See how the land has changed over time and the ecological footprints left by those changes. Closed-toe shoes, water and hat recommended. Best for ages 6 and older. 9 to 10:30 a.m. Free; advance registration required. Brooker Creek Preserve, 3940 Keystone Road, Tarpon Springs. (727) 453-6800; www.brookercreekpreserve.org.