Flexing Mussels: Environmental Change In Wisconsin Over 100 Years

When animals die, their bodies leave clues to what they experienced in life. Freshwater mussels live and die at the bottom of rivers and lakes. Their shells are famously variable depending on their environment, sometimes with more variation within a species than between individuals of different species. We are measuring shell characteristics of mussels that have been found throughout Wisconsin during surveys to better understand these animals and their environments. Shells collected from areas with lots of silt and mud have different shapes than those collected from areas with coarser rocks. As the way that we use the land around these water bodies changes, we affect everything that lives in them because the water runs over the land and into streams and rivers. Freshwater mussels are globally endangered and are extremely vulnerable in North America. The Milwaukee Public Museum holds a large collection of mussels from our region that is continuously growing. This collection will allow us to look back at mussels collected in the late nineteenth century and in the 1970's, then compare them to shells collected last summer. This unique set of collections will give us a picture of the changes over more than a century. By exploring geometric morphology among surveys, we will better understand the changing conditions in the rivers and the variability within and among species of mussels.