We are interested in a variety of issues pertaining to invasive species, from analyses of pathways and vectors of introduction and including risk assessment, to genetic characterization and evolution, to impacts and mitigation.
1) The air mass above the Arctic has warmed, opening opportunities for both natural dispersal and human-mediated spread of nonindigenous species. We are characterizing different pathways (hull fouling, ballast water) as mechanisms are dispersal vectors of nonindigenous species to this region.
2) Invasion risk may be related both to the number of introduction events and propagule per event. We are characterizing multi-species invasion vectors through analyses of species rank abundance distributions. These distributions may be very informative with respect to invasion risk, as they use information both on propagule pressure and colonization pressure. We can also explore the effects of time and distance and of ballast water exchange by conducting time series or before:after experiments.
3) Detecting nonindigenous species soon after they arrive is imperative if we seek to identify and eradicate invasive species. Our lab – as part of the Canadian Aquatic Invasive Species Network – has collected samples from 16 ports in 4 regions of Canada to determine the species complement using both traditional taxonomy as well as next generation sequencing (NGS). We have found that NGS may allow detection at animal abundances three orders of magnitude lower than traditional sampling and microscope-based taxonomy, however artifacts are common in NGS datasets and we must devise methods for eliminating them. We are also determining the limits of traditional taxonomy to determine when assessments may miss species that are present at very low abundance.
4) We have worked with the shipping industry to determine the efficacy of ballast water exchange, as well as experimentally test different combinations of treatment. This work may become highly relevant after the IMO D-2 performance standards for ballast water come into place globally.
5) We are interested in characterizing risk to Chinese ports of discharged ballast water. China has 13 of the world’s 20 largest ports, yet assessments of invasion risk have never been conducted. In addition, climate change has resulted in drought in Northern China, a solution to which was creation of water diversions from southern China. We are investigating how these diversions may help spread mass invaders like the golden mussel Limnoperna fortunei.