Pacific Institute for the Mathematical Sciences - PIMS

Prediction of range expansion of nonindigenous species is important, as
it is often easier to prevent invasions than to mitigate impacts once
invasions have occurred. A combination of models for propagule pressure
(gravity models) and habitat matching based on lake chemistry and fish
communities allow for refined predictions of where species may be
expected to disperse and establish. We compare dispersal patterns and
mechanisms of the spiny waterflea and the zebra mussel in inland
Ontario lakes. We surveyed recreationalists regarding the movement of
trailered boats to model vector traffic among lakes, and used this
measure of propagule pressure as the first input into a logistic model.
Both species are transported overland by mechanisms associated with
boating, though differences in dispersal may be influenced by
differences in life-history traits, which, in turn, influence the
relative importance of different mechanisms. For example, spiny
waterflea resting eggs may be transported long-distance on contaminated
fishing line, whereas zebra mussel adults may attach to macrophytes
entangled on boat trailers. Simulations will be highlighted that
illustrate predicted differences in spread based upon dispersal vectors
and environmental tolerances.

Jim Muirhead is with the Great Lakes Institute for Environmental Research, University of Windsor.