The Nature Conservancy and the Virginia Department of Conservation and Recreation are teaming up for a series of free guided hikes at TNC's Mill Creek Springs Natural Area Preserve near Blacksburg. Hikes will be April 22 and 23 at 2, 4 and 6 p.m. Participants should dress for the weather and prepare to get wet feet. Call 804-786-7951 to reserve a spot. Driving directions will be emailed to those who register. Mill Creek Springs contains limestone hills that drain into Mill Creek. Participants will learn how the preserve's karst features are affected by changes in land use. The preserve also is home to a rare red cedar-chinquapin oak dolomite woodland community and a variety of rare invertebrate species. Wildflowers should be in bloom during the hikes.