We have the same step on a few areas of our pond, it does leave some shelter for crayfish & frogs, but muskrats also use it as a shelterd run eroding it much more.
I was thinking of using large field stone installed over landscape fabric to keep weeds out, then putting pea stone between grass & stone to make mowing easier. but need a way to stop the rats.
Chain link fencing laid down could keep out the rats?