COS 155-3 - Predicting the invasion success of zebra and quagga mussels

Wednesday, August 17, 2022

10:30 AM – 10:45 AM EDT

Location: 516D

Presenting Author(s)

SB

Steven F. Brownlee

PhD candidate
Simon Fraser University
Burnaby, British Columbia, Canada

Coauthor(s)

IC

Isabelle M. Côté, PhD

Professor
Simon Fraser University - Burnaby, BC
Burnaby, British Columbia, Canada
JM

Jonathan Moore

Simon Fraser University, British Columbia, Canada

Background/Question/Methods

Zebra and quagga mussels (Dreissena polymorpha and D. Rostriformis bugensis) are a pressing threat to freshwater biodiversity in North America. Since 1989, these eastern European invaders have spread from the Great Lakes across the continent via boats and downstream dispersal. Previous efforts to model the susceptibility of freshwater systems to dreissenid mussel establishment have used primarily correlative approaches to predict habitat suitability at a continental scale, but these models are limited in their ability to predict the susceptibility of individual water bodies to invasion. To fill this gap, we used a systematic literature review and meta-analysis to identify the variables most likely to contribute to invasion success and failure in dreissenid mussels, and extracted response curves for these variables to build a mechanistic niche model for these invaders. This niche model evaluates the fitness of juvenile planktonic and adult mussels separately over time, given real seasonal temperature and environmental data, giving a clear temporal picture of how fitness changes over time, which should translate into the likelihood of a successful introduction event – the higher the mussel fitness predicted by the model, the higher the likelihood an introduction would succeed.

Results/Conclusions

The literature review and meta-analysis identified five key variables important for constraining dreissenid mussel success: calcium availability, salinity, temperature, substrate type and food availability. Response curves of juvenile planktonic and, separately, adult mussels to each of these variables were compiled, and then used to build the framework for the niche model. We applied the model to BC’s Okanagan Lake, which is not yet invaded by dreissenid mussels, and found that it is highly suitable for mussel establishment as fitness scores remained high throughout the year in several parts of the lake. These results represent an important step forward in our ability to understand the constraints on zebra and quagga mussel invasion success. Moreover, this methodology can be easily applied to other invaders as part of an expanding toolkit for managers working to mitigate the threat of invasive species.