Wildlife and Habitat

The Great Lakes ecosystem supports a wealth of biological diversity, including many species and communities of global significance. Of the animal/plant species and natural community types identified within the Great Lakes basin, 131 of them are deemed critically imperiled, imperiled, or rare on a global scale. The basin is also home to more than 1/10 of the U.S. population and more than 1/4 of the population of Canada. Nearly 25% of the total Canadian agricultural production and 7% of the U.S. agricultural production occur in the basin. Some of the world’s largest concentrations of industrial capacity are located around the Great Lakes. Some of these human activities adversely impact the basin ecosystem and continue to pose threats to the biological diversity in the basin.

 

Locks and dams disrupt river habitats by preventing species of fish and mussels from moving along the river, and keeping submersed vegetation from growing—all of which decreases biodiversity. Locks and dams also stop the normal cycle of flooding, a cycle many animals use to access floodplains for nesting and rearing of offspring.

 

Furthermore, invasive species can disrupt aquatic habitats. For example, silver carp, which were first introduced in the 1970s to help remove algae from catfish farms, have since escaped the farms and migrated up the Mississippi River system. Also known as the flying carp, these fish can grow to 50 or more pounds. The connection between Lake Michigan and the Illinois River acts as a conduit for invasive species—as a result, these fish now threaten to enter the Great Lakes. The carp displace native species of fish by filter feeding and removing the bottom of the food chain for indigenous species.