If you listen to the locals, they'll tell you that Madeline Island is the only one of the Apostle Islands that the NPS "didn't have enough money to buy." Here, on Madeline, are the summer homes of the Maytags and Bristols and, oddly enough, some dude from St. Louis who bought 600 acres of forested land, cleared it, and built two huge greenhouses from which he grows and sells stock plants. And, while what he did with his property did initially shock the old summer families and locals, the fact that he "does well" seems to have made up for his environmental faux pas.
So, the NPS controls all the islands but Madeline and maintains the Apostle Island National Lakeshore (which I still hope to explore day). But, the folks of Madeline, or at least the Wisconsin DNR, are concerned too with preserving the natural beauty of their island. Big Bay State Park is one such area that you can find a healthy dose of nature. We spent a couple of half days there, walking the trails and hanging out at the beach.