In the park's formative stages, nearly 300,000 trees and shrubs were planted. More than 120 different kinds of fossils have been identified on park bluffs, many near the 10 popular hiking trails, which total about 12 miles. Richard Keating, a botany professor at Southern Illinois University-Edwardsville, enjoys hiking in the park's backcountry, away from the popular trails. On the St. Andrew Ridge Trail, which starts in Rosedale at the northwest corner of the park, he found a very mature oak-hickory forest in a section that reminds him of the Blue Ridge area of Virginia. They used army trucks and elbow grease to carve it out.
Birds love the park.
Celebrated birder Helen Wuestenfeld of Jerseyville, Illinois, has helped park managers compile an official list of 230 species, including the American bald eagle, dozens of which are seen here each winter. She has personally seen at least 315 bird species, mostly around Pere Marquette as well as nearby Gilbert and Swan Lakes. It wasn't a fly-by, either. It was circling as if looking for food. Then, it flew over the bluffs to hunt in the woods.