which a critical transition has occurred.

Mots-clés

Critical transition, Regime shift, zooplankton, Network, community ecology, Paleolimnology, limnology