Thesis Research


Supervisor: Dr. Frédéric Guichard

Many organisms have two distinct phases of movement: a sedentary or slow-moving adult stage (such as trees or mussel beds) and a generally short-lived and fast-moving juvenile stage (e.g. seeds or pelagic larvae). While each organism may spend the bulk of its life in its adult stage, the mechanisms that drive movement of the juvenile stage play a vital role in the survival of the organism, as the juvenile's movement determines the conditions the adult will face.

One particular mechanism that may play an important role in population dynamics is packet-driven (or clustered) dispersal; this is where individuals (of one or more species) move together in a spatially discrete group, and settle simultaneously in some location. This may be driven by physical forces, such as large marine eddies driving larvae together, biological factors such as seeds in a single seed head moving together or seeds being eaten and defecated by an animal, or by organism behaviour, as with schooling or herding animals. The result is that individuals end up arriving at their final habitat in clusters, which means individuals will typically face stronger density-dependent interactions with one another than they would under un-clustered settlement.

My research focuses on understanding packet-driven dispersal in marine invertebrates. There's several questions Iım trying to answer: 1) How can we detect packet-transport in larval settlement, and determine what mechanisms are causing it? 2) How does clustering in the water column affect the behaviour of dispersing larvae? 3) What long-term impact does packet-driven transport have on population dynamics, and how should this impact vary with the spatial scale of the packets and the spatial scale a given species interacts at? To understand these questions, I work with theoretical population and behaviour models, behavioural experiments and statistical analysis of larval distribution and settlement data.

Other Research


I am interested in a broad range of topics in movement ecology, including estimating how movement behaviour changes with habitat, modelling time-varying connectivity between landscapes, and understanding the links between movement behaviour and ecological resilience of communities (that is, to what degree a community's dynamics will change under external perturbations).

I receive research and travel funding from NSERC, the Canadian Healthy Oceans Network (CHONe), Québec Océan, and the Center for Applied Mathematics in Biology and Medicine (CAMBAM).

Education


B.Sc. Biology and Economics, University of Saskatchewan, 2003 - 2008
Ph. D. Candidate in biology, McGill University, 2009 to present.

Publications


Reyna-Hurtado, R., Chapman, C.A., Calme, S., and Pedersen, E.J. (2012). Searching in heterogeneous and limiting environments: Foraging strategies in a social ungulate, the white-lipped pecccary (Tayassu pecari). Mammology 93, 124-133.

Johnstone, J.F., McIntire, E.J.B., Pedersen, E.J., King, G., and Pisaric, M.J.F. (2010). A sensitive slope: Estimating landscape patterns of forest resilience in a changing climate. Ecosphere 1, art14.

Sheoran, I.S., Pedersen, E.J., Ross, A.R.., and Sawhney, V.K. (2009). Dynamics of protein expression during pollen germination in canola (Brassica napus). Planta 230, 779-793.

Last update: July 31, 2012
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