Linda Littlefield Grenfell, Environmental Educator and Maine Master Naturalist, will present “Exploring an Ecosystem,” on Saturday, July 15, at 10:00 AM on the St. George River at Payson Park (next to Lincoln’s Country Store), Route 90, Warren. She will describe watershed ecosystems and estuaries using an interactive watershed model, sample the water at the St. George’s head of tide, and lead a short walk on the historic Georges River Canal trail. Sponsored by Nativity Lutheran Church, the event is free and open to all. Bring your love of water, your questions, and a folding chair. Refreshments will be provided. In the event of heavy rain, the event will be held at Nativity Lutheran Church, 179 Old County Road, Rockport. For more information on this presentation and the “Stewarding Our Watersheds: A Precious Gift” series, visit Nativity’s website at nativityrockport.org/stewarding-our-watersheds.