EXTINCTION OR EVOLUTION OF POPULATIONS AFTER A CHANGE IN THE ENVIRONMENT
The current rates of environmental change experienced by animal populations are higher than have been experienced over much of fossil record. My laboratory investigates the factors that determine whether a population will adapt to a change in the environment without going extinct.
Current Project 1: Invasion Biology: Comparing Scales of Local Genetic Adaptation to Exotic Predators by Prey with High and Low Dispersal Potential (with Karen Rickards and David Hunt)
Environmental change caused by human activities is allowing exotic predators and competitors to extend their geographical ranges into Canada. For example, increased sea surface temperatures during the 1997/98 El Niño allowed larvae of the subtropical lined shore crab to metamorphose on western Canadian shores and prey on four closely-related species of indigenous snails. These temperate snail species have shells that are vulnerable to the specialized shell-breaking appendages of predators from more tropical regions. Consequently, climate-driven range expansion of subtropical predator species may result in range contraction by temperate prey species unless they can quickly evolve thicker armour. This is an excellent system for studying the effect of prey migration on adaptation to subtropical predators. These four intertidal gastropods are ecologically similar but differ considerably in their dispersal potential: two species have a long-lived free-swimming larval stage and two species have lost the free-swimming larval stage and as a result disperse only by crawling. My long term research program assesses the importance of rapid evolution in preventing populations from going extinct after changes in the environment. During this grant cycle, I will test the hypothesis that prey species with high dispersal can only adapt to predatory crabs that invade their entire geographic range. Consequently I predict that rapid evolution may be more important in preventing poorly-dispersing species from going extinct as these have lifetime dispersal distances of a few metres. I have three short-term objectives that will all compare Littorina species with and without a free-swimming larval stage: 1) To compare the minimum spatial scale of genetic adaptation to predators, 2) To compare the length of coastline occupied by a single population, and 3) To compare the amount of phenotypic plasticity in adaptive complex traits known to form clines. I plan to parameterize an extension of our individual-based quantitative genetic model which could also be useful for understanding the effect of dispersal on adaptive population differentiation in other systems. (funded by NSERC Discovery grants Ph.D. position available ).
Past Project 2: Integrating ecological research and hatchery operations for the restoration of the threatened northern abalone Haliotis kamtschatkana (M.Sc. graduates: Matt Lemay and Kaitlyn Read)
My laboratory's part in this research has been to improve outplanting strategies for rebuilding wild Northern abalone populations. Kaitlyn has evaluated the success of past outplanting efforts via non-lethal genetic identification of outplanted individuals in the wild using microsatellites protocols developed by Matt Lemay. Her genotyping suggests that past larval outplanting has been successful. Her work has also shown the importance of habitat-modification and predator control in facilitating the survival of outplanted hatchery-raised animals in the wild. By using a combination of laboratory and field techniques, we have gained important insights into the biology of this species. (past Funding: NSERC Strategic grant: PI: Dr. Louis Gosselin (Thompson Rivers University); co-investigators: Dr. Chris Harley (UBC) and myself for K. Read. Also past AQUANET (PI myself for Matt Lemay).
Aquaculture now produces all the Atlantic salmon consumed by Canadians and a significant amount for export. However, disease is a major constraint affecting the sustainability and profitability of this industry. Foremost is disease 