From Mussels to Crayfish and Gobies: Have the Great Lakes Experienced an “Invasional Meltdown?”

Approaching Beaver Island from air (Photo credit: Eric  Larson)

Guest post by Eric Larson, postdoctoral research associate, Shedd Aquarium

Not many people have likely heard of Beaver Island, a large, isolated island located far off shore at the northern end of Lake Michigan. Home to roughly 600 permanent residents and accessible only by ferry or small plane, Beaver Island is a well-kept secret of remote Great Lakes shores and dense forests. It is also home to Central Michigan University’s Biological Station (CMUBS), which has served students and researchers alike since 1959. This June, I made the flight to there from Charlevoix, Michigan to work at the biological station with CMU professor Kevin Pangle and his graduate student, Mael Glon. With my work at Shedd Aquarium focusing on invasive species and the ongoing management and conservation of the Great Lakes, Kevin, Mael and I have a shared interest in answering an important question: how are freshwater invasive species interacting with, and potentially benefitting, each other?

Invasional Meltdown: Does One Invasive Species Pave the Way for Others?

Approaching Beaver Island from air (Photo credit: Eric Larson)

Ecologists have used the term “invasional meltdown” to refer to the possibility that exotic species might facilitate each other’s invasions, by improving the survival or worsening the impacts of subsequent invaders. The frequency and importance of invasional meltdowns has been debated, but the invasion of the Great Lakes by quagga and zebra mussels is often cited as one of the best examples of this phenomenon. Introduced from Eastern Europe through commercial shipping traffic, these invasive mussels have reengineered the Great Lakes by intercepting, retaining and recycling nutrients in nearshore habitats, depriving open water habitats and their native species of the foundation to their food web. In their place, a suite of lake bottom (or “benthic”) species – including many non-natives – have subsequently thrived.

Two examples —> Read More