Question

so what are some of the challenges to the environment of the Great Lakes

Answer 1

The fish and birds have to adapt to the changes of the water during each season.
Also during the winter when the water freezes people like to go ice fishing and when they cut holes in the ice and take out the ice that was cut the river loses water.

Answer 2

Some challenges are that the great lakes has invasive species,non point source pollution,shoreline development/wetlands,cargo ship channels,point source pollution,pollution hot spots,disappearing native species,air pollution deposition,polluted beaches,and water withdrawals.
Hope I helped