Graduate Students

KATIE PAGNUCCO
Predicting the impacts of nonindigenous freshwater fishes.

My doctoral research aims to identify predictable patterns of impact involving non-native fishes in freshwater aquatic communities, with emphasis on the round goby as a model invader. Previous work by our lab (by R. Kipp, 2010) found evidence that the round goby enhances benthic algal biomass by substantially reducing invertebrate grazer populations at some sites in the St. Lawrence River, but not at others. Understanding the circumstances in which round gobies can trigger impacts that cascade through food webs is necessary in order to forecast impacts at sites prior to invasion. I am exploring goby-mediated trophic cascades through field experiments and multi-site surveys. I am also using meta-analyses to link variation in the impacts of introduced fishes in general to biotic and abiotic characteristics of recipient communities. Visit my website.

JOSIE IACARELLA
Predicting the impacts of aquatic invasive species from their organismal traits and functional responses.

I am generally interested in how an organism’s functional characteristics and the context of its environment affect its success and biotic interactions. Context-dependency is an important determinant of an invasive species’ impacts and may be used to predict the potential impacts of invasives in habitats that are at-risk for invasion. Previous work in our lab (by Åsa Kestrup) found that the direction of intraguild predation in amphipods changed depending on the conductivity of water; her research exemplified how an invasive species may have different impacts under different environmental conditions. My doctoral research will expand on this by analyzing how functional traits such as functional response, aggression, and physiological tolerance affect the impact of important aquatic invasive species (eg. bloody-red mysid shrimp and round goby). I will compare functional traits between invasive species and taxonomically related natives with known impacts, and between invasive species populations that have been established for different lengths of time.

ROWSHYRA CASTANEDA
Factors affecting the distribution, abundance and condition of an invasive freshwater bivalve in a thermal plume.

My research examines the distribution, abundance and condition of the Asian clam Corbicula fluminea in the discharge plume of a nuclear power plant (Gentilly-2) in the St-Lawrence River. The clam was discovered in the river in 2009 by Dr. Anouk Simard and her team at the Quebec Ministère des Ressources naturelles et de la Faune. The Gentilly site is the most northern limit reported for this warmwater species, which is considered to be one of the most invasive freshwater molluscs in the world.  By examining its population structure across the thermal gradient and comparing it to other populations worldwide, I hope to gain insight into the potential future distribution of Corbicula in the river as water temperatures continue to rise with climate change.

After having recently completed my MSc, I am currently working as a research assistant in the Ricciardi Lab.

KAYLA HAMELIN
Effects of thermal effluent on the diversity and distribution of benthic invertebrates in the St. Lawrence River.

I am broadly interested in the effects of abiotic variables on the distribution and community dynamics of aquatic organisms. I am currently studying the effect of thermal effluent from a nuclear power plant (Gentilly-2) on the benthic invertebrate communities of the St. Lawrence River. Specifically, my MSc research will compare the taxonomic diversity of the community within the thermal plume to that in the surrounding area in space (along the thermal gradient) and time (several years of data). Although this is the site of several species invasions, I will focus on impacts of temperature on the native community. Not only will this work provide insight into the effect of thermal pollution on aquatic communities, but this system acts as a "living laboratory" for evaluating the potential future effects of global warming on the St. Lawrence biota.

JORDAN OUELLETTE-PLANTE
Growth and filtration activity of invasive mussels.

My MSc research focuses on two invasive bivalves: the zebra mussel (Dreissena polymorpha) and the quagga mussel (D. bugensis). In comparison with the Great Lakes, which was invaded by these two species in the 1980s, their ecology in large rivers received relatively little attention - particularly how inorganic suspended sediment loads affects their growth and filtration. The St. Lawrence River is one of the few rivers in North America that contains both dreissenid species. Such a large system provides opportunities to study spatial and temporal variations along the river bed, which in turn will provide information on the shifting mosaic of abiotic and biotic conditions that form local habitats. This environmental heterogeneity provides a platform for comparing dreissenid tolerance to suspended sediments and temperature regimes. These data will improve our understanding of the underlying patterns of distribution and abundance of these mussels. Mussel filtration rate is one of the most important measures of ecological impact on invaded communities and thus will be the cornerstone of my project.  In addition to environmental variability, I will be examining the allometric relationships of shells and soft tissues and whether these variables are related to filtration rates.

AHDIA HASSAN
Correlates of ecological and economic impact for translocated nonindigenous species.

My MSc thesis explores correlates of impact for introduced animals. Extending across multiple taxa, I will evaluate negative impacts of established non-native species at population- and community-level scales. In addition to ecological impact, I am also interested in economic impact resulting from the establishment of exotics. While much of the literature on impact in the field of invasive species biology is anecdotal, recent studies have proposed hypotheses which may aid in predicting the magnitude of impact an invader will cause; these hypotheses, which remain largely untested, consider traits of the invader, biotic and abiotic characteristics of the recipient community, and introduction effort. Using existing global datasets on terrestrial mammals, herpetofauna, avifauna, and freshwater molluscs, my interest is to test these hypotheses and identify factors correlated with impact. Once identified, such traits may help predict the impact of newly established/potential invaders.

EMILIJA CVETANOVSKA
Changes to an invasive bivalve population following the removal of an artificial thermal plume in the St. Lawrence River.

My M.Sc. research will examine changes to the St. Lawrence River benthic community following the closure of the Gentilly-2 nuclear power plant. The power plant has been releasing a warm water plume that has created an artificial habitat for the northern-most established population of the invasive Asian clam, Corbicula fluminea. This species is typically found in warmer climates and is believed to limited by a survival threshold temperature of 2°C.  Using field surveys and temperature tolerance experiments in the lab, I will investigate the over-winter survival of the St. Lawrence population of C. fluminea. By examining the condition and abundance of the population after a temperate winter, I hope to gain insight into the adaptive characteristics of this species. The potential adaptation of C. fluminea to low temperatures has serious implications for lakes and rivers in Canada.