Grant: Alliance Grants

The spiny water flea (Bythotrephes cederströmii) is a predatory zooplankton species native to Eurasia that has successfully established itself in the North American Great Lakes and become invasive. This crustacean has caused severe damage to lake ecosystems and aquatic food webs, affecting lake functioning and even human recreational activities. Until recently, more northern regions appeared to offer less suitable lake conditions for this invasive species. In 2018, however, the spiny water flea was discovered in Lake Témiscamingue by the Quebec's early-detection program; thus, this invasive species had now reached the doorstep of the boreal region. It remains uncertain what this establishment in northern lakes will imply and how extensive the spread of Bythotrephes will be across the boreal region. This project aims to better understand the invasion dynamics and consequences of Bythotrephes for Canadian northern lake ecosystems. First, we will develop a model to predict the spread of Bythotrephes and create a map of the most vulnerable lakes of eastern Canada, including boreal lakes. Data related to human activities around the lakes will be gathered via remote sensing imagery, municipal and ministerial data sets, and community-based data. Second, we will compare changes to the lake ecosystems caused by the invasion and determine Bythotrephes' habitat preferences along a temperate-boreal gradient of lakes. This sampling will include 15 Bythotrephes-invaded lakes and 15 non-invaded lakes. Zooplankton, including Bythotrephes, and zooplanktivorous fish communities will be sampled from each lake. Also, food web structure and complexity will be assessed with stable isotope analyses. Third, we will determine the habitat and food resources variables that influence the seasonal, spatial, and life cycle variability of Bythotrephes population in Lake Témiscamingue. We will conduct bi-weekly sampling in Lake Témiscamingue to assess zooplankton community composition and Bythotrephes habitat. This project will allow us to better understand the ongoing spread of Bythotrephes and its effect on northern lake food webs to improve forecasting of possible species losses.